Southern Power 10-K 15 Feb 23 2022 FY Annual report Financial data

Cover Page

Cover Page - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2022	Jan. 31, 2023	Jun. 30, 2022
Document Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Period End Date	Dec. 31, 2022
Current Fiscal Year End Date	--12-31
Document Transition Report	false
Entity File Number	1-3526
Entity Registrant Name	The Southern Company
Entity Tax Identification Number	58-0690070
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	30 Ivan Allen Jr. Boulevard, N.W.
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30308
City Area Code	404
Local Phone Number	506-5000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 75.8
Entity Common Stock, Shares Outstanding (in shares)		1,088,907,919
Documents Incorporated by Reference	Documents incorporated by reference: specified portions of The Southern Company's Definitive Proxy Statement on Schedule 14A relating to the 2023 Annual Meeting of Stockholders are incorporated by reference into PART III. Each of Alabama Power Company, Georgia Power Company, Mississippi Power Company, Southern Power Company, and Southern Company Gas meets the conditions set forth in General Instructions I(1)(a) and (b) of Form 10-K and is therefore filing this Form 10-K with the reduced disclosure format specified in General Instructions I(2)(b), (c), and (d) of Form 10-K. This combined Form 10-K is separately filed by The Southern Company, Alabama Power Company, Georgia Power Company, Mississippi Power Company, Southern Power Company, and Southern Company Gas. Information contained herein relating to any individual registrant is filed by such registrant on its own behalf. Each registrant makes no representation as to information relating to the other registrants.
Entity Central Index Key	0000092122
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	FY
Common Stock, par value $5 per share
Document Information [Line Items]
Title of 12(b) Security	Common Stock, par value $5 per share
Trading Symbol	SO
Security Exchange Name	NYSE
Series 2017B 5.25% Junior Subordinated Notes due 2077
Document Information [Line Items]
Title of 12(b) Security	Series 2017B 5.25% Junior Subordinated Notes due 2077
Trading Symbol	SOJC
Security Exchange Name	NYSE
Series 2020A 4.95% Junior Subordinated Notes due 2080
Document Information [Line Items]
Title of 12(b) Security	Series 2020A 4.95% Junior Subordinated Notes due 2080
Trading Symbol	SOJD
Security Exchange Name	NYSE
Series 2020C 4.20% Junior Subordinated Notes due 2060
Document Information [Line Items]
Title of 12(b) Security	Series 2020C 4.20% Junior Subordinated Notes due 2060
Trading Symbol	SOJE
Security Exchange Name	NYSE
Series 2021B 1.875% Fixed-to-Fixed Reset Rate Junior Subordinated Notes due 2081
Document Information [Line Items]
Title of 12(b) Security	Series 2021B 1.875% Fixed-to-Fixed Reset Rate Junior Subordinated Notes due 2081
Trading Symbol	SO 81
Security Exchange Name	NYSE
Alabama Power
Document Information [Line Items]
Entity File Number	1-3164
Entity Registrant Name	Alabama Power Company
Entity Tax Identification Number	63-0004250
Entity Incorporation, State or Country Code	AL
Entity Address, Address Line One	600 North 18th Street
Entity Address, City or Town	Birmingham
Entity Address, State or Province	AL
Entity Address, Postal Zip Code	35203
City Area Code	205
Local Phone Number	257-1000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		30,537,500
Entity Central Index Key	0000003153
Georgia Power
Document Information [Line Items]
Entity File Number	1-6468
Entity Registrant Name	Georgia Power Company
Entity Tax Identification Number	58-0257110
Entity Incorporation, State or Country Code	GA
Entity Address, Address Line One	241 Ralph McGill Boulevard, N.E.
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30308
City Area Code	404
Local Phone Number	506-6526
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		9,261,500
Entity Central Index Key	0000041091
Georgia Power | Series 2017A 5.00% Junior Subordinated Notes due 2077
Document Information [Line Items]
Title of 12(b) Security	Series 2017A 5.00% Junior Subordinated Notes due 2077
Trading Symbol	GPJA
Security Exchange Name	NYSE
Mississippi Power
Document Information [Line Items]
Entity File Number	001-11229
Entity Registrant Name	Mississippi Power Company
Entity Tax Identification Number	64-0205820
Entity Incorporation, State or Country Code	MS
Entity Address, Address Line One	2992 West Beach Boulevard
Entity Address, City or Town	Gulfport
Entity Address, State or Province	MS
Entity Address, Postal Zip Code	39501
City Area Code	228
Local Phone Number	864-1211
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		1,121,000
Entity Central Index Key	0000066904
Southern Power
Document Information [Line Items]
Entity File Number	001-37803
Entity Registrant Name	Southern Power Company
Entity Tax Identification Number	58-2598670
Entity Incorporation, State or Country Code	DE
Entity Address, Address Line One	30 Ivan Allen Jr. Boulevard, N.W.
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30308
City Area Code	404
Local Phone Number	506-5000
Entity Well-known Seasoned Issuer	No
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		1,000
Entity Central Index Key	0001160661
Southern Power | Series 2016B 1.850% Senior Notes due 2026
Document Information [Line Items]
Title of 12(b) Security	Series 2016B 1.850% Senior Notes due 2026
Trading Symbol	SO/26A
Security Exchange Name	NYSE
Southern Company Gas
Document Information [Line Items]
Entity File Number	1-14174
Entity Registrant Name	Southern Company Gas
Entity Tax Identification Number	58-2210952
Entity Incorporation, State or Country Code	GA
Entity Address, Address Line One	Ten Peachtree Place, N.E.
Entity Address, City or Town	Atlanta
Entity Address, State or Province	GA
Entity Address, Postal Zip Code	30309
City Area Code	404
Local Phone Number	584-4000
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)		100
Entity Central Index Key	0001004155

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2022
Auditor [Line Items]
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Atlanta, Georgia
Alabama Power
Auditor [Line Items]
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Birmingham, Alabama
Georgia Power
Auditor [Line Items]
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Atlanta, Georgia
Mississippi Power
Auditor [Line Items]
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Atlanta, Georgia
Southern Power
Auditor [Line Items]
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Atlanta, Georgia
Southern Company Gas
Auditor [Line Items]
Auditor Name	Deloitte & Touche LLP
Auditor Firm ID	34
Auditor Location	Atlanta, Georgia
Southern Natural Gas Company, LLC
Auditor [Line Items]
Auditor Name	BDO USA, LLP
Auditor Firm ID	243
Auditor Location	Houston, Texas

Consolidated Statements of Inco

Consolidated Statements of Income - Southern - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Revenues:
Total operating revenues	$ 29,279	$ 23,113	$ 20,375
Operating Expenses:
Other operations and maintenance	6,630	6,088	5,413
Depreciation and amortization	3,663	3,565	3,518
Taxes other than income taxes	1,411	1,290	1,234
Estimated loss on Plant Vogtle Units 3 and 4	183	1,692	325
Impairment charges	251	2	0
Gain on dispositions, net	(57)	(186)	(65)
Total operating expenses	23,909	19,415	15,490
Operating Income	5,370	3,698	4,885
Other Income and (Expense):
Allowance for equity funds used during construction	224	190	149
Earnings from equity method investments	151	76	153
Interest expense, net of amounts capitalized	(2,022)	(1,837)	(1,821)
Impairment of leveraged leases	0	(7)	(206)
Other income (expense), net	500	456	336
Total other income and (expense)	(1,147)	(1,122)	(1,389)
Earnings Before Income Taxes	4,223	2,576	3,496
Income taxes (benefit)	795	267	393
Net Income	3,428	2,309	3,103
Dividends on preferred stock of subsidiaries	11	15	15
Net loss attributable to noncontrolling interests	(107)	(99)	(31)
Consolidated Net Income	$ 3,524	$ 2,393	$ 3,119
Earnings per share —
Basic (in dollars per share)	$ 3.28	$ 2.26	$ 2.95
Diluted (in dollars per share)	$ 3.26	$ 2.24	$ 2.93
Average number of shares of common stock outstanding — (in millions)
Basic (in shares)	1,075	1,061	1,058
Diluted (in shares)	1,081	1,068	1,065
Retail electric revenues
Operating Revenues:
Total operating revenues	$ 18,197	$ 14,852	$ 13,643
Wholesale electric revenues
Operating Revenues:
Total operating revenues	3,641	2,455	1,945
Other electric revenues
Operating Revenues:
Total operating revenues	747	718	672
Natural Gas
Operating Revenues:
Total operating revenues	5,962	4,380	3,434
Natural gas
Operating Expenses:
Cost of sales	3,004	1,619	972
Other revenues
Operating Revenues:
Total operating revenues	732	708	681
Operating Expenses:
Cost of sales	396	357	327
Fuel
Operating Expenses:
Cost of sales	6,835	4,010	2,967
Purchased power
Operating Expenses:
Cost of sales	$ 1,593	$ 978	$ 799

Consolidated Statements of Comp

Consolidated Statements of Comprehensive Income - Southern - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Net Income (Loss)	$ 3,428	$ 2,309	$ 3,103
Qualifying hedges:
Changes in fair value, net of tax	(60)	(49)	10
Reclassification adjustment for amounts included in net income, net of tax	73	96	(40)
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	48	98	(55)
Reclassification adjustment for amounts included in net income, net of tax	10	13	10
Total other comprehensive income (loss)	71	158	(75)
Dividends on preferred stock of subsidiaries	11	15	15
Comprehensive loss attributable to noncontrolling interests	(107)	(99)	(31)
Comprehensive Income (Loss) Attributable to Parent	$ 3,595	$ 2,551	$ 3,044

Consolidated Statements of Co_2

Consolidated Statements of Comprehensive Income - Southern (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Comprehensive Income [Abstract]
Qualifying hedges, change in fair value, tax	$ (19)	$ (16)	$ 3
Qualifying hedges, reclassification adjustment, tax	23	31	(13)
Pension and other postretirement benefit plans, gain (loss), tax	18	37	(17)
Reclassification adjustment for amounts included in net income, tax	$ 3	$ 5	$ 3

Consolidated Statements of Cash

Consolidated Statements of Cash Flows - Southern - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities:
Consolidated net income	$ 3,428	$ 2,309	$ 3,103
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	4,064	3,973	3,905
Deferred income taxes	670	(49)	(241)
Utilization of federal investment tax credits	88	288	341
Allowance for equity funds used during construction	(224)	(190)	(149)
Pension, postretirement, and other employee benefits	(436)	(305)	(261)
Settlement of asset retirement obligations	(455)	(456)	(442)
Storm damage and reliability reserve accruals	430	288	325
Stock based compensation expense	127	144	113
Estimated loss on Plant Vogtle Units 3 and 4	183	1,692	325
Impairment charges	251	91	206
Gain on dispositions, net	(42)	(176)	(66)
Retail fuel cost under recovery – long-term	(2,166)	(536)	0
Natural gas cost under recovery – long-term	207	(207)	0
Other, net	17	87	(75)
Changes in certain current assets and liabilities —
-Receivables	(769)	(81)	(222)
-Fossil fuel for generation	(125)	99	(29)
-Materials and supplies	(160)	(130)	(157)
-Natural gas cost under recovery	158	(266)	0
-Other current assets	(288)	(270)	(132)
-Accounts payable	1,021	(8)	(27)
-Accrued taxes	51	(54)	242
-Customer refunds	119	130	(236)
-Other current liabilities	153	(204)	173
Net cash provided from operating activities	6,302	6,169	6,696
Investing Activities:
Property additions	(7,923)	(7,586)	(7,522)
Nuclear decommissioning trust fund purchases	(1,125)	(1,598)	(877)
Nuclear decommissioning trust fund sales	1,112	1,593	871
Proceeds from dispositions	275	917	1,049
Cost of removal, net of salvage	(649)	(442)	(361)
Payments pursuant to LTSAs	(190)	(188)	(211)
Other investing activities	70	(49)	21
Net cash used for investing activities	(8,430)	(7,353)	(7,030)
Financing Activities:
Increase (decrease) in notes payable, net		530
Increase (decrease) in notes payable, net	(337)		(1,096)
Proceeds —
Long-term debt	5,132	8,262	8,047
Short-term borrowings	2,650	325	615
Common stock	1,808	73	74
Redemptions and repurchases —
Long-term debt	(2,158)	(4,327)	(4,458)
Short-term borrowings	(1,150)	(25)	(840)
Capital contributions from noncontrolling interests	73	501	363
Distributions to noncontrolling interests	(259)	(351)	(271)
Payment of common stock dividends	(2,907)	(2,777)	(2,685)
Other financing activities	(218)	(266)	(325)
Net cash provided from (used for) financing activities	2,336	1,945	(576)
Net Change in Cash, Cash Equivalents, and Restricted Cash	208	761	(910)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	1,829	1,068	1,978
Cash, Cash Equivalents, and Restricted Cash at End of Year	2,037	1,829	1,068
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	1,758	1,718	1,683
Income taxes, net	146	93	64
Noncash transactions —
Accrued property additions at year-end	1,024	866	989
Contributions from noncontrolling interests	15	89	12
Contributions of wind turbine equipment	$ 0	$ 82	$ 17

Consolidated Statements of Ca_2

Consolidated Statements of Cash Flows - Southern (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Cash Flows [Abstract]
Net cash paid for capitalized interest	$ 103	$ 92	$ 81

Consolidated Balance Sheets - S

Consolidated Balance Sheets - Southern - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 1,917	$ 1,798
Receivables —
Customer accounts	2,138	1,806
Unbilled revenues	1,012	711
Other accounts and notes	637	523
Accumulated provision for uncollectible accounts	(71)	(78)
Materials and supplies	1,664	1,543
Fossil fuel for generation	575	450
Natural gas for sale	438	362
Prepaid expenses	347	330
Assets from risk management activities, net of collateral	115	151
Regulatory assets – asset retirement obligations	332	219
Natural gas cost under recovery	108	266
Other regulatory assets	860	653
Other current assets	344	231
Total current assets	10,416	8,965
Property, Plant, and Equipment:
In service	117,529	115,592
Less: Accumulated depreciation	35,297	34,079
Plant in service, net of depreciation	82,232	81,513
Other utility plant, net	599	0
Nuclear fuel, at amortized cost	843	824
Construction work in progress	10,896	8,771
Total property, plant, and equipment	94,570	91,108
Other Property and Investments:
Goodwill	5,161	5,280
Nuclear decommissioning trusts, at fair value	2,145	2,542
Equity investments in unconsolidated subsidiaries	1,443	1,282
Other intangible assets, net of amortization	406	445
Miscellaneous property and investments	602	653
Total other property and investments	9,757	10,202
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,531	1,701
Deferred charges related to income taxes	866	824
Prepaid pension costs	2,290	1,657
Unamortized loss on reacquired debt	238	258
Deferred under recovered fuel clause revenues	2,056	410
Regulatory assets – asset retirement obligations, deferred	5,764	5,466
Other regulatory assets, deferred	5,918	5,577
Other deferred charges and assets	1,485	1,366
Total deferred charges and other assets	20,148	17,259
Total Assets	134,891	127,534
Current Liabilities:
Securities due within one year	4,285	2,157
Notes payable	2,609	1,440
Accounts payable	3,525	2,169
Customer deposits	502	479
Accrued taxes —
Accrued income taxes	60	50
Other accrued taxes	764	641
Accrued interest	614	533
Accrued compensation	1,127	1,070
Asset retirement obligations	694	697
Operating lease obligations	197	250
Other regulatory liabilities	382	563
Other current liabilities	965	872
Total current liabilities	15,724	10,921
Long-Term Debt	50,656	50,120
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	10,036	8,862
Deferred credits related to income taxes	5,235	5,401
Accumulated deferred ITCs	2,133	2,216
Employee benefit obligations	1,238	1,550
Operating lease obligations, deferred	1,388	1,503
Asset retirement obligations, deferred	10,146	10,990
Other cost of removal obligations	1,903	2,103
Other regulatory liabilities, deferred	733	485
Other deferred credits and liabilities	1,167	816
Total deferred credits and other liabilities	33,979	33,926
Total Liabilities	100,359	94,967
Cumulative preferred stock
Redeemable preferred stock	0	291
Common Stockholders' Equity:
Common stock	5,417	5,279
Paid-in capital	13,673	11,950
Treasury, at cost	(53)	(47)
Retained earnings (accumulated deficit)	11,538	10,929
Accumulated other comprehensive loss	(167)	(237)
Total common stockholders' equity	30,408	27,874
Noncontrolling Interests	4,124	4,402
Total Stockholders' Equity (See accompanying statements)	34,532	32,276
Total Liabilities and Stockholders' Equity	134,891	127,534
Commitments and Contingent Matters
Redeemable Preferred Stock, $100 par or stated value
Cumulative preferred stock
Redeemable preferred stock	0	48
Redeemable Preferred Stock, $1 par value
Cumulative preferred stock
Redeemable preferred stock	$ 0	$ 243

Consolidated Balance Sheets -_2

Consolidated Balance Sheets - Southern (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Other intangible assets, amortization	$ 340,000,000	$ 307,000,000
Common Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 5	$ 5
Common stock, shares authorized (in shares)	1,500,000,000	1,500,000,000
Common stock, shares issued (in shares)	1,100,000,000	1,100,000,000
Treasury shares (in shares)	1,000,000	1,000,000
Redeemable Preferred Stock
Cumulative preferred stock
Annual dividend requirement	$ 15,000,000	$ 15,000,000
Redeemable Preferred Stock, $100 par or stated value
Cumulative preferred stock
Par value (in dollars per share)	$ 100	$ 100
Shares authorized (in shares)	10,000,000	10,000,000
Shares outstanding (in shares)	500,000	500,000
Redeemable Preferred Stock, $100 par or stated value | Minimum
Cumulative preferred stock
Dividend rate	4.20%	4.20%
Redeemable Preferred Stock, $100 par or stated value | Maximum
Cumulative preferred stock
Dividend rate	4.92%	4.92%
Redeemable Preferred Stock, $1 par value
Cumulative preferred stock
Par value (in dollars per share)	$ 1	$ 1
Dividend rate	5%	5%
Shares authorized (in shares)	28,000,000	28,000,000
Shares outstanding (in shares)	10,000,000	10,000,000

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity - Southern - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Treasury	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Beginning balance (in shares) at Dec. 31, 2019		1,054	1
Beginning balance at Dec. 31, 2019	$ 31,759	$ 5,257	$ (42)	$ 11,734	$ 10,877	$ (321)	$ 4,254
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income (loss)	3,088				3,119		(31)
Other comprehensive income (loss)	(75)					(75)
Stock issued (in shares)		4
Stock issued	74	$ 11		63
Stock-based compensation	44			44
Cash dividends on common stock	(2,685)				(2,685)
Contributions from noncontrolling interests	307						307
Distributions to noncontrolling interests	(271)						(271)
Purchase of membership interests from noncontrolling interests				5
Purchase of membership interests from noncontrolling interests	(60)						(65)
Sale of noncontrolling interests	65			(2)			67
Other	(12)		$ (4)	(10)		(1)	1
Ending balance (in shares) at Dec. 31, 2020		1,058	1
Ending balance at Dec. 31, 2020	32,234	$ 5,268	$ (46)	11,834	11,311	(395)	4,262
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income (loss)	2,294				2,393		(99)
Other comprehensive income (loss)	158					158
Stock issued (in shares)		3
Stock issued	73	$ 11		62
Stock-based compensation	62			62
Cash dividends on common stock	(2,777)				(2,777)
Contributions from noncontrolling interests	590						590
Distributions to noncontrolling interests	(351)						(351)
Other	(7)		$ (1)	(8)	2
Ending balance (in shares) at Dec. 31, 2021		1,061	1
Ending balance at Dec. 31, 2021	32,276	$ 5,279	$ (47)	11,950	10,929	(237)	4,402
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated net income (loss)	3,417				3,524		(107)
Other comprehensive income (loss)	71					71
Stock issued (in shares)		29
Stock issued	1,808	$ 138		1,670
Stock-based compensation	44			44
Cash dividends on common stock	(2,907)				(2,907)
Contributions from noncontrolling interests	88						88
Distributions to noncontrolling interests	(259)						(259)
Other	(6)		$ (6)	9	(8)	(1)
Ending balance (in shares) at Dec. 31, 2022		1,090	1
Ending balance at Dec. 31, 2022	$ 34,532	$ 5,417	$ (53)	$ 13,673	$ 11,538	$ (167)	$ 4,124

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity - Southern (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Stockholders' Equity [Abstract]
Cash dividends (in dollars per share)	$ 2.7000	$ 2.6200	$ 2.5400

Statements of Income - APC

Statements of Income - APC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Revenues:
Total operating revenues	$ 29,279	$ 23,113	$ 20,375
Operating Expenses:
Other operations and maintenance	6,630	6,088	5,413
Depreciation and amortization	3,663	3,565	3,518
Taxes other than income taxes	1,411	1,290	1,234
Total operating expenses	23,909	19,415	15,490
Operating Income	5,370	3,698	4,885
Other Income and (Expense):
Allowance for equity funds used during construction	224	190	149
Interest expense, net of amounts capitalized	(2,022)	(1,837)	(1,821)
Other income (expense), net	500	456	336
Total other income and (expense)	(1,147)	(1,122)	(1,389)
Earnings Before Income Taxes	4,223	2,576	3,496
Income taxes (benefit)	795	267	393
Net Income (Loss)	3,428	2,309	3,103
Dividends on preferred stock of subsidiaries	11	15	15
Consolidated Net Income	3,524	2,393	3,119
Retail electric revenues
Operating Revenues:
Total operating revenues	18,197	14,852	13,643
Other revenues
Operating Revenues:
Total operating revenues	732	708	681
Operating Expenses:
Cost of sales	396	357	327
Fuel
Operating Expenses:
Cost of sales	6,835	4,010	2,967
Purchased power
Operating Expenses:
Cost of sales	1,593	978	799
Alabama Power
Operating Revenues:
Total operating revenues	7,817	6,413	5,830
Operating Expenses:
Other operations and maintenance	1,935	1,735	1,619
Depreciation and amortization	875	859	812
Taxes other than income taxes	424	410	416
Total operating expenses	5,875	4,607	4,136
Operating Income	1,942	1,806	1,694
Other Income and (Expense):
Allowance for equity funds used during construction	70	52	46
Interest expense, net of amounts capitalized	(382)	(340)	(338)
Other income (expense), net	144	107	100
Total other income and (expense)	(168)	(181)	(192)
Earnings Before Income Taxes	1,774	1,625	1,502
Income taxes (benefit)	423	372	337
Net Income (Loss)	1,351	1,253	1,165
Dividends on preferred stock of subsidiaries	11	15	15
Consolidated Net Income	1,340	1,238	1,150
Alabama Power | Retail electric revenues
Operating Revenues:
Total operating revenues	6,470	5,499	5,213
Alabama Power | Wholesale revenues
Operating Revenues:
Total operating revenues	726	377	269
Alabama Power | Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	202	171	46
Alabama Power | Other revenues
Operating Revenues:
Total operating revenues	419	366	302
Alabama Power | Fuel
Operating Expenses:
Cost of sales	1,840	1,235	970
Alabama Power | Purchased power
Operating Expenses:
Cost of sales	441	221	191
Alabama Power | Purchased power, affiliates
Operating Expenses:
Cost of sales	$ 360	$ 147	$ 128

Statements of Comprehensive Inc

Statements of Comprehensive Income (Loss) - APC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net Income (Loss)	$ 3,428	$ 2,309	$ 3,103
Qualifying hedges:
Changes in fair value, net of tax	(60)	(49)	10
Reclassification adjustment for amounts included in net income, net of tax	73	96	(40)
Current period change	71	158	(75)
Comprehensive Income (Loss) Attributable to Parent	3,595	2,551	3,044
Alabama Power
Net Income (Loss)	1,351	1,253	1,165
Qualifying hedges:
Changes in fair value, net of tax	(1)	2	0
Reclassification adjustment for amounts included in net income, net of tax	5	4	4
Current period change	4	6	4
Comprehensive Income (Loss) Attributable to Parent	$ 1,355	$ 1,259	$ 1,169

Statements of Comprehensive I_2

Statements of Comprehensive Income (Loss) - APC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Qualifying hedges, change in fair value, tax	$ (19)	$ (16)	$ 3
Qualifying hedges, reclassification adjustment, tax	23	31	(13)
Alabama Power
Qualifying hedges, change in fair value, tax	0	1	0
Qualifying hedges, reclassification adjustment, tax	$ 2	$ 2	$ 2

Statements of Cash Flows - APC

Statements of Cash Flows - APC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities:
Consolidated net income	$ 3,428	$ 2,309	$ 3,103
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	4,064	3,973	3,905
Deferred income taxes	670	(49)	(241)
Allowance for equity funds used during construction	(224)	(190)	(149)
Pension, postretirement, and other employee benefits	(436)	(305)	(261)
Settlement of asset retirement obligations	(455)	(456)	(442)
Natural disaster reserve and reliability reserve accruals	430	288	325
Retail fuel cost under recovery – long-term	(2,166)	(536)	0
Other, net	17	87	(75)
Changes in certain current assets and liabilities —
-Receivables	(769)	(81)	(222)
-Materials and supplies	(160)	(130)	(157)
-Other current assets	(288)	(270)	(132)
-Accounts payable	1,021	(8)	(27)
-Accrued taxes	51	(54)	242
-Customer refunds	119	130	(236)
-Other current liabilities	153	(204)	173
Net cash provided from operating activities	6,302	6,169	6,696
Investing Activities:
Property additions	(7,923)	(7,586)	(7,522)
Nuclear decommissioning trust fund purchases	(1,125)	(1,598)	(877)
Nuclear decommissioning trust fund sales	1,112	1,593	871
Cost of removal, net of salvage	(649)	(442)	(361)
Other investing activities	70	(49)	21
Net cash used for investing activities	(8,430)	(7,353)	(7,030)
Redemptions and repurchases —
Preferred stock	(298)	0	0
Payment of common stock dividends	(2,907)	(2,777)	(2,685)
Other financing activities	(218)	(266)	(325)
Net cash provided from (used for) financing activities	2,336	1,945	(576)
Net Change in Cash, Cash Equivalents, and Restricted Cash	208	761	(910)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	1,829	1,068	1,978
Cash, Cash Equivalents, and Restricted Cash at End of Year	2,037	1,829	1,068
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	1,758	1,718	1,683
Income taxes, net	146	93	64
Noncash transactions —
Accrued property additions at year-end	1,024	866	989
Alabama Power
Operating Activities:
Consolidated net income	1,351	1,253	1,165
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	1,014	1,005	963
Deferred income taxes	355	245	78
Allowance for equity funds used during construction	(70)	(52)	(46)
Pension, postretirement, and other employee benefits	(118)	(106)	(90)
Settlement of asset retirement obligations	(205)	(202)	(219)
Natural disaster reserve and reliability reserve accruals	185	75	112
Retail fuel cost under recovery – long-term	(520)	(126)	0
Other, net	(50)	(52)	50
Changes in certain current assets and liabilities —
-Receivables	(321)	42	(49)
-Materials and supplies	(7)	(6)	(47)
-Retail fuel cost under recovery	(102)	0	0
-Other current assets	(93)	44	(66)
-Accounts payable	249	(109)	(90)
-Accrued taxes	(65)	(56)	84
-Customer refunds	5	128	(12)
-Other current liabilities	31	(30)	(91)
Net cash provided from operating activities	1,639	2,053	1,742
Investing Activities:
Property additions	(2,016)	(1,753)	(1,970)
Nuclear decommissioning trust fund purchases	(355)	(638)	(268)
Nuclear decommissioning trust fund sales	354	637	267
Cost of removal, net of salvage	(234)	(165)	(98)
Change in construction payables, net	50	(16)	(34)
Other investing activities	(62)	(26)	(19)
Net cash used for investing activities	(2,263)	(1,961)	(2,122)
Proceeds —
Senior notes	1,700	1,300	600
Revenue bonds	0	0	87
Redemptions and repurchases —
Senior notes	(750)	(200)	(250)
Preferred stock	(298)	0	0
Revenue bonds	0	(65)	(87)
Other long-term debt	0	(206)	0
Capital contributions from parent company	649	636	653
Payment of common stock dividends	(1,016)	(984)	(957)
Other financing activities	(34)	(43)	(30)
Net cash provided from (used for) financing activities	251	438	16
Net Change in Cash, Cash Equivalents, and Restricted Cash	(373)	530	(364)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	1,060	530	894
Cash, Cash Equivalents, and Restricted Cash at End of Year	687	1,060	530
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	342	308	321
Income taxes, net	121	185	187
Noncash transactions —
Accrued property additions at year-end	$ 182	$ 150	$ 166

Statements of Cash Flows - APC

Statements of Cash Flows - APC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net cash paid for capitalized interest	$ 103	$ 92	$ 81
Alabama Power
Net cash paid for capitalized interest	$ 20	$ 15	$ 15

Balance Sheets - APC

Balance Sheets - APC - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 1,917	$ 1,798
Receivables —
Customer accounts	2,138	1,806
Unbilled revenues	1,012	711
Other accounts and notes	637	523
Accumulated provision for uncollectible accounts	(71)	(78)
Fossil fuel for generation	575	450
Materials and supplies	1,664	1,543
Prepaid expenses	347	330
Other regulatory assets	860	653
Other current assets	344	231
Total current assets	10,416	8,965
Property, Plant, and Equipment:
In service	117,529	115,592
Less: Accumulated depreciation	35,297	34,079
Plant in service, net of depreciation	82,232	81,513
Other utility plant, net	599	0
Nuclear fuel, at amortized cost	843	824
Construction work in progress	10,896	8,771
Total property, plant, and equipment	94,570	91,108
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	2,145	2,542
Equity investments in unconsolidated subsidiaries	1,443	1,282
Miscellaneous property and investments	602	653
Total other property and investments	9,757	10,202
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,531	1,701
Deferred charges related to income taxes	866	824
Regulatory assets – asset retirement obligations, deferred	5,764	5,466
Other regulatory assets, deferred	5,918	5,577
Other deferred charges and assets	1,485	1,366
Total deferred charges and other assets	20,148	17,259
Total Assets	134,891	127,534
Current Liabilities:
Securities due within one year	4,285	2,157
Accounts payable —
Customer deposits	502	479
Accrued interest	614	533
Accrued compensation	1,127	1,070
Asset retirement obligations	694	697
Other regulatory liabilities	382	563
Other current liabilities	965	872
Total current liabilities	15,724	10,921
Long-Term Debt	50,656	50,120
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	10,036	8,862
Deferred credits related to income taxes	5,235	5,401
Accumulated deferred ITCs	2,133	2,216
Employee benefit obligations	1,238	1,550
Operating lease obligations, deferred	1,388	1,503
Asset retirement obligations, deferred	10,146	10,990
Other cost of removal obligations	1,903	2,103
Other regulatory liabilities, deferred	733	485
Other deferred credits and liabilities	1,167	816
Total deferred credits and other liabilities	33,979	33,926
Total Liabilities	100,359	94,967
Cumulative preferred stock
Redeemable preferred stock	0	291
Common Stockholders' Equity:
Common stock	5,417	5,279
Paid-in capital	13,673	11,950
Retained earnings (accumulated deficit)	11,538	10,929
Accumulated other comprehensive loss	(167)	(237)
Total Stockholders' Equity (See accompanying statements)	34,532	32,276
Total Liabilities and Stockholders' Equity	134,891	127,534
Commitments and Contingent Matters
Redeemable Preferred Stock, $100 par or stated value
Cumulative preferred stock
Redeemable preferred stock	0	48
Redeemable Preferred Stock, $1 par value
Cumulative preferred stock
Redeemable preferred stock	0	243
Alabama Power
Current Assets:
Cash and cash equivalents	687	1,060
Receivables —
Customer accounts	431	410
Unbilled revenues	174	138
Affiliated	101	37
Other accounts and notes	153	55
Accumulated provision for uncollectible accounts	(14)	(14)
Fossil fuel for generation	229	159
Materials and supplies	557	548
Prepaid expenses	65	41
Other regulatory assets	474	208
Other current assets	67	67
Total current assets	2,924	2,709
Property, Plant, and Equipment:
In service	33,472	33,135
Less: Accumulated depreciation	10,470	10,313
Plant in service, net of depreciation	23,002	22,822
Other utility plant, net	599	0
Nuclear fuel, at amortized cost	239	247
Construction work in progress	1,526	1,147
Total property, plant, and equipment	25,366	24,216
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	1,127	1,325
Equity investments in unconsolidated subsidiaries	57	57
Miscellaneous property and investments	124	126
Total other property and investments	1,308	1,508
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	71	108
Deferred charges related to income taxes	250	240
Prepaid pension and other postretirement benefit costs	657	513
Regulatory assets – asset retirement obligations, deferred	1,845	1,547
Other regulatory assets, deferred	2,107	1,807
Other deferred charges and assets	442	334
Total deferred charges and other assets	5,372	4,549
Total Assets	34,970	32,982
Current Liabilities:
Securities due within one year	301	751
Accounts payable —
Affiliated	443	309
Other	641	459
Customer deposits	106	106
Accrued taxes	57	98
Accrued interest	120	100
Accrued compensation	229	219
Asset retirement obligations	330	320
Other regulatory liabilities	96	215
Other current liabilities	91	125
Total current liabilities	2,414	2,702
Long-Term Debt	10,329	8,936
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	3,981	3,573
Deferred credits related to income taxes	1,925	1,968
Accumulated deferred ITCs	81	88
Employee benefit obligations	145	171
Operating lease obligations, deferred	67	66
Asset retirement obligations, deferred	3,957	4,014
Other cost of removal obligations	0	192
Other regulatory liabilities, deferred	315	210
Other deferred credits and liabilities	69	58
Total deferred credits and other liabilities	10,540	10,340
Total Liabilities	23,283	21,978
Cumulative preferred stock
Redeemable preferred stock	0	291
Common Stockholders' Equity:
Common stock	1,222	1,222
Paid-in capital	6,710	6,056
Retained earnings (accumulated deficit)	3,764	3,448
Accumulated other comprehensive loss	(9)	(13)
Total Stockholders' Equity (See accompanying statements)	11,687	10,713
Total Liabilities and Stockholders' Equity	34,970	32,982
Commitments and Contingent Matters
Alabama Power | Redeemable Preferred Stock, $100 par or stated value
Cumulative preferred stock
Redeemable preferred stock	0	48
Alabama Power | Redeemable Preferred Stock, $1 par value
Cumulative preferred stock
Redeemable preferred stock	$ 0	$ 243

Balance Sheets - APC (Parenthet

Balance Sheets - APC (Parenthetical) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Common Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 5	$ 5
Common stock, shares authorized (in shares)	1,500,000,000	1,500,000,000
Redeemable Preferred Stock
Cumulative preferred stock
Annual dividend requirement	$ 15,000,000	$ 15,000,000
Redeemable Preferred Stock, $100 par or stated value
Cumulative preferred stock
Par value (in dollars per share)	$ 100	$ 100
Shares authorized (in shares)	10,000,000	10,000,000
Shares outstanding (in shares)	500,000	500,000
Redeemable Preferred Stock, $100 par or stated value | Minimum
Cumulative preferred stock
Dividend rate	4.20%	4.20%
Redeemable Preferred Stock, $100 par or stated value | Maximum
Cumulative preferred stock
Dividend rate	4.92%	4.92%
Redeemable Preferred Stock, $1 par value
Cumulative preferred stock
Par value (in dollars per share)	$ 1	$ 1
Dividend rate	5%	5%
Shares authorized (in shares)	28,000,000	28,000,000
Shares outstanding (in shares)	10,000,000	10,000,000
Alabama Power
Common Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 40	$ 40
Common stock, shares authorized (in shares)	40,000,000	40,000,000
Common stock, shares outstanding (in shares)	31,000,000	31,000,000
Alabama Power | Redeemable Preferred Stock
Cumulative preferred stock
Annual dividend requirement	$ 15,000,000	$ 15,000,000
Alabama Power | Redeemable Preferred Stock, $100 par or stated value
Cumulative preferred stock
Par value (in dollars per share)	$ 100	$ 100
Shares authorized (in shares)	3,900,000	3,900,000
Shares outstanding (in shares)		500,000
Alabama Power | Redeemable Preferred Stock, $100 par or stated value | Minimum
Cumulative preferred stock
Dividend rate	4.20%	4.20%
Alabama Power | Redeemable Preferred Stock, $100 par or stated value | Maximum
Cumulative preferred stock
Dividend rate	4.92%	4.92%
Alabama Power | Redeemable Preferred Stock, $1 par value
Cumulative preferred stock
Par value (in dollars per share)	$ 1	$ 1
Dividend rate	5%	5%
Shares authorized (in shares)	27,500,000	27,500,000
Common Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 25	$ 25
Common stock, shares outstanding (in shares)		10,000,000

Statements of Common Stockholde

Statements of Common Stockholders' Equity - APC - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Alabama Power	Alabama Power Common Stock	Alabama Power Paid-In Capital	Alabama Power Retained Earnings	Alabama Power Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2019		1,054					31
Beginning balance at Dec. 31, 2019	$ 31,759	$ 5,257	$ 11,734	$ 10,877	$ (321)	$ 8,955	$ 1,222	$ 4,755	$ 3,001	$ (23)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated Net Income	3,119					1,150			1,150
Capital contributions from parent company						658		658
Other comprehensive income (loss)	(75)				(75)	4				4
Cash dividends on common stock	(2,685)			(2,685)		(957)			(957)
Other	12		10		1
Ending balance (in shares) at Dec. 31, 2020		1,058					31
Ending balance at Dec. 31, 2020	32,234	$ 5,268	11,834	11,311	(395)	9,810	$ 1,222	5,413	3,194	(19)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated Net Income	2,393					1,238			1,238
Capital contributions from parent company						643		643
Other comprehensive income (loss)	158				158	6				6
Cash dividends on common stock	(2,777)			(2,777)		(984)			(984)
Other	7		8	(2)
Ending balance (in shares) at Dec. 31, 2021		1,061					31
Ending balance at Dec. 31, 2021	32,276	$ 5,279	11,950	10,929	(237)	10,713	$ 1,222	6,056	3,448	(13)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated Net Income	3,524					1,340			1,340
Capital contributions from parent company						654		654
Other comprehensive income (loss)	71				71	4				4
Cash dividends on common stock	(2,907)			(2,907)		(1,016)			(1,016)
Other	6		(9)	8	1	(8)			(8)
Ending balance (in shares) at Dec. 31, 2022		1,090					31
Ending balance at Dec. 31, 2022	$ 34,532	$ 5,417	$ 13,673	$ 11,538	$ (167)	$ 11,687	$ 1,222	$ 6,710	$ 3,764	$ (9)

Statements of Income - GPC

Statements of Income - GPC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Revenues:
Total operating revenues	$ 29,279	$ 23,113	$ 20,375
Operating Expenses:
Other operations and maintenance	6,630	6,088	5,413
Depreciation and amortization	3,663	3,565	3,518
Taxes other than income taxes	1,411	1,290	1,234
Estimated loss on Plant Vogtle Units 3 and 4	183	1,692	325
Total operating expenses	23,909	19,415	15,490
Operating Income	5,370	3,698	4,885
Other Income and (Expense):
Allowance for equity funds used during construction	224	190	149
Interest expense, net of amounts capitalized	(2,022)	(1,837)	(1,821)
Other income (expense), net	500	456	336
Total other income and (expense)	(1,147)	(1,122)	(1,389)
Earnings Before Income Taxes	4,223	2,576	3,496
Income taxes (benefit)	795	267	393
Net Income (Loss)	3,428	2,309	3,103
Net income after dividends on preferred stock	3,524	2,393	3,119
Retail electric revenues
Operating Revenues:
Total operating revenues	18,197	14,852	13,643
Other revenues
Operating Revenues:
Total operating revenues	732	708	681
Operating Expenses:
Cost of sales	396	357	327
Fuel
Operating Expenses:
Cost of sales	6,835	4,010	2,967
Purchased power
Operating Expenses:
Cost of sales	1,593	978	799
Georgia Power
Operating Revenues:
Total operating revenues	11,584	9,260	8,309
Operating Expenses:
Other operations and maintenance	2,349	2,213	1,953
Depreciation and amortization	1,430	1,371	1,425
Taxes other than income taxes	527	476	444
Estimated loss on Plant Vogtle Units 3 and 4	183	1,692	325
Total operating expenses	9,232	8,692	6,337
Operating Income	2,352	568	1,972
Other Income and (Expense):
Allowance for equity funds used during construction	140	127	91
Interest expense, net of amounts capitalized	(485)	(421)	(425)
Other income (expense), net	176	142	89
Total other income and (expense)	(169)	(152)	(245)
Earnings Before Income Taxes	2,183	416	1,727
Income taxes (benefit)	370	(168)	152
Net Income (Loss)	1,813	584	1,575
Georgia Power | Retail electric revenues
Operating Revenues:
Total operating revenues	10,792	8,478	7,609
Georgia Power | Wholesale revenues
Operating Revenues:
Total operating revenues	235	197	115
Georgia Power | Other revenues
Operating Revenues:
Total operating revenues	557	585	585
Georgia Power | Fuel
Operating Expenses:
Cost of sales	2,486	1,449	1,141
Georgia Power | Purchased power
Operating Expenses:
Cost of sales	856	632	540
Georgia Power | Purchased power, affiliates
Operating Expenses:
Cost of sales	$ 1,401	$ 859	$ 509

Statements of Comprehensive I_3

Statements of Comprehensive Income (Loss) - GPC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net Income (Loss)	$ 3,428	$ 2,309	$ 3,103
Qualifying hedges:
Changes in fair value, net of tax	(60)	(49)	10
Reclassification adjustment for amounts included in net income, net of tax	73	96	(40)
Current period change	71	158	(75)
Comprehensive Income (Loss) Attributable to Parent	3,595	2,551	3,044
Georgia Power
Net Income (Loss)	1,813	584	1,575
Qualifying hedges:
Changes in fair value, net of tax	23	0	(2)
Reclassification adjustment for amounts included in net income, net of tax	5	6	6
Current period change	28	6	4
Comprehensive Income (Loss) Attributable to Parent	$ 1,841	$ 590	$ 1,579

Statements of Comprehensive I_4

Statements of Comprehensive Income (Loss) - GPC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Qualifying hedges, change in fair value, tax	$ (19)	$ (16)	$ 3
Qualifying hedges, reclassification adjustment, tax	23	31	(13)
Georgia Power
Qualifying hedges, change in fair value, tax	8	0	(1)
Qualifying hedges, reclassification adjustment, tax	$ 2	$ 2	$ 2

Statements of Cash Flows - GPC

Statements of Cash Flows - GPC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities:
Consolidated net income	$ 3,428	$ 2,309	$ 3,103
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	4,064	3,973	3,905
Deferred income taxes	670	(49)	(241)
Allowance for equity funds used during construction	(224)	(190)	(149)
Pension, postretirement, and other employee benefits	(436)	(305)	(261)
Settlement of asset retirement obligations	(455)	(456)	(442)
Estimated loss on Plant Vogtle Units 3 and 4	183	1,692	325
Other, net	17	87	(75)
Changes in certain current assets and liabilities —
-Receivables	(769)	(81)	(222)
-Fossil fuel for generation	(125)	99	(29)
-Materials and supplies	(160)	(130)	(157)
-Other current assets	(288)	(270)	(132)
-Accounts payable	1,021	(8)	(27)
-Accrued taxes	51	(54)	242
-Customer refunds	119	130	(236)
-Other current liabilities	153	(204)	173
Net cash provided from operating activities	6,302	6,169	6,696
Investing Activities:
Property additions	(7,923)	(7,586)	(7,522)
Nuclear decommissioning trust fund purchases	(1,125)	(1,598)	(877)
Nuclear decommissioning trust fund sales	1,112	1,593	871
Cost of removal, net of salvage	(649)	(442)	(361)
Payments pursuant to LTSAs	(190)	(188)	(211)
Other investing activities	70	(49)	21
Net cash used for investing activities	(8,430)	(7,353)	(7,030)
Financing Activities:
Increase (decrease) in notes payable, net	(337)		(1,096)
Proceeds —
Short-term borrowings	2,650	325	615
Redemptions and repurchases —
Short-term borrowings	(1,150)	(25)	(840)
Payment of common stock dividends	(2,907)	(2,777)	(2,685)
Other financing activities	(218)	(266)	(325)
Net cash provided from (used for) financing activities	2,336	1,945	(576)
Net Change in Cash, Cash Equivalents, and Restricted Cash	208	761	(910)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	1,829	1,068	1,978
Cash, Cash Equivalents, and Restricted Cash at End of Year	2,037	1,829	1,068
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	1,758	1,718	1,683
Income taxes, net	146	93	64
Noncash transactions —
Accrued property additions at year-end	1,024	866	989
Georgia Power
Operating Activities:
Consolidated net income	1,813	584	1,575
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	1,622	1,557	1,607
Deferred income taxes	313	(550)	(273)
Allowance for equity funds used during construction	(140)	(127)	(91)
Pension, postretirement, and other employee benefits	(240)	(148)	(137)
Settlement of asset retirement obligations	(212)	(210)	(185)
Storm damage and reliability reserve accruals	213	213	213
Retail fuel cost recovery – long-term	(1,646)	(410)	(73)
Estimated loss on Plant Vogtle Units 3 and 4	183	1,692	325
Other, net	81	53	14
Changes in certain current assets and liabilities —
-Receivables	(286)	81	(114)
-Fossil fuel for generation	(43)	30	(6)
-Materials and supplies	(73)	(82)	(91)
-Other current assets	(83)	(30)	(48)
-Accounts payable	264	186	59
-Accrued taxes	173	21	55
-Retail fuel cost over recovery	0	(113)	113
-Customer refunds	113	1	(223)
-Other current liabilities	(14)	(1)	64
Net cash provided from operating activities	2,038	2,747	2,784
Investing Activities:
Property additions	(3,901)	(3,376)	(3,445)
Nuclear decommissioning trust fund purchases	(770)	(960)	(609)
Nuclear decommissioning trust fund sales	758	956	604
Cost of removal, net of salvage	(274)	(149)	(143)
Change in construction payables, net of joint owner portion	186	(65)	16
Payments pursuant to LTSAs	(44)	(42)	(86)
Contributions in aid of construction	92	65	20
Proceeds from dispositions	56	8	153
Other investing activities	(57)	(27)	(13)
Net cash used for investing activities	(3,954)	(3,590)	(3,503)
Financing Activities:
Increase (decrease) in notes payable, net	0	(60)	(55)
Proceeds —
Senior notes	1,500	750	1,500
FFB loan	0	440	848
Revenue bonds	200	122	53
Short-term borrowings	2,100	0	250
Redemptions and repurchases —
Senior notes	(400)	(325)	(950)
FFB loan	(88)	(96)	(73)
Revenue bonds	(53)	(69)	(336)
Short-term borrowings	(500)	0	(375)
Other long-term debt	(125)	0	0
Capital contributions from parent company	1,471	1,782	1,392
Payment of common stock dividends	(1,691)	(1,649)	(1,542)
Other financing activities	(51)	(28)	(36)
Net cash provided from (used for) financing activities	2,363	867	676
Net Change in Cash, Cash Equivalents, and Restricted Cash	447	24	(43)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	33	9	52
Cash, Cash Equivalents, and Restricted Cash at End of Year	480	33	9
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	432	382	380
Income taxes, net	30	305	373
Noncash transactions —
Accrued property additions at year-end	$ 626	$ 479	$ 553

Statements of Cash Flows - GPC

Statements of Cash Flows - GPC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net cash paid for capitalized interest	$ 103	$ 92	$ 81
Georgia Power
Net cash paid for capitalized interest	$ 73	$ 63	$ 47

Balance Sheets - GPC

Balance Sheets - GPC - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 1,917	$ 1,798
Receivables —
Customer accounts	2,138	1,806
Unbilled revenues	1,012	711
Other accounts and notes	637	523
Fossil fuel for generation	575	450
Materials and supplies	1,664	1,543
Regulatory assets – asset retirement obligations	332	219
Other regulatory assets	860	653
Other current assets	344	231
Total current assets	10,416	8,965
Property, Plant, and Equipment:
In service	117,529	115,592
Less: Accumulated depreciation	35,297	34,079
Plant in service, net of depreciation	82,232	81,513
Nuclear fuel, at amortized cost	843	824
Construction work in progress	10,896	8,771
Total property, plant, and equipment	94,570	91,108
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	2,145	2,542
Equity investments in unconsolidated subsidiaries	1,443	1,282
Miscellaneous property and investments	602	653
Total other property and investments	9,757	10,202
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,531	1,701
Deferred charges related to income taxes	866	824
Prepaid pension costs	2,290	1,657
Deferred under recovered fuel clause revenues	2,056	410
Regulatory assets – asset retirement obligations, deferred	5,764	5,466
Other regulatory assets, deferred	5,918	5,577
Other deferred charges and assets	1,485	1,366
Deferred cloud implementation costs	20,148	17,259
Total Assets	134,891	127,534
Current Liabilities:
Securities due within one year	4,285	2,157
Notes payable	2,609	1,440
Accounts payable —
Customer deposits	502	479
Accrued interest	614	533
Accrued compensation	1,127	1,070
Operating lease obligations	197	250
Asset retirement obligations	694	697
Other regulatory liabilities	382	563
Other current liabilities	965	872
Total current liabilities	15,724	10,921
Long-Term Debt	50,656	50,120
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	10,036	8,862
Deferred credits related to income taxes	5,235	5,401
Accumulated deferred ITCs	2,133	2,216
Employee benefit obligations	1,238	1,550
Operating lease obligations, deferred	1,388	1,503
Asset retirement obligations, deferred	10,146	10,990
Other deferred credits and liabilities	1,167	816
Total deferred credits and other liabilities	33,979	33,926
Total Liabilities	100,359	94,967
Common Stockholders' Equity:
Common stock	5,417	5,279
Paid-in capital	13,673	11,950
Retained earnings (accumulated deficit)	11,538	10,929
Accumulated other comprehensive loss	(167)	(237)
Total Stockholders' Equity (See accompanying statements)	34,532	32,276
Total Liabilities and Stockholders' Equity	134,891	127,534
Commitments and Contingent Matters
Georgia Power
Current Assets:
Cash and cash equivalents	364	33
Receivables —
Customer accounts	735	547
Unbilled revenues	309	231
Joint owner accounts	128	116
Affiliated	53	25
Other accounts and notes	62	44
Fossil fuel for generation	291	248
Materials and supplies	729	670
Regulatory assets – asset retirement obligations	158	178
Other regulatory assets	324	289
Other current assets	246	178
Total current assets	3,399	2,559
Property, Plant, and Equipment:
In service	41,879	41,332
Less: Accumulated depreciation	13,115	12,854
Plant in service, net of depreciation	28,764	28,478
Nuclear fuel, at amortized cost	604	577
Construction work in progress	8,103	6,688
Total property, plant, and equipment	37,471	35,743
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	1,018	1,217
Equity investments in unconsolidated subsidiaries	51	50
Miscellaneous property and investments	107	69
Total other property and investments	1,176	1,336
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,007	1,157
Deferred charges related to income taxes	583	550
Prepaid pension costs	738	563
Deferred under recovered fuel clause revenues	2,056	410
Regulatory assets – asset retirement obligations, deferred	3,671	3,688
Other regulatory assets, deferred	2,522	1,964
Other deferred charges and assets	540	491
Deferred cloud implementation costs	11,117	8,823
Total Assets	53,163	48,461
Current Liabilities:
Securities due within one year	901	675
Notes payable	1,600	0
Accounts payable —
Affiliated	928	757
Other	1,076	702
Customer deposits	252	259
Accrued taxes	508	335
Accrued interest	157	136
Accrued compensation	254	232
Operating lease obligations	151	156
Asset retirement obligations	295	317
Other regulatory liabilities	170	280
Other current liabilities	286	254
Total current liabilities	6,578	4,103
Long-Term Debt	14,009	13,109
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	3,707	3,019
Deferred credits related to income taxes	2,244	2,321
Accumulated deferred ITCs	319	328
Employee benefit obligations	318	402
Operating lease obligations, deferred	851	999
Asset retirement obligations, deferred	5,739	6,507
Other deferred credits and liabilities	540	439
Total deferred credits and other liabilities	13,718	14,015
Total Liabilities	34,305	31,227
Common Stockholders' Equity:
Common stock	398	398
Paid-in capital	15,626	14,153
Retained earnings (accumulated deficit)	2,846	2,724
Accumulated other comprehensive loss	(12)	(41)
Total Stockholders' Equity (See accompanying statements)	18,858	17,234
Total Liabilities and Stockholders' Equity	53,163	48,461
Commitments and Contingent Matters

Balance Sheets - GPC (Parenthet

Balance Sheets - GPC (Parenthetical) - shares	Dec. 31, 2022	Dec. 31, 2021
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	1,500,000,000	1,500,000,000
Georgia Power
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	20,000,000	20,000,000
Common stock, shares outstanding (in shares)	9,000,000	9,000,000

Statements of Common Stockhol_2

Statements of Common Stockholders' Equity - GPC - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Georgia Power	Georgia Power Common Stock	Georgia Power Paid-In Capital	Georgia Power Retained Earnings	Georgia Power Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2019		1,054					9
Beginning balance at Dec. 31, 2019	$ 31,759	$ 5,257	$ 11,734	$ 10,877	$ (321)	$ 15,065	$ 398	$ 10,962	$ 3,756	$ (51)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	3,103					1,575			1,575
Capital contributions from parent company						1,399		1,399
Other comprehensive income (loss)	(75)				(75)	4				4
Cash dividends on common stock	(2,685)			(2,685)		(1,542)			(1,542)
Other	12		10		1
Ending balance (in shares) at Dec. 31, 2020		1,058					9
Ending balance at Dec. 31, 2020	32,234	$ 5,268	11,834	11,311	(395)	16,501	$ 398	12,361	3,789	(47)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	2,309					584			584
Capital contributions from parent company						1,792		1,792
Other comprehensive income (loss)	158				158	6				6
Cash dividends on common stock	(2,777)			(2,777)		(1,649)			(1,649)
Other	7		8	(2)
Ending balance (in shares) at Dec. 31, 2021		1,061					9
Ending balance at Dec. 31, 2021	32,276	$ 5,279	11,950	10,929	(237)	17,234	$ 398	14,153	2,724	(41)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	3,428					1,813			1,813
Capital contributions from parent company						1,473		1,473
Other comprehensive income (loss)	71				71	28				28
Cash dividends on common stock	(2,907)			(2,907)		(1,691)			(1,691)
Other	6		(9)	8	1	1				1
Ending balance (in shares) at Dec. 31, 2022		1,090					9
Ending balance at Dec. 31, 2022	$ 34,532	$ 5,417	$ 13,673	$ 11,538	$ (167)	$ 18,858	$ 398	$ 15,626	$ 2,846	$ (12)

Statements of Common Stockhol_3

Statements of Common Stockholders' Equity - GPC (Parenthetical) - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Statement of Stockholders' Equity [Abstract]
Cash dividends (in dollars per share)	$ 2.7000	$ 2.6200	$ 2.5400

Statements of Income - MPC

Statements of Income - MPC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Revenues:
Total operating revenues	$ 29,279	$ 23,113	$ 20,375
Operating Expenses:
Other operations and maintenance	6,630	6,088	5,413
Depreciation and amortization	3,663	3,565	3,518
Taxes other than income taxes	1,411	1,290	1,234
Total operating expenses	23,909	19,415	15,490
Operating Income	5,370	3,698	4,885
Other Income and (Expense):
Interest expense, net of amounts capitalized	(2,022)	(1,837)	(1,821)
Other income (expense), net	500	456	336
Total other income and (expense)	(1,147)	(1,122)	(1,389)
Earnings Before Income Taxes	4,223	2,576	3,496
Income taxes (benefit)	795	267	393
Net Income (Loss)	3,428	2,309	3,103
Retail electric revenues
Operating Revenues:
Total operating revenues	18,197	14,852	13,643
Other revenues
Operating Revenues:
Total operating revenues	732	708	681
Operating Expenses:
Cost of sales	396	357	327
Mississippi Power
Operating Revenues:
Total operating revenues	1,694	1,322	1,172
Operating Expenses:
Other operations and maintenance	376	313	284
Depreciation and amortization	181	180	183
Taxes other than income taxes	124	128	124
Total operating expenses	1,470	1,117	963
Operating Income	224	205	209
Other Income and (Expense):
Interest expense, net of amounts capitalized	(56)	(60)	(60)
Other income (expense), net	33	35	17
Total other income and (expense)	(23)	(25)	(43)
Earnings Before Income Taxes	201	180	166
Income taxes (benefit)	37	21	14
Net Income (Loss)	164	159	152
Mississippi Power | Retail electric revenues
Operating Revenues:
Total operating revenues	935	875	821
Mississippi Power | Wholesale revenues
Operating Revenues:
Total operating revenues	252	230	215
Mississippi Power | Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	460	188	111
Mississippi Power | Other revenues
Operating Revenues:
Total operating revenues	47	29	25
Mississippi Power | Fuel and purchased power
Operating Expenses:
Cost of sales	$ 789	$ 496	$ 372

Statements of Comprehensive I_5

Statements of Comprehensive Income - MPC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net Income (Loss)	$ 3,428	$ 2,309	$ 3,103
Qualifying hedges:
Reclassification adjustment for amounts included in net income, net of tax	73	96	(40)
Current period change	71	158	(75)
Comprehensive Income (Loss) Attributable to Parent	3,595	2,551	3,044
Mississippi Power
Net Income (Loss)	164	159	152
Qualifying hedges:
Reclassification adjustment for amounts included in net income, net of tax	0	1	1
Current period change	0	1	1
Comprehensive Income (Loss) Attributable to Parent	$ 164	$ 160	$ 153

Statements of Comprehensive I_6

Statements of Comprehensive Income - MPC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Qualifying hedges, reclassification adjustment, tax	$ 23	$ 31	$ (13)
Mississippi Power
Qualifying hedges, reclassification adjustment, tax	$ 0	$ 0	$ 0

Statements of Cash Flows - MPC

Statements of Cash Flows - MPC - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities:
Consolidated net income	$ 3,428,000	$ 2,309,000	$ 3,103,000
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	4,064,000	3,973,000	3,905,000
Settlement of asset retirement obligations	(455,000)	(456,000)	(442,000)
Other, net	17,000	87,000	(75,000)
Changes in certain current assets and liabilities —
-Receivables	(769,000)	(81,000)	(222,000)
-Other current assets	(288,000)	(270,000)	(132,000)
-Accounts payable	1,021,000	(8,000)	(27,000)
-Other current liabilities	153,000	(204,000)	173,000
Net cash provided from operating activities	6,302,000	6,169,000	6,696,000
Investing Activities:
Property additions	(7,923,000)	(7,586,000)	(7,522,000)
Payments pursuant to LTSAs	(190,000)	(188,000)	(211,000)
Other investing activities	70,000	(49,000)	21,000
Net cash used for investing activities	(8,430,000)	(7,353,000)	(7,030,000)
Financing Activities:
Increase (decrease) in notes payable, net		530,000
Increase (decrease) in notes payable, net	(337,000)		(1,096,000)
Proceeds —
Short-term borrowings	2,650,000	325,000	615,000
Redemptions and repurchases —
Short-term borrowings	(1,150,000)	(25,000)	(840,000)
Payment of common stock dividends	(2,907,000)	(2,777,000)	(2,685,000)
Other financing activities	(218,000)	(266,000)	(325,000)
Net cash provided from (used for) financing activities	2,336,000	1,945,000	(576,000)
Net Change in Cash, Cash Equivalents, and Restricted Cash	208,000	761,000	(910,000)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	1,829,000	1,068,000	1,978,000
Cash, Cash Equivalents, and Restricted Cash at End of Year	2,037,000	1,829,000	1,068,000
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	1,758,000	1,718,000	1,683,000
Income taxes, net	146,000	93,000	64,000
Noncash transactions —
Accrued property additions at year-end	1,024,000	866,000	989,000
Mississippi Power
Operating Activities:
Consolidated net income	164,000	159,000	152,000
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	223,000	213,000	191,000
Settlement of asset retirement obligations	(20,000)	(24,000)	(22,000)
System restoration rider and reliability reserve accruals	32,000	(2,000)	1,000
Other, net	(2,000)	(35,000)	(6,000)
Changes in certain current assets and liabilities —
-Receivables	(82,000)	9,000	(7,000)
-Other current assets	(25,000)	(6,000)	(31,000)
-Accounts payable	97,000	(35,000)	20,000
-Over recovered regulatory clause revenues	0	(34,000)	5,000
-Other current liabilities	(4,000)	1,000	(5,000)
Net cash provided from operating activities	383,000	246,000	298,000
Investing Activities:
Property additions	(276,000)	(213,000)	(274,000)
Payments pursuant to LTSAs	(29,000)	(29,000)	(28,000)
Contributions in aid of construction	19,000	15,000	0
Other investing activities	(31,000)	(30,000)	(21,000)
Net cash used for investing activities	(317,000)	(257,000)	(323,000)
Financing Activities:
Increase (decrease) in notes payable, net			25,000
Increase (decrease) in notes payable, net	0	(25,000)
Proceeds —
Senior notes	0	525,000	0
Short-term borrowings	0	0	40,000
Revenue bonds	35,000	0	34,000
Other long-term debt	0	0	100,000
Redemptions and repurchases —
Senior notes	0	0	(275,000)
Short-term borrowings	0	0	(40,000)
Revenue bonds	0	(320,000)	(41,000)
Other long-term debt	0	(100,000)	0
Capital contributions from parent company	68,000	120,000	85,000
Return of capital to parent company	0	0	(74,000)
Payment of common stock dividends	(170,000)	(157,000)	(74,000)
Other financing activities	(1,000)	(10,000)	(2,000)
Net cash provided from (used for) financing activities	(68,000)	33,000	(222,000)
Net Change in Cash, Cash Equivalents, and Restricted Cash	(2,000)	22,000	(247,000)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	61,000	39,000	286,000
Cash, Cash Equivalents, and Restricted Cash at End of Year	59,000	61,000	39,000
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	55,000	58,000	63,000
Income taxes, net	33,000	16,000	28,000
Noncash transactions —
Accrued property additions at year-end	$ 22,000	$ 25,000	$ 34,000

Statements of Cash Flows - MPC

Statements of Cash Flows - MPC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net cash paid for capitalized interest	$ 103	$ 92	$ 81

Balance Sheets - MPC

Balance Sheets - MPC - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 1,917	$ 1,798
Receivables —
Customer accounts	2,138	1,806
Unbilled revenues	1,012	711
Other accounts and notes	637	523
Fossil fuel for generation	575	450
Materials and supplies	1,664	1,543
Other regulatory assets	860	653
Other current assets	344	231
Total current assets	10,416	8,965
Property, Plant, and Equipment:
In service	117,529	115,592
Less: Accumulated depreciation	35,297	34,079
Plant in service, net of depreciation	82,232	81,513
Construction work in progress	10,896	8,771
Total property, plant, and equipment	94,570	91,108
Other Property and Investments:
Total other property and investments	9,757	10,202
Deferred Charges and Other Assets:
Deferred charges related to income taxes	866	824
Regulatory assets – asset retirement obligations, deferred	5,764	5,466
Other regulatory assets, deferred	5,918	5,577
Other deferred charges and assets	1,485	1,366
Total deferred charges and other assets	20,148	17,259
Total Assets	134,891	127,534
Current Liabilities:
Securities due within one year	4,285	2,157
Accounts payable —
Accrued compensation	1,127	1,070
Asset retirement obligations	694	697
Other regulatory liabilities	382	563
Other current liabilities	965	872
Total current liabilities	15,724	10,921
Long-Term Debt	50,656	50,120
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	10,036	8,862
Deferred credits related to income taxes	5,235	5,401
Employee benefit obligations	1,238	1,550
Asset retirement obligations, deferred	10,146	10,990
Other cost of removal obligations	1,903	2,103
Other regulatory liabilities, deferred	733	485
Other deferred credits and liabilities	1,167	816
Total deferred credits and other liabilities	33,979	33,926
Total Liabilities	100,359	94,967
Common Stockholders' Equity:
Common stock	5,417	5,279
Paid-in capital	13,673	11,950
Retained earnings (accumulated deficit)	11,538	10,929
Total common stockholders' equity	30,408	27,874
Total Liabilities and Stockholders' Equity	134,891	127,534
Commitments and Contingent Matters
Mississippi Power
Current Assets:
Cash and cash equivalents	59	61
Receivables —
Customer accounts	47	37
Unbilled revenues	47	34
Affiliated	82	29
Other accounts and notes	35	28
Fossil fuel for generation	44	28
Materials and supplies	80	70
Other regulatory assets	72	54
Other current assets	38	41
Total current assets	504	382
Property, Plant, and Equipment:
In service	5,254	5,106
Less: Accumulated depreciation	1,689	1,591
Plant in service, net of depreciation	3,565	3,515
Construction work in progress	208	127
Total property, plant, and equipment	3,773	3,642
Other Property and Investments:
Total other property and investments	167	179
Deferred Charges and Other Assets:
Deferred charges related to income taxes	30	31
Prepaid pension costs(a)	109	79
Regulatory assets – asset retirement obligations, deferred	239	232
Other regulatory assets, deferred	249	317
Accumulated deferred income taxes	107	118
Other deferred charges and assets	94	100
Total deferred charges and other assets	828	877
Total Assets	5,272	5,080
Current Liabilities:
Securities due within one year	1	1
Accounts payable —
Affiliated	121	81
Other	106	47
Accrued taxes	124	120
Accrued compensation	37	36
Asset retirement obligations	37	30
Other regulatory liabilities	43	59
Other current liabilities	85	65
Total current liabilities	554	439
Long-Term Debt	1,544	1,510
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	466	464
Deferred credits related to income taxes	253	269
Employee benefit obligations	69	88
Asset retirement obligations, deferred	142	160
Other cost of removal obligations	196	195
Other regulatory liabilities, deferred	96	64
Other deferred credits and liabilities	21	24
Total deferred credits and other liabilities	1,243	1,264
Total Liabilities	3,341	3,213
Common Stockholders' Equity:
Common stock	38	38
Paid-in capital	4,652	4,582
Retained earnings (accumulated deficit)	(2,759)	(2,753)
Total common stockholders' equity	1,931	1,867
Total Liabilities and Stockholders' Equity	5,272	5,080
Commitments and Contingent Matters

Balance Sheets - MPC (Parenthet

Balance Sheets - MPC (Parenthetical) - shares	Dec. 31, 2022	Dec. 31, 2021
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	1,500,000,000	1,500,000,000
Mississippi Power
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	1,000,000	1,000,000
Common stock, shares outstanding (in shares)	1,000,000	1,000,000

Statements of Common Stockhol_4

Statements of Common Stockholders' Equity - MPC - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Mississippi Power	Mississippi Power Common Stock	Mississippi Power Paid-In Capital	Mississippi Power Retained Earnings	Mississippi Power Accumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2019		1,054					1
Beginning balance at Dec. 31, 2019	$ 31,759	$ 5,257	$ 11,734	$ 10,877	$ (321)	$ 1,652	$ 38	$ 4,449	$ (2,832)	$ (3)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated Net Income	3,119					152			152
Return of capital to parent company						(74)		(74)
Capital contributions from parent company						86		86
Other comprehensive income (loss)	(75)				(75)	1				1
Cash dividends on common stock	(2,685)			(2,685)		(74)			(74)
Other	(12)		(10)		(1)	(1)		(1)
Ending balance (in shares) at Dec. 31, 2020		1,058					1
Ending balance at Dec. 31, 2020	32,234	$ 5,268	11,834	11,311	(395)	1,742	$ 38	4,460	(2,754)	(2)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated Net Income	2,393					159			159
Capital contributions from parent company						122		122
Other comprehensive income (loss)	158				158	1				1
Cash dividends on common stock	(2,777)			(2,777)		(157)			(157)
Other	(7)		(8)	2		0			1	(1)
Ending balance (in shares) at Dec. 31, 2021		1,061					1
Ending balance at Dec. 31, 2021	32,276	$ 5,279	11,950	10,929	(237)	1,867	$ 38	4,582	(2,753)	0
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Consolidated Net Income	3,524					164			164
Capital contributions from parent company						70		70
Other comprehensive income (loss)	71				71
Cash dividends on common stock	(2,907)			(2,907)		(170)			(170)
Other	(6)		9	(8)	(1)
Ending balance (in shares) at Dec. 31, 2022		1,090					1
Ending balance at Dec. 31, 2022	$ 34,532	$ 5,417	$ 13,673	$ 11,538	$ (167)	$ 1,931	$ 38	$ 4,652	$ (2,759)	$ 0

Consolidated Statements of In_2

Consolidated Statements of Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Revenues:
Total operating revenues	$ 29,279	$ 23,113	$ 20,375
Operating Expenses:
Other operations and maintenance	6,630	6,088	5,413
Depreciation and amortization	3,663	3,565	3,518
Taxes other than income taxes	1,411	1,290	1,234
Gain on dispositions, net	(57)	(186)	(65)
Total operating expenses	23,909	19,415	15,490
Operating Income	5,370	3,698	4,885
Other Income and (Expense):
Interest expense, net of amounts capitalized	(2,022)	(1,837)	(1,821)
Other income (expense), net	500	456	336
Total other income and (expense)	(1,147)	(1,122)	(1,389)
Earnings Before Income Taxes	4,223	2,576	3,496
Income taxes (benefit)	795	267	393
Net Income (Loss)	3,428	2,309	3,103
Net loss attributable to noncontrolling interests	(107)	(99)	(31)
Other revenues
Operating Revenues:
Total operating revenues	732	708	681
Operating Expenses:
Cost of sales	396	357	327
Fuel
Operating Expenses:
Cost of sales	6,835	4,010	2,967
Purchased power
Operating Expenses:
Cost of sales	1,593	978	799
Southern Power
Operating Revenues:
Total operating revenues	3,369	2,216	1,733
Operating Expenses:
Other operations and maintenance	482	423	353
Depreciation and amortization	516	517	494
Taxes other than income taxes	49	45	39
Loss on sales-type leases	1	40	0
Gain on dispositions, net	(2)	(41)	(39)
Total operating expenses	2,971	1,925	1,391
Operating Income	398	291	342
Other Income and (Expense):
Interest expense, net of amounts capitalized	(138)	(147)	(151)
Other income (expense), net	7	10	19
Total other income and (expense)	(131)	(137)	(132)
Earnings Before Income Taxes	267	154	210
Income taxes (benefit)	20	(13)	3
Net Income (Loss)	247	167	207
Net loss attributable to noncontrolling interests	(107)	(99)	(31)
Net Income (Loss) Attributable to Parent, Total	354	266	238
Southern Power | Wholesale revenues
Operating Revenues:
Total operating revenues	2,458	1,671	1,355
Southern Power | Other revenues
Operating Revenues:
Total operating revenues	36	30	14
Southern Power | Fuel
Operating Expenses:
Cost of sales	1,614	802	470
Southern Power | Purchased power
Operating Expenses:
Cost of sales	$ 311	$ 139	$ 74

Consolidated Statements of Co_3

Consolidated Statements of Comprehensive Income - SPC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net Income (Loss)	$ 3,428	$ 2,309	$ 3,103
Qualifying hedges:
Changes in fair value, net of tax	(60)	(49)	10
Reclassification adjustment for amounts included in net income, net of tax	73	96	(40)
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	48	98	(55)
Reclassification adjustment for amounts included in net income, net of tax	10	13	10
Current period change	71	158	(75)
Comprehensive loss attributable to noncontrolling interests	(107)	(99)	(31)
Comprehensive Income (Loss) Attributable to Parent	3,595	2,551	3,044
Southern Power
Net Income (Loss)	247	167	207
Qualifying hedges:
Changes in fair value, net of tax	(91)	(67)	33
Reclassification adjustment for amounts included in net income, net of tax	81	89	(65)
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	18	16	(12)
Reclassification adjustment for amounts included in net income, net of tax	2	2	2
Current period change	10	40	(42)
Comprehensive loss attributable to noncontrolling interests	(107)	(99)	(31)
Comprehensive Income (Loss) Attributable to Parent	$ 364	$ 306	$ 196

Consolidated Statements of Co_4

Consolidated Statements of Comprehensive Income - SPC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Qualifying hedges, change in fair value, tax	$ (19)	$ (16)	$ 3
Qualifying hedges, reclassification adjustment, tax	23	31	(13)
Pension and other postretirement benefit plans, gain (loss), tax	18	37	(17)
Reclassification adjustment for amounts included in net income, tax	3	5	3
Southern Power
Qualifying hedges, change in fair value, tax	(30)	(22)	12
Qualifying hedges, reclassification adjustment, tax	26	30	(22)
Pension and other postretirement benefit plans, gain (loss), tax	6	5	(4)
Reclassification adjustment for amounts included in net income, tax	$ 1	$ 1	$ 1

Consolidated Statements of Ca_3

Consolidated Statements of Cash Flows - SPC - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities:
Consolidated net income	$ 3,428	$ 2,309	$ 3,103
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	4,064	3,973	3,905
Deferred income taxes	670	(49)	(241)
Utilization of federal investment tax credits	88	288	341
Amortization of investment tax credits	(83)	(84)	(84)
Gain on dispositions, net	(42)	(176)	(66)
Other, net	17	87	(75)
Changes in certain current assets and liabilities —
-Receivables	(769)	(81)	(222)
-Other current assets	(288)	(270)	(132)
-Other current liabilities	153	(204)	173
Net cash provided from operating activities	6,302	6,169	6,696
Investing Activities:
Property additions	(7,923)	(7,586)	(7,522)
Proceeds from dispositions	275	917	1,049
Payments pursuant to LTSAs	(190)	(188)	(211)
Other investing activities	70	(49)	21
Net cash used for investing activities	(8,430)	(7,353)	(7,030)
Financing Activities:
Increase (decrease) in notes payable, net		530
Increase (decrease) in notes payable, net	(337)		(1,096)
Redemptions and repurchases —
Short-term borrowings	(1,150)	(25)	(840)
Capital contributions from noncontrolling interests	73	501	363
Distributions to noncontrolling interests	(259)	(351)	(271)
Payment of common stock dividends	(2,907)	(2,777)	(2,685)
Other financing activities	(218)	(266)	(325)
Net cash provided from (used for) financing activities	2,336	1,945	(576)
Net Change in Cash, Cash Equivalents, and Restricted Cash	208	761	(910)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	1,829	1,068	1,978
Cash, Cash Equivalents, and Restricted Cash at End of Year	2,037	1,829	1,068
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	1,758	1,718	1,683
Income taxes, net	146	93	64
Noncash transactions —
Accrued property additions at year-end	1,024	866	989
Contributions from noncontrolling interests	15	89	12
Contributions of wind turbine equipment	0	82	17
Southern Power
Operating Activities:
Consolidated net income	247	167	207
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	543	542	519
Deferred income taxes	9	55	(25)
Utilization of federal investment tax credits	49	288	340
Amortization of investment tax credits	(58)	(58)	(59)
Income taxes receivable, non-current	1	5	(20)
Gain on dispositions, net	(2)	(41)	(39)
Loss on sales-type leases	1	40	0
Other, net	17	(6)	(5)
Changes in certain current assets and liabilities —
-Receivables	(82)	(44)	(4)
-Prepaid income taxes	22	(16)	20
-Other current assets	(11)	(14)	(30)
-Other current liabilities	79	33	(3)
Net cash provided from operating activities	815	951	901
Investing Activities:
Acquisitions, net of cash acquired	0	(345)	(81)
Property additions	(100)	(396)	(223)
Change in construction payables	(69)	(15)	31
Proceeds from dispositions	48	24	666
Payments pursuant to LTSAs	(71)	(82)	(76)
Other investing activities	(2)	11	57
Net cash used for investing activities	(194)	(803)	374
Financing Activities:
Increase (decrease) in notes payable, net	10	36
Increase (decrease) in notes payable, net			(274)
Proceeds —
Senior notes	0	400	0
Redemptions and repurchases —
Senior notes	(677)	(300)	(825)
Short-term borrowings	0	0	(100)
Capital contributions from parent company	430	8	6
Return of capital to parent company	0	(271)	0
Capital contributions from noncontrolling interests	73	501	363
Distributions to noncontrolling interests	(259)	(351)	(271)
Purchase of membership interests from noncontrolling interests	0	0	(60)
Payment of common stock dividends	(198)	(204)	(201)
Other financing activities	(2)	(14)	(10)
Net cash provided from (used for) financing activities	(623)	(195)	(1,372)
Net Change in Cash, Cash Equivalents, and Restricted Cash	(2)	(47)	(97)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	135	182	279
Cash, Cash Equivalents, and Restricted Cash at End of Year	133	135	182
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	142	140	147
Income taxes, net	(15)	(275)	(283)
Noncash transactions —
Accrued property additions at year-end	24	72	89
Contributions from noncontrolling interests	15	89	12
Contributions of wind turbine equipment	$ 0	$ 82	$ 17

Consolidated Statements of Ca_4

Consolidated Statements of Cash Flows - SPC (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net cash paid for capitalized interest	$ 103	$ 92	$ 81
Southern Power
Net cash paid for capitalized interest	$ 0	$ 6	$ 11

Consolidated Balance Sheets -_3

Consolidated Balance Sheets - SPC - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 1,917	$ 1,798
Receivables —
Customer accounts	2,138	1,806
Other accounts and notes	637	523
Materials and supplies	1,664	1,543
Other current assets	344	231
Total current assets	10,416	8,965
Property, Plant, and Equipment:
In service	117,529	115,592
Less: Accumulated depreciation	35,297	34,079
Plant in service, net of depreciation	82,232	81,513
Construction work in progress	10,896	8,771
Total property, plant, and equipment	94,570	91,108
Other Property and Investments:
Equity investments in unconsolidated subsidiaries	1,443	1,282
Total other property and investments	9,757	10,202
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,531	1,701
Other deferred charges and assets	1,485	1,366
Total deferred charges and other assets	20,148	17,259
Total Assets	134,891	127,534
Current Liabilities:
Securities due within one year	4,285	2,157
Notes payable	2,609	1,440
Accounts payable —
Accrued interest	614	533
Other current liabilities	965	872
Total current liabilities	15,724	10,921
Long-Term Debt	50,656	50,120
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	10,036	8,862
Accumulated deferred ITCs	2,133	2,216
Operating lease obligations, deferred	1,388	1,503
Other deferred credits and liabilities	1,167	816
Total deferred credits and other liabilities	33,979	33,926
Total Liabilities	100,359	94,967
Common Stockholders' Equity:
Common stock	5,417	5,279
Paid-in capital	13,673	11,950
Retained earnings (accumulated deficit)	11,538	10,929
Accumulated other comprehensive loss	(167)	(237)
Total common stockholders' equity	30,408	27,874
Noncontrolling Interests	4,124	4,402
Total Stockholders' Equity (See accompanying statements)	34,532	32,276
Total Liabilities and Stockholders' Equity	134,891	127,534
Commitments and Contingent Matters
Southern Power
Current Assets:
Cash and cash equivalents	131	107
Receivables —
Customer accounts	226	139
Affiliated	51	51
Other accounts and notes	70	29
Materials and supplies	88	106
Prepaid income taxes	5	27
Other current assets	50	46
Total current assets	621	505
Property, Plant, and Equipment:
In service	14,658	14,585
Less: Accumulated depreciation	3,661	3,241
Plant in service, net of depreciation	10,997	11,344
Construction work in progress	41	45
Total property, plant, and equipment	11,038	11,389
Other Property and Investments:
Intangible assets, net of amortization of $129 and $109, respectively	263	282
Equity investments in unconsolidated subsidiaries	49	86
Net investment in sales-type leases	154	161
Total other property and investments	466	529
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	489	479
Prepaid LTSAs	193	210
Income taxes receivable, non-current	19	20
Other deferred charges and assets	255	258
Total deferred charges and other assets	956	967
Total Assets	13,081	13,390
Current Liabilities:
Securities due within one year	290	679
Notes payable	225	211
Accounts payable —
Affiliated	139	92
Other	67	85
Accrued taxes	24	14
Accrued interest	28	32
Other current liabilities	111	140
Total current liabilities	884	1,253
Long-Term Debt	2,689	3,009
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	279	215
Accumulated deferred ITCs	1,556	1,614
Operating lease obligations, deferred	514	497
Other deferred credits and liabilities	243	204
Total deferred credits and other liabilities	2,592	2,530
Total Liabilities	6,165	6,792
Common Stockholders' Equity:
Common stock	0	0
Paid-in capital	1,069	638
Retained earnings (accumulated deficit)	1,741	1,585
Accumulated other comprehensive loss	(18)	(27)
Total common stockholders' equity	2,792	2,196
Noncontrolling Interests	4,124	4,402
Total Stockholders' Equity (See accompanying statements)	6,916	6,598
Total Liabilities and Stockholders' Equity	13,081	13,390
Commitments and Contingent Matters

Consolidated Balance Sheets -_4

Consolidated Balance Sheets - SPC (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Other intangible assets, amortization	$ 340	$ 307
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	1,500,000,000	1,500,000,000
Southern Power
Other intangible assets, amortization	$ 129	$ 109
Cumulative preferred stock
Par value (in dollars per share)	$ 0.01	$ 0.01
Common Stockholders' Equity:
Common stock, shares authorized (in shares)	1,000,000	1,000,000
Common stock, shares outstanding (in shares)	1,000	1,000

Consolidated Statements of St_3

Consolidated Statements of Stockholders' Equity - SPC - USD ($) $ in Millions	Total	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests	Southern Power		Southern Power Total Common Stockholder's Equity		Southern Power Paid-In Capital		Southern Power Retained Earnings	Southern Power Accumulated Other Comprehensive Income (Loss)	Southern Power Noncontrolling Interests
Beginning balance at Dec. 31, 2019	$ 31,759	$ 11,734	$ 10,877	$ (321)	$ 4,254	$ 6,622		$ 2,368		$ 909		$ 1,485	$ (26)	$ 4,254
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	3,103					207		238				238		(31)
Capital contributions from parent company						2		2		2
Other comprehensive income (loss)	(75)			(75)		(42)		(42)					(42)
Cash dividends on common stock	(2,685)		(2,685)			(201)		(201)				(201)
Contributions from noncontrolling interests	307				307	307								307
Distributions to noncontrolling interests	(271)				(271)	(271)								(271)
Purchase of membership interests from noncontrolling interests		5				60				5
Purchase of membership interests from noncontrolling interests	(60)				(65)	60		(5)						65
Sale of noncontrolling interests	65	(2)			67	65	[1]	(2)	[1]	(2)	[1]			67	[1]
Other	(12)	(10)		(1)	1	2		1					1	1
Ending balance at Dec. 31, 2020	32,234	11,834	11,311	(395)	4,262	6,631		2,369		914		1,522	(67)	4,262
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	2,309					167		266				266		(99)
Return of capital to parent company						(271)		(271)		(271)
Capital contributions from parent company						10		10		10
Other comprehensive income (loss)	158			158		40		40					40
Cash dividends on common stock	(2,777)		(2,777)			(204)		(204)				(204)
Contributions from noncontrolling interests	590				590	590								590
Distributions to noncontrolling interests	(351)				(351)	(351)								(351)
Purchase of membership interests from noncontrolling interests						0
Other	(7)	(8)	2			(14)		(14)		15		(1)		0
Ending balance at Dec. 31, 2021	32,276	11,950	10,929	(237)	4,402	6,598		2,196		638		1,585	(27)	4,402
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	3,428					247		354				354		(107)
Capital contributions from parent company						431		431		431
Other comprehensive income (loss)	71			71		10		10					10
Cash dividends on common stock	(2,907)		(2,907)			(198)		(198)				(198)
Contributions from noncontrolling interests	88				88	88								88
Distributions to noncontrolling interests	(259)				(259)	(259)								(259)
Purchase of membership interests from noncontrolling interests						0
Other	(6)	9	(8)	(1)		(1)		(1)					(1)	0
Ending balance at Dec. 31, 2022	$ 34,532	$ 13,673	$ 11,538	$ (167)	$ 4,124	$ 6,916		$ 2,792		$ 1,069		$ 1,741	$ (18)	$ 4,124
[1]See Note 15 under "Southern Power" for additional information.

Consolidated Statements of In_3

Consolidated Statements of Income - GAS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Revenues:
Total operating revenues	$ 29,279	$ 23,113	$ 20,375
Operating Expenses:
Other operations and maintenance	6,630	6,088	5,413
Depreciation and amortization	3,663	3,565	3,518
Taxes other than income taxes	1,411	1,290	1,234
Impairment charges	251	2	0
Gain on dispositions, net	(57)	(186)	(65)
Total operating expenses	23,909	19,415	15,490
Operating income (loss)	5,370	3,698	4,885
Other Income and (Expense):
Earnings from equity method investments	151	76	153
Interest expense, net of amounts capitalized	(2,022)	(1,837)	(1,821)
Other income (expense), net	500	456	336
Total other income and (expense)	(1,147)	(1,122)	(1,389)
Earnings Before Income Taxes	4,223	2,576	3,496
Income taxes (benefit)	795	267	393
Consolidated Net Income	3,524	2,393	3,119
Southern Company Gas
Operating Revenues:
Total operating revenues	5,962	4,380	3,434
Operating Expenses:
Cost of sales	3,004	1,619	972
Other operations and maintenance	1,176	1,072	966
Depreciation and amortization	559	536	500
Taxes other than income taxes	282	225	206
Impairment charges	131	0	0
Gain on dispositions, net	(4)	(127)	(22)
Total operating expenses	5,148	3,325	2,622
Operating income (loss)	814	1,055	812
Other Income and (Expense):
Earnings from equity method investments	148	50	141
Interest expense, net of amounts capitalized	(263)	(238)	(231)
Other income (expense), net	53	(53)	41
Total other income and (expense)	(62)	(241)	(49)
Earnings Before Income Taxes	752	814	763
Income taxes (benefit)	180	275	173
Consolidated Net Income	$ 572	$ 539	$ 590

Consolidated Statements of In_4

Consolidated Statements of Income - GAS (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Southern Company Gas
Excise taxes collected	$ 162	$ 122	$ 107

Consolidated Statements of Co_5

Consolidated Statements of Comprehensive Income - GAS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net Income (Loss)	$ 3,428	$ 2,309	$ 3,103
Qualifying hedges:
Changes in fair value, net of tax	(60)	(49)	10
Reclassification adjustment for amounts included in net income, net of tax	73	96	(40)
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	48	98	(55)
Current period change	71	158	(75)
Comprehensive Income (Loss) Attributable to Parent	3,595	2,551	3,044
Southern Company Gas
Net Income (Loss)	572	539	590
Qualifying hedges:
Changes in fair value, net of tax	13	17	(21)
Reclassification adjustment for amounts included in net income, net of tax	(24)	(11)	7
Pension and other postretirement benefit plans:
Benefit plan net gain (loss), net of tax	18	40	(15)
Current period change	7	46	(29)
Comprehensive Income (Loss) Attributable to Parent	$ 579	$ 585	$ 561

Consolidated Statements of Co_6

Consolidated Statements of Comprehensive Income - GAS (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Qualifying hedges, change in fair value, tax	$ (19)	$ (16)	$ 3
Qualifying hedges, reclassification adjustment, tax	23	31	(13)
Pension and other postretirement benefit plans, gain (loss), tax	18	37	(17)
Southern Company Gas
Qualifying hedges, change in fair value, tax	5	5	(8)
Qualifying hedges, reclassification adjustment, tax	(9)	(5)	3
Pension and other postretirement benefit plans, gain (loss), tax	$ 8	$ 17	$ (3)

Consolidated Statements of Ca_5

Consolidated Statements of Cash Flows - GAS - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating Activities:
Consolidated net income	$ 3,428	$ 2,309	$ 3,103
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	4,064	3,973	3,905
Deferred income taxes	670	(49)	(241)
Gain on dispositions, net	(42)	(176)	(66)
Natural gas cost under recovery – long-term	207	(207)	0
Other, net	17	87	(75)
Changes in certain current assets and liabilities —
-Receivables	(769)	(81)	(222)
-Natural gas cost under recovery	158	(266)	0
-Other current assets	(288)	(270)	(132)
-Accounts payable	1,021	(8)	(27)
-Other current liabilities	153	(204)	173
Net cash provided from operating activities	6,302	6,169	6,696
Investing Activities:
Property additions	(7,923)	(7,586)	(7,522)
Cost of removal, net of salvage	(649)	(442)	(361)
Proceeds from dispositions	275	917	1,049
Other investing activities	70	(49)	21
Net cash used for investing activities	(8,430)	(7,353)	(7,030)
Financing Activities:
Increase (decrease) in notes payable, net		530
Increase (decrease) in notes payable, net	(337)		(1,096)
Proceeds —
Short-term borrowings	2,650	325	615
Redemptions and repurchases —
Short-term borrowings	(1,150)	(25)	(840)
Payment of common stock dividends	(2,907)	(2,777)	(2,685)
Other financing activities	(218)	(266)	(325)
Net cash provided from (used for) financing activities	2,336	1,945	(576)
Net Change in Cash, Cash Equivalents, and Restricted Cash	208	761	(910)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	1,829	1,068	1,978
Cash, Cash Equivalents, and Restricted Cash at End of Year	2,037	1,829	1,068
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	1,758	1,718	1,683
Income taxes, net	146	93	64
Noncash transactions —
Accrued property additions at year-end	1,024	866	989
Southern Company Gas
Operating Activities:
Consolidated net income	572	539	590
Adjustments to reconcile consolidated net income to net cash provided from operating activities —
Depreciation and amortization, total	558	536	500
Deferred income taxes	17	259	56
Impairment charges	131	84	0
Gain on dispositions, net	(4)	(127)	(22)
Mark-to-market adjustments	12	194	61
Natural gas cost under recovery – long-term	207	(207)	0
Other, net	(32)	(30)	(29)
Changes in certain current assets and liabilities —
-Receivables	(345)	(143)	(93)
-Natural gas for sale, net of temporary LIFO liquidation	(77)	8	18
-Prepaid income taxes	19	(82)	19
-Natural gas cost under recovery	158	(266)	0
-Other current assets	(6)	(116)	(10)
-Accounts payable	299	40	103
-Other current liabilities	10	(26)	14
Net cash provided from operating activities	1,519	663	1,207
Investing Activities:
Property additions	(1,533)	(1,421)	(1,471)
Cost of removal, net of salvage	(112)	(106)	(100)
Change in construction payables, net	65	(29)	20
Investments in unconsolidated subsidiaries	(165)	(5)	(79)
Proceeds from dispositions	150	150	211
Other investing activities	15	32	2
Net cash used for investing activities	(1,580)	(1,379)	(1,417)
Financing Activities:
Increase (decrease) in notes payable, net		585
Increase (decrease) in notes payable, net	(341)		(326)
Proceeds —
Senior notes	500	450	500
Short-term borrowings	50	300	0
First mortgage bonds	175	200	325
Other long-term debt	22	0	0
Redemptions and repurchases —
Senior notes	0	(300)	0
Medium-term notes	(46)	(30)	0
Short-term borrowings	(150)	0	0
Capital contributions from parent company	406	72	216
Payment of common stock dividends	(519)	(530)	(533)
Other financing activities	(1)	(2)	(2)
Net cash provided from (used for) financing activities	96	745	180
Net Change in Cash, Cash Equivalents, and Restricted Cash	35	29	(30)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Year	48	19	49
Cash, Cash Equivalents, and Restricted Cash at End of Year	83	48	19
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	258	244	232
Income taxes, net	208	57	25
Noncash transactions —
Accrued property additions at year-end	$ 177	$ 113	$ 142

Consolidated Statements of Ca_6

Consolidated Statements of Cash Flows - GAS (Parenthetical) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Net cash paid for capitalized interest	$ 103	$ 92	$ 81
Southern Company Gas
Net cash paid for capitalized interest	$ 10	$ 8	$ 7

Consolidated Balance Sheets - G

Consolidated Balance Sheets - GAS - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 1,917	$ 1,798
Receivables —
Customer accounts	2,138	1,806
Unbilled revenues	1,012	711
Other accounts and notes	637	523
Accumulated provision for uncollectible accounts	(71)	(78)
Natural gas for sale	438	362
Prepaid expenses	347	330
Natural gas cost under recovery	108	266
Other regulatory assets	860	653
Other current assets	344	231
Total current assets	10,416	8,965
Property, Plant, and Equipment:
In service	117,529	115,592
Less: Accumulated depreciation	35,297	34,079
Plant in service, net of depreciation	82,232	81,513
Construction work in progress	10,896	8,771
Total property, plant, and equipment	94,570	91,108
Other Property and Investments:
Goodwill	5,161	5,280
Equity investments in unconsolidated subsidiaries	1,443	1,282
Other intangible assets, net of amortization	406	445
Miscellaneous property and investments	602	653
Total other property and investments	9,757	10,202
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,531	1,701
Prepaid pension costs	2,290	1,657
Other regulatory assets, deferred	5,918	5,577
Other deferred charges and assets	1,485	1,366
Total deferred charges and other assets	20,148	17,259
Total Assets	134,891	127,534
Current Liabilities:
Securities due within one year	4,285	2,157
Notes payable	2,609	1,440
Accounts payable —
Customer deposits	502	479
Accrued compensation	1,127	1,070
Other regulatory liabilities	382	563
Other current liabilities	965	872
Total current liabilities	15,724	10,921
Long-Term Debt	50,656	50,120
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	10,036	8,862
Deferred credits related to income taxes	5,235	5,401
Employee benefit obligations	1,238	1,550
Operating lease obligations, deferred	1,388	1,503
Other cost of removal obligations	1,903	2,103
Other deferred credits and liabilities	1,167	816
Total deferred credits and other liabilities	33,979	33,926
Total Liabilities	100,359	94,967
Common Stockholders' Equity:
Common stock	5,417	5,279
Retained earnings (accumulated deficit)	11,538	10,929
Accumulated other comprehensive loss	(167)	(237)
Total Stockholders' Equity (See accompanying statements)	34,532	32,276
Total Liabilities and Stockholders' Equity	134,891	127,534
Commitments and Contingent Matters
Southern Company Gas
Current Assets:
Cash and cash equivalents	81	45
Receivables —
Customer accounts	616	462
Unbilled revenues	453	278
Other accounts and notes	76	49
Accumulated provision for uncollectible accounts	(50)	(39)
Natural gas for sale	438	362
Prepaid expenses	93	114
Natural gas cost under recovery	108	266
Other regulatory assets	119	136
Other current assets	104	82
Total current assets	2,038	1,755
Property, Plant, and Equipment:
In service	19,723	18,880
Less: Accumulated depreciation	5,276	5,067
Plant in service, net of depreciation	14,447	13,813
Construction work in progress	909	684
Total property, plant, and equipment	15,356	14,497
Other Property and Investments:
Goodwill	5,015	5,015
Equity investments in unconsolidated subsidiaries	1,276	1,173
Other intangible assets, net of amortization	26	37
Miscellaneous property and investments	28	19
Total other property and investments	6,345	6,244
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	57	70
Prepaid pension costs	183	175
Other regulatory assets, deferred	497	689
Other deferred charges and assets	145	130
Total deferred charges and other assets	882	1,064
Total Assets	24,621	23,560
Current Liabilities:
Securities due within one year	400	47
Notes payable	768	1,209
Accounts payable —
Affiliated	104	58
Other	701	361
Customer deposits	125	95
Accrued taxes	77	124
Accrued compensation	105	110
Other regulatory liabilities	36	8
Other current liabilities	254	214
Total current liabilities	2,570	2,226
Long-Term Debt	7,042	6,855
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	1,560	1,555
Deferred credits related to income taxes	788	816
Employee benefit obligations	120	176
Operating lease obligations, deferred	51	59
Other cost of removal obligations	1,707	1,683
Accrued environmental remediation	207	197
Other deferred credits and liabilities	179	77
Total deferred credits and other liabilities	4,612	4,563
Total Liabilities	14,224	13,644
Common Stockholders' Equity:
Common stock	10,445	10,024
Retained earnings (accumulated deficit)	(79)	(132)
Accumulated other comprehensive loss	31	24
Total Stockholders' Equity (See accompanying statements)	10,397	9,916
Total Liabilities and Stockholders' Equity	24,621	23,560
Commitments and Contingent Matters

Consolidated Balance Sheets -_5

Consolidated Balance Sheets - GAS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Other intangible assets, amortization	$ 340	$ 307
Common Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 5	$ 5
Common stock, shares authorized (in shares)	1,500,000,000	1,500,000,000
Southern Company Gas
Other intangible assets, amortization	$ 156	$ 145
Common Stockholders' Equity:
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	100,000,000	100,000,000
Common stock, shares outstanding (in shares)	100	100

Consolidated Statements of Comm

Consolidated Statements of Common Stockholders' Equity - GAS - USD ($) $ in Millions	Total	Paid-In Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Southern Company Gas	Southern Company Gas Paid-In Capital	Southern Company Gas Retained Earnings	Southern Company Gas Accumulated Other Comprehensive Income (Loss)
Beginning balance at Dec. 31, 2019	$ 31,759	$ 11,734	$ 10,877	$ (321)	$ 9,506	$ 9,697	$ (198)	$ 7
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	3,103				590		590
Capital contributions from parent company					233	233
Other comprehensive income (loss)	(75)			(75)	(29)			(29)
Cash dividends on common stock	(2,685)		(2,685)		(533)		(533)
Ending balance at Dec. 31, 2020	32,234	11,834	11,311	(395)	9,767	9,930	(141)	(22)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	2,309				539		539
Capital contributions from parent company					94	94
Other comprehensive income (loss)	158			158	46			46
Cash dividends on common stock	(2,777)		(2,777)		(530)		(530)
Ending balance at Dec. 31, 2021	32,276	11,950	10,929	(237)	9,916	10,024	(132)	24
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	3,428				572		572
Capital contributions from parent company					421	421
Other comprehensive income (loss)	71			71	7			7
Cash dividends on common stock	(2,907)		(2,907)		(519)		(519)
Ending balance at Dec. 31, 2022	$ 34,532	$ 13,673	$ 11,538	$ (167)	$ 10,397	$ 10,445	$ (79)	$ 31

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES General Southern Company is the parent company of three traditional electric operating companies, as well as Southern Power, Southern Company Gas, SCS, Southern Linc, Southern Holdings, Southern Nuclear, PowerSecure, and other direct and indirect subsidiaries. The traditional electric operating companies – Alabama Power, Georgia Power, and Mississippi Power – are vertically integrated utilities providing electric service in three Southeastern states. Southern Power develops, constructs, acquires, owns, and manages power generation assets, including renewable energy projects, and sells electricity at market-based rates in the wholesale market. Southern Company Gas distributes natural gas through natural gas distribution utilities, including Nicor Gas (Illinois), Atlanta Gas Light (Georgia), Virginia Natural Gas, and Chattanooga Gas (Tennessee). Southern Company Gas is also involved in several other complementary businesses including gas pipeline investments and gas marketing services. Prior to the sale of Sequent on July 1, 2021, these businesses also included wholesale gas services. SCS, the system service company, provides, at cost, specialized services to Southern Company and its subsidiary companies. Southern Linc provides digital wireless communications for use by Southern Company and its subsidiary companies and also markets these services to the public and provides fiber optics services within the Southeast. Southern Holdings is an intermediate holding company subsidiary. Southern Nuclear operates and provides services to the Southern Company system's nuclear power plants, including Alabama Power's Plant Farley and Georgia Power's Plant Hatch and Plant Vogtle Units 1 and 2, and is currently managing construction and start-up of Plant Vogtle Units 3 and 4, which are co-owned by Georgia Power. PowerSecure develops distributed energy and resilience solutions and deploys microgrids for commercial, industrial, governmental, and utility customers. See Note 15 for information regarding the sale of Sequent. The Registrants' financial statements reflect investments in subsidiaries on a consolidated basis. Intercompany transactions have been eliminated in consolidation. The equity method is used for investments in entities in which a Registrant has significant influence but does not have control and for VIEs where a Registrant has an equity investment but is not the primary beneficiary. Southern Power has controlling ownership in certain legal entities for which the contractual provisions represent profit-sharing arrangements because the allocations of cash distributions and tax benefits are not based on fixed ownership percentages. For these arrangements, the noncontrolling interest is accounted for under a balance sheet approach utilizing the HLBV method. The HLBV method calculates each partner's share of income based on the change in net equity the partner can legally claim in a HLBV at the end of the period compared to the beginning of the period. See "Variable Interest Entities" herein and Note 7 for additional information. The traditional electric operating companies, Southern Power, certain subsidiaries of Southern Company Gas, and certain other subsidiaries are subject to regulation by the FERC, and the traditional electric operating companies and the natural gas distribution utilities are also subject to regulation by their respective state PSCs or other applicable state regulatory agencies. As such, the respective financial statements of the applicable Registrants reflect the effects of rate regulation in accordance with GAAP and comply with the accounting policies and practices prescribed by relevant state PSCs or other applicable state regulatory agencies. The preparation of financial statements in conformity with GAAP requires the use of estimates, and the actual results may differ from those estimates. Certain prior years' data presented in the financial statements have been reclassified to conform to the current year presentation. These reclassifications had no impact on the Registrants' results of operations, financial position, or cash flows. Recently Adopted Accounting Standards In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (ASU 2020-04) providing temporary guidance to ease the potential burden in accounting for reference rate reform primarily resulting from the discontinuation of LIBOR, which began phasing out on December 31, 2021. The discontinuation date of the overnight 1-, 3-, 6-, and 12-month tenors of LIBOR is June 30, 2023, which is beyond the original effective date of ASU 2020-04; therefore, on December 21, 2022, the FASB issued ASU 2022-06, Reference Rate Reform (Topic 848): Deferral of the Sunset Date of Topic 848 (ASU 2022-06) to defer the sunset date of ASU 2020-04 from December 31, 2022 to December 31, 2024. The amendments are elective and apply to all entities that have contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued. The guidance (i) simplifies accounting analyses under current GAAP for contract modifications; (ii) simplifies the assessment of hedge effectiveness and allows hedging relationships affected by reference rate reform to continue; and (iii) allows a one-time election to sell or transfer debt securities classified as held to maturity that reference a rate affected by reference rate reform. An entity may elect to apply the amendments prospectively from March 12, 2020 through December 31, 2024 by accounting topic. The Registrants have elected to apply the amendments to modifications of debt and derivative arrangements that meet the scope of ASU 2020-04 and ASU 2022-06. The Registrants currently reference LIBOR for certain debt and hedging arrangements. In addition, certain provisions in PPAs at Southern Power include references to LIBOR. Contract language has been, or is expected to be, incorporated into each of these agreements to address the transition to an alternative rate for agreements that will be in place at the transition date. No material impacts are expected from modifications to the arrangements and effective hedging relationships are expected to continue. See Note 14 under "Interest Rate Derivatives" for additional information. Affiliate Transactions The traditional electric operating companies, Southern Power, and Southern Company Gas have agreements with SCS under which certain of the following services are rendered to them at direct or allocated cost: general executive and advisory, general and design engineering, operations, purchasing, accounting, finance, treasury, legal, tax, information technology, marketing, auditing, insurance and pension administration, human resources, systems and procedures, digital wireless communications, cellular tower space, and other services with respect to business and operations, construction management, and Southern Company power pool transactions. These costs are primarily included in other operations and maintenance expenses or capitalized to property, plant, and equipment. Costs for these services from SCS in 2022, 2021, and 2020 were as follows: Alabama Georgia Mississippi Southern Southern Company Gas (in millions) 2022 $ 549 $ 762 $ 115 $ 86 $ 262 2021 504 663 120 89 239 2020 478 639 149 87 237 Alabama Power and Georgia Power also have agreements with Southern Nuclear under which Southern Nuclear renders the following nuclear-related services at cost: general executive and advisory services; general operations, management, and technical services; administrative services including procurement, accounting, employee relations, systems, and procedures services; strategic planning and budgeting services; other services with respect to business and operations; and, for Georgia Power, construction management. These costs are primarily included in other operations and maintenance expenses or capitalized to property, plant, and equipment. Costs for these services in 2022, 2021, and 2020 amounted to $267 million, $258 million, and $262 million, respectively, for Alabama Power and $895 million, $906 million, and $883 million, respectively, for Georgia Power. See Note 2 under "Georgia Power – Nuclear Construction" for additional information regarding Southern Nuclear's construction management of Plant Vogtle Units 3 and 4 for Georgia Power. Cost allocation methodologies used by SCS and Southern Nuclear prior to the repeal of the Public Utility Holding Company Act of 1935, as amended, were approved by the SEC. Subsequently, additional cost allocation methodologies have been reported to the FERC and management believes they are reasonable. The FERC permits services to be rendered at cost by system service companies. Alabama Power's and Georgia Power's power purchases from affiliates through the Southern Company power pool are included in purchased power, affiliates on their respective statements of income. Mississippi Power's and Southern Power's power purchases from affiliates through the Southern Company power pool are included in purchased power on their respective statements of income and were as follows: Mississippi Southern (in millions) 2022 $ 4 $ 29 2021 9 15 2020 4 8 Georgia Power has entered into several PPAs with Southern Power for capacity and energy. Georgia Power's total expenses associated with these PPAs were $151 million, $132 million, and $141 million in 2022, 2021, and 2020, respectively. Southern Power's total revenues from all PPAs with Georgia Power, included in wholesale revenue affiliates on Southern Power's consolidated statements of income, were $154 million, $139 million, and $139 million for 2022, 2021, and 2020, respectively. Included within these revenues were affiliate PPAs accounted for as operating leases, which totaled $116 million, $112 million, and $115 million for 2022, 2021, and 2020, respectively. See Note 9 for additional information. SCS (as agent for Alabama Power, Georgia Power, and Southern Power) and Southern Company Gas have long-term interstate natural gas transportation agreements with SNG that are governed by the terms and conditions of SNG's natural gas tariff and are subject to FERC regulation. See Note 7 under "Southern Company Gas – Equity Method Investments" for additional information. Transportation costs under these agreements in 2022, 2021, and 2020 were as follows: Alabama Georgia Southern Southern Company Gas (in millions) 2022 $ 18 $ 99 $ 37 $ 27 2021 14 108 31 29 2020 15 108 29 29 SCS, as agent for the traditional electric operating companies and Southern Power, has agreements with certain subsidiaries of Southern Company Gas to purchase natural gas. Natural gas purchases made under these agreements were immaterial for Alabama Power, Georgia Power, and Mississippi Power for all periods presented and immaterial, $18 million, and $26 million for Southern Power in 2022, 2021, and 2020, respectively. Alabama Power and Mississippi Power jointly own Plant Greene County. The companies have an agreement under which Alabama Power operates Plant Greene County and Mississippi Power reimburses Alabama Power for its proportionate share of non-fuel operations and maintenance expenses, which totaled $6 million, $10 million, and $9 million in 2022, 2021, and 2020, respectively. See Note 5 under "Joint Ownership Agreements" for additional information. Alabama Power, Georgia Power, and Mississippi Power each have agreements with PowerSecure for equipment purchases and/or services related to utility infrastructure construction, distributed energy, and energy efficiency projects. Costs under these agreements were immaterial for all periods presented. In 2022, Southern Company Gas entered into a $70 million contract with the U.S. General Services Administration to increase energy efficiency at certain federal buildings across Georgia, with completion expected to occur in 2024. Southern Company Gas engaged PowerSecure to provide the majority of the construction services under the contract. During 2022, Southern Company Gas paid $10 million to PowerSecure related to this agreement. See Note 7 under "SEGCO" for information regarding Alabama Power's and Georgia Power's equity method investment in SEGCO and related affiliate purchased power costs, as well as Alabama Power's gas pipeline ownership agreement with SEGCO. Southern Power has several agreements with SCS for transmission services, which are billed to Southern Power based on the Southern Company Open Access Transmission Tariff as filed with the FERC. Transmission services purchased by Southern Power from SCS totaled $39 million, $28 million, and $15 million for 2022, 2021, and 2020, respectively, and were charged to other operations and maintenance expenses in Southern Power's consolidated statements of income. The traditional electric operating companies and Southern Power may jointly enter into various types of wholesale energy, natural gas, and certain other contracts, either directly or through SCS as agent. Each participating company may be jointly and severally liable for the obligations incurred under these agreements. See Note 14 under "Contingent Features" for additional information. Southern Power and the traditional electric operating companies generally settle amounts related to the above transactions on a monthly basis in the month following the performance of such services or the purchase or sale of electricity. See "Revenues – Southern Power" herein for additional information. The traditional electric operating companies, Southern Power, and Southern Company Gas provide incidental services to and receive such services from other Southern Company subsidiaries which are generally minor in duration and amount. Except as described herein, the traditional electric operating companies, Southern Power, and Southern Company Gas neither provided nor received any material services to or from affiliates in any year presented. Regulatory Assets and Liabilities The traditional electric operating companies and the natural gas distribution utilities are subject to accounting requirements for the effects of rate regulation. Regulatory assets represent probable future revenues associated with certain costs that are expected to be recovered from customers through the ratemaking process. Regulatory liabilities represent costs recovered that are expected to be incurred in the future or probable future reductions in revenues associated with amounts that are expected to be credited to customers through the ratemaking process. In the event that a portion of a traditional electric operating company's or a natural gas distribution utility's operations is no longer subject to applicable accounting rules for rate regulation, such company would be required to write off to income or reclassify to AOCI related regulatory assets and liabilities that are not specifically recoverable through regulated rates. In addition, the Revenues The Registrants generate revenues from a variety of sources which are accounted for under various revenue accounting guidance, including revenue from contracts with customers, lease, derivative, and regulatory accounting. See Notes 4, 9, and 14 for additional information. Traditional Electric Operating Companies The majority of the revenues of the traditional electric operating companies are generated from contracts with retail electric customers. These revenues, generated from the integrated service to deliver electricity when and if called upon by the customer, are recognized as a single performance obligation satisfied over time, at a tariff rate, and as electricity is delivered to the customer during the month. Unbilled revenues related to retail sales are accrued at the end of each fiscal period. Retail rates may include provisions to adjust revenues for fluctuations in fuel costs, fuel hedging, the energy component of purchased power costs, and certain other costs. Revenues are adjusted for differences between these actual costs and amounts billed in current regulated rates. Under or over recovered regulatory clause revenues are recorded in the balance sheets and are recovered from or returned to customers, respectively, through adjustments to the billing factors. See Note 2 for additional information regarding regulatory matters of the traditional electric operating companies. Wholesale capacity revenues from PPAs are recognized in amounts billable under the contract terms. Energy and other revenues are generally recognized as services are provided. The contracts for capacity and energy in a wholesale PPA have multiple performance obligations where the contract's total transaction price is allocated to each performance obligation based on the standalone selling price. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, the traditional electric operating companies recognize revenue as the performance obligations are satisfied over time as electricity is delivered to the customer or as generation capacity is available to the customer. For both retail and wholesale revenues, the traditional electric operating companies have elected to recognize revenue for their sales of electricity and capacity using the invoice practical expedient as they generally have a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and that may be invoiced. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of the Registrants' performance obligation. Southern Power Southern Power sells capacity and energy at rates specified under contractual terms in long-term PPAs. These PPAs are accounted for as leases, non-derivatives, or normal sale derivatives. Capacity revenues from PPAs classified as operating leases are recognized on a straight-line basis over the term of the agreement. Energy revenues are recognized in the period the energy is delivered. Capacity revenues from PPAs classified as sales-type leases are recognized by accounting for interest income on the net investment in the lease. Southern Power's non-lease contracts commonly include capacity and energy which are considered separate performance obligations. In these contracts, the total transaction price is allocated to each performance obligation based on the standalone selling price. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, Southern Power recognizes revenue as the performance obligations are satisfied over time, as electricity is delivered to the customer or as generation capacity is made available to the customer. Southern Power generally has a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and may recognize revenue in the amount to which the entity has a right to invoice. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of Southern Power's performance obligation. When multiple contracts exist with the same counterparty, the revenues from each contract are accounted for as separate arrangements. Southern Power may also enter into contracts to sell short-term capacity in the wholesale electricity markets. These sales are generally classified as mark-to-market derivatives and net unrealized gains and losses on such contracts are recorded in wholesale revenues. See Note 14 and "Financial Instruments" herein for additional information. Southern Company Gas Gas Distribution Operations Southern Company Gas records revenues when goods or services are provided to customers. Those revenues are based on rates approved by the state regulatory agencies of the natural gas distribution utilities. Atlanta Gas Light operates in a deregulated natural gas market wher eby M arketers, rather than a traditional utility, sell natural gas to end-use customers in Georgia and handle customer billing functions. As required by the Georgia PSC, Atlanta Gas Light bills Marketers in equal monthly installments for each residential, commercial, and industrial end-use customer's distribution costs as well as for capacity costs utilizing a seasonal rate design for the calculation of each residential end-use customer's annual straight-fixed-variable charge, which reflects the historic volumetric usage pattern for the entire residential class. The majority of the revenues of Southern Company Gas are generated from contracts with natural gas distribution customers. Revenues from this integrated service to deliver gas when and if called upon by the customer are recognized as a single performance obligation satisfied over time and are recognized at a tariff rate as gas is delivered to the customer during the month. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, Southern Company Gas recognizes revenue as the performance obligations are satisfied over time as natural gas is delivered to the customer. The performance obligations related to wholesale gas services are satisfied, and revenue is recognized, at a point in time when natural gas is delivered to the customer. Southern Company Gas has elected to recognize revenue for sales of gas using the invoice practical expedient as it generally has a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and that may be invoiced. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of Southern Company Gas' performance obligation. With the exception of Atlanta Gas Light, the natural gas distribution utilities have rate structures that include volumetric rate designs that allow the opportunity to recover certain costs based on gas usage. Revenues from sales and transportation services are recognized in the same period in which the related volumes are delivered to customers. Revenues from residential and certain commercial and industrial customers are recognized on the basis of scheduled meter readings. Additionally, unbilled revenues are recognized for estimated deliveries of gas not yet billed to these customers, from the last bill date to the end of the accounting period. For other commercial and industrial customers, revenues are based on actual deliveries through the end of the period. The tariffs for the natural gas distribution utilities include provisions which allow for the recognition of certain revenues prior to the time such revenues are billed to customers. These provisions are referred to as alternative revenue programs and provide for the recognition of certain revenues prior to billing, as long as the amounts recognized will be collected from customers within 24 months of recognition. Revenue related to alternative revenue programs was $(5) million, $11 million, and $3 million in 2022, 2021, and 2020, respectively. These programs are as follows: • Weather normalization adjustments – reduce customer bills when winter weather is colder than normal and increase customer bills when weather is warmer than normal and are included in the tariffs for Virginia Natural Gas and Chattanooga Gas; • Revenue normalization mechanisms – mitigate the impact of conservation and declining customer usage and are contained in the tariffs for Virginia Natural Gas and Nicor Gas; and • Revenue true-up adjustment – included within the provisions of the GRAM program in which Atlanta Gas Light participates as a short-term alternative to formal rate case filings, the revenue true-up feature provides for a positive (or negative) adjustment to record revenue in the amount of any variance to budgeted revenues, which are submitted and approved annually as a requirement of GRAM. Such adjustments are reflected in customer billings in a subsequent program year. Wholesale Gas Services Prior to the sale of Sequent on July 1, 2021, Southern Company Gas netted revenues from energy and risk management activities with the associated costs. Profits from sales between segments were eliminated and recognized as goods or services sold to end-use customers. Southern Company Gas recorded wholesale gas services' transactions that qualified as derivatives at fair value with changes in fair value recognized in earnings in the period of change and characterized as unrealized gains or losses. Gains and losses on derivatives held for energy trading purposes were presented on a net basis in revenue. See Note 15 under "Southern Company Gas" for additional information on the sale of Sequent. Gas Marketing Services Southern Company Gas recognizes revenues from natural gas sales and transportation services in the same period in which the related volumes are delivered to customers and recognizes sales revenues from residential and certain commercial and industrial customers on the basis of scheduled meter readings. Southern Company Gas also recognizes unbilled revenues for estimated deliveries of gas not yet billed to these customers from the most recent meter reading date to the end of the accounting period. For other commercial and industrial customers and for all wholesale customers, revenues are based on actual deliveries during the period. Southern Company Gas recognizes revenues on 12-month utility-bill management contracts as the lesser of cumulative earned or cumulative billed amounts. Concentration of Revenue Southern Company, Alabama Power, Georgia Power, Mississippi Power (with the exception of its full requirements cost-based MRA electric tariffs described below), Southern Power, and Southern Company Gas each have a diversified base of customers and no single customer or industry comprises 10% or more of each company's revenues. Mississippi Power provides service under long-term contracts with rural electric cooperative associations and a municipality located in southeastern Mississippi under requirements cost-based MRA electric tariffs, which are subject to regulation by the FERC. The contracts with these wholesale customers represented 12.4% of Mississippi Power's total operating revenues in 2022. Historically, these wholesale customers have acted as a group and any changes in contractual relationships for one customer are likely to be followed by the other wholesale customers. Fuel Costs Fuel costs for the traditional electric operating companies and Southern Power are expensed as the fuel is used. Fuel expense generally includes fuel transportation costs and the cost of purchased emissions allowances as they are used. For Alabama Power and Georgia Power, fuel expense also includes the amortization of the cost of nuclear fuel. For the traditional electric operating companies, fuel costs also include gains and/or losses from fuel-hedging programs as approved by their respective state PSCs. Cost of Natural Gas Excluding Atlanta Gas Light, which does not sell natural gas to end-use customers, Southern Company Gas charges its utility customers for natural gas consumed using natural gas cost recovery mechanisms set by the applicable state regulatory agencies. Under these mechanisms, all prudently-incurred natural gas costs are passed through to customers without markup, subject to regulatory review. Southern Company Gas defers or accrues the difference between the actual cost of natural gas and the amount of commodity revenue earned in a given period such that no operating income is recognized related to these costs. The deferred or accrued amount is either billed or refunded to customers prospectively through adjustments to the commodity rate. Deferred and accrued natural gas costs are included in the balance sheets as regulatory assets and regulatory liabilities, respectively. Southern Company Gas' gas marketing services' customers are charged for actual or estimated natural gas consumed. Within cost of natural gas, Southern Company Gas also includes costs of lost and unaccounted for gas, adjustments to reduce the value of inventories to market value, and gains and losses associated with certain derivatives. Income Taxes The Registrants use the liability method of accounting for deferred income taxes and provide deferred income taxes for all significant income tax temporary differences. In accordance with regulatory requirements, deferred federal ITCs for the traditional electric operating companies are amortized over the average life of the related property, with such amortization normally applied as a credit to reduce depreciation and amortization in the statements of income. Southern Power's and the natural gas distribution utilities' deferred federal ITCs, as well as certain state ITCs for Nicor Gas, are amortized to income tax expense over the life of the respective asset. Under current tax law, certain projects at Southern Power related to the construction of renewable facilities are eligible for federal ITCs. Southern Power estimates eligible costs which, as they relate to acquisitions, may not be finalized until the allocation of the purchase price to assets has been finalized. Southern Power applies the deferred method to ITCs, whereby the ITCs are recorded as a deferred credit and amortized to income tax expense over the life of the respective asset. Furthermore, the tax basis of the asset is reduced by 50% of the ITCs received, resulting in a net deferred tax asset. Southern Power has elected to recognize the tax benefit of this basis difference as a reduction to income tax expense in the year in which the plant reaches commercial operation. State ITCs are recognized as an income tax benefit in the period in which the credits are generated. In addition, certain projects are eligible for federal and state PTCs, which are recognized as an income tax benefit based on KWH production. Federal ITCs and PTCs, as well as state ITCs and other state tax credits available to reduce income taxes payable, were not fully utilized in 2022 and will be carried forward and utilized in future years. In addition, Southern Company is expected to have various state net operating loss (NOL) carryforwards for certain of its subsidiaries, including Mississippi Power and Southern Power, which would result in income tax benefits in the future, if utilized. See Note 10 under "Current and Deferred Income Taxes – Tax Credit Carryforwards" and " – Net Operating Loss Carryforwards" for additional information. The Registrants recognize tax positions that are "more likely than not" of being sustained upon examination by the appropriate taxing authorities. See Note 10 under "Unrecognized Tax Benefits" for additional information. Other Taxes Taxes imposed on and collected from customers on behalf of governmental agencies are presented net on the Registrants' statements of income and are excluded from the transaction price in determining the revenue related to contracts with a customer. Southern Company Gas is taxed on its gas revenues by various governmental authorities, but is allowed to recover these taxes from its customers. Revenue taxes imposed on the natural gas distribution utilities are recorded at the amount charged to customers, which may include a small administrative fee, as operating revenues, and the related taxes imposed on Southern Company Gas are recorded as operating expenses on the statements of income. Revenue taxes included in operating expenses were $158 million, $119 million, and $104 million in 2022, 2021, and 2020, respectively. Allowance for Funds Used During Construction and Interest Capitalized The traditional electric operating companies and the natural gas distribution utilities record AFUDC, which represents the estimated debt and equity costs of capital funds that are necessary to finance the construction of new regulated facilities. While cash is not realized currently, AFUDC increases the revenue requirement and is recovered over the service life of the asset through a higher rate base and higher depreciation. The equity component of AFUDC is not taxable. Interest related to financing the construction of new facilities at Southern Power and new facilities not included in the traditional electric operating companies' and Southern Company Gas' regulated rates is capitalized in accordance with standard interest capita

REGULATORY MATTERS

REGULATORY MATTERS	12 Months Ended
	Dec. 31, 2022
Regulated Operations [Abstract]
REGULATORY MATTERS	REGULATORY MATTERS Regulatory Assets and Liabilities Details of regulatory assets and (liabilities) reflected in the balance sheets at December 31, 2022 and 2021 are provided in the following tables: Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) At December 31, 2022 AROs (a)(u) $ 6,096 $ 1,971 $ 3,829 $ 242 $ — Retiree benefit plans (b)(u) 2,517 675 848 113 114 Remaining net book value of retired assets (c) 1,543 562 962 19 — Under recovered regulatory clause revenues (d) 953 788 — 31 134 Deferred income tax charges (e) 866 250 583 30 — Environmental remediation (f)(u) 294 — 25 — 269 Loss on reacquired debt (g) 257 38 213 5 1 Vacation pay (h)(u) 212 82 108 10 12 Regulatory clauses (i) 142 142 — — — Software and cloud computing costs (j) 111 46 59 — 6 Nuclear outage (k) 82 52 30 — — Long-term debt fair value adjustment (l) 69 — — — 69 Fuel-hedging (realized and unrealized) losses (m) 60 15 45 — — Storm damage (n) 44 — — 44 — Plant Daniel Units 3 and 4 (o) 27 — — 27 — Kemper County energy facility assets, net (p) 20 — — 20 — Other regulatory assets (q) 197 36 27 16 118 Deferred income tax credits (e) (5,251) (1,925) (2,244) (269) (788) Other cost of removal obligations (a) (1,430) 11 462 (196) (1,707) Storm/property damage reserves (r) (216) (97) (83) (36) — Reliability reserves (r) (191) (166) — (25) — Customer refunds (s) (183) (62) (121) — — Fuel-hedging (realized and unrealized) gains (m ) (83) (38) (21) (24) — Over recovered regulatory clause revenues (d) (64) — (38) — (26) Other regulatory liabilities (t) (239) (40) (21) (3) (93) Total regulatory assets (liabilities), net $ 5,833 $ 2,340 $ 4,663 $ 4 $ (1,891) Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) At December 31, 2021 AROs (a)(u) $ 5,685 $ 1,576 $ 3,866 $ 236 $ — Retiree benefit plans (b)(u) 2,998 747 962 145 95 Remaining net book value of retired assets (c) 1,050 574 455 21 — Deferred income tax charges (e) 829 240 555 31 — Under recovered regulatory clause revenues (d) 806 225 — 49 532 Environmental remediation (f)(u) 302 — 35 — 267 Loss on reacquired debt (g) 281 42 231 6 2 Vacation pay (h)(u) 207 81 102 10 14 Regulatory clauses (i) 142 142 — — — Storm damage (n) 97 — 48 49 — Long-term debt fair value adjustment (l) 79 — — — 79 Nuclear outage (k) 75 41 34 — — Software and cloud computing costs (j) 73 35 33 — 5 Kemper County energy facility assets, net (p) 35 — — 35 — Plant Daniel Units 3 and 4 (o) 28 — — 28 — Other regulatory assets (q) 168 38 29 7 94 Deferred income tax credits (e) (5,636) (1,968) (2,537) (288) (816) Other cost of removal obligations (a) (1,826) (192) 278 (195) (1,683) Customer refunds (s ) (189) (181) (8) — — Fuel-hedging (realized and unrealized) gains (m) (176) (50) (72) (54) — Storm/property damage reserves (r) (133) (103) — (30) — Over recovered regulatory clause revenues (d) (63) (1) (59) — (3) Other regulatory liabilities (t) (121) (29) (24) (4) (57) Total regulatory assets (liabilities), net $ 4,711 $ 1,217 $ 3,928 $ 46 $ (1,471) Unless otherwise noted, the following recovery and amortization periods for these regulatory assets and (liabilities) have been approved by the respective state PSC or regulatory agency: (a) AROs and other cost of removal obligations generally are recorded over the related property lives, which may range up to 53 years for Alabama Power, 57 years for Georgia Power, 55 years for Mississippi Power, and 80 years for Southern Company Gas. AROs and cost of removal obligations are settled and trued up following completion of the related activities. Alabama Power is recovering CCR ARO expenditures over a 38-year period ending in 2054 through Rate CNP Compliance. Effective January 1, 2023, Georgia Power is recovering CCR ARO expenditures over four-year periods through its ECCR tariff. Prior to 2023, expenditures were recovered over three-year periods. See "Georgia Power – Rate Plans" herein and Note 6 for additional information. (b) Recovered and amortized over the average remaining service period, which may range up to 13 years for Alabama Power, Georgia Power, and Mississippi Power and up to 14 years for Southern Company Gas. Southern Company's balances also include amounts at SCS and Southern Nuclear that are allocated to the applicable regulated utilities. See Note 11 for additional information. (c) Alabama Power : Primarily represents the net book value of Plant Gorgas Units 8, 9, and 10 ($492 million at December 31, 2022) being amortized over remaining periods not exceeding 15 years (through 2037). Balance at December 31, 2022 also includes approximately $42 million related to Plant Barry Unit 4 being amortized over the unit's remaining useful life (through 2034). See "Alabama Power – Environmental Accounting Order" herein for additional information. Georgia Power : Net book values of Plant Wansley Units 1 and 2 (totaling $562 million at December 31, 2022) are being amortized over a remaining period of eight years (through 2030) and net book values of Plant Hammond Units 1 through 4 and Plant Branch Units 3 and 4 (totaling $396 million at December 31, 2022) are being amortized over remaining periods of between one Mississippi Power : Represents net book value of certain environmental compliance assets at Plant Watson and Plant Greene County. The retail portion is being amortized over a 10-year period through 2030 and the wholesale portion is being amortized over a 14-year period through 2035. See "Mississippi Power – Environmental Compliance Overview Plan" herein for additional information. (d) Alabama Power : Balances are recorded monthly and expected to be recovered over periods of up to eight years, with the majority expected to be recovered within two years. See "Alabama Power – Rate CNP PPA," " – Rate CNP Compliance," and " – Rate ECR" herein for additional information. Georgia Power : Balances are recorded monthly and expected to be recovered or returned within two years. See "Georgia Power – Rate Plans" herein for additional information. Mississippi Power : At December 31, 2022, $12 million is being amortized over a three-year period ending in 2023 and the remaining $18 million is expected to be recovered through various rate recovery mechanisms over a period to be determined in future rate filings. See "Mississippi Power – Ad Valorem Tax Adjustment" herein for additional information. Southern Company Gas : Balances are recorded and recovered or amortized over periods generally not exceeding five years. In addition to natural gas cost recovery mechanisms, the natural gas distribution utilities have various other cost recovery mechanisms for the recovery of costs, including those related to infrastructure replacement programs. (e) Deferred income tax charges are recovered and deferred income tax credits are amortized over the related property lives, which may range up to 53 years for Alabama Power, 57 years for Georgia Power, 55 years for Mississippi Power, and 80 years for Southern Company Gas. See Note 10 for additional information. As a result of the Tax Reform Legislation, these accounts include certain deferred income tax assets and liabilities not subject to normalization, as described further below: Alabama Power : Related amounts at December 31, 2022 include excess federal deferred income tax liabilities that are being returned to customers through bill credits of up to approximately $318 million in 2023, as discussed under "Alabama Power – Excess Accumulated Deferred Income Tax Accounting Order" herein. The Alabama PSC will determine the treatment of any remaining excess federal accumulated deferred income taxes at a future date. Remaining amounts are being recovered and amortized ratably over the related property lives. Georgia Power : Related amounts at December 31, 2022 include $145 million of deferred income tax assets related to CWIP for Plant Vogtle Units 3 and 4, the recovery of which is expected to be determined in a future regulatory proceeding. Mississippi Power : Related amounts at December 31, 2022 include $33 million of retail deferred income tax liabilities generally being amortized over three years through 2025. Southern Company Gas : Related amounts at December 31, 2022 include $1 million of deferred income tax liabilities being amortized through 2024. See "Southern Company Gas – Rate Proceedings" herein for additional information. (f) Effective January 1, 2023, Georgia Power is recovering $5 million annually for environmental remediation under the 2022 ARP. Southern Company Gas' costs are recovered through environmental cost recovery mechanisms when the remediation work is performed. See Note 3 under "Environmental Remediation" for additional information. (g) Recovered over either the remaining life of the original issue or, if refinanced, over the remaining life of the new issue. At December 31, 2022, the remaining amortization periods do not exceed 25 years for Alabama Power, 30 years for Georgia Power, 19 years for Mississippi Power, and five years for Southern Company Gas. (h) Recorded as earned by employees and recovered as paid, generally within one year. Includes both vacation and banked holiday pay, if applicable. (i) Effective January 1, 2023, balance is being amortized through Rate RSE over a five-year period ending in 2027. (j) Represents certain deferred operations and maintenance costs associated with software and cloud computing projects. For Alabama Power, costs are amortized ratably over the life of the related software, which ranges up to 10 years. See "Alabama Power – Software Accounting Order" herein for additional information. For Georgia Power, costs incurred through 2022 will be amortized over five years starting in 2023 and the recovery period for all future costs will be determined in its next base rate case. For Southern Company Gas, costs began being amortized ratably in July 2022 over the life of the related software, which ranges up to 10 years. (k) Nuclear outage costs are deferred to a regulatory asset when incurred and amortized over a subsequent period of 18 months for Alabama Power and up to 24 months for Georgia Power. See Note 5 for additional information. (l) Recovered over the remaining lives of the original debt issuances at acquisition, which range up to 16 years at December 31, 2022. (m) Fuel-hedging assets and liabilities are recorded over the life of the underlying hedged purchase contracts. Upon final settlement, actual costs incurred are recovered through the applicable traditional electric operating company's fuel cost recovery mechanism. Purchase contracts generally do not exceed three and a half years for Alabama Power, three years for Georgia Power, and four years for Mississippi Power. (n) Mississippi Power's balance represents deferred storm costs associated with Hurricanes Ida and Zeta being recovered through PEP over an eight-year period through 2029. (o) Represents the difference between Mississippi Power's revenue requirement for Plant Daniel Units 3 and 4 under purchase accounting and operating lease accounting. At December 31, 2022, consists of the $18 million retail portion being amortized through 2039 over the remaining life of the related property and the $9 million wholesale portion being amortized through 2035. (p) Includes $26 million of regulatory assets and $6 million of regulatory liabilities at December 31, 2022. The retail portion includes $17 million of regulatory assets and $6 million of regulatory liabilities that are expected to be fully amortized by 2023 and 2025, respectively. The wholesale portion includes $10 million of regulatory assets that are expected to be fully amortized by 2035. (q) Comprised of numerous immaterial components with remaining amortization periods generally not exceeding 21 years for Alabama Power, 10 years for Georgia Power, 14 years for Mississippi Power, and 20 years for Southern Company Gas at December 31, 2022. (r) Utilized as related expenses are incurred. See "Alabama Power – Rate NDR" and " – Reliability Reserve Accounting Order," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" and " – Reliability Reserve Accounting Order" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. (s) Primarily includes approximately $62 million and $181 million at December 31, 2022 and 2021, respectively, for Alabama Power and $119 million and $5 million at December 31, 2022 and 2021, respectively, for Georgia Power as a result of each company exceeding its allowed retail return range. Georgia Power's balances also include immaterial amounts related to refunds for transmission service customers. See "Alabama Power – Rate RSE" and "Georgia Power – Rate Plans" herein for additional information. (t) Comprised of numerous immaterial components with remaining amortization periods generally not exceeding 11 years for Alabama Power, 10 years for Georgia Power, four years for Mississippi Power, and 20 years for Southern Company Gas at December 31, 2022. (u) Generally not earning a return as they are excluded from rate base or are offset in rate base by a corresponding asset or liability. Alabama Power Alabama Power's revenues from regulated retail operations are collected through various rate mechanisms subject to the oversight of the Alabama PSC. Alabama Power currently recovers its costs from the regulated retail business primarily through Rate RSE, Rate CNP, Rate ECR, and Rate NDR. In addition, the Alabama PSC issues accounting orders to address current events impacting Alabama Power. Certificates of Convenience and Necessity In 2020, the Alabama PSC issued its order regarding Alabama Power's 2019 petition for a CCN, which authorized Alabama Power to (i) construct an approximately 720-MW combined cycle facility at Alabama Power's Plant Barry (Plant Barry Unit 8) that is expected to be placed in service in November 2023, (ii) complete the acquisition of the Central Alabama Generating Station, which occurred in August 2020, (iii) purchase approximately 240 MWs of combined cycle generation under a long-term PPA, which began in September 2020, and (iv) pursue up to approximately 200 MWs of cost-effective demand-side management and distributed energy resource programs. Alabama Power's petition for a CCN was predicated on the results of Alabama Power's 2019 IRP provided to the Alabama PSC, which identified an approximately 2,400-MW resource need for Alabama Power, driven by the need for additional winter reserve capacity. See Note 15 under "Alabama Power" for additional information on the acquisition of the Central Alabama Generating Station. The Alabama PSC authorized the recovery of actual costs for the construction of Plant Barry Unit 8 up to 5% above the estimated in-service cost of $652 million. In so doing, it recognized the potential for developments that could cause the project costs to exceed the capped amount, in which case Alabama Power would provide documentation to the Alabama PSC to explain and justify potential recovery of the additional costs. At December 31, 2022, project expenditures associated with Plant Barry Unit 8 totaled approximately $518 million, of which $513 million and $5 million was included in CWIP and property, plant, and equipment in service, respectively. The ultimate outcome of this matter cannot be determined at this time. Alabama Power expects to recover costs associated with Plant Barry Unit 8 pursuant to its Rate CNP New Plant. The recovery of costs associated with laws, regulations, and other such mandates directed at the utility industry are expected to be recovered through Rate CNP Compliance. Alabama Power expects to recover the capacity-related costs associated with the PPAs through its Rate CNP PPA. In addition, fuel and energy-related costs are expected to be recovered through Rate ECR. Any remaining costs associated with Plant Barry Unit 8 are expected to be recovered through Rate RSE. Through May 2023, Alabama Power expects to recover substantially all costs associated with the Central Alabama Generating Station through Rate RSE, offset by revenues from a previous power sales agreement. Beginning in July 2022, fuel costs associated with Central Alabama Generating Station are being recovered through Rate ECR. On July 12, 2022, the Alabama PSC approved a CCN authorizing Alabama Power to complete the acquisition of the Calhoun Generating Station, a 743-MW winter peak, simple-cycle, combustion turbine generation facility in Calhoun County, Alabama. The acquisition was approved by the FERC on March 25, 2022. The transaction closed on September 30, 2022 and, on October 3, 2022, Alabama Power filed Rate CNP New Plant with the Alabama PSC to recover the related costs, as described further under "Rate CNP New Plant" herein. Alabama Power is recovering the remaining costs associated with the Calhoun Generating Station through its existing rate structure, primarily Rate CNP Compliance, Rate ECR, and Rate RSE. Renewable Generation Certificate Alabama Power is authorized by the Alabama PSC to procure up to 500 MWs of renewable capacity and energy by September 16, 2027 and to market the related energy and environmental attributes to customers and other third parties. Through December 31, 2022, Alabama Power has procured solar capacity totaling approximately 330 MWs. Rate RSE The Alabama PSC has adopted Rate RSE that provides for periodic annual adjustments based upon Alabama Power's projected weighted common equity return (WCER) compared to an allowable range. Rate RSE adjustments are based on forward-looking information for the applicable upcoming calendar year. Rate RSE adjustments for any two-year period, when averaged together, cannot exceed 4.0% and any annual adjustment is limited to 5.0%. When the projected WCER is under the allowed range, there is an adjusting point of 5.98% and eligibility for a performance-based adder of seven basis points, or 0.07%, to the WCER adjusting point if Alabama Power (i) has an "A" credit rating equivalent with at least one of the recognized rating agencies or (ii) is in the top one-third of a designated customer value benchmark survey. Alabama Power continues to reduce growth in total debt by increasing equity, with corresponding reductions in debt issuances, thereby de-leveraging its capital structure. Alabama Power's goal is to achieve an equity ratio of approximately 55% by the end of 2025. At December 31, 2022 and 2021, Alabama Power's equity ratio was approximately 52.2% and 51.6%, respectively. Generally, during a year without a Rate RSE upward adjustment, if Alabama Power's actual WCER is between 6.15% and 7.65%, customers will receive 25% of the amount between 6.15% and 6.65%, 40% of the amount between 6.65% and 7.15%, and 75% of the amount between 7.15% and 7.65%. Customers will receive all amounts in excess of an actual WCER of 7.65%. During a year with a Rate RSE upward adjustment, if Alabama Power's actual WCER exceeds 6.15%, customers receive 50% of the amount between 6.15% and 6.90% and all amounts in excess of an actual WCER of 6.90%. Alabama Power's ability to retain a portion of the revenue that causes the actual WCER for a given year to exceed the allowed range positions Alabama Power to address the growing pressure on its credit quality, without increasing retail rates under Rate RSE in the near term. There is no provision for additional customer billings should the actual retail return fall below the WCER range. Retail rates under Rate RSE did not change for 2020 or 2022 and increased by 4.09%, or approximately $228 million annually, effective with the billing month of January 2021. At December 31, 2020, 2021, and 2022 Alabama Power's WCER exceeded 6.15%, resulting in Alabama Power establishing a current regulatory liability of $50 million, $181 million, and $62 million, respectively, for Rate RSE refunds. The 2020 refund was issued to customers through bill credits in April 2021. In accordance with an Alabama PSC order issued on February 1, 2022, Alabama Power applied $126 million of the 2021 refund to reduce the Rate ECR under recovered balance and the remaining $55 million was refunded to customers through bill credits in July 2022. See "Rate ECR" herein for additional information. On February 7, 2023, the Alabama PSC directed Alabama Power to issue the 2022 refund to customers through bill credits in August 2023. On December 1, 2022, Alabama Power made its required annual Rate RSE submission to the Alabama PSC of projected data for calendar year 2023. Projected earnings were within the specified range; therefore, retail rates under Rate RSE remain unchanged for 2023. Excess Accumulated Deferred Income Tax Accounting Order On December 6, 2022, the Alabama PSC directed Alabama Power to accelerate the amortization of a regulatory liability associated with excess federal accumulated deferred income taxes, which is being returned to customers through bill credits of up to approximately $318 million in 2023 to offset the impact of the rate increase discussed under "Rate CNP Depreciation" herein. The Alabama PSC will determine the treatment of any remaining excess federal accumulated deferred income taxes at a future date. The ultimate outcome of this matter cannot be determined at this time. Rate CNP New Plant Rate CNP New Plant allows for recovery of Alabama Power's retail costs associated with newly developed or acquired certificated generating facilities placed into retail service. No adjustments to Rate CNP New Plant occurred during the period January 2020 through October 2022. On October 3, 2022, Alabama Power filed Rate CNP New Plant with the Alabama PSC to recover costs related to the acquisition of the Calhoun Generating Station. The filing reflected an increase in annual revenues of $34 million, or 0.6%, effective with November 2022 billings. See "Certificates of Convenience and Necessity" herein for additional information. Rate CNP PPA Rate CNP PPA allows for the recovery of Alabama Power's retail costs associated with certificated PPAs. Revenues for Rate CNP PPA, as recorded on the financial statements, are adjusted for differences in actual recoverable costs and amounts billed in current regulated rates. Accordingly, changes in the billing factor will have no significant effect on Southern Company's or Alabama Power's revenues or net income but will affect annual cash flow. No adjustments to Rate CNP PPA occurred during the period 2020 through 2022 and no adjustment is expected for 2023. At December 31, 2022, Alabama Power had an under recovered Rate CNP PPA balance of $120 million, of which $18 million is included in other regulatory assets, current and $102 million is included in other regulatory assets, deferred on the balance sheet. At December 31, 2021, Alabama Power had an under recovered Rate CNP PPA balance of $84 million included in other regulatory assets, deferred on the balance sheet. Rate CNP Compliance Rate CNP Compliance allows for the recovery of Alabama Power's retail costs associated with laws, regulations, and other such mandates directed at the utility industry involving the environment, security, reliability, safety, sustainability, or similar considerations impacting Alabama Power's facilities or operations. Rate CNP Compliance is based on forward-looking information and provides for the recovery of these costs pursuant to factors that are calculated and submitted to the Alabama PSC by December 1 with rates effective for the following calendar year. Compliance costs to be recovered include operations and maintenance expenses, depreciation, and a return on certain invested capital. Revenues for Rate CNP Compliance, as recorded on the financial statements, are adjusted for differences in actual recoverable costs and amounts billed in current regulated rates. Accordingly, changes in the billing factor will have no significant effect on Southern Company's or Alabama Power's revenues or net income, but will affect annual cash flow. Changes in Rate CNP Compliance-related operations and maintenance expenses and depreciation generally will have no effect on net income. In November 2020, November 2021, and December 2022, Alabama Power submitted calculations associated with its cost of complying with governmental mandates for the following calendar year, as provided under Rate CNP Compliance. Both the 2020 and 2021 filings reflected a projected under recovered retail revenue requirement of approximately $59 million. In December 2020 and 2021, the Alabama PSC issued consent orders that Alabama Power leave the 2020 Rate CNP Compliance factors in effect for 2021 and 2022, respectively, with any prior year under collected amount deemed recovered before any current year amounts are recovered, and any remaining under recovery reflected in the 2022 filing. The 2022 filing reflected a $255 million, or 3.7%, annual increase effective with January 2023 billings, primarily due to updated depreciation rates. At December 31, 2022 and 2021, Alabama Power had an under recovered Rate CNP Compliance balance of $47 million and $16 million, respectively, included in other regulatory assets, current and other regulatory assets, deferred, respectively, on the balance sheet. Rate CNP Depreciation On December 6, 2022, the Alabama PSC approved Rate CNP Depreciation, which allows Alabama Power to recover changes in depreciation resulting from updates to certain depreciation rates, excluding any depreciation recovered through Rate CNP New Plant, Rate CNP Compliance, or costs associated with the capitalization of asset retirement costs. Rate CNP Depreciation will result in an annual revenue increase of approximately $318 million, or 4.6%, effective with January 2023 billings. See "Excess Accumulated Deferred Income Tax Accounting Order" herein for information related to 2023 customer bill credits approved by the Alabama PSC. Rate ECR Rate ECR recovers Alabama Power's retail energy costs based on an estimate of future energy costs and the current over or under recovered balance. Revenues recognized under Rate ECR and recorded on the financial statements are adjusted for the difference in actual recoverable fuel costs and amounts billed in current regulated rates. The difference in the recoverable fuel costs and amounts billed gives rise to the over or under recovered amounts recorded as regulatory assets or liabilities. Alabama Power, along with the Alabama PSC, continually monitors the over or under recovered cost balance to determine whether an adjustment to billing rates is required. Changes in the Rate ECR factor have no significant effect on Southern Company's or Alabama Power's net income but will impact the related operating cash flows. The Alabama PSC may approve billing rates under Rate ECR of up to 5.910 cents per KWH. In 2020, Alabama Power reduced its over-collected fuel balance by $94 million in accordance with an Alabama PSC order and returned that amount to customers in the form of bill credits. Also in 2020, the Alabama PSC approved a decrease to Rate ECR from 2.160 cents per KWH to 1.960 cents per KWH, equal to 1.84%, or approximately $103 million annually, that became effective with January 2021 billings and remained in effect through July 2022 billings. The Alabama PSC approved adjustments to Rate ECR from 1.960 cents per KWH to 2.557 cents per KWH, or approximately $310 million annually, effective with August 2022 billings and from 2.557 cents per KWH to 3.510 cents per KWH, or approximately $500 million annually, effective with December 2022 billings. The rate will adjust to 5.910 cents per KWH in January 2025 absent a further order from the Alabama PSC. In accordance with an Alabama PSC order issued on February 1, 2022, Alabama Power applied $126 million of its 2021 Rate RSE refund to reduce the Rate ECR under recovered balance. See "Rate RSE" herein for additional information. At December 31, 2022, Alabama Power's under recovered fuel costs totaled $622 million, of which $102 million is included in other regulatory assets, current and $520 million is included in other regulatory assets, deferred on the balance sheet. At December 31, 2021, Alabama Power's under recovered fuel costs totaled $126 million and is included in other regulatory assets, deferred on the balance sheet. These classifications are based on estimates, which include such factors as weather, generation availability, energy demand, and the price of energy. A change in any of these factors could have a significant impact on the timing of any recovery or return of fuel costs. Software Accounting Order The Alabama PSC authorizes Alabama Power to establish a regulatory asset for operations and maintenance costs associated with software implementation projects. The regulatory asset is amortized ratably over the life of the related software. At December 31, 2022 and 2021, the regulatory asset balance totaled $46 million and $35 million, respectively, and is included in other regulatory assets, deferred on the balance sheet. Plant Greene County Alabama Power jointly owns Plant Greene County with an affiliate, Mississippi Power. See Note 5 under "Joint Ownership Agreements" for additional information. In September 2021, the Mississippi PSC issued an order confirming the conclusion of its review of Mississippi Power's 2021 IRP with no deficiencies identified. Mississippi Power's 2021 IRP included a schedule to retire Mississippi Power's 40% ownership interest in Plant Greene County Units 1 and 2 in December 2025 and 2026, respectively, consistent with each unit's remaining useful life. The Plant Greene County unit retirements identified by Mississippi Power require the completion of transmission and system reliability improvements, as well as agreement by Alabama Power. Alabama Power will continue to monitor the status of the transmission and system reliability improvements. Currently, Alabama Power plans to retire Plant Greene County Units 1 and 2 at the dates indicated. The ultimate outcome of this matter cannot be determined at this time. Rate NDR Based on an order from the Alabama PSC, Alabama Power maintains a reserve for operations and maintenance expenses to cover the cost of damages from major storms to its transmission and distribution facilities. The order approves a separate monthly Rate NDR charge to customers consisting of two components. The first component is intended to establish and maintain a reserve balance for future storms and is an on-going part of customer billing. When the reserve balance falls below $50 million, a reserve establishment charge will be activated (and the on-going reserve maintenance charge concurrently suspended) until the reserve balance reaches $75 million. The second component of the Rate NDR charge is intended to allow recovery of any existing deferred storm-related operations and maintenance costs and any future reserve deficits over a 48-month period (24-month period prior to modifications approved by the Alabama PSC on July 12, 2022). The Alabama PSC order gives Alabama Power authority to record a deficit balance in the NDR when costs of storm damage exceed any established reserve balance. The maximum total Rate NDR charge was limited to $10.00 per month per non-residential customer account and $5.00 per month per residential customer account through July 12, 2022. Subsequently, modifications approved by the Alabama PSC replaced the maximum total Rate NDR charge with a maximum charge to recover a deficit of $5 per month per non-residential customer account and $2.50 per month per residential customer account. Alabama Power has the authority, based on an order from the Alabama PSC, to accrue certain additional amounts as circumstances warrant, which can be used to offset storm charges. Alabama Power made additional accruals of $65 million and $100 million in 2021 and 2020, respectively. Alabama Power collected approximately $14 million, $6 million, and $5 million in 2022, 2021, and 2020, respectively, under Rate NDR. Beginning with August 2022 billings, the reserve establishment charge was suspended and the reserve maintenance charge was activated as a result of the NDR balance exceeding $75 million. Alabama Power expects to collect approximately $12 million annually under Rate NDR unless the NDR balance falls below $50 million. At December 31, 2022 and 2021, the NDR balance was $97 million and $103 million, respectively, and is included in other regulatory liabilities, deferred on the balance sheets. As revenue from the Rate NDR charge is recognized, an equal amount of operations and maintenance expenses related to the NDR

CONTINGENCIES, COMMITMENTS, AND

CONTINGENCIES, COMMITMENTS, AND GUARANTEES	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
CONTINGENCIES, COMMITMENTS, AND GUARANTEES	CONTINGENCIES, COMMITMENTS, AND GUARANTEES General Litigation Matters The Registrants are involved in various matters being litigated and regulatory matters. The ultimate outcome of such pending or potential litigation or regulatory matters against each Registrant and any subsidiaries cannot be determined at this time; however, for current proceedings not specifically reported herein, management does not anticipate that the ultimate liabilities, if any, arising from such current proceedings would have a material effect on such Registrant's financial statements. The Registrants believe the pending legal challenges discussed below have no merit; however, the ultimate outcome of these matters cannot be determined at this time. Alabama Power On September 26, 2022, Mobile Baykeeper, through its counsel Southern Environmental Law Center, filed a citizen suit in the U.S. District Court for the Southern District of Alabama alleging that Alabama Power's plan to close the Plant Barry ash pond utilizing a closure-in-place methodology violates the Resource Conservation and Recovery Act (RCRA) and regulations governing CCR. Among other relief requested, Mobile Baykeeper seeks a declaratory judgment that the RCRA and regulations governing CCR are being violated, preliminary and injunctive relief to prevent implementation of Alabama Power's closure plan and the development of a closure plan that satisfies regulations governing CCR requirements. On January 31, 2023, the EPA issued a Notice of Potential Violations associated with Alabama Power's plan to close the Plant Barry ash pond. Alabama Power expects to respond by March 2, 2023, subject to any extension agreed upon by the parties. The ultimate outcome of these matters cannot be determined at this time but could have an impact on Alabama Power's ARO estimates. See Note 6 for a discussion of Alabama Power's ARO liabilities. Georgia Power Municipal Franchise Fees In 2011, plaintiffs filed a putative class action against Georgia Power in the Superior Court of Fulton County, Georgia alleging that Georgia Power's collection in rates of amounts for municipal franchise fees (which fees are paid to municipalities) exceeded the amounts allowed in orders of the Georgia PSC and alleging certain state law claims. This case has been ruled upon and appealed numerous times over the last several years. In 2019, the Georgia PSC issued an order that found Georgia Power has appropriately implemented the municipal franchise fee schedule. In March 2021, the Superior Court of Fulton County granted class certification and Georgia Power's motion for summary judgment and the plaintiffs filed a notice of appeal. In April 2021, Georgia Power filed a notice of cross appeal on the issue of class certification. In December 2021, the Georgia Court of Appeals affirmed the Superior Court's ruling that granted summary judgment to Georgia Power and dismissed Georgia Power's cross appeal on the issue of class certification as moot. Also in December 2021, the plaintiffs filed a petition for writ of certiorari to the Georgia Supreme Court, which was denied on January 27, 2023. On February 6, 2023, the plaintiffs filed a motion for reconsideration with the Georgia Supreme Court. The amount of any possible losses cannot be estimated at this time because, among other factors, it is unknown whether any losses would be subject to recovery from any municipalities. Plant Scherer In July 2020, a group of individual plaintiffs filed a complaint, which was amended on December 9, 2022, in the Superior Court of Fulton County, Georgia against Georgia Power alleging that the construction and operation of Plant Scherer has impacted groundwater and air, resulting in alleged personal injuries and property damage. The plaintiffs seek an unspecified amount of monetary damages including punitive damages, a medical monitoring fund, and injunctive relief. Georgia Power has filed multiple motions to dismiss the complaint. On December 29, 2022, the Superior Court of Fulton County, Georgia granted Georgia Power's motion to transfer the case to the Superior Court of Monroe County, Georgia. In October 2021 and on February 7, 2022, a total of seven additional complaints were filed in the Superior Court of Monroe County, Georgia against Georgia Power alleging that releases from Plant Scherer have impacted groundwater and air, resulting in alleged personal injuries and property damage. The plaintiffs seek an unspecified amount of monetary damages including punitive damages. In November 2021 and March 2022, Georgia Power removed these cases to the U.S. District Court for the Middle District of Georgia. On November 16, 2022, the plaintiffs voluntarily dismissed their complaints without prejudice. Georgia Power anticipates that these plaintiffs will refile their complaints. On January 9, 2023, an additional complaint was filed in the Superior Court of Monroe County, Georgia against Georgia Power alleging that the construction and operation of Plant Scherer have impacted groundwater and air, resulting in alleged personal injuries. The plaintiff seeks an unspecified amount of monetary damages, including punitive damages. On January 19, 2023, Georgia Power filed a notice to remove the case to the U.S. District Court for the Middle District of Georgia. Mississippi Power In 2018, Ray C. Turnage and 10 other individual plaintiffs filed a putative class action complaint against Mississippi Power and the three then-serving members of the Mississippi PSC in the U.S. District Court for the Southern District of Mississippi, which was amended in March 2019 to include four additional plaintiffs. Mississippi Power received Mississippi PSC approval in 2013 to charge a mirror CWIP rate premised upon including in its rate base pre-construction and construction costs for the Kemper IGCC prior to placing the Kemper IGCC into service. The Mississippi Supreme Court reversed that approval and ordered Mississippi Power to refund the amounts paid by customers under the previously-approved mirror CWIP rate. The plaintiffs allege that the initial approval process, and the amount approved, were improper and make claims for gross negligence, reckless conduct, and intentional wrongdoing. They also allege that Mississippi Power underpaid customers by up to $23.5 million in the refund process by applying an incorrect interest rate. The plaintiffs seek to recover, on behalf of themselves and their putative class, actual damages, punitive damages, pre-judgment interest, post-judgment interest, attorney's fees, and costs. The district court dismissed the amended complaint; however, in March 2020, the plaintiffs filed a motion seeking to name the new members of the Mississippi PSC, the Mississippi Development Authority, and Southern Company as additional defendants and add a cause of action against all defendants based on a dormant commerce clause theory under the U.S. Constitution. In July 2020, the plaintiffs filed a motion for leave to file a third amended complaint, which included the same federal claims as the proposed second amended complaint, as well as several additional state law claims based on the allegation that Mississippi Power failed to disclose the annual percentage rate of interest applicable to refunds. In November 2020, the district court denied each of the plaintiffs' pending motions and entered final judgment in favor of Mississippi Power. In January 2021, the district court denied further motions by the plaintiffs to vacate the judgment and to file a revised second amended complaint. In February 2021, the plaintiffs filed a notice of appeal with the U.S. Court of Appeals for the Fifth Circuit. On March 21, 2022, the U.S. Court of Appeals for the Fifth Circuit issued an opinion affirming the dismissal of the claims against the Mississippi PSC defendants but reversing the dismissal of the claims against Mississippi Power. On May 31, 2022, the U.S. Court of Appeals for the Fifth Circuit denied a petition by Mississippi Power for a rehearing en banc and remanded the case to the U.S. District Court for the Southern District of Mississippi for further proceedings. On June 17, 2022, Mississippi Power filed with the trial court a motion to dismiss the complaint. An adverse outcome in this proceeding could have a material impact on Mississippi Power's financial statements. Environmental Remediation The Southern Company system must comply with environmental laws and regulations governing the handling and disposal of waste and releases of hazardous substances. Under these various laws and regulations, the Southern Company system could incur substantial costs to clean up affected sites. The traditional electric operating companies and the natural gas distribution utilities conduct studies to determine the extent of any required cleanup and have recognized the estimated costs to clean up known impacted sites in the financial statements. A liability for environmental remediation costs is recognized only when a loss is determined to be probable and reasonably estimable and is reduced as expenditures are incurred. The traditional electric operating companies and the natural gas distribution utilities in Illinois and Georgia have each received authority from their respective state PSCs or other applicable state regulatory agencies to recover approved environmental remediation costs through regulatory mechanisms. Any difference between the liabilities accrued and costs recovered through rates is deferred as a regulatory asset or liability. These regulatory mechanisms are adjusted annually or as necessary within limits approved by the state PSCs or other applicable state regulatory agencies. Georgia Power has been designated or identified as a potentially responsible party at sites governed by the Georgia Hazardous Site Response Act and/or by the federal Comprehensive Environmental Response, Compensation, and Liability Act, and assessment and potential cleanup of such sites is expected. For all years presented, Georgia Power recovered approximately $12 million annually through the ECCR tariff for environmental remediation under the 2019 ARP. Effective January 1, 2023, Georgia Power is recovering $5 million annually through the ECCR tariff under the 2022 ARP. Southern Company Gas is subject to environmental remediation liabilities associated with 40 former MGP sites in four different states. Southern Company Gas' accrued environmental remediation liability at December 31, 2022 and 2021 was based on the estimated cost of environmental investigation and remediation associated with these sites. At December 31, 2022 and 2021, the environmental remediation liability and the balance of under recovered environmental remediation costs were reflected in the balance sheets of Southern Company, Georgia Power, and Southern Company Gas as shown in the table below. Alabama Power did not have environmental remediation liabilities at December 31, 2022 or 2021. Mississippi Power did not have environmental remediation liabilities at December 31, 2022 and had an immaterial balance at December 31, 2021. Southern Company Georgia Southern Company Gas (in millions) December 31, 2022: Environmental remediation liability: Other current liabilities $ 65 $ 15 $ 49 Accrued environmental remediation 207 — 207 Under recovered environmental remediation costs: Other regulatory assets, current $ 59 $ 5 $ 54 Other regulatory assets, deferred 235 20 215 December 31, 2021: Environmental remediation liability: Other current liabilities $ 69 $ 17 $ 52 Accrued environmental remediation 197 — 197 Under recovered environmental remediation costs: Other regulatory assets, current $ 71 $ 12 $ 59 Other regulatory assets, deferred 231 23 208 The ultimate outcome of these matters cannot be determined at this time; however, as a result of the regulatory treatment for environmental remediation expenses described above, the final disposition of these matters is not expected to have a material impact on the financial statements of the applicable Registrants. Nuclear Fuel Disposal Costs Acting through the DOE and pursuant to the Nuclear Waste Policy Act of 1982, the U.S. government entered into contracts with Alabama Power and Georgia Power that required the DOE to dispose of spent nuclear fuel generated at Plants Farley, Hatch, and Vogtle Units 1 and 2 beginning no later than January 31, 1998. The DOE has yet to commence the performance of its contractual and statutory obligation to dispose of spent nuclear fuel. Consequently, Alabama Power and Georgia Power pursued and continue to pursue legal remedies against the U.S. government for its partial breach of contract. In 2014, Alabama Power and Georgia Power filed lawsuits against the U.S. government for the costs of continuing to store spent nuclear fuel at Plants Farley, Hatch, and Vogtle Units 1 and 2 for the period from January 1, 2011 through December 31, 2013. The damage period was subsequently extended to December 31, 2014. In 2019, the Court of Federal Claims granted Alabama Power's and Georgia Power's motion for summary judgment on damages not disputed by the U.S. government, awarding those undisputed damages to Alabama Power and Georgia Power. However, those undisputed damages are not collectible until the court enters final judgment on the remaining damages. In 2017, Alabama Power and Georgia Power filed additional lawsuits against the U.S. government in the Court of Federal Claims for the costs of continuing to store spent nuclear fuel at Plants Farley, Hatch, and Vogtle Units 1 and 2 for the period from January 1, 2015 through December 31, 2017. In 2020, Alabama Power and Georgia Power filed amended complaints in each of the lawsuits adding damages from January 1, 2018 to December 31, 2019 to the claim period. The outstanding claims for the period January 1, 2011 through December 31, 2019 total $110 million and $132 million for Alabama Power and Georgia Power (based on its ownership interests), respectively. Damages will continue to accumulate until the issue is resolved, the U.S. government disposes of Alabama Power's and Georgia Power's spent nuclear fuel pursuant to its contractual obligations, or alternative storage is otherwise provided. No amounts have been recognized in the financial statements as of December 31, 2022 for any potential recoveries from the pending lawsuits. The final outcome of these matters cannot be determined at this time. However, Alabama Power and Georgia Power expect to credit any recoveries for the benefit of customers in accordance with direction from their respective PSC; therefore, no material impact on Southern Company's, Alabama Power's, or Georgia Power's net income is expected. On-site dry spent fuel storage facilities are operational at all three plants and can be expanded to accommodate spent fuel through the expected life of each plant. Nuclear Insurance Under the Price-Anderson Amendments Act (Act), Alabama Power and Georgia Power maintain agreements of indemnity with the NRC that, together with private insurance, cover third-party liability arising from any nuclear incident occurring at the companies' nuclear power plants. The Act provides funds up to $13.7 billion for public liability claims that could arise from a single nuclear incident. Each nuclear plant is insured against this liability to a maximum of $450 million by American Nuclear Insurers (ANI), with the remaining coverage provided by a mandatory program of deferred premiums that could be assessed, after a nuclear incident, against all owners of commercial nuclear reactors. A company could be assessed up to $138 million per incident for each licensed reactor it operates but not more than an aggregate of $20 million per incident to be paid in a calendar year for each reactor. Such maximum assessment, excluding any applicable state premium taxes, for Alabama Power and Georgia Power, based on its ownership and buyback interests in all licensed reactors, is $275 million and $330 million, respectively, per incident, but not more than an aggregate of $41 million and $49 million, respectively, to be paid for each incident in any one year. Both the maximum assessment per reactor and the maximum yearly assessment are adjusted for inflation at least every five years. The next scheduled adjustment is due no later than November 1, 2023. See Note 5 under "Joint Ownership Agreements" for additional information on joint ownership agreements. Alabama Power and Georgia Power are members of Nuclear Electric Insurance Limited (NEIL), a mutual insurer established to provide property damage insurance in an amount up to $1.5 billion for members' operating nuclear generating facilities. Additionally, both companies have NEIL policies that currently provide decontamination, excess property insurance, and premature decommissioning coverage up to $1.25 billion for nuclear losses and policies providing coverage up to $750 million for non-nuclear losses in excess of the $1.5 billion primary coverage. NEIL also covers the additional costs that would be incurred in obtaining replacement power during a prolonged accidental outage at a member's nuclear plant. Members can purchase this coverage, subject to a deductible waiting period of up to 26 weeks, with a maximum per occurrence per unit limit of $490 million. After the deductible period, weekly indemnity payments would be received until either the unit is operational or until the limit is exhausted. Alabama Power and Georgia Power each purchase limits based on the projected full cost of replacement power, subject to ownership limitations, and have each elected a 12-week deductible waiting period for each nuclear plant. A builders' risk property insurance policy has been purchased from NEIL for the construction of Plant Vogtle Units 3 and 4. This policy provides the Vogtle Owners up to $2.75 billion for accidental property damage occurring during construction. Under each of the NEIL policies, members are subject to assessments each year if losses exceed the accumulated funds available to the insurer. The maximum annual assessments for Alabama Power and Georgia Power as of December 31, 2022 under the NEIL policies would be $51 million and $85 million, respectively. Claims resulting from terrorist acts and cyber events are covered under both the ANI and NEIL policies (subject to normal policy limits). The maximum aggregate that NEIL will pay for all claims resulting from terrorist acts and cyber events in any 12-month period is $3.2 billion each, plus such additional amounts NEIL can recover through reinsurance, indemnity, or other sources. For all on-site property damage insurance policies for commercial nuclear power plants, the NRC requires that the proceeds of such policies shall be dedicated first for the sole purpose of placing the reactor in a safe and stable condition after an accident. Any remaining proceeds are to be applied next toward the costs of decontamination and debris removal operations ordered by the NRC, and any further remaining proceeds are to be paid either to the applicable company or to its debt trustees as may be appropriate under the policies and applicable trust indentures. In the event of a loss, the amount of insurance available might not be adequate to cover property damage and other expenses incurred. Uninsured losses and other expenses, to the extent not recovered from customers, would be borne by Alabama Power or Georgia Power, as applicable, and could have a material effect on Southern Company's, Alabama Power's, and Georgia Power's financial condition and results of operations. Other Matters Traditional Electric Operating Companies In April 2019, Bellsouth Telecommunications d/b/a AT&T Alabama (AT&T) filed a complaint against Alabama Power with the FCC alleging that the pole rental rate AT&T is required to pay pursuant to the parties' joint use agreement is unjust and unreasonable under federal law. The complaint sought a new rate and approximately $87 million in refunds of alleged overpayments for the preceding six years. In August 2019, the FCC stayed the case in favor of arbitration, which AT&T has not pursued. The ultimate outcome of this matter cannot be determined at this time, but an adverse outcome could have a material impact on the financial statements of Southern Company and Alabama Power. Georgia Power and Mississippi Power have joint use agreements with other AT&T affiliates. Mississippi Power Kemper County Energy Facility In 2020, 2021, and 2022, Mississippi Power recorded charges to income associated with abandonment and related closure costs and ongoing period costs, net of salvage proceeds, for the mine and gasifier-related assets at the Kemper County energy facility. These charges, including related tax impacts, totaled $4 million pre-tax ($3 million after tax) in 2020, $11 million pre-tax ($8 million after tax) in 2021, and $15 million pre-tax ($12 million after tax) in 2022. The pre-tax charges are included in other operations and maintenance expenses on the statements of income. Dismantlement of the abandoned gasifier-related assets and site restoration activities are expected to be completed by 2026. Additional pre-tax period costs associated with dismantlement and site restoration activities, including related costs for compliance and safety, ARO accretion, and property taxes, net of salvage, are estimated to total approximately $15 million annually through 2025. Mississippi Power owns the lignite mine located around the Kemper County energy facility site. As a result of the abandonment of the Kemper IGCC, final mine reclamation began in 2018 and was substantially completed in 2020, with monitoring expected to continue through 2028. As the mining permit holder, Liberty Fuels Company, LLC, a wholly-owned subsidiary of The North American Coal Corporation, has a legal obligation to perform mine reclamation and Mississippi Power has a contractual obligation to fund all reclamation activities. See Note 6 for additional information. In 2010, the DOE, through a cooperative agreement with SCS, agreed to fund $270 million of the Kemper County energy facility through the grants awarded to the project by the DOE under the Clean Coal Power Initiative Round 2. In 2016, additional DOE grants in the amount of $137 million were awarded to the Kemper County energy facility. In 2018, Mississippi Power filed with the DOE its request for property closeout certification under the contract related to the $387 million of total grants received. In 2020, Mississippi Power and Southern Company executed an agreement with the DOE completing Mississippi Power's request, which enabled Mississippi Power to proceed with full dismantlement of the abandoned gasifier-related assets and site restoration activities. In connection with the DOE closeout discussions, in 2019, the Civil Division of the Department of Justice informed Southern Company and Mississippi Power of an investigation related to the grants received. The ultimate outcome of this matter cannot be determined at this time; however, it could have a material impact on Southern Company's and Mississippi Power's financial statements. Plant Daniel In conjunction with Southern Company's 2019 sale of Gulf Power, NextEra Energy held back $75 million of the purchase price pending Mississippi Power and NextEra Energy negotiating a mutually acceptable revised operating agreement for Plant Daniel. On July 12, 2022, the co-owners executed a revised operating agreement and Southern Company subsequently received the remaining $75 million of the purchase price. The dispatch procedures in the revised operating agreement for the two jointly-owned coal units at Plant Daniel resulted in Mississippi Power designating one of the two units as primary and the other as secondary in lieu of each company separately owning 100% of a single generating unit. Mississippi Power has the option to purchase its co-owner's ownership interest for $1 on January 15, 2024, provided that Mississippi Power exercises the option no later than 120 days prior to that date. The revised operating agreement did not have a material impact on Mississippi Power's financial statements. See Note 2 under "Mississippi Power – Integrated Resource Plan" for additional information on Plant Daniel. Department of Revenue Audit On August 31, 2022, the Mississippi Department of Revenue (Mississippi DOR) completed an audit of sales and use taxes paid by Mississippi Power from 2016 to 2019 and entered a final assessment, indicating a total amount due of $28 million, including associated penalties and interest. Mississippi Power does not agree with the audit findings and, o n October 27, 2022, filed an administrative appeal with the Mississippi DOR. On December 6, 2022, the Mississippi PSC approved an accounting order authorizing Mississippi Power to defer the additional taxes and related interest related to the audit to a regulatory asset, excluding amounts associated with the gasifier and other abandoned Kemper IGCC assets. The authority to defer these costs is not a guarantee of recovery. The review and final disposition of the costs recorded to the regulatory asset will be addressed in a future rate proceeding following completion of the tax audit proceedings. The ultimate outcome of this matter cannot be determined at this time. Commitments To supply a portion of the fuel requirements of the Southern Company system's electric generating plants, the Southern Company system has entered into various long-term commitments not recognized on the balance sheets for the procurement and delivery of fossil fuel and, for Alabama Power and Georgia Power, nuclear fuel. The majority of the Registrants' fuel expense for the periods presented was purchased under long-term commitments. Each Registrant expects that a substantial amount of its future fuel needs will continue to be purchased under long-term commitments. Georgia Power has commitments, in the form of capacity purchases, regarding a portion of a 5% interest in the original cost of Plant Vogtle Units 1 and 2 owned by MEAG Power that are in effect until the later of the retirement of the plant or the latest stated maturity date of MEAG Power's bonds issued to finance such ownership interest. The payments for capacity are required whether or not any capacity is available. Portions of the capacity payments made to MEAG Power for its Plant Vogtle Units 1 and 2 investment relate to costs in excess of Georgia Power's allowed investment for ratemaking purposes. The present value of these portions at the time of the disallowance was written off. Generally, the cost of such capacity is included in purchased power in Southern Company's statements of income and in purchased power, non-affiliates in Georgia Power's statements of income. Georgia Power's capacity payments related to this commitment totaled $4 million, $6 million, and $5 million in 2022, 2021, and 2020, respectively. At December 31, 2022, Georgia Power's estimated long-term obligations related to this commitment totaled $41 million, consisting of $3 million for 2023, $4 million annually for 2024 and 2025, $2 million annually for 2026 and 2027, and $26 million thereafter. See Note 9 for information regarding PPAs accounted for as leases. Southern Company Gas has commitments for pipeline charges, storage capacity, and gas supply, including charges recoverable through natural gas cost recovery mechanisms or, alternatively, billed to marketers selling retail natural gas. Gas supply commitments include amounts for gas commodity purchases associated with Nicor Gas and SouthStar of 34 million mmBtu at floating gas prices calculated using forward natural gas prices at December 31, 2022 and valued at $157 million. Southern Company Gas provides guarantees to certain gas suppliers for certain of its subsidiaries in support of payment obligations. Southern Company Gas' expected future contractual obligations for pipeline charges, storage capacity, and gas supply that are not recognized on the balance sheets at December 31, 2022 were as follows: Pipeline Charges, Storage Capacity, and Gas Supply (in millions) 2023 $ 637 2024 455 2025 390 2026 212 2027 134 Thereafter 871 Total $ 2,699 Guarantees SCS may enter into various types of wholesale energy and natural gas contracts acting as an agent for the traditional electric operating companies and Southern Power. Under these agreements, each of the traditional electric operating companies and Southern Power may be jointly and severally liable. Accordingly, Southern Company has entered into keep-well agreements with each of the traditional electric operating companies to ensure they will not subsidize or be responsible for any costs, losses, liabilities, or damages resulting from the inclusion of Southern Power as a contracting party under these agreements. Alabama Power has guaranteed a $100 million principal amount long-term bank loan SEGCO entered into in 2018 and subsequently extended and amended. Georgia Power has agreed to reimburse Alabama Power for the portion of such obligation corresponding to Georgia Power's proportionate ownership of SEGCO's stock if Alabama Power is called upon to make such payment under its guarantee. At December 31, 2022, the capitalization of SEGCO consisted of $80 million of equity and $100 million of long-term debt that matures in November 2024, on which the annual interest requirement is derived from a variable rate index. In addition, SEGCO had short-term debt outstanding of $17 million. See Note 7 under "SEGCO" for additional information. As discussed in Note 9, Alabama Power and Georgia Power have entered into certain residual value guarantees related to railcar leases.

REVENUE FROM CONTRACTS WITH CUS

REVENUE FROM CONTRACTS WITH CUSTOMERS	12 Months Ended
	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
REVENUE FROM CONTRACTS WITH CUSTOMERS	REVENUE FROM CONTRACTS WITH CUSTOMERS The Registrants generate revenues from a variety of sources, some of which are not accounted for as revenue from contracts with customers, such as leases, derivatives, and certain cost recovery mechanisms. See Note 1 under "Revenues" for additional information on the revenue policies of the Registrants. See Notes 9 and 14 for additional information on revenue accounted for under lease and derivative accounting guidance, respectively. The following table disaggregates revenue from contracts with customers for the periods presented: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) 2022 Operating revenues Retail electric revenues Residential $ 6,604 $ 2,638 $ 3,664 $ 302 $ — $ — Commercial 5,369 1,685 3,385 299 — — Industrial 3,764 1,507 1,921 336 — — Other 102 14 79 9 — — Total retail electric revenues 15,839 5,844 9,049 946 — — Natural gas distribution revenues Residential 2,843 — — — — 2,843 Commercial 763 — — — — 763 Transportation 1,186 — — — — 1,186 Industrial 84 — — — — 84 Other 342 — — — — 342 Total natural gas distribution revenues 5,218 — — — — 5,218 Wholesale electric revenues PPA energy revenues 2,274 489 130 16 1,673 — PPA capacity revenues 596 194 47 4 356 — Non-PPA revenues 250 200 30 690 740 — Total wholesale electric revenues 3,120 883 207 710 2,769 — Other natural gas revenues Gas marketing services 636 — — — — 636 Other natural gas revenues 51 — — — — 51 Total natural gas revenues 687 — — — — 687 Other revenues 1,077 194 446 47 36 — Total revenue from contracts with customers 25,941 6,921 9,702 1,703 2,805 5,905 Other revenue sources (a) 3,338 896 1,882 (9) 564 57 Total operating revenues $ 29,279 $ 7,817 $ 11,584 $ 1,694 $ 3,369 $ 5,962 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) 2021 Operating revenues Retail electric revenues Residential $ 6,207 $ 2,467 $ 3,471 $ 269 $ — $ — Commercial 4,877 1,600 3,010 267 — — Industrial 3,067 1,386 1,391 290 — — Other 93 17 68 8 — — Total retail electric revenues 14,244 5,470 7,940 834 — — Natural gas distribution revenues Residential 1,799 — — — — 1,799 Commercial 470 — — — — 470 Transportation 1,038 — — — — 1,038 Industrial 49 — — — — 49 Other 269 — — — — 269 Total natural gas distribution revenues 3,625 — — — — 3,625 Wholesale electric revenues PPA energy revenues 1,122 184 95 11 854 — PPA capacity revenues 493 115 55 5 323 — Non-PPA revenues 236 170 21 401 398 — Total wholesale electric revenues 1,851 469 171 417 1,575 — Other natural gas revenues Wholesale gas services 2,168 — — — — 2,168 Gas marketing services 464 — — — — 464 Other natural gas revenues 36 — — — — 36 Total other natural gas revenues 2,668 — — — — 2,668 Other revenues 1,075 202 452 31 30 — Total revenue from contracts with customers 23,463 6,141 8,563 1,282 1,605 6,293 Other revenue sources (a) 3,349 272 697 40 611 1,786 Other adjustments (b) (3,699) — — — — (3,699) Total operating revenues $ 23,113 $ 6,413 $ 9,260 $ 1,322 $ 2,216 $ 4,380 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) 2020 Operating revenues Retail electric revenues Residential $ 6,113 $ 2,377 $ 3,476 $ 260 $ — $ — Commercial 4,699 1,512 2,933 254 — — Industrial 2,775 1,293 1,197 285 — — Other 90 21 60 9 — — Total retail electric revenues 13,677 5,203 7,666 808 — — Natural gas distribution revenues Residential 1,338 — — — — 1,338 Commercial 340 — — — — 340 Transportation 971 — — — — 971 Industrial 30 — — — — 30 Other 209 — — — — 209 Total natural gas distribution revenues 2,888 — — — — 2,888 Wholesale electric revenues PPA energy revenues 735 133 42 9 570 — PPA capacity revenues 454 108 50 3 296 — Non-PPA revenues 210 43 10 311 239 — Total wholesale electric revenues 1,399 284 102 323 1,105 — Other natural gas revenues Wholesale gas services 1,727 — — — — 1,727 Gas marketing services 391 — — — — 391 Other natural gas revenues 33 — — — — 33 Total other natural gas revenues 2,151 — — — — 2,151 Other revenues 982 159 447 26 14 — Total revenue from contracts with customers 21,097 5,646 8,215 1,157 1,119 5,039 Other revenue sources (a) 3,764 184 94 15 614 2,881 Other adjustments (b) (4,486) — — — — (4,486) Total operating revenues $ 20,375 $ 5,830 $ 8,309 $ 1,172 $ 1,733 $ 3,434 (a) Other revenue sources relate to revenues from customers accounted for as derivatives and leases, alternative revenue programs at Southern Company Gas, and cost recovery mechanisms and revenues that meet other scope exceptions for revenues from contracts with customers at the traditional electric operating companies. (b) Other adjustments relate to the cost of Southern Company Gas' energy and risk management activities. Wholesale gas services revenues are presented net of the related costs of those activities on the statement of income. See Notes 15 and 16 under "Southern Company Gas" for information on the sale of Sequent and components of wholesale gas services' operating revenues, respectively. Contract Balances The following table reflects the closing balances of receivables, contract assets, and contract liabilities related to revenues from contracts with customers at December 31, 2022 and 2021: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Accounts Receivable At December 31, 2022 $ 3,123 $ 696 $ 922 $ 92 $ 237 $ 1,107 At December 31, 2021 2,504 589 736 73 149 753 Contract Assets At December 31, 2022 $ 156 $ 2 $ 89 $ — $ — $ — At December 31, 2021 117 2 63 — 1 — Contract Liabilities At December 31, 2022 $ 45 $ 4 $ 9 $ — $ 1 $ — At December 31, 2021 57 4 14 — 1 — At December 31, 2022 and 2021, Georgia Power had contract assets primarily related to retail customer fixed bill programs, where the payment is contingent upon Georgia Power's continued performance and the customer's continued participation in the program over a one-year contract term, and unregulated service agreements, where payment is contingent on project completion. Contract liabilities for Georgia Power relate to cash collections recognized in advance of revenue for unregulated service agreements. Southern Company's unregulated distributed generation business had contract assets of $65 million and $50 million at December 31, 2022 and 2021, respectively, and contract liabilities of $32 million and $39 million at December 31, 2022 and 2021, respectively, for outstanding performance obligations. Revenues recognized in 2022 and 2021, which were included in contract liabilities at December 31, 2021 and December 31, 2020, respectively, were $36 million and $29 million, respectively, for Southern Company and immaterial for the other Registrants. Remaining Performance Obligations The Subsidiary Registrants have long-term contracts with customers in which revenues are recognized as performance obligations are satisfied over the contract term. For the traditional electric operating companies and Southern Power, these contracts primarily relate to PPAs whereby electricity and generation capacity are provided to a customer. The revenue recognized for the delivery of electricity is variable; however, certain PPAs include a fixed payment for fixed generation capacity over the term of the contract. For Southern Company Gas, these contracts involve energy infrastructure enhancement and upgrade projects for certain governmental customers. Southern Company's unregulated distributed generation business also has partially satisfied performance obligations related to certain fixed price contracts. Revenues from contracts with customers related to these performance obligations remaining at December 31, 2022 are expected to be recognized as follows: 2023 2024 2025 2026 2027 Thereafter (in millions) Southern Company $ 640 $ 483 $ 332 $ 311 $ 315 $ 2,076 Alabama Power 24 7 6 — — — Georgia Power 74 39 22 11 10 10 Southern Power 355 345 302 303 310 2,077 Southern Company Gas 34 29 — — — — Revenue expected to be recognized for performance obligations remaining at December 31, 2022 was immaterial for Mississippi Power.

PROPERTY, PLANT, AND EQUIPMENT

PROPERTY, PLANT, AND EQUIPMENT	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT, AND EQUIPMENT	PROPERTY, PLANT, AND EQUIPMENT Property, plant, and equipment is stated at original cost or fair value at acquisition, as appropriate, less any regulatory disallowances and impairments. Original cost may include: materials; labor; minor items of property; appropriate administrative and general costs; payroll-related costs such as taxes, pensions, and other benefits; and the interest capitalized and/or cost of equity funds used during construction. The Registrants' property, plant, and equipment in service consisted of the following at December 31, 2022 and 2021: At December 31, 2022: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Electric utilities: Generation $ 51,756 $ 15,920 $ 17,755 $ 2,826 $ 14,619 $ — Transmission 14,201 5,658 7,576 927 — — Distribution 24,200 9,154 13,819 1,228 — — General/other 5,806 2,740 2,729 273 39 — Electric utilities' plant in service 95,963 33,472 41,879 5,254 14,658 — Southern Company Gas: Natural gas distribution utilities transportation and distribution 16,810 — — — — 16,810 Storage facilities 1,553 — — — — 1,553 Other 1,360 — — — — 1,360 Southern Company Gas plant in service 19,723 — — — — 19,723 Other plant in service 1,843 — — — — — Total plant in service $ 117,529 $ 33,472 $ 41,879 $ 5,254 $ 14,658 $ 19,723 At December 31, 2021: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Electric utilities: Generation $ 53,803 $ 16,631 $ 19,184 $ 2,791 $ 14,551 $ — Transmission 13,406 5,334 7,132 900 — — Distribution 22,236 8,643 12,437 1,156 — — General/other 5,423 2,527 2,579 259 34 — Electric utilities' plant in service 94,868 33,135 41,332 5,106 14,585 — Southern Company Gas: Natural gas distribution utilities transportation and distribution 15,714 — — — — 15,714 Storage facilities 1,315 — — — — 1,315 Other 1,851 — — — — 1,851 Southern Company Gas plant in service 18,880 — — — — 18,880 Other plant in service 1,844 — — — — — Total plant in service $ 115,592 $ 33,135 $ 41,332 $ 5,106 $ 14,585 $ 18,880 The cost of replacements of property, exclusive of minor items of property, is capitalized. The cost of maintenance, repairs, and replacement of minor items of property is charged to other operations and maintenance expenses as incurred or performed with the exception of nuclear refueling costs and certain maintenance costs including those described below. In accordance with orders from their respective state PSCs, Alabama Power and Georgia Power defer nuclear refueling outage operations and maintenance expenses to a regulatory asset when the charges are incurred. Alabama Power amortizes the costs over a subsequent 18-month period with Plant Farley's fall outage cost amortization beginning in January of the following year and spring outage cost amortization beginning in July of the same year. Georgia Power amortizes its costs over each unit's operating cycle, or 18 months for Plant Vogtle Units 1 and 2 and 24 months for Plant Hatch Units 1 and 2. Georgia Power's amortization period begins the month the refueling outage starts. A portion of Mississippi Power's railway track maintenance costs is charged to fuel stock and recovered through Mississippi Power's fuel clause. The portion of Southern Company Gas' non-working gas used to maintain the structural integrity of natural gas storage facilities that is considered to be non-recoverable is depreciated, while the recoverable or retained portion is not depreciated. See Note 9 for information on finance lease right-of-use (ROU) assets, net, which are included in property, plant, and equipment. The Registrants have deferred certain implementation costs related to cloud hosting arrangements. At December 31, 2022 and 2021, deferred cloud implementation costs, net of amortization, which are generally included in other deferred charges and assets on the Registrants' balance sheets, are as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Deferred cloud implementation costs, net: At December 31, 2022 $ 345 $ 81 $ 108 $ 14 $ 18 $ 54 At December 31, 2021 240 54 81 11 14 35 Once a hosted software is placed into service, the related deferred costs are amortized on a straight-line basis over the remaining expected hosting arrangement term, including any renewal options that are reasonably certain of exercise. The amortization is reflected with the associated cloud hosting fees, which are generally reflected in other operations and maintenance expenses on the Registrants' statements of income. In 2022, amortization of deferred cloud implementation costs recognized was $29 million for Southern Company, $8 million for Alabama Power, $12 million for Georgia Power, and immaterial for the other Registrants. In 2021, amortization from deferred cloud implementation costs was immaterial for all Registrants. See Note 2 under "Regulatory Assets and Liabilities," "Alabama Power – Software Accounting Order," and "Mississippi Power – Software Accounting Order" for information on deferrals of certain other operations and maintenance costs associated with software and cloud computing projects by the traditional electric operating companies and natural gas distribution utilities, as authorized by their respective state PSCs or applicable state regulatory agencies. Depreciation and Amortization The traditional electric operating companies' and Southern Company Gas' depreciation of the original cost of utility plant in service is provided primarily by using composite straight-line rates. The approximate rates for 2022, 2021, and 2020 are as follows: 2022 2021 2020 Alabama Power 2.7 % 2.7 % 2.6 % Georgia Power 3.3 % 3.3 % 3.0 % Mississippi Power 3.4 % 3.6 % 3.7 % Southern Company Gas 2.7 % 2.8 % 2.8 % Depreciation studies are conducted periodically to update the composite rates. These studies are filed with the respective state PSC and/or other applicable state and federal regulatory agencies for the traditional electric operating companies and the natural gas distribution utilities. Effective April 1, 2020, Mississippi Power's depreciation rates were revised. Effective January 1, 2023, Alabama Power's and Georgia Power's depreciation rates were revised. See Note 2 for additional information. When property, plant, and equipment subject to composite depreciation is retired or otherwise disposed of in the normal course of business, its original cost, together with the cost of removal, less salvage, is charged to accumulated depreciation. For other property dispositions, the applicable cost and accumulated depreciation are removed from the balance sheet accounts, and a gain or loss is recognized. Minor items of property included in the original cost of the asset are retired when the related property unit is retired. At December 31, 2022 and 2021, accumulated depreciation for Southern Company and Southern Company Gas consisted of utility plant in service totaling $34.3 billion and $33.1 billion, respectively, for Southern Company and $5.1 billion and $4.8 billion, respectively, for Southern Company Gas, as well as other plant in service totaling $963 million and $930 million, respectively, for Southern Company and $184 million and $219 million, respectively, for Southern Company Gas. Other plant in service includes the non-utility assets of Southern Company Gas, as well as, for Southern Company, certain other non-utility subsidiaries. Depreciation of the original cost of other plant in service is provided primarily on a straight-line basis over estimated useful lives. Useful lives for Southern Company Gas's non-utility assets range from five Southern Power Southern Power applies component depreciation, where depreciation is computed principally by the straight-line method over the estimated useful life of the asset. Certain of Southern Power's generation assets related to natural gas-fired facilities are depreciated on a units-of-production basis, using hours or starts, to better match outage and maintenance costs to the usage of, and revenues from, these assets. The primary assets in Southern Power's property, plant, and equipment are generating facilities, which generally have estimated useful lives as follows: Southern Power Generating Facility Useful life Natural gas Up to 50 years Solar Up to 35 years Wind Up to 35 years (*) (*) Effective January 1, 2022, Southern Power revised the depreciable lives of its wind generating facilities from up to 30 years to up to 35 years. This revision resulted in an immaterial decrease in depreciation for 2022. When Southern Power's depreciable property, plant, and equipment is retired, or otherwise disposed of in the normal course of business, the applicable cost and accumulated depreciation is removed and a gain or loss is recognized in the statements of income. Southern Power reviews its estimated useful lives and salvage values on an ongoing basis. The results of these reviews could result in changes which could have a material impact on Southern Power's net income. Joint Ownership Agreements At December 31, 2022, the Registrants' percentage ownership and investment (exclusive of nuclear fuel) in jointly-owned facilities in commercial operation were as follows: Facility (Type) Percent Plant in Service Accumulated CWIP (in millions) Alabama Power Greene County (natural gas) Units 1 and 2 60.0 % (a) $ 193 $ 85 $ — Plant Miller (coal) Units 1 and 2 91.8 (b) 2,148 712 13 Georgia Power Plant Hatch (nuclear) 50.1 % (c) $ 1,401 $ 671 $ 62 Plant Vogtle (nuclear) Units 1 and 2 45.7 (c) 3,628 2,298 94 Plant Scherer (coal) Units 1 and 2 8.4 (c) 276 106 1 Plant Scherer (coal) Unit 3 75.0 (c) 1,317 567 6 Rocky Mountain (pumped storage) 25.4 (d) 184 153 1 Mississippi Power Greene County (natural gas) Units 1 and 2 40.0 % (a) $ 125 $ 70 $ — Plant Daniel (coal) Units 1 and 2 50.0 (e) 765 257 30 Southern Company Gas Dalton Pipeline (natural gas pipeline) 50.0 % (f) $ 271 $ 23 $ — (a) Jointly owned by Alabama Power and Mississippi Power and operated and maintained by Alabama Power. (b) Jointly owned with PowerSouth and operated and maintained by Alabama Power. (c) Georgia Power owns undivided interests in Plants Hatch, Vogtle Units 1 and 2, and Scherer in varying amounts jointly with one or more of the following entities: OPC, MEAG Power, Dalton, FP&L, and JEA. Georgia Power has been contracted to operate and maintain the plants as agent for the co-owners and is jointly and severally liable for third party claims related to these plants. (d) Jointly owned with OPC, which is the operator of the plant. (e) Jointly owned by FP&L and Mississippi Power. In accordance with the operating agreement, Mississippi Power acts as FP&L's agent with respect to the operation and maintenance of these units. See Note 3 under "Other Matters – Mississippi Power – Plant Daniel" for additional information. (f) Jointly owned with The Williams Companies, Inc., the Dalton Pipeline is a 115-mile natural gas pipeline that serves as an extension of the Transcontinental Gas Pipe Line Company, LLC pipeline system into northwest Georgia. Southern Company Gas leases its 50% undivided ownership for approximately $26 million annually through 2042. The lessee is responsible for maintaining the pipeline during the lease term and for providing service to transportation customers under its FERC-regulated tariff. Georgia Power currently holds a 45.7% ownership interest in Plant Vogtle Units 3 and 4, which are under construction and had a CWIP balance of $9.7 billion at December 31, 2022, excluding charges recorded in 2018, 2020, 2021, and 2022 for the estimated probable loss associated with construction. See Note 2 under "Georgia Power – Nuclear Construction" for additional information. The Registrants' proportionate share of their jointly-owned facility operating expenses is included in the corresponding operating expenses in the statements of income and each Registrant is responsible for providing its own financing. Assets Subject to Lien Mississippi Power provides retail service to its largest retail customer, Chevron Products Company (Chevron), at its refinery in Pascagoula, Mississippi through at least 2038 in accordance with agreements approved by the Mississippi PSC. The agreements grant Chevron a security interest in the co-generation assets located at the refinery and owned by Mississippi Power, with a lease receivable balance of $157 million at December 31, 2022, that is exercisable upon the occurrence of (i) certain bankruptcy events or (ii) other events of default coupled with specific reductions in steam output at the facility and a downgrade of Mississippi Power's credit rating to below investment grade by two of the three rating agencies. See Note 9 under "Lessor" for additional information. See Note 8 under "Long-term Debt" for information regarding debt secured by certain assets of Georgia Power and Southern Company Gas.

ASSET RETIREMENT OBLIGATIONS

ASSET RETIREMENT OBLIGATIONS	12 Months Ended
	Dec. 31, 2022
Asset Retirement Obligation Disclosure [Abstract]
ASSET RETIREMENT OBLIGATIONS	ASSET RETIREMENT OBLIGATIONS AROs are computed as the present value of the estimated costs for an asset's future retirement and are recorded in the period in which the liability is incurred. The estimated costs are capitalized as part of the related long-lived asset and depreciated over the asset's useful life. In the absence of quoted market prices, AROs are estimated using present value techniques in which estimates of future cash outlays associated with the asset retirements are discounted using a credit-adjusted risk-free rate. Estimates of the timing and amounts of future cash outlays are based on projections of when and how the assets will be retired and the cost of future removal activities. Each traditional electric operating company and natural gas distribution utility has received accounting guidance from its state PSC or applicable state regulatory agency allowing the continued accrual or recovery of other retirement costs for long-lived assets that it does not have a legal obligation to retire. Accordingly, the accumulated removal costs for these obligations are reflected in the balance sheets as regulatory liabilities and amounts to be recovered are reflected in the balance sheets as regulatory assets. The ARO liabilities for the traditional electric operating companies primarily relate to facilities that are subject to the CCR Rule and the related state rules, principally ash ponds. In addition, Alabama Power and Georgia Power have retirement obligations related to the decommissioning of nuclear facilities (Alabama Power's Plant Farley and Georgia Power's ownership interests in Plant Hatch and Plant Vogtle Units 1 and 2). See "Nuclear Decommissioning" herein for additional information. Other significant AROs include various landfill sites and asbestos removal for Alabama Power, Georgia Power, and Mississippi Power and gypsum cells and mine reclamation for Mississippi Power. The ARO liability for Southern Power primarily relates to its solar and wind facilities, which are located on long-term land leases requiring the restoration of land at the end of the lease. The traditional electric operating companies and Southern Company Gas also have identified other retirement obligations, such as obligations related to certain electric transmission and distribution facilities, certain asbestos-containing material within long-term assets not subject to ongoing repair and maintenance activities, certain wireless communication towers, the disposal of polychlorinated biphenyls in certain transformers, leasehold improvements, equipment on customer property, and property associated with the Southern Company system's rail lines and natural gas pipelines. However, liabilities for the removal of these assets have not been recorded because the settlement timing for certain retirement obligations related to these assets is indeterminable and, therefore, the fair value of the retirement obligations cannot be reasonably estimated. A liability for these retirement obligations will be recognized when sufficient information becomes available to support a reasonable estimation of the ARO. Southern Company and the traditional electric operating companies will continue to recognize in their respective statements of income allowed removal costs in accordance with regulatory treatment. Any differences between costs recognized in accordance with accounting standards related to asset retirement and environmental obligations and those reflected in rates are recognized as either a regulatory asset or liability in the balance sheets as ordered by the various state PSCs. Details of the AROs included in the balance sheets are as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power (*) (in millions) Balance at December 31, 2020 $ 10,684 $ 3,974 $ 6,265 $ 176 $ 95 Liabilities incurred 26 — 3 — 23 Liabilities settled (456) (202) (210) (24) — Accretion 407 156 236 7 5 Cash flow revisions 1,026 406 530 31 8 Balance at December 31, 2021 $ 11,687 $ 4,334 $ 6,824 $ 190 $ 131 Liabilities incurred 36 — 35 — — Liabilities settled (455) (205) (212) (20) — Accretion 406 158 231 6 6 Cash flow revisions (834) — (844) 3 7 Balance at December 31, 2022 $ 10,840 $ 4,287 $ 6,034 $ 179 $ 144 (*) Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets. During 2021, Alabama Power recorded increases totaling approximately $406 million to its AROs primarily related to the CCR Rule and the related state rule based on updated estimates for post-closure costs at its ash ponds and inflation rates. During 2021, Georgia Power refined the cost estimates related to its plans to close the ash ponds at all of its generating plants in compliance with the CCR Rule and the related state rule, including updates to estimates for inflation rates and the timing of closure activities, and recorded an increase of approximately $435 million to its AROs related to the CCR Rule and the related state rule. In December 2022, Georgia Power recorded a net decrease of approximately $780 million to its AROs related to the CCR Rule and the related state rule resulting from changes in estimates, including lower future inflation rates, higher discount rates, and timing of closure activities, as well as a change in closure methodology for one ash pond as approved in Georgia Power's 2022 IRP. See Note 2 under "Georgia Power – Integrated Resource Plans" for additional information. During 2021, Mississippi Power recorded an increase of approximately $31 million to its AROs related to the CCR Rule based on updated estimates for the timing of closure activities, post-closure costs at one of its ash ponds, and inflation rates. The cost estimates for AROs related to the disposal of CCR are based on information at December 31, 2022 using various assumptions related to closure and post-closure costs, timing of future cash outlays, inflation and discount rates, and the potential methods for complying with the CCR Rule and the related state rules. The traditional electric operating companies have periodically updated, and expect to continue periodically updating, their related cost estimates and ARO liabilities for each CCR unit as additional information related to these assumptions becomes available. Some of these updates have been, and future updates may be, material. The cost estimates for Alabama Power and Mississippi Power are based on closure-in-place for all ash ponds. The cost estimates for Georgia Power are based on a combination of closure-in-place for some ash ponds and closure by removal for others. Additionally, the closure designs and plans in the States of Alabama and Georgia are subject to approval by environmental regulatory agencies. Absent continued recovery of ARO costs through regulated rates, results of operations, cash flows, and financial condition for Southern Company and the traditional electric operating companies could be materially impacted. The ultimate outcome of these matters cannot be determined at this time. Nuclear Decommissioning The NRC requires licensees of commercial nuclear power reactors to establish a plan for providing reasonable assurance of funds for future decommissioning. Alabama Power and Georgia Power have external trust funds (Funds) to comply with the NRC's regulations. Use of the Funds is restricted to nuclear decommissioning activities. The Funds are managed and invested in accordance with applicable requirements of various regulatory bodies, including the NRC, the FERC, and state PSCs, as well as the IRS. While Alabama Power and Georgia Power are allowed to prescribe an overall investment policy to the Funds' managers, neither Southern Company nor its subsidiaries or affiliates are allowed to engage in the day-to-day management of the Funds or to mandate individual investment decisions. Day-to-day management of the investments in the Funds is delegated to unrelated third-party managers with oversight by the management of Alabama Power and Georgia Power. The Funds' managers are authorized, within certain investment guidelines, to actively buy and sell securities at their own discretion in order to maximize the return on the Funds' investments. The Funds are invested in a tax-efficient manner in a diversified mix of equity and fixed income securities and are reported as trading securities. Alabama Power and Georgia Power record the investment securities held in the Funds at fair value, as disclosed in Note 13, as management believes that fair value best represents the nature of the Funds. Gains and losses, whether realized or unrealized, are recorded in the regulatory liability for AROs in the balance sheets and are not included in net income or OCI. Fair value adjustments and realized gains and losses are determined on a specific identification basis. The Funds at Georgia Power participate in a securities lending program through the managers of the Funds. Under this program, Georgia Power's Funds' investment securities are loaned to institutional investors for a fee. Securities loaned are fully collateralized by cash, letters of credit, and/or securities issued or guaranteed by the U.S. government or its agencies or instrumentalities. At December 31, 2022 and 2021, approximately $35 million and $42 million, respectively, of the fair market value of Georgia Power's Funds' securities were on loan and pledged to creditors under the Funds' managers' securities lending program. The fair value of the collateral received was approximately $36 million and $43 million at December 31, 2022 and 2021, respectively, and can only be sold by the borrower upon the return of the loaned securities. The collateral received is treated as a non-cash item in the statements of cash flows. Investment securities in the Funds for December 31, 2022 and 2021 were as follows: Southern Company Alabama Georgia (in millions) At December 31, 2022: Equity securities $ 1,095 $ 690 $ 405 Debt securities 838 267 571 Other securities 210 168 42 Total investment securities in the Funds $ 2,143 $ 1,125 $ 1,018 At December 31, 2021: Equity securities $ 1,358 $ 849 $ 509 Debt securities 986 316 670 Other securities 197 159 38 Total investment securities in the Funds $ 2,541 $ 1,324 $ 1,217 These amounts exclude receivables related to investment income and pending investment sales and payables related to pending investment purchases. For Southern Company and Georgia Power, these amounts include Georgia Power's investment securities pledged to creditors and collateral received and excludes payables related to Georgia Power's securities lending program. The fair value increases (decreases) of the Funds, including unrealized gains (losses) and reinvested interest and dividends and excluding the Funds' expenses, for 2022, 2021, and 2020 are shown in the table below. Southern Company Alabama Georgia (in millions) Fair value increases (decreases) 2022 $ (360) $ (171) $ (189) 2021 274 200 74 2020 280 142 138 Unrealized gains (losses) At December 31, 2022 $ (391) $ (204) $ (187) At December 31, 2021 (27) (30) 3 At December 31, 2020 220 121 99 The investment securities held in the Funds continue to be managed with a long-term focus. Accordingly, all purchases and sales within the Funds are presented separately in the statements of cash flows as investing cash flows, consistent with the nature of the securities and purpose for which the securities were acquired. For Alabama Power, approximately $14 million and $15 million at December 31, 2022 and 2021, respectively, previously recorded in internal reserves is being transferred into the Funds through 2040 as approved by the Alabama PSC. The NRC's minimum external funding requirements are based on a generic estimate of the cost to decommission only the radioactive portions of a nuclear unit based on the size and type of reactor. Alabama Power and Georgia Power have filed plans with the NRC designed to ensure that, over time, the deposits and earnings of the Funds will provide the minimum funding amounts prescribed by the NRC. At December 31, 2022 and 2021, the accumulated provisions for the external decommissioning trust funds were as follows: 2022 2021 (in millions) Alabama Power Plant Farley $ 1,125 $ 1,324 Georgia Power Plant Hatch $ 628 $ 757 Plant Vogtle Units 1 and 2 382 460 Plant Vogtle Unit 3 8 — Total $ 1,018 $ 1,217 Site study cost is the estimate to decommission a specific facility as of the site study year. The decommissioning cost estimates are based on prompt dismantlement and removal of the plant from service. The actual decommissioning costs may vary from these estimates because of changes in the assumed date of decommissioning, changes in NRC requirements, or changes in the assumptions used in making these estimates. The estimated costs of decommissioning at December 31, 2022 based on the most current studies, which were performed in 2018 for Alabama Power and in 2021 for Georgia Power, were as follows: Plant Plant Hatch (*) Plant Vogtle Units 1 and 2 (*) Decommissioning periods: Beginning year 2037 2034 2047 Completion year 2076 2075 2079 (in millions) Site study costs: Radiated structures $ 1,234 $ 771 $ 628 Spent fuel management 387 186 170 Non-radiated structures 99 61 85 Total site study costs $ 1,720 $ 1,018 $ 883 (*) Based on Georgia Power's ownership interests. For ratemaking purposes, Alabama Power's decommissioning costs are based on the site study and Georgia Power's decommissioning costs are based on the NRC generic estimate to decommission the radioactive portion of the facilities and the site study estimate for spent fuel management as of 2021. Significant assumptions used to determine these costs for ratemaking were an estimated inflation rate of 4.5% and 2.5% for Alabama Power and Georgia Power, respectively, and an estimated trust earnings rate of 7.0% and 4.5% for Alabama Power and Georgia Power, respectively. The next site study for Alabama Power is expected to be completed later in 2023. Alabama Power's site-specific estimates of decommissioning costs for Plant Farley are updated every five years. Projections of funds are reviewed with the Alabama PSC to ensure that, over time, the deposits and earnings of the Funds will provide adequate funding to cover the site-specific costs. If necessary, Alabama Power would seek the Alabama PSC's approval to address any changes in a manner consistent with NRC and other applicable requirements. Under the 2019 ARP, Georgia Power's annual decommissioning cost for ratemaking was a total of $4 million for Plant Hatch and Plant Vogtle Units 1 and 2. Effective January 1, 2023, as approved in the 2022 ARP, there is no annual decommissioning cost for ratemaking. Any funding amount required by the NRC during the period covered by the 2022 ARP will be deferred to a regulatory asset and recovery is expected to be determined in Georgia Power's next base rate case. See Note 2 under "Georgia Power – Rate Plans – 2022 ARP" for additional information.

CONSOLIDATED ENTITIES AND EQUIT

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS	12 Months Ended
	Dec. 31, 2022
Equity Method Investments and Joint Ventures [Abstract]
CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS	CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTSThe Registrants may hold ownership interests in a number of business ventures with varying ownership structures. Partnership interests and other variable interests are evaluated to determine if each entity is a VIE. If a venture is a VIE for which a Registrant is the primary beneficiary, the assets, liabilities, and results of operations of the entity are consolidated. The Registrants reassess the conclusion as to whether an entity is a VIE upon certain occurrences, which are deemed reconsideration events. For entities that are not determined to be VIEs, the Registrants evaluate whether they have control or significant influence over the investee to determine the appropriate consolidation and presentation. Generally, entities under the control of a Registrant are consolidated, and entities over which a Registrant can exert significant influence, but which a Registrant does not control, are accounted for under the equity method of accounting. Investments accounted for under the equity method are recorded within equity investments in unconsolidated subsidiaries in the balance sheets and, for Southern Company and Southern Company Gas, the equity income is recorded within earnings from equity method investments in the statements of income. See "SEGCO" and "Southern Company Gas" herein for additional information. Southern Company At December 31, 2022 and 2021, Southern Holdings had equity method investments totaling $112 million and $101 million, respectively, primarily related to investments in venture capital funds focused on energy and utility investments. Earnings from these investments were immaterial for all periods presented. SEGCO Alabama Power and Georgia Power own equally all of the outstanding capital stock of SEGCO, which owns electric generating units with a total rated capacity of 1,020 MWs, as well as associated transmission facilities. Retirement of SEGCO's generating units is expected to occur by December 31, 2028. Alabama Power and Georgia Power account for SEGCO using the equity method; Southern Company consolidates SEGCO. The capacity of these units is sold equally to Alabama Power and Georgia Power. Alabama Power and Georgia Power make payments sufficient to provide for the operating expenses, taxes, interest expense, and a ROE. The share of purchased power included in purchased power, affiliates in the statements of income totaled $124 million in 2022, $75 million in 2021, and $67 million in 2020 for Alabama Power and $127 million in 2022, $77 million in 2021, and $69 million in 2020 for Georgia Power. SEGCO paid dividends of $14 million in 2022, $14 million in 2021, and $12 million in 2020, one half of which were paid to each of Alabama Power and Georgia Power. In addition, Alabama Power and Georgia Power each recognize 50% of SEGCO's net income. Alabama Power, which owns and operates a generating unit adjacent to the SEGCO generating units, has a joint ownership agreement with SEGCO for the ownership of an associated gas pipeline. Alabama Power owns 14% of the pipeline with the remaining 86% owned by SEGCO. See Note 3 under "Guarantees" for additional information regarding guarantees of Alabama Power and Georgia Power related to SEGCO. Southern Power Variable Interest Entities Southern Power has certain subsidiaries that are determined to be VIEs. Southern Power is considered the primary beneficiary of these VIEs because it controls the most significant activities of the VIEs, including operating and maintaining the respective assets, and has the obligation to absorb expected losses of these VIEs to the extent of its equity interests. SP Solar and SP Wind SP Solar is owned by Southern Power and Global Atlantic Financial Group Limited (Global Atlantic). A wholly-owned subsidiary of Southern Power is the general partner and holds a 1% ownership interest, and another wholly-owned subsidiary of Southern Power owns a 66% ownership interest. Global Atlantic is the limited partner and holds the remaining 33% noncontrolling interest. SP Solar qualifies as a VIE since the arrangement is structured as a limited partnership and the 33% limited partner does not have substantive kick-out rights against the general partner. At December 31, 2022 and 2021, SP Solar had total assets of $5.9 billion and $6.1 billion, respectively, total liabilities of $0.4 billion, and noncontrolling interests of $1.1 billion. Cash distributions from SP Solar are allocated 67% to Southern Power and 33% to Global Atlantic in accordance with their partnership interest percentage. Under the terms of the limited partnership agreement, distributions without limited partner consent are limited to available cash and SP Solar is obligated to distribute all such available cash to its partners each quarter. Available cash includes all cash generated in the quarter subject to the maintenance of appropriate operating reserves. SP Wind is owned by Southern Power and three financial investors. A wholly-owned subsidiary of Southern Power owns 100% of the Class B membership interests and the three financial investors own 100% of the Class A membership interests. SP Wind qualifies as a VIE since the structure of the arrangement is similar to a limited partnership and the Class A members do not have substantive kick-out rights against Southern Power. At December 31, 2022 and 2021, SP Wind had total assets of $2.2 billion and $2.3 billion, respectively, total liabilities of $169 million and $130 million, respectively, and noncontrolling interests of $39 million and $41 million, respectively. Under the terms of the limited liability agreement, distributions without Class A member consent are limited to available cash and SP Wind is obligated to distribute all such available cash to its members each quarter. Available cash includes all cash generated in the quarter subject to the maintenance of appropriate operating reserves. Cash distributions from SP Wind are generally allocated 60% to Southern Power and 40% to the three financial investors in accordance with the limited liability agreement. Southern Power consolidates both SP Solar and SP Wind, as the primary beneficiary, since it controls the most significant activities of each entity, including operating and maintaining their assets. Certain transfers and sales of the assets in the VIEs are subject to partner consent and the liabilities are non-recourse to the general credit of Southern Power. Liabilities consist of customary working capital items and do not include any long-term debt. Other Variable Interest Entities Southern Power has other consolidated VIEs that relate to certain subsidiaries that have either sold noncontrolling interests to tax equity investors or acquired less than a 100% interest from facility developers. These entities are considered VIEs because the arrangements are structured similar to a limited partnership and the noncontrolling members do not have substantive kick-out rights. At December 31, 2022 and 2021, the other VIEs had total assets of $1.8 billion and $1.9 billion, respectively, total liabilities of $0.2 billion and $0.3 billion, respectively, and noncontrolling interests of $0.8 billion and $0.9 billion, respectively. Under the terms of the partnership agreements, distributions of all available cash are required each month or quarter and additional distributions require partner consent. Equity Method Investments At December 31, 2022 and 2021, Southern Power had equity method investments in wind and battery energy storage projects totaling $49 million and $86 million, respectively. Earnings (loss) from these investments were immaterial for all periods presented. During 2022, Southern Power sold equity method investments in wind projects and received proceeds totaling $38 million. The gains associated with the sales were immaterial. Subsequent to December 31, 2022, Southern Power sold its remaining equity method investments in wind and battery energy storage projects and received proceeds of $50 million. The gains associated with the transactions were immaterial. Southern Company Gas Equity Method Investments The carrying amounts of Southern Company Gas' equity method investments at December 31, 2022 and 2021 and related earnings (loss) from those investments for the years ended December 31, 2022, 2021, and 2020 were as follows: Investment Balance December 31, 2022 December 31, 2021 (in millions) SNG $ 1,243 $ 1,129 Other (*) 33 44 Total $ 1,276 $ 1,173 (*) Balance at December 31, 2022 reflects an $11 million distribution received in 2022 from PennEast Pipeline. Earnings (Loss) from Equity Method Investments 2022 2021 2020 (in millions) SNG $ 146 $ 127 $ 129 PennEast Pipeline (*) — (81) 7 Other 2 4 5 Total $ 148 $ 50 $ 141 (*) For 2021, includes pre-tax impairment charges totaling $84 million. See "PennEast Pipeline Project" herein for additional information, including the September 2021 cancellation of the project. For 2020, earnings primarily result from AFUDC equity recorded by the project entity. PennEast Pipeline Project In 2014, Southern Company Gas entered into a partnership in which it holds a 20% ownership interest in the PennEast Pipeline, an interstate pipeline company formed to develop and operate an approximate 118-mile natural gas pipeline between New Jersey and Pennsylvania. In 2019, an appellate court ruled that the PennEast Pipeline does not have federal eminent domain authority over lands in which a state has property rights interests. In June 2021, the U.S. Supreme Court ruled in favor of PennEast Pipeline following a review of the appellate court decision. Southern Company Gas assesses its equity method investments for impairment whenever events or changes in circumstances indicate that the investment may be impaired. Following the U.S. Supreme Court ruling, during the second quarter 2021, Southern Company Gas management reassessed the project construction timing, including the anticipated timing for receipt of a FERC certificate and all remaining state and local permits, as well as potential challenges thereto, and performed an impairment analysis. The outcome of the analysis resulted in a pre-tax impairment charge of $82 million ($58 million after tax). In September 2021, PennEast Pipeline announced that further development of the project was no longer supported, and, as a result, all further development of the project ceased. During the third quarter 2021, Southern Company Gas recorded an additional pre-tax charge of $2 million ($2 million after tax) related to its share of the project level impairment, as well as $7 million of additional tax expense, resulting in total pre-tax charges of $84 million ($67 million after tax) during 2021 related to the project.

FINANCING

FINANCING	12 Months Ended
	Dec. 31, 2022
Debt Disclosure [Abstract]
FINANCING	FINANCING Long-term Debt Details of long-term debt at December 31, 2022 and 2021 are provided in the following table: At December 31, 2022 Balance Outstanding at Maturity Weighted Average 2022 2021 (in millions) Southern Company Senior notes (a) 2023-2052 3.87% $ 35,683 $ 33,120 Junior subordinated notes 2024-2081 4.58% 8,836 8,918 FFB loans (b) 2023-2044 2.88% 4,874 4,962 Revenue bonds (c) 2024-2062 3.25% 2,844 2,662 First mortgage bonds (d) 2023-2062 3.46% 2,275 2,100 Medium-term notes 2026-2027 7.03% 84 130 Other long-term debt 2024-2045 4.96% 167 270 Finance lease obligations (e) 314 215 Unamortized fair value adjustment 330 359 Unamortized debt premium (discount), net (193) (216) Unamortized debt issuance expenses (273) (243) Total long-term debt 54,941 52,277 Less: Amount due within one year 4,285 2,157 Total long-term debt excluding amount due within one year $ 50,656 $ 50,120 Alabama Power Senior notes 2023-2052 3.86% $ 9,675 $ 8,725 Revenue bonds (c) 2024-2038 3.44% 995 995 Other long-term debt 2026 5.62% 45 45 Finance lease obligations (e) 5 4 Unamortized debt premium (discount), net (18) (18) Unamortized debt issuance expenses (72) (64) Total long-term debt 10,630 9,687 Less: Amount due within one year 301 751 Total long-term debt excluding amount due within one year $ 10,329 $ 8,936 Georgia Power Senior notes 2023-2052 3.90% $ 7,925 $ 6,825 Junior subordinated notes 2077 5.00% 270 270 FFB loans (b) 2023-2044 2.88% 4,874 4,962 Revenue bonds (c) 2025-2062 3.13% 1,738 1,591 Other long-term debt — 125 Finance lease obligations (e) 238 136 Unamortized debt premium (discount), net (18) (11) Unamortized debt issuance expenses (117) (114) Total long-term debt 14,910 13,784 Less: Amount due within one year 901 675 Total long-term debt excluding amount due within one year $ 14,009 $ 13,109 At December 31, 2022 Balance Outstanding at Maturity Weighted Average 2022 2021 (in millions) Mississippi Power Senior notes 2024-2051 3.93% $ 1,425 $ 1,425 Revenue bonds (c) 2025-2052 3.55% 111 76 Finance lease obligations (e) 17 18 Unamortized debt premium (discount), net 2 2 Unamortized debt issuance expenses (10) (10) Total long-term debt 1,545 1,511 Less: Amount due within one year 1 1 Total long-term debt excluding amount due within one year $ 1,544 $ 1,510 Southern Power Senior notes (a) 2023-2046 3.92% $ 2,998 $ 3,711 Unamortized debt premium (discount), net (5) (6) Unamortized debt issuance expenses (14) (17) Total long-term debt 2,979 3,688 Less: Amount due within one year 290 679 Total long-term debt excluding amount due within one year $ 2,689 $ 3,009 Southern Company Gas Senior notes 2023-2051 4.08% $ 4,769 $ 4,348 First mortgage bonds (d) 2023-2062 3.46% 2,275 2,100 Medium-term notes 2026-2027 7.03% 84 130 Other long-term debt 2024-2045 3.81% 22 — Unamortized fair value adjustment 330 359 Unamortized debt premium (discount), net (8) (35) Unamortized debt issuance expenses (30) — Total long-term debt 7,442 6,902 Less: Amount due within one year 400 47 Total long-term debt excluding amount due within one year $ 7,042 $ 6,855 (a) Includes a fair value gain (loss) of $(31) million and $5 million at December 31, 2022 and 2021, respectively, related to Southern Power's foreign currency hedge on its euro-denominated senior notes. (b) Secured by a first priority lien on (i) Georgia Power's undivided ownership interest in Plant Vogtle Units 3 and 4 (primarily the units under construction, the related real property, and any nuclear fuel loaded in the reactor core) and (ii) Georgia Power's rights and obligations under the principal contracts relating to Plant Vogtle Units 3 and 4. See "DOE Loan Guarantee Borrowings" herein for additional information. (c) Revenue bond obligations represent loans to the traditional electric operating companies from public authorities of funds derived from sales by such authorities of revenue bonds issued to finance pollution control and solid waste disposal and wastewater facilities. In some cases, the revenue bond obligations represent obligations under installment sales agreements with respect to facilities constructed with the proceeds of revenue bonds issued by public authorities. The traditional electric operating companies are required to make payments sufficient for the authorities to meet principal and interest requirements of such bonds. Proceeds from certain issuances are restricted until qualifying expenditures are incurred. (d) Secured by substantially all of Nicor Gas' properties. (e) Secured by the underlying lease ROU asset. See Note 9 for additional information. Maturities of long-term debt for the next five years are as follows: Southern Company (a) Alabama Power Georgia Power (b) Mississippi Power Southern Power (c) Southern Company (in millions) 2023 $ 4,293 $ 301 $ 901 $ 1 $ 290 $ 400 2024 2,280 23 499 201 — — 2025 1,699 251 145 12 500 300 2026 3,726 46 445 1 964 530 2027 2,074 550 510 11 — 154 (a) See notes (b) and (c) below. (b) Amounts include principal amortization related to the FFB borrowings; however, the final maturity date is February 20, 2044. See "DOE Loan Guarantee Borrowings" herein for additional information. (c) Southern Power's 2026 maturities include $564 million of euro-denominated debt at the U.S. dollar denominated hedge settlement amount. DOE Loan Guarantee Borrowings Pursuant to the loan guarantee program established under Title XVII of the Energy Policy Act of 2005 (Title XVII Loan Guarantee Program), Georgia Power and the DOE entered into a loan guarantee agreement in 2014 and the Amended and Restated Loan Guarantee Agreement in 2019. Under the Amended and Restated Loan Guarantee Agreement, the DOE agreed to guarantee the obligations of Georgia Power under the FFB Credit Facilities. Under the FFB Credit Facilities, Georgia Power was authorized to make term loan borrowings through the FFB in an amount up to approximately $5.130 billion, provided that total aggregate borrowings under the FFB Credit Facilities could not exceed 70% of (i) Eligible Project Costs minus (ii) approximately $1.492 billion (reflecting the amounts received by Georgia Power under the Guarantee Settlement Agreement less the related customer refunds). In 2021, Georgia Power made the final borrowings under the FFB Credit Facilities and no further borrowings are permitted. During 2022, Georgia Power made principal amortization payments of $88 million under the FFB Credit Facilities. At December 31, 2022 and 2021, Georgia Power had $4.9 billion and $5.0 billion of borrowings outstanding under the FFB Credit Facilities, respectively. All borrowings under the FFB Credit Facilities are full recourse to Georgia Power, and Georgia Power is obligated to reimburse the DOE for any payments the DOE is required to make to the FFB under its guarantee. Georgia Power's reimbursement obligations to the DOE are full recourse and secured by a first priority lien on (i) Georgia Power's undivided ownership interest in Plant Vogtle Units 3 and 4 (primarily the units under construction, the related real property, and any nuclear fuel loaded in the reactor core) and (ii) Georgia Power's rights and obligations under the principal contracts relating to Plant Vogtle Units 3 and 4. There are no restrictions on Georgia Power's ability to grant liens on other property. The final maturity date for each advance under the FFB Credit Facilities is February 20, 2044. Interest is payable quarterly and principal payments began in February 2020. Each borrowing under the FFB Credit Facilities bears interest at a fixed rate equal to the applicable U.S. Treasury rate at the time of the borrowing plus a spread equal to 0.375%. Under the Amended and Restated Loan Guarantee Agreement, Georgia Power is subject to customary borrower affirmative and negative covenants and events of default. In addition, Georgia Power is subject to project-related reporting requirements and other project-specific covenants and events of default. In the event certain mandatory prepayment events occur, Georgia Power will be required to prepay the outstanding principal amount of all borrowings under the FFB Credit Facilities over a period of five years (with level principal amortization). Among other things, these mandatory prepayment events include (i) the termination of the Vogtle Services Agreement or rejection of the Vogtle Services Agreement in any Westinghouse bankruptcy if Georgia Power does not maintain access to intellectual property rights under the related intellectual property licenses; (ii) termination of the Bechtel Agreement, unless the Vogtle Owners enter into a replacement agreement; (iii) cancellation of Plant Vogtle Units 3 and 4 by the Georgia PSC or by Georgia Power; (iv) failure of the holders of 90% of the ownership interests in Plant Vogtle Units 3 and 4 to vote to continue construction following certain schedule extensions; (v) cost disallowances by the Georgia PSC that could have a material adverse effect on completion of Plant Vogtle Units 3 and 4 or Georgia Power's ability to repay the outstanding borrowings under the FFB Credit Facilities; or (vi) loss of or failure to receive necessary regulatory approvals. Under certain circumstances, insurance proceeds and any proceeds from an event of taking must be applied to immediately prepay outstanding borrowings under the FFB Credit Facilities. Georgia Power also may voluntarily prepay outstanding borrowings under the FFB Credit Facilities. Under the FFB Credit Facilities, any prepayment (whether mandatory or optional) will be made with a make-whole premium or discount, as applicable. In connection with any cancellation of Plant Vogtle Units 3 and 4, the DOE may elect to continue construction of Plant Vogtle Units 3 and 4. In such an event, the DOE will have the right to assume Georgia Power's rights and obligations under the principal agreements relating to Plant Vogtle Units 3 and 4 and to acquire all or a portion of Georgia Power's ownership interest in Plant Vogtle Units 3 and 4. See Note 2 under "Georgia Power – Nuclear Construction" for additional information. Secured Debt Each of Southern Company's subsidiaries is organized as a legal entity, separate and apart from Southern Company and its other subsidiaries. There are no agreements or other arrangements among the Southern Company system companies under which the assets of one company have been pledged or otherwise made available to satisfy obligations of Southern Company or any of its other subsidiaries. As discussed under "Long-term Debt" herein, the Registrants had secured debt outstanding at December 31, 2022 and 2021. Each Registrant's senior notes, junior subordinated notes, revenue bond obligations, bank term loans, credit facility borrowings, and notes payable are effectively subordinated to all secured debt of each respective Registrant. Equity Units In May 2022, Southern Company remarketed $862.5 million aggregate principal amount of its Series 2019A Remarketable Junior Subordinated Notes due August 1, 2024 (2019A RSNs) and $862.5 million aggregate principal amount of its Series 2019B Remarketable Junior Subordinated Notes due August 1, 2027 (2019B RSNs), pursuant to the terms of its 2019 Series A Equity Units (Equity Units). In connection with the remarketing, the interest rates on the 2019A RSNs and the 2019B RSNs were reset to 4.475% and 5.113%, respectively, payable on a semi-annual basis. On August 1, 2022, the proceeds were ultimately used to settle the purchase contracts entered into as part of the Equity Units and Southern Company issued approximately 25.2 million shares of common stock and received proceeds of $1.725 billion. At December 30, 2022 and 2021, the 2019A RSNs and the 2019B RSNs are included in long-term debt on Southern Company's consolidated balance sheets. Bank Credit Arrangements At December 31, 2022, committed credit arrangements with banks were as follows: Expires Company 2023 2024 2025 2026 Total Unused Due within (in millions) Southern Company parent $ — $ — $ — $ 2,000 $ 2,000 $ 1,998 $ — Alabama Power — 550 — 700 1,250 1,250 — Georgia Power — — — 1,750 1,750 1,726 — Mississippi Power — 150 125 — 275 275 — Southern Power (a) — — — 600 600 569 — Southern Company Gas (b) 250 — — 1,500 1,750 1,748 250 SEGCO 30 — — — 30 30 30 Southern Company $ 280 $ 700 $ 125 $ 6,550 $ 7,655 $ 7,596 $ 280 (a) Does not include Southern Power Company's two $75 million continuing letter of credit facilities for standby letters of credit, of which $9 million and $5 million, respectively, was unused at December 31, 2022. In December 2022, Southern Power amended one of the $75 million letter of credit facilities, which extended the expiration date from 2023 to 2025. The second $75 million letter of credit facility also expires in 2025. Southern Power's subsidiaries are not parties to its bank credit arrangements or letter of credit facilities. (b) Southern Company Gas, as the parent entity, guarantees the obligations of Southern Company Gas Capital, which is the borrower of $800 million of the credit arrangement expiring in 2026. Southern Company Gas' committed credit arrangement expiring in 2026 also includes $700 million for which Nicor Gas is the borrower and which is restricted for working capital needs of Nicor Gas. Pursuant to the multi-year credit arrangement expiring in 2026, the allocations between Southern Company Gas Capital and Nicor Gas may be adjusted. Nicor Gas is also the borrower under a $250 million credit arrangement expiring in 2023. See "Structural Considerations" herein for additional information. The bank credit arrangements require payment of commitment fees based on the unused portion of the commitments. Commitment fees average less than 1 / 4 of 1% for the Registrants and Nicor Gas. Subject to applicable market conditions, Southern Company and its subsidiaries expect to renew or replace their bank credit arrangements as needed, prior to expiration. In connection therewith, Southern Company and its subsidiaries may extend the maturity dates and/or increase or decrease the lending commitments thereunder. These bank credit arrangements, as well as the term loan arrangements of the Registrants, Nicor Gas, and SEGCO, contain covenants that limit debt levels and contain cross-acceleration or, in the case of Southern Power, cross-default provisions to other indebtedness (including guarantee obligations) that are restricted only to the indebtedness of the individual company. Such cross-default provisions to other indebtedness would trigger an event of default if Southern Power defaulted on indebtedness or guarantee obligations over a specified threshold. Such cross-acceleration provisions to other indebtedness would trigger an event of default if the applicable borrower defaulted on indebtedness, the payment of which was then accelerated. Southern Company's, Southern Company Gas', and Nicor Gas' credit arrangements contain covenants that limit debt levels to 70% of total capitalization, as defined in the agreements, and the other subsidiaries' bank credit arrangements contain covenants that limit debt levels to 65% of total capitalization, as defined in the agreements. For purposes of these definitions, debt excludes junior subordinated notes and, in certain arrangements, other hybrid securities. Additionally, for Southern Company and Southern Power, for purposes of these definitions, debt excludes any project debt incurred by certain subsidiaries of Southern Power to the extent such debt is non-recourse to Southern Power and capitalization excludes the capital stock or other equity attributable to such subsidiaries. At December 31, 2022, the Registrants, Nicor Gas, and SEGCO were in compliance with all such covenants. None of the bank credit arrangements contain material adverse change clauses at the time of borrowings. A portion of the unused credit with banks is allocated to provide liquidity support to the revenue bonds of the traditional electric operating companies and the commercial paper programs of the Registrants, Nicor Gas, and SEGCO. The amount of variable rate revenue bonds of the traditional electric operating companies outstanding requiring liquidity support at December 31, 2022 was approximately $1.7 billion (comprised of approximately $789 million at Alabama Power, $819 million at Georgia Power, and $69 million at Mississippi Power). In addition, at December 31, 2022, Alabama Power and Georgia Power had approximately $120 million and $288 million, respectively, of fixed rate revenue bonds outstanding that are required to be remarketed within the next 12 months. At both December 31, 2022 and 2021, Southern Power had $106 million of cash collateral posted related to PPA requirements, which is included in other deferred charges and assets on Southern Power's consolidated balance sheets. Notes Payable The Registrants, Nicor Gas, and SEGCO make short-term borrowings primarily through commercial paper programs that have the liquidity support of the committed bank credit arrangements described above under "Bank Credit Arrangements." Southern Power's subsidiaries are not parties or obligors to its commercial paper program. Southern Company Gas maintains commercial paper programs at Southern Company Gas Capital and at Nicor Gas. Nicor Gas' commercial paper program supports working capital needs at Nicor Gas as Nicor Gas is not permitted to make money pool loans to affiliates. All of Southern Company Gas' other subsidiaries benefit from Southern Company Gas Capital's commercial paper program. See "Structural Considerations" herein for additional information. In addition, Southern Company and certain of its subsidiaries have entered into various bank term loan agreements. Unless otherwise stated, the proceeds of these loans were used to repay existing indebtedness and for general corporate purposes, including working capital and, for the subsidiaries, their continuous construction programs. Commercial paper and short-term bank term loans are included in notes payable in the balance sheets. Details of short-term borrowings for the applicable Registrants were as follows: Notes Payable at December 31, 2022 Notes Payable at December 31, 2021 Amount Weighted Average Amount Weighted Average (in millions) (in millions) Southern Company Commercial paper $ 809 4.7 % $ 1,140 0.3 % Short-term bank debt 1,800 5.0 % 300 0.7 % Total $ 2,609 4.9 % $ 1,440 0.4 % Georgia Power Short-term bank debt $ 1,600 5.0 % $ — — % Southern Power Commercial paper $ 225 4.7 % $ 211 0.3 % Southern Company Gas Commercial paper: Southern Company Gas Capital $ 285 4.8 % $ 379 0.3 % Nicor Gas 283 4.6 % 530 0.3 % Short-term bank debt: Nicor Gas 200 4.9 % 300 0.7 % Total $ 768 4.7 % $ 1,209 0.4 % See "Bank Credit Arrangements" herein for information on bank term loan covenants that limit debt levels and cross-acceleration or cross-default provisions. Southern Company Common Stock Stock Issued During 2022, Southern Company issued approximately 3.6 million shares of common stock primarily through equity compensation plans and received proceeds of approximately $83 million. See "Equity Units" herein for additional information regarding Southern Company's issuance of approximately 25.2 million shares of common stock in August 2022. Shares Reserved At December 31, 2022, a total of 113 million shares were reserved for issuance pursuant to the Southern Investment Plan, employee savings plans, the Outside Directors Stock Plan, the Equity and Incentive Compensation Plan (which includes stock options and performance share units as discussed in Note 12), and an at-the-market program. Of the shares reserved, 28.9 million shares are available for awards under the Equity and Incentive Compensation Plan at December 31, 2022. Diluted Earnings Per Share For Southern Company, the only difference in computing basic and diluted earnings per share (EPS) is attributable to awards outstanding under stock-based compensation plans. Earnings per share dilution resulting from stock-based compensation plans is determined using the treasury stock method. Shares used to compute diluted EPS were as follows: Average Common Stock Shares 2022 2021 2020 (in millions) As reported shares 1,075 1,061 1,058 Effect of stock-based compensation 6 7 7 Diluted shares 1,081 1,068 1,065 In all years presented, an immaterial number of stock-based compensation awards was excluded from the diluted EPS calculation because the awards were anti-dilutive. Redeemable Preferred Stock of Subsidiaries As discussed further under "Alabama Power" herein, the preferred stock and Class A preferred stock of Alabama Power at December 31, 2021 is presented as "Redeemable Preferred Stock of Subsidiaries" on Southern Company's balance sheet in a manner consistent with temporary equity under applicable accounting standards. During 2022, Alabama Power redeemed all of its preferred stock and Class A preferred stock. Alabama Power Alabama Power has preferred stock, Class A preferred stock, preference stock, and common stock authorized, but only common stock outstanding at December 31, 2022. During 2022, Alabama Power redeemed all of its preferred stock and Class A preferred stock at the redemption prices per share provided in the table below, plus accrued and unpaid dividends to the redemption date. Preferred Stock Redeemed During 2022 Par Value/Stated Capital Per Share Shares Redemption 4.92% Preferred Stock $100 80,000 $103.23 4.72% Preferred Stock $100 50,000 $102.18 4.64% Preferred Stock $100 60,000 $103.14 4.60% Preferred Stock $100 100,000 $104.20 4.52% Preferred Stock $100 50,000 $102.93 4.20% Preferred Stock $100 135,115 $105.00 5.00% Class A Preferred Stock $25 10,000,000 $25.00 Prior to being redeemed, Alabama Power's preferred stock and Class A preferred stock, without preference between classes, ranked senior to Alabama Power's common stock with respect to payment of dividends and voluntary and involuntary dissolution. The preferred stock and Class A preferred stock of Alabama Power contained a feature that allowed the holders to elect a majority of Alabama Power's board of directors if preferred dividends were not paid for four consecutive quarters. Because such a potential redemption-triggering event was not solely within the control of Alabama Power, the preferred stock and Class A preferred stock at December 31, 2021 is presented as "Redeemable Preferred Stock" on Alabama Power's balance sheet in a manner consistent with temporary equity under applicable accounting standards. Georgia Power Georgia Power has preferred stock, Class A preferred stock, preference stock, and common stock authorized, but only common stock outstanding. Dividend Restrictions The income of Southern Company is derived primarily from equity in earnings of its subsidiaries. At December 31, 2022, consolidated retained earnings included $4.9 billion of undistributed retained earnings of the subsidiaries. The traditional electric operating companies and Southern Power can only pay dividends to Southern Company out of retained earnings or paid-in-capital. See Note 7 under "Southern Power" for information regarding the distribution requirements for certain Southern Power subsidiaries. By regulation, Nicor Gas is restricted, to the extent of its retained earnings balance, in the amount it can dividend or loan to affiliates and is not permitted to make money pool loans to affiliates. At December 31, 2022, the amount of Southern Company Gas' subsidiary retained earnings restricted for dividend payment totaled $1.5 billion. Structural Considerations Since Southern Company and Southern Company Gas are holding companies, the right of Southern Company and Southern Company Gas and, hence, the right of creditors of Southern Company or Southern Company Gas to participate in any distribution of the assets of any respective subsidiary of Southern Company or Southern Company Gas, whether upon liquidation, reorganization or otherwise, is subject to prior claims of creditors and preferred stockholders of such subsidiary. Southern Company Gas' 100%-owned subsidiary, Southern Company Gas Capital, was established to provide for certain of Southern Company Gas' ongoing financing needs through a commercial paper program, the issuance of various debt, hybrid securities, and other financing arrangements. Southern Company Gas fully and unconditionally guarantees all debt issued by Southern Company Gas Capital. Nicor Gas is not permitted by regulation to make loans to affiliates or utilize Southern Company Gas Capital for its financing needs. Southern Power Company's senior notes, bank term loan, commercial paper, and bank credit arrangement are unsecured senior indebtedness, which rank equally with all other unsecured and unsubordinated debt of Southern Power Compan y. Southern Power's subsidiaries are not issuers, borrowers, or obligors, as applicable, under any of these unsecured senior debt arrangements, which are effectively subordinated to any future secured debt of Southern Power Company and any potential claims of creditors of Southern Power's subsidiaries.

LEASES

LEASES	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
LEASES	LEASES Lessee The Registrants recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with ROU assets that will be amortized over the term of each lease. As lessee, the Registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2022 Electric generating units (*) $ 760 $ 59 $ 1,163 $ — $ — $ — Real estate/land 885 4 54 2 542 36 Communication towers 141 2 4 — — 23 Railcars 34 12 18 3 — — Other 79 4 1 21 — 1 Total $ 1,899 $ 81 $ 1,240 $ 26 $ 542 $ 60 At December 31, 2021 Electric generating units (*) $ 802 $ 104 $ 1,217 $ — $ — $ — Real estate/land 876 3 49 2 526 45 Communication towers 156 2 4 — — 24 Railcars 32 10 20 2 — — Other 103 5 1 24 — 1 Total $ 1,969 $ 124 $ 1,291 $ 28 $ 526 $ 70 (*) Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information. Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 23 years while the land leases have remaining terms of up to 44 years, including renewal periods. Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies and Nicor Gas. Communication tower leases have remaining terms of up to 10 years with options to renew that could extend the terms for an additional 20 years. Renewal options exist in many of the leases. Except as otherwise noted, the expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease as it is not considered reasonably certain that the lease will be extended. Land leases associated with renewable energy facilities at Southern Power and communication tower leases for automated meter infrastructure at Nicor Gas include renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities and the automated meter infrastructure, respectively. Contracts that Contain a Lease While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the PPA, which varies between one Short-term Leases Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Registrants generally recognize lease expense for these leases on a straight-line basis over the lease term. Residual Value Guarantees Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power and the amounts probable of being paid under those guarantees are included in the lease payments. All such amounts are immaterial at December 31, 2022 and 2021. Lease and Nonlease Components For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the Registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the right-of-use asset. Balance sheet amounts recorded for operating and finance leases are as follows: Southern Company Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2022 Operating Leases Operating lease ROU assets, net $ 1,531 $ 71 $ 1,007 $ 9 $ 489 $ 57 Operating lease obligations - current $ 197 $ 9 $ 151 $ 4 $ 28 $ 9 Operating lease obligations - non-current 1,388 67 851 5 514 51 Total operating lease obligations (*) $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance Leases Finance lease ROU assets, net $ 292 $ 5 $ 205 $ 16 $ — $ — Finance lease obligations - current $ 18 $ 2 $ 16 $ 1 $ — $ — Finance lease obligations - non-current 296 3 222 16 — — Total finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — At December 31, 2021 Operating Leases Operating lease ROU assets, net $ 1,701 $ 108 $ 1,157 $ 10 $ 479 $ 70 Operating lease obligations - current $ 250 $ 54 $ 156 $ 4 $ 28 $ 11 Operating lease obligations - non-current 1,503 66 999 6 497 59 Total operating lease obligations (*) $ 1,754 $ 121 $ 1,155 $ 10 $ 525 $ 70 Finance Leases Finance lease ROU assets, net $ 197 $ 4 $ 104 $ 17 $ — $ — Finance lease obligations - current $ 16 $ 1 $ 10 $ 1 $ — $ — Finance lease obligations - non-current 199 3 126 17 — — Total finance lease obligations $ 215 $ 4 $ 136 $ 18 $ — $ — (*) Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $652 million, $59 million, and $952 million, respectively, at December 31, 2022 and $802 million, $104 million, and $1.11 billion, respectively, at December 31, 2021. If not presented separately on the Registrants' balance sheets, amounts related to leases are presented as follows: operating lease ROU assets, net are included in "other deferred charges and assets"; operating lease obligations are included in "other current liabilities" and "other deferred credits and liabilities," as applicable; finance lease ROU assets, net are included in "plant in service"; and finance lease obligations are included in "securities due within one year" and "long-term debt," as applicable. Lease costs for 2022, 2021, and 2020, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2022 Lease cost Operating lease cost (*) $ 297 $ 59 $ 198 $ 5 $ 32 $ 15 Finance lease cost: Amortization of ROU assets 23 1 15 1 — — Interest on lease obligations 13 — 17 1 — — Total finance lease cost 36 1 32 2 — — Short-term lease costs 64 44 13 — — — Variable lease cost 125 13 105 — 5 — Sublease income (1) — — — — — Total lease cost $ 521 $ 117 $ 348 $ 7 $ 37 $ 15 2021 Lease cost Operating lease cost (*) $ 313 $ 58 $ 208 $ 2 $ 33 $ 19 Finance lease cost: Amortization of ROU assets 21 1 11 1 — — Interest on lease obligations 11 — 16 1 — — Total finance lease cost 32 1 27 2 — — Short-term lease costs 48 15 24 — — — Variable lease cost 96 4 83 — 5 — Sublease income 1 — — — — — Total lease cost $ 490 $ 78 $ 342 $ 4 $ 38 $ 19 2020 Lease cost Operating lease cost (*) $ 309 $ 55 $ 212 $ 3 $ 29 $ 19 Finance lease cost: Amortization of ROU assets 26 1 15 — — — Interest on lease obligations 11 — 16 — — — Total finance lease cost 37 1 31 — — — Short-term lease costs 39 11 26 — — — Variable lease cost 91 4 76 — 7 — Sublease income — (1) — — — — Total lease cost $ 476 $ 70 $ 345 $ 3 $ 36 $ 19 (*) Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $162 million, $48 million, and $180 million, respectively, in 2022, $165 million, $47 million, and $184 million, respectively, in 2021, and $161 million, $43 million, and $184 million, respectively, in 2020. Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs, including $45 million, $41 million, and $39 million in 2022, 2021, and 2020, respectively, from finance leases which are included in purchased power on Georgia Power's statements of income, of which $21 million, $20 million, and $20 million was included in purchased power, affiliates in 2022, 2021, and 2020, respectively. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2022 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 303 $ 58 $ 206 $ 5 $ 30 $ 14 Operating cash flows from finance leases 11 — 20 1 — — Financing cash flows from finance leases 16 1 10 1 — — ROU assets obtained under operating leases 56 10 17 9 — 3 Reassessment of ROU assets under operating leases 16 — — — 16 — ROU assets obtained under finance leases 118 2 116 — — — 2021 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 308 $ 58 $ 211 $ 2 $ 28 $ 19 Operating cash flows from finance leases 9 — 17 1 — — Financing cash flows from finance leases 17 1 9 1 — — ROU assets obtained under operating leases 64 3 9 — 72 7 ROU assets obtained under finance leases 3 — — — — — 2020 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 310 $ 55 $ 215 $ 3 $ 28 $ 18 Operating cash flows from finance leases 9 — 18 — — — Financing cash flows from finance leases 22 1 11 — — — ROU assets obtained under operating leases 227 63 32 — 51 4 ROU assets obtained under finance leases 10 2 — — — — Southern Alabama Georgia Mississippi Southern Power Southern Company Gas At December 31, 2022 Weighted-average remaining lease term in years: Operating leases 17.3 13.0 8.1 4.7 34.0 11.0 Finance leases 17.4 6.4 11.8 12.9 N/A N/A Weighted-average discount rate: Operating leases 4.51 % 4.87 % 4.52 % 3.49 % 4.86 % 3.79 % Finance leases 4.87 % 3.00 % 8.06 % 2.74 % N/A N/A At December 31, 2021 Weighted-average remaining lease term in years: Operating leases 15.9 9.1 8.7 6.1 32.8 10.5 Finance leases 18.0 8.7 8.5 13.9 N/A N/A Weighted-average discount rate: Operating leases 4.41 % 4.37 % 4.45 % 2.74 % 5.20 % 3.61 % Finance leases 4.82 % 3.09 % 10.81 % 2.74 % N/A N/A Maturities of lease liabilities are as follows: At December 31, 2022 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2023 $ 248 $ 12 $ 191 $ 4 $ 36 $ 11 2024 201 10 165 2 28 11 2025 181 9 138 2 28 11 2026 159 6 135 1 28 8 2027 143 5 135 — 29 3 Thereafter 1,497 64 440 1 1,009 31 Total 2,429 106 1,204 10 1,158 75 Less: Present value discount 844 30 202 1 616 15 Operating lease obligations $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance leases: 2023 $ 33 $ 2 $ 35 $ 2 $ — $ — 2024 22 1 27 2 — — 2025 26 1 35 2 — — 2026 26 1 36 2 — — 2027 26 — 36 2 — — Thereafter 345 — 187 10 — — Total 478 5 356 20 — — Less: Present value discount 164 — 118 3 — — Finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis. Lessor The Registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable Registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to seven years, after which the contracts renew on a month-to-month basis at the customer's option. For Mississippi Power, these arrangements also include a tolling arrangement related to an electric generating unit accounted for as a sales-type lease with a remaining term of 16 years. For Southern Power, these arrangements consist of PPAs related to electric generating units, including solar and wind facilities, accounted for as operating leases with remaining terms of up to 24 years and PPAs related to battery energy storage facilities accounted for as sales-type leases with remaining terms of up to 19 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 20 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with remaining terms of up to 11 years. Lease income for 2022, 2021, and 2020, is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) 2022 Lease income - interest income on sales-type leases $ 25 $ — $ — $ 15 $ 10 $ — Lease income - operating leases 208 77 32 2 85 36 Variable lease income 417 1 — — 448 — Total lease income $ 650 $ 78 $ 32 $ 17 $ 543 $ 36 2021 Lease income - interest income on sales-type leases $ 15 $ — $ — $ 14 $ 1 $ — Lease income - operating leases 223 82 42 2 85 35 Variable lease income 429 — — — 456 — Total lease income $ 667 $ 82 $ 42 $ 16 $ 542 $ 35 2020 Lease income - interest income on sales-type leases $ 16 $ — $ — $ 12 $ — $ — Lease income - operating leases 208 45 58 2 87 35 Variable lease income 419 — — — 449 — Total lease income $ 643 $ 45 $ 58 $ 14 $ 536 $ 35 Lease payments received under tolling arrangements and PPAs consist of either scheduled payments or variable payments based on the amount of energy produced by the underlying electric generating units. Lease income for Alabama Power and Southern Power is included in wholesale revenues. Scheduled payments to be received under outdoor lighting contracts, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses. Mississippi Power has a tolling arrangement accounted for as a sales-type lease. During 2020 and 2021, Mississippi Power completed construction of additional leased assets under the lease and, upon completion, the book values of $26 million and $39 million, respectively, were transferred from CWIP to lease receivables. Each transfer represented a non-cash investing transaction for purposes of the statements of cash flows. During 2021, Southern Power completed construction of a portion of the Garland and Tranquillity battery energy storage facilities' assets and recorded losses totaling $40 million upon commencement of the related PPAs, which Southern Power accounts for as sales-type leases. The losses were due to ITCs retained and expected to be realized by Southern Power and its partners in these projects, and no estimated residual asset value was assumed in calculating the losses. Each lease had an initial term of 20 years. Upon commencement of the leases, the book values of the related assets totaling $210 million were derecognized from CWIP and lease receivables were recorded. The transfers represented noncash investing transactions for purposes of the statement of cash flows. See Note 15 under "Southern Power" for additional information. The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows: At December 31, 2022 Southern Company Mississippi Power Southern (in millions) 2023 $ 39 $ 24 $ 15 2024 38 23 15 2025 37 22 15 2026 36 21 15 2027 35 20 15 Thereafter 364 164 200 Total undiscounted cash flows $ 549 $ 274 $ 275 Net investment in sales-type lease (*) 326 157 169 Difference between undiscounted cash flows and discounted cash flows $ 223 $ 117 $ 106 (*) For Mississippi Power, included in other current assets and other property and investments on the balance sheets. For Southern Power, included in other current assets ($15 million and $12 million at December 31, 2022 and 2021, respectively) and net investment in sales-type leases ($154 million and $161 million at December 31, 2022 and 2021, respectively) on the balance sheet. The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows: At December 31, 2022 Southern Alabama Southern Southern Company Gas (in millions) 2023 $ 145 $ 34 $ 88 $ 36 2024 114 6 90 34 2025 105 5 74 29 2026 104 3 73 29 2027 104 3 74 28 Thereafter 796 23 166 382 Total $ 1,368 $ 74 $ 565 $ 538 Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Alabama Power and Southern Power allocate revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under outdoor lighting contracts accounted for as operating leases at Georgia Power and Mississippi Power are immaterial. Southern Company Leveraged Lease At December 31, 2020, a subsidiary of Southern Holdings had four leveraged lease agreements related to energy generation, distribution, and transportation assets, including two domestic and two international projects. During 2021, one of the domestic projects was sold and the agreements for both international projects were terminated. At December 31, 2022, the one remaining leveraged lease agreement, which relates to energy generation, had an expected remaining term of nine years. Southern Company continues to receive federal income tax deductions for depreciation and amortization, as well as interest on long-term debt related to this investment. Southern Company wrote off the related investment balance in 2020, as discussed below. During the second quarter 2020, following an evaluation of the recoverability of the lease receivable and the expected residual value of the generation assets at the end of the lease, Southern Company management concluded it was no longer probable that any of the associated rental payments scheduled after 2032 would be received, because it was no longer probable the generation assets would be successfully remarketed and continue to operate after that date. Revising the estimated cash flows to be received under the leveraged lease to reflect this conclusion resulted in a full impairment of the lease investment and a pre-tax charge to earnings of $154 million ($74 million after tax). The following table provides a summary of the components of income related to leveraged lease investments. Income was impacted in 2021 and 2020 by the impairment charges discussed below and in Note 15 under "Southern Company." Income in 2021 does not include the impacts of the sale and terminations of leveraged lease projects discussed in Note 15 under "Southern Company." 2021 2020 (in millions) Pretax leveraged lease income (loss) $ 17 $ (180) Income tax benefit (expense) (5) 98 Net leveraged lease income (loss) $ 12 $ (82) On June 30, 2022, the Southern Holdings subsidiary operating the generating plant for the lessee provided notice to the lessee to terminate the related operating and maintenance agreement effective June 30, 2023. The parties to the lease agreement are currently negotiating a potential restructuring, which could result in rescission of the termination notice. The ultimate outcome of this matter cannot be determined at this time but is not expected to have a material impact on Southern Company's financial statements. The lessee failed to make the semi-annual lease payment due December 15, 2022. As a result, the Southern Holdings subsidiary was unable to make its corresponding payment to the holders of the underlying non-recourse debt related to the generation assets. The parties to the lease have entered into a forbearance agreement which suspends the related contractual rights of the parties while they continue restructuring negotiations. As the remaining amount of Southern Company's lease investment was charged against earnings in the second quarter 2020, termination would not be expected to result in additional charges. Southern Company will continue to monitor the operational performance of the underlying assets and evaluate the ability of the lessee to continue to make the required lease payments and meet its obligations associated with a future closure or retirement of the generation assets and associated properties, including the dry ash landfill.
LEASES	LEASES Lessee The Registrants recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with ROU assets that will be amortized over the term of each lease. As lessee, the Registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2022 Electric generating units (*) $ 760 $ 59 $ 1,163 $ — $ — $ — Real estate/land 885 4 54 2 542 36 Communication towers 141 2 4 — — 23 Railcars 34 12 18 3 — — Other 79 4 1 21 — 1 Total $ 1,899 $ 81 $ 1,240 $ 26 $ 542 $ 60 At December 31, 2021 Electric generating units (*) $ 802 $ 104 $ 1,217 $ — $ — $ — Real estate/land 876 3 49 2 526 45 Communication towers 156 2 4 — — 24 Railcars 32 10 20 2 — — Other 103 5 1 24 — 1 Total $ 1,969 $ 124 $ 1,291 $ 28 $ 526 $ 70 (*) Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information. Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 23 years while the land leases have remaining terms of up to 44 years, including renewal periods. Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies and Nicor Gas. Communication tower leases have remaining terms of up to 10 years with options to renew that could extend the terms for an additional 20 years. Renewal options exist in many of the leases. Except as otherwise noted, the expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease as it is not considered reasonably certain that the lease will be extended. Land leases associated with renewable energy facilities at Southern Power and communication tower leases for automated meter infrastructure at Nicor Gas include renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities and the automated meter infrastructure, respectively. Contracts that Contain a Lease While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the PPA, which varies between one Short-term Leases Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Registrants generally recognize lease expense for these leases on a straight-line basis over the lease term. Residual Value Guarantees Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power and the amounts probable of being paid under those guarantees are included in the lease payments. All such amounts are immaterial at December 31, 2022 and 2021. Lease and Nonlease Components For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the Registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the right-of-use asset. Balance sheet amounts recorded for operating and finance leases are as follows: Southern Company Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2022 Operating Leases Operating lease ROU assets, net $ 1,531 $ 71 $ 1,007 $ 9 $ 489 $ 57 Operating lease obligations - current $ 197 $ 9 $ 151 $ 4 $ 28 $ 9 Operating lease obligations - non-current 1,388 67 851 5 514 51 Total operating lease obligations (*) $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance Leases Finance lease ROU assets, net $ 292 $ 5 $ 205 $ 16 $ — $ — Finance lease obligations - current $ 18 $ 2 $ 16 $ 1 $ — $ — Finance lease obligations - non-current 296 3 222 16 — — Total finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — At December 31, 2021 Operating Leases Operating lease ROU assets, net $ 1,701 $ 108 $ 1,157 $ 10 $ 479 $ 70 Operating lease obligations - current $ 250 $ 54 $ 156 $ 4 $ 28 $ 11 Operating lease obligations - non-current 1,503 66 999 6 497 59 Total operating lease obligations (*) $ 1,754 $ 121 $ 1,155 $ 10 $ 525 $ 70 Finance Leases Finance lease ROU assets, net $ 197 $ 4 $ 104 $ 17 $ — $ — Finance lease obligations - current $ 16 $ 1 $ 10 $ 1 $ — $ — Finance lease obligations - non-current 199 3 126 17 — — Total finance lease obligations $ 215 $ 4 $ 136 $ 18 $ — $ — (*) Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $652 million, $59 million, and $952 million, respectively, at December 31, 2022 and $802 million, $104 million, and $1.11 billion, respectively, at December 31, 2021. If not presented separately on the Registrants' balance sheets, amounts related to leases are presented as follows: operating lease ROU assets, net are included in "other deferred charges and assets"; operating lease obligations are included in "other current liabilities" and "other deferred credits and liabilities," as applicable; finance lease ROU assets, net are included in "plant in service"; and finance lease obligations are included in "securities due within one year" and "long-term debt," as applicable. Lease costs for 2022, 2021, and 2020, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2022 Lease cost Operating lease cost (*) $ 297 $ 59 $ 198 $ 5 $ 32 $ 15 Finance lease cost: Amortization of ROU assets 23 1 15 1 — — Interest on lease obligations 13 — 17 1 — — Total finance lease cost 36 1 32 2 — — Short-term lease costs 64 44 13 — — — Variable lease cost 125 13 105 — 5 — Sublease income (1) — — — — — Total lease cost $ 521 $ 117 $ 348 $ 7 $ 37 $ 15 2021 Lease cost Operating lease cost (*) $ 313 $ 58 $ 208 $ 2 $ 33 $ 19 Finance lease cost: Amortization of ROU assets 21 1 11 1 — — Interest on lease obligations 11 — 16 1 — — Total finance lease cost 32 1 27 2 — — Short-term lease costs 48 15 24 — — — Variable lease cost 96 4 83 — 5 — Sublease income 1 — — — — — Total lease cost $ 490 $ 78 $ 342 $ 4 $ 38 $ 19 2020 Lease cost Operating lease cost (*) $ 309 $ 55 $ 212 $ 3 $ 29 $ 19 Finance lease cost: Amortization of ROU assets 26 1 15 — — — Interest on lease obligations 11 — 16 — — — Total finance lease cost 37 1 31 — — — Short-term lease costs 39 11 26 — — — Variable lease cost 91 4 76 — 7 — Sublease income — (1) — — — — Total lease cost $ 476 $ 70 $ 345 $ 3 $ 36 $ 19 (*) Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $162 million, $48 million, and $180 million, respectively, in 2022, $165 million, $47 million, and $184 million, respectively, in 2021, and $161 million, $43 million, and $184 million, respectively, in 2020. Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs, including $45 million, $41 million, and $39 million in 2022, 2021, and 2020, respectively, from finance leases which are included in purchased power on Georgia Power's statements of income, of which $21 million, $20 million, and $20 million was included in purchased power, affiliates in 2022, 2021, and 2020, respectively. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2022 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 303 $ 58 $ 206 $ 5 $ 30 $ 14 Operating cash flows from finance leases 11 — 20 1 — — Financing cash flows from finance leases 16 1 10 1 — — ROU assets obtained under operating leases 56 10 17 9 — 3 Reassessment of ROU assets under operating leases 16 — — — 16 — ROU assets obtained under finance leases 118 2 116 — — — 2021 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 308 $ 58 $ 211 $ 2 $ 28 $ 19 Operating cash flows from finance leases 9 — 17 1 — — Financing cash flows from finance leases 17 1 9 1 — — ROU assets obtained under operating leases 64 3 9 — 72 7 ROU assets obtained under finance leases 3 — — — — — 2020 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 310 $ 55 $ 215 $ 3 $ 28 $ 18 Operating cash flows from finance leases 9 — 18 — — — Financing cash flows from finance leases 22 1 11 — — — ROU assets obtained under operating leases 227 63 32 — 51 4 ROU assets obtained under finance leases 10 2 — — — — Southern Alabama Georgia Mississippi Southern Power Southern Company Gas At December 31, 2022 Weighted-average remaining lease term in years: Operating leases 17.3 13.0 8.1 4.7 34.0 11.0 Finance leases 17.4 6.4 11.8 12.9 N/A N/A Weighted-average discount rate: Operating leases 4.51 % 4.87 % 4.52 % 3.49 % 4.86 % 3.79 % Finance leases 4.87 % 3.00 % 8.06 % 2.74 % N/A N/A At December 31, 2021 Weighted-average remaining lease term in years: Operating leases 15.9 9.1 8.7 6.1 32.8 10.5 Finance leases 18.0 8.7 8.5 13.9 N/A N/A Weighted-average discount rate: Operating leases 4.41 % 4.37 % 4.45 % 2.74 % 5.20 % 3.61 % Finance leases 4.82 % 3.09 % 10.81 % 2.74 % N/A N/A Maturities of lease liabilities are as follows: At December 31, 2022 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2023 $ 248 $ 12 $ 191 $ 4 $ 36 $ 11 2024 201 10 165 2 28 11 2025 181 9 138 2 28 11 2026 159 6 135 1 28 8 2027 143 5 135 — 29 3 Thereafter 1,497 64 440 1 1,009 31 Total 2,429 106 1,204 10 1,158 75 Less: Present value discount 844 30 202 1 616 15 Operating lease obligations $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance leases: 2023 $ 33 $ 2 $ 35 $ 2 $ — $ — 2024 22 1 27 2 — — 2025 26 1 35 2 — — 2026 26 1 36 2 — — 2027 26 — 36 2 — — Thereafter 345 — 187 10 — — Total 478 5 356 20 — — Less: Present value discount 164 — 118 3 — — Finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis. Lessor The Registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable Registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to seven years, after which the contracts renew on a month-to-month basis at the customer's option. For Mississippi Power, these arrangements also include a tolling arrangement related to an electric generating unit accounted for as a sales-type lease with a remaining term of 16 years. For Southern Power, these arrangements consist of PPAs related to electric generating units, including solar and wind facilities, accounted for as operating leases with remaining terms of up to 24 years and PPAs related to battery energy storage facilities accounted for as sales-type leases with remaining terms of up to 19 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 20 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with remaining terms of up to 11 years. Lease income for 2022, 2021, and 2020, is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) 2022 Lease income - interest income on sales-type leases $ 25 $ — $ — $ 15 $ 10 $ — Lease income - operating leases 208 77 32 2 85 36 Variable lease income 417 1 — — 448 — Total lease income $ 650 $ 78 $ 32 $ 17 $ 543 $ 36 2021 Lease income - interest income on sales-type leases $ 15 $ — $ — $ 14 $ 1 $ — Lease income - operating leases 223 82 42 2 85 35 Variable lease income 429 — — — 456 — Total lease income $ 667 $ 82 $ 42 $ 16 $ 542 $ 35 2020 Lease income - interest income on sales-type leases $ 16 $ — $ — $ 12 $ — $ — Lease income - operating leases 208 45 58 2 87 35 Variable lease income 419 — — — 449 — Total lease income $ 643 $ 45 $ 58 $ 14 $ 536 $ 35 Lease payments received under tolling arrangements and PPAs consist of either scheduled payments or variable payments based on the amount of energy produced by the underlying electric generating units. Lease income for Alabama Power and Southern Power is included in wholesale revenues. Scheduled payments to be received under outdoor lighting contracts, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses. Mississippi Power has a tolling arrangement accounted for as a sales-type lease. During 2020 and 2021, Mississippi Power completed construction of additional leased assets under the lease and, upon completion, the book values of $26 million and $39 million, respectively, were transferred from CWIP to lease receivables. Each transfer represented a non-cash investing transaction for purposes of the statements of cash flows. During 2021, Southern Power completed construction of a portion of the Garland and Tranquillity battery energy storage facilities' assets and recorded losses totaling $40 million upon commencement of the related PPAs, which Southern Power accounts for as sales-type leases. The losses were due to ITCs retained and expected to be realized by Southern Power and its partners in these projects, and no estimated residual asset value was assumed in calculating the losses. Each lease had an initial term of 20 years. Upon commencement of the leases, the book values of the related assets totaling $210 million were derecognized from CWIP and lease receivables were recorded. The transfers represented noncash investing transactions for purposes of the statement of cash flows. See Note 15 under "Southern Power" for additional information. The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows: At December 31, 2022 Southern Company Mississippi Power Southern (in millions) 2023 $ 39 $ 24 $ 15 2024 38 23 15 2025 37 22 15 2026 36 21 15 2027 35 20 15 Thereafter 364 164 200 Total undiscounted cash flows $ 549 $ 274 $ 275 Net investment in sales-type lease (*) 326 157 169 Difference between undiscounted cash flows and discounted cash flows $ 223 $ 117 $ 106 (*) For Mississippi Power, included in other current assets and other property and investments on the balance sheets. For Southern Power, included in other current assets ($15 million and $12 million at December 31, 2022 and 2021, respectively) and net investment in sales-type leases ($154 million and $161 million at December 31, 2022 and 2021, respectively) on the balance sheet. The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows: At December 31, 2022 Southern Alabama Southern Southern Company Gas (in millions) 2023 $ 145 $ 34 $ 88 $ 36 2024 114 6 90 34 2025 105 5 74 29 2026 104 3 73 29 2027 104 3 74 28 Thereafter 796 23 166 382 Total $ 1,368 $ 74 $ 565 $ 538 Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Alabama Power and Southern Power allocate revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under outdoor lighting contracts accounted for as operating leases at Georgia Power and Mississippi Power are immaterial. Southern Company Leveraged Lease At December 31, 2020, a subsidiary of Southern Holdings had four leveraged lease agreements related to energy generation, distribution, and transportation assets, including two domestic and two international projects. During 2021, one of the domestic projects was sold and the agreements for both international projects were terminated. At December 31, 2022, the one remaining leveraged lease agreement, which relates to energy generation, had an expected remaining term of nine years. Southern Company continues to receive federal income tax deductions for depreciation and amortization, as well as interest on long-term debt related to this investment. Southern Company wrote off the related investment balance in 2020, as discussed below. During the second quarter 2020, following an evaluation of the recoverability of the lease receivable and the expected residual value of the generation assets at the end of the lease, Southern Company management concluded it was no longer probable that any of the associated rental payments scheduled after 2032 would be received, because it was no longer probable the generation assets would be successfully remarketed and continue to operate after that date. Revising the estimated cash flows to be received under the leveraged lease to reflect this conclusion resulted in a full impairment of the lease investment and a pre-tax charge to earnings of $154 million ($74 million after tax). The following table provides a summary of the components of income related to leveraged lease investments. Income was impacted in 2021 and 2020 by the impairment charges discussed below and in Note 15 under "Southern Company." Income in 2021 does not include the impacts of the sale and terminations of leveraged lease projects discussed in Note 15 under "Southern Company." 2021 2020 (in millions) Pretax leveraged lease income (loss) $ 17 $ (180) Income tax benefit (expense) (5) 98 Net leveraged lease income (loss) $ 12 $ (82) On June 30, 2022, the Southern Holdings subsidiary operating the generating plant for the lessee provided notice to the lessee to terminate the related operating and maintenance agreement effective June 30, 2023. The parties to the lease agreement are currently negotiating a potential restructuring, which could result in rescission of the termination notice. The ultimate outcome of this matter cannot be determined at this time but is not expected to have a material impact on Southern Company's financial statements. The lessee failed to make the semi-annual lease payment due December 15, 2022. As a result, the Southern Holdings subsidiary was unable to make its corresponding payment to the holders of the underlying non-recourse debt related to the generation assets. The parties to the lease have entered into a forbearance agreement which suspends the related contractual rights of the parties while they continue restructuring negotiations. As the remaining amount of Southern Company's lease investment was charged against earnings in the second quarter 2020, termination would not be expected to result in additional charges. Southern Company will continue to monitor the operational performance of the underlying assets and evaluate the ability of the lessee to continue to make the required lease payments and meet its obligations associated with a future closure or retirement of the generation assets and associated properties, including the dry ash landfill.
LEASES	LEASES Lessee The Registrants recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with ROU assets that will be amortized over the term of each lease. As lessee, the Registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2022 Electric generating units (*) $ 760 $ 59 $ 1,163 $ — $ — $ — Real estate/land 885 4 54 2 542 36 Communication towers 141 2 4 — — 23 Railcars 34 12 18 3 — — Other 79 4 1 21 — 1 Total $ 1,899 $ 81 $ 1,240 $ 26 $ 542 $ 60 At December 31, 2021 Electric generating units (*) $ 802 $ 104 $ 1,217 $ — $ — $ — Real estate/land 876 3 49 2 526 45 Communication towers 156 2 4 — — 24 Railcars 32 10 20 2 — — Other 103 5 1 24 — 1 Total $ 1,969 $ 124 $ 1,291 $ 28 $ 526 $ 70 (*) Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information. Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 23 years while the land leases have remaining terms of up to 44 years, including renewal periods. Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies and Nicor Gas. Communication tower leases have remaining terms of up to 10 years with options to renew that could extend the terms for an additional 20 years. Renewal options exist in many of the leases. Except as otherwise noted, the expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease as it is not considered reasonably certain that the lease will be extended. Land leases associated with renewable energy facilities at Southern Power and communication tower leases for automated meter infrastructure at Nicor Gas include renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities and the automated meter infrastructure, respectively. Contracts that Contain a Lease While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the PPA, which varies between one Short-term Leases Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Registrants generally recognize lease expense for these leases on a straight-line basis over the lease term. Residual Value Guarantees Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power and the amounts probable of being paid under those guarantees are included in the lease payments. All such amounts are immaterial at December 31, 2022 and 2021. Lease and Nonlease Components For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the Registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the right-of-use asset. Balance sheet amounts recorded for operating and finance leases are as follows: Southern Company Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2022 Operating Leases Operating lease ROU assets, net $ 1,531 $ 71 $ 1,007 $ 9 $ 489 $ 57 Operating lease obligations - current $ 197 $ 9 $ 151 $ 4 $ 28 $ 9 Operating lease obligations - non-current 1,388 67 851 5 514 51 Total operating lease obligations (*) $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance Leases Finance lease ROU assets, net $ 292 $ 5 $ 205 $ 16 $ — $ — Finance lease obligations - current $ 18 $ 2 $ 16 $ 1 $ — $ — Finance lease obligations - non-current 296 3 222 16 — — Total finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — At December 31, 2021 Operating Leases Operating lease ROU assets, net $ 1,701 $ 108 $ 1,157 $ 10 $ 479 $ 70 Operating lease obligations - current $ 250 $ 54 $ 156 $ 4 $ 28 $ 11 Operating lease obligations - non-current 1,503 66 999 6 497 59 Total operating lease obligations (*) $ 1,754 $ 121 $ 1,155 $ 10 $ 525 $ 70 Finance Leases Finance lease ROU assets, net $ 197 $ 4 $ 104 $ 17 $ — $ — Finance lease obligations - current $ 16 $ 1 $ 10 $ 1 $ — $ — Finance lease obligations - non-current 199 3 126 17 — — Total finance lease obligations $ 215 $ 4 $ 136 $ 18 $ — $ — (*) Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $652 million, $59 million, and $952 million, respectively, at December 31, 2022 and $802 million, $104 million, and $1.11 billion, respectively, at December 31, 2021. If not presented separately on the Registrants' balance sheets, amounts related to leases are presented as follows: operating lease ROU assets, net are included in "other deferred charges and assets"; operating lease obligations are included in "other current liabilities" and "other deferred credits and liabilities," as applicable; finance lease ROU assets, net are included in "plant in service"; and finance lease obligations are included in "securities due within one year" and "long-term debt," as applicable. Lease costs for 2022, 2021, and 2020, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2022 Lease cost Operating lease cost (*) $ 297 $ 59 $ 198 $ 5 $ 32 $ 15 Finance lease cost: Amortization of ROU assets 23 1 15 1 — — Interest on lease obligations 13 — 17 1 — — Total finance lease cost 36 1 32 2 — — Short-term lease costs 64 44 13 — — — Variable lease cost 125 13 105 — 5 — Sublease income (1) — — — — — Total lease cost $ 521 $ 117 $ 348 $ 7 $ 37 $ 15 2021 Lease cost Operating lease cost (*) $ 313 $ 58 $ 208 $ 2 $ 33 $ 19 Finance lease cost: Amortization of ROU assets 21 1 11 1 — — Interest on lease obligations 11 — 16 1 — — Total finance lease cost 32 1 27 2 — — Short-term lease costs 48 15 24 — — — Variable lease cost 96 4 83 — 5 — Sublease income 1 — — — — — Total lease cost $ 490 $ 78 $ 342 $ 4 $ 38 $ 19 2020 Lease cost Operating lease cost (*) $ 309 $ 55 $ 212 $ 3 $ 29 $ 19 Finance lease cost: Amortization of ROU assets 26 1 15 — — — Interest on lease obligations 11 — 16 — — — Total finance lease cost 37 1 31 — — — Short-term lease costs 39 11 26 — — — Variable lease cost 91 4 76 — 7 — Sublease income — (1) — — — — Total lease cost $ 476 $ 70 $ 345 $ 3 $ 36 $ 19 (*) Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $162 million, $48 million, and $180 million, respectively, in 2022, $165 million, $47 million, and $184 million, respectively, in 2021, and $161 million, $43 million, and $184 million, respectively, in 2020. Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs, including $45 million, $41 million, and $39 million in 2022, 2021, and 2020, respectively, from finance leases which are included in purchased power on Georgia Power's statements of income, of which $21 million, $20 million, and $20 million was included in purchased power, affiliates in 2022, 2021, and 2020, respectively. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2022 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 303 $ 58 $ 206 $ 5 $ 30 $ 14 Operating cash flows from finance leases 11 — 20 1 — — Financing cash flows from finance leases 16 1 10 1 — — ROU assets obtained under operating leases 56 10 17 9 — 3 Reassessment of ROU assets under operating leases 16 — — — 16 — ROU assets obtained under finance leases 118 2 116 — — — 2021 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 308 $ 58 $ 211 $ 2 $ 28 $ 19 Operating cash flows from finance leases 9 — 17 1 — — Financing cash flows from finance leases 17 1 9 1 — — ROU assets obtained under operating leases 64 3 9 — 72 7 ROU assets obtained under finance leases 3 — — — — — 2020 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 310 $ 55 $ 215 $ 3 $ 28 $ 18 Operating cash flows from finance leases 9 — 18 — — — Financing cash flows from finance leases 22 1 11 — — — ROU assets obtained under operating leases 227 63 32 — 51 4 ROU assets obtained under finance leases 10 2 — — — — Southern Alabama Georgia Mississippi Southern Power Southern Company Gas At December 31, 2022 Weighted-average remaining lease term in years: Operating leases 17.3 13.0 8.1 4.7 34.0 11.0 Finance leases 17.4 6.4 11.8 12.9 N/A N/A Weighted-average discount rate: Operating leases 4.51 % 4.87 % 4.52 % 3.49 % 4.86 % 3.79 % Finance leases 4.87 % 3.00 % 8.06 % 2.74 % N/A N/A At December 31, 2021 Weighted-average remaining lease term in years: Operating leases 15.9 9.1 8.7 6.1 32.8 10.5 Finance leases 18.0 8.7 8.5 13.9 N/A N/A Weighted-average discount rate: Operating leases 4.41 % 4.37 % 4.45 % 2.74 % 5.20 % 3.61 % Finance leases 4.82 % 3.09 % 10.81 % 2.74 % N/A N/A Maturities of lease liabilities are as follows: At December 31, 2022 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2023 $ 248 $ 12 $ 191 $ 4 $ 36 $ 11 2024 201 10 165 2 28 11 2025 181 9 138 2 28 11 2026 159 6 135 1 28 8 2027 143 5 135 — 29 3 Thereafter 1,497 64 440 1 1,009 31 Total 2,429 106 1,204 10 1,158 75 Less: Present value discount 844 30 202 1 616 15 Operating lease obligations $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance leases: 2023 $ 33 $ 2 $ 35 $ 2 $ — $ — 2024 22 1 27 2 — — 2025 26 1 35 2 — — 2026 26 1 36 2 — — 2027 26 — 36 2 — — Thereafter 345 — 187 10 — — Total 478 5 356 20 — — Less: Present value discount 164 — 118 3 — — Finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis. Lessor The Registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable Registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to seven years, after which the contracts renew on a month-to-month basis at the customer's option. For Mississippi Power, these arrangements also include a tolling arrangement related to an electric generating unit accounted for as a sales-type lease with a remaining term of 16 years. For Southern Power, these arrangements consist of PPAs related to electric generating units, including solar and wind facilities, accounted for as operating leases with remaining terms of up to 24 years and PPAs related to battery energy storage facilities accounted for as sales-type leases with remaining terms of up to 19 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 20 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with remaining terms of up to 11 years. Lease income for 2022, 2021, and 2020, is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) 2022 Lease income - interest income on sales-type leases $ 25 $ — $ — $ 15 $ 10 $ — Lease income - operating leases 208 77 32 2 85 36 Variable lease income 417 1 — — 448 — Total lease income $ 650 $ 78 $ 32 $ 17 $ 543 $ 36 2021 Lease income - interest income on sales-type leases $ 15 $ — $ — $ 14 $ 1 $ — Lease income - operating leases 223 82 42 2 85 35 Variable lease income 429 — — — 456 — Total lease income $ 667 $ 82 $ 42 $ 16 $ 542 $ 35 2020 Lease income - interest income on sales-type leases $ 16 $ — $ — $ 12 $ — $ — Lease income - operating leases 208 45 58 2 87 35 Variable lease income 419 — — — 449 — Total lease income $ 643 $ 45 $ 58 $ 14 $ 536 $ 35 Lease payments received under tolling arrangements and PPAs consist of either scheduled payments or variable payments based on the amount of energy produced by the underlying electric generating units. Lease income for Alabama Power and Southern Power is included in wholesale revenues. Scheduled payments to be received under outdoor lighting contracts, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses. Mississippi Power has a tolling arrangement accounted for as a sales-type lease. During 2020 and 2021, Mississippi Power completed construction of additional leased assets under the lease and, upon completion, the book values of $26 million and $39 million, respectively, were transferred from CWIP to lease receivables. Each transfer represented a non-cash investing transaction for purposes of the statements of cash flows. During 2021, Southern Power completed construction of a portion of the Garland and Tranquillity battery energy storage facilities' assets and recorded losses totaling $40 million upon commencement of the related PPAs, which Southern Power accounts for as sales-type leases. The losses were due to ITCs retained and expected to be realized by Southern Power and its partners in these projects, and no estimated residual asset value was assumed in calculating the losses. Each lease had an initial term of 20 years. Upon commencement of the leases, the book values of the related assets totaling $210 million were derecognized from CWIP and lease receivables were recorded. The transfers represented noncash investing transactions for purposes of the statement of cash flows. See Note 15 under "Southern Power" for additional information. The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows: At December 31, 2022 Southern Company Mississippi Power Southern (in millions) 2023 $ 39 $ 24 $ 15 2024 38 23 15 2025 37 22 15 2026 36 21 15 2027 35 20 15 Thereafter 364 164 200 Total undiscounted cash flows $ 549 $ 274 $ 275 Net investment in sales-type lease (*) 326 157 169 Difference between undiscounted cash flows and discounted cash flows $ 223 $ 117 $ 106 (*) For Mississippi Power, included in other current assets and other property and investments on the balance sheets. For Southern Power, included in other current assets ($15 million and $12 million at December 31, 2022 and 2021, respectively) and net investment in sales-type leases ($154 million and $161 million at December 31, 2022 and 2021, respectively) on the balance sheet. The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows: At December 31, 2022 Southern Alabama Southern Southern Company Gas (in millions) 2023 $ 145 $ 34 $ 88 $ 36 2024 114 6 90 34 2025 105 5 74 29 2026 104 3 73 29 2027 104 3 74 28 Thereafter 796 23 166 382 Total $ 1,368 $ 74 $ 565 $ 538 Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Alabama Power and Southern Power allocate revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under outdoor lighting contracts accounted for as operating leases at Georgia Power and Mississippi Power are immaterial. Southern Company Leveraged Lease At December 31, 2020, a subsidiary of Southern Holdings had four leveraged lease agreements related to energy generation, distribution, and transportation assets, including two domestic and two international projects. During 2021, one of the domestic projects was sold and the agreements for both international projects were terminated. At December 31, 2022, the one remaining leveraged lease agreement, which relates to energy generation, had an expected remaining term of nine years. Southern Company continues to receive federal income tax deductions for depreciation and amortization, as well as interest on long-term debt related to this investment. Southern Company wrote off the related investment balance in 2020, as discussed below. During the second quarter 2020, following an evaluation of the recoverability of the lease receivable and the expected residual value of the generation assets at the end of the lease, Southern Company management concluded it was no longer probable that any of the associated rental payments scheduled after 2032 would be received, because it was no longer probable the generation assets would be successfully remarketed and continue to operate after that date. Revising the estimated cash flows to be received under the leveraged lease to reflect this conclusion resulted in a full impairment of the lease investment and a pre-tax charge to earnings of $154 million ($74 million after tax). The following table provides a summary of the components of income related to leveraged lease investments. Income was impacted in 2021 and 2020 by the impairment charges discussed below and in Note 15 under "Southern Company." Income in 2021 does not include the impacts of the sale and terminations of leveraged lease projects discussed in Note 15 under "Southern Company." 2021 2020 (in millions) Pretax leveraged lease income (loss) $ 17 $ (180) Income tax benefit (expense) (5) 98 Net leveraged lease income (loss) $ 12 $ (82) On June 30, 2022, the Southern Holdings subsidiary operating the generating plant for the lessee provided notice to the lessee to terminate the related operating and maintenance agreement effective June 30, 2023. The parties to the lease agreement are currently negotiating a potential restructuring, which could result in rescission of the termination notice. The ultimate outcome of this matter cannot be determined at this time but is not expected to have a material impact on Southern Company's financial statements. The lessee failed to make the semi-annual lease payment due December 15, 2022. As a result, the Southern Holdings subsidiary was unable to make its corresponding payment to the holders of the underlying non-recourse debt related to the generation assets. The parties to the lease have entered into a forbearance agreement which suspends the related contractual rights of the parties while they continue restructuring negotiations. As the remaining amount of Southern Company's lease investment was charged against earnings in the second quarter 2020, termination would not be expected to result in additional charges. Southern Company will continue to monitor the operational performance of the underlying assets and evaluate the ability of the lessee to continue to make the required lease payments and meet its obligations associated with a future closure or retirement of the generation assets and associated properties, including the dry ash landfill.
LEASES	LEASES Lessee The Registrants recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with ROU assets that will be amortized over the term of each lease. As lessee, the Registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2022 Electric generating units (*) $ 760 $ 59 $ 1,163 $ — $ — $ — Real estate/land 885 4 54 2 542 36 Communication towers 141 2 4 — — 23 Railcars 34 12 18 3 — — Other 79 4 1 21 — 1 Total $ 1,899 $ 81 $ 1,240 $ 26 $ 542 $ 60 At December 31, 2021 Electric generating units (*) $ 802 $ 104 $ 1,217 $ — $ — $ — Real estate/land 876 3 49 2 526 45 Communication towers 156 2 4 — — 24 Railcars 32 10 20 2 — — Other 103 5 1 24 — 1 Total $ 1,969 $ 124 $ 1,291 $ 28 $ 526 $ 70 (*) Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information. Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 23 years while the land leases have remaining terms of up to 44 years, including renewal periods. Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies and Nicor Gas. Communication tower leases have remaining terms of up to 10 years with options to renew that could extend the terms for an additional 20 years. Renewal options exist in many of the leases. Except as otherwise noted, the expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease as it is not considered reasonably certain that the lease will be extended. Land leases associated with renewable energy facilities at Southern Power and communication tower leases for automated meter infrastructure at Nicor Gas include renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities and the automated meter infrastructure, respectively. Contracts that Contain a Lease While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the PPA, which varies between one Short-term Leases Leases with an initial term of 12 months or less are not recorded on the balance sheet; the Registrants generally recognize lease expense for these leases on a straight-line basis over the lease term. Residual Value Guarantees Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power and the amounts probable of being paid under those guarantees are included in the lease payments. All such amounts are immaterial at December 31, 2022 and 2021. Lease and Nonlease Components For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the Registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the right-of-use asset. Balance sheet amounts recorded for operating and finance leases are as follows: Southern Company Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2022 Operating Leases Operating lease ROU assets, net $ 1,531 $ 71 $ 1,007 $ 9 $ 489 $ 57 Operating lease obligations - current $ 197 $ 9 $ 151 $ 4 $ 28 $ 9 Operating lease obligations - non-current 1,388 67 851 5 514 51 Total operating lease obligations (*) $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance Leases Finance lease ROU assets, net $ 292 $ 5 $ 205 $ 16 $ — $ — Finance lease obligations - current $ 18 $ 2 $ 16 $ 1 $ — $ — Finance lease obligations - non-current 296 3 222 16 — — Total finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — At December 31, 2021 Operating Leases Operating lease ROU assets, net $ 1,701 $ 108 $ 1,157 $ 10 $ 479 $ 70 Operating lease obligations - current $ 250 $ 54 $ 156 $ 4 $ 28 $ 11 Operating lease obligations - non-current 1,503 66 999 6 497 59 Total operating lease obligations (*) $ 1,754 $ 121 $ 1,155 $ 10 $ 525 $ 70 Finance Leases Finance lease ROU assets, net $ 197 $ 4 $ 104 $ 17 $ — $ — Finance lease obligations - current $ 16 $ 1 $ 10 $ 1 $ — $ — Finance lease obligations - non-current 199 3 126 17 — — Total finance lease obligations $ 215 $ 4 $ 136 $ 18 $ — $ — (*) Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $652 million, $59 million, and $952 million, respectively, at December 31, 2022 and $802 million, $104 million, and $1.11 billion, respectively, at December 31, 2021. If not presented separately on the Registrants' balance sheets, amounts related to leases are presented as follows: operating lease ROU assets, net are included in "other deferred charges and assets"; operating lease obligations are included in "other current liabilities" and "other deferred credits and liabilities," as applicable; finance lease ROU assets, net are included in "plant in service"; and finance lease obligations are included in "securities due within one year" and "long-term debt," as applicable. Lease costs for 2022, 2021, and 2020, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2022 Lease cost Operating lease cost (*) $ 297 $ 59 $ 198 $ 5 $ 32 $ 15 Finance lease cost: Amortization of ROU assets 23 1 15 1 — — Interest on lease obligations 13 — 17 1 — — Total finance lease cost 36 1 32 2 — — Short-term lease costs 64 44 13 — — — Variable lease cost 125 13 105 — 5 — Sublease income (1) — — — — — Total lease cost $ 521 $ 117 $ 348 $ 7 $ 37 $ 15 2021 Lease cost Operating lease cost (*) $ 313 $ 58 $ 208 $ 2 $ 33 $ 19 Finance lease cost: Amortization of ROU assets 21 1 11 1 — — Interest on lease obligations 11 — 16 1 — — Total finance lease cost 32 1 27 2 — — Short-term lease costs 48 15 24 — — — Variable lease cost 96 4 83 — 5 — Sublease income 1 — — — — — Total lease cost $ 490 $ 78 $ 342 $ 4 $ 38 $ 19 2020 Lease cost Operating lease cost (*) $ 309 $ 55 $ 212 $ 3 $ 29 $ 19 Finance lease cost: Amortization of ROU assets 26 1 15 — — — Interest on lease obligations 11 — 16 — — — Total finance lease cost 37 1 31 — — — Short-term lease costs 39 11 26 — — — Variable lease cost 91 4 76 — 7 — Sublease income — (1) — — — — Total lease cost $ 476 $ 70 $ 345 $ 3 $ 36 $ 19 (*) Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $162 million, $48 million, and $180 million, respectively, in 2022, $165 million, $47 million, and $184 million, respectively, in 2021, and $161 million, $43 million, and $184 million, respectively, in 2020. Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs, including $45 million, $41 million, and $39 million in 2022, 2021, and 2020, respectively, from finance leases which are included in purchased power on Georgia Power's statements of income, of which $21 million, $20 million, and $20 million was included in purchased power, affiliates in 2022, 2021, and 2020, respectively. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2022 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 303 $ 58 $ 206 $ 5 $ 30 $ 14 Operating cash flows from finance leases 11 — 20 1 — — Financing cash flows from finance leases 16 1 10 1 — — ROU assets obtained under operating leases 56 10 17 9 — 3 Reassessment of ROU assets under operating leases 16 — — — 16 — ROU assets obtained under finance leases 118 2 116 — — — 2021 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 308 $ 58 $ 211 $ 2 $ 28 $ 19 Operating cash flows from finance leases 9 — 17 1 — — Financing cash flows from finance leases 17 1 9 1 — — ROU assets obtained under operating leases 64 3 9 — 72 7 ROU assets obtained under finance leases 3 — — — — — 2020 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 310 $ 55 $ 215 $ 3 $ 28 $ 18 Operating cash flows from finance leases 9 — 18 — — — Financing cash flows from finance leases 22 1 11 — — — ROU assets obtained under operating leases 227 63 32 — 51 4 ROU assets obtained under finance leases 10 2 — — — — Southern Alabama Georgia Mississippi Southern Power Southern Company Gas At December 31, 2022 Weighted-average remaining lease term in years: Operating leases 17.3 13.0 8.1 4.7 34.0 11.0 Finance leases 17.4 6.4 11.8 12.9 N/A N/A Weighted-average discount rate: Operating leases 4.51 % 4.87 % 4.52 % 3.49 % 4.86 % 3.79 % Finance leases 4.87 % 3.00 % 8.06 % 2.74 % N/A N/A At December 31, 2021 Weighted-average remaining lease term in years: Operating leases 15.9 9.1 8.7 6.1 32.8 10.5 Finance leases 18.0 8.7 8.5 13.9 N/A N/A Weighted-average discount rate: Operating leases 4.41 % 4.37 % 4.45 % 2.74 % 5.20 % 3.61 % Finance leases 4.82 % 3.09 % 10.81 % 2.74 % N/A N/A Maturities of lease liabilities are as follows: At December 31, 2022 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2023 $ 248 $ 12 $ 191 $ 4 $ 36 $ 11 2024 201 10 165 2 28 11 2025 181 9 138 2 28 11 2026 159 6 135 1 28 8 2027 143 5 135 — 29 3 Thereafter 1,497 64 440 1 1,009 31 Total 2,429 106 1,204 10 1,158 75 Less: Present value discount 844 30 202 1 616 15 Operating lease obligations $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance leases: 2023 $ 33 $ 2 $ 35 $ 2 $ — $ — 2024 22 1 27 2 — — 2025 26 1 35 2 — — 2026 26 1 36 2 — — 2027 26 — 36 2 — — Thereafter 345 — 187 10 — — Total 478 5 356 20 — — Less: Present value discount 164 — 118 3 — — Finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis. Lessor The Registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable Registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to seven years, after which the contracts renew on a month-to-month basis at the customer's option. For Mississippi Power, these arrangements also include a tolling arrangement related to an electric generating unit accounted for as a sales-type lease with a remaining term of 16 years. For Southern Power, these arrangements consist of PPAs related to electric generating units, including solar and wind facilities, accounted for as operating leases with remaining terms of up to 24 years and PPAs related to battery energy storage facilities accounted for as sales-type leases with remaining terms of up to 19 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 20 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with remaining terms of up to 11 years. Lease income for 2022, 2021, and 2020, is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) 2022 Lease income - interest income on sales-type leases $ 25 $ — $ — $ 15 $ 10 $ — Lease income - operating leases 208 77 32 2 85 36 Variable lease income 417 1 — — 448 — Total lease income $ 650 $ 78 $ 32 $ 17 $ 543 $ 36 2021 Lease income - interest income on sales-type leases $ 15 $ — $ — $ 14 $ 1 $ — Lease income - operating leases 223 82 42 2 85 35 Variable lease income 429 — — — 456 — Total lease income $ 667 $ 82 $ 42 $ 16 $ 542 $ 35 2020 Lease income - interest income on sales-type leases $ 16 $ — $ — $ 12 $ — $ — Lease income - operating leases 208 45 58 2 87 35 Variable lease income 419 — — — 449 — Total lease income $ 643 $ 45 $ 58 $ 14 $ 536 $ 35 Lease payments received under tolling arrangements and PPAs consist of either scheduled payments or variable payments based on the amount of energy produced by the underlying electric generating units. Lease income for Alabama Power and Southern Power is included in wholesale revenues. Scheduled payments to be received under outdoor lighting contracts, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses. Mississippi Power has a tolling arrangement accounted for as a sales-type lease. During 2020 and 2021, Mississippi Power completed construction of additional leased assets under the lease and, upon completion, the book values of $26 million and $39 million, respectively, were transferred from CWIP to lease receivables. Each transfer represented a non-cash investing transaction for purposes of the statements of cash flows. During 2021, Southern Power completed construction of a portion of the Garland and Tranquillity battery energy storage facilities' assets and recorded losses totaling $40 million upon commencement of the related PPAs, which Southern Power accounts for as sales-type leases. The losses were due to ITCs retained and expected to be realized by Southern Power and its partners in these projects, and no estimated residual asset value was assumed in calculating the losses. Each lease had an initial term of 20 years. Upon commencement of the leases, the book values of the related assets totaling $210 million were derecognized from CWIP and lease receivables were recorded. The transfers represented noncash investing transactions for purposes of the statement of cash flows. See Note 15 under "Southern Power" for additional information. The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows: At December 31, 2022 Southern Company Mississippi Power Southern (in millions) 2023 $ 39 $ 24 $ 15 2024 38 23 15 2025 37 22 15 2026 36 21 15 2027 35 20 15 Thereafter 364 164 200 Total undiscounted cash flows $ 549 $ 274 $ 275 Net investment in sales-type lease (*) 326 157 169 Difference between undiscounted cash flows and discounted cash flows $ 223 $ 117 $ 106 (*) For Mississippi Power, included in other current assets and other property and investments on the balance sheets. For Southern Power, included in other current assets ($15 million and $12 million at December 31, 2022 and 2021, respectively) and net investment in sales-type leases ($154 million and $161 million at December 31, 2022 and 2021, respectively) on the balance sheet. The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows: At December 31, 2022 Southern Alabama Southern Southern Company Gas (in millions) 2023 $ 145 $ 34 $ 88 $ 36 2024 114 6 90 34 2025 105 5 74 29 2026 104 3 73 29 2027 104 3 74 28 Thereafter 796 23 166 382 Total $ 1,368 $ 74 $ 565 $ 538 Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Alabama Power and Southern Power allocate revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under outdoor lighting contracts accounted for as operating leases at Georgia Power and Mississippi Power are immaterial. Southern Company Leveraged Lease At December 31, 2020, a subsidiary of Southern Holdings had four leveraged lease agreements related to energy generation, distribution, and transportation assets, including two domestic and two international projects. During 2021, one of the domestic projects was sold and the agreements for both international projects were terminated. At December 31, 2022, the one remaining leveraged lease agreement, which relates to energy generation, had an expected remaining term of nine years. Southern Company continues to receive federal income tax deductions for depreciation and amortization, as well as interest on long-term debt related to this investment. Southern Company wrote off the related investment balance in 2020, as discussed below. During the second quarter 2020, following an evaluation of the recoverability of the lease receivable and the expected residual value of the generation assets at the end of the lease, Southern Company management concluded it was no longer probable that any of the associated rental payments scheduled after 2032 would be received, because it was no longer probable the generation assets would be successfully remarketed and continue to operate after that date. Revising the estimated cash flows to be received under the leveraged lease to reflect this conclusion resulted in a full impairment of the lease investment and a pre-tax charge to earnings of $154 million ($74 million after tax). The following table provides a summary of the components of income related to leveraged lease investments. Income was impacted in 2021 and 2020 by the impairment charges discussed below and in Note 15 under "Southern Company." Income in 2021 does not include the impacts of the sale and terminations of leveraged lease projects discussed in Note 15 under "Southern Company." 2021 2020 (in millions) Pretax leveraged lease income (loss) $ 17 $ (180) Income tax benefit (expense) (5) 98 Net leveraged lease income (loss) $ 12 $ (82) On June 30, 2022, the Southern Holdings subsidiary operating the generating plant for the lessee provided notice to the lessee to terminate the related operating and maintenance agreement effective June 30, 2023. The parties to the lease agreement are currently negotiating a potential restructuring, which could result in rescission of the termination notice. The ultimate outcome of this matter cannot be determined at this time but is not expected to have a material impact on Southern Company's financial statements. The lessee failed to make the semi-annual lease payment due December 15, 2022. As a result, the Southern Holdings subsidiary was unable to make its corresponding payment to the holders of the underlying non-recourse debt related to the generation assets. The parties to the lease have entered into a forbearance agreement which suspends the related contractual rights of the parties while they continue restructuring negotiations. As the remaining amount of Southern Company's lease investment was charged against earnings in the second quarter 2020, termination would not be expected to result in additional charges. Southern Company will continue to monitor the operational performance of the underlying assets and evaluate the ability of the lessee to continue to make the required lease payments and meet its obligations associated with a future closure or retirement of the generation assets and associated properties, including the dry ash landfill.

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
INCOME TAXES	INCOME TAXESSouthern Company files a consolidated federal income tax return and the Registrants file various state income tax returns, some of which are combined or unitary. Under a joint consolidated income tax allocation agreement, each Southern Company subsidiary's current and deferred tax expense is computed on a stand-alone basis, and each subsidiary is allocated an amount of tax similar to that which would be paid if it filed a separate income tax return. In accordance with IRS regulations, each company is jointly and severally liable for the federal tax liability. Current and Deferred Income Taxes Details of income tax provisions are as follows: 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Federal — Current $ 10 $ 54 $ 38 $ 42 $ (43) $ 122 Deferred 455 259 152 (16) 56 (3) 465 313 190 26 13 119 State — Current 27 14 (21) — 2 42 Deferred 303 96 201 11 5 19 330 110 180 11 7 61 Total $ 795 $ 423 $ 370 $ 37 $ 20 $ 180 2021 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Federal — Current $ 50 $ 104 $ 311 $ 25 $ (340) $ 85 Deferred 36 172 (449) (15) 343 35 86 276 (138) 10 3 120 State — Current (25) 23 71 — (16) (68) Deferred 206 73 (101) 11 — 223 181 96 (30) 11 (16) 155 Total $ 267 $ 372 $ (168) $ 21 $ (13) $ 275 2020 Southern Company Alabama Power Georgia Mississippi Southern Power Southern Company Gas (in millions) Federal — Current $ 199 $ 198 $ 365 $ 18 $ (303) $ 82 Deferred 70 44 (224) (14) 299 53 269 242 141 4 (4) 135 State — Current 100 61 60 — (4) 35 Deferred 24 34 (49) 10 11 3 124 95 11 10 7 38 Total $ 393 $ 337 $ 152 $ 14 $ 3 $ 173 Southern Company's and Southern Power's ITCs and PTCs generated in the current tax year and carried forward from prior tax years that cannot be utilized in the current tax year are reclassified from current to deferred taxes in federal income tax expense in the tables above. Southern Power's ITCs and PTCs reclassified in this manner include $17 million for 2022, $6 million for 2021, and $5 million for 2020. Southern Power received $49 million, $289 million, and $340 million of cash related to federal ITCs under renewable energy initiatives in 2022, 2021, and 2020, respectively. See "Deferred Tax Assets and Liabilities" herein for additional information. In accordance with regulatory requirements, deferred federal ITCs for the traditional electric operating companies are amortized over the average life of the related property, with such amortization normally applied as a credit to reduce depreciation and amortization in the statements of income. Southern Power's and the natural gas distribution utilities' deferred federal ITCs, as well as certain state ITCs for Nicor Gas, are amortized to income tax expense over the life of the respective asset. ITCs amortized in 2022, 2021, and 2020 were immaterial for the traditional electric operating companies and Southern Company Gas and were as follows for Southern Company and Southern Power: Southern Company Southern Power (in millions) 2022 $ 83 $ 58 2021 84 58 2020 84 59 When Southern Power recognizes tax credits, the tax basis of the asset is reduced by 50% of the ITCs received, resulting in a net deferred tax asset. Southern Power has elected to recognize the tax benefit of this basis difference as a reduction to income tax expense in the year in which the plant reaches commercial operation. State ITCs and other state credits, which are recognized in the period in which the credits are generated, reduced Georgia Power's income tax expense by $53 million in 2022, $66 million in 2021, and $67 million in 2020. Southern Power's federal and state PTCs, which are recognized in the period in which the credits are generated, reduced Southern Power's income tax expense by $27 million in 2022, $16 million in 2021, and $15 million in 2020. Effective Tax Rate Southern Company's effective tax rate is typically lower than the statutory rate due to employee stock plans' dividend deduction, non-taxable AFUDC equity at the traditional electric operating companies, flowback of excess deferred income taxes at the regulated utilities, and federal income tax benefits from ITCs and PTCs primarily at Southern Power. In July 2021, Southern Company Gas affiliates completed the sale of Sequent. As a result of the sale, changes in state apportionment rates resulted in $85 million of additional net state tax expense. See Note 15 under "Southern Company Gas" for additional information. A reconciliation of the federal statutory income tax rate to the effective income tax rate is as follows: 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Federal statutory rate 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % State income tax, net of federal deduction 6.2 4.8 6.5 4.4 1.9 6.4 Employee stock plans' dividend deduction (0.5) — — — — — Non-deductible book depreciation 0.6 0.5 0.6 0.3 — — Flowback of excess deferred income taxes (6.6) (1.9) (9.6) (7.8) — (2.5) AFUDC-Equity (1.1) (0.8) (1.5) — — — Federal PTCs — — — — (6.6) — ITC amortization (1.3) (0.1) (0.1) — (17.2) (0.1) Noncontrolling interests 0.5 — — — 8.4 — Other — 0.3 — 0.3 (0.1) (0.9) Effective income tax (benefit) rate 18.8 % 23.8 % 16.9 % 18.2 % 7.4 % 23.9 % 2021 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Federal statutory rate 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % State income tax, net of federal deduction 5.5 4.6 (5.7) 4.9 (8.0) 15.1 Employee stock plans' dividend deduction (0.9) — — — — — Non-deductible book depreciation 0.9 0.5 3.1 0.4 — — Flowback of excess deferred income taxes (11.7) (2.6) (49.9) (15.2) — (2.8) AFUDC-Equity (1.5) (0.7) (6.4) — — — Federal PTCs — — — — (4.6) — ITC amortization (2.2) (0.1) (0.4) — (29.7) (0.1) Noncontrolling interests 0.8 — — — 13.4 — Leveraged lease impairments and dispositions (1.4) — — — — — Other (0.1) 0.2 (1.9) 0.6 (0.4) 0.6 Effective income tax (benefit) rate 10.4 % 22.9 % (40.2) % 11.7 % (8.3) % 33.8 % 2020 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Federal statutory rate 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % State income tax, net of federal deduction 2.8 5.0 0.5 4.8 2.7 4.0 Employee stock plans' dividend deduction (0.7) — — — — — Non-deductible book depreciation 0.7 0.6 0.8 0.5 — — Flowback of excess deferred income taxes (8.8) (3.1) (12.0) (18.5) — (2.7) AFUDC-Equity (0.8) (0.6) (1.1) (0.1) — — Federal PTCs — — — — (2.5) — ITC amortization (1.6) (0.1) (0.1) (0.1) (22.1) (0.1) Noncontrolling interests — — — — 3.1 — Leveraged lease impairments (1.6) — — — — — Other 0.2 (0.3) (0.3) 0.9 (0.9) 0.5 Effective income tax (benefit) rate 11.2 % 22.5 % 8.8 % 8.5 % 1.3 % 22.7 % Deferred Tax Assets and Liabilities The tax effects of temporary differences between the carrying amounts of assets and liabilities in the financial statements of the Registrants and their respective tax bases, which give rise to deferred tax assets and liabilities, are as follows: December 31, 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Deferred tax liabilities — Accelerated depreciation $ 9,443 $ 2,564 $ 3,447 $ 338 $ 1,351 $ 1,505 Property basis differences 2,350 1,303 693 179 — 150 Employee benefit obligations 888 284 412 43 11 68 AROs 876 499 324 — — — Under recovered fuel and natural gas costs 805 185 548 40 — 32 Regulatory assets – AROs 2,006 679 1,285 42 — — Employee benefit obligations 677 180 226 30 — 15 Remaining book value of retired assets 400 142 253 5 — — Premium on reacquired debt 66 9 57 — — — Other 555 179 181 40 14 82 Total deferred income tax liabilities 18,066 6,024 7,426 717 1,376 1,852 Deferred tax assets — AROs 2,882 1,178 1,609 42 — — ITC and PTC carryforwards 1,685 12 673 — 794 — Employee benefit obligations 890 198 304 47 9 89 Estimated loss on plants under construction 888 — 888 — — — Other state deferred tax attributes 388 — 12 239 51 7 Federal effect of net state deferred tax liabilities 365 175 88 — 28 92 Other property basis differences 207 — 79 — 109 — State effect of federal deferred taxes 136 136 — — — — Other partnership basis differences 111 — — — 111 — Regulatory liability associated with the Tax Reform Legislation (not subject to normalization) 137 127 — 9 — — Long-term debt fair value adjustment 85 — — — — 85 Other comprehensive losses 72 4 5 — 5 — Other 552 213 186 62 17 28 Total deferred income tax assets 8,398 2,043 3,844 399 1,124 301 Valuation allowance (257) — (125) (41) (27) (9) Net deferred income tax assets 8,141 2,043 3,719 358 1,097 292 Net deferred income taxes (assets)/liabilities $ 9,925 $ 3,981 $ 3,707 $ 359 $ 279 $ 1,560 Recognized in the balance sheets: Accumulated deferred income taxes – assets $ (111) $ — $ — $ (107) $ — $ — Accumulated deferred income taxes – liabilities $ 10,036 $ 3,981 $ 3,707 $ 466 $ 279 $ 1,560 December 31, 2021 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Deferred tax liabilities — Accelerated depreciation $ 9,300 $ 2,541 $ 3,340 $ 330 $ 1,421 $ 1,428 Property basis differences 2,301 1,182 781 169 — 148 Federal effect of net state deferred tax assets — — — 22 — — Leveraged lease basis differences 61 — — — — — Employee benefit obligations 820 268 382 41 11 57 AROs 868 329 494 — — — Under recovered fuel and natural gas costs 315 47 109 15 — 144 Regulatory assets – AROs 2,232 863 1,325 44 — — Storm damage reserves 18 — 18 — — — Employee benefit obligations 825 205 256 38 — 15 Remaining book value of retired assets 271 145 121 5 — — Premium on reacquired debt 72 10 62 — — — Other 368 147 77 34 14 82 Total deferred income tax liabilities 17,451 5,737 6,965 698 1,446 1,874 Deferred tax assets — AROs 3,100 1,192 1,819 44 — — ITC and PTC carryforwards 1,750 12 704 — 827 — Employee benefit obligations 1,035 225 342 57 7 77 Estimated loss on plants under construction 825 — 825 — — — Other state deferred tax attributes 361 — 11 246 52 5 Federal effect of net state deferred tax liabilities 305 165 41 — 27 93 Other property basis differences 231 — 90 — 121 — State effect of federal deferred taxes 135 135 — — — — Other partnership basis differences 160 — — — 160 — Regulatory liability associated with the Tax Reform Legislation (not subject to normalization) 268 237 19 12 — — Long-term debt fair value adjustment 91 — — — — 91 Other comprehensive losses 92 5 15 — 11 — Other 561 193 153 34 53 62 Total deferred income tax assets 8,914 2,164 4,019 393 1,258 328 Valuation allowance (207) — (73) (41) (27) (9) Net deferred income tax assets 8,707 2,164 3,946 352 1,231 319 Net deferred income taxes (assets)/liabilities $ 8,744 $ 3,573 $ 3,019 $ 346 $ 215 $ 1,555 Recognized in the balance sheets: Accumulated deferred income taxes – assets $ (118) $ — $ — $ (118) $ — $ — Accumulated deferred income taxes – liabilities $ 8,862 $ 3,573 $ 3,019 $ 464 $ 215 $ 1,555 The traditional electric operating companies and the natural gas distribution utilities have tax-related regulatory assets (deferred income tax charges) and regulatory liabilities (deferred income tax credits). The regulatory assets are primarily attributable to tax benefits flowed through to customers in prior years, deferred taxes previously recognized at rates lower than the current enacted tax law, and taxes applicable to capitalized interest. The regulatory liabilities are primarily attributable to deferred taxes previously recognized at rates higher than the current enacted tax law and to unamortized ITCs. See Note 2 for each Registrant's related balances at December 31, 2022 and 2021. Tax Credit Carryforwards Federal ITC/PTC carryforwards at December 31, 2022 were as follows: Southern Company Alabama Georgia Southern (in millions) Federal ITC/PTC carryforwards $ 1,148 $ 12 $ 135 $ 794 Tax year in which federal ITC/PTC carryforwards begin expiring 2031 2032 2031 2035 Year by which federal ITC/PTC carryforwards are expected to be utilized 2026 2025 2025 2026 The estimated tax credit utilization reflects the various sale transactions described in Note 15 and could be further delayed by numerous factors, including the acquisition of additional renewable projects, the purchase of rights to additional PTCs of Plant Vogtle Units 3 and 4 pursuant to certain joint ownership agreements, an increase in Georgia Power's ownership interest percentage in Plant Vogtle Units 3 and 4, changes in taxable income projections, and potential income tax rate changes. See Note 2 under "Georgia Power – Nuclear Construction" for additional information on Plant Vogtle Units 3 and 4. At December 31, 2022, Georgia Power also had approximately $434 million in net state investment and other net state tax credit carryforwards for the State of Georgia that will expire between tax years 2022 and 2031 and are not expected to be fully utilized. Georgia Power has a net state valuation allowance of $98 million associated with these carryforwards. The ultimate outcome of these matters cannot be determined at this time. Net Operating Loss Carryforwards At December 31, 2022, the net state income tax benefit of state and local NOL carryforwards for Southern Company's subsidiaries were as follows: Company/Jurisdiction Approximate Net State Income Tax Benefit of NOL Carryforwards Tax Year NOL (in millions) Mississippi Power Mississippi $ 189 2031 Southern Power Oklahoma 27 2035 Florida 10 2034 Other states 3 Various Southern Power Total $ 40 Other (*) Georgia 23 2042 New York 11 2036 New York City 14 2036 Other states 21 Various Southern Company Total $ 298 (*) Represents other non-registrant Southern Company subsidiaries. Alabama Power, Georgia Power, and Southern Company Gas did not have material state or local NOL carryforwards at December 31, 2022. State NOLs for Mississippi, Oklahoma, and Florida are not expected to be fully utilized prior to expiration. At December 31, 2022, Mississippi Power had a net state valuation allowance of $32 million for the Mississippi NOL, Southern Power had net state valuation allowances of $11 million for the Oklahoma NOL and $10 million for the Florida NOL, and Southern Company had a net valuation allowance of $25 million for the New York and New York City NOLs. The ultimate outcome of these matters cannot be determined at this time. Unrecognized Tax Benefits Changes in unrecognized tax benefits for the periods presented were as follows: Southern Company Southern (in millions) Unrecognized tax benefits at December 31, 2019 $ — $ — Tax positions changes – increase from prior periods 44 — Unrecognized tax benefits at December 31, 2020 $ 44 $ — Tax positions changes – increase from prior periods 3 — Unrecognized tax benefits at December 31, 2021 $ 47 $ — Tax positions changes – increase from prior periods 33 32 Unrecognized tax benefits at December 31, 2022 $ 80 $ 32 The unrecognized tax positions increase from prior periods for 2020 primarily relates to a 2019 state tax filing position to exclude certain gains from 2019 dispositions from taxation in a certain unitary state. It is possible that this position will be resolved in the next 12 months, and if accepted by the state, this position would decrease Southern Company's annual effective tax rate. The unrecognized tax positions increase from prior periods for 2022 is primarily related to the amendment of certain 2018 state tax filing positions related to Southern Company Gas dispositions. If accepted by the states, these positions would decrease Southern Company's and Southern Company Gas' annual effective tax rates. The ultimate outcome of these unrecognized tax benefits is dependent on acceptance by each state and is not expected to be resolved within the next 12 months. All of the Registrants classify interest on tax uncertainties as interest expense. Accrued interest for all tax positions was immaterial for all years presented. None of the Registrants accrued any penalties on uncertain tax positions. The IRS has finalized its audits of Southern Company's consolidated federal income tax returns through 2021. Southern Company is a participant in the Compliance Assurance Process of the IRS. The audits for the Registrants' state income tax returns have either been concluded, or the statute of limitations has expired, for years prior to 2015.

RETIREMENT BENEFITS

RETIREMENT BENEFITS	12 Months Ended
	Dec. 31, 2022
Retirement Benefits [Abstract]
RETIREMENT BENEFITS	RETIREMENT BENEFITSThe Southern Company system has a qualified defined benefit, trusteed pension plan covering substantially all employees, with the exception of PowerSecure employees. The qualified pension plan is funded in accordance with requirements of the Employee Retirement Income Security Act of 1974, as amended (ERISA). No contributions to the qualified pension plan were made for the year ended December 31, 2022 and no mandatory contributions to the qualified pension plan are anticipated for the year ending December 31, 2023. The Southern Company system also provides certain non-qualified defined benefits for a select group of management and highly compensated employees, which are funded on a cash basis. In addition, the Southern Company system provides certain medical care and life insurance benefits for retired employees through other postretirement benefit plans. The traditional electric operating companies fund other postretirement trusts to the extent required by their respective regulatory commissions. Southern Company Gas has a separate unfunded supplemental retirement health care plan that provides medical care and life insurance benefits to employees of discontinued businesses. For the year ending December 31, 2023, no contributions to any other postretirement trusts are expected. Actuarial Assumptions The weighted average rates assumed in the actuarial calculations used to determine both the net periodic costs for the pension and other postretirement benefit plans for the following year and the benefit obligations as of the measurement date are presented below. 2022 Assumptions used to determine net Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate – benefit obligations 3.09 % 3.12 % 3.07 % 3.07 % 3.21 % 3.04 % Discount rate – interest costs 2.55 2.58 2.51 2.54 2.79 2.53 Discount rate – service costs 3.34 3.36 3.37 3.35 3.36 3.21 Expected long-term return on plan assets 8.25 8.25 8.25 8.25 8.25 8.25 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate – benefit obligations 2.90 % 2.95 % 2.87 % 2.88 % 3.07 % 2.82 % Discount rate – interest costs 2.32 2.38 2.30 2.27 2.55 2.17 Discount rate – service costs 3.26 3.30 3.27 3.26 3.25 3.22 Expected long-term return on plan assets 7.21 7.54 6.88 7.22 — 6.08 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 2021 Assumptions used to determine net Southern Company Alabama Georgia Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate – benefit obligations 2.81 % 2.85 % 2.79 % 2.80 % 2.99 % 2.75 % Discount rate – interest costs 2.13 2.17 2.09 2.12 2.46 2.10 Discount rate – service costs 3.18 3.23 3.21 3.20 3.22 2.97 Expected long-term return on plan assets 8.25 8.25 8.25 8.25 8.25 8.25 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate – benefit obligations 2.56 % 2.63 % 2.52 % 2.53 % 2.78 % 2.46 % Discount rate – interest costs 1.84 1.91 1.82 1.78 2.12 1.64 Discount rate – service costs 3.07 3.13 3.08 3.06 3.05 3.01 Expected long-term return on plan assets 7.09 7.18 6.84 6.98 — 6.54 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 2020 Assumptions used to determine net periodic costs: Southern Company Alabama Georgia Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate – benefit obligations 3.41 % 3.44 % 3.40 % 3.41 % 3.52 % 3.39 % Discount rate – interest costs 2.99 3.01 2.96 2.99 3.18 2.99 Discount rate – service costs 3.66 3.69 3.67 3.67 3.70 3.53 Expected long-term return on plan assets 8.25 8.25 8.25 8.25 8.25 8.25 Annual salary increase 4.73 4.73 4.73 4.73 4.73 4.73 Other postretirement benefit plans Discount rate – benefit obligations 3.24 % 3.28 % 3.22 % 3.22 % 3.39 % 3.19 % Discount rate – interest costs 2.80 2.84 2.79 2.76 2.97 2.71 Discount rate – service costs 3.57 3.61 3.57 3.57 3.57 3.52 Expected long-term return on plan assets 7.25 7.36 7.05 7.07 — 6.69 Annual salary increase 4.73 4.73 4.73 4.73 4.73 4.73 2022 Assumptions used to determine benefit obligations: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate 5.25 % 5.26 % 5.25 % 5.25 % 5.31 % 5.24 % Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate 5.18 % 5.20 % 5.17 % 5.17 % 5.24 % 5.16 % Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 2021 Assumptions used to determine benefit obligations: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate 3.09 % 3.12 % 3.07 % 3.07 % 3.21 % 3.04 % Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate 2.90 % 2.95 % 2.87 % 2.88 % 3.07 % 2.82 % Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 The Registrants estimate the expected rate of return on pension plan and other postretirement benefit plan assets using a financial model to project the expected return on each current investment portfolio. The analysis projects an expected rate of return on each of the different asset classes in order to arrive at the expected return on the entire portfolio relying on each trust's target asset allocation and reasonable capital market assumptions. The financial model is based on four key inputs: anticipated returns by asset class (based in part on historical returns), each trust's target asset allocation, an anticipated inflation rate, and the projected impact of a periodic rebalancing of each trust's portfolio. The Registrants set the expected rate of return assumption using an arithmetic mean which represents the expected simple average return to be earned by the pension plan assets over any one year. The Registrants believe the use of the arithmetic mean is more compatible with the expected rate of return's function of estimating a single year's investment return. An additional assumption used in measuring the accumulated other postretirement benefit obligations (APBO) was a weighted average medical care cost trend rate. The weighted average medical care cost trend rates used in measuring the APBO for the Registrants at December 31, 2022 were as follows: Initial Cost Trend Rate Ultimate Cost Trend Rate Year That Ultimate Rate is Reached Pre-65 6.60 % 4.50 % 2030 Post-65 medical 5.50 4.50 2030 Post-65 prescription 7.50 4.50 2031 Pension Plans The total accumulated benefit obligation for the pension plans at December 31, 2022 and 2021 was as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) December 31, 2022 $ 11,422 $ 2,601 $ 3,534 $ 520 $ 135 $ 801 December 31, 2021 14,687 3,362 4,562 672 178 1,030 Actuarial gains of $3.9 billion and $393 million were recorded for the annual remeasurement of the Southern Company system pension plans at December 31, 2022 and 2021, respectively, primarily due to increases of 216 basis points and 28 basis points, respectively, in the overall discount rate used to calculate the benefit obligation as a result of higher market interest rates. Changes in the projected benefit obligations and the fair value of plan assets during the plan years ended December 31, 2022 and 2021 were as follows: 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 16,382 $ 3,806 $ 5,012 $ 743 $ 222 $ 1,134 Service cost 412 99 103 17 9 34 Interest cost 408 96 123 18 6 28 Benefits paid (692) (144) (226) (30) (5) (75) Actuarial gain (3,908) (951) (1,161) (179) (69) (253) Balance at end of year 12,602 2,906 3,851 569 163 868 Change in plan assets Fair value of plan assets at beginning of year 17,225 4,141 5,415 786 213 1,241 Actual loss on plan assets (2,376) (579) (753) (110) (31) (167) Employer contributions 61 9 20 3 1 3 Benefits paid (692) (144) (226) (30) (5) (75) Fair value of plan assets at end of year 14,218 3,427 4,456 649 178 1,002 Accrued asset $ 1,616 $ 521 $ 605 $ 80 $ 15 $ 134 2021 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 16,646 $ 3,854 $ 5,127 $ 754 $ 217 $ 1,189 Service cost 434 102 112 18 10 37 Interest cost 346 82 104 16 5 24 Benefits paid (651) (137) (210) (28) (4) (73) Actuarial gain (393) (95) (121) (17) (6) (43) Balance at end of year 16,382 3,806 5,012 743 222 1,134 Change in plan assets Fair value of plan assets at beginning of year 15,367 3,684 4,844 701 186 1,123 Actual return on plan assets 2,449 586 781 111 30 181 Employer contributions 60 8 — 2 1 10 Benefits paid (651) (137) (210) (28) (4) (73) Fair value of plan assets at end of year 17,225 4,141 5,415 786 213 1,241 Accrued asset (liability) $ 843 $ 335 $ 403 $ 43 $ (9) $ 107 The projected benefit obligations for the qualified and non-qualified pension plans at December 31, 2022 are shown in the following table. All pension plan assets are related to the qualified pension plan. Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Projected benefit obligations: Qualified pension plan $ 11,928 $ 2,799 $ 3,717 $ 540 $ 140 $ 819 Non-qualified pension plan 674 107 134 28 23 49 Amounts recognized in the balance sheets at December 31, 2022 and 2021 related to the Registrants' pension plans consist of the following: Southern Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) December 31, 2022: Prepaid pension costs (a) $ 2,290 $ 629 $ 738 $ 108 $ 37 $ 183 Other regulatory assets, deferred (b) 2,455 679 887 123 — 111 Other current liabilities (56) (10) (12) (2) (2) (3) Employee benefit obligations (c) (618) (98) (121) (26) (20) (42) Other regulatory liabilities, deferred (85) — — — — — AOCI 24 — — — 11 (75) December 31, 2021: Prepaid pension costs (a) $ 1,657 $ 464 $ 563 $ 78 $ 20 $ 175 Other regulatory assets, deferred (b) 2,920 809 971 146 — 91 Other current liabilities (55) (9) (12) (2) (2) (2) Employee benefit obligations (c) (759) (120) (148) (33) (27) (66) Other regulatory liabilities, deferred (119) — — — — — AOCI 100 — — — 35 (45) (a) Included in prepaid pension and other postretirement benefit costs on Alabama Power's balance sheet and other deferred charges and assets on Southern Power's consolidated balance sheet. (b) Amounts for Southern Company exclude regulatory assets of $190 million and $210 million at December 31, 2022 and 2021, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company. (c) Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets. Presented below are the amounts included in regulatory assets at December 31, 2022 and 2021 related to the portion of the defined benefit pension plan attributable to Southern Company, the traditional electric operating companies, and Southern Company Gas that had not yet been recognized in net periodic pension cost. Southern Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Balance at December 31, 2022 Regulatory assets: Prior service cost $ 10 $ 4 $ 7 $ 1 $ (9) Net loss 2,361 675 880 122 66 Regulatory amortization — — — — 54 Total regulatory assets (*) $ 2,371 $ 679 $ 887 $ 123 $ 111 Balance at December 31, 2021 Regulatory assets: Prior service cost $ 11 $ 5 $ 8 $ 1 $ (11) Net loss 2,790 804 963 145 38 Regulatory amortization — — — — 64 Total regulatory assets (*) $ 2,801 $ 809 $ 971 $ 146 $ 91 (*) Amounts for Southern Company exclude regulatory assets of $190 million and $210 million at December 31, 2022 and 2021, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company. The changes in the balance of regulatory assets related to the portion of the defined benefit pension plan attributable to Southern Company, the traditional electric operating companies, and Southern Company Gas for the years ended December 31, 2022 and 2021 are presented in the following table: Southern Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Regulatory assets (liabilities): (*) Balance at December 31, 2020 $ 4,621 $ 1,286 $ 1,598 $ 235 $ 205 Net gain (1,523) (394) (527) (74) (97) Reclassification adjustments: Amortization of prior service costs (1) (1) (1) — 2 Amortization of net loss (296) (82) (99) (15) (9) Amortization of regulatory assets (*) — — — — (10) Total reclassification adjustments (297) (83) (100) (15) (17) Total change (1,820) (477) (627) (89) (114) Balance at December 31, 2021 $ 2,801 $ 809 $ 971 $ 146 $ 91 Net (gain) loss (183) (67) (9) (12) 27 Reclassification adjustments: Amortization of prior service costs (1) (1) (1) — 2 Amortization of net gain (loss) (246) (62) (74) (11) 1 Amortization of regulatory assets (*) — — — — (10) Total reclassification adjustments (247) (63) (75) (11) (7) Total change (430) (130) (84) (23) 20 Balance at December 31, 2022 $ 2,371 $ 679 $ 887 $ 123 $ 111 (*) Amounts for Southern Company exclude regulatory assets of $190 million and $210 million at December 31, 2022 and 2021, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company. Presented below are the amounts included in AOCI at December 31, 2022 and 2021 related to the portion of the defined benefit pension plan attributable to Southern Company, Southern Power, and Southern Company Gas that had not yet been recognized in net periodic pension cost. Southern Southern Southern Company (in millions) Balance at December 31, 2022 AOCI: Prior service cost $ (2) $ — $ (3) Net (gain) loss 26 11 (72) Total AOCI $ 24 $ 11 $ (75) Balance at December 31, 2021 AOCI: Prior service cost $ (2) $ — $ (3) Net (gain) loss 102 35 (42) Total AOCI $ 100 $ 35 $ (45) The components of OCI related to the portion of the defined benefit pension plan attributable to Southern Company, Southern Power, and Southern Company Gas for the years ended December 31, 2022 and 2021 are presented in the following table: Southern Company Southern Southern Company (in millions) AOCI: Balance at December 31, 2020 $ 245 $ 60 $ 1 Net gain (128) (22) (47) Reclassification adjustments: Amortization of net gain (loss) (17) (3) 1 Total change (145) (25) (46) Balance at December 31, 2021 $ 100 $ 35 $ (45) Net gain (82) (22) (30) Reclassification adjustments: Amortization of net gain (loss) 6 (2) — Total reclassification adjustments 6 (2) — Total change (76) (24) (30) Balance at December 31, 2022 $ 24 $ 11 $ (75) Components of net periodic pension cost for the Registrants were as follows: Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) 2022 Service cost $ 412 $ 99 $ 103 $ 17 $ 9 $ 34 Interest cost 408 96 123 18 6 28 Expected return on plan assets (1,265) (306) (399) (57) (15) (91) Recognized net loss 240 62 75 11 2 8 Net amortization — 1 1 — — 15 Prior service cost — — — — — (3) Net periodic pension cost (income) $ (205) $ (48) $ (97) $ (11) $ 2 $ (9) 2021 Service cost $ 434 $ 102 $ 112 $ 18 $ 10 $ 37 Interest cost 346 82 104 16 5 24 Expected return on plan assets (1,191) (287) (375) (55) (14) (86) Recognized net loss 314 82 100 15 3 13 Net amortization 1 1 1 — — 15 Prior service cost — — — — — (3) Net periodic pension cost (income) $ (96) $ (20) $ (58) $ (6) $ 4 $ — 2020 Service cost $ 376 $ 89 $ 96 $ 15 $ 8 $ 33 Interest cost 432 100 133 20 6 31 Expected return on plan assets (1,100) (264) (347) (51) (13) (75) Recognized net loss 269 71 86 13 2 6 Net amortization 1 1 1 — — 15 Prior service cost — — — — — (3) Net periodic pension cost (income) $ (22) $ (3) $ (31) $ (3) $ 3 $ 7 The service cost component of net periodic pension cost is included in operations and maintenance expenses and all other components of net periodic pension cost are included in other income (expense), net in the Registrants' statements of income. Net periodic pension cost is the sum of service cost, interest cost, and other costs netted against the expected return on plan assets. The expected return on plan assets is determined by multiplying the expected rate of return on plan assets and the market-related value of plan assets. In determining the market-related value of plan assets, the Registrants have elected to amortize changes in the market value of return-seeking plan assets over five years and to recognize the changes in the market value of liability-hedging plan assets immediately. Given the significant concentration in return-seeking plan assets, the accounting value of plan assets that is used to calculate the expected return on plan assets differs from the current fair value of the plan assets. Future benefit payments reflect expected future service and are estimated based on assumptions used to measure the projected benefit obligation for the pension plans. At December 31, 2022, estimated benefit payments were as follows: Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Benefit Payments: 2023 $ 734 $ 155 $ 230 $ 32 $ 6 $ 83 2024 735 160 236 33 7 57 2025 760 167 243 34 7 58 2026 784 173 248 35 7 60 2027 806 178 252 36 8 61 2028 to 2032 4,262 952 1,304 192 43 323 Other Postretirement Benefits Changes in the APBO and the fair value of the Registrants' plan assets during the plan years ended December 31, 2022 and 2021 were as follows: 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 1,849 $ 440 $ 656 $ 76 $ 11 $ 237 Service cost 23 6 6 1 — 1 Interest cost 42 10 15 2 — 5 Benefits paid (109) (23) (38) (4) (1) (18) Actuarial gain (365) (89) (125) (16) (1) (46) Retiree drug subsidy 1 — — — — — Balance at end of year 1,441 344 514 59 9 179 Change in plan assets Fair value of plan assets at beginning of year 1,251 489 450 29 — 143 Actual loss on plan assets (218) (98) (71) (4) — (25) Employer contributions 73 4 27 3 1 13 Benefits paid (108) (23) (38) (4) (1) (18) Fair value of plan assets at end of year 998 372 368 24 — 113 Accrued asset (liability) $ (443) $ 28 $ (146) $ (35) $ (9) $ (66) 2021 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 1,948 $ 463 $ 699 $ 81 $ 12 $ 248 Service cost 24 6 7 1 — 2 Interest cost 35 9 12 1 — 4 Benefits paid (105) (22) (36) (5) — (18) Actuarial (gain) loss (54) (16) (26) (2) (1) 1 Retiree drug subsidy 1 — — — — — Balance at end of year 1,849 440 656 76 11 237 Change in plan assets Fair value of plan assets at beginning of year 1,158 458 427 27 — 128 Actual return on plan assets 154 55 55 4 — 18 Employer contributions 43 (2) 4 3 — 15 Benefits paid (104) (22) (36) (5) — (18) Fair value of plan assets at end of year 1,251 489 450 29 — 143 Accrued asset (liability) $ (598) $ 49 $ (206) $ (47) $ (11) $ (94) Amounts recognized in the balance sheets at December 31, 2022 and 2021 related to the Registrants' other postretirement benefit plans consist of the following: Southern Company Alabama Power Georgia Mississippi Power Southern Southern Company Gas (in millions) December 31, 2022: Prepaid other postretirement benefit costs (a) $ — $ 28 $ — $ — $ — $ — Other regulatory assets, deferred (b) 34 — 19 — — — Other current liabilities (6) — — — (1) — Employee benefit obligations (c) (437) — (146) (35) (8) (66) Other regulatory liabilities, deferred (170) (21) (58) (9) — (58) AOCI (4) — — — — (2) December 31, 2021: Prepaid other postretirement benefit costs (a) $ — $ 49 $ — $ — $ — $ — Other regulatory assets, deferred (b) 97 — 30 2 — — Other current liabilities (5) — — — — — Employee benefit obligations (c) (593) — (206) (47) (11) (94) Other regulatory liabilities, deferred (171) (62) (40) (1) — (34) AOCI — — — — 2 (5) (a) Included in prepaid pension and other postretirement benefit costs on Alabama Power's balance sheet. (b) Amounts for Southern Company exclude regulatory assets of $32 million and $40 million at December 31, 2022 and 2021, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company. (c) Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets. Presented below are the amounts included in net regulatory assets (liabilities) at December 31, 2022 and 2021 related to the other postretirement benefit plans of Southern Company, the traditional electric operating companies, and Southern Company Gas that had not yet been recognized in net periodic other postretirement benefit cost. Southern Company Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Balance at December 31, 2022: Regulatory assets (liabilities): Prior service cost $ 14 $ 4 $ 6 $ 1 $ 1 Net gain (150) (25) (45) (10) (64) Regulatory amortization — — — — 5 Total regulatory assets (liabilities) (*) $ (136) $ (21) $ (39) $ (9) $ (58) Balance at December 31, 2021: Regulatory assets (liabilities): Prior service cost $ 13 $ 3 $ 5 $ 1 $ 1 Net gain (87) (65) (15) — (51) Regulatory amortization — — — — 16 Total regulatory assets (liabilities) (*) $ (74) $ (62) $ (10) $ 1 $ (34) (*) Amounts for Southern Company exclude regulatory assets of $32 million and $40 million at December 31, 2022 and 2021, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company. The changes in the balance of net regulatory assets (liabilities) related to the other postretirement benefit plans for the plan years ended December 31, 2022 and 2021 are presented in the following table: Southern Company Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Net regulatory assets (liabilities): (*) Balance at December 31, 2020 $ 51 $ (21) $ 47 $ 5 $ (23) Net gain (120) (41) (55) (4) (2) Reclassification adjustments: Amortization of prior service costs 1 — 1 — — Amortization of net loss (6) — (3) — — Amortization of regulatory assets (*) — — — — (9) Total reclassification adjustments (5) — (2) — (9) Total change (125) (41) (57) (4) (11) Balance at December 31, 2021 $ (74) $ (62) $ (10) $ 1 $ (34) Net (gain) loss (64) 41 (27) (10) (13) Reclassification adjustments: Amortization of prior service costs 1 — — — — Amortization of net gain (loss) 1 — (2) — — Amortization of regulatory assets (*) — — — — (11) Total reclassification adjustments 2 — (2) — (11) Total change (62) 41 (29) (10) (24) Balance at December 31, 2022 $ (136) $ (21) $ (39) $ (9) $ (58) (*) Amounts for Southern Company exclude regulatory assets of $32 million and $40 million at December 31, 2022 and 2021, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company. Presented below are the amounts included in AOCI at December 31, 2022 and 2021 related to the other postretirement benefit plans of Southern Company, Southern Power, and Southern Company Gas that had not yet been recognized in net periodic other postretirement benefit cost. Southern Southern Southern Company (in millions) Balance at December 31, 2022 AOCI: Prior service cost $ 1 $ — $ — Net (gain) loss (5) — (2) Total AOCI $ (4) $ — $ (2) Balance at December 31, 2021 AOCI: Prior service cost $ 1 $ — $ 1 Net (gain) loss (1) 2 (6) Total AOCI $ — $ 2 $ (5) The components of OCI related to the other postretirement benefit plans for the plan years ended December 31, 2022 and 2021 are presented in the following table: Southern Company Southern Southern Company Gas (in millions) AOCI: Balance at December 31, 2020 $ 8 $ 3 $ — Net gain (11) (1) — Reclassification adjustments: Amortization of net gain (loss) 3 — (5) Total change (8) (1) (5) Balance at December 31, 2021 $ — $ 2 $ (5) Net gain (3) (2) — Reclassification adjustments: Amortization of net gain (loss) (1) — 3 Total change (4) (2) 3 Balance at December 31, 2022 $ (4) $ — $ (2) Components of the other postretirement benefit plans' net periodic cost for the Registrants were as follows: Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) 2022 Service cost $ 23 $ 6 $ 6 $ 1 $ — $ 1 Interest cost 42 10 15 2 — 5 Expected return on plan assets (80) (32) (28) (2) 1 (9) Net amortization (1) — 2 — — 6 Net periodic postretirement benefit cost (income) $ (16) $ (16) $ (5) $ 1 $ 1 $ 3 2021 Service cost $ 24 $ 6 $ 7 $ 1 $ — $ 2 Interest cost 35 9 12 1 — 4 Expected return on plan assets (76) (30) (26) (1) 1 (10) Net amortization 2 — 2 — — 6 Net periodic postretirement benefit cost (income) $ (15) $ (15) $ (5) $ 1 $ 1 $ 2 2020 Service cost $ 22 $ 6 $ 6 $ 1 $ 1 $ 2 Interest cost 54 13 20 2 — 7 Expected return on plan assets (72) (29) (26) (1) — (10) Net amortization 1 — 2 — — 6 Net periodic postretirement benefit cost (income) $ 5 $ (10) $ 2 $ 2 $ 1 $ 5 The service cost component of net periodic postretirement benefit cost is included in operations and maintenance expenses and all other components of net periodic postretirement benefit cost are included in other income (expense), net in the Registrants' statements of income. The Registrants' future benefit payments, including prescription drug benefits, are provided in the table below. These amounts reflect expected future service and are estimated based on assumptions used to measure the APBO for the other postretirement benefit plans. Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Benefit payments: 2023 $ 115 $ 25 $ 41 $ 5 $ 1 $ 18 2024 110 24 39 5 1 17 2025 114 26 41 5 1 17 2026 113 26 41 5 1 16 2027 113 26 41 5 1 16 2028 to 2032 551 130 199 22 1 68 Benefit Plan Assets Pension plan and other postretirement benefit plan assets are managed and invested in accordance with all applicable requirements, including ERISA and the Internal Revenue Code. The Registrants' investment policies for both the pension plans and the other postretirement benefit plans cover a diversified mix of assets as described below. Derivative instruments may be used to gain efficient exposure to the various asset classes and as hedging tools. Additionally, the Registrants minimize the risk of large losses primarily through diversification but also monitor and manage other aspects of risk. The investment strategy for plan assets related to the Southern Company system's qualified pension plan is to be broadly diversified across major asset classes. The asset allocation is established after consideration of various factors that affect the assets and liabilities of the pension plan including, but not limited to, historical and expected returns and interest rates, volatility, correlations of asset classes, the current level of assets and liabilities, and the assumed growth in assets and liabilities. Because a significant portion of the liability of the pension plan is long-term in nature, the assets are invested consistent with long-term investment expectations for return and risk. To manage the actual asset class exposures relative to the target asset allocation, the Southern Company system employs a formal rebalancing program. As additional risk management, external investment managers and service providers are subject to written guidelines to ensure appropriate and prudent investment practices. Management believes the portfolio is well-diversified with no significant concentrations of risk. Southern Company's investment strategy also includes adjusting the established asset allocation to invest a larger portion of the portfolio in fixed rate debt securities should the qualified pension plan achieve a predetermined funding threshold, which occurred during 2022. Investment Strategies and Benefit Plan Asset Fair Values A description of the major asset classes that the pension and other postretirement benefit plans are comprised of, along with the valuation methods used for fair value measurement, is provided below: Description Valuation Methodology Domestic equity: A mix of large and small capitalization stocks with generally an equal distribution of value and growth attributes, managed both actively and through passive index approaches. International equity: A mix of large and small capitalization growth and value stocks with developed and emerging markets exposure, managed both actively and through fundamental indexing approaches. Domestic and international equities such as common stocks, American depositary receipts, and real estate investment trusts that trade on public exchanges are classified as Level 1 investments and are valued at the closing price in the active market. Equity funds with unpublished prices that are comprised of publicly traded securities (such as commingled/pooled funds) are also valued at the closing price in the active market, but are classified as Level 2. Fixed income: A mix of domestic and international bonds. Investments in fixed income securities, including fixed income pooled funds, are generally classified as Level 2 investments and are valued based on prices reported in the market place. Additionally, the value of fixed income securities takes into consideration certain items such as broker quotes, spreads, yield curves, interest rates, and discount rates that apply to the term of a specific instrument. Trust-owned life insurance (TOLI): Investments of taxable trusts aimed at minimizing the impact of taxes on the portfolio. Investments in TOLI policies are classified as Level 2 investments and are valued based on the underlying investments held in the policy's separate accounts. The underlying assets are equity and fixed income pooled funds that are comprised of Level 1 and Level 2 securities. Real estate: Investments in traditional private market, equity-oriented investments in real properties (indirectly through pooled funds or partnerships) and in publicly traded real estate securities. Special situations: Investments in opportunistic strategies with the objective of diversifying and enhancing returns and exploiting short-term inefficiencies, as well as investments in promising new strategies of a longer-term nature. Private equity: Investments in private partnerships that invest in private or public securities typically through privately-negotiated and/or structured transactions, including leveraged buyouts, venture capital, and distressed debt. Investments in real estate, special situations, and private equity are generally classified as Net Asset Value as a Practical Expedient, since the underlying assets typically do not have publicly available observable inputs. The fund manager values the assets using various inputs and techniques depending on the nature of the underlying investments. Techniques may include purchase multiples for comparable transactions, comparable public company trading multiples, discounted cash flow analysis, prevailing market capitalization rates, recent sales of comparable investments, and independent third-party appraisals. The fair value of partnerships is determined by aggregating the value of the underlying assets less liabilities. For purposes of determining the fair value of the pension plan and other postretirement benefit plan assets and the appropriate level designation, management relies on information provided by the plan's trustee. This information is reviewed and evaluated by management with changes made to the trustee information as appropriate. The fair values presented herein exclude cash, receivables related to investment income and pending investment sales, and payables related to pending investment purchases. The fair values, and actual allocations relative to the target allocations, of the Southern Company system's pension plans at December 31, 2022 and 2021 are presented below. Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Equity: 45 % 43 % Domestic equity $ 2,078 $ 691 $ — $ — $ 2,769 International equity 2,166 1,090 — — 3,256 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 1,469 — — 1,469 Mortga

STOCK COMPENSATION

STOCK COMPENSATION	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
STOCK COMPENSATION	STOCK COMPENSATION Stock-based compensation primarily in the form of Southern Company performance share units (PSU) and restricted stock units (RSU) may be granted through the Equity and Incentive Compensation Plan to Southern Company system employees ranging from line management to executives. At December 31, 2022, the number of current and former employees participating in stock-based compensation programs for the Registrants was as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Number of employees 1,586 221 236 64 45 186 The majority of PSUs and RSUs awarded contain terms where employees become immediately vested in PSUs and RSUs upon retirement. As a result, compensation expense for employees that are retirement eligible at the grant date is recognized immediately, while compensation expense for employees that become retirement eligible during the vesting period is recognized over the period from grant date to the date of retirement eligibility. In addition, the Registrants recognize forfeitures as they occur. All unvested PSUs and RSUs vest immediately upon a change in control where Southern Company is not the surviving corporation. Performance Share Units PSUs granted to employees vest at the end of a three-year performance period. Shares of Southern Company common stock are delivered to employees at the end of the performance period with the number of shares issued ranging from 0% to 200% of the target number of PSUs granted, based on achievement of the performance goals established by the Compensation Committee of the Southern Company Board of Directors. Southern Company has issued three types of PSUs, each with a unique performance goal. These types of PSUs include total shareholder return (TSR) awards based on the TSR for Southern Company common stock during the three The fair value of TSR awards is determined as of the grant date using a Monte Carlo simulation model. In determining the fair value of the TSR awards issued to employees, the expected volatility is based on the historical volatility of Southern Company's stock over a period equal to the performance period. The risk-free rate is based on the U.S. Treasury yield curve in effect at the time of grant that covers the performance period of the awards. The following table shows the assumptions used in the pricing model and the weighted average grant-date fair value of TSR awards granted: Year Ended December 31 2022 2021 2020 Expected volatility 29.6% 30.0% 15.4% Expected term (in years) 3 3 3 Interest rate 1.7% 0.2% 1.4% Weighted average grant-date fair value $79.69 $69.06 $77.65 The Registrants recognize TSR award compensation expense on a straight-line basis over the three-year performance period without remeasurement. The fair values of EPS awards and ROE awards are based on the closing stock price of Southern Company common stock on the date of the grant. The weighted average grant-date fair value of the ROE awards granted during 2022, 2021, and 2020 was $66.87, $59.49, and $68.42, respectively. Compensation expense for EPS and ROE awards is generally recognized ratably over the three-year performance period adjusted for expected changes in EPS and ROE performance. Total compensation cost recognized for vested EPS awards and ROE awards reflects final performance metrics. Southern Company had 2.2 million unvested PSUs outstanding at December 31, 2021. In February 2022, the PSUs that vested for the three-year performance period ended December 31, 2021 were converted into 2.5 million shares outstanding at a share price of $66.57. During 2022, Southern Company granted 1.3 million PSUs and 1.1 million PSUs were vested or forfeited, resulting in 2.4 million unvested PSUs outstanding at December 31, 2022. In February 2023, the PSUs that vested for the three-year performance period ended December 31, 2022 were converted into 1.8 million shares outstanding at a weighted average share price of $67.13. Total PSU compensation cost, and the related tax benefit recognized in income, for the years ended December 31, 2022, 2021, and 2020 are as follows: 2022 2021 2020 (in millions) Southern Company Compensation cost recognized in income $ 101 $ 112 $ 84 Tax benefit of compensation cost recognized in income 26 29 22 Southern Company Gas Compensation cost recognized in income $ 12 $ 17 $ 13 Tax benefit of compensation cost recognized in income 4 4 4 Total PSU compensation cost and the related tax benefit recognized in income were immaterial for all periods presented for all other Registrants. The compensation cost related to the grant of Southern Company PSUs to the employees of each Subsidiary Registrant is recognized in each Subsidiary Registrant's financial statements with a corresponding credit to equity representing a capital contribution from Southern Company. At December 31, 2022, Southern Company's total unrecognized compensation cost related to PSUs was $31 million and is expected to be recognized over a weighted-average period of approximately 19 months. The total unrecognized compensation cost related to PSUs at December 31, 2022 was immaterial for all other Registrants. Restricted Stock Units The fair value of RSUs is based on the closing stock price of Southern Company common stock on the date of the grant. The weighted average grant-date fair values of RSUs granted during 2022, 2021, and 2020 were $67.20, $59.56, and $67.60, respectively. For most RSU awards, one-third of the RSUs vest each year throughout a three-year service period and compensation cost for RSUs is generally recognized over the corresponding one two Southern Company had 1.1 million RSUs outstanding at December 31, 2021. During 2022, Southern Company granted 0.4 million RSUs and 0.6 million RSUs were vested or forfeited, resulting in 0.9 million unvested RSUs outstanding at December 31, 2022, including RSUs related to employee retention agreements. For the years ended December 31, 2022, 2021, and 2020, Southern Company's total compensation cost for RSUs recognized in income was $26 million, $32 million, and $29 million, respectively. The related tax benefit also recognized in income was $7 million, $8 million, and $8 million for the years ended December 31, 2022, 2021, and 2020, respectively. Total unrecognized compensation cost related to RSUs at December 31, 2022, which is being recognized over a weighted-average period of approximately 18 months, is immaterial for Southern Company. Total RSUs outstanding and total compensation cost and related tax benefit for the RSUs recognized in income for the years ended December 31, 2022, 2021, and 2020, as well as the total unrecognized compensation cost at December 31, 2022, were immaterial for all other Registrants. The compensation cost related to the grant of Southern Company RSUs to the employees of each Subsidiary Registrant is recognized in such Subsidiary Registrant's financial statements with a corresponding credit to equity representing a capital contribution from Southern Company. Stock Options In 2015, Southern Company discontinued granting stock options. As of December 31, 2017, all stock option awards were vested and compensation cost fully recognized. Stock options expire no later than 10 years after the grant date and the latest possible exercise will occur by November 2024. At December 31, 2022, the weighted average remaining contractual term for the options outstanding and exercisable was approximately 10 months. Southern Company's activity in the stock option program for 2022 is summarized below: Shares Subject to Option Weighted Average Exercise Price (in millions) Outstanding at December 31, 2021 2.8 $ 42.95 Exercised 1.8 43.37 Outstanding and Exercisable at December 31, 2022 1.0 $ 42.22 Southern Company's cash receipts from issuances related to stock options exercised under the share-based payment arrangements for the years ended December 31, 2022, 2021, and 2020 were $75 million, $66 million, and $66 million, respectively. At December 31, 2022, the aggregate intrinsic value for options outstanding and exercisable was $29 million for Southern Company and immaterial for all other Registrants. Total intrinsic value of options exercised, and the related tax benefit, for the years ended December 31, 2022, 2021, and 2020 are presented below for Southern Company and Georgia Power and were immaterial for all other Registrants: Year Ended December 31 2022 2021 2020 (in millions) Southern Company Intrinsic value of options exercised $ 49 $ 34 $ 38 Tax benefit of options exercised 12 7 9 Georgia Power Intrinsic value of options exercised $ 15 $ 14 $ 9 Tax benefit of options exercised 4 3 2

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Fair value measurements are based on inputs of observable and unobservable market data that a market participant would use in pricing the asset or liability. The use of observable inputs is maximized where available and the use of unobservable inputs is minimized for fair value measurement and reflects a three-tier fair value hierarchy that prioritizes inputs to valuation techniques used for fair value measurement. • Level 1 consists of observable market data in an active market for identical assets or liabilities. • Level 2 consists of observable market data, other than that included in Level 1, that is either directly or indirectly observable. • Level 3 consists of unobservable market data. The input may reflect the assumptions of each Registrant of what a market participant would use in pricing an asset or liability. If there is little available market data, then each Registrant's own assumptions are the best available information. In the case of multiple inputs being used in a fair value measurement, the lowest level input that is significant to the fair value measurement represents the level in the fair value hierarchy in which the fair value measurement is reported. Net asset value as a practical expedient is the classification used for assets that do not have readily determined fair values. Fund managers value the assets using various inputs and techniques depending on the nature of the underlying investments. At December 31, 2022, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 18 $ 181 $ — $ — $ 199 Interest rate derivatives — 12 — — 12 Investments in trusts: (b)(c) Domestic equity 651 178 — — 829 Foreign equity 125 150 — — 275 U.S. Treasury and government agency securities — 285 — — 285 Municipal bonds — 51 — — 51 Pooled funds – fixed income — 7 — — 7 Corporate bonds — 412 — — 412 Mortgage and asset backed securities — 90 — — 90 Private equity — — — 161 161 Cash and cash equivalents 4 — — — 4 Other 37 12 — — 49 Cash equivalents 1,427 20 — — 1,447 Other investments 9 26 — — 35 Total $ 2,271 $ 1,424 $ — $ 161 $ 3,856 Liabilities: Energy-related derivatives (a) $ 32 $ 178 $ — $ — $ 210 Interest rate derivatives — 302 — — 302 Foreign currency derivatives — 216 — — 216 Contingent consideration — — 12 — 12 Other — 13 — — 13 Total $ 32 $ 709 $ 12 $ — $ 753 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 62 $ — $ — $ 62 Nuclear decommissioning trusts: (b) Domestic equity 396 169 — — 565 Foreign equity 125 — — — 125 U.S. Treasury and government agency securities — 19 — — 19 Municipal bonds — 1 — — 1 Corporate bonds — 225 — — 225 Mortgage and asset backed securities — 22 — — 22 Private equity — — — 161 161 Other 7 — — — 7 Cash equivalents 438 20 — — 458 Other investments — 26 — — 26 Total $ 966 $ 544 $ — $ 161 $ 1,671 Liabilities: Energy-related derivatives $ — $ 39 $ — $ — $ 39 Georgia Power Assets: Energy-related derivatives $ — $ 42 $ — $ — $ 42 Nuclear decommissioning trusts: (b)(c) Domestic equity 255 1 — — 256 Foreign equity — 149 — — 149 U.S. Treasury and government agency securities — 266 — — 266 Municipal bonds — 50 — — 50 Corporate bonds — 187 — — 187 Mortgage and asset backed securities — 68 — — 68 Other 30 12 — — 42 Cash equivalents 355 — — — 355 Total $ 640 $ 775 $ — $ — $ 1,415 Liabilities: Energy-related derivatives $ — $ 62 $ — $ — $ 62 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 59 $ — $ — $ 59 Cash equivalents 47 — — — 47 Total $ 47 $ 59 $ — $ — $ 106 Liabilities: Energy-related derivatives $ — $ 32 $ — $ — $ 32 Southern Power Assets: Energy-related derivatives $ — $ 8 $ — $ — $ 8 Liabilities: Energy-related derivatives $ — $ 12 $ — $ — $ 12 Foreign currency derivatives — 47 — — 47 Contingent consideration — — 12 — 12 Other — 13 — — 13 Total $ — $ 72 $ 12 $ — $ 84 Southern Company Gas Assets: Energy-related derivatives (a) $ 18 $ 10 $ — $ — $ 28 Non-qualified deferred compensation trusts: Domestic equity — 8 — — 8 Foreign equity — 1 — — 1 Pooled funds - fixed income — 7 — — 7 Cash and cash equivalents 4 — — — 4 Cash equivalents 50 — — — 50 Total $ 72 $ 26 $ — $ — $ 98 Liabilities: Energy-related derivatives (a)(b) $ 32 $ 33 $ — $ — $ 65 Interest rate derivatives — 86 — — 86 Total $ 32 $ 119 $ — $ — $ 151 (a) Excludes cash collateral of $41 million. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information. (c) Includes investment securities pledged to creditors and collateral received and excludes payables related to the securities lending program. See Note 6 under "Nuclear Decommissioning" for additional information. At December 31, 2021, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2021: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 24 $ 195 $ — $ — $ 219 Interest rate derivatives — 19 — — 19 Investments in trusts: (b)(c) Domestic equity 791 225 — — 1,016 Foreign equity 165 188 — — 353 U.S. Treasury and government agency securities — 314 — — 314 Municipal bonds — 56 — — 56 Pooled funds – fixed income — 13 — — 13 Corporate bonds 1 522 — — 523 Mortgage and asset backed securities — 93 — — 93 Private equity — — — 150 150 Cash and cash equivalents 2 — — — 2 Other 22 25 — — 47 Cash equivalents 1,160 14 — — 1,174 Other investments 9 35 — — 44 Total $ 2,174 $ 1,699 $ — $ 150 $ 4,023 Liabilities: Energy-related derivatives (a) $ 10 $ 36 $ — $ — $ 46 Interest rate derivatives — 29 — — 29 Foreign currency derivatives — 79 — — 79 Contingent consideration — — 14 — 14 Other — 13 — — 13 Total $ 10 $ 157 $ 14 $ — $ 181 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2021: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 55 $ — $ — $ 55 Nuclear decommissioning trusts: (b) Domestic equity 468 216 — — 684 Foreign equity 165 — — — 165 U.S. Treasury and government agency securities — 21 — — 21 Municipal bonds — 1 — — 1 Corporate bonds 1 271 — — 272 Mortgage and asset backed securities — 22 — — 22 Private equity — — — 150 150 Other 9 — — — 9 Cash equivalents 839 14 — — 853 Other investments — 35 — — 35 Total $ 1,482 $ 635 $ — $ 150 $ 2,267 Liabilities: Energy-related derivatives $ — $ 11 $ — $ — $ 11 Georgia Power Assets: Energy-related derivatives $ — $ 75 $ — $ — $ 75 Nuclear decommissioning trusts: (b)(c) Domestic equity 323 1 — — 324 Foreign equity — 185 — — 185 U.S. Treasury and government agency securities — 293 — — 293 Municipal bonds — 55 — — 55 Corporate bonds — 251 — — 251 Mortgage and asset backed securities — 71 — — 71 Other 13 25 — — 38 Total $ 336 $ 956 $ — $ — $ 1,292 Liabilities: Energy-related derivatives $ — $ 8 $ — $ — $ 8 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2021: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 56 $ — $ — $ 56 Cash equivalents 40 — — — 40 Total $ 40 $ 56 $ — $ — $ 96 Liabilities: Energy-related derivatives $ — $ 5 $ — $ — $ 5 Southern Power Assets: Energy-related derivatives $ — $ 4 $ — $ — $ 4 Liabilities: Foreign currency derivatives $ — $ 16 $ — $ — $ 16 Contingent consideration — — 14 — 14 Other — 13 — — 13 Total $ — $ 29 $ 14 $ — $ 43 Southern Company Gas Assets: Energy-related derivatives (a) $ 24 $ 5 $ — $ — $ 29 Interest rate derivatives — 6 — — 6 Non-qualified deferred compensation trusts: Domestic equity — 8 — — 8 Foreign equity — 3 — — 3 Pooled funds - fixed income — 13 — — 13 Cash equivalents 2 — — — 2 Total $ 26 $ 35 $ — $ — $ 61 Liabilities: Energy-related derivatives (a)(b) $ 10 $ 12 $ — $ — $ 22 Interest rate derivatives — 5 — — 5 Total $ 10 $ 17 $ — $ — $ 27 (a) Excludes immaterial cash collateral. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information. (c) Includes investment securities pledged to creditors and collateral received and excludes payables related to the securities lending program. See Note 6 under "Nuclear Decommissioning" for additional information. Valuation Methodologies The energy-related derivatives primarily consist of exchange-traded and over-the-counter financial products for natural gas and physical power products, including, from time to time, basis swaps. These are standard products used within the energy industry and are valued using the market approach. The inputs used are mainly from observable market sources, such as forward natural gas prices, power prices, implied volatility, and overnight index swap interest rates. Interest rate derivatives are also standard over-the-counter products that are valued using observable market data and assumptions commonly used by market participants. The fair value of interest rate derivatives reflects the net present value of expected payments and receipts under the swap agreement based on the market's expectation of future interest rates. Additional inputs to the net present value calculation may include the contract terms, counterparty credit risk, and occasionally, implied volatility of interest rate options. The fair value of cross-currency swaps reflects the net present value of expected payments and receipts under the swap agreement based on the market's expectation of future foreign currency exchange rates. Additional inputs to the net present value calculation may include the contract terms, counterparty credit risk, and discount rates. The interest rate derivatives and cross-currency swaps are categorized as Level 2 under Fair Value Measurements as these inputs are based on observable data and valuations of similar instruments. See Note 14 for additional information on how these derivatives are used. For fair value measurements of the investments within the nuclear decommissioning trusts and the non-qualified deferred compensation trusts, external pricing vendors are designated for each asset class with each security specifically assigned a primary pricing source. For investments held within commingled funds, fair value is determined at the end of each business day through the net asset value, which is established by obtaining the underlying securities' individual prices from the primary pricing source. A market price secured from the primary source vendor is then evaluated by management in its valuation of the assets within the trusts. As a general approach, fixed income market pricing vendors gather market data (including indices and market research reports) and integrate relative credit information, observed market movements, and sector news into proprietary pricing models, pricing systems, and mathematical tools. Dealer quotes and other market information, including live trading levels and pricing analysts' judgments, are also obtained when available. The NRC requires licensees of commissioned nuclear power reactors to establish a plan for providing reasonable assurance of funds for future decommissioning. See Note 6 under "Nuclear Decommissioning" for additional information. Southern Power has contingent payment obligations related to certain acquisitions whereby it is primarily obligated to make generation-based payments to the seller, which commenced at the commercial operation of the respective facility and continue through 2026. The obligations are categorized as Level 3 under Fair Value Measurements as the fair value is determined using significant unobservable inputs for the forecasted facility generation in MW-hours, as well as other inputs such as a fixed dollar amount per MW-hour, and a discount rate. The fair value of contingent consideration reflects the net present value of expected payments and any periodic change arising from forecasted generation is expected to be immaterial. Southern Power also has payment obligations through 2040 whereby it must reimburse the transmission owners for interconnection facilities and network upgrades constructed to support connection of a Southern Power generating facility to the transmission system. The obligations are categorized as Level 2 under Fair Value Measurements as the fair value is determined using observable inputs for the contracted amounts and reimbursement period, as well as a discount rate. The fair value of the obligations reflects the net present value of expected payments. "Other investments" include investments traded in the open market that have maturities greater than 90 days, which are categorized as Level 2 under Fair Value Measurements and are comprised of corporate bonds, bank certificates of deposit, treasury bonds, and/or agency bonds. The fair value measurements of private equity investments held in Alabama Power's nuclear decommissioning trusts that are calculated at net asset value per share (or its equivalent) as a practical expedient totaled $161 million and $150 million at December 31, 2022 and 2021, respectively. Unfunded commitments related to the private equity investments totaled $78 million and $69 million at December 31, 2022 and 2021, respectively. Private equity investments include high-quality private equity funds across several market sectors and funds that invest in real estate assets. Private equity funds do not have redemption rights. Distributions from these funds will be received as the underlying investments in the funds are liquidated. At December 31, 2022 and 2021, other financial instruments for which the carrying amount did not equal fair value were as follows: Southern Company (*) Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (*) (in billions) At December 31, 2022: Long-term debt, including securities due within one year: Carrying amount $ 54.6 $ 10.6 $ 14.7 $ 1.5 $ 3.0 $ 7.4 Fair value 48.6 9.2 13.0 1.3 2.8 6.5 At December 31, 2021: Long-term debt, including securities due within one year: Carrying amount $ 52.1 $ 9.7 $ 13.6 $ 1.5 $ 3.7 $ 6.9 Fair value 57.1 10.9 15.1 1.6 4.1 7.8 (*) The long-term debt of Southern Company Gas is recorded at amortized cost, including the fair value adjustments at the effective date of the 2016 merger with Southern Company. Southern Company Gas amortizes the fair value adjustments over the remaining lives of the respective bonds, the latest being through 2043. The fair values are determined using Level 2 measurements and are based on quoted market prices for the same or similar issues or on the current rates available to the Registrants.

DERIVATIVES

DERIVATIVES	12 Months Ended
	Dec. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVES	DERIVATIVES The Registrants are exposed to market risks, including commodity price risk, interest rate risk, weather risk, and occasionally foreign currency exchange rate risk. To manage the volatility attributable to these exposures, each company nets its exposures, where possible, to take advantage of natural offsets and enters into various derivative transactions for the remaining exposures pursuant to each company's policies in areas such as counterparty exposure and risk management practices. Prior to the sale of Sequent on July 1, 2021, Southern Company Gas' wholesale gas operations used various contracts in its commercial activities that generally met the definition of derivatives. For the traditional electric operating companies, Southern Power, and Southern Company Gas' other businesses, each company's policy is that derivatives are to be used primarily for hedging purposes and mandates strict adherence to all applicable risk management policies. Derivative positions are monitored using techniques including, but not limited to, market valuation, value at risk, stress testing, and sensitivity analysis. Derivative instruments are recognized at fair value in the balance sheets as either assets or liabilities and are presented on a net basis. See Note 13 for additional fair value information. In the statements of cash flows, any cash impacts of settled energy-related and interest rate derivatives are recorded as operating activities. Any cash impacts of settled foreign currency derivatives are classified as operating or financing activities to correspond with the classification of the hedged interest or principal, respectively. See Note 1 under "Financial Instruments" for additional information. See Note 15 under "Southern Company Gas" for additional information regarding the sale of Sequent. Energy-Related Derivatives The Subsidiary Registrants enter into energy-related derivatives to hedge exposures to electricity, natural gas, and other fuel price changes. However, due to cost-based rate regulations and other various cost recovery mechanisms, the traditional electric operating companies and the natural gas distribution utilities have limited exposure to market volatility in energy-related commodity prices. Each of the traditional electric operating companies and certain of the natural gas distribution utilities of Southern Company Gas manage fuel-hedging programs, implemented per the guidelines of their respective state PSCs or other applicable state regulatory agencies, through the use of financial derivative contracts, which are expected to continue to mitigate price volatility. The traditional electric operating companies (with respect to wholesale generating capacity) and Southern Power have limited exposure to market volatility in energy-related commodity prices because their long-term sales contracts shift substantially all fuel cost responsibility to the purchaser. However, the traditional electric operating companies and Southern Power may be exposed to market volatility in energy-related commodity prices to the extent any uncontracted capacity is used to sell electricity. Southern Company Gas retains exposure to price changes that can, in a volatile energy market, be material and can adversely affect its results of operations. Southern Company Gas also enters into weather derivative contracts as economic hedges in the event of warmer-than-normal weather. Exchange-traded options are carried at fair value, with changes reflected in operating revenues. Non-exchange-traded options are accounted for using the intrinsic value method. Changes in the intrinsic value for non-exchange-traded contracts are reflected in operating revenues. Energy-related derivative contracts are accounted for under one of three methods: • Regulatory Hedges – Energy-related derivative contracts designated as regulatory hedges relate primarily to the traditional electric operating companies' and the natural gas distribution utilities' fuel-hedging programs, where gains and losses are initially recorded as regulatory liabilities and assets, respectively, and then are included in fuel expense as the underlying fuel is used in operations and ultimately recovered through an approved cost recovery mechanism. • Cash Flow Hedges – Gains and losses on energy-related derivatives designated as cash flow hedges (which are mainly used to hedge anticipated purchases and sales) are initially deferred in AOCI before being recognized in the statements of income in the same period and in the same income statement line item as the earnings effect of the hedged transactions. • Not Designated – Gains and losses on energy-related derivative contracts that are not designated or fail to qualify as hedges are recognized in the statements of income as incurred. Some energy-related derivative contracts require physical delivery as opposed to financial settlement, and this type of derivative is both common and prevalent within the electric and natural gas industries. When an energy-related derivative contract is settled physically, any cumulative unrealized gain or loss is reversed and the contract price is recognized in the respective line item representing the actual price of the underlying goods being delivered. At December 31, 2022, the net volume of energy-related derivative contracts for natural gas positions, together with the longest hedge date over which the respective entity is hedging its exposure to the variability in future cash flows for forecasted transactions and the longest non-hedge date for derivatives not designated as hedges, were as follows: Net Longest Longest (in millions) Southern Company (*) 431 2030 2025 Alabama Power 111 2026 — Georgia Power 125 2026 — Mississippi Power 94 2027 — Southern Power 8 2030 2023 Southern Company Gas (*) 93 2025 2025 (*) Southern Company Gas' derivative instruments include both long and short natural gas positions. A long position is a contract to purchase natural gas and a short position is a contract to sell natural gas. Southern Company Gas' volume represents the net of long natural gas positions of 98 million mmBtu and short natural gas positions of 5 million mmBtu at December 31, 2022, which is also included in Southern Company's total volume. See Note 15 under "Southern Company Gas" for information regarding the sale of Sequent. In addition to the volumes discussed above, the traditional electric operating companies and Southern Power enter into physical natural gas supply contracts that provide the option to sell back excess natural gas due to operational constraints. The maximum expected volume of natural gas subject to such a feature is 23 million mmBtu for Southern Company, which includes 6 million mmBtu for Alabama Power, 8 million mmBtu for Georgia Power, 3 million mmBtu for Mississippi Power, and 6 million mmBtu for Southern Power. For cash flow hedges of energy-related derivatives, the estimated pre-tax gains (losses) expected to be reclassified from AOCI to earnings for the year ending December 31, 2023 are $(27) million for Southern Company, $(11) million for Southern Power, and $(16) million for Southern Company Gas. Interest Rate Derivatives Southern Company and certain subsidiaries may enter into interest rate derivatives to hedge exposure to changes in interest rates. Derivatives related to existing variable rate securities or forecasted transactions are accounted for as cash flow hedges where the derivatives' fair value gains or losses are recorded in OCI and are reclassified into earnings at the same time and presented on the same income statement line item as the earnings effect of the hedged transactions. Derivatives related to existing fixed rate securities are accounted for as fair value hedges, where the derivatives' fair value gains or losses and hedged items' fair value gains or losses are both recorded directly to earnings on the same income statement line item. Fair value gains or losses on derivatives that are not designated or fail to qualify as hedges are recognized in the statements of income as incurred. At December 31, 2022, the following interest rate derivatives were outstanding: Notional Weighted Average Interest Rate Paid Interest Hedge Fair Value (in millions) (in millions) Cash Flow Hedges of Forecasted Debt Southern Company parent $ 400 3.50% N/A June 2033 $ 12 Fair Value Hedges of Existing Debt Southern Company parent 400 1-month LIBOR + 0.68% 1.75% March 2028 (55) Southern Company parent 1,000 1-month LIBOR + 2.36% 3.70% April 2030 (161) Southern Company Gas 500 1-month LIBOR + 0.38% 1.75% January 2031 (86) Southern Company $ 2,300 $ (290) For cash flow hedges of interest rate derivatives, the estimated pre-tax gains (losses) expected to be reclassified from AOCI to interest expense for the year ending December 31, 2023 are $(16) million for Southern Company and immaterial for the other Registrants. Deferred gains and losses related to interest rate derivatives are expected to be amortized into earnings through 2052 for Southern Company, Alabama Power, and Georgia Power, 2028 for Mississippi Power, and 2046 for Southern Company Gas. Foreign Currency Derivatives Southern Company and certain subsidiaries, including Southern Power, may enter into foreign currency derivatives to hedge exposure to changes in foreign currency exchange rates, such as that arising from the issuance of debt denominated in a currency other than U.S. dollars. Derivatives related to forecasted transactions are accounted for as cash flow hedges where the derivatives' fair value gains or losses are recorded in OCI and are reclassified into earnings at the same time and on the same income statement line as the earnings effect of the hedged transactions, including foreign currency gains or losses arising from changes in the U.S. currency exchange rates. Derivatives related to existing fixed rate securities are accounted for as fair value hedges, where the derivatives' fair value gains or losses and hedged items' fair value gains or losses are both recorded directly to earnings on the same income statement line item, including foreign currency gains or losses arising from changes in the U.S. currency exchange rates. Southern Company has elected to exclude the cross-currency basis spread from the assessment of effectiveness in the fair value hedges of its foreign currency risk and record any difference between the change in the fair value of the excluded components and the amounts recognized in earnings as a component of OCI. At December 31, 2022, the following foreign currency derivatives were outstanding: Pay Notional Pay Rate Receive Notional Receive Rate Hedge Fair Value (in millions) (in millions) (in millions) Cash Flow Hedges of Existing Debt Southern Power $ 564 3.78% € 500 1.85% June 2026 $ (47) Fair Value Hedges of Existing Debt Southern Company parent 1,476 3.39% 1,250 1.88% September 2027 (169) Southern Company $ 2,040 € 1,750 $ (216) For cash flow hedges of foreign currency derivatives, the estimated pre-tax losses expected to be reclassified from AOCI to earnings for the year ending December 31, 2023 are $11 million for Southern Power. Derivative Financial Statement Presentation and Amounts The Registrants enter into derivative contracts that may contain certain provisions that permit intra-contract netting of derivative receivables and payables for routine billing and offsets related to events of default and settlements. Southern Company and certain subsidiaries also utilize master netting agreements to mitigate exposure to counterparty credit risk. These agreements may contain provisions that permit netting across product lines and against cash collateral. The fair value amounts of derivative assets and liabilities on the balance sheets are presented net to the extent that there are netting arrangements or similar agreements with the counterparties. At December 31, 2022 and 2021, the fair value of energy-related derivatives, interest rate derivatives, and foreign currency derivatives was reflected in the balance sheets as follows: 2022 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) Southern Company Energy-related derivatives designated as hedging instruments for regulatory purposes Assets from risk management activities/Other current liabilities $ 123 $ 121 $ 129 $ 30 Other deferred charges and assets/Other deferred credits and liabilities 52 44 72 6 Total derivatives designated as hedging instruments for regulatory purposes 175 165 201 36 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Assets from risk management activities/Other current liabilities 3 27 7 5 Other deferred charges and assets/Other deferred credits and liabilities 6 4 1 — Interest rate derivatives: Assets from risk management activities/Other current liabilities 12 62 19 — Other deferred charges and assets/Other deferred credits and liabilities — 240 — 29 Foreign currency derivatives: Assets from risk management activities/Other current liabilities — 34 — 39 Other deferred charges and assets/Other deferred credits and liabilities — 182 — 40 Total derivatives designated as hedging instruments in cash flow and fair value hedges 21 549 27 113 Energy-related derivatives not designated as hedging instruments Assets from risk management activities/Other current liabilities 13 13 9 4 Other deferred charges and assets/Other deferred credits and liabilities 2 1 1 — Total derivatives not designated as hedging instruments 15 14 10 4 Gross amounts recognized 211 728 238 153 Gross amounts offset (a) (70) (111) (25) (28) Net amounts recognized in the Balance Sheets (b) $ 141 $ 617 $ 213 $ 125 2022 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) Alabama Power (c) Energy-related derivatives designated as hedging instruments for regulatory purposes Other current assets/Other current liabilities $ 42 $ 21 $ 30 $ 9 Other deferred charges and assets/Other deferred credits and liabilities 20 18 25 2 Total derivatives designated as hedging instruments for regulatory purposes 62 39 55 11 Gross amounts offset (24) (24) (5) (5) Net amounts recognized in the Balance Sheets $ 38 $ 15 $ 50 $ 6 Georgia Power Energy-related derivatives designated as hedging instruments for regulatory purposes Assets from risk management activities/Other current liabilities $ 36 $ 43 $ 54 $ 6 Other deferred charges and assets/Other deferred credits and liabilities 6 18 21 2 Total derivatives designated as hedging instruments for regulatory purposes 42 61 75 8 Energy-related derivatives not designated as hedging instruments Other deferred charges and assets/Other deferred credits and liabilities — 1 — — Gross amounts recognized 42 62 75 8 Gross amounts offset (21) (21) (8) (8) Net amounts recognized in the Balance Sheets $ 21 $ 41 $ 67 $ — Mississippi Power (c) Energy-related derivatives designated as hedging instruments for regulatory purposes Assets from risk management activities/Other current liabilities $ 33 $ 24 $ 30 $ 3 Other deferred charges and assets/Other deferred credits and liabilities 26 8 26 2 Total derivatives designated as hedging instruments for regulatory purposes 59 32 56 5 Gross amounts offset (17) (17) (4) (4) Net amounts recognized in the Balance Sheets $ 42 $ 15 $ 52 $ 1 2022 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) Southern Power Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Other current assets/Other current liabilities $ — $ 12 $ 2 $ — Other deferred charges and assets/Other deferred credits and liabilities 5 — 1 — Foreign currency derivatives: Other current assets/Other current liabilities — 11 — 16 Other deferred charges and assets/Other deferred credits and liabilities — 36 — — Total derivatives designated as hedging instruments in cash flow and fair value hedges 5 59 3 16 Energy-related derivatives not designated as hedging instruments Other current assets/Other current liabilities 2 — 1 — Other deferred charges and assets/Other deferred credits and liabilities 1 — — — Total derivatives not designated as hedging instruments 3 — 1 — Net amounts recognized in the Balance Sheets $ 8 $ 59 $ 4 $ 16 Southern Company Gas Energy-related derivatives designated as hedging instruments for regulatory purposes Other current assets/Other current liabilities $ 12 $ 33 $ 15 $ 12 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Other current assets/Other current liabilities 3 15 5 5 Other deferred charges and assets/Other deferred credits and liabilities 1 4 — — Interest rate derivatives: Other current assets/Other current liabilities — 14 6 — Other deferred charges and assets/Other deferred credits and liabilities — 72 — 6 Total derivatives designated as hedging instruments in cash flow and fair value hedges 4 105 11 11 Energy-related derivatives not designated as hedging instruments Other current assets/Other current liabilities 11 12 8 4 Other deferred charges and assets/Other deferred credits and liabilities 1 1 1 — Total derivatives not designated as hedging instruments 12 13 9 4 Gross amounts recognized 28 151 35 27 Gross amounts offset (a) — (41) (8) (11) Net amounts recognized in the Balance Sheets (b) $ 28 $ 110 $ 27 $ 16 (a) Gross amounts offset includes cash collateral held on deposit in broker margin accounts of $41 million and $3 million at December 31, 2022 and 2021, respectively. (b) Net amounts of derivative instruments outstanding exclude immaterial premium and intrinsic value associated with weather derivatives for all periods presented. (c) Energy-related derivatives not designated as hedging instruments were immaterial at December 31, 2022 and there were no such instruments at December 31, 2021. At December 31, 2022 and 2021, the pre-tax effects of unrealized derivative gains (losses) arising from energy-related derivative instruments designated as regulatory hedging instruments and deferred were as follows: Regulatory Hedge Unrealized Gain (Loss) Recognized in the Balance Sheets Derivative Category and Balance Sheet Southern Alabama Georgia Mississippi Southern Company Gas (in millions) At December 31, 2022: Energy-related derivatives: Other regulatory assets, current $ (71) $ (8) $ (26) $ (13) $ (24) Other regulatory assets, deferred (23) (7) (14) (2) — Other regulatory liabilities, current 72 29 19 22 2 Other regulatory liabilities, deferred 31 9 2 20 — Total energy-related derivative gains (losses) $ 9 $ 23 $ (19) $ 27 $ (22) At December 31, 2021: Energy-related derivatives: Other regulatory assets, current $ (17) $ (6) $ — $ — $ (11) Other regulatory liabilities, current 107 28 48 27 4 Other regulatory liabilities, deferred 65 22 19 24 — Total energy-related derivative gains (losses) $ 155 $ 44 $ 67 $ 51 $ (7) For the years ended December 31, 2022, 2021, and 2020, the pre-tax effects of cash flow and fair value hedge accounting on AOCI for the applicable Registrants were as follows: Gain (Loss) From Derivatives Recognized in OCI 2022 2021 2020 (in millions) Southern Company Cash flow hedges: Energy-related derivatives $ 3 $ 34 $ (8) Interest rate derivatives 46 5 (26) Foreign currency derivatives (105) (103) 48 Fair value hedges (*) : Foreign currency derivatives (24) (3) — Total $ (80) $ (67) $ 14 Georgia Power Interest rate derivatives $ 31 $ — $ (3) Southern Power Cash flow hedges: Energy-related derivatives $ (15) $ 12 $ (2) Foreign currency derivatives (105) (103) 48 Total $ (120) $ (91) $ 46 Southern Company Gas Cash flow hedges: Energy-related derivatives $ 18 $ 22 $ (6) Interest rate derivatives — — (23) Total $ 18 $ 22 $ (29) (*) Represents amounts excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI. The pre-tax effects of interest rate derivatives designated as cash flow hedging instruments on AOCI were immaterial for the other Registrants for all years presented. The pre-tax effects of cash flow and fair value hedge accounting on income for the years ended December 31, 2022, 2021, and 2020 were as follows: Location and Amount of Gain (Loss) Recognized in Income on Cash Flow and Fair Value Hedging Relationships 2022 2021 2020 (in millions) Southern Company Total cost of natural gas $ 3,004 $ 1,619 $ 972 Gain (loss) on energy-related cash flow hedges (a) 37 17 (8) Total depreciation and amortization 3,663 3,565 3,518 Gain (loss) on energy-related cash flow hedges (a) (5) 9 (3) Total interest expense, net of amounts capitalized (2,022) (1,837) (1,821) Gain (loss) on interest rate cash flow hedges (a) (25) (27) (26) Gain (loss) on foreign currency cash flow hedges (a) (19) (24) (23) Gain (loss) on interest rate fair value hedges (b) (291) (30) 27 Total other income (expense), net 500 456 336 Gain (loss) on foreign currency cash flow hedges (a)(c) (83) (104) 114 Gain (loss) on foreign currency fair value hedges (106) (63) — Amount excluded from effectiveness testing recognized in earnings 24 3 — Southern Power Total depreciation and amortization $ 516 $ 517 $ 494 Gain (loss) on energy-related cash flow hedges (a) (5) 9 (3) Total interest expense, net of amounts capitalized (138) (147) (151) Gain (loss) on foreign currency cash flow hedges (a) (19) (24) (23) Total other income (expense), net 7 10 19 Gain (loss) on foreign currency cash flow hedges (a)(c) (83) (104) 114 Southern Company Gas Total cost of natural gas $ 3,004 $ 1,619 $ 972 Gain (loss) on energy-related cash flow hedges (a) 37 17 (8) Total interest expense, net of amounts capitalized (263) (238) (231) Gain (loss) on interest rate cash flow hedges (a) (4) — — Gain (loss) on interest rate fair value hedges (b) (86) — — (a) Reclassified from AOCI into earnings. (b) For fair value hedges, changes in the fair value of the derivative contracts are generally equal to changes in the fair value of the underlying debt and have no material impact on income. (c) The reclassification from AOCI into other income (expense), net completely offsets currency gains and losses arising from changes in the U.S. currency exchange rates used to record the euro-denominated notes. The pre-tax effects of cash flow and fair value hedge accounting on income for interest rate derivatives and energy-related derivatives were immaterial for the traditional electric operating companies for all years presented. At December 31, 2022 and 2021, the following amounts were recorded on the balance sheets related to cumulative basis adjustments for fair value hedges: Carrying Amount of Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item Balance Sheet Location of Hedged Items At December 31, 2022 At December 31, 2021 At December 31, 2022 At December 31, 2021 (in millions) (in millions) Southern Company Long-term debt $ (2,927) $ (3,280) $ 282 $ 9 Southern Company Gas Long-term debt $ (415) $ (493) $ 81 $ 2 The pre-tax effects of energy-related derivatives not designated as hedging instruments on the statements of income of Southern Company and Southern Company Gas for the years ended December 31, 2022, 2021, and 2020 were as follows: Gain (Loss) Derivatives in Non-Designated Hedging Relationships Statements of Income Location 2022 2021 2020 (in millions) Energy-related derivatives Natural gas revenues (*) $ (11) $ (117) $ 134 Cost of natural gas (65) (27) 15 Total derivatives in non-designated hedging relationships $ (76) $ (144) $ 149 (*) Excludes the impact of weather derivatives recorded in natural gas revenues of $(7) million and $9 million for 2022 and 2020, respectively, as they are accounted for based on intrinsic value rather than fair value. There was no weather derivatives impact for 2021. The pre-tax effects of energy-related derivatives not designated as hedging instruments were immaterial for all other Registrants for all years presented. Contingent Features The Registrants do not have any credit arrangements that would require material changes in payment schedules or terminations as a result of a credit rating downgrade. There are certain derivatives that could require collateral, but not accelerated payment, in the event of various credit rating changes of certain Southern Company subsidiaries. Generally, collateral may be provided by a Southern Company guaranty, letter of credit, or cash. At December 31, 2022, the Registrants had no collateral posted with derivative counterparties to satisfy these arrangements. For Southern Company and Southern Power, the fair value of interest rate derivative liabilities with contingent features and the maximum potential collateral requirements arising from the credit-risk-related contingent features, at a rating below BBB- and/or Baa3, were $78 million and $23 million, respectively, at December 31, 2022. For the traditional electric operating companies and Southern Power, energy-related derivative liabilities with contingent features and the maximum potential collateral requirements arising from the credit-risk-related contingent features, at a rating below BBB- and/or Baa3, were immaterial a t December 31, 2022. The maximum potential collateral requirements arising from the credit-risk-related contingent features for the traditional electric operating companies and Southern Power include certain agreements that could require collateral in the event that one or more Southern Company power pool participants has a credit rating change to below investment grade. Alabama Power and Southern Power maintain accounts with certain regional transmission organizations to facilitate financial derivative transactions and they may be required to post collateral based on the value of the positions in these accounts and the associated margin requirements. At December 31, 2022, cash collateral posted in these accounts was $15 million for Southern Power and immaterial for Alabama Power. Southern Company Gas maintains accounts with brokers or the clearing houses of certain exchanges to facilitate financial derivative transactions. Based on the value of the positions in these accounts and the associated margin requirements, Southern Company Gas may be required to deposit cash into these accounts. At December 31, 2022, cash collateral held on deposit in broker margin accounts was $41 million. The Registrants are exposed to losses related to financial instruments in the event of counterparties' nonperformance. The Registrants only enter into agreements and material transactions with counterparties that have investment grade credit ratings by Moody's and S&P or with counterparties who have posted collateral to cover potential credit exposure. The Registrants have also established risk management policies and controls to determine and monitor the creditworthiness of counterparties in order to mitigate their exposure to counterparty credit risk. Southern Company Gas uses established credit policies to determine and monitor the creditworthiness of counterparties, including requirements to post collateral or other credit security, as well as the quality of pledged collateral. Collateral or credit security is most often in the form of cash or letters of credit from an investment-grade financial institution, but may also include cash or U.S. government securities held by a trustee. Prior to entering a physical transaction, Southern Company Gas assigns its counterparties an internal credit rating and credit limit based on the counterparties' Moody's, S&P, and Fitch ratings, commercially available credit reports, and audited financial statements. Southern Company Gas may require counterparties to pledge additional collateral when deemed necessary. Southern Company Gas utilizes netting agreements whenever possible to mitigate exposure to counterparty credit risk. Netting agreements enable Southern Company Gas to net certain assets and liabilities by counterparty across product lines and against cash collateral, provided the netting and cash collateral agreements include such provisions. While the amounts due from, or owed to, counterparties are settled net, they are recorded on a gross basis on the balance sheet as energy marketing receivables and energy marketing payables. The Registrants do not anticipate a material adverse effect on their respective financial statements as a result of counterparty nonperformance.

ACQUISITIONS AND DISPOSITIONS

ACQUISITIONS AND DISPOSITIONS	12 Months Ended
	Dec. 31, 2022
Business Combination and Asset Acquisition [Abstract]
ACQUISITIONS AND DISPOSITIONS	ACQUISITIONS AND DISPOSITIONSNone of the dispositions discussed herein, both individually and combined, represented a strategic shift in operations for the applicable Registrants that has, or is expected to have, a major effect on its operations and financial results; therefore, none of the assets related to the sales have been classified as discontinued operations for any of the periods presented. Southern Power Southern Power's acquisition-related costs for the projects discussed under "Asset Acquisitions" and "Construction Projects" below were expensed as incurred and were not material for any of the years presented. There were no asset acquisitions during 2022. Asset Acquisitions Project Resource Seller Approximate Nameplate Capacity ( MW ) Location Southern COD PPA Asset Acquisitions During 2021 Deuel Harvest (a) Wind Invenergy Renewables LLC 300 Deuel County, SD 100% of Class B February 2021 25 years and 15 years Asset Acquisitions During 2020 Beech Ridge II (b) Wind Invenergy Renewables LLC 56 Greenbrier County, WV 100% of Class A May 12 years (a) In March 2021, Southern Power acquired a controlling interest in the project from Invenergy Renewables LLC and completed a tax equity transaction whereby it sold the Class A membership interests in the project. Southern Power consolidates the project's operating results in its financial statements and the tax equity partner and Invenergy Renewables LLC each own a noncontrolling interest. (b) In May 2020, Southern Power purchased a controlling interest and now consolidates the project's operating results in its financial statements. The Class B member owns the noncontrolling interest. Construction Projects During 2022, Southern Power completed construction of and placed in service the remaining 40 MWs of the Tranquillity battery energy storage facility and the remaining 15 MWs of the Garland battery energy storage facility. See Note 9 under "Lessor" for additional information. Project Resource Approximate Nameplate Capacity ( MW ) Location COD PPA Contract Period Projects Completed During 2022 Garland Solar Storage (a) Battery energy storage 88 Kern County, CA September 2021 through February 2022 (b) 20 years Tranquillity Solar Storage (a) Battery energy storage 72 Fresno County, CA November 2021 through March 2022 (c) 20 years Projects Completed During 2021 Glass Sands (d) Wind 118 Murray County, OK November 2021 12 years Projects Completed During 2020 Skookumchuck (e) Wind 136 Lewis and Thurston Counties, WA November 2020 20 years Reading (f) Wind 200 Osage and Lyon Counties, KS May 2020 12 years (a) In December 2020, Southern Power restructured its ownership of the project, while retaining the controlling interests, by contributing the Class A membership interests to an existing partnership and selling 100% of the Class B membership interests. During 2021, Southern Power further restructured its ownership in the battery energy storage projects and completed tax equity transactions whereby it sold the Class A membership interests in the projects. Southern Power consolidates each project's operating results in its financial statements and the tax equity partner and two other partners each own a noncontrolling interest. (b) The facility has a total capacity of 88 MWs, of which 73 MWs were placed in service in 2021 and 15 MWs were placed in service in February 2022. (c) The facility has a total capacity of 72 MWs, of which 32 MWs were placed in service in 2021 and 40 MWs were placed in service in March 2022. (d) In December 2020, Southern Power purchased 100% of the membership interests of the Glass Sands facility. (e) In November 2020, Southern Power completed a tax equity transaction whereby it received $121 million, resulting in 100% ownership of the Class B membership interests. Southern Power subsequently sold a noncontrolling interest in the Class B membership interests and now retains the controlling ownership interest in the facility. (f) In June 2020, Southern Power completed a tax equity transaction whereby it received $156 million and owns 100% of the Class B membership interests. Development Projects Southern Power purchased wind turbine equipment in 2016 and 2017 for deployment to development and construction projects. The significant majority of this equipment either has been deployed to projects that have been completed or has been sold to third parties. Gains on wind turbine equipment contributed to various equity method investments totaled approximately $37 million in 2021. Gains on wind turbine equipment sales were immaterial in 2020 and there were no sales in 2022. Sale of Plant Mankato In January 2020, Southern Power completed the sale of its equity interests in Plant Mankato (including the 385-MW expansion unit completed in 2019) to a subsidiary of Xcel Energy Inc. for a purchase price of approximately $663 million, including final working capital adjustments. The sale resulted in a gain of approximately $39 million ($23 million after tax). Plant Mankato represented an individually significant component of Southern Power. Southern Company Gas Sale of Sequent On July 1, 2021, Southern Company Gas affiliates completed the sale of Sequent to Williams Field Services Group for a total cash purchase price of $159 million, including final working capital adjustments. The pre-tax gain associated with th e transaction was approximately $121 million ($92 million after tax). The sale resulted in $85 million of additional tax expense. Sale of Pivotal LNG and Atlantic Coast Pipeline In March 2020, Southern Company Gas completed the sale of its interests in Pivotal LNG and Atlantic Coast Pipeline to Dominion Modular LNG Holdings, Inc. and Dominion Atlantic Coast Pipeline, LLC, respectively, with aggregate proceeds of $178 million, including final working capital adjustments. The loss associated with the transactions was immaterial. In connection with the sale, Southern Company Gas received two additional $5 million payments upon Dominion Modular LNG Holdings, Inc. meeting certain milestones related to Pivotal LNG in April 2021 and May 2022, respectively. Sale of Natural Gas Storage Facilities In December 2020, Southern Company Gas completed the sale of Jefferson Island to EnLink Midstream, LLC for a total purchase price of $33 million, including estimated working capital adjustments. The gain associated with the sale totaled $22 million pre-tax ($16 million after tax). On September 7, 2022, certain affiliates of Southern Company Gas entered into agreements to sell two natural gas storage facilities located in California and Texas for an aggregate purchase price of $186 million, plus working capital and certain other adjustments. The sale of the Texas facility was completed on November 18, 2022. Completion of the sale of the California facility is expected later in 2023 and is subject to certain closing conditions, including, among others, approval from the California Public Utilities Commission without a material burdensome condition. The ultimate outcome of this matter cannot be determined at this time. Completion of the sale of the Texas facility was subject to release of a Southern Company Gas parent guarantee, which was executed on October 20, 2022 and, as a result, Southern Company Gas recorded pre-tax impairment charges totaling approximately $131 million ($99 million after tax) in the fourth quarter 2022.
ACQUISITIONS AND DISPOSITIONS	ACQUISITIONS AND DISPOSITIONSNone of the dispositions discussed herein, both individually and combined, represented a strategic shift in operations for the applicable Registrants that has, or is expected to have, a major effect on its operations and financial results; therefore, none of the assets related to the sales have been classified as discontinued operations for any of the periods presented. Southern Company In connection with the annual impairment analysis of a leveraged lease investment during the fourth quarter 2020, Southern Company management concluded that the estimated residual value of the generation assets should be reduced due to significant uncertainty as to whether the related natural gas generation assets would continue to operate at the end of the lease term in 2040 and recorded a $34 million ($17 million after tax) impairment charge. Also during the fourth quarter 2020, Southern Company management initiated steps to sell the investment and reclassified it as held for sale. In the fourth quarter 2020 and the second quarter 2021, additional charges of $18 million ($14 million after tax) and $7 million ($6 million after tax), respectively, were recorded to further reduce the investment to its estimated fair value, less costs to sell. In October 2021, Southern Company completed the sale to the lessee for $45 million. No gain or loss was recognized on the sale; however, it did result in the recognition of approximately $16 million of additional tax benefits. In December 2021, Southern Company completed the termination of its leasehold interest in assets associated with its two international leveraged lease projects and received cash proceeds of approximately $673 million after the accelerated exercise of the lessee's purchase options. The pre-tax gain associated with the transaction was approximately $93 million ($99 million gain after tax). Alabama Power In 2020, Alabama Power completed its acquisition of the Central Alabama Generating Station, an approximately 885-MW combined cycle generation facility in Autauga County, Alabama. The transaction was accounted for as a business combination. The total purchase price was $461 million, of which $452 million was related to net assets recorded within property, plant, and equipment on the balance sheet and reflected in property additions within the investing section of the statement of cash flows. The remainder primarily related to inventory, current receivables, and accounts payable. Alabama Power assumed an existing power sales agreement under which the full output of the generating facility remains committed to another third party through May 2023. During the remaining term, the revenues from the power sales agreement are expected to substantially offset the associated costs of operation. See Note 9 under "Lessor" for additional information. On September 30, 2022, Alabama Power completed its acquisition of the Calhoun Generating Station, which was accounted for as an asset acquisition. The total purchase price was $179 million, of which $171 million was related to net assets recorded within property, plant, and equipment on the balance sheet and reflected in property additions within the investing section of the statement of cash flows. The remainder primarily related to fossil fuel stock and materials and supplies. See Note 2 under "Alabama Power – Certificates of Convenience and Necessity" for additional information. Southern Power Southern Power's acquisition-related costs for the projects discussed under "Asset Acquisitions" and "Construction Projects" below were expensed as incurred and were not material for any of the years presented. There were no asset acquisitions during 2022. Asset Acquisitions Project Resource Seller Approximate Nameplate Capacity ( MW ) Location Southern COD PPA Asset Acquisitions During 2021 Deuel Harvest (a) Wind Invenergy Renewables LLC 300 Deuel County, SD 100% of Class B February 2021 25 years and 15 years Asset Acquisitions During 2020 Beech Ridge II (b) Wind Invenergy Renewables LLC 56 Greenbrier County, WV 100% of Class A May 12 years (a) In March 2021, Southern Power acquired a controlling interest in the project from Invenergy Renewables LLC and completed a tax equity transaction whereby it sold the Class A membership interests in the project. Southern Power consolidates the project's operating results in its financial statements and the tax equity partner and Invenergy Renewables LLC each own a noncontrolling interest. (b) In May 2020, Southern Power purchased a controlling interest and now consolidates the project's operating results in its financial statements. The Class B member owns the noncontrolling interest. Construction Projects During 2022, Southern Power completed construction of and placed in service the remaining 40 MWs of the Tranquillity battery energy storage facility and the remaining 15 MWs of the Garland battery energy storage facility. See Note 9 under "Lessor" for additional information. Project Resource Approximate Nameplate Capacity ( MW ) Location COD PPA Contract Period Projects Completed During 2022 Garland Solar Storage (a) Battery energy storage 88 Kern County, CA September 2021 through February 2022 (b) 20 years Tranquillity Solar Storage (a) Battery energy storage 72 Fresno County, CA November 2021 through March 2022 (c) 20 years Projects Completed During 2021 Glass Sands (d) Wind 118 Murray County, OK November 2021 12 years Projects Completed During 2020 Skookumchuck (e) Wind 136 Lewis and Thurston Counties, WA November 2020 20 years Reading (f) Wind 200 Osage and Lyon Counties, KS May 2020 12 years (a) In December 2020, Southern Power restructured its ownership of the project, while retaining the controlling interests, by contributing the Class A membership interests to an existing partnership and selling 100% of the Class B membership interests. During 2021, Southern Power further restructured its ownership in the battery energy storage projects and completed tax equity transactions whereby it sold the Class A membership interests in the projects. Southern Power consolidates each project's operating results in its financial statements and the tax equity partner and two other partners each own a noncontrolling interest. (b) The facility has a total capacity of 88 MWs, of which 73 MWs were placed in service in 2021 and 15 MWs were placed in service in February 2022. (c) The facility has a total capacity of 72 MWs, of which 32 MWs were placed in service in 2021 and 40 MWs were placed in service in March 2022. (d) In December 2020, Southern Power purchased 100% of the membership interests of the Glass Sands facility. (e) In November 2020, Southern Power completed a tax equity transaction whereby it received $121 million, resulting in 100% ownership of the Class B membership interests. Southern Power subsequently sold a noncontrolling interest in the Class B membership interests and now retains the controlling ownership interest in the facility. (f) In June 2020, Southern Power completed a tax equity transaction whereby it received $156 million and owns 100% of the Class B membership interests. Development Projects Southern Power purchased wind turbine equipment in 2016 and 2017 for deployment to development and construction projects. The significant majority of this equipment either has been deployed to projects that have been completed or has been sold to third parties. Gains on wind turbine equipment contributed to various equity method investments totaled approximately $37 million in 2021. Gains on wind turbine equipment sales were immaterial in 2020 and there were no sales in 2022. Sale of Plant Mankato In January 2020, Southern Power completed the sale of its equity interests in Plant Mankato (including the 385-MW expansion unit completed in 2019) to a subsidiary of Xcel Energy Inc. for a purchase price of approximately $663 million, including final working capital adjustments. The sale resulted in a gain of approximately $39 million ($23 million after tax). Plant Mankato represented an individually significant component of Southern Power. Southern Company Gas Sale of Sequent On July 1, 2021, Southern Company Gas affiliates completed the sale of Sequent to Williams Field Services Group for a total cash purchase price of $159 million, including final working capital adjustments. The pre-tax gain associated with th e transaction was approximately $121 million ($92 million after tax). The sale resulted in $85 million of additional tax expense. Sale of Pivotal LNG and Atlantic Coast Pipeline In March 2020, Southern Company Gas completed the sale of its interests in Pivotal LNG and Atlantic Coast Pipeline to Dominion Modular LNG Holdings, Inc. and Dominion Atlantic Coast Pipeline, LLC, respectively, with aggregate proceeds of $178 million, including final working capital adjustments. The loss associated with the transactions was immaterial. In connection with the sale, Southern Company Gas received two additional $5 million payments upon Dominion Modular LNG Holdings, Inc. meeting certain milestones related to Pivotal LNG in April 2021 and May 2022, respectively. Sale of Natural Gas Storage Facilities In December 2020, Southern Company Gas completed the sale of Jefferson Island to EnLink Midstream, LLC for a total purchase price of $33 million, including estimated working capital adjustments. The gain associated with the sale totaled $22 million pre-tax ($16 million after tax). On September 7, 2022, certain affiliates of Southern Company Gas entered into agreements to sell two natural gas storage facilities located in California and Texas for an aggregate purchase price of $186 million, plus working capital and certain other adjustments. The sale of the Texas facility was completed on November 18, 2022. Completion of the sale of the California facility is expected later in 2023 and is subject to certain closing conditions, including, among others, approval from the California Public Utilities Commission without a material burdensome condition. The ultimate outcome of this matter cannot be determined at this time. Completion of the sale of the Texas facility was subject to release of a Southern Company Gas parent guarantee, which was executed on October 20, 2022 and, as a result, Southern Company Gas recorded pre-tax impairment charges totaling approximately $131 million ($99 million after tax) in the fourth quarter 2022.

SEGMENT AND RELATED INFORMATION

SEGMENT AND RELATED INFORMATION	12 Months Ended
	Dec. 31, 2022
Segment Reporting [Abstract]
SEGMENT AND RELATED INFORMATION	SEGMENT AND RELATED INFORMATION Southern Company Southern Company's reportable business segments are the sale of electricity by the traditional electric operating companies, the sale of electricity in the competitive wholesale market by Southern Power, and the sale of natural gas and other complementary products and services by Southern Company Gas. Revenues from sales by Southern Power to the traditional electric operating companies were $875 million, $515 million, and $364 million in 2022, 2021, and 2020, respectively. Revenues from sales of natural gas from Southern Company Gas to the traditional electric operating companies were immaterial for all periods presented. Revenues from sales of natural gas from Southern Company Gas (prior to its sale of Sequent) to Southern Power were $18 million and $26 million in 2021 and 2020, respectively. The "All Other" column includes the Southern Company parent entity, which does not allocate operating expenses to business segments. Also, this category includes segments below the quantitative threshold for separate disclosure. These segments include providing distributed energy and resilience solutions and deploying microgrids for commercial, industrial, governmental, and utility customers, as well as investments in telecommunications and leveraged lease projects. All other inter-segment revenues are not material. Financial data for business segments and products and services for the years ended December 31, 2022, 2021, and 2020 was as follows: Electric Utilities Traditional Southern Eliminations Total Southern Company Gas All Eliminations Consolidated (in millions) 2022 Operating revenues $ 20,408 $ 3,369 $ (904) $ 22,873 $ 5,962 $ 593 $ (149) $ 29,279 Depreciation and amortization 2,513 516 — 3,029 559 75 — 3,663 Interest income 44 3 — 47 3 16 (7) 59 Earnings from equity method investments — — — — 148 3 — 151 Interest expense 929 138 — 1,067 263 694 (2) 2,022 Income taxes (benefit) 828 20 — 848 180 (233) — 795 Segment net income (loss) (a)(b)(c)(d) 3,318 354 — 3,672 572 (711) (9) 3,524 Goodwill — 2 — 2 5,015 144 — 5,161 Total assets 95,861 13,081 (659) 108,283 24,621 2,665 (678) 134,891 2021 Operating revenues $ 16,614 $ 2,216 $ (530) $ 18,300 $ 4,380 $ 582 $ (149) $ 23,113 Depreciation and amortization 2,436 517 — 2,953 536 76 — 3,565 Interest income 20 1 — 21 — 4 (3) 22 Earnings from equity method investments 1 — — 1 50 24 1 76 Interest expense 821 147 — 968 238 631 — 1,837 Income taxes (benefit) 232 (13) — 219 275 (227) — 267 Segment net income (loss) (a)(b)(e)(f)(g)(h) 1,981 266 — 2,247 539 (384) (9) 2,393 Goodwill — 2 — 2 5,015 263 — 5,280 Total assets 89,051 13,390 (667) 101,774 23,560 2,975 (775) 127,534 2020 Operating revenues $ 15,135 $ 1,733 $ (371) $ 16,497 $ 3,434 $ 596 $ (152) $ 20,375 Depreciation and amortization 2,447 494 — 2,941 500 77 — 3,518 Interest income 26 4 — 30 5 6 (4) 37 Earnings from equity method investments — — — — 141 12 — 153 Interest expense 825 151 — 976 231 614 — 1,821 Income taxes (benefit) 514 3 — 517 173 (297) — 393 Segment net income (loss) (a)(b)(h)(i)(j) 2,877 238 — 3,115 590 (592) 6 3,119 Goodwill — 2 — 2 5,015 263 — 5,280 Total assets 85,486 13,235 (680) 98,041 22,630 3,168 (904) 122,935 (a) Attributable to Southern Company. (b) For the traditional electric operating companies, includes pre-tax charges to income at Georgia Power for the estimated probable loss associated with the construction of Plant Vogtle Units 3 and 4 of $183 million ($137 million after tax) in 2022, $1.7 billion ($1.3 billion after tax) in 2021, and $325 million ($242 million after tax) in 2020. See Note 2 under "Georgia Power – Nuclear Construction" for additional information. (c) For Southern Company Gas, includes pre-tax impairment charges totaling approximately $131 million ($99 million after tax) related to the sale of natural gas storage facilities. See Note 15 under "Southern Company Gas" for additional information. (d) For the "All Other" column, includes a $119 million goodwill impairment loss (pre-tax and after tax) at PowerSecure. See Note 1 under "Goodwill and Other Intangible Assets and Liabilities" for additional information. (e) For Southern Power, includes gains on wind turbine equipment contributed to various equity method investments totaling approximately $37 million pre-tax ($28 million after tax). See Notes 7 and 15 under "Southern Power" for additional information. (f) For Southern Company Gas, includes a pre-tax gain of $121 million ($92 million after tax) related to its sale of Sequent, as well as the resulting $85 million of additional tax expense due to changes in state apportionment rates, and pre-tax impairment charges totaling $84 million ($67 million after tax) related to its equity method investment in the PennEast Pipeline project. See Notes 7 and 15 under "Southern Company Gas" for additional information. (g) For the "All Other" column, includes a pre-tax gain of $93 million ($99 million gain after tax) associated with the termination of two leveraged leases projects. See Note 15 under "Southern Company" for additional information. (h) For the "All Other" column, includes pre-tax impairment charges totaling $7 million ($6 million after tax) in 2021 and $206 million ($105 million after tax) in 2020 related to leveraged lease investments. See Notes 9 and 15 under "Southern Company Leveraged Lease" and "Southern Company," respectively, for additional information. (i) For Southern Power, includes a $39 million pre-tax gain ($23 million gain after tax) on the sale of Plant Mankato. See Note 15 under "Southern Power" for additional information. (j) For Southern Company Gas, includes a $22 million pre-tax gain ($16 million gain after tax) on the sale of Jefferson Island. See Note 15 under "Southern Company Gas" for additional information. Products and Services Electric Utilities' Revenues Year Retail Wholesale Other Total (in millions) 2022 $ 18,197 $ 3,641 $ 1,035 $ 22,873 2021 14,852 2,455 993 18,300 2020 13,643 1,945 909 16,497 Southern Company Gas' Revenues Year Gas Gas All Other Total (in millions) 2022 $ 5,240 $ 638 $ 84 $ 5,962 2021 3,656 475 249 4,380 2020 2,902 408 124 3,434 Southern Company Gas Southern Company Gas manages its business through three reportable segments – gas distribution operations, gas pipeline investments, and gas marketing services. Prior to the sale of Sequent on July 1, 2021, Southern Company Gas' reportable segments also included wholesale gas services. The non-reportable segments are combined and presented as all other. See Note 15 under "Southern Company Gas" for additional information on the disposition activities described herein. Gas distribution operations is the largest component of Southern Company Gas' business and includes natural gas local distribution utilities that construct, manage, and maintain intrastate natural gas pipelines and gas distribution facilities in four states. Gas pipeline investments consists of joint ventures in natural gas pipeline investments including a 50% interest in SNG and a 50% joint ownership interest in the Dalton Pipeline. These natural gas pipelines enable the provision of diverse sources of natural gas supplies to the customers of Southern Company Gas. Gas pipeline investments also includes a 20% ownership interest in the PennEast Pipeline project, which was cancelled in September 2021, and through its March 2020 sale, included a 5% ownership interest in the Atlantic Coast Pipeline construction project. See Notes 5 and 7 for additional information. Through July 1, 2021, wholesale gas services provided natural gas asset management and/or related logistics services for each of Southern Company Gas' utilities except Nicor Gas as well as for non-affiliated companies. Additionally, wholesale gas services engaged in natural gas storage and gas pipeline arbitrage and related activities. Gas marketing services provides natural gas marketing to end-use customers primarily in Georgia and Illinois through SouthStar. The all other column includes segments and subsidiaries that fall below the quantitative threshold for separate disclosure, including storage and fuels operations. The all other column included a natural gas storage facility in Texas through its sale on November 18, 2022, Jefferson Island through its sale in December 2020, and Pivotal LNG through its sale in March 2020. See Note 15 to the financial statements under "Southern Company Gas" for additional information, including the sale of a natural gas storage facility in California expected to be completed later in 2023 . Financial data for business segments for the years ended December 31, 2022, 2021, and 2020 was as follows: Gas Distribution Operations Gas Pipeline Investments Wholesale Gas Services (a) Gas Marketing Services Total All Other Eliminations Consolidated (in millions) 2022 Operating revenues $ 5,267 $ 32 $ — $ 638 $ 5,937 $ 55 $ (30) $ 5,962 Depreciation and amortization 516 5 — 16 537 22 — 559 Operating income (loss) 803 21 — 133 957 (135) (8) 814 Earnings from equity method investments — 148 — — 148 — — 148 Interest expense 229 27 — 3 259 4 — 263 Income taxes (benefit) 145 35 — 37 217 (37) — 180 Segment net income (loss) (b) 470 107 — 94 671 (99) — 572 Total assets 22,040 1,577 — 1,616 25,233 8,943 (9,555) 24,621 2021 Operating revenues $ 3,679 $ 32 $ 188 $ 475 $ 4,374 $ 38 $ (32) $ 4,380 Depreciation and amortization 482 5 — 18 505 31 — 536 Operating income (loss) 708 21 241 125 1,095 (40) — 1,055 Earnings from equity method investments — 50 — — 50 — — 50 Interest expense 207 25 2 3 237 1 — 238 Income taxes (benefit) 120 27 32 34 213 62 — 275 Segment net income (loss) (c)(d)(e) 412 19 107 88 626 (87) — 539 Total assets 20,917 1,467 31 1,556 23,971 12,114 (12,525) 23,560 2020 Operating revenues $ 2,952 $ 32 $ 74 $ 408 $ 3,466 $ 36 $ (68) $ 3,434 Depreciation and amortization 442 5 1 22 470 30 — 500 Operating income (loss) 655 20 20 119 814 (7) 5 812 Earnings from equity method investments — 141 — — 141 — — 141 Interest expense 192 29 4 3 228 3 — 231 Income taxes (benefit) 114 33 3 28 178 (5) — 173 Segment net income (loss) (f) 390 99 14 89 592 (2) — 590 Total assets 19,090 1,597 850 1,503 23,040 11,336 (11,746) 22,630 (a) As a result of the sale of Sequent, wholesale gas services is no longer a reportable segment in 2022. Prior to the sale of Sequent, the revenues for wholesale gas services were netted with costs associated with its energy and risk management activities. A reconciliation of operating revenues and intercompany revenues is shown in the following table. Third Party Gross Revenues Intercompany Revenues Total Gross Revenues Less Gross Gas Costs Operating Revenues (in millions) 2021 $ 3,881 $ 90 $ 3,971 $ 3,783 $ 188 2020 4,544 115 4,659 4,585 74 (b) For the "All Other" column, includes pre-tax impairment charges totaling approximately $131 million ($99 million after tax) related to the sale of natural gas storage facilities. See Note 15 under "Southern Company Gas" for additional information. (c) For gas pipeline investments, includes pre-tax impairment charges totaling $84 million ($67 million after tax) related to the equity method investment in the PennEast Pipeline project. See Note 7 under "Southern Company Gas" for additional information. (d) For wholesale gas services, includes a pre-tax gain of $121 million ($92 million after tax) related to the sale of Sequent. (e) For the "All Other" column, includes $85 million of additional tax expense as a result of the sale of Sequent. (f) For the "All Other" column include s a $22 million pre-tax gain ($16 million g ain after tax) on the sale of Jefferson Island.

VALUATION AND QUALIFYING ACCOUN

VALUATION AND QUALIFYING ACCOUNTS	12 Months Ended
	Dec. 31, 2022
SEC Schedule, 12-09, Valuation and Qualifying Accounts [Abstract]
VALUATION AND QUALIFYING ACCOUNTS	SCHEDULE II — VALUATION AND QUALIFYING ACCOUNTS FOR THE YEARS ENDED DECEMBER 31, 2022, 2021, AND 2020 Additions Description Balance at Beginning of Period Charged to Income Charged to Other Accounts Deductions (a) Balance at End of Period (in millions) Provision for uncollectible accounts: Southern Company (b) 2022 $ 78 $ 71 $ (1) $ 77 $ 71 2021 118 51 (23) 68 78 2020 49 78 27 36 118 Alabama Power 2022 $ 14 $ 10 $ — $ 10 $ 14 2021 43 (7) — 22 14 2020 22 25 — 4 43 Georgia Power (b) 2022 $ 2 $ 21 $ — $ 20 $ 3 2021 26 16 (23) 17 2 2020 2 14 23 13 26 Mississippi Power 2022 $ 1 $ 1 $ 1 $ 2 $ 1 2021 1 1 — 1 1 2020 1 1 — 1 1 Southern Power 2022 $ 5 $ (2) $ — $ 2 $ 1 2021 — 5 — — 5 2020 — — — — — Southern Company Gas 2022 $ 39 $ 55 $ — $ 44 $ 50 2021 40 26 — 27 39 2020 18 35 4 17 40 (a) Deductions represent write-offs of accounts considered to be uncollectible, less recoveries of amounts previously written off. (b) During 2020, Georgia Power recorded $23 million of expected bad debt related to the COVID-19 pandemic to a regulatory asset in accordance with orders from the Georgia PSC. During 2021, based on a review of bad debt amounts under a Georgia PSC-approved methodology, Georgia Power reversed substantially all of the amount recorded in 2020. See Note 2 to the financial statements under "Georgia Power – Deferral of Incremental COVID-19 Costs" in Item 8 herein for additional information. SCHEDULE II — VALUATION AND QUALIFYING ACCOUNTS (CONTINUED) FOR THE YEARS ENDED DECEMBER 31, 2022, 2021, AND 2020 Additions Description Balance at Beginning of Period Charged to Income Charged to Other Accounts Deductions Balance at End of Period (in millions) Tax valuation allowance (net state): Southern Company (a)(b) 2022 $ 169 $ 68 $ (30) $ — $ 207 2021 112 57 — — 169 2020 113 — — 1 112 Georgia Power (a) 2022 $ 58 $ 70 $ (30) $ — $ 98 2021 28 30 — — 58 2020 28 — — — 28 Mississippi Power (b) 2022 $ 32 $ — $ — $ — $ 32 2021 32 — — — 32 2020 32 — — — 32 Southern Power (b) 2022 $ 21 $ — $ — $ — $ 21 2021 27 (6) — — 21 2020 29 (1) — 1 27 Southern Company Gas (b) 2022 $ 7 $ — $ — $ — $ 7 2021 4 3 — — 7 2020 4 — — — 4 (a) In 2018, Georgia Power established a valuation allowance for certain Georgia state tax credits expected to expire prior to being fully utilized, which has been adjusted in subsequent years as a result of changes in projected state taxable income. (b) Associated with a state net operating loss carryforward expected to expire prior to being fully utilized. See Note 10 to the financial statements in Item 8 herein for additional information.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
General	General Southern Company is the parent company of three traditional electric operating companies, as well as Southern Power, Southern Company Gas, SCS, Southern Linc, Southern Holdings, Southern Nuclear, PowerSecure, and other direct and indirect subsidiaries. The traditional electric operating companies – Alabama Power, Georgia Power, and Mississippi Power – are vertically integrated utilities providing electric service in three Southeastern states. Southern Power develops, constructs, acquires, owns, and manages power generation assets, including renewable energy projects, and sells electricity at market-based rates in the wholesale market. Southern Company Gas distributes natural gas through natural gas distribution utilities, including Nicor Gas (Illinois), Atlanta Gas Light (Georgia), Virginia Natural Gas, and Chattanooga Gas (Tennessee). Southern Company Gas is also involved in several other complementary businesses including gas pipeline investments and gas marketing services. Prior to the sale of Sequent on July 1, 2021, these businesses also included wholesale gas services. SCS, the system service company, provides, at cost, specialized services to Southern Company and its subsidiary companies. Southern Linc provides digital wireless communications for use by Southern Company and its subsidiary companies and also markets these services to the public and provides fiber optics services within the Southeast. Southern Holdings is an intermediate holding company subsidiary. Southern Nuclear operates and provides services to the Southern Company system's nuclear power plants, including Alabama Power's Plant Farley and Georgia Power's Plant Hatch and Plant Vogtle Units 1 and 2, and is currently managing construction and start-up of Plant Vogtle Units 3 and 4, which are co-owned by Georgia Power. PowerSecure develops distributed energy and resilience solutions and deploys microgrids for commercial, industrial, governmental, and utility customers. See Note 15 for information regarding the sale of Sequent. The Registrants' financial statements reflect investments in subsidiaries on a consolidated basis. Intercompany transactions have been eliminated in consolidation. The equity method is used for investments in entities in which a Registrant has significant influence but does not have control and for VIEs where a Registrant has an equity investment but is not the primary beneficiary. Southern Power has controlling ownership in certain legal entities for which the contractual provisions represent profit-sharing arrangements because the allocations of cash distributions and tax benefits are not based on fixed ownership percentages. For these arrangements, the noncontrolling interest is accounted for under a balance sheet approach utilizing the HLBV method. The HLBV method calculates each partner's share of income based on the change in net equity the partner can legally claim in a HLBV at the end of the period compared to the beginning of the period. See "Variable Interest Entities" herein and Note 7 for additional information. The traditional electric operating companies, Southern Power, certain subsidiaries of Southern Company Gas, and certain other subsidiaries are subject to regulation by the FERC, and the traditional electric operating companies and the natural gas distribution utilities are also subject to regulation by their respective state PSCs or other applicable state regulatory agencies. As such, the respective financial statements of the applicable Registrants reflect the effects of rate regulation in accordance with GAAP and comply with the accounting policies and practices prescribed by relevant state PSCs or other applicable state regulatory agencies. The preparation of financial statements in conformity with GAAP requires the use of estimates, and the actual results may differ from those estimates. Certain prior years' data presented in the financial statements have been reclassified to conform to the current year presentation. These reclassifications had no impact on the Registrants' results of operations, financial position, or cash flows.
Recently Adopted Accounting Standards	Recently Adopted Accounting Standards In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting (ASU 2020-04) providing temporary guidance to ease the potential burden in accounting for reference rate reform primarily resulting from the discontinuation of LIBOR, which began phasing out on December 31, 2021. The discontinuation date of the overnight 1-, 3-, 6-, and 12-month tenors of LIBOR is June 30, 2023, which is beyond the original effective date of ASU 2020-04; therefore, on December 21, 2022, the FASB issued ASU 2022-06, Reference Rate Reform (Topic 848): Deferral of the Sunset Date of Topic 848 (ASU 2022-06) to defer the sunset date of ASU 2020-04 from December 31, 2022 to December 31, 2024. The amendments are elective and apply to all entities that have contracts, hedging relationships, and other transactions that reference LIBOR or another reference rate expected to be discontinued. The guidance (i) simplifies accounting analyses under current GAAP for contract modifications; (ii) simplifies the assessment of hedge effectiveness and allows hedging relationships affected by reference rate reform to continue; and (iii) allows a one-time election to sell or transfer debt securities classified as held to maturity that reference a rate affected by reference rate reform. An entity may elect to apply the amendments prospectively from March 12, 2020 through December 31, 2024 by accounting topic. The Registrants have elected to apply the amendments to modifications of debt and derivative arrangements that meet the scope of ASU 2020-04 and ASU 2022-06. The Registrants currently reference LIBOR for certain debt and hedging arrangements. In addition, certain provisions in PPAs at Southern Power include references to LIBOR. Contract language has been, or is expected to be, incorporated into each of these agreements to address the transition to an alternative rate for agreements that will be in place at the transition date. No material impacts are expected from modifications to the arrangements and effective hedging relationships are expected to continue. See Note 14 under "Interest Rate Derivatives" for additional information.
Affiliate Transactions	Affiliate TransactionsThe traditional electric operating companies, Southern Power, and Southern Company Gas have agreements with SCS under which certain of the following services are rendered to them at direct or allocated cost: general executive and advisory, general and design engineering, operations, purchasing, accounting, finance, treasury, legal, tax, information technology, marketing, auditing, insurance and pension administration, human resources, systems and procedures, digital wireless communications, cellular tower space, and other services with respect to business and operations, construction management, and Southern Company power pool transactions. These costs are primarily included in other operations and maintenance expenses or capitalized to property, plant, and equipment.
Regulatory Assets and Liabilities	Regulatory Assets and Liabilities The traditional electric operating companies and the natural gas distribution utilities are subject to accounting requirements for the effects of rate regulation. Regulatory assets represent probable future revenues associated with certain costs that are expected to be recovered from customers through the ratemaking process. Regulatory liabilities represent costs recovered that are expected to be incurred in the future or probable future reductions in revenues associated with amounts that are expected to be credited to customers through the ratemaking process. In the event that a portion of a traditional electric operating company's or a natural gas distribution utility's operations is no longer subject to applicable accounting rules for rate regulation, such company would be required to write off to income or reclassify to AOCI related regulatory assets and liabilities that are not specifically recoverable through regulated rates. In addition, the
Revenues	Revenues The Registrants generate revenues from a variety of sources which are accounted for under various revenue accounting guidance, including revenue from contracts with customers, lease, derivative, and regulatory accounting. See Notes 4, 9, and 14 for additional information. Traditional Electric Operating Companies The majority of the revenues of the traditional electric operating companies are generated from contracts with retail electric customers. These revenues, generated from the integrated service to deliver electricity when and if called upon by the customer, are recognized as a single performance obligation satisfied over time, at a tariff rate, and as electricity is delivered to the customer during the month. Unbilled revenues related to retail sales are accrued at the end of each fiscal period. Retail rates may include provisions to adjust revenues for fluctuations in fuel costs, fuel hedging, the energy component of purchased power costs, and certain other costs. Revenues are adjusted for differences between these actual costs and amounts billed in current regulated rates. Under or over recovered regulatory clause revenues are recorded in the balance sheets and are recovered from or returned to customers, respectively, through adjustments to the billing factors. See Note 2 for additional information regarding regulatory matters of the traditional electric operating companies. Wholesale capacity revenues from PPAs are recognized in amounts billable under the contract terms. Energy and other revenues are generally recognized as services are provided. The contracts for capacity and energy in a wholesale PPA have multiple performance obligations where the contract's total transaction price is allocated to each performance obligation based on the standalone selling price. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, the traditional electric operating companies recognize revenue as the performance obligations are satisfied over time as electricity is delivered to the customer or as generation capacity is available to the customer. For both retail and wholesale revenues, the traditional electric operating companies have elected to recognize revenue for their sales of electricity and capacity using the invoice practical expedient as they generally have a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and that may be invoiced. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of the Registrants' performance obligation. Southern Power Southern Power sells capacity and energy at rates specified under contractual terms in long-term PPAs. These PPAs are accounted for as leases, non-derivatives, or normal sale derivatives. Capacity revenues from PPAs classified as operating leases are recognized on a straight-line basis over the term of the agreement. Energy revenues are recognized in the period the energy is delivered. Capacity revenues from PPAs classified as sales-type leases are recognized by accounting for interest income on the net investment in the lease. Southern Power's non-lease contracts commonly include capacity and energy which are considered separate performance obligations. In these contracts, the total transaction price is allocated to each performance obligation based on the standalone selling price. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, Southern Power recognizes revenue as the performance obligations are satisfied over time, as electricity is delivered to the customer or as generation capacity is made available to the customer. Southern Power generally has a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and may recognize revenue in the amount to which the entity has a right to invoice. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of Southern Power's performance obligation. When multiple contracts exist with the same counterparty, the revenues from each contract are accounted for as separate arrangements. Southern Power may also enter into contracts to sell short-term capacity in the wholesale electricity markets. These sales are generally classified as mark-to-market derivatives and net unrealized gains and losses on such contracts are recorded in wholesale revenues. See Note 14 and "Financial Instruments" herein for additional information. Southern Company Gas Gas Distribution Operations Southern Company Gas records revenues when goods or services are provided to customers. Those revenues are based on rates approved by the state regulatory agencies of the natural gas distribution utilities. Atlanta Gas Light operates in a deregulated natural gas market wher eby M arketers, rather than a traditional utility, sell natural gas to end-use customers in Georgia and handle customer billing functions. As required by the Georgia PSC, Atlanta Gas Light bills Marketers in equal monthly installments for each residential, commercial, and industrial end-use customer's distribution costs as well as for capacity costs utilizing a seasonal rate design for the calculation of each residential end-use customer's annual straight-fixed-variable charge, which reflects the historic volumetric usage pattern for the entire residential class. The majority of the revenues of Southern Company Gas are generated from contracts with natural gas distribution customers. Revenues from this integrated service to deliver gas when and if called upon by the customer are recognized as a single performance obligation satisfied over time and are recognized at a tariff rate as gas is delivered to the customer during the month. The standalone selling price is primarily determined by the price charged to customers for the specific goods or services transferred with the performance obligations. Generally, Southern Company Gas recognizes revenue as the performance obligations are satisfied over time as natural gas is delivered to the customer. The performance obligations related to wholesale gas services are satisfied, and revenue is recognized, at a point in time when natural gas is delivered to the customer. Southern Company Gas has elected to recognize revenue for sales of gas using the invoice practical expedient as it generally has a right to consideration in an amount that corresponds directly with the value to the customer of the performance completed to date and that may be invoiced. Payment for goods and services rendered is typically due in the subsequent month following satisfaction of Southern Company Gas' performance obligation. With the exception of Atlanta Gas Light, the natural gas distribution utilities have rate structures that include volumetric rate designs that allow the opportunity to recover certain costs based on gas usage. Revenues from sales and transportation services are recognized in the same period in which the related volumes are delivered to customers. Revenues from residential and certain commercial and industrial customers are recognized on the basis of scheduled meter readings. Additionally, unbilled revenues are recognized for estimated deliveries of gas not yet billed to these customers, from the last bill date to the end of the accounting period. For other commercial and industrial customers, revenues are based on actual deliveries through the end of the period. The tariffs for the natural gas distribution utilities include provisions which allow for the recognition of certain revenues prior to the time such revenues are billed to customers. These provisions are referred to as alternative revenue programs and provide for the recognition of certain revenues prior to billing, as long as the amounts recognized will be collected from customers within 24 months of recognition. Revenue related to alternative revenue programs was $(5) million, $11 million, and $3 million in 2022, 2021, and 2020, respectively. These programs are as follows: • Weather normalization adjustments – reduce customer bills when winter weather is colder than normal and increase customer bills when weather is warmer than normal and are included in the tariffs for Virginia Natural Gas and Chattanooga Gas; • Revenue normalization mechanisms – mitigate the impact of conservation and declining customer usage and are contained in the tariffs for Virginia Natural Gas and Nicor Gas; and • Revenue true-up adjustment – included within the provisions of the GRAM program in which Atlanta Gas Light participates as a short-term alternative to formal rate case filings, the revenue true-up feature provides for a positive (or negative) adjustment to record revenue in the amount of any variance to budgeted revenues, which are submitted and approved annually as a requirement of GRAM. Such adjustments are reflected in customer billings in a subsequent program year. Wholesale Gas Services Prior to the sale of Sequent on July 1, 2021, Southern Company Gas netted revenues from energy and risk management activities with the associated costs. Profits from sales between segments were eliminated and recognized as goods or services sold to end-use customers. Southern Company Gas recorded wholesale gas services' transactions that qualified as derivatives at fair value with changes in fair value recognized in earnings in the period of change and characterized as unrealized gains or losses. Gains and losses on derivatives held for energy trading purposes were presented on a net basis in revenue. See Note 15 under "Southern Company Gas" for additional information on the sale of Sequent. Gas Marketing Services Southern Company Gas recognizes revenues from natural gas sales and transportation services in the same period in which the related volumes are delivered to customers and recognizes sales revenues from residential and certain commercial and industrial customers on the basis of scheduled meter readings. Southern Company Gas also recognizes unbilled revenues for estimated deliveries of gas not yet billed to these customers from the most recent meter reading date to the end of the accounting period. For other commercial and industrial customers and for all wholesale customers, revenues are based on actual deliveries during the period. Southern Company Gas recognizes revenues on 12-month utility-bill management contracts as the lesser of cumulative earned or cumulative billed amounts. Concentration of Revenue Southern Company, Alabama Power, Georgia Power, Mississippi Power (with the exception of its full requirements cost-based MRA electric tariffs described below), Southern Power, and Southern Company Gas each have a diversified base of customers and no single customer or industry comprises 10% or more of each company's revenues. Mississippi Power provides service under long-term contracts with rural electric cooperative associations and a municipality located in southeastern Mississippi under requirements cost-based MRA electric tariffs, which are subject to regulation by the FERC. The contracts with these wholesale customers represented 12.4% of Mississippi Power's total operating revenues in 2022. Historically, these wholesale customers have acted as a group and any changes in contractual relationships for one customer are likely to be followed by the other wholesale customers.
Fuel Costs	Fuel Costs Fuel costs for the traditional electric operating companies and Southern Power are expensed as the fuel is used. Fuel expense generally includes fuel transportation costs and the cost of purchased emissions allowances as they are used. For Alabama Power and Georgia Power, fuel expense also includes the amortization of the cost of nuclear fuel. For the traditional electric operating companies, fuel costs also include gains and/or losses from fuel-hedging programs as approved by their respective state PSCs.
Cost of Natural Gas	Cost of Natural Gas Excluding Atlanta Gas Light, which does not sell natural gas to end-use customers, Southern Company Gas charges its utility customers for natural gas consumed using natural gas cost recovery mechanisms set by the applicable state regulatory agencies. Under these mechanisms, all prudently-incurred natural gas costs are passed through to customers without markup, subject to regulatory review. Southern Company Gas defers or accrues the difference between the actual cost of natural gas and the amount of commodity revenue earned in a given period such that no operating income is recognized related to these costs. The deferred or accrued amount is either billed or refunded to customers prospectively through adjustments to the commodity rate. Deferred and accrued natural gas costs are included in the balance sheets as regulatory assets and regulatory liabilities, respectively. Southern Company Gas' gas marketing services' customers are charged for actual or estimated natural gas consumed. Within cost of natural gas, Southern Company Gas also includes costs of lost and unaccounted for gas, adjustments to reduce the value of inventories to market value, and gains and losses associated with certain derivatives.
Income Taxes and Other Taxes	Income Taxes The Registrants use the liability method of accounting for deferred income taxes and provide deferred income taxes for all significant income tax temporary differences. In accordance with regulatory requirements, deferred federal ITCs for the traditional electric operating companies are amortized over the average life of the related property, with such amortization normally applied as a credit to reduce depreciation and amortization in the statements of income. Southern Power's and the natural gas distribution utilities' deferred federal ITCs, as well as certain state ITCs for Nicor Gas, are amortized to income tax expense over the life of the respective asset. Under current tax law, certain projects at Southern Power related to the construction of renewable facilities are eligible for federal ITCs. Southern Power estimates eligible costs which, as they relate to acquisitions, may not be finalized until the allocation of the purchase price to assets has been finalized. Southern Power applies the deferred method to ITCs, whereby the ITCs are recorded as a deferred credit and amortized to income tax expense over the life of the respective asset. Furthermore, the tax basis of the asset is reduced by 50% of the ITCs received, resulting in a net deferred tax asset. Southern Power has elected to recognize the tax benefit of this basis difference as a reduction to income tax expense in the year in which the plant reaches commercial operation. State ITCs are recognized as an income tax benefit in the period in which the credits are generated. In addition, certain projects are eligible for federal and state PTCs, which are recognized as an income tax benefit based on KWH production. Federal ITCs and PTCs, as well as state ITCs and other state tax credits available to reduce income taxes payable, were not fully utilized in 2022 and will be carried forward and utilized in future years. In addition, Southern Company is expected to have various state net operating loss (NOL) carryforwards for certain of its subsidiaries, including Mississippi Power and Southern Power, which would result in income tax benefits in the future, if utilized. See Note 10 under "Current and Deferred Income Taxes – Tax Credit Carryforwards" and " – Net Operating Loss Carryforwards" for additional information. The Registrants recognize tax positions that are "more likely than not" of being sustained upon examination by the appropriate taxing authorities. See Note 10 under "Unrecognized Tax Benefits" for additional information. Other Taxes Taxes imposed on and collected from customers on behalf of governmental agencies are presented net on the Registrants' statements of income and are excluded from the transaction price in determining the revenue related to contracts with a customer.
Allowance for Funds Used During Construction and Interest Capitalized	Allowance for Funds Used During Construction and Interest Capitalized The traditional electric operating companies and the natural gas distribution utilities record AFUDC, which represents the estimated debt and equity costs of capital funds that are necessary to finance the construction of new regulated facilities. While cash is not realized currently, AFUDC increases the revenue requirement and is recovered over the service life of the asset through a higher rate base and higher depreciation. The equity component of AFUDC is not taxable. Interest related to financing the construction of new facilities at Southern Power and new facilities not included in the traditional electric operating companies' and Southern Company Gas' regulated rates is capitalized in accordance with standard interest capitalization requirements.
Impairment of Long-Lived Assets	Impairment of Long-Lived AssetsThe Registrants evaluate long-lived assets and finite-lived intangible assets for impairment when events or changes in circumstances indicate that the carrying amount of such assets may not be recoverable. The determination of whether an impairment has occurred is based on either a specific regulatory disallowance, a sales transaction price that is less than the asset group's carrying amount, or an estimate of undiscounted future cash flows attributable to the asset group, as compared with the carrying amount of the assets. If an impairment has occurred, the amount of the impairment recognized is determined by either the amount of regulatory disallowance or by estimating the fair value of the assets and recording a loss if the carrying amount is greater than the fair value. For assets identified as held for sale, the carrying amount is compared to the estimated fair value less the cost to sell in order to determine if an impairment loss is required. Until the assets are disposed of, their estimated fair value is re-evaluated when circumstances or events change.
Goodwill and Other Intangible Assets and Liabilities	Goodwill and Other Intangible Assets and Liabilities Southern Power's intangible assets consist primarily of certain PPAs acquired, which are amortized over the term of the respective PPA. Southern Company Gas' goodwill and other intangible assets and liabilities primarily relate to its 2016 acquisition by Southern Company. In addition to these items, Southern Company's goodwill and other intangible assets also relate to its 2016 acquisition of PowerSecure. For its 2022 and 2020 annual impairment tests, Southern Company Gas management performed the qualitative assessment and determined that it was more likely than not that the fair value of all of its reporting units with goodwill exceeded their carrying amounts, and therefore no quantitative assessment was required. For its 2021 annual impairment test, Southern Company Gas management performed the quantitative assessment and confirmed that the fair values of all of its reporting units with goodwill exceeded their carrying amounts. For its 2021 and 2020 annual impairment tests, PowerSecure management performed the quantitative assessment, which resulted in the fair value of PowerSecure exceeding its carrying amount. For its 2022 annual impairment test, PowerSecure management performed the quantitative assessment, which resulted in the fair value of PowerSecure being lower than its carrying amount. The fair value was estimated using a discounted cash flow analysis. The decline in fair value primarily resulted from declining macroeconomic conditions, reducing sales growth and estimated cash flows. As a result, a goodwill impairment of $119 million was recorded in the fourth quarter 2022. The worldwide disruptions in supply chain, reduced labor availability and productivity, and reduced economic activity in the United States have had a variety of adverse impacts on Southern Company and its subsidiaries, including PowerSecure. If these factors continue to negatively affect the operating results of PowerSecure, all or a portion of its remaining goodwill of $144 million may become impaired.
Acquisition Accounting	Acquisition Accounting At the time of an acquisition, management will assess whether acquired assets and activities meet the definition of a business. Acquisitions that meet the definition of a business are accounted for under the acquisition method, and operating results from the date of acquisition are included in the acquiring entity's financial statements. The purchase price, including any contingent consideration, is allocated based on the fair value of the identifiable assets acquired and liabilities assumed (including any intangible assets). Assets acquired that do not meet the definition of a business are accounted for as an asset acquisition. The purchase price of each asset acquisition is allocated based on the relative fair value of assets acquired. Determining the fair value of assets acquired and liabilities assumed requires management judgment and management may engage independent valuation experts to assist in this process. Fair values are determined by using market participant assumptions and typically include the timing and amounts of future cash flows, incurred construction costs, the nature of acquired contracts, discount rates, power market prices, and expected asset lives. Any due diligence or transition costs incurred for potential or successful acquisitions are expensed as incurred.
Development Costs	Development Costs For Southern Power, development costs are capitalized once a project is probable of completion, primarily based on a review of its economics and operational feasibility, as well as the status of power off-take agreements and regulatory approvals, if applicable. Southern Power's capitalized development costs are included in CWIP on the balance sheets. All of Southern Power's development costs incurred prior to the determination that a project is probable of completion are expensed as incurred and included in other operations and maintenance expense in the statements of income. If it is determined that a project is no longer probable of completion, any of Southern Power's capitalized development costs are expensed and included in other operations and maintenance expense in the statements of income.
Long-Term Service Agreements	Long-Term Service Agreements The traditional electric operating companies and Southern Power have entered into LTSAs for the purpose of securing maintenance support for certain of their generating facilities. The LTSAs cover all planned inspections on the covered equipment, which generally includes the cost of all labor and materials. The LTSAs also obligate the counterparties to cover the costs of unplanned maintenance on the covered equipment subject to limits and scope specified in each contract. Payments made under the LTSAs for the performance of any planned inspections or unplanned capital maintenance are recorded in the statements of cash flows as investing activities. Receipts of major parts into materials and supplies inventory prior to planned inspections are treated as noncash transactions in the statements of cash flows. Any payments made prior to the work being performed are recorded as prepayments in other current assets and noncurrent assets on the balance sheets. At the time work is performed, an appropriate amount is accrued for future payments or transferred from the prepayment and recorded as property, plant, and equipment or expensed.
Transmission Receivables/Prepayments	Transmission Receivables/Prepayments As a result of Southern Power's acquisition and construction of generating facilities, Southern Power has transmission receivables and/or prepayments representing the portion of interconnection network and transmission upgrades that will be reimbursed to Southern Power. Upon completion of the related project, transmission costs are generally reimbursed by the interconnection provider within a five-year period and the receivable/prepayments are reduced as payments or services are received.
Cash, Cash Equivalents, and Restricted Cash	Cash, Cash Equivalents, and Restricted Cash For purposes of the financial statements, temporary cash investments are considered cash equivalents. Temporary cash investments are securities with original maturities of 90 days or less.
Storm Damage and Reliability Reserves	Storm Damage and Reliability ReservesEach traditional electric operating company maintains a reserve to cover or is allowed to defer and recover the cost of damages from major storms to its transmission and distribution lines and, for Mississippi Power, the cost of uninsured damages to its generation facilities and other property.
Materials and Supplies	Materials and Supplies Materials and supplies for the traditional electric operating companies generally includes the average cost of transmission, distribution, and generating plant materials. Materials and supplies for Southern Company Gas generally includes propane gas inventory, liquefied natural gas inventory, fleet fuel, and other materials and supplies. Materials and supplies for Southern Power generally includes the average cost of generating plant materials. Materials are recorded to inventory when purchased and then expensed or capitalized to property, plant, and equipment, as appropriate, at weighted average cost when installed. In addition, certain major parts are recorded as inventory when acquired and then capitalized at cost when installed to property, plant, and equipment.
Fuel Inventory	Fuel Inventory Fuel inventory for the traditional electric operating companies includes the average cost of coal, natural gas, oil, transportation, and emissions allowances. Fuel inventory for Southern Power, which is included in other current assets, includes the average cost of oil, natural gas, and emissions allowances. Fuel is recorded to inventory when purchased and then expensed, at weighted average cost, as used. Emissions allowances granted by the EPA are included in inventory at zero cost. The traditional electric operating companies recover fuel expense through fuel cost recovery rates approved by each state PSC or, for wholesale rates, the FERC.
Natural Gas for Sale	Natural Gas for Sale With the exception of Nicor Gas, Southern Company Gas records natural gas inventories on a WACOG basis. In Georgia's deregulated, competitive environment, Marketers sell natural gas to firm end-use customers at market-based prices. On a monthly basis, Atlanta Gas Light assigns to Marketers the majority of the pipeline storage services that it has under contract, along with a corresponding amount of inventory. Atlanta Gas Light retains and manages a portion of its pipeline storage assets and related natural gas inventories for system balancing and to serve system demand. Nicor Gas' natural gas inventory is carried at cost on a LIFO basis. Inventory decrements occurring during the year that are restored prior to year end are charged to cost of natural gas at the estimated annual replacement cost. Inventory decrements that are not restored prior to year end are charged to cost of natural gas at the actual LIFO cost of the inventory layers liquidated. The cost of natural gas, including inventory costs, is recovered from customers under a purchased gas recovery mechanism adjusted for differences between actual costs and amounts billed; therefore, LIFO liquidations have no impact on Southern Company's or Southern Company Gas' net income. At December 31, 2022, the Nicor Gas LIFO inventory balance wa s $170 million. Based on the average cost of gas purchased in December 2022, the estimated replacement cost of Nicor Gas' inventory at December 31, 2022 was $613 million.
Provision for Uncollectible Accounts	Provision for Uncollectible Accounts The customers of the traditional electric operating companies and the natural gas distribution utilities are billed monthly. For the majority of receivables, a provision for uncollectible accounts is established based on historical collection experience and other factors. For the remaining receivables, if the company is aware of a specific customer's inability to pay, a provision for uncollectible accounts is recorded to reduce the receivable balance to the amount reasonably expected to be collected. If circumstances change, the estimate of the recoverability of accounts receivable could change as well. Circumstances that could affect this estimate include, but are not limited to, customer credit issues, customer deposits, and general economic conditions. Customers' accounts are written off once they are deemed to be uncollectible. For all periods presented, uncollectible accounts averaged less than 1% of revenues for each Registrant. Credit risk exposure at Nicor Gas is mitigated by a bad debt rider approved by the Illinois Commission. The bad debt rider provides for the recovery from (or refund to) customers of the difference between Nicor Gas' actual bad debt experience on an annual basis and the benchmark bad debt expense used to establish its base rates for the respective year.
Concentration of Credit Risk	Concentration of Credit Risk Concentration of credit risk occurs at Atlanta Gas Light for amounts billed for services and other costs to its customers, which consist of 14 Marketers in Georgia (including SouthStar). The credit risk exposure to the Marketers varies seasonally, with the lowest exposure in the non-peak summer months and the highest exposure in the peak winter months. Marketers are responsible
Financial Instruments	Financial Instruments The traditional electric operating companies and Southern Power use derivative financial instruments to limit exposure to fluctuations in interest rates, the prices of certain fuel purchases, electricity purchases and sales, and occasionally foreign currency exchange rates. Southern Company Gas uses derivative financial instruments to limit exposure to fluctuations in natural gas prices, weather, interest rates, and commodity prices. All derivative financial instruments are recognized as either assets or liabilities on the balance sheets (included in "Other" or shown separately as "Risk Management Activities") and are measured at fair value. See Note 13 for additional information regarding fair value. Substantially all of the traditional electric operating companies' and Southern Power's bulk energy purchases and sales contracts that meet the definition of a derivative are excluded from fair value accounting requirements because they qualify for the "normal" scope exception, and are accounted for under the accrual method. Derivative contracts that qualify as cash flow hedges of anticipated transactions or are recoverable through the traditional electric operating companies' and the natural gas distribution utilities' fuel-hedging programs result in the deferral of related gains and losses in AOCI or regulatory assets and liabilities, respectively, until the hedged transactions occur. Other derivative contracts that qualify as fair value hedges are marked to market through current period income and are recorded on a net basis in the statements of income. Cash flows from derivatives are classified on the statements of cash flows in the same category as the hedged item. See Note 14 for additional information regarding derivatives. The Registrants offset fair value amounts recognized for multiple derivative instruments executed with the same counterparty under netting arrangements. The Registrants had no outstanding collateral repayment obligations or rights to reclaim collateral arising from derivative instruments recognized at December 31, 2022. The Registrants are exposed to potential losses related to financial instruments in the event of counterparties' nonperformance. The Registrants have established risk management policies and controls to determine and monitor the creditworthiness of counterparties in order to mitigate their exposure to counterparty credit risk. Southern Company Gas Southern Company Gas enters into weather derivative contracts as economic hedges of natural gas revenues in the event of warmer-than-normal weather in the Heating Season. Exchange-traded options are carried at fair value, with changes reflected in natural gas revenues. Non-exchange-traded options are accounted for using the intrinsic value method. Changes in the intrinsic value for non-exchange-traded contracts are also reflected in natural gas revenues in the statements of income. Southern Company Gas enters into transactions to secure transportation capacity between delivery points in order to serve its customers and various markets. NYMEX futures and OTC contracts are used to capture the price differential or spread between the locations served by the capacity to substantially protect the natural gas revenues that will ultimately be realized when the physical flow of natural gas between delivery points occurs. These contracts generally meet the definition of derivatives and are carried at fair value on the balance sheets, with changes in fair value included in earnings in the period of change. These contracts are not designated as hedges for accounting purposes. The purchase, transportation, storage, and sale of natural gas are accounted for on a weighted average cost or accrual basis, as appropriate, rather than on the fair value basis utilized for the derivatives used to mitigate the natural gas price risk associated with the storage and transportation portfolio. Monthly demand charges are incurred for the contracted storage and transportation capacity and payments associated with asset management agreements, and these demand charges and payments are recognized on the statements of income in the period they are incurred. This difference in accounting methods can result in volatility in reported earnings, even though the economic margin is substantially unchanged from the dates the transactions were consummated. The Registrants are exposed to market risks, including commodity price risk, interest rate risk, weather risk, and occasionally foreign currency exchange rate risk. To manage the volatility attributable to these exposures, each company nets its exposures, where possible, to take advantage of natural offsets and enters into various derivative transactions for the remaining exposures pursuant to each company's policies in areas such as counterparty exposure and risk management practices. Prior to the sale of Sequent on July 1, 2021, Southern Company Gas' wholesale gas operations used various contracts in its commercial activities that generally met the definition of derivatives. For the traditional electric operating companies, Southern Power, and Southern Company Gas' other businesses, each company's policy is that derivatives are to be used primarily for hedging purposes and mandates strict adherence to all applicable risk management policies. Derivative positions are monitored using techniques including, but not limited to, market valuation, value at risk, stress testing, and sensitivity analysis. Derivative instruments are recognized at fair value in the balance sheets as either assets or liabilities and are presented on a net basis. See Note 13 for additional fair value information. In the statements of cash flows, any cash impacts of settled energy-related and interest rate derivatives are recorded as operating activities. Any cash impacts of settled foreign currency derivatives are classified as operating or financing activities to correspond with the classification of the hedged interest or principal, respectively. See Note 1 under "Financial Instruments" for additional information. See Note 15 under "Southern Company Gas" for additional information regarding the sale of Sequent. Energy-Related Derivatives The Subsidiary Registrants enter into energy-related derivatives to hedge exposures to electricity, natural gas, and other fuel price changes. However, due to cost-based rate regulations and other various cost recovery mechanisms, the traditional electric operating companies and the natural gas distribution utilities have limited exposure to market volatility in energy-related commodity prices. Each of the traditional electric operating companies and certain of the natural gas distribution utilities of Southern Company Gas manage fuel-hedging programs, implemented per the guidelines of their respective state PSCs or other applicable state regulatory agencies, through the use of financial derivative contracts, which are expected to continue to mitigate price volatility. The traditional electric operating companies (with respect to wholesale generating capacity) and Southern Power have limited exposure to market volatility in energy-related commodity prices because their long-term sales contracts shift substantially all fuel cost responsibility to the purchaser. However, the traditional electric operating companies and Southern Power may be exposed to market volatility in energy-related commodity prices to the extent any uncontracted capacity is used to sell electricity. Southern Company Gas retains exposure to price changes that can, in a volatile energy market, be material and can adversely affect its results of operations. Southern Company Gas also enters into weather derivative contracts as economic hedges in the event of warmer-than-normal weather. Exchange-traded options are carried at fair value, with changes reflected in operating revenues. Non-exchange-traded options are accounted for using the intrinsic value method. Changes in the intrinsic value for non-exchange-traded contracts are reflected in operating revenues. Energy-related derivative contracts are accounted for under one of three methods: • Regulatory Hedges – Energy-related derivative contracts designated as regulatory hedges relate primarily to the traditional electric operating companies' and the natural gas distribution utilities' fuel-hedging programs, where gains and losses are initially recorded as regulatory liabilities and assets, respectively, and then are included in fuel expense as the underlying fuel is used in operations and ultimately recovered through an approved cost recovery mechanism. • Cash Flow Hedges – Gains and losses on energy-related derivatives designated as cash flow hedges (which are mainly used to hedge anticipated purchases and sales) are initially deferred in AOCI before being recognized in the statements of income in the same period and in the same income statement line item as the earnings effect of the hedged transactions. • Not Designated – Gains and losses on energy-related derivative contracts that are not designated or fail to qualify as hedges are recognized in the statements of income as incurred. Some energy-related derivative contracts require physical delivery as opposed to financial settlement, and this type of derivative is both common and prevalent within the electric and natural gas industries. When an energy-related derivative contract is settled physically, any cumulative unrealized gain or loss is reversed and the contract price is recognized in the respective line item representing the actual price of the underlying goods being delivered. Interest Rate Derivatives Southern Company and certain subsidiaries may enter into interest rate derivatives to hedge exposure to changes in interest rates. Derivatives related to existing variable rate securities or forecasted transactions are accounted for as cash flow hedges where the derivatives' fair value gains or losses are recorded in OCI and are reclassified into earnings at the same time and presented on the same income statement line item as the earnings effect of the hedged transactions. Derivatives related to existing fixed rate securities are accounted for as fair value hedges, where the derivatives' fair value gains or losses and hedged items' fair value gains or losses are both recorded directly to earnings on the same income statement line item. Fair value gains or losses on derivatives that are not designated or fail to qualify as hedges are recognized in the statements of income as incurred. Foreign Currency Derivatives Southern Company and certain subsidiaries, including Southern Power, may enter into foreign currency derivatives to hedge exposure to changes in foreign currency exchange rates, such as that arising from the issuance of debt denominated in a currency other than U.S. dollars. Derivatives related to forecasted transactions are accounted for as cash flow hedges where the derivatives' fair value gains or losses are recorded in OCI and are reclassified into earnings at the same time and on the same income statement line as the earnings effect of the hedged transactions, including foreign currency gains or losses arising from changes in the U.S. currency exchange rates. Derivatives related to existing fixed rate securities are accounted for as fair value hedges, where the derivatives' fair value gains or losses and hedged items' fair value gains or losses are both recorded directly to earnings on the same income statement line item, including foreign currency gains or losses arising from changes in the U.S. currency exchange rates. Southern Company has elected to exclude the cross-currency basis spread from the assessment of effectiveness in the fair value hedges of its foreign currency risk and record any difference between the change in the fair value of the excluded components and the amounts recognized in earnings as a component of OCI.
Comprehensive Income	Comprehensive Income The objective of comprehensive income is to report a measure of all changes in common stock equity of an enterprise that result from transactions and other economic events of the period other than transactions with owners. Comprehensive income consists of net income attributable to the Registrant, changes in the fair value of qualifying cash flow hedges, and reclassifications for amounts included in net income. Comprehensive income also consists of certain changes in pension and other postretirement benefit plans for Southern Company, Southern Power, and Southern Company Gas.
Variable Interest Entities	Variable Interest Entities The Registrants may hold ownership interests in a number of business ventures with varying ownership structures. Partnership interests and other variable interests are evaluated to determine if each entity is a VIE. The primary beneficiary of a VIE is required to consolidate the VIE when it has both the power to direct the activities of the VIE that most significantly impact the VIE's economic performance and the obligation to absorb losses or the right to receive benefits from the VIE that could potentially be significant to the VIE. See Note 7 for additional information regarding VIEs.
Asset Retirement Obligations	AROs are computed as the present value of the estimated costs for an asset's future retirement and are recorded in the period in which the liability is incurred. The estimated costs are capitalized as part of the related long-lived asset and depreciated over the asset's useful life. In the absence of quoted market prices, AROs are estimated using present value techniques in which estimates of future cash outlays associated with the asset retirements are discounted using a credit-adjusted risk-free rate. Estimates of the timing and amounts of future cash outlays are based on projections of when and how the assets will be retired and the cost of future removal activities. Each traditional electric operating company and natural gas distribution utility has received accounting guidance from its state PSC or applicable state regulatory agency allowing the continued accrual or recovery of other retirement costs for long-lived assets that it does not have a legal obligation to retire. Accordingly, the accumulated removal costs for these obligations are reflected in the balance sheets as regulatory liabilities and amounts to be recovered are reflected in the balance sheets as regulatory assets. The ARO liabilities for the traditional electric operating companies primarily relate to facilities that are subject to the CCR Rule and the related state rules, principally ash ponds. In addition, Alabama Power and Georgia Power have retirement obligations related to the decommissioning of nuclear facilities (Alabama Power's Plant Farley and Georgia Power's ownership interests in Plant Hatch and Plant Vogtle Units 1 and 2). See "Nuclear Decommissioning" herein for additional information. Other significant AROs include various landfill sites and asbestos removal for Alabama Power, Georgia Power, and Mississippi Power and gypsum cells and mine reclamation for Mississippi Power. The ARO liability for Southern Power primarily relates to its solar and wind facilities, which are located on long-term land leases requiring the restoration of land at the end of the lease. The traditional electric operating companies and Southern Company Gas also have identified other retirement obligations, such as obligations related to certain electric transmission and distribution facilities, certain asbestos-containing material within long-term assets not subject to ongoing repair and maintenance activities, certain wireless communication towers, the disposal of polychlorinated biphenyls in certain transformers, leasehold improvements, equipment on customer property, and property associated with the Southern Company system's rail lines and natural gas pipelines. However, liabilities for the removal of these assets have not been recorded because the settlement timing for certain retirement obligations related to these assets is indeterminable and, therefore, the fair value of the retirement obligations cannot be reasonably estimated. A liability for these retirement obligations will be recognized when sufficient information becomes available to support a reasonable estimation of the ARO. Southern Company and the traditional electric operating companies will continue to recognize in their respective statements of income allowed removal costs in accordance with regulatory treatment. Any differences between costs recognized in accordance with accounting standards related to asset retirement and environmental obligations and those reflected in rates are recognized as either a regulatory asset or liability in the balance sheets as ordered by the various state PSCs.
Nuclear Decommissioning	Nuclear Decommissioning The NRC requires licensees of commercial nuclear power reactors to establish a plan for providing reasonable assurance of funds for future decommissioning. Alabama Power and Georgia Power have external trust funds (Funds) to comply with the NRC's regulations. Use of the Funds is restricted to nuclear decommissioning activities. The Funds are managed and invested in accordance with applicable requirements of various regulatory bodies, including the NRC, the FERC, and state PSCs, as well as the IRS. While Alabama Power and Georgia Power are allowed to prescribe an overall investment policy to the Funds' managers, neither Southern Company nor its subsidiaries or affiliates are allowed to engage in the day-to-day management of the Funds or to mandate individual investment decisions. Day-to-day management of the investments in the Funds is delegated to unrelated third-party managers with oversight by the management of Alabama Power and Georgia Power. The Funds' managers are authorized, within certain investment guidelines, to actively buy and sell securities at their own discretion in order to maximize the return on the Funds' investments. The Funds are invested in a tax-efficient manner in a diversified mix of equity and fixed income securities and are reported as trading securities. Alabama Power and Georgia Power record the investment securities held in the Funds at fair value, as disclosed in Note 13, as management believes that fair value best represents the nature of the Funds. Gains and losses, whether realized or unrealized, are recorded in the regulatory liability for AROs in the balance sheets and are not included in net income or OCI. Fair value adjustments and realized gains and losses are determined on a specific identification basis.
Fair Value Measurement	Fair value measurements are based on inputs of observable and unobservable market data that a market participant would use in pricing the asset or liability. The use of observable inputs is maximized where available and the use of unobservable inputs is minimized for fair value measurement and reflects a three-tier fair value hierarchy that prioritizes inputs to valuation techniques used for fair value measurement. • Level 1 consists of observable market data in an active market for identical assets or liabilities. • Level 2 consists of observable market data, other than that included in Level 1, that is either directly or indirectly observable. • Level 3 consists of unobservable market data. The input may reflect the assumptions of each Registrant of what a market participant would use in pricing an asset or liability. If there is little available market data, then each Registrant's own assumptions are the best available information. In the case of multiple inputs being used in a fair value measurement, the lowest level input that is significant to the fair value measurement represents the level in the fair value hierarchy in which the fair value measurement is reported. Valuation Methodologies The energy-related derivatives primarily consist of exchange-traded and over-the-counter financial products for natural gas and physical power products, including, from time to time, basis swaps. These are standard products used within the energy industry and are valued using the market approach. The inputs used are mainly from observable market sources, such as forward natural gas prices, power prices, implied volatility, and overnight index swap interest rates. Interest rate derivatives are also standard over-the-counter products that are valued using observable market data and assumptions commonly used by market participants. The fair value of interest rate derivatives reflects the net present value of expected payments and receipts under the swap agreement based on the market's expectation of future interest rates. Additional inputs to the net present value calculation may include the contract terms, counterparty credit risk, and occasionally, implied volatility of interest rate options. The fair value of cross-currency swaps reflects the net present value of expected payments and receipts under the swap agreement based on the market's expectation of future foreign currency exchange rates. Additional inputs to the net present value calculation may include the contract terms, counterparty credit risk, and discount rates. The interest rate derivatives and cross-currency swaps are categorized as Level 2 under Fair Value Measurements as these inputs are based on observable data and valuations of similar instruments. See Note 14 for additional information on how these derivatives are used. For fair value measurements of the investments within the nuclear decommissioning trusts and the non-qualified deferred compensation trusts, external pricing vendors are designated for each asset class with each security specifically assigned a primary pricing source. For investments held within commingled funds, fair value is determined at the end of each business day through the net asset value, which is established by obtaining the underlying securities' individual prices from the primary pricing source. A market price secured from the primary source vendor is then evaluated by management in its valuation of the assets within the trusts. As a general approach, fixed income market pricing vendors gather market data (including indices and market research reports) and integrate relative credit information, observed market movements, and sector news into proprietary pricing models, pricing systems, and mathematical tools. Dealer quotes and other market information, including live trading levels and pricing analysts' judgments, are also obtained when available. The NRC requires licensees of commissioned nuclear power reactors to establish a plan for providing reasonable assurance of funds for future decommissioning. See Note 6 under "Nuclear Decommissioning" for additional information. Southern Power has contingent payment obligations related to certain acquisitions whereby it is primarily obligated to make generation-based payments to the seller, which commenced at the commercial operation of the respective facility and continue through 2026. The obligations are categorized as Level 3 under Fair Value Measurements as the fair value is determined using significant unobservable inputs for the forecasted facility generation in MW-hours, as well as other inputs such as a fixed dollar amount per MW-hour, and a discount rate. The fair value of contingent consideration reflects the net present value of expected payments and any periodic change arising from forecasted generation is expected to be immaterial. Southern Power also has payment obligations through 2040 whereby it must reimburse the transmission owners for interconnection facilities and network upgrades constructed to support connection of a Southern Power generating facility to the transmission system. The obligations are categorized as Level 2 under Fair Value Measurements as the fair value is determined using observable inputs for the contracted amounts and reimbursement period, as well as a discount rate. The fair value of the obligations reflects the net present value of expected payments. "Other investments" include investments traded in the open market that have maturities greater than 90 days, which are categorized as Level 2 under Fair Value Measurements and are comprised of corporate bonds, bank certificates of deposit, treasury bonds, and/or agency bonds.

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Tables)	12 Months Ended
	Dec. 31, 2022
Accounting Policies [Abstract]
Schedule of costs for affiliate transactions	Costs for these services from SCS in 2022, 2021, and 2020 were as follows: Alabama Georgia Mississippi Southern Southern Company Gas (in millions) 2022 $ 549 $ 762 $ 115 $ 86 $ 262 2021 504 663 120 89 239 2020 478 639 149 87 237 Mississippi Southern (in millions) 2022 $ 4 $ 29 2021 9 15 2020 4 8 Alabama Georgia Southern Southern Company Gas (in millions) 2022 $ 18 $ 99 $ 37 $ 27 2021 14 108 31 29 2020 15 108 29 29 2022 2021 2020 Alabama Power 2.7 % 2.7 % 2.6 % Georgia Power 3.3 % 3.3 % 3.0 % Mississippi Power 3.4 % 3.6 % 3.7 % Southern Company Gas 2.7 % 2.8 % 2.8 %
Schedule of total AFUDC and interest capitalized	Total AFUDC and interest capitalized for the Registrants in 2022, 2021, and 2020 was as follows: Southern Company Alabama Georgia (*) Mississippi Southern Southern Company Gas (in millions) 2022 $ 327 $ 90 $ 213 $ — $ — $ 24 2021 282 68 190 — 6 18 2020 230 61 138 1 11 18 (*) See Note 2 under "Georgia Power – Nuclear Construction" for information on the inclusion of a portion of construction costs related to Plant Vogtle Units 3 and 4 in Georgia Power's rate base.
Schedule of average AFUDC composite rates	The average AFUDC composite rates for 2022, 2021, and 2020 for the traditional electric operating companies and the natural gas distribution utilities were as follows: 2022 2021 2020 Alabama Power 7.9 % 7.9 % 8.1 % Georgia Power (*) 7.3 % 7.2 % 6.9 % Mississippi Power 5.3 % 2.5 % 5.4 % Southern Company Gas: Atlanta Gas Light 7.6 % 7.7 % 7.7 % Chattanooga Gas 7.1 % 7.1 % 7.1 % Nicor Gas 2.0 % 0.1 % 0.7 % (*) Excludes AFUDC related to the construction of Plant Vogtle Units 3 and 4. See Note 2 under "Georgia Power – Nuclear Construction" for additional information.
Schedule of goodwill balances	At December 31, 2022 and 2021, goodwill was as follows: At December 31, 2022 At December 31, 2021 (in millions) Southern Company $ 5,161 $ 5,280 Southern Company Gas: Gas distribution operations $ 4,034 $ 4,034 Gas marketing services 981 981 Southern Company Gas total $ 5,015 $ 5,015
Schedule of intangible assets subject to amortization	At December 31, 2022 and 2021, other intangible assets were as follows: At December 31, 2022 At December 31, 2021 Gross Carrying Amount Accumulated Amortization Other Gross Carrying Amount Accumulated Amortization Other (in millions) (in millions) Southern Company Subject to amortization: Customer relationships $ 212 $ (162) $ 50 $ 212 $ (150) $ 62 Trade names 64 (44) 20 64 (38) 26 PPA fair value adjustments 390 (129) 261 390 (109) 281 Other 5 (5) — 11 (10) 1 Total subject to amortization $ 671 $ (340) $ 331 $ 677 $ (307) $ 370 Not subject to amortization: FCC licenses 75 — 75 75 — 75 Total other intangible assets $ 746 $ (340) $ 406 $ 752 $ (307) $ 445 Southern Power (*) PPA fair value adjustments $ 390 $ (129) $ 261 $ 390 $ (109) $ 281 Southern Company Gas (*) Gas marketing services Customer relationships $ 156 $ (139) $ 17 $ 156 $ (130) $ 26 Trade names 26 (17) 9 26 (15) 11 Total other intangible assets $ 182 $ (156) $ 26 $ 182 $ (145) $ 37 (*) All subject to amortization.
Schedule of intangible assets not subject to amortization	At December 31, 2022 and 2021, other intangible assets were as follows: At December 31, 2022 At December 31, 2021 Gross Carrying Amount Accumulated Amortization Other Gross Carrying Amount Accumulated Amortization Other (in millions) (in millions) Southern Company Subject to amortization: Customer relationships $ 212 $ (162) $ 50 $ 212 $ (150) $ 62 Trade names 64 (44) 20 64 (38) 26 PPA fair value adjustments 390 (129) 261 390 (109) 281 Other 5 (5) — 11 (10) 1 Total subject to amortization $ 671 $ (340) $ 331 $ 677 $ (307) $ 370 Not subject to amortization: FCC licenses 75 — 75 75 — 75 Total other intangible assets $ 746 $ (340) $ 406 $ 752 $ (307) $ 445 Southern Power (*) PPA fair value adjustments $ 390 $ (129) $ 261 $ 390 $ (109) $ 281 Southern Company Gas (*) Gas marketing services Customer relationships $ 156 $ (139) $ 17 $ 156 $ (130) $ 26 Trade names 26 (17) 9 26 (15) 11 Total other intangible assets $ 182 $ (156) $ 26 $ 182 $ (145) $ 37 (*) All subject to amortization.
Schedule of amortization associated with other intangible assets	Amortization associated with other intangible assets in 2022, 2021, and 2020 was as follows: 2022 2021 2020 (in millions) Southern Company (a) $ 39 $ 44 $ 49 Southern Power (b) 20 20 20 Southern Company Gas: Gas marketing services $ 11 $ 15 $ 17 Wholesale gas services (b) — — 2 Southern Company Gas total $ 11 $ 15 $ 19 (a) Includes $20 million, $20 million, and $22 million in 2022, 2021, and 2020, respectively, recorded as a reduction to operating revenues. (b) Recorded as a reduction to operating revenues.
Schedule of estimated future amortization of other intangible assets	At December 31, 2022, the estimated amortization associated with other intangible assets for the next five years is as follows: 2023 2024 2025 2026 2027 (in millions) Southern Company $ 36 $ 35 $ 31 $ 26 $ 23 Southern Power 20 20 20 20 20 Southern Company Gas 9 8 6 3 —
Schedule of cash, cash equivalents, and restricted cash	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets that total to the amount shown in the statements of cash flows for the applicable Registrants: Southern Georgia Southern Southern December 31, 2022 2021 2022 2022 2021 2022 2021 (in millions) (in millions) (in millions) Cash and cash equivalents $ 1,917 $ 1,798 $ 364 $ 131 $ 107 $ 81 $ 45 Restricted cash (a) : Other current assets 62 2 60 — — 2 2 Other deferred charges and assets 58 29 56 3 29 — — Total cash, cash equivalents, and restricted cash (b) $ 2,037 $ 1,829 $ 480 $ 133 $ 135 $ 83 $ 48 (a) For Georgia Power, reflects proceeds from the issuance of solid waste disposal facility revenue bonds. See Note 8 under "Long-term Debt" for additional information. Georgia Power did not have any restricted cash at December 31, 2021. For Southern Power, reflects $3 million and $10 million at December 31, 2022 and 2021, respectively, held to fund estimated construction completion costs at the Deuel Harvest wind facility and $19 million at December 31, 2021 related to tax equity contributions restricted until the Garland battery energy storage facility achieved final contracted capacity. See Note 15 under "Southern Power" for additional information. For Southern Company Gas, reflects collateral for workers' compensation, life insurance, and long-term disability insurance. (b) Total may not add due to rounding.
Reconciliation of restricted cash and cash equivalents	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the balance sheets that total to the amount shown in the statements of cash flows for the applicable Registrants: Southern Georgia Southern Southern December 31, 2022 2021 2022 2022 2021 2022 2021 (in millions) (in millions) (in millions) Cash and cash equivalents $ 1,917 $ 1,798 $ 364 $ 131 $ 107 $ 81 $ 45 Restricted cash (a) : Other current assets 62 2 60 — — 2 2 Other deferred charges and assets 58 29 56 3 29 — — Total cash, cash equivalents, and restricted cash (b) $ 2,037 $ 1,829 $ 480 $ 133 $ 135 $ 83 $ 48 (a) For Georgia Power, reflects proceeds from the issuance of solid waste disposal facility revenue bonds. See Note 8 under "Long-term Debt" for additional information. Georgia Power did not have any restricted cash at December 31, 2021. For Southern Power, reflects $3 million and $10 million at December 31, 2022 and 2021, respectively, held to fund estimated construction completion costs at the Deuel Harvest wind facility and $19 million at December 31, 2021 related to tax equity contributions restricted until the Garland battery energy storage facility achieved final contracted capacity. See Note 15 under "Southern Power" for additional information. For Southern Company Gas, reflects collateral for workers' compensation, life insurance, and long-term disability insurance. (b) Total may not add due to rounding.
Schedule of storm damage reserves	In accordance with their respective state PSC orders, the traditional electric operating companies accrued the following amounts related to storm damage recovery in 2022, 2021, and 2020: Southern Company (*) Alabama Georgia Mississippi Power (*) (in millions) 2022 $ 239 $ 19 $ 213 $ 7 2021 286 75 213 (2) 2020 326 112 213 1 (*) Mississippi Power's net accrual includes carrying costs, as well as amortization of related excess deferred income tax benefits. Southern Alabama Mississippi (in millions) 2022 $ 191 $ 166 $ 25
Schedule of AOCI (loss) balances, net of tax effects	AOCI (loss) balances, net of tax effects, for Southern Company, Southern Power, and Southern Company Gas were as follows: Qualifying Pension and Other Accumulated Other Comprehensive Income (Loss) (*) (in millions) Southern Company Balance at December 31, 2021 $ (162) $ (76) $ (237) Current period change 13 58 71 Balance at December 31, 2022 $ (149) $ (18) $ (167) Southern Power Balance at December 31, 2021 $ 1 $ (29) $ (27) Current period change (10) 20 10 Balance at December 31, 2022 $ (9) $ (9) $ (18) Southern Company Gas Balance at December 31, 2021 $ (14) $ 38 $ 24 Current period change (11) 18 7 Balance at December 31, 2022 $ (25) $ 56 $ 31 (*) May not add due to rounding.

REGULATORY MATTERS (Tables)

REGULATORY MATTERS (Tables)	12 Months Ended
	Dec. 31, 2022
Regulated Operations [Abstract]
Schedule of regulatory assets	Details of regulatory assets and (liabilities) reflected in the balance sheets at December 31, 2022 and 2021 are provided in the following tables: Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) At December 31, 2022 AROs (a)(u) $ 6,096 $ 1,971 $ 3,829 $ 242 $ — Retiree benefit plans (b)(u) 2,517 675 848 113 114 Remaining net book value of retired assets (c) 1,543 562 962 19 — Under recovered regulatory clause revenues (d) 953 788 — 31 134 Deferred income tax charges (e) 866 250 583 30 — Environmental remediation (f)(u) 294 — 25 — 269 Loss on reacquired debt (g) 257 38 213 5 1 Vacation pay (h)(u) 212 82 108 10 12 Regulatory clauses (i) 142 142 — — — Software and cloud computing costs (j) 111 46 59 — 6 Nuclear outage (k) 82 52 30 — — Long-term debt fair value adjustment (l) 69 — — — 69 Fuel-hedging (realized and unrealized) losses (m) 60 15 45 — — Storm damage (n) 44 — — 44 — Plant Daniel Units 3 and 4 (o) 27 — — 27 — Kemper County energy facility assets, net (p) 20 — — 20 — Other regulatory assets (q) 197 36 27 16 118 Deferred income tax credits (e) (5,251) (1,925) (2,244) (269) (788) Other cost of removal obligations (a) (1,430) 11 462 (196) (1,707) Storm/property damage reserves (r) (216) (97) (83) (36) — Reliability reserves (r) (191) (166) — (25) — Customer refunds (s) (183) (62) (121) — — Fuel-hedging (realized and unrealized) gains (m ) (83) (38) (21) (24) — Over recovered regulatory clause revenues (d) (64) — (38) — (26) Other regulatory liabilities (t) (239) (40) (21) (3) (93) Total regulatory assets (liabilities), net $ 5,833 $ 2,340 $ 4,663 $ 4 $ (1,891) Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) At December 31, 2021 AROs (a)(u) $ 5,685 $ 1,576 $ 3,866 $ 236 $ — Retiree benefit plans (b)(u) 2,998 747 962 145 95 Remaining net book value of retired assets (c) 1,050 574 455 21 — Deferred income tax charges (e) 829 240 555 31 — Under recovered regulatory clause revenues (d) 806 225 — 49 532 Environmental remediation (f)(u) 302 — 35 — 267 Loss on reacquired debt (g) 281 42 231 6 2 Vacation pay (h)(u) 207 81 102 10 14 Regulatory clauses (i) 142 142 — — — Storm damage (n) 97 — 48 49 — Long-term debt fair value adjustment (l) 79 — — — 79 Nuclear outage (k) 75 41 34 — — Software and cloud computing costs (j) 73 35 33 — 5 Kemper County energy facility assets, net (p) 35 — — 35 — Plant Daniel Units 3 and 4 (o) 28 — — 28 — Other regulatory assets (q) 168 38 29 7 94 Deferred income tax credits (e) (5,636) (1,968) (2,537) (288) (816) Other cost of removal obligations (a) (1,826) (192) 278 (195) (1,683) Customer refunds (s ) (189) (181) (8) — — Fuel-hedging (realized and unrealized) gains (m) (176) (50) (72) (54) — Storm/property damage reserves (r) (133) (103) — (30) — Over recovered regulatory clause revenues (d) (63) (1) (59) — (3) Other regulatory liabilities (t) (121) (29) (24) (4) (57) Total regulatory assets (liabilities), net $ 4,711 $ 1,217 $ 3,928 $ 46 $ (1,471) Unless otherwise noted, the following recovery and amortization periods for these regulatory assets and (liabilities) have been approved by the respective state PSC or regulatory agency: (a) AROs and other cost of removal obligations generally are recorded over the related property lives, which may range up to 53 years for Alabama Power, 57 years for Georgia Power, 55 years for Mississippi Power, and 80 years for Southern Company Gas. AROs and cost of removal obligations are settled and trued up following completion of the related activities. Alabama Power is recovering CCR ARO expenditures over a 38-year period ending in 2054 through Rate CNP Compliance. Effective January 1, 2023, Georgia Power is recovering CCR ARO expenditures over four-year periods through its ECCR tariff. Prior to 2023, expenditures were recovered over three-year periods. See "Georgia Power – Rate Plans" herein and Note 6 for additional information. (b) Recovered and amortized over the average remaining service period, which may range up to 13 years for Alabama Power, Georgia Power, and Mississippi Power and up to 14 years for Southern Company Gas. Southern Company's balances also include amounts at SCS and Southern Nuclear that are allocated to the applicable regulated utilities. See Note 11 for additional information. (c) Alabama Power : Primarily represents the net book value of Plant Gorgas Units 8, 9, and 10 ($492 million at December 31, 2022) being amortized over remaining periods not exceeding 15 years (through 2037). Balance at December 31, 2022 also includes approximately $42 million related to Plant Barry Unit 4 being amortized over the unit's remaining useful life (through 2034). See "Alabama Power – Environmental Accounting Order" herein for additional information. Georgia Power : Net book values of Plant Wansley Units 1 and 2 (totaling $562 million at December 31, 2022) are being amortized over a remaining period of eight years (through 2030) and net book values of Plant Hammond Units 1 through 4 and Plant Branch Units 3 and 4 (totaling $396 million at December 31, 2022) are being amortized over remaining periods of between one Mississippi Power : Represents net book value of certain environmental compliance assets at Plant Watson and Plant Greene County. The retail portion is being amortized over a 10-year period through 2030 and the wholesale portion is being amortized over a 14-year period through 2035. See "Mississippi Power – Environmental Compliance Overview Plan" herein for additional information. (d) Alabama Power : Balances are recorded monthly and expected to be recovered over periods of up to eight years, with the majority expected to be recovered within two years. See "Alabama Power – Rate CNP PPA," " – Rate CNP Compliance," and " – Rate ECR" herein for additional information. Georgia Power : Balances are recorded monthly and expected to be recovered or returned within two years. See "Georgia Power – Rate Plans" herein for additional information. Mississippi Power : At December 31, 2022, $12 million is being amortized over a three-year period ending in 2023 and the remaining $18 million is expected to be recovered through various rate recovery mechanisms over a period to be determined in future rate filings. See "Mississippi Power – Ad Valorem Tax Adjustment" herein for additional information. Southern Company Gas : Balances are recorded and recovered or amortized over periods generally not exceeding five years. In addition to natural gas cost recovery mechanisms, the natural gas distribution utilities have various other cost recovery mechanisms for the recovery of costs, including those related to infrastructure replacement programs. (e) Deferred income tax charges are recovered and deferred income tax credits are amortized over the related property lives, which may range up to 53 years for Alabama Power, 57 years for Georgia Power, 55 years for Mississippi Power, and 80 years for Southern Company Gas. See Note 10 for additional information. As a result of the Tax Reform Legislation, these accounts include certain deferred income tax assets and liabilities not subject to normalization, as described further below: Alabama Power : Related amounts at December 31, 2022 include excess federal deferred income tax liabilities that are being returned to customers through bill credits of up to approximately $318 million in 2023, as discussed under "Alabama Power – Excess Accumulated Deferred Income Tax Accounting Order" herein. The Alabama PSC will determine the treatment of any remaining excess federal accumulated deferred income taxes at a future date. Remaining amounts are being recovered and amortized ratably over the related property lives. Georgia Power : Related amounts at December 31, 2022 include $145 million of deferred income tax assets related to CWIP for Plant Vogtle Units 3 and 4, the recovery of which is expected to be determined in a future regulatory proceeding. Mississippi Power : Related amounts at December 31, 2022 include $33 million of retail deferred income tax liabilities generally being amortized over three years through 2025. Southern Company Gas : Related amounts at December 31, 2022 include $1 million of deferred income tax liabilities being amortized through 2024. See "Southern Company Gas – Rate Proceedings" herein for additional information. (f) Effective January 1, 2023, Georgia Power is recovering $5 million annually for environmental remediation under the 2022 ARP. Southern Company Gas' costs are recovered through environmental cost recovery mechanisms when the remediation work is performed. See Note 3 under "Environmental Remediation" for additional information. (g) Recovered over either the remaining life of the original issue or, if refinanced, over the remaining life of the new issue. At December 31, 2022, the remaining amortization periods do not exceed 25 years for Alabama Power, 30 years for Georgia Power, 19 years for Mississippi Power, and five years for Southern Company Gas. (h) Recorded as earned by employees and recovered as paid, generally within one year. Includes both vacation and banked holiday pay, if applicable. (i) Effective January 1, 2023, balance is being amortized through Rate RSE over a five-year period ending in 2027. (j) Represents certain deferred operations and maintenance costs associated with software and cloud computing projects. For Alabama Power, costs are amortized ratably over the life of the related software, which ranges up to 10 years. See "Alabama Power – Software Accounting Order" herein for additional information. For Georgia Power, costs incurred through 2022 will be amortized over five years starting in 2023 and the recovery period for all future costs will be determined in its next base rate case. For Southern Company Gas, costs began being amortized ratably in July 2022 over the life of the related software, which ranges up to 10 years. (k) Nuclear outage costs are deferred to a regulatory asset when incurred and amortized over a subsequent period of 18 months for Alabama Power and up to 24 months for Georgia Power. See Note 5 for additional information. (l) Recovered over the remaining lives of the original debt issuances at acquisition, which range up to 16 years at December 31, 2022. (m) Fuel-hedging assets and liabilities are recorded over the life of the underlying hedged purchase contracts. Upon final settlement, actual costs incurred are recovered through the applicable traditional electric operating company's fuel cost recovery mechanism. Purchase contracts generally do not exceed three and a half years for Alabama Power, three years for Georgia Power, and four years for Mississippi Power. (n) Mississippi Power's balance represents deferred storm costs associated with Hurricanes Ida and Zeta being recovered through PEP over an eight-year period through 2029. (o) Represents the difference between Mississippi Power's revenue requirement for Plant Daniel Units 3 and 4 under purchase accounting and operating lease accounting. At December 31, 2022, consists of the $18 million retail portion being amortized through 2039 over the remaining life of the related property and the $9 million wholesale portion being amortized through 2035. (p) Includes $26 million of regulatory assets and $6 million of regulatory liabilities at December 31, 2022. The retail portion includes $17 million of regulatory assets and $6 million of regulatory liabilities that are expected to be fully amortized by 2023 and 2025, respectively. The wholesale portion includes $10 million of regulatory assets that are expected to be fully amortized by 2035. (q) Comprised of numerous immaterial components with remaining amortization periods generally not exceeding 21 years for Alabama Power, 10 years for Georgia Power, 14 years for Mississippi Power, and 20 years for Southern Company Gas at December 31, 2022. (r) Utilized as related expenses are incurred. See "Alabama Power – Rate NDR" and " – Reliability Reserve Accounting Order," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" and " – Reliability Reserve Accounting Order" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. (s) Primarily includes approximately $62 million and $181 million at December 31, 2022 and 2021, respectively, for Alabama Power and $119 million and $5 million at December 31, 2022 and 2021, respectively, for Georgia Power as a result of each company exceeding its allowed retail return range. Georgia Power's balances also include immaterial amounts related to refunds for transmission service customers. See "Alabama Power – Rate RSE" and "Georgia Power – Rate Plans" herein for additional information. (t) Comprised of numerous immaterial components with remaining amortization periods generally not exceeding 11 years for Alabama Power, 10 years for Georgia Power, four years for Mississippi Power, and 20 years for Southern Company Gas at December 31, 2022. (u) Generally not earning a return as they are excluded from rate base or are offset in rate base by a corresponding asset or liability. The following table illustrates Southern Company Gas' authorized ratemaking amounts that are not recognized on its balance sheets. These amounts are primarily composed of an allowed equity rate of return on assets associated with certain regulatory infrastructure programs. These amounts will be recognized as revenues in Southern Company Gas' financial statements in the periods they are billable to customers, the majority of which will be recovered by 2025. December 31, 2022 December 31, 2021 (in millions) Atlanta Gas Light $ 35 $ 47 Virginia Natural Gas 10 10 Chattanooga Gas 2 4 Nicor Gas 3 — Total $ 50 $ 61
Schedule of regulatory liabilities	Details of regulatory assets and (liabilities) reflected in the balance sheets at December 31, 2022 and 2021 are provided in the following tables: Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) At December 31, 2022 AROs (a)(u) $ 6,096 $ 1,971 $ 3,829 $ 242 $ — Retiree benefit plans (b)(u) 2,517 675 848 113 114 Remaining net book value of retired assets (c) 1,543 562 962 19 — Under recovered regulatory clause revenues (d) 953 788 — 31 134 Deferred income tax charges (e) 866 250 583 30 — Environmental remediation (f)(u) 294 — 25 — 269 Loss on reacquired debt (g) 257 38 213 5 1 Vacation pay (h)(u) 212 82 108 10 12 Regulatory clauses (i) 142 142 — — — Software and cloud computing costs (j) 111 46 59 — 6 Nuclear outage (k) 82 52 30 — — Long-term debt fair value adjustment (l) 69 — — — 69 Fuel-hedging (realized and unrealized) losses (m) 60 15 45 — — Storm damage (n) 44 — — 44 — Plant Daniel Units 3 and 4 (o) 27 — — 27 — Kemper County energy facility assets, net (p) 20 — — 20 — Other regulatory assets (q) 197 36 27 16 118 Deferred income tax credits (e) (5,251) (1,925) (2,244) (269) (788) Other cost of removal obligations (a) (1,430) 11 462 (196) (1,707) Storm/property damage reserves (r) (216) (97) (83) (36) — Reliability reserves (r) (191) (166) — (25) — Customer refunds (s) (183) (62) (121) — — Fuel-hedging (realized and unrealized) gains (m ) (83) (38) (21) (24) — Over recovered regulatory clause revenues (d) (64) — (38) — (26) Other regulatory liabilities (t) (239) (40) (21) (3) (93) Total regulatory assets (liabilities), net $ 5,833 $ 2,340 $ 4,663 $ 4 $ (1,891) Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) At December 31, 2021 AROs (a)(u) $ 5,685 $ 1,576 $ 3,866 $ 236 $ — Retiree benefit plans (b)(u) 2,998 747 962 145 95 Remaining net book value of retired assets (c) 1,050 574 455 21 — Deferred income tax charges (e) 829 240 555 31 — Under recovered regulatory clause revenues (d) 806 225 — 49 532 Environmental remediation (f)(u) 302 — 35 — 267 Loss on reacquired debt (g) 281 42 231 6 2 Vacation pay (h)(u) 207 81 102 10 14 Regulatory clauses (i) 142 142 — — — Storm damage (n) 97 — 48 49 — Long-term debt fair value adjustment (l) 79 — — — 79 Nuclear outage (k) 75 41 34 — — Software and cloud computing costs (j) 73 35 33 — 5 Kemper County energy facility assets, net (p) 35 — — 35 — Plant Daniel Units 3 and 4 (o) 28 — — 28 — Other regulatory assets (q) 168 38 29 7 94 Deferred income tax credits (e) (5,636) (1,968) (2,537) (288) (816) Other cost of removal obligations (a) (1,826) (192) 278 (195) (1,683) Customer refunds (s ) (189) (181) (8) — — Fuel-hedging (realized and unrealized) gains (m) (176) (50) (72) (54) — Storm/property damage reserves (r) (133) (103) — (30) — Over recovered regulatory clause revenues (d) (63) (1) (59) — (3) Other regulatory liabilities (t) (121) (29) (24) (4) (57) Total regulatory assets (liabilities), net $ 4,711 $ 1,217 $ 3,928 $ 46 $ (1,471) Unless otherwise noted, the following recovery and amortization periods for these regulatory assets and (liabilities) have been approved by the respective state PSC or regulatory agency: (a) AROs and other cost of removal obligations generally are recorded over the related property lives, which may range up to 53 years for Alabama Power, 57 years for Georgia Power, 55 years for Mississippi Power, and 80 years for Southern Company Gas. AROs and cost of removal obligations are settled and trued up following completion of the related activities. Alabama Power is recovering CCR ARO expenditures over a 38-year period ending in 2054 through Rate CNP Compliance. Effective January 1, 2023, Georgia Power is recovering CCR ARO expenditures over four-year periods through its ECCR tariff. Prior to 2023, expenditures were recovered over three-year periods. See "Georgia Power – Rate Plans" herein and Note 6 for additional information. (b) Recovered and amortized over the average remaining service period, which may range up to 13 years for Alabama Power, Georgia Power, and Mississippi Power and up to 14 years for Southern Company Gas. Southern Company's balances also include amounts at SCS and Southern Nuclear that are allocated to the applicable regulated utilities. See Note 11 for additional information. (c) Alabama Power : Primarily represents the net book value of Plant Gorgas Units 8, 9, and 10 ($492 million at December 31, 2022) being amortized over remaining periods not exceeding 15 years (through 2037). Balance at December 31, 2022 also includes approximately $42 million related to Plant Barry Unit 4 being amortized over the unit's remaining useful life (through 2034). See "Alabama Power – Environmental Accounting Order" herein for additional information. Georgia Power : Net book values of Plant Wansley Units 1 and 2 (totaling $562 million at December 31, 2022) are being amortized over a remaining period of eight years (through 2030) and net book values of Plant Hammond Units 1 through 4 and Plant Branch Units 3 and 4 (totaling $396 million at December 31, 2022) are being amortized over remaining periods of between one Mississippi Power : Represents net book value of certain environmental compliance assets at Plant Watson and Plant Greene County. The retail portion is being amortized over a 10-year period through 2030 and the wholesale portion is being amortized over a 14-year period through 2035. See "Mississippi Power – Environmental Compliance Overview Plan" herein for additional information. (d) Alabama Power : Balances are recorded monthly and expected to be recovered over periods of up to eight years, with the majority expected to be recovered within two years. See "Alabama Power – Rate CNP PPA," " – Rate CNP Compliance," and " – Rate ECR" herein for additional information. Georgia Power : Balances are recorded monthly and expected to be recovered or returned within two years. See "Georgia Power – Rate Plans" herein for additional information. Mississippi Power : At December 31, 2022, $12 million is being amortized over a three-year period ending in 2023 and the remaining $18 million is expected to be recovered through various rate recovery mechanisms over a period to be determined in future rate filings. See "Mississippi Power – Ad Valorem Tax Adjustment" herein for additional information. Southern Company Gas : Balances are recorded and recovered or amortized over periods generally not exceeding five years. In addition to natural gas cost recovery mechanisms, the natural gas distribution utilities have various other cost recovery mechanisms for the recovery of costs, including those related to infrastructure replacement programs. (e) Deferred income tax charges are recovered and deferred income tax credits are amortized over the related property lives, which may range up to 53 years for Alabama Power, 57 years for Georgia Power, 55 years for Mississippi Power, and 80 years for Southern Company Gas. See Note 10 for additional information. As a result of the Tax Reform Legislation, these accounts include certain deferred income tax assets and liabilities not subject to normalization, as described further below: Alabama Power : Related amounts at December 31, 2022 include excess federal deferred income tax liabilities that are being returned to customers through bill credits of up to approximately $318 million in 2023, as discussed under "Alabama Power – Excess Accumulated Deferred Income Tax Accounting Order" herein. The Alabama PSC will determine the treatment of any remaining excess federal accumulated deferred income taxes at a future date. Remaining amounts are being recovered and amortized ratably over the related property lives. Georgia Power : Related amounts at December 31, 2022 include $145 million of deferred income tax assets related to CWIP for Plant Vogtle Units 3 and 4, the recovery of which is expected to be determined in a future regulatory proceeding. Mississippi Power : Related amounts at December 31, 2022 include $33 million of retail deferred income tax liabilities generally being amortized over three years through 2025. Southern Company Gas : Related amounts at December 31, 2022 include $1 million of deferred income tax liabilities being amortized through 2024. See "Southern Company Gas – Rate Proceedings" herein for additional information. (f) Effective January 1, 2023, Georgia Power is recovering $5 million annually for environmental remediation under the 2022 ARP. Southern Company Gas' costs are recovered through environmental cost recovery mechanisms when the remediation work is performed. See Note 3 under "Environmental Remediation" for additional information. (g) Recovered over either the remaining life of the original issue or, if refinanced, over the remaining life of the new issue. At December 31, 2022, the remaining amortization periods do not exceed 25 years for Alabama Power, 30 years for Georgia Power, 19 years for Mississippi Power, and five years for Southern Company Gas. (h) Recorded as earned by employees and recovered as paid, generally within one year. Includes both vacation and banked holiday pay, if applicable. (i) Effective January 1, 2023, balance is being amortized through Rate RSE over a five-year period ending in 2027. (j) Represents certain deferred operations and maintenance costs associated with software and cloud computing projects. For Alabama Power, costs are amortized ratably over the life of the related software, which ranges up to 10 years. See "Alabama Power – Software Accounting Order" herein for additional information. For Georgia Power, costs incurred through 2022 will be amortized over five years starting in 2023 and the recovery period for all future costs will be determined in its next base rate case. For Southern Company Gas, costs began being amortized ratably in July 2022 over the life of the related software, which ranges up to 10 years. (k) Nuclear outage costs are deferred to a regulatory asset when incurred and amortized over a subsequent period of 18 months for Alabama Power and up to 24 months for Georgia Power. See Note 5 for additional information. (l) Recovered over the remaining lives of the original debt issuances at acquisition, which range up to 16 years at December 31, 2022. (m) Fuel-hedging assets and liabilities are recorded over the life of the underlying hedged purchase contracts. Upon final settlement, actual costs incurred are recovered through the applicable traditional electric operating company's fuel cost recovery mechanism. Purchase contracts generally do not exceed three and a half years for Alabama Power, three years for Georgia Power, and four years for Mississippi Power. (n) Mississippi Power's balance represents deferred storm costs associated with Hurricanes Ida and Zeta being recovered through PEP over an eight-year period through 2029. (o) Represents the difference between Mississippi Power's revenue requirement for Plant Daniel Units 3 and 4 under purchase accounting and operating lease accounting. At December 31, 2022, consists of the $18 million retail portion being amortized through 2039 over the remaining life of the related property and the $9 million wholesale portion being amortized through 2035. (p) Includes $26 million of regulatory assets and $6 million of regulatory liabilities at December 31, 2022. The retail portion includes $17 million of regulatory assets and $6 million of regulatory liabilities that are expected to be fully amortized by 2023 and 2025, respectively. The wholesale portion includes $10 million of regulatory assets that are expected to be fully amortized by 2035. (q) Comprised of numerous immaterial components with remaining amortization periods generally not exceeding 21 years for Alabama Power, 10 years for Georgia Power, 14 years for Mississippi Power, and 20 years for Southern Company Gas at December 31, 2022. (r) Utilized as related expenses are incurred. See "Alabama Power – Rate NDR" and " – Reliability Reserve Accounting Order," "Georgia Power – Storm Damage Recovery," and "Mississippi Power – System Restoration Rider" and " – Reliability Reserve Accounting Order" herein and Note 1 under "Storm Damage and Reliability Reserves" for additional information. (s) Primarily includes approximately $62 million and $181 million at December 31, 2022 and 2021, respectively, for Alabama Power and $119 million and $5 million at December 31, 2022 and 2021, respectively, for Georgia Power as a result of each company exceeding its allowed retail return range. Georgia Power's balances also include immaterial amounts related to refunds for transmission service customers. See "Alabama Power – Rate RSE" and "Georgia Power – Rate Plans" herein for additional information. (t) Comprised of numerous immaterial components with remaining amortization periods generally not exceeding 11 years for Alabama Power, 10 years for Georgia Power, four years for Mississippi Power, and 20 years for Southern Company Gas at December 31, 2022. (u) Generally not earning a return as they are excluded from rate base or are offset in rate base by a corresponding asset or liability.
Public utilities general disclosures	Georgia Power will recover estimated adjustments through its existing tariffs as follows: Tariff 2023 2024 2025 (in millions) Traditional base $ 194 $ 275 $ 315 ECCR (21) 66 81 DSM 37 27 (2) MFF 6 9 9 Total $ 216 $ 377 $ 403 The Georgia PSC approved the following tariff adjustments under the 2019 ARP effective January 1, 2021 and 2022, respectively: Tariff 2021 2022 (in millions) Traditional base $ 120 $ 192 ECCR 2 (12) DSM (15) (25) MFF 4 2 Total $ 111 $ 157 The following table provides regulatory information for Southern Company Gas' natural gas distribution utilities: Nicor Gas Atlanta Gas Light Virginia Natural Gas Chattanooga Gas Authorized ROE at December 31, 2022 9.75% 10.25% 9.50% 9.80% Weather normalization mechanisms (a) ü ü Decoupled, including straight-fixed-variable rates (b) ü ü ü Regulatory infrastructure program rates (c) ü ü ü ü Bad debt rider (d) ü ü ü Energy efficiency plan (e) ü ü Annual base rate adjustment mechanism (f) ü ü Year of last base rate case decision 2021 2019 2021 2018 (a) Designed to help stabilize operating results by allowing recovery of costs in the event of unseasonal weather, but are not direct offsets to the potential impacts on earnings of weather and customer consumption. (b) Allows for recovery of fixed customer service costs separately from assumed natural gas volumes used by customers and provides a benchmark level of revenue for recovery. (c) Programs that update or expand distribution systems and LNG facilities. Atlanta Gas Light's infrastructure program, System Reinforcement Rider, is effective for 2022 through 2024. See "Rate Proceedings – Atlanta Gas Light" herein for additional information. Chattanooga Gas' pipeline replacement program costs are recovered through its annual base rate review mechanism. (d) The recovery (refund) of bad debt expense over (under) an established benchmark expense. The gas portion of bad debt expense is recovered through purchased gas adjustment mechanisms. Nicor Gas also has a rider to recover the non-gas portion of bad debt expense. (e) Recovery of costs associated with plans to achieve specified energy savings goals. (f) Regulatory mechanism allowing annual adjustments to base rates up or down based on authorized ROE and/or ROE range. The following table and discussions provide updates on the infrastructure replacement programs and capital projects at the natural gas distribution utilities at December 31, 2022. These programs are risk-based and designed to update and replace cast iron, bare steel, and mid-vintage plastic materials or expand Southern Company Gas' distribution systems to improve reliability and meet operational flexibility and growth. Utility Program Recovery Expenditures in 2022 Expenditures Since Project Inception Pipe Scope of Program Duration Last (in millions) (miles) (miles) (years) Nicor Gas Investing in Illinois (*) Rider $ 437 $ 2,945 1,297 1,854 9 2023 Virginia Natural Gas Steps to Advance Virginia's Energy (SAVE) Rider 69 411 525 695 13 2024 Atlanta Gas Light System Reinforcement Rider Rider 76 76 10 N/A 3 2024 Chattanooga Gas Pipeline Replacement Program Rate Base 5 7 5 73 7 2027 Total $ 587 $ 3,439 1,837 2,622 (*) Includes replacement of pipes, compressors, and transmission mains along with other improvements such as new meters. Scope of program miles is an estimate and subject to change. Recovery of program costs is described under "Nicor Gas" herein.
Schedule of revised cost and schedule	Georgia Power's approximate proportionate share of the remaining estimated capital cost to complete Plant Vogtle Units 3 and 4, including contingency, through the end of the second quarter 2023 and the first quarter 2024, respectively, is as follows: (in millions) Base project capital cost forecast (a)(b) $ 10,533 Construction contingency estimate 60 Total project capital cost forecast (a)(b) 10,593 Net investment at December 31, 2022 (b) (9,521) Remaining estimate to complete $ 1,072 (a) Includes approximately $610 million of costs that are not shared with the other Vogtle Owners, including $33 million of construction monitoring costs approved for recovery by the Georgia PSC in its nineteenth VCM order, and approximately $407 million of incremental costs under the cost-sharing and tender provisions of the joint ownership agreements described below. Excludes financing costs expected to be capitalized through AFUDC of approximately $421 million, of which $304 million had been accrued through December 31, 2022. (b) Net of $1.7 billion received from Toshiba under the Guarantee Settlement Agreement and approximately $188 million in related customer refunds.

CONTINGENCIES, COMMITMENTS, A_2

CONTINGENCIES, COMMITMENTS, AND GUARANTEES (Tables)	12 Months Ended
	Dec. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Schedule of regulatory assets and liabilities	At December 31, 2022 and 2021, the environmental remediation liability and the balance of under recovered environmental remediation costs were reflected in the balance sheets of Southern Company, Georgia Power, and Southern Company Gas as shown in the table below. Alabama Power did not have environmental remediation liabilities at December 31, 2022 or 2021. Mississippi Power did not have environmental remediation liabilities at December 31, 2022 and had an immaterial balance at December 31, 2021. Southern Company Georgia Southern Company Gas (in millions) December 31, 2022: Environmental remediation liability: Other current liabilities $ 65 $ 15 $ 49 Accrued environmental remediation 207 — 207 Under recovered environmental remediation costs: Other regulatory assets, current $ 59 $ 5 $ 54 Other regulatory assets, deferred 235 20 215 December 31, 2021: Environmental remediation liability: Other current liabilities $ 69 $ 17 $ 52 Accrued environmental remediation 197 — 197 Under recovered environmental remediation costs: Other regulatory assets, current $ 71 $ 12 $ 59 Other regulatory assets, deferred 231 23 208
Expected future contractual obligations	Southern Company Gas' expected future contractual obligations for pipeline charges, storage capacity, and gas supply that are not recognized on the balance sheets at December 31, 2022 were as follows: Pipeline Charges, Storage Capacity, and Gas Supply (in millions) 2023 $ 637 2024 455 2025 390 2026 212 2027 134 Thereafter 871 Total $ 2,699

REVENUE FROM CONTRACTS WITH C_2

REVENUE FROM CONTRACTS WITH CUSTOMERS (Tables)	12 Months Ended
	Dec. 31, 2022
Revenue from Contract with Customer [Abstract]
Disaggregation of revenue	The following table disaggregates revenue from contracts with customers for the periods presented: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) 2022 Operating revenues Retail electric revenues Residential $ 6,604 $ 2,638 $ 3,664 $ 302 $ — $ — Commercial 5,369 1,685 3,385 299 — — Industrial 3,764 1,507 1,921 336 — — Other 102 14 79 9 — — Total retail electric revenues 15,839 5,844 9,049 946 — — Natural gas distribution revenues Residential 2,843 — — — — 2,843 Commercial 763 — — — — 763 Transportation 1,186 — — — — 1,186 Industrial 84 — — — — 84 Other 342 — — — — 342 Total natural gas distribution revenues 5,218 — — — — 5,218 Wholesale electric revenues PPA energy revenues 2,274 489 130 16 1,673 — PPA capacity revenues 596 194 47 4 356 — Non-PPA revenues 250 200 30 690 740 — Total wholesale electric revenues 3,120 883 207 710 2,769 — Other natural gas revenues Gas marketing services 636 — — — — 636 Other natural gas revenues 51 — — — — 51 Total natural gas revenues 687 — — — — 687 Other revenues 1,077 194 446 47 36 — Total revenue from contracts with customers 25,941 6,921 9,702 1,703 2,805 5,905 Other revenue sources (a) 3,338 896 1,882 (9) 564 57 Total operating revenues $ 29,279 $ 7,817 $ 11,584 $ 1,694 $ 3,369 $ 5,962 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) 2021 Operating revenues Retail electric revenues Residential $ 6,207 $ 2,467 $ 3,471 $ 269 $ — $ — Commercial 4,877 1,600 3,010 267 — — Industrial 3,067 1,386 1,391 290 — — Other 93 17 68 8 — — Total retail electric revenues 14,244 5,470 7,940 834 — — Natural gas distribution revenues Residential 1,799 — — — — 1,799 Commercial 470 — — — — 470 Transportation 1,038 — — — — 1,038 Industrial 49 — — — — 49 Other 269 — — — — 269 Total natural gas distribution revenues 3,625 — — — — 3,625 Wholesale electric revenues PPA energy revenues 1,122 184 95 11 854 — PPA capacity revenues 493 115 55 5 323 — Non-PPA revenues 236 170 21 401 398 — Total wholesale electric revenues 1,851 469 171 417 1,575 — Other natural gas revenues Wholesale gas services 2,168 — — — — 2,168 Gas marketing services 464 — — — — 464 Other natural gas revenues 36 — — — — 36 Total other natural gas revenues 2,668 — — — — 2,668 Other revenues 1,075 202 452 31 30 — Total revenue from contracts with customers 23,463 6,141 8,563 1,282 1,605 6,293 Other revenue sources (a) 3,349 272 697 40 611 1,786 Other adjustments (b) (3,699) — — — — (3,699) Total operating revenues $ 23,113 $ 6,413 $ 9,260 $ 1,322 $ 2,216 $ 4,380 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) 2020 Operating revenues Retail electric revenues Residential $ 6,113 $ 2,377 $ 3,476 $ 260 $ — $ — Commercial 4,699 1,512 2,933 254 — — Industrial 2,775 1,293 1,197 285 — — Other 90 21 60 9 — — Total retail electric revenues 13,677 5,203 7,666 808 — — Natural gas distribution revenues Residential 1,338 — — — — 1,338 Commercial 340 — — — — 340 Transportation 971 — — — — 971 Industrial 30 — — — — 30 Other 209 — — — — 209 Total natural gas distribution revenues 2,888 — — — — 2,888 Wholesale electric revenues PPA energy revenues 735 133 42 9 570 — PPA capacity revenues 454 108 50 3 296 — Non-PPA revenues 210 43 10 311 239 — Total wholesale electric revenues 1,399 284 102 323 1,105 — Other natural gas revenues Wholesale gas services 1,727 — — — — 1,727 Gas marketing services 391 — — — — 391 Other natural gas revenues 33 — — — — 33 Total other natural gas revenues 2,151 — — — — 2,151 Other revenues 982 159 447 26 14 — Total revenue from contracts with customers 21,097 5,646 8,215 1,157 1,119 5,039 Other revenue sources (a) 3,764 184 94 15 614 2,881 Other adjustments (b) (4,486) — — — — (4,486) Total operating revenues $ 20,375 $ 5,830 $ 8,309 $ 1,172 $ 1,733 $ 3,434 (a) Other revenue sources relate to revenues from customers accounted for as derivatives and leases, alternative revenue programs at Southern Company Gas, and cost recovery mechanisms and revenues that meet other scope exceptions for revenues from contracts with customers at the traditional electric operating companies. (b) Other adjustments relate to the cost of Southern Company Gas' energy and risk management activities. Wholesale gas services revenues are presented net of the related costs of those activities on the statement of income. See Notes 15 and 16 under "Southern Company Gas" for information on the sale of Sequent and components of wholesale gas services' operating revenues, respectively.
Contract with customer, asset and liability	The following table reflects the closing balances of receivables, contract assets, and contract liabilities related to revenues from contracts with customers at December 31, 2022 and 2021: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Accounts Receivable At December 31, 2022 $ 3,123 $ 696 $ 922 $ 92 $ 237 $ 1,107 At December 31, 2021 2,504 589 736 73 149 753 Contract Assets At December 31, 2022 $ 156 $ 2 $ 89 $ — $ — $ — At December 31, 2021 117 2 63 — 1 — Contract Liabilities At December 31, 2022 $ 45 $ 4 $ 9 $ — $ 1 $ — At December 31, 2021 57 4 14 — 1 —
Revenue, remaining performance obligation, expected timing of satisfaction	Revenues from contracts with customers related to these performance obligations remaining at December 31, 2022 are expected to be recognized as follows: 2023 2024 2025 2026 2027 Thereafter (in millions) Southern Company $ 640 $ 483 $ 332 $ 311 $ 315 $ 2,076 Alabama Power 24 7 6 — — — Georgia Power 74 39 22 11 10 10 Southern Power 355 345 302 303 310 2,077 Southern Company Gas 34 29 — — — —

PROPERTY, PLANT, AND EQUIPMENT

PROPERTY, PLANT, AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2022
Property, Plant and Equipment [Abstract]
Property, plant and equipment	The Registrants' property, plant, and equipment in service consisted of the following at December 31, 2022 and 2021: At December 31, 2022: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Electric utilities: Generation $ 51,756 $ 15,920 $ 17,755 $ 2,826 $ 14,619 $ — Transmission 14,201 5,658 7,576 927 — — Distribution 24,200 9,154 13,819 1,228 — — General/other 5,806 2,740 2,729 273 39 — Electric utilities' plant in service 95,963 33,472 41,879 5,254 14,658 — Southern Company Gas: Natural gas distribution utilities transportation and distribution 16,810 — — — — 16,810 Storage facilities 1,553 — — — — 1,553 Other 1,360 — — — — 1,360 Southern Company Gas plant in service 19,723 — — — — 19,723 Other plant in service 1,843 — — — — — Total plant in service $ 117,529 $ 33,472 $ 41,879 $ 5,254 $ 14,658 $ 19,723 At December 31, 2021: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Electric utilities: Generation $ 53,803 $ 16,631 $ 19,184 $ 2,791 $ 14,551 $ — Transmission 13,406 5,334 7,132 900 — — Distribution 22,236 8,643 12,437 1,156 — — General/other 5,423 2,527 2,579 259 34 — Electric utilities' plant in service 94,868 33,135 41,332 5,106 14,585 — Southern Company Gas: Natural gas distribution utilities transportation and distribution 15,714 — — — — 15,714 Storage facilities 1,315 — — — — 1,315 Other 1,851 — — — — 1,851 Southern Company Gas plant in service 18,880 — — — — 18,880 Other plant in service 1,844 — — — — — Total plant in service $ 115,592 $ 33,135 $ 41,332 $ 5,106 $ 14,585 $ 18,880 Southern Power Generating Facility Useful life Natural gas Up to 50 years Solar Up to 35 years Wind Up to 35 years (*) (*) Effective January 1, 2022, Southern Power revised the depreciable lives of its wind generating facilities from up to 30 years to up to 35 years. This revision resulted in an immaterial decrease in depreciation for 2022.
Deferred cloud implementation costs	At December 31, 2022 and 2021, deferred cloud implementation costs, net of amortization, which are generally included in other deferred charges and assets on the Registrants' balance sheets, are as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Deferred cloud implementation costs, net: At December 31, 2022 $ 345 $ 81 $ 108 $ 14 $ 18 $ 54 At December 31, 2021 240 54 81 11 14 35
Composite straight-line rates	Costs for these services from SCS in 2022, 2021, and 2020 were as follows: Alabama Georgia Mississippi Southern Southern Company Gas (in millions) 2022 $ 549 $ 762 $ 115 $ 86 $ 262 2021 504 663 120 89 239 2020 478 639 149 87 237 Mississippi Southern (in millions) 2022 $ 4 $ 29 2021 9 15 2020 4 8 Alabama Georgia Southern Southern Company Gas (in millions) 2022 $ 18 $ 99 $ 37 $ 27 2021 14 108 31 29 2020 15 108 29 29 2022 2021 2020 Alabama Power 2.7 % 2.7 % 2.6 % Georgia Power 3.3 % 3.3 % 3.0 % Mississippi Power 3.4 % 3.6 % 3.7 % Southern Company Gas 2.7 % 2.8 % 2.8 %
Ownership and investment in jointly-owned facilities	At December 31, 2022, the Registrants' percentage ownership and investment (exclusive of nuclear fuel) in jointly-owned facilities in commercial operation were as follows: Facility (Type) Percent Plant in Service Accumulated CWIP (in millions) Alabama Power Greene County (natural gas) Units 1 and 2 60.0 % (a) $ 193 $ 85 $ — Plant Miller (coal) Units 1 and 2 91.8 (b) 2,148 712 13 Georgia Power Plant Hatch (nuclear) 50.1 % (c) $ 1,401 $ 671 $ 62 Plant Vogtle (nuclear) Units 1 and 2 45.7 (c) 3,628 2,298 94 Plant Scherer (coal) Units 1 and 2 8.4 (c) 276 106 1 Plant Scherer (coal) Unit 3 75.0 (c) 1,317 567 6 Rocky Mountain (pumped storage) 25.4 (d) 184 153 1 Mississippi Power Greene County (natural gas) Units 1 and 2 40.0 % (a) $ 125 $ 70 $ — Plant Daniel (coal) Units 1 and 2 50.0 (e) 765 257 30 Southern Company Gas Dalton Pipeline (natural gas pipeline) 50.0 % (f) $ 271 $ 23 $ — (a) Jointly owned by Alabama Power and Mississippi Power and operated and maintained by Alabama Power. (b) Jointly owned with PowerSouth and operated and maintained by Alabama Power. (c) Georgia Power owns undivided interests in Plants Hatch, Vogtle Units 1 and 2, and Scherer in varying amounts jointly with one or more of the following entities: OPC, MEAG Power, Dalton, FP&L, and JEA. Georgia Power has been contracted to operate and maintain the plants as agent for the co-owners and is jointly and severally liable for third party claims related to these plants. (d) Jointly owned with OPC, which is the operator of the plant. (e) Jointly owned by FP&L and Mississippi Power. In accordance with the operating agreement, Mississippi Power acts as FP&L's agent with respect to the operation and maintenance of these units. See Note 3 under "Other Matters – Mississippi Power – Plant Daniel" for additional information. (f) Jointly owned with The Williams Companies, Inc., the Dalton Pipeline is a 115-mile natural gas pipeline that serves as an extension of the Transcontinental Gas Pipe Line Company, LLC pipeline system into northwest Georgia. Southern Company Gas leases its 50% undivided ownership for approximately $26 million annually through 2042. The lessee is responsible for maintaining the pipeline during the lease term and for providing service to transportation customers under its FERC-regulated tariff.

ASSET RETIREMENT OBLIGATIONS (T

ASSET RETIREMENT OBLIGATIONS (Tables)	12 Months Ended
	Dec. 31, 2022
Asset Retirement Obligation Disclosure [Abstract]
Details of AROs included in the balance sheets	Details of the AROs included in the balance sheets are as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power (*) (in millions) Balance at December 31, 2020 $ 10,684 $ 3,974 $ 6,265 $ 176 $ 95 Liabilities incurred 26 — 3 — 23 Liabilities settled (456) (202) (210) (24) — Accretion 407 156 236 7 5 Cash flow revisions 1,026 406 530 31 8 Balance at December 31, 2021 $ 11,687 $ 4,334 $ 6,824 $ 190 $ 131 Liabilities incurred 36 — 35 — — Liabilities settled (455) (205) (212) (20) — Accretion 406 158 231 6 6 Cash flow revisions (834) — (844) 3 7 Balance at December 31, 2022 $ 10,840 $ 4,287 $ 6,034 $ 179 $ 144 (*) Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets.
Investment securities in the Funds	Investment securities in the Funds for December 31, 2022 and 2021 were as follows: Southern Company Alabama Georgia (in millions) At December 31, 2022: Equity securities $ 1,095 $ 690 $ 405 Debt securities 838 267 571 Other securities 210 168 42 Total investment securities in the Funds $ 2,143 $ 1,125 $ 1,018 At December 31, 2021: Equity securities $ 1,358 $ 849 $ 509 Debt securities 986 316 670 Other securities 197 159 38 Total investment securities in the Funds $ 2,541 $ 1,324 $ 1,217
Fair value increases (decreases) of the Funds	The fair value increases (decreases) of the Funds, including unrealized gains (losses) and reinvested interest and dividends and excluding the Funds' expenses, for 2022, 2021, and 2020 are shown in the table below. Southern Company Alabama Georgia (in millions) Fair value increases (decreases) 2022 $ (360) $ (171) $ (189) 2021 274 200 74 2020 280 142 138 Unrealized gains (losses) At December 31, 2022 $ (391) $ (204) $ (187) At December 31, 2021 (27) (30) 3 At December 31, 2020 220 121 99 At December 31, 2022, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 18 $ 181 $ — $ — $ 199 Interest rate derivatives — 12 — — 12 Investments in trusts: (b)(c) Domestic equity 651 178 — — 829 Foreign equity 125 150 — — 275 U.S. Treasury and government agency securities — 285 — — 285 Municipal bonds — 51 — — 51 Pooled funds – fixed income — 7 — — 7 Corporate bonds — 412 — — 412 Mortgage and asset backed securities — 90 — — 90 Private equity — — — 161 161 Cash and cash equivalents 4 — — — 4 Other 37 12 — — 49 Cash equivalents 1,427 20 — — 1,447 Other investments 9 26 — — 35 Total $ 2,271 $ 1,424 $ — $ 161 $ 3,856 Liabilities: Energy-related derivatives (a) $ 32 $ 178 $ — $ — $ 210 Interest rate derivatives — 302 — — 302 Foreign currency derivatives — 216 — — 216 Contingent consideration — — 12 — 12 Other — 13 — — 13 Total $ 32 $ 709 $ 12 $ — $ 753 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 62 $ — $ — $ 62 Nuclear decommissioning trusts: (b) Domestic equity 396 169 — — 565 Foreign equity 125 — — — 125 U.S. Treasury and government agency securities — 19 — — 19 Municipal bonds — 1 — — 1 Corporate bonds — 225 — — 225 Mortgage and asset backed securities — 22 — — 22 Private equity — — — 161 161 Other 7 — — — 7 Cash equivalents 438 20 — — 458 Other investments — 26 — — 26 Total $ 966 $ 544 $ — $ 161 $ 1,671 Liabilities: Energy-related derivatives $ — $ 39 $ — $ — $ 39 Georgia Power Assets: Energy-related derivatives $ — $ 42 $ — $ — $ 42 Nuclear decommissioning trusts: (b)(c) Domestic equity 255 1 — — 256 Foreign equity — 149 — — 149 U.S. Treasury and government agency securities — 266 — — 266 Municipal bonds — 50 — — 50 Corporate bonds — 187 — — 187 Mortgage and asset backed securities — 68 — — 68 Other 30 12 — — 42 Cash equivalents 355 — — — 355 Total $ 640 $ 775 $ — $ — $ 1,415 Liabilities: Energy-related derivatives $ — $ 62 $ — $ — $ 62 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 59 $ — $ — $ 59 Cash equivalents 47 — — — 47 Total $ 47 $ 59 $ — $ — $ 106 Liabilities: Energy-related derivatives $ — $ 32 $ — $ — $ 32 Southern Power Assets: Energy-related derivatives $ — $ 8 $ — $ — $ 8 Liabilities: Energy-related derivatives $ — $ 12 $ — $ — $ 12 Foreign currency derivatives — 47 — — 47 Contingent consideration — — 12 — 12 Other — 13 — — 13 Total $ — $ 72 $ 12 $ — $ 84 Southern Company Gas Assets: Energy-related derivatives (a) $ 18 $ 10 $ — $ — $ 28 Non-qualified deferred compensation trusts: Domestic equity — 8 — — 8 Foreign equity — 1 — — 1 Pooled funds - fixed income — 7 — — 7 Cash and cash equivalents 4 — — — 4 Cash equivalents 50 — — — 50 Total $ 72 $ 26 $ — $ — $ 98 Liabilities: Energy-related derivatives (a)(b) $ 32 $ 33 $ — $ — $ 65 Interest rate derivatives — 86 — — 86 Total $ 32 $ 119 $ — $ — $ 151 (a) Excludes cash collateral of $41 million. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information. (c) Includes investment securities pledged to creditors and collateral received and excludes payables related to the securities lending program. See Note 6 under "Nuclear Decommissioning" for additional information. At December 31, 2021, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2021: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 24 $ 195 $ — $ — $ 219 Interest rate derivatives — 19 — — 19 Investments in trusts: (b)(c) Domestic equity 791 225 — — 1,016 Foreign equity 165 188 — — 353 U.S. Treasury and government agency securities — 314 — — 314 Municipal bonds — 56 — — 56 Pooled funds – fixed income — 13 — — 13 Corporate bonds 1 522 — — 523 Mortgage and asset backed securities — 93 — — 93 Private equity — — — 150 150 Cash and cash equivalents 2 — — — 2 Other 22 25 — — 47 Cash equivalents 1,160 14 — — 1,174 Other investments 9 35 — — 44 Total $ 2,174 $ 1,699 $ — $ 150 $ 4,023 Liabilities: Energy-related derivatives (a) $ 10 $ 36 $ — $ — $ 46 Interest rate derivatives — 29 — — 29 Foreign currency derivatives — 79 — — 79 Contingent consideration — — 14 — 14 Other — 13 — — 13 Total $ 10 $ 157 $ 14 $ — $ 181 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2021: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 55 $ — $ — $ 55 Nuclear decommissioning trusts: (b) Domestic equity 468 216 — — 684 Foreign equity 165 — — — 165 U.S. Treasury and government agency securities — 21 — — 21 Municipal bonds — 1 — — 1 Corporate bonds 1 271 — — 272 Mortgage and asset backed securities — 22 — — 22 Private equity — — — 150 150 Other 9 — — — 9 Cash equivalents 839 14 — — 853 Other investments — 35 — — 35 Total $ 1,482 $ 635 $ — $ 150 $ 2,267 Liabilities: Energy-related derivatives $ — $ 11 $ — $ — $ 11 Georgia Power Assets: Energy-related derivatives $ — $ 75 $ — $ — $ 75 Nuclear decommissioning trusts: (b)(c) Domestic equity 323 1 — — 324 Foreign equity — 185 — — 185 U.S. Treasury and government agency securities — 293 — — 293 Municipal bonds — 55 — — 55 Corporate bonds — 251 — — 251 Mortgage and asset backed securities — 71 — — 71 Other 13 25 — — 38 Total $ 336 $ 956 $ — $ — $ 1,292 Liabilities: Energy-related derivatives $ — $ 8 $ — $ — $ 8 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2021: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 56 $ — $ — $ 56 Cash equivalents 40 — — — 40 Total $ 40 $ 56 $ — $ — $ 96 Liabilities: Energy-related derivatives $ — $ 5 $ — $ — $ 5 Southern Power Assets: Energy-related derivatives $ — $ 4 $ — $ — $ 4 Liabilities: Foreign currency derivatives $ — $ 16 $ — $ — $ 16 Contingent consideration — — 14 — 14 Other — 13 — — 13 Total $ — $ 29 $ 14 $ — $ 43 Southern Company Gas Assets: Energy-related derivatives (a) $ 24 $ 5 $ — $ — $ 29 Interest rate derivatives — 6 — — 6 Non-qualified deferred compensation trusts: Domestic equity — 8 — — 8 Foreign equity — 3 — — 3 Pooled funds - fixed income — 13 — — 13 Cash equivalents 2 — — — 2 Total $ 26 $ 35 $ — $ — $ 61 Liabilities: Energy-related derivatives (a)(b) $ 10 $ 12 $ — $ — $ 22 Interest rate derivatives — 5 — — 5 Total $ 10 $ 17 $ — $ — $ 27 (a) Excludes immaterial cash collateral. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information. (c) Includes investment securities pledged to creditors and collateral received and excludes payables related to the securities lending program. See Note 6 under "Nuclear Decommissioning" for additional information.
Accumulated provisions for the external decommissioning trust funds	At December 31, 2022 and 2021, the accumulated provisions for the external decommissioning trust funds were as follows: 2022 2021 (in millions) Alabama Power Plant Farley $ 1,125 $ 1,324 Georgia Power Plant Hatch $ 628 $ 757 Plant Vogtle Units 1 and 2 382 460 Plant Vogtle Unit 3 8 — Total $ 1,018 $ 1,217
Estimated costs of decommissioning	The estimated costs of decommissioning at December 31, 2022 based on the most current studies, which were performed in 2018 for Alabama Power and in 2021 for Georgia Power, were as follows: Plant Plant Hatch (*) Plant Vogtle Units 1 and 2 (*) Decommissioning periods: Beginning year 2037 2034 2047 Completion year 2076 2075 2079 (in millions) Site study costs: Radiated structures $ 1,234 $ 771 $ 628 Spent fuel management 387 186 170 Non-radiated structures 99 61 85 Total site study costs $ 1,720 $ 1,018 $ 883 (*) Based on Georgia Power's ownership interests.

CONSOLIDATED ENTITIES AND EQU_2

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS (Tables)	12 Months Ended
	Dec. 31, 2022
Equity Method Investments and Joint Ventures [Abstract]
Equity method investments	The carrying amounts of Southern Company Gas' equity method investments at December 31, 2022 and 2021 and related earnings (loss) from those investments for the years ended December 31, 2022, 2021, and 2020 were as follows: Investment Balance December 31, 2022 December 31, 2021 (in millions) SNG $ 1,243 $ 1,129 Other (*) 33 44 Total $ 1,276 $ 1,173 (*) Balance at December 31, 2022 reflects an $11 million distribution received in 2022 from PennEast Pipeline.
Equity method investments related income	Earnings (Loss) from Equity Method Investments 2022 2021 2020 (in millions) SNG $ 146 $ 127 $ 129 PennEast Pipeline (*) — (81) 7 Other 2 4 5 Total $ 148 $ 50 $ 141 (*) For 2021, includes pre-tax impairment charges totaling $84 million. See "PennEast Pipeline Project" herein for additional information, including the September 2021 cancellation of the project. For 2020, earnings primarily result from AFUDC equity recorded by the project entity.

FINANCING (Tables)

FINANCING (Tables)	12 Months Ended
	Dec. 31, 2022
Debt Disclosure [Abstract]
Summary of long-term debt	Details of long-term debt at December 31, 2022 and 2021 are provided in the following table: At December 31, 2022 Balance Outstanding at Maturity Weighted Average 2022 2021 (in millions) Southern Company Senior notes (a) 2023-2052 3.87% $ 35,683 $ 33,120 Junior subordinated notes 2024-2081 4.58% 8,836 8,918 FFB loans (b) 2023-2044 2.88% 4,874 4,962 Revenue bonds (c) 2024-2062 3.25% 2,844 2,662 First mortgage bonds (d) 2023-2062 3.46% 2,275 2,100 Medium-term notes 2026-2027 7.03% 84 130 Other long-term debt 2024-2045 4.96% 167 270 Finance lease obligations (e) 314 215 Unamortized fair value adjustment 330 359 Unamortized debt premium (discount), net (193) (216) Unamortized debt issuance expenses (273) (243) Total long-term debt 54,941 52,277 Less: Amount due within one year 4,285 2,157 Total long-term debt excluding amount due within one year $ 50,656 $ 50,120 Alabama Power Senior notes 2023-2052 3.86% $ 9,675 $ 8,725 Revenue bonds (c) 2024-2038 3.44% 995 995 Other long-term debt 2026 5.62% 45 45 Finance lease obligations (e) 5 4 Unamortized debt premium (discount), net (18) (18) Unamortized debt issuance expenses (72) (64) Total long-term debt 10,630 9,687 Less: Amount due within one year 301 751 Total long-term debt excluding amount due within one year $ 10,329 $ 8,936 Georgia Power Senior notes 2023-2052 3.90% $ 7,925 $ 6,825 Junior subordinated notes 2077 5.00% 270 270 FFB loans (b) 2023-2044 2.88% 4,874 4,962 Revenue bonds (c) 2025-2062 3.13% 1,738 1,591 Other long-term debt — 125 Finance lease obligations (e) 238 136 Unamortized debt premium (discount), net (18) (11) Unamortized debt issuance expenses (117) (114) Total long-term debt 14,910 13,784 Less: Amount due within one year 901 675 Total long-term debt excluding amount due within one year $ 14,009 $ 13,109 At December 31, 2022 Balance Outstanding at Maturity Weighted Average 2022 2021 (in millions) Mississippi Power Senior notes 2024-2051 3.93% $ 1,425 $ 1,425 Revenue bonds (c) 2025-2052 3.55% 111 76 Finance lease obligations (e) 17 18 Unamortized debt premium (discount), net 2 2 Unamortized debt issuance expenses (10) (10) Total long-term debt 1,545 1,511 Less: Amount due within one year 1 1 Total long-term debt excluding amount due within one year $ 1,544 $ 1,510 Southern Power Senior notes (a) 2023-2046 3.92% $ 2,998 $ 3,711 Unamortized debt premium (discount), net (5) (6) Unamortized debt issuance expenses (14) (17) Total long-term debt 2,979 3,688 Less: Amount due within one year 290 679 Total long-term debt excluding amount due within one year $ 2,689 $ 3,009 Southern Company Gas Senior notes 2023-2051 4.08% $ 4,769 $ 4,348 First mortgage bonds (d) 2023-2062 3.46% 2,275 2,100 Medium-term notes 2026-2027 7.03% 84 130 Other long-term debt 2024-2045 3.81% 22 — Unamortized fair value adjustment 330 359 Unamortized debt premium (discount), net (8) (35) Unamortized debt issuance expenses (30) — Total long-term debt 7,442 6,902 Less: Amount due within one year 400 47 Total long-term debt excluding amount due within one year $ 7,042 $ 6,855 (a) Includes a fair value gain (loss) of $(31) million and $5 million at December 31, 2022 and 2021, respectively, related to Southern Power's foreign currency hedge on its euro-denominated senior notes. (b) Secured by a first priority lien on (i) Georgia Power's undivided ownership interest in Plant Vogtle Units 3 and 4 (primarily the units under construction, the related real property, and any nuclear fuel loaded in the reactor core) and (ii) Georgia Power's rights and obligations under the principal contracts relating to Plant Vogtle Units 3 and 4. See "DOE Loan Guarantee Borrowings" herein for additional information. (c) Revenue bond obligations represent loans to the traditional electric operating companies from public authorities of funds derived from sales by such authorities of revenue bonds issued to finance pollution control and solid waste disposal and wastewater facilities. In some cases, the revenue bond obligations represent obligations under installment sales agreements with respect to facilities constructed with the proceeds of revenue bonds issued by public authorities. The traditional electric operating companies are required to make payments sufficient for the authorities to meet principal and interest requirements of such bonds. Proceeds from certain issuances are restricted until qualifying expenditures are incurred. (d) Secured by substantially all of Nicor Gas' properties. (e) Secured by the underlying lease ROU asset. See Note 9 for additional information.
Schedule of maturities of long-term debt for the next five years	Maturities of long-term debt for the next five years are as follows: Southern Company (a) Alabama Power Georgia Power (b) Mississippi Power Southern Power (c) Southern Company (in millions) 2023 $ 4,293 $ 301 $ 901 $ 1 $ 290 $ 400 2024 2,280 23 499 201 — — 2025 1,699 251 145 12 500 300 2026 3,726 46 445 1 964 530 2027 2,074 550 510 11 — 154 (a) See notes (b) and (c) below. (b) Amounts include principal amortization related to the FFB borrowings; however, the final maturity date is February 20, 2044. See "DOE Loan Guarantee Borrowings" herein for additional information. (c) Southern Power's 2026 maturities include $564 million of euro-denominated debt at the U.S. dollar denominated hedge settlement amount.
Summary of committed credit arrangements	At December 31, 2022, committed credit arrangements with banks were as follows: Expires Company 2023 2024 2025 2026 Total Unused Due within (in millions) Southern Company parent $ — $ — $ — $ 2,000 $ 2,000 $ 1,998 $ — Alabama Power — 550 — 700 1,250 1,250 — Georgia Power — — — 1,750 1,750 1,726 — Mississippi Power — 150 125 — 275 275 — Southern Power (a) — — — 600 600 569 — Southern Company Gas (b) 250 — — 1,500 1,750 1,748 250 SEGCO 30 — — — 30 30 30 Southern Company $ 280 $ 700 $ 125 $ 6,550 $ 7,655 $ 7,596 $ 280 (a) Does not include Southern Power Company's two $75 million continuing letter of credit facilities for standby letters of credit, of which $9 million and $5 million, respectively, was unused at December 31, 2022. In December 2022, Southern Power amended one of the $75 million letter of credit facilities, which extended the expiration date from 2023 to 2025. The second $75 million letter of credit facility also expires in 2025. Southern Power's subsidiaries are not parties to its bank credit arrangements or letter of credit facilities. (b) Southern Company Gas, as the parent entity, guarantees the obligations of Southern Company Gas Capital, which is the borrower of $800 million of the credit arrangement expiring in 2026. Southern Company Gas' committed credit arrangement expiring in 2026 also includes $700 million for which Nicor Gas is the borrower and which is restricted for working capital needs of Nicor Gas. Pursuant to the multi-year credit arrangement expiring in 2026, the allocations between Southern Company Gas Capital and Nicor Gas may be adjusted. Nicor Gas is also the borrower under a $250 million credit arrangement expiring in 2023. See "Structural Considerations" herein for additional information.
Details of short-term borrowings	Details of short-term borrowings for the applicable Registrants were as follows: Notes Payable at December 31, 2022 Notes Payable at December 31, 2021 Amount Weighted Average Amount Weighted Average (in millions) (in millions) Southern Company Commercial paper $ 809 4.7 % $ 1,140 0.3 % Short-term bank debt 1,800 5.0 % 300 0.7 % Total $ 2,609 4.9 % $ 1,440 0.4 % Georgia Power Short-term bank debt $ 1,600 5.0 % $ — — % Southern Power Commercial paper $ 225 4.7 % $ 211 0.3 % Southern Company Gas Commercial paper: Southern Company Gas Capital $ 285 4.8 % $ 379 0.3 % Nicor Gas 283 4.6 % 530 0.3 % Short-term bank debt: Nicor Gas 200 4.9 % 300 0.7 % Total $ 768 4.7 % $ 1,209 0.4 %
Shares used to compute diluted EPS	Shares used to compute diluted EPS were as follows: Average Common Stock Shares 2022 2021 2020 (in millions) As reported shares 1,075 1,061 1,058 Effect of stock-based compensation 6 7 7 Diluted shares 1,081 1,068 1,065
Schedule of preferred stock	Preferred Stock Redeemed During 2022 Par Value/Stated Capital Per Share Shares Redemption 4.92% Preferred Stock $100 80,000 $103.23 4.72% Preferred Stock $100 50,000 $102.18 4.64% Preferred Stock $100 60,000 $103.14 4.60% Preferred Stock $100 100,000 $104.20 4.52% Preferred Stock $100 50,000 $102.93 4.20% Preferred Stock $100 135,115 $105.00 5.00% Class A Preferred Stock $25 10,000,000 $25.00

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2022
Leases [Abstract]
Major categories of lease obligations	The major categories of lease obligations are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2022 Electric generating units (*) $ 760 $ 59 $ 1,163 $ — $ — $ — Real estate/land 885 4 54 2 542 36 Communication towers 141 2 4 — — 23 Railcars 34 12 18 3 — — Other 79 4 1 21 — 1 Total $ 1,899 $ 81 $ 1,240 $ 26 $ 542 $ 60 At December 31, 2021 Electric generating units (*) $ 802 $ 104 $ 1,217 $ — $ — $ — Real estate/land 876 3 49 2 526 45 Communication towers 156 2 4 — — 24 Railcars 32 10 20 2 — — Other 103 5 1 24 — 1 Total $ 1,969 $ 124 $ 1,291 $ 28 $ 526 $ 70 (*) Amounts related to affiliate leases are eliminated in consolidation for Southern Company. See "Contracts that Contain a Lease" herein for additional information.
Balance sheet amounts recorded for operating and financing leases	Balance sheet amounts recorded for operating and finance leases are as follows: Southern Company Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) At December 31, 2022 Operating Leases Operating lease ROU assets, net $ 1,531 $ 71 $ 1,007 $ 9 $ 489 $ 57 Operating lease obligations - current $ 197 $ 9 $ 151 $ 4 $ 28 $ 9 Operating lease obligations - non-current 1,388 67 851 5 514 51 Total operating lease obligations (*) $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance Leases Finance lease ROU assets, net $ 292 $ 5 $ 205 $ 16 $ — $ — Finance lease obligations - current $ 18 $ 2 $ 16 $ 1 $ — $ — Finance lease obligations - non-current 296 3 222 16 — — Total finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ — At December 31, 2021 Operating Leases Operating lease ROU assets, net $ 1,701 $ 108 $ 1,157 $ 10 $ 479 $ 70 Operating lease obligations - current $ 250 $ 54 $ 156 $ 4 $ 28 $ 11 Operating lease obligations - non-current 1,503 66 999 6 497 59 Total operating lease obligations (*) $ 1,754 $ 121 $ 1,155 $ 10 $ 525 $ 70 Finance Leases Finance lease ROU assets, net $ 197 $ 4 $ 104 $ 17 $ — $ — Finance lease obligations - current $ 16 $ 1 $ 10 $ 1 $ — $ — Finance lease obligations - non-current 199 3 126 17 — — Total finance lease obligations $ 215 $ 4 $ 136 $ 18 $ — $ — (*) Includes operating lease obligations related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $652 million, $59 million, and $952 million, respectively, at December 31, 2022 and $802 million, $104 million, and $1.11 billion, respectively, at December 31, 2021.
Lease costs and other information	Lease costs for 2022, 2021, and 2020, which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2022 Lease cost Operating lease cost (*) $ 297 $ 59 $ 198 $ 5 $ 32 $ 15 Finance lease cost: Amortization of ROU assets 23 1 15 1 — — Interest on lease obligations 13 — 17 1 — — Total finance lease cost 36 1 32 2 — — Short-term lease costs 64 44 13 — — — Variable lease cost 125 13 105 — 5 — Sublease income (1) — — — — — Total lease cost $ 521 $ 117 $ 348 $ 7 $ 37 $ 15 2021 Lease cost Operating lease cost (*) $ 313 $ 58 $ 208 $ 2 $ 33 $ 19 Finance lease cost: Amortization of ROU assets 21 1 11 1 — — Interest on lease obligations 11 — 16 1 — — Total finance lease cost 32 1 27 2 — — Short-term lease costs 48 15 24 — — — Variable lease cost 96 4 83 — 5 — Sublease income 1 — — — — — Total lease cost $ 490 $ 78 $ 342 $ 4 $ 38 $ 19 2020 Lease cost Operating lease cost (*) $ 309 $ 55 $ 212 $ 3 $ 29 $ 19 Finance lease cost: Amortization of ROU assets 26 1 15 — — — Interest on lease obligations 11 — 16 — — — Total finance lease cost 37 1 31 — — — Short-term lease costs 39 11 26 — — — Variable lease cost 91 4 76 — 7 — Sublease income — (1) — — — — Total lease cost $ 476 $ 70 $ 345 $ 3 $ 36 $ 19 (*) Includes operating lease costs related to PPAs at Southern Company, Alabama Power, and Georgia Power totaling $162 million, $48 million, and $180 million, respectively, in 2022, $165 million, $47 million, and $184 million, respectively, in 2021, and $161 million, $43 million, and $184 million, respectively, in 2020. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) 2022 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 303 $ 58 $ 206 $ 5 $ 30 $ 14 Operating cash flows from finance leases 11 — 20 1 — — Financing cash flows from finance leases 16 1 10 1 — — ROU assets obtained under operating leases 56 10 17 9 — 3 Reassessment of ROU assets under operating leases 16 — — — 16 — ROU assets obtained under finance leases 118 2 116 — — — 2021 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 308 $ 58 $ 211 $ 2 $ 28 $ 19 Operating cash flows from finance leases 9 — 17 1 — — Financing cash flows from finance leases 17 1 9 1 — — ROU assets obtained under operating leases 64 3 9 — 72 7 ROU assets obtained under finance leases 3 — — — — — 2020 Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 310 $ 55 $ 215 $ 3 $ 28 $ 18 Operating cash flows from finance leases 9 — 18 — — — Financing cash flows from finance leases 22 1 11 — — — ROU assets obtained under operating leases 227 63 32 — 51 4 ROU assets obtained under finance leases 10 2 — — — — Southern Alabama Georgia Mississippi Southern Power Southern Company Gas At December 31, 2022 Weighted-average remaining lease term in years: Operating leases 17.3 13.0 8.1 4.7 34.0 11.0 Finance leases 17.4 6.4 11.8 12.9 N/A N/A Weighted-average discount rate: Operating leases 4.51 % 4.87 % 4.52 % 3.49 % 4.86 % 3.79 % Finance leases 4.87 % 3.00 % 8.06 % 2.74 % N/A N/A At December 31, 2021 Weighted-average remaining lease term in years: Operating leases 15.9 9.1 8.7 6.1 32.8 10.5 Finance leases 18.0 8.7 8.5 13.9 N/A N/A Weighted-average discount rate: Operating leases 4.41 % 4.37 % 4.45 % 2.74 % 5.20 % 3.61 % Finance leases 4.82 % 3.09 % 10.81 % 2.74 % N/A N/A
Maturities of operating lease liabilities	Maturities of lease liabilities are as follows: At December 31, 2022 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2023 $ 248 $ 12 $ 191 $ 4 $ 36 $ 11 2024 201 10 165 2 28 11 2025 181 9 138 2 28 11 2026 159 6 135 1 28 8 2027 143 5 135 — 29 3 Thereafter 1,497 64 440 1 1,009 31 Total 2,429 106 1,204 10 1,158 75 Less: Present value discount 844 30 202 1 616 15 Operating lease obligations $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance leases: 2023 $ 33 $ 2 $ 35 $ 2 $ — $ — 2024 22 1 27 2 — — 2025 26 1 35 2 — — 2026 26 1 36 2 — — 2027 26 — 36 2 — — Thereafter 345 — 187 10 — — Total 478 5 356 20 — — Less: Present value discount 164 — 118 3 — — Finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ —
Maturities of finance lease liabilities	Maturities of lease liabilities are as follows: At December 31, 2022 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2023 $ 248 $ 12 $ 191 $ 4 $ 36 $ 11 2024 201 10 165 2 28 11 2025 181 9 138 2 28 11 2026 159 6 135 1 28 8 2027 143 5 135 — 29 3 Thereafter 1,497 64 440 1 1,009 31 Total 2,429 106 1,204 10 1,158 75 Less: Present value discount 844 30 202 1 616 15 Operating lease obligations $ 1,585 $ 76 $ 1,002 $ 9 $ 542 $ 60 Finance leases: 2023 $ 33 $ 2 $ 35 $ 2 $ — $ — 2024 22 1 27 2 — — 2025 26 1 35 2 — — 2026 26 1 36 2 — — 2027 26 — 36 2 — — Thereafter 345 — 187 10 — — Total 478 5 356 20 — — Less: Present value discount 164 — 118 3 — — Finance lease obligations $ 314 $ 5 $ 238 $ 17 $ — $ —
Lease income, operating leases	Lease income for 2022, 2021, and 2020, is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) 2022 Lease income - interest income on sales-type leases $ 25 $ — $ — $ 15 $ 10 $ — Lease income - operating leases 208 77 32 2 85 36 Variable lease income 417 1 — — 448 — Total lease income $ 650 $ 78 $ 32 $ 17 $ 543 $ 36 2021 Lease income - interest income on sales-type leases $ 15 $ — $ — $ 14 $ 1 $ — Lease income - operating leases 223 82 42 2 85 35 Variable lease income 429 — — — 456 — Total lease income $ 667 $ 82 $ 42 $ 16 $ 542 $ 35 2020 Lease income - interest income on sales-type leases $ 16 $ — $ — $ 12 $ — $ — Lease income - operating leases 208 45 58 2 87 35 Variable lease income 419 — — — 449 — Total lease income $ 643 $ 45 $ 58 $ 14 $ 536 $ 35
Lease income, sales-type leases and Power Purchase Agreements	Lease income for 2022, 2021, and 2020, is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) 2022 Lease income - interest income on sales-type leases $ 25 $ — $ — $ 15 $ 10 $ — Lease income - operating leases 208 77 32 2 85 36 Variable lease income 417 1 — — 448 — Total lease income $ 650 $ 78 $ 32 $ 17 $ 543 $ 36 2021 Lease income - interest income on sales-type leases $ 15 $ — $ — $ 14 $ 1 $ — Lease income - operating leases 223 82 42 2 85 35 Variable lease income 429 — — — 456 — Total lease income $ 667 $ 82 $ 42 $ 16 $ 542 $ 35 2020 Lease income - interest income on sales-type leases $ 16 $ — $ — $ 12 $ — $ — Lease income - operating leases 208 45 58 2 87 35 Variable lease income 419 — — — 449 — Total lease income $ 643 $ 45 $ 58 $ 14 $ 536 $ 35
Undiscounted cash flows to be received under tolling arrangements accounted for as sales-type leases	The undiscounted cash flows expected to be received for in-service leased assets under the leases are as follows: At December 31, 2022 Southern Company Mississippi Power Southern (in millions) 2023 $ 39 $ 24 $ 15 2024 38 23 15 2025 37 22 15 2026 36 21 15 2027 35 20 15 Thereafter 364 164 200 Total undiscounted cash flows $ 549 $ 274 $ 275 Net investment in sales-type lease (*) 326 157 169 Difference between undiscounted cash flows and discounted cash flows $ 223 $ 117 $ 106 (*) For Mississippi Power, included in other current assets and other property and investments on the balance sheets. For Southern Power, included in other current assets ($15 million and $12 million at December 31, 2022 and 2021, respectively) and net investment in sales-type leases ($154 million and $161 million at December 31, 2022 and 2021, respectively) on the balance sheet.
Undiscounted cash flows to be received under PPAs accounted for as operating leases	The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases are as follows: At December 31, 2022 Southern Alabama Southern Southern Company Gas (in millions) 2023 $ 145 $ 34 $ 88 $ 36 2024 114 6 90 34 2025 105 5 74 29 2026 104 3 73 29 2027 104 3 74 28 Thereafter 796 23 166 382 Total $ 1,368 $ 74 $ 565 $ 538
Summary of the components of income from leveraged leases	The following table provides a summary of the components of income related to leveraged lease investments. Income was impacted in 2021 and 2020 by the impairment charges discussed below and in Note 15 under "Southern Company." Income in 2021 does not include the impacts of the sale and terminations of leveraged lease projects discussed in Note 15 under "Southern Company." 2021 2020 (in millions) Pretax leveraged lease income (loss) $ 17 $ (180) Income tax benefit (expense) (5) 98 Net leveraged lease income (loss) $ 12 $ (82)

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2022
Income Tax Disclosure [Abstract]
Details of income tax provisions	Details of income tax provisions are as follows: 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Federal — Current $ 10 $ 54 $ 38 $ 42 $ (43) $ 122 Deferred 455 259 152 (16) 56 (3) 465 313 190 26 13 119 State — Current 27 14 (21) — 2 42 Deferred 303 96 201 11 5 19 330 110 180 11 7 61 Total $ 795 $ 423 $ 370 $ 37 $ 20 $ 180 2021 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Federal — Current $ 50 $ 104 $ 311 $ 25 $ (340) $ 85 Deferred 36 172 (449) (15) 343 35 86 276 (138) 10 3 120 State — Current (25) 23 71 — (16) (68) Deferred 206 73 (101) 11 — 223 181 96 (30) 11 (16) 155 Total $ 267 $ 372 $ (168) $ 21 $ (13) $ 275 2020 Southern Company Alabama Power Georgia Mississippi Southern Power Southern Company Gas (in millions) Federal — Current $ 199 $ 198 $ 365 $ 18 $ (303) $ 82 Deferred 70 44 (224) (14) 299 53 269 242 141 4 (4) 135 State — Current 100 61 60 — (4) 35 Deferred 24 34 (49) 10 11 3 124 95 11 10 7 38 Total $ 393 $ 337 $ 152 $ 14 $ 3 $ 173
Summary of amortization of tax credits	ITCs amortized in 2022, 2021, and 2020 were immaterial for the traditional electric operating companies and Southern Company Gas and were as follows for Southern Company and Southern Power: Southern Company Southern Power (in millions) 2022 $ 83 $ 58 2021 84 58 2020 84 59
Schedule of effective income tax reconciliation	A reconciliation of the federal statutory income tax rate to the effective income tax rate is as follows: 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Federal statutory rate 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % State income tax, net of federal deduction 6.2 4.8 6.5 4.4 1.9 6.4 Employee stock plans' dividend deduction (0.5) — — — — — Non-deductible book depreciation 0.6 0.5 0.6 0.3 — — Flowback of excess deferred income taxes (6.6) (1.9) (9.6) (7.8) — (2.5) AFUDC-Equity (1.1) (0.8) (1.5) — — — Federal PTCs — — — — (6.6) — ITC amortization (1.3) (0.1) (0.1) — (17.2) (0.1) Noncontrolling interests 0.5 — — — 8.4 — Other — 0.3 — 0.3 (0.1) (0.9) Effective income tax (benefit) rate 18.8 % 23.8 % 16.9 % 18.2 % 7.4 % 23.9 % 2021 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Federal statutory rate 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % State income tax, net of federal deduction 5.5 4.6 (5.7) 4.9 (8.0) 15.1 Employee stock plans' dividend deduction (0.9) — — — — — Non-deductible book depreciation 0.9 0.5 3.1 0.4 — — Flowback of excess deferred income taxes (11.7) (2.6) (49.9) (15.2) — (2.8) AFUDC-Equity (1.5) (0.7) (6.4) — — — Federal PTCs — — — — (4.6) — ITC amortization (2.2) (0.1) (0.4) — (29.7) (0.1) Noncontrolling interests 0.8 — — — 13.4 — Leveraged lease impairments and dispositions (1.4) — — — — — Other (0.1) 0.2 (1.9) 0.6 (0.4) 0.6 Effective income tax (benefit) rate 10.4 % 22.9 % (40.2) % 11.7 % (8.3) % 33.8 % 2020 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Federal statutory rate 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % 21.0 % State income tax, net of federal deduction 2.8 5.0 0.5 4.8 2.7 4.0 Employee stock plans' dividend deduction (0.7) — — — — — Non-deductible book depreciation 0.7 0.6 0.8 0.5 — — Flowback of excess deferred income taxes (8.8) (3.1) (12.0) (18.5) — (2.7) AFUDC-Equity (0.8) (0.6) (1.1) (0.1) — — Federal PTCs — — — — (2.5) — ITC amortization (1.6) (0.1) (0.1) (0.1) (22.1) (0.1) Noncontrolling interests — — — — 3.1 — Leveraged lease impairments (1.6) — — — — — Other 0.2 (0.3) (0.3) 0.9 (0.9) 0.5 Effective income tax (benefit) rate 11.2 % 22.5 % 8.8 % 8.5 % 1.3 % 22.7 %
Tax effects between the carrying amounts of assets and liabilities	The tax effects of temporary differences between the carrying amounts of assets and liabilities in the financial statements of the Registrants and their respective tax bases, which give rise to deferred tax assets and liabilities, are as follows: December 31, 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Deferred tax liabilities — Accelerated depreciation $ 9,443 $ 2,564 $ 3,447 $ 338 $ 1,351 $ 1,505 Property basis differences 2,350 1,303 693 179 — 150 Employee benefit obligations 888 284 412 43 11 68 AROs 876 499 324 — — — Under recovered fuel and natural gas costs 805 185 548 40 — 32 Regulatory assets – AROs 2,006 679 1,285 42 — — Employee benefit obligations 677 180 226 30 — 15 Remaining book value of retired assets 400 142 253 5 — — Premium on reacquired debt 66 9 57 — — — Other 555 179 181 40 14 82 Total deferred income tax liabilities 18,066 6,024 7,426 717 1,376 1,852 Deferred tax assets — AROs 2,882 1,178 1,609 42 — — ITC and PTC carryforwards 1,685 12 673 — 794 — Employee benefit obligations 890 198 304 47 9 89 Estimated loss on plants under construction 888 — 888 — — — Other state deferred tax attributes 388 — 12 239 51 7 Federal effect of net state deferred tax liabilities 365 175 88 — 28 92 Other property basis differences 207 — 79 — 109 — State effect of federal deferred taxes 136 136 — — — — Other partnership basis differences 111 — — — 111 — Regulatory liability associated with the Tax Reform Legislation (not subject to normalization) 137 127 — 9 — — Long-term debt fair value adjustment 85 — — — — 85 Other comprehensive losses 72 4 5 — 5 — Other 552 213 186 62 17 28 Total deferred income tax assets 8,398 2,043 3,844 399 1,124 301 Valuation allowance (257) — (125) (41) (27) (9) Net deferred income tax assets 8,141 2,043 3,719 358 1,097 292 Net deferred income taxes (assets)/liabilities $ 9,925 $ 3,981 $ 3,707 $ 359 $ 279 $ 1,560 Recognized in the balance sheets: Accumulated deferred income taxes – assets $ (111) $ — $ — $ (107) $ — $ — Accumulated deferred income taxes – liabilities $ 10,036 $ 3,981 $ 3,707 $ 466 $ 279 $ 1,560 December 31, 2021 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Deferred tax liabilities — Accelerated depreciation $ 9,300 $ 2,541 $ 3,340 $ 330 $ 1,421 $ 1,428 Property basis differences 2,301 1,182 781 169 — 148 Federal effect of net state deferred tax assets — — — 22 — — Leveraged lease basis differences 61 — — — — — Employee benefit obligations 820 268 382 41 11 57 AROs 868 329 494 — — — Under recovered fuel and natural gas costs 315 47 109 15 — 144 Regulatory assets – AROs 2,232 863 1,325 44 — — Storm damage reserves 18 — 18 — — — Employee benefit obligations 825 205 256 38 — 15 Remaining book value of retired assets 271 145 121 5 — — Premium on reacquired debt 72 10 62 — — — Other 368 147 77 34 14 82 Total deferred income tax liabilities 17,451 5,737 6,965 698 1,446 1,874 Deferred tax assets — AROs 3,100 1,192 1,819 44 — — ITC and PTC carryforwards 1,750 12 704 — 827 — Employee benefit obligations 1,035 225 342 57 7 77 Estimated loss on plants under construction 825 — 825 — — — Other state deferred tax attributes 361 — 11 246 52 5 Federal effect of net state deferred tax liabilities 305 165 41 — 27 93 Other property basis differences 231 — 90 — 121 — State effect of federal deferred taxes 135 135 — — — — Other partnership basis differences 160 — — — 160 — Regulatory liability associated with the Tax Reform Legislation (not subject to normalization) 268 237 19 12 — — Long-term debt fair value adjustment 91 — — — — 91 Other comprehensive losses 92 5 15 — 11 — Other 561 193 153 34 53 62 Total deferred income tax assets 8,914 2,164 4,019 393 1,258 328 Valuation allowance (207) — (73) (41) (27) (9) Net deferred income tax assets 8,707 2,164 3,946 352 1,231 319 Net deferred income taxes (assets)/liabilities $ 8,744 $ 3,573 $ 3,019 $ 346 $ 215 $ 1,555 Recognized in the balance sheets: Accumulated deferred income taxes – assets $ (118) $ — $ — $ (118) $ — $ — Accumulated deferred income taxes – liabilities $ 8,862 $ 3,573 $ 3,019 $ 464 $ 215 $ 1,555
Summary of tax credit carryforwards	Federal ITC/PTC carryforwards at December 31, 2022 were as follows: Southern Company Alabama Georgia Southern (in millions) Federal ITC/PTC carryforwards $ 1,148 $ 12 $ 135 $ 794 Tax year in which federal ITC/PTC carryforwards begin expiring 2031 2032 2031 2035 Year by which federal ITC/PTC carryforwards are expected to be utilized 2026 2025 2025 2026
Summary of operating loss carryforward	At December 31, 2022, the net state income tax benefit of state and local NOL carryforwards for Southern Company's subsidiaries were as follows: Company/Jurisdiction Approximate Net State Income Tax Benefit of NOL Carryforwards Tax Year NOL (in millions) Mississippi Power Mississippi $ 189 2031 Southern Power Oklahoma 27 2035 Florida 10 2034 Other states 3 Various Southern Power Total $ 40 Other (*) Georgia 23 2042 New York 11 2036 New York City 14 2036 Other states 21 Various Southern Company Total $ 298 (*) Represents other non-registrant Southern Company subsidiaries. Alabama Power, Georgia Power, and Southern Company Gas did not have material state or local NOL carryforwards at December 31, 2022.
Changes in unrecognized tax benefits	Changes in unrecognized tax benefits for the periods presented were as follows: Southern Company Southern (in millions) Unrecognized tax benefits at December 31, 2019 $ — $ — Tax positions changes – increase from prior periods 44 — Unrecognized tax benefits at December 31, 2020 $ 44 $ — Tax positions changes – increase from prior periods 3 — Unrecognized tax benefits at December 31, 2021 $ 47 $ — Tax positions changes – increase from prior periods 33 32 Unrecognized tax benefits at December 31, 2022 $ 80 $ 32

RETIREMENT BENEFITS (Tables)

RETIREMENT BENEFITS (Tables)	12 Months Ended
	Dec. 31, 2022
Retirement Benefits [Abstract]
Summary of actuarial assumptions	The weighted average rates assumed in the actuarial calculations used to determine both the net periodic costs for the pension and other postretirement benefit plans for the following year and the benefit obligations as of the measurement date are presented below. 2022 Assumptions used to determine net Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate – benefit obligations 3.09 % 3.12 % 3.07 % 3.07 % 3.21 % 3.04 % Discount rate – interest costs 2.55 2.58 2.51 2.54 2.79 2.53 Discount rate – service costs 3.34 3.36 3.37 3.35 3.36 3.21 Expected long-term return on plan assets 8.25 8.25 8.25 8.25 8.25 8.25 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate – benefit obligations 2.90 % 2.95 % 2.87 % 2.88 % 3.07 % 2.82 % Discount rate – interest costs 2.32 2.38 2.30 2.27 2.55 2.17 Discount rate – service costs 3.26 3.30 3.27 3.26 3.25 3.22 Expected long-term return on plan assets 7.21 7.54 6.88 7.22 — 6.08 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 2021 Assumptions used to determine net Southern Company Alabama Georgia Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate – benefit obligations 2.81 % 2.85 % 2.79 % 2.80 % 2.99 % 2.75 % Discount rate – interest costs 2.13 2.17 2.09 2.12 2.46 2.10 Discount rate – service costs 3.18 3.23 3.21 3.20 3.22 2.97 Expected long-term return on plan assets 8.25 8.25 8.25 8.25 8.25 8.25 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate – benefit obligations 2.56 % 2.63 % 2.52 % 2.53 % 2.78 % 2.46 % Discount rate – interest costs 1.84 1.91 1.82 1.78 2.12 1.64 Discount rate – service costs 3.07 3.13 3.08 3.06 3.05 3.01 Expected long-term return on plan assets 7.09 7.18 6.84 6.98 — 6.54 Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 2020 Assumptions used to determine net periodic costs: Southern Company Alabama Georgia Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate – benefit obligations 3.41 % 3.44 % 3.40 % 3.41 % 3.52 % 3.39 % Discount rate – interest costs 2.99 3.01 2.96 2.99 3.18 2.99 Discount rate – service costs 3.66 3.69 3.67 3.67 3.70 3.53 Expected long-term return on plan assets 8.25 8.25 8.25 8.25 8.25 8.25 Annual salary increase 4.73 4.73 4.73 4.73 4.73 4.73 Other postretirement benefit plans Discount rate – benefit obligations 3.24 % 3.28 % 3.22 % 3.22 % 3.39 % 3.19 % Discount rate – interest costs 2.80 2.84 2.79 2.76 2.97 2.71 Discount rate – service costs 3.57 3.61 3.57 3.57 3.57 3.52 Expected long-term return on plan assets 7.25 7.36 7.05 7.07 — 6.69 Annual salary increase 4.73 4.73 4.73 4.73 4.73 4.73 2022 Assumptions used to determine benefit obligations: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate 5.25 % 5.26 % 5.25 % 5.25 % 5.31 % 5.24 % Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate 5.18 % 5.20 % 5.17 % 5.17 % 5.24 % 5.16 % Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 2021 Assumptions used to determine benefit obligations: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Pension plans Discount rate 3.09 % 3.12 % 3.07 % 3.07 % 3.21 % 3.04 % Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80 Other postretirement benefit plans Discount rate 2.90 % 2.95 % 2.87 % 2.88 % 3.07 % 2.82 % Annual salary increase 4.80 4.80 4.80 4.80 4.80 4.80
Schedule of health care cost trend rates	The weighted average medical care cost trend rates used in measuring the APBO for the Registrants at December 31, 2022 were as follows: Initial Cost Trend Rate Ultimate Cost Trend Rate Year That Ultimate Rate is Reached Pre-65 6.60 % 4.50 % 2030 Post-65 medical 5.50 4.50 2030 Post-65 prescription 7.50 4.50 2031
Schedule of accumulated and projected benefit obligations	The total accumulated benefit obligation for the pension plans at December 31, 2022 and 2021 was as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) December 31, 2022 $ 11,422 $ 2,601 $ 3,534 $ 520 $ 135 $ 801 December 31, 2021 14,687 3,362 4,562 672 178 1,030 The projected benefit obligations for the qualified and non-qualified pension plans at December 31, 2022 are shown in the following table. All pension plan assets are related to the qualified pension plan. Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Projected benefit obligations: Qualified pension plan $ 11,928 $ 2,799 $ 3,717 $ 540 $ 140 $ 819 Non-qualified pension plan 674 107 134 28 23 49
Changes in projected benefit obligations and fair value of plan assets	Changes in the projected benefit obligations and the fair value of plan assets during the plan years ended December 31, 2022 and 2021 were as follows: 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 16,382 $ 3,806 $ 5,012 $ 743 $ 222 $ 1,134 Service cost 412 99 103 17 9 34 Interest cost 408 96 123 18 6 28 Benefits paid (692) (144) (226) (30) (5) (75) Actuarial gain (3,908) (951) (1,161) (179) (69) (253) Balance at end of year 12,602 2,906 3,851 569 163 868 Change in plan assets Fair value of plan assets at beginning of year 17,225 4,141 5,415 786 213 1,241 Actual loss on plan assets (2,376) (579) (753) (110) (31) (167) Employer contributions 61 9 20 3 1 3 Benefits paid (692) (144) (226) (30) (5) (75) Fair value of plan assets at end of year 14,218 3,427 4,456 649 178 1,002 Accrued asset $ 1,616 $ 521 $ 605 $ 80 $ 15 $ 134 2021 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 16,646 $ 3,854 $ 5,127 $ 754 $ 217 $ 1,189 Service cost 434 102 112 18 10 37 Interest cost 346 82 104 16 5 24 Benefits paid (651) (137) (210) (28) (4) (73) Actuarial gain (393) (95) (121) (17) (6) (43) Balance at end of year 16,382 3,806 5,012 743 222 1,134 Change in plan assets Fair value of plan assets at beginning of year 15,367 3,684 4,844 701 186 1,123 Actual return on plan assets 2,449 586 781 111 30 181 Employer contributions 60 8 — 2 1 10 Benefits paid (651) (137) (210) (28) (4) (73) Fair value of plan assets at end of year 17,225 4,141 5,415 786 213 1,241 Accrued asset (liability) $ 843 $ 335 $ 403 $ 43 $ (9) $ 107
Amounts recognized in balance sheets	Amounts recognized in the balance sheets at December 31, 2022 and 2021 related to the Registrants' pension plans consist of the following: Southern Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) December 31, 2022: Prepaid pension costs (a) $ 2,290 $ 629 $ 738 $ 108 $ 37 $ 183 Other regulatory assets, deferred (b) 2,455 679 887 123 — 111 Other current liabilities (56) (10) (12) (2) (2) (3) Employee benefit obligations (c) (618) (98) (121) (26) (20) (42) Other regulatory liabilities, deferred (85) — — — — — AOCI 24 — — — 11 (75) December 31, 2021: Prepaid pension costs (a) $ 1,657 $ 464 $ 563 $ 78 $ 20 $ 175 Other regulatory assets, deferred (b) 2,920 809 971 146 — 91 Other current liabilities (55) (9) (12) (2) (2) (2) Employee benefit obligations (c) (759) (120) (148) (33) (27) (66) Other regulatory liabilities, deferred (119) — — — — — AOCI 100 — — — 35 (45) (a) Included in prepaid pension and other postretirement benefit costs on Alabama Power's balance sheet and other deferred charges and assets on Southern Power's consolidated balance sheet. (b) Amounts for Southern Company exclude regulatory assets of $190 million and $210 million at December 31, 2022 and 2021, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company. (c) Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets. Presented below are the amounts included in regulatory assets at December 31, 2022 and 2021 related to the portion of the defined benefit pension plan attributable to Southern Company, the traditional electric operating companies, and Southern Company Gas that had not yet been recognized in net periodic pension cost. Southern Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Balance at December 31, 2022 Regulatory assets: Prior service cost $ 10 $ 4 $ 7 $ 1 $ (9) Net loss 2,361 675 880 122 66 Regulatory amortization — — — — 54 Total regulatory assets (*) $ 2,371 $ 679 $ 887 $ 123 $ 111 Balance at December 31, 2021 Regulatory assets: Prior service cost $ 11 $ 5 $ 8 $ 1 $ (11) Net loss 2,790 804 963 145 38 Regulatory amortization — — — — 64 Total regulatory assets (*) $ 2,801 $ 809 $ 971 $ 146 $ 91 (*) Amounts for Southern Company exclude regulatory assets of $190 million and $210 million at December 31, 2022 and 2021, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company. Amounts recognized in the balance sheets at December 31, 2022 and 2021 related to the Registrants' other postretirement benefit plans consist of the following: Southern Company Alabama Power Georgia Mississippi Power Southern Southern Company Gas (in millions) December 31, 2022: Prepaid other postretirement benefit costs (a) $ — $ 28 $ — $ — $ — $ — Other regulatory assets, deferred (b) 34 — 19 — — — Other current liabilities (6) — — — (1) — Employee benefit obligations (c) (437) — (146) (35) (8) (66) Other regulatory liabilities, deferred (170) (21) (58) (9) — (58) AOCI (4) — — — — (2) December 31, 2021: Prepaid other postretirement benefit costs (a) $ — $ 49 $ — $ — $ — $ — Other regulatory assets, deferred (b) 97 — 30 2 — — Other current liabilities (5) — — — — — Employee benefit obligations (c) (593) — (206) (47) (11) (94) Other regulatory liabilities, deferred (171) (62) (40) (1) — (34) AOCI — — — — 2 (5) (a) Included in prepaid pension and other postretirement benefit costs on Alabama Power's balance sheet. (b) Amounts for Southern Company exclude regulatory assets of $32 million and $40 million at December 31, 2022 and 2021, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company. (c) Included in other deferred credits and liabilities on Southern Power's consolidated balance sheets. Presented below are the amounts included in net regulatory assets (liabilities) at December 31, 2022 and 2021 related to the other postretirement benefit plans of Southern Company, the traditional electric operating companies, and Southern Company Gas that had not yet been recognized in net periodic other postretirement benefit cost. Southern Company Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Balance at December 31, 2022: Regulatory assets (liabilities): Prior service cost $ 14 $ 4 $ 6 $ 1 $ 1 Net gain (150) (25) (45) (10) (64) Regulatory amortization — — — — 5 Total regulatory assets (liabilities) (*) $ (136) $ (21) $ (39) $ (9) $ (58) Balance at December 31, 2021: Regulatory assets (liabilities): Prior service cost $ 13 $ 3 $ 5 $ 1 $ 1 Net gain (87) (65) (15) — (51) Regulatory amortization — — — — 16 Total regulatory assets (liabilities) (*) $ (74) $ (62) $ (10) $ 1 $ (34) (*) Amounts for Southern Company exclude regulatory assets of $32 million and $40 million at December 31, 2022 and 2021, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company.
Changes in balances of regulatory assets and regulatory liabilities related to defined benefit pension plans	The changes in the balance of regulatory assets related to the portion of the defined benefit pension plan attributable to Southern Company, the traditional electric operating companies, and Southern Company Gas for the years ended December 31, 2022 and 2021 are presented in the following table: Southern Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Regulatory assets (liabilities): (*) Balance at December 31, 2020 $ 4,621 $ 1,286 $ 1,598 $ 235 $ 205 Net gain (1,523) (394) (527) (74) (97) Reclassification adjustments: Amortization of prior service costs (1) (1) (1) — 2 Amortization of net loss (296) (82) (99) (15) (9) Amortization of regulatory assets (*) — — — — (10) Total reclassification adjustments (297) (83) (100) (15) (17) Total change (1,820) (477) (627) (89) (114) Balance at December 31, 2021 $ 2,801 $ 809 $ 971 $ 146 $ 91 Net (gain) loss (183) (67) (9) (12) 27 Reclassification adjustments: Amortization of prior service costs (1) (1) (1) — 2 Amortization of net gain (loss) (246) (62) (74) (11) 1 Amortization of regulatory assets (*) — — — — (10) Total reclassification adjustments (247) (63) (75) (11) (7) Total change (430) (130) (84) (23) 20 Balance at December 31, 2022 $ 2,371 $ 679 $ 887 $ 123 $ 111 (*) Amounts for Southern Company exclude regulatory assets of $190 million and $210 million at December 31, 2022 and 2021, respectively, associated with unamortized amounts in Southern Company Gas' pension plans prior to its acquisition by Southern Company. The changes in the balance of net regulatory assets (liabilities) related to the other postretirement benefit plans for the plan years ended December 31, 2022 and 2021 are presented in the following table: Southern Company Alabama Power Georgia Mississippi Power Southern Company Gas (in millions) Net regulatory assets (liabilities): (*) Balance at December 31, 2020 $ 51 $ (21) $ 47 $ 5 $ (23) Net gain (120) (41) (55) (4) (2) Reclassification adjustments: Amortization of prior service costs 1 — 1 — — Amortization of net loss (6) — (3) — — Amortization of regulatory assets (*) — — — — (9) Total reclassification adjustments (5) — (2) — (9) Total change (125) (41) (57) (4) (11) Balance at December 31, 2021 $ (74) $ (62) $ (10) $ 1 $ (34) Net (gain) loss (64) 41 (27) (10) (13) Reclassification adjustments: Amortization of prior service costs 1 — — — — Amortization of net gain (loss) 1 — (2) — — Amortization of regulatory assets (*) — — — — (11) Total reclassification adjustments 2 — (2) — (11) Total change (62) 41 (29) (10) (24) Balance at December 31, 2022 $ (136) $ (21) $ (39) $ (9) $ (58) (*) Amounts for Southern Company exclude regulatory assets of $32 million and $40 million at December 31, 2022 and 2021, respectively, associated with unamortized amounts in Southern Company Gas' other postretirement benefit plans prior to its acquisition by Southern Company.
Amounts included in AOCI related to defined benefit pension plans	Presented below are the amounts included in AOCI at December 31, 2022 and 2021 related to the portion of the defined benefit pension plan attributable to Southern Company, Southern Power, and Southern Company Gas that had not yet been recognized in net periodic pension cost. Southern Southern Southern Company (in millions) Balance at December 31, 2022 AOCI: Prior service cost $ (2) $ — $ (3) Net (gain) loss 26 11 (72) Total AOCI $ 24 $ 11 $ (75) Balance at December 31, 2021 AOCI: Prior service cost $ (2) $ — $ (3) Net (gain) loss 102 35 (42) Total AOCI $ 100 $ 35 $ (45) Presented below are the amounts included in AOCI at December 31, 2022 and 2021 related to the other postretirement benefit plans of Southern Company, Southern Power, and Southern Company Gas that had not yet been recognized in net periodic other postretirement benefit cost. Southern Southern Southern Company (in millions) Balance at December 31, 2022 AOCI: Prior service cost $ 1 $ — $ — Net (gain) loss (5) — (2) Total AOCI $ (4) $ — $ (2) Balance at December 31, 2021 AOCI: Prior service cost $ 1 $ — $ 1 Net (gain) loss (1) 2 (6) Total AOCI $ — $ 2 $ (5)
Components of OCI related to defined benefit pension plan	The components of OCI related to the portion of the defined benefit pension plan attributable to Southern Company, Southern Power, and Southern Company Gas for the years ended December 31, 2022 and 2021 are presented in the following table: Southern Company Southern Southern Company (in millions) AOCI: Balance at December 31, 2020 $ 245 $ 60 $ 1 Net gain (128) (22) (47) Reclassification adjustments: Amortization of net gain (loss) (17) (3) 1 Total change (145) (25) (46) Balance at December 31, 2021 $ 100 $ 35 $ (45) Net gain (82) (22) (30) Reclassification adjustments: Amortization of net gain (loss) 6 (2) — Total reclassification adjustments 6 (2) — Total change (76) (24) (30) Balance at December 31, 2022 $ 24 $ 11 $ (75) The components of OCI related to the other postretirement benefit plans for the plan years ended December 31, 2022 and 2021 are presented in the following table: Southern Company Southern Southern Company Gas (in millions) AOCI: Balance at December 31, 2020 $ 8 $ 3 $ — Net gain (11) (1) — Reclassification adjustments: Amortization of net gain (loss) 3 — (5) Total change (8) (1) (5) Balance at December 31, 2021 $ — $ 2 $ (5) Net gain (3) (2) — Reclassification adjustments: Amortization of net gain (loss) (1) — 3 Total change (4) (2) 3 Balance at December 31, 2022 $ (4) $ — $ (2)
Components of net periodic benefit cost	Components of net periodic pension cost for the Registrants were as follows: Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) 2022 Service cost $ 412 $ 99 $ 103 $ 17 $ 9 $ 34 Interest cost 408 96 123 18 6 28 Expected return on plan assets (1,265) (306) (399) (57) (15) (91) Recognized net loss 240 62 75 11 2 8 Net amortization — 1 1 — — 15 Prior service cost — — — — — (3) Net periodic pension cost (income) $ (205) $ (48) $ (97) $ (11) $ 2 $ (9) 2021 Service cost $ 434 $ 102 $ 112 $ 18 $ 10 $ 37 Interest cost 346 82 104 16 5 24 Expected return on plan assets (1,191) (287) (375) (55) (14) (86) Recognized net loss 314 82 100 15 3 13 Net amortization 1 1 1 — — 15 Prior service cost — — — — — (3) Net periodic pension cost (income) $ (96) $ (20) $ (58) $ (6) $ 4 $ — 2020 Service cost $ 376 $ 89 $ 96 $ 15 $ 8 $ 33 Interest cost 432 100 133 20 6 31 Expected return on plan assets (1,100) (264) (347) (51) (13) (75) Recognized net loss 269 71 86 13 2 6 Net amortization 1 1 1 — — 15 Prior service cost — — — — — (3) Net periodic pension cost (income) $ (22) $ (3) $ (31) $ (3) $ 3 $ 7 Components of the other postretirement benefit plans' net periodic cost for the Registrants were as follows: Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) 2022 Service cost $ 23 $ 6 $ 6 $ 1 $ — $ 1 Interest cost 42 10 15 2 — 5 Expected return on plan assets (80) (32) (28) (2) 1 (9) Net amortization (1) — 2 — — 6 Net periodic postretirement benefit cost (income) $ (16) $ (16) $ (5) $ 1 $ 1 $ 3 2021 Service cost $ 24 $ 6 $ 7 $ 1 $ — $ 2 Interest cost 35 9 12 1 — 4 Expected return on plan assets (76) (30) (26) (1) 1 (10) Net amortization 2 — 2 — — 6 Net periodic postretirement benefit cost (income) $ (15) $ (15) $ (5) $ 1 $ 1 $ 2 2020 Service cost $ 22 $ 6 $ 6 $ 1 $ 1 $ 2 Interest cost 54 13 20 2 — 7 Expected return on plan assets (72) (29) (26) (1) — (10) Net amortization 1 — 2 — — 6 Net periodic postretirement benefit cost (income) $ 5 $ (10) $ 2 $ 2 $ 1 $ 5
Estimated pension benefit payments	At December 31, 2022, estimated benefit payments were as follows: Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Benefit Payments: 2023 $ 734 $ 155 $ 230 $ 32 $ 6 $ 83 2024 735 160 236 33 7 57 2025 760 167 243 34 7 58 2026 784 173 248 35 7 60 2027 806 178 252 36 8 61 2028 to 2032 4,262 952 1,304 192 43 323 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Benefit payments: 2023 $ 115 $ 25 $ 41 $ 5 $ 1 $ 18 2024 110 24 39 5 1 17 2025 114 26 41 5 1 17 2026 113 26 41 5 1 16 2027 113 26 41 5 1 16 2028 to 2032 551 130 199 22 1 68
Changes in the APBO and the fair value of plan assets	Changes in the APBO and the fair value of the Registrants' plan assets during the plan years ended December 31, 2022 and 2021 were as follows: 2022 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 1,849 $ 440 $ 656 $ 76 $ 11 $ 237 Service cost 23 6 6 1 — 1 Interest cost 42 10 15 2 — 5 Benefits paid (109) (23) (38) (4) (1) (18) Actuarial gain (365) (89) (125) (16) (1) (46) Retiree drug subsidy 1 — — — — — Balance at end of year 1,441 344 514 59 9 179 Change in plan assets Fair value of plan assets at beginning of year 1,251 489 450 29 — 143 Actual loss on plan assets (218) (98) (71) (4) — (25) Employer contributions 73 4 27 3 1 13 Benefits paid (108) (23) (38) (4) (1) (18) Fair value of plan assets at end of year 998 372 368 24 — 113 Accrued asset (liability) $ (443) $ 28 $ (146) $ (35) $ (9) $ (66) 2021 Southern Company Alabama Power Georgia Mississippi Power Southern Power Southern Company Gas (in millions) Change in benefit obligation Benefit obligation at beginning of year $ 1,948 $ 463 $ 699 $ 81 $ 12 $ 248 Service cost 24 6 7 1 — 2 Interest cost 35 9 12 1 — 4 Benefits paid (105) (22) (36) (5) — (18) Actuarial (gain) loss (54) (16) (26) (2) (1) 1 Retiree drug subsidy 1 — — — — — Balance at end of year 1,849 440 656 76 11 237 Change in plan assets Fair value of plan assets at beginning of year 1,158 458 427 27 — 128 Actual return on plan assets 154 55 55 4 — 18 Employer contributions 43 (2) 4 3 — 15 Benefits paid (104) (22) (36) (5) — (18) Fair value of plan assets at end of year 1,251 489 450 29 — 143 Accrued asset (liability) $ (598) $ 49 $ (206) $ (47) $ (11) $ (94)
Summary of investment strategies and benefit plan asset fair values	A description of the major asset classes that the pension and other postretirement benefit plans are comprised of, along with the valuation methods used for fair value measurement, is provided below: Description Valuation Methodology Domestic equity: A mix of large and small capitalization stocks with generally an equal distribution of value and growth attributes, managed both actively and through passive index approaches. International equity: A mix of large and small capitalization growth and value stocks with developed and emerging markets exposure, managed both actively and through fundamental indexing approaches. Domestic and international equities such as common stocks, American depositary receipts, and real estate investment trusts that trade on public exchanges are classified as Level 1 investments and are valued at the closing price in the active market. Equity funds with unpublished prices that are comprised of publicly traded securities (such as commingled/pooled funds) are also valued at the closing price in the active market, but are classified as Level 2. Fixed income: A mix of domestic and international bonds. Investments in fixed income securities, including fixed income pooled funds, are generally classified as Level 2 investments and are valued based on prices reported in the market place. Additionally, the value of fixed income securities takes into consideration certain items such as broker quotes, spreads, yield curves, interest rates, and discount rates that apply to the term of a specific instrument. Trust-owned life insurance (TOLI): Investments of taxable trusts aimed at minimizing the impact of taxes on the portfolio. Investments in TOLI policies are classified as Level 2 investments and are valued based on the underlying investments held in the policy's separate accounts. The underlying assets are equity and fixed income pooled funds that are comprised of Level 1 and Level 2 securities. Real estate: Investments in traditional private market, equity-oriented investments in real properties (indirectly through pooled funds or partnerships) and in publicly traded real estate securities. Special situations: Investments in opportunistic strategies with the objective of diversifying and enhancing returns and exploiting short-term inefficiencies, as well as investments in promising new strategies of a longer-term nature. Private equity: Investments in private partnerships that invest in private or public securities typically through privately-negotiated and/or structured transactions, including leveraged buyouts, venture capital, and distressed debt. Investments in real estate, special situations, and private equity are generally classified as Net Asset Value as a Practical Expedient, since the underlying assets typically do not have publicly available observable inputs. The fund manager values the assets using various inputs and techniques depending on the nature of the underlying investments. Techniques may include purchase multiples for comparable transactions, comparable public company trading multiples, discounted cash flow analysis, prevailing market capitalization rates, recent sales of comparable investments, and independent third-party appraisals. The fair value of partnerships is determined by aggregating the value of the underlying assets less liabilities.
Fair values of plan assets	The fair values, and actual allocations relative to the target allocations, of the Southern Company system's pension plans at December 31, 2022 and 2021 are presented below. Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Equity: 45 % 43 % Domestic equity $ 2,078 $ 691 $ — $ — $ 2,769 International equity 2,166 1,090 — — 3,256 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 1,469 — — 1,469 Mortgage- and asset-backed securities — 29 — — 29 Corporate bonds — 1,494 — — 1,494 Pooled funds — 607 — — 607 Cash equivalents and other 399 7 — — 406 Real estate investments 376 — — 1,887 2,263 13 15 Special situations — — — 187 187 3 2 Private equity — — — 1,717 1,717 9 12 Total $ 5,019 $ 5,387 $ — $ 3,791 $ 14,197 100 % 100 % Liabilities: Derivatives (4) — — — (4) Total $ 5,015 $ 5,387 $ — $ 3,791 $ 14,193 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Alabama Power Assets: Equity: 45 % 43 % Domestic equity $ 500 $ 167 $ — $ — $ 667 International equity 522 263 — — 785 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 354 — — 354 Mortgage- and asset-backed securities — 7 — — 7 Corporate bonds — 360 — — 360 Pooled funds — 146 — — 146 Cash equivalents and other 96 2 — — 98 Real estate investments 91 — — 455 546 13 15 Special situations — — — 45 45 3 2 Private equity — — — 414 414 9 12 Total $ 1,209 $ 1,299 $ — $ 914 $ 3,422 100 % 100 % Liabilities: Derivatives (1) — — — (1) Total $ 1,208 $ 1,299 $ — $ 914 $ 3,421 100 % 100 % Georgia Power Assets: Equity: 45 % 43 % Domestic equity $ 651 $ 217 $ — $ — $ 868 International equity 678 342 — — 1,020 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 460 — — 460 Mortgage- and asset-backed securities — 9 — — 9 Corporate bonds — 468 — — 468 Pooled funds — 190 — — 190 Cash equivalents and other 125 2 — — 127 Real estate investments 118 — — 591 709 13 15 Special situations — — — 59 59 3 2 Private equity — — — 538 538 9 12 Total $ 1,572 $ 1,688 $ — $ 1,188 $ 4,448 100 % 100 % Liabilities: Derivatives (1) — — — (1) Total $ 1,571 $ 1,688 $ — $ 1,188 $ 4,447 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Mississippi Power Assets: Equity: 45 % 43 % Domestic equity $ 95 $ 32 $ — $ — $ 127 International equity 99 50 — — 149 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 67 — — 67 Mortgage- and asset-backed securities — 1 — — 1 Corporate bonds — 68 — — 68 Pooled funds — 28 — — 28 Cash equivalents and other 18 — — — 18 Real estate investments 17 — — 86 103 13 15 Special situations — — — 9 9 3 2 Private equity — — — 78 78 9 12 Total $ 229 $ 246 $ — $ 173 $ 648 100 % 100 % Southern Power Assets: Equity: 45 % 43 % Domestic equity $ 25 $ 9 $ — $ — $ 34 International equity 27 14 — — 41 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 18 — — 18 Corporate bonds — 19 — — 19 Pooled funds — 8 — — 8 Cash equivalents and other 5 — — — 5 Real estate investments 5 — — 24 29 13 15 Special situations — — — 2 2 3 2 Private equity — — — 21 21 9 12 Total $ 62 $ 68 $ — $ 47 $ 177 100% 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Gas Assets: Equity: 45 % 43 % Domestic equity $ 146 $ 49 $ — $ — $ 195 International equity 152 77 — — 229 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 104 — — 104 Mortgage- and asset-backed securities — 2 — — 2 Corporate bonds — 105 — — 105 Pooled funds — 43 — — 43 Cash equivalents and other 28 1 — — 29 Real estate investments 27 — — 133 160 13 15 Special situations — — — 13 13 3 2 Private equity — — — 121 121 9 12 Total $ 353 $ 381 $ — $ 267 $ 1,001 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2021: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Equity: 51 % 53 % Domestic equity $ 3,095 $ 1,326 $ — $ — $ 4,421 International equity 2,740 1,402 3 — 4,145 Fixed income: 23 22 U.S. Treasury, government, and agency bonds — 1,209 — — 1,209 Mortgage- and asset-backed securities — 10 — — 10 Corporate bonds — 1,752 — — 1,752 Pooled funds — 771 — — 771 Cash equivalents and other 405 7 — — 412 Real estate investments 706 — — 2,038 2,744 14 15 Special situations — — — 171 171 3 1 Private equity — — — 1,590 1,590 9 9 Total $ 6,946 $ 6,477 $ 3 $ 3,799 $ 17,225 100 % 100 % Alabama Power Assets: Equity: 51 % 53 % Domestic equity $ 743 $ 319 $ — $ — $ 1,062 International equity 659 337 1 — 997 Fixed income: 23 22 U.S. Treasury, government, and agency bonds — 291 — — 291 Mortgage- and asset-backed securities — 2 — — 2 Corporate bonds — 421 — — 421 Pooled funds — 186 — — 186 Cash equivalents and other 97 2 — — 99 Real estate investments 170 — — 490 660 14 15 Special situations — — — 41 41 3 1 Private equity — — — 382 382 9 9 Total $ 1,669 $ 1,558 $ 1 $ 913 $ 4,141 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2021: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Georgia Power Assets: Equity: 51 % 53 % Domestic equity $ 972 $ 417 $ — $ — $ 1,389 International equity 861 441 1 — 1,303 Fixed income: 23 22 U.S. Treasury, government, and agency bonds — 380 — — 380 Mortgage- and asset-backed securities — 3 — — 3 Corporate bonds — 551 — — 551 Pooled funds — 243 — — 243 Cash equivalents and other 127 2 — — 129 Real estate investments 222 — — 641 863 14 15 Special situations — — — 54 54 3 1 Private equity — — — 500 500 9 9 Total $ 2,182 $ 2,037 $ 1 $ 1,195 $ 5,415 100 % 100 % Mississippi Power Assets: Equity: 51 % 53 % Domestic equity $ 142 $ 61 $ — $ — $ 203 International equity 126 64 — — 190 Fixed income: 23 22 U.S. Treasury, government, and agency bonds — 55 — — 55 Corporate bonds — 80 — — 80 Pooled funds — 35 — — 35 Cash equivalents and other 18 — — — 18 Real estate investments 32 — — 93 125 14 15 Special situations — — — 8 8 3 1 Private equity — — — 73 73 9 9 Total $ 318 $ 295 $ — $ 174 $ 787 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2021: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Power Assets: Equity: 51 % 53 % Domestic equity $ 38 $ 16 $ — $ — $ 54 International equity 34 17 — — 51 Fixed income: 23 22 U.S. Treasury, government, and agency bonds — 15 — — 15 Corporate bonds — 22 — — 22 Pooled funds — 10 — — 10 Cash equivalents and other 5 — — — 5 Real estate investments 9 — — 25 34 14 15 Special situations — — — 2 2 3 1 Private equity — — — 20 20 9 9 Total $ 86 $ 80 $ — $ 47 $ 213 100 % 100 % Southern Company Gas Assets: Equity: 51 % 53 % Domestic equity $ 223 $ 96 $ — $ — $ 319 International equity 197 101 — — 298 Fixed income: 23 22 U.S. Treasury, government, and agency bonds — 87 — — 87 Mortgage- and asset-backed securities — 1 — — 1 Corporate bonds — 126 — — 126 Pooled funds — 56 — — 56 Cash equivalents and other 29 — — — 29 Real estate investments 51 — — 147 198 14 15 Special situations — — — 12 12 3 1 Private equity — — — 115 115 9 9 Total $ 500 $ 467 $ — $ 274 $ 1,241 100 % 100 % The fair values, and actual allocations relative to the target allocations, of the applicable Registrants' other postretirement benefit plan assets at December 31, 2022 and 2021 are presented below. Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Net Asset Value as a Practical Expedient Total Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (NAV) (in millions) Southern Company Assets: Equity: 61 % 59 % Domestic equity $ 85 $ 74 $ — $ 159 International equity 58 79 — 137 Fixed income: 30 28 U.S. Treasury, government, and agency bonds — 43 — 43 Mortgage- and asset-backed securities — 1 — 1 Corporate bonds — 40 — 40 Pooled funds — 79 — 79 Cash equivalents and other 19 — — 19 Trust-owned life insurance — 406 — 406 Real estate investments 11 — 51 62 5 7 Special situations — — 6 6 1 1 Private equity — — 46 46 3 5 Total $ 173 $ 722 $ 103 $ 998 100 % 100 % Alabama Power Assets: Equity: 69 % 65 % Domestic equity $ 17 $ 6 $ — $ 23 International equity 18 9 — 27 Fixed income: 23 23 U.S. Treasury, government, and agency bonds — 12 — 12 Corporate bonds — 12 — 12 Pooled funds — 7 — 7 Cash equivalents and other 3 — — 3 Trust-owned life insurance — 252 — 252 Real estate investments 3 — 16 19 4 7 Special situations — — 2 2 1 1 Private equity — — 14 14 3 4 Total $ 41 $ 298 $ 32 $ 371 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Net Asset Value as a Practical Expedient Total Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (NAV) (in millions) Georgia Power Assets: Equity: 58 % 56 % Domestic equity $ 46 $ 6 $ — $ 52 International equity 17 39 — 56 Fixed income: 35 34 U.S. Treasury, government, and agency bonds — 10 — 10 Corporate bonds — 12 — 12 Pooled funds — 40 — 40 Cash equivalents and other 9 — — 9 Trust-owned life insurance — 154 — 154 Real estate investments 4 — 15 19 4 5 Special situations — — 2 2 1 1 Private equity — — 14 14 2 4 Total $ 76 $ 261 $ 31 $ 368 100 % 100 % Mississippi Power Assets: Equity: 37 % 35 % Domestic equity $ 3 $ 1 $ — $ 4 International equity 3 2 — 5 Fixed income: 43 41 U.S. Treasury, government, and agency bonds — 4 — 4 Corporate bonds — 2 — 2 Pooled funds — 1 — 1 Cash equivalents and other 2 — — 2 Real estate investments 1 — 3 4 11 12 Special situations — — — — 2 2 Private equity — — 2 2 7 10 Total $ 9 $ 10 $ 5 $ 24 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Net Asset Value as a Practical Expedient Total Target Allocation Actual Allocation At December 31, 2022: (Level 1) (Level 2) (NAV) (in millions) Southern Company Gas Assets: Equity: 72 % 70 % Domestic equity $ 2 $ 56 $ — $ 58 International equity 2 20 — 22 Fixed income: 26 27 U.S. Treasury, government, and agency bonds — 1 — 1 Corporate bonds — 1 — 1 Pooled funds — 27 — 27 Cash equivalents and other 1 — — 1 Real estate investments — — 2 2 1 2 Private equity — — 1 1 1 1 Total $ 5 $ 105 $ 3 $ 113 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2021: (Level 1) (Level 2) (NAV) Total (in millions) Southern Company Assets: Equity: 64 % 66 % Domestic equity $ 123 $ 112 $ — $ 235 International equity 73 99 — 172 Fixed income: 27 25 U.S. Treasury, government, and agency bonds — 37 — 37 Corporate bonds — 50 — 50 Pooled funds — 90 — 90 Cash equivalents and other 14 — — 14 Trust-owned life insurance — 530 — 530 Real estate investments 20 — 54 74 5 6 Special situations — — 5 5 1 — Private equity — — 42 42 3 3 Total $ 230 $ 918 $ 101 $ 1,249 100 % 100 % Alabama Power Assets: Equity: 71 % 69 % Domestic equity $ 26 $ 11 $ — $ 37 International equity 23 12 — 35 Fixed income: 21 21 U.S. Treasury, government, and agency bonds — 10 — 10 Corporate bonds — 18 — 18 Pooled funds — 6 — 6 Cash equivalents and other 3 — — 3 Trust-owned life insurance — 341 — 341 Real estate investments 6 — 17 23 4 7 Special situations — — 2 2 1 — Private equity — — 13 13 3 3 Total $ 58 $ 398 $ 32 $ 488 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2021: (Level 1) (Level 2) (NAV) Total (in millions) Georgia Power Assets: Equity: 60 % 62 % Domestic equity $ 65 $ 13 $ — $ 78 International equity 22 50 — 72 Fixed income: 33 30 U.S. Treasury, government, and agency bonds — 9 — 9 Corporate bonds — 14 — 14 Pooled funds — 46 — 46 Cash equivalents and other 5 — — 5 Trust-owned life insurance — 189 — 189 Real estate investments 7 — 16 23 4 5 Special situations — — 1 1 1 — Private equity — — 13 13 2 3 Total $ 99 $ 321 $ 30 $ 450 100 % 100 % Mississippi Power Assets: Equity: 43 % 44 % Domestic equity $ 4 $ 2 $ — $ 6 International equity 4 2 — 6 Fixed income: 36 34 U.S. Treasury, government, and agency bonds — 5 — 5 Corporate bonds — 2 — 2 Pooled funds — 1 — 1 Cash equivalents and other 1 — — 1 Real estate investments 1 — 3 4 11 13 Special situations — — — — 2 1 Private equity — — 2 2 8 8 Total $ 10 $ 12 $ 5 $ 27 100 % 100 % Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Net Asset Value as a Practical Expedient Target Allocation Actual Allocation At December 31, 2021: (Level 1) (Level 2) (NAV) Total (in millions) Southern Company Gas Assets: Equity: 72 % 73 % Domestic equity $ 3 $ 76 $ — $ 79 International equity 2 24 — 26 Fixed income: 26 24 U.S. Treasury, government, and agency bonds — 1 — 1 Corporate bonds — 1 — 1 Pooled funds — 30 — 30 Cash equivalents and other 2 — — 2 Real estate investments 1 — 2 3 1 2 Private equity — — 1 1 1 1 Total $ 8 $ 132 $ 3 $ 143 100 % 100 %
Total matching contributions	Total matching contributions made to the plans for 2022, 2021, and 2020 were as follows: Southern Company Alabama Georgia Mississippi Southern Southern Company Gas (in millions) 2022 $ 124 $ 26 $ 29 $ 5 $ 3 $ 17 2021 119 26 28 5 2 16 2020 120 26 29 5 2 16

STOCK COMPENSATION (Tables)

STOCK COMPENSATION (Tables)	12 Months Ended
	Dec. 31, 2022
Share-Based Payment Arrangement [Abstract]
Schedule of employees participating in stock-based compensation programs	At December 31, 2022, the number of current and former employees participating in stock-based compensation programs for the Registrants was as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Number of employees 1,586 221 236 64 45 186
Assumptions used in the pricing model and the weighted average grant-date fair value of performance share award units granted	The following table shows the assumptions used in the pricing model and the weighted average grant-date fair value of TSR awards granted: Year Ended December 31 2022 2021 2020 Expected volatility 29.6% 30.0% 15.4% Expected term (in years) 3 3 3 Interest rate 1.7% 0.2% 1.4% Weighted average grant-date fair value $79.69 $69.06 $77.65
Schedule of compensation costs and related tax benefits	Total PSU compensation cost, and the related tax benefit recognized in income, for the years ended December 31, 2022, 2021, and 2020 are as follows: 2022 2021 2020 (in millions) Southern Company Compensation cost recognized in income $ 101 $ 112 $ 84 Tax benefit of compensation cost recognized in income 26 29 22 Southern Company Gas Compensation cost recognized in income $ 12 $ 17 $ 13 Tax benefit of compensation cost recognized in income 4 4 4 Total intrinsic value of options exercised, and the related tax benefit, for the years ended December 31, 2022, 2021, and 2020 are presented below for Southern Company and Georgia Power and were immaterial for all other Registrants: Year Ended December 31 2022 2021 2020 (in millions) Southern Company Intrinsic value of options exercised $ 49 $ 34 $ 38 Tax benefit of options exercised 12 7 9 Georgia Power Intrinsic value of options exercised $ 15 $ 14 $ 9 Tax benefit of options exercised 4 3 2
Share-based compensation, stock options, activity	Southern Company's activity in the stock option program for 2022 is summarized below: Shares Subject to Option Weighted Average Exercise Price (in millions) Outstanding at December 31, 2021 2.8 $ 42.95 Exercised 1.8 43.37 Outstanding and Exercisable at December 31, 2022 1.0 $ 42.22

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2022
Fair Value Disclosures [Abstract]
Assets and liabilities measured at fair value on a recurring basis	The fair value increases (decreases) of the Funds, including unrealized gains (losses) and reinvested interest and dividends and excluding the Funds' expenses, for 2022, 2021, and 2020 are shown in the table below. Southern Company Alabama Georgia (in millions) Fair value increases (decreases) 2022 $ (360) $ (171) $ (189) 2021 274 200 74 2020 280 142 138 Unrealized gains (losses) At December 31, 2022 $ (391) $ (204) $ (187) At December 31, 2021 (27) (30) 3 At December 31, 2020 220 121 99 At December 31, 2022, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 18 $ 181 $ — $ — $ 199 Interest rate derivatives — 12 — — 12 Investments in trusts: (b)(c) Domestic equity 651 178 — — 829 Foreign equity 125 150 — — 275 U.S. Treasury and government agency securities — 285 — — 285 Municipal bonds — 51 — — 51 Pooled funds – fixed income — 7 — — 7 Corporate bonds — 412 — — 412 Mortgage and asset backed securities — 90 — — 90 Private equity — — — 161 161 Cash and cash equivalents 4 — — — 4 Other 37 12 — — 49 Cash equivalents 1,427 20 — — 1,447 Other investments 9 26 — — 35 Total $ 2,271 $ 1,424 $ — $ 161 $ 3,856 Liabilities: Energy-related derivatives (a) $ 32 $ 178 $ — $ — $ 210 Interest rate derivatives — 302 — — 302 Foreign currency derivatives — 216 — — 216 Contingent consideration — — 12 — 12 Other — 13 — — 13 Total $ 32 $ 709 $ 12 $ — $ 753 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 62 $ — $ — $ 62 Nuclear decommissioning trusts: (b) Domestic equity 396 169 — — 565 Foreign equity 125 — — — 125 U.S. Treasury and government agency securities — 19 — — 19 Municipal bonds — 1 — — 1 Corporate bonds — 225 — — 225 Mortgage and asset backed securities — 22 — — 22 Private equity — — — 161 161 Other 7 — — — 7 Cash equivalents 438 20 — — 458 Other investments — 26 — — 26 Total $ 966 $ 544 $ — $ 161 $ 1,671 Liabilities: Energy-related derivatives $ — $ 39 $ — $ — $ 39 Georgia Power Assets: Energy-related derivatives $ — $ 42 $ — $ — $ 42 Nuclear decommissioning trusts: (b)(c) Domestic equity 255 1 — — 256 Foreign equity — 149 — — 149 U.S. Treasury and government agency securities — 266 — — 266 Municipal bonds — 50 — — 50 Corporate bonds — 187 — — 187 Mortgage and asset backed securities — 68 — — 68 Other 30 12 — — 42 Cash equivalents 355 — — — 355 Total $ 640 $ 775 $ — $ — $ 1,415 Liabilities: Energy-related derivatives $ — $ 62 $ — $ — $ 62 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2022: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 59 $ — $ — $ 59 Cash equivalents 47 — — — 47 Total $ 47 $ 59 $ — $ — $ 106 Liabilities: Energy-related derivatives $ — $ 32 $ — $ — $ 32 Southern Power Assets: Energy-related derivatives $ — $ 8 $ — $ — $ 8 Liabilities: Energy-related derivatives $ — $ 12 $ — $ — $ 12 Foreign currency derivatives — 47 — — 47 Contingent consideration — — 12 — 12 Other — 13 — — 13 Total $ — $ 72 $ 12 $ — $ 84 Southern Company Gas Assets: Energy-related derivatives (a) $ 18 $ 10 $ — $ — $ 28 Non-qualified deferred compensation trusts: Domestic equity — 8 — — 8 Foreign equity — 1 — — 1 Pooled funds - fixed income — 7 — — 7 Cash and cash equivalents 4 — — — 4 Cash equivalents 50 — — — 50 Total $ 72 $ 26 $ — $ — $ 98 Liabilities: Energy-related derivatives (a)(b) $ 32 $ 33 $ — $ — $ 65 Interest rate derivatives — 86 — — 86 Total $ 32 $ 119 $ — $ — $ 151 (a) Excludes cash collateral of $41 million. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information. (c) Includes investment securities pledged to creditors and collateral received and excludes payables related to the securities lending program. See Note 6 under "Nuclear Decommissioning" for additional information. At December 31, 2021, assets and liabilities measured at fair value on a recurring basis during the period, together with their associated level of the fair value hierarchy, were as follows: Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2021: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 24 $ 195 $ — $ — $ 219 Interest rate derivatives — 19 — — 19 Investments in trusts: (b)(c) Domestic equity 791 225 — — 1,016 Foreign equity 165 188 — — 353 U.S. Treasury and government agency securities — 314 — — 314 Municipal bonds — 56 — — 56 Pooled funds – fixed income — 13 — — 13 Corporate bonds 1 522 — — 523 Mortgage and asset backed securities — 93 — — 93 Private equity — — — 150 150 Cash and cash equivalents 2 — — — 2 Other 22 25 — — 47 Cash equivalents 1,160 14 — — 1,174 Other investments 9 35 — — 44 Total $ 2,174 $ 1,699 $ — $ 150 $ 4,023 Liabilities: Energy-related derivatives (a) $ 10 $ 36 $ — $ — $ 46 Interest rate derivatives — 29 — — 29 Foreign currency derivatives — 79 — — 79 Contingent consideration — — 14 — 14 Other — 13 — — 13 Total $ 10 $ 157 $ 14 $ — $ 181 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2021: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 55 $ — $ — $ 55 Nuclear decommissioning trusts: (b) Domestic equity 468 216 — — 684 Foreign equity 165 — — — 165 U.S. Treasury and government agency securities — 21 — — 21 Municipal bonds — 1 — — 1 Corporate bonds 1 271 — — 272 Mortgage and asset backed securities — 22 — — 22 Private equity — — — 150 150 Other 9 — — — 9 Cash equivalents 839 14 — — 853 Other investments — 35 — — 35 Total $ 1,482 $ 635 $ — $ 150 $ 2,267 Liabilities: Energy-related derivatives $ — $ 11 $ — $ — $ 11 Georgia Power Assets: Energy-related derivatives $ — $ 75 $ — $ — $ 75 Nuclear decommissioning trusts: (b)(c) Domestic equity 323 1 — — 324 Foreign equity — 185 — — 185 U.S. Treasury and government agency securities — 293 — — 293 Municipal bonds — 55 — — 55 Corporate bonds — 251 — — 251 Mortgage and asset backed securities — 71 — — 71 Other 13 25 — — 38 Total $ 336 $ 956 $ — $ — $ 1,292 Liabilities: Energy-related derivatives $ — $ 8 $ — $ — $ 8 Fair Value Measurements Using Quoted Prices in Active Markets for Identical Assets Significant Other Observable Inputs Significant Unobservable Inputs Net Asset Value as a Practical Expedient At December 31, 2021: (Level 1) (Level 2) (Level 3) (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 56 $ — $ — $ 56 Cash equivalents 40 — — — 40 Total $ 40 $ 56 $ — $ — $ 96 Liabilities: Energy-related derivatives $ — $ 5 $ — $ — $ 5 Southern Power Assets: Energy-related derivatives $ — $ 4 $ — $ — $ 4 Liabilities: Foreign currency derivatives $ — $ 16 $ — $ — $ 16 Contingent consideration — — 14 — 14 Other — 13 — — 13 Total $ — $ 29 $ 14 $ — $ 43 Southern Company Gas Assets: Energy-related derivatives (a) $ 24 $ 5 $ — $ — $ 29 Interest rate derivatives — 6 — — 6 Non-qualified deferred compensation trusts: Domestic equity — 8 — — 8 Foreign equity — 3 — — 3 Pooled funds - fixed income — 13 — — 13 Cash equivalents 2 — — — 2 Total $ 26 $ 35 $ — $ — $ 61 Liabilities: Energy-related derivatives (a)(b) $ 10 $ 12 $ — $ — $ 22 Interest rate derivatives — 5 — — 5 Total $ 10 $ 17 $ — $ — $ 27 (a) Excludes immaterial cash collateral. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 under "Nuclear Decommissioning" for additional information. (c) Includes investment securities pledged to creditors and collateral received and excludes payables related to the securities lending program. See Note 6 under "Nuclear Decommissioning" for additional information.
Financial instruments not having carrying amount equal to fair value	At December 31, 2022 and 2021, other financial instruments for which the carrying amount did not equal fair value were as follows: Southern Company (*) Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (*) (in billions) At December 31, 2022: Long-term debt, including securities due within one year: Carrying amount $ 54.6 $ 10.6 $ 14.7 $ 1.5 $ 3.0 $ 7.4 Fair value 48.6 9.2 13.0 1.3 2.8 6.5 At December 31, 2021: Long-term debt, including securities due within one year: Carrying amount $ 52.1 $ 9.7 $ 13.6 $ 1.5 $ 3.7 $ 6.9 Fair value 57.1 10.9 15.1 1.6 4.1 7.8 (*) The long-term debt of Southern Company Gas is recorded at amortized cost, including the fair value adjustments at the effective date of the 2016 merger with Southern Company. Southern Company Gas amortizes the fair value adjustments over the remaining lives of the respective bonds, the latest being through 2043.

DERIVATIVES (Tables)

DERIVATIVES (Tables)	12 Months Ended
	Dec. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of energy-related derivatives	At December 31, 2022, the net volume of energy-related derivative contracts for natural gas positions, together with the longest hedge date over which the respective entity is hedging its exposure to the variability in future cash flows for forecasted transactions and the longest non-hedge date for derivatives not designated as hedges, were as follows: Net Longest Longest (in millions) Southern Company (*) 431 2030 2025 Alabama Power 111 2026 — Georgia Power 125 2026 — Mississippi Power 94 2027 — Southern Power 8 2030 2023 Southern Company Gas (*) 93 2025 2025 (*) Southern Company Gas' derivative instruments include both long and short natural gas positions. A long position is a contract to purchase natural gas and a short position is a contract to sell natural gas. Southern Company Gas' volume represents the net of long natural gas positions of 98 million mmBtu and short natural gas positions of 5 million mmBtu at December 31, 2022, which is also included in Southern Company's total volume. See Note 15 under "Southern Company Gas" for information regarding the sale of Sequent.
Notional amount of interest rate derivatives	At December 31, 2022, the following interest rate derivatives were outstanding: Notional Weighted Average Interest Rate Paid Interest Hedge Fair Value (in millions) (in millions) Cash Flow Hedges of Forecasted Debt Southern Company parent $ 400 3.50% N/A June 2033 $ 12 Fair Value Hedges of Existing Debt Southern Company parent 400 1-month LIBOR + 0.68% 1.75% March 2028 (55) Southern Company parent 1,000 1-month LIBOR + 2.36% 3.70% April 2030 (161) Southern Company Gas 500 1-month LIBOR + 0.38% 1.75% January 2031 (86) Southern Company $ 2,300 $ (290)
Schedule of foreign exchange contracts	At December 31, 2022, the following foreign currency derivatives were outstanding: Pay Notional Pay Rate Receive Notional Receive Rate Hedge Fair Value (in millions) (in millions) (in millions) Cash Flow Hedges of Existing Debt Southern Power $ 564 3.78% € 500 1.85% June 2026 $ (47) Fair Value Hedges of Existing Debt Southern Company parent 1,476 3.39% 1,250 1.88% September 2027 (169) Southern Company $ 2,040 € 1,750 $ (216)
Fair value of energy-related derivatives and interest rate derivatives	At December 31, 2022 and 2021, the fair value of energy-related derivatives, interest rate derivatives, and foreign currency derivatives was reflected in the balance sheets as follows: 2022 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) Southern Company Energy-related derivatives designated as hedging instruments for regulatory purposes Assets from risk management activities/Other current liabilities $ 123 $ 121 $ 129 $ 30 Other deferred charges and assets/Other deferred credits and liabilities 52 44 72 6 Total derivatives designated as hedging instruments for regulatory purposes 175 165 201 36 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Assets from risk management activities/Other current liabilities 3 27 7 5 Other deferred charges and assets/Other deferred credits and liabilities 6 4 1 — Interest rate derivatives: Assets from risk management activities/Other current liabilities 12 62 19 — Other deferred charges and assets/Other deferred credits and liabilities — 240 — 29 Foreign currency derivatives: Assets from risk management activities/Other current liabilities — 34 — 39 Other deferred charges and assets/Other deferred credits and liabilities — 182 — 40 Total derivatives designated as hedging instruments in cash flow and fair value hedges 21 549 27 113 Energy-related derivatives not designated as hedging instruments Assets from risk management activities/Other current liabilities 13 13 9 4 Other deferred charges and assets/Other deferred credits and liabilities 2 1 1 — Total derivatives not designated as hedging instruments 15 14 10 4 Gross amounts recognized 211 728 238 153 Gross amounts offset (a) (70) (111) (25) (28) Net amounts recognized in the Balance Sheets (b) $ 141 $ 617 $ 213 $ 125 2022 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) Alabama Power (c) Energy-related derivatives designated as hedging instruments for regulatory purposes Other current assets/Other current liabilities $ 42 $ 21 $ 30 $ 9 Other deferred charges and assets/Other deferred credits and liabilities 20 18 25 2 Total derivatives designated as hedging instruments for regulatory purposes 62 39 55 11 Gross amounts offset (24) (24) (5) (5) Net amounts recognized in the Balance Sheets $ 38 $ 15 $ 50 $ 6 Georgia Power Energy-related derivatives designated as hedging instruments for regulatory purposes Assets from risk management activities/Other current liabilities $ 36 $ 43 $ 54 $ 6 Other deferred charges and assets/Other deferred credits and liabilities 6 18 21 2 Total derivatives designated as hedging instruments for regulatory purposes 42 61 75 8 Energy-related derivatives not designated as hedging instruments Other deferred charges and assets/Other deferred credits and liabilities — 1 — — Gross amounts recognized 42 62 75 8 Gross amounts offset (21) (21) (8) (8) Net amounts recognized in the Balance Sheets $ 21 $ 41 $ 67 $ — Mississippi Power (c) Energy-related derivatives designated as hedging instruments for regulatory purposes Assets from risk management activities/Other current liabilities $ 33 $ 24 $ 30 $ 3 Other deferred charges and assets/Other deferred credits and liabilities 26 8 26 2 Total derivatives designated as hedging instruments for regulatory purposes 59 32 56 5 Gross amounts offset (17) (17) (4) (4) Net amounts recognized in the Balance Sheets $ 42 $ 15 $ 52 $ 1 2022 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) Southern Power Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Other current assets/Other current liabilities $ — $ 12 $ 2 $ — Other deferred charges and assets/Other deferred credits and liabilities 5 — 1 — Foreign currency derivatives: Other current assets/Other current liabilities — 11 — 16 Other deferred charges and assets/Other deferred credits and liabilities — 36 — — Total derivatives designated as hedging instruments in cash flow and fair value hedges 5 59 3 16 Energy-related derivatives not designated as hedging instruments Other current assets/Other current liabilities 2 — 1 — Other deferred charges and assets/Other deferred credits and liabilities 1 — — — Total derivatives not designated as hedging instruments 3 — 1 — Net amounts recognized in the Balance Sheets $ 8 $ 59 $ 4 $ 16 Southern Company Gas Energy-related derivatives designated as hedging instruments for regulatory purposes Other current assets/Other current liabilities $ 12 $ 33 $ 15 $ 12 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Other current assets/Other current liabilities 3 15 5 5 Other deferred charges and assets/Other deferred credits and liabilities 1 4 — — Interest rate derivatives: Other current assets/Other current liabilities — 14 6 — Other deferred charges and assets/Other deferred credits and liabilities — 72 — 6 Total derivatives designated as hedging instruments in cash flow and fair value hedges 4 105 11 11 Energy-related derivatives not designated as hedging instruments Other current assets/Other current liabilities 11 12 8 4 Other deferred charges and assets/Other deferred credits and liabilities 1 1 1 — Total derivatives not designated as hedging instruments 12 13 9 4 Gross amounts recognized 28 151 35 27 Gross amounts offset (a) — (41) (8) (11) Net amounts recognized in the Balance Sheets (b) $ 28 $ 110 $ 27 $ 16 (a) Gross amounts offset includes cash collateral held on deposit in broker margin accounts of $41 million and $3 million at December 31, 2022 and 2021, respectively. (b) Net amounts of derivative instruments outstanding exclude immaterial premium and intrinsic value associated with weather derivatives for all periods presented. (c) Energy-related derivatives not designated as hedging instruments were immaterial at December 31, 2022 and there were no such instruments at December 31, 2021.
Pre-tax effects on the balance sheets	At December 31, 2022 and 2021, the pre-tax effects of unrealized derivative gains (losses) arising from energy-related derivative instruments designated as regulatory hedging instruments and deferred were as follows: Regulatory Hedge Unrealized Gain (Loss) Recognized in the Balance Sheets Derivative Category and Balance Sheet Southern Alabama Georgia Mississippi Southern Company Gas (in millions) At December 31, 2022: Energy-related derivatives: Other regulatory assets, current $ (71) $ (8) $ (26) $ (13) $ (24) Other regulatory assets, deferred (23) (7) (14) (2) — Other regulatory liabilities, current 72 29 19 22 2 Other regulatory liabilities, deferred 31 9 2 20 — Total energy-related derivative gains (losses) $ 9 $ 23 $ (19) $ 27 $ (22) At December 31, 2021: Energy-related derivatives: Other regulatory assets, current $ (17) $ (6) $ — $ — $ (11) Other regulatory liabilities, current 107 28 48 27 4 Other regulatory liabilities, deferred 65 22 19 24 — Total energy-related derivative gains (losses) $ 155 $ 44 $ 67 $ 51 $ (7)
Pre-tax effects of hedging on AOCI	For the years ended December 31, 2022, 2021, and 2020, the pre-tax effects of cash flow and fair value hedge accounting on AOCI for the applicable Registrants were as follows: Gain (Loss) From Derivatives Recognized in OCI 2022 2021 2020 (in millions) Southern Company Cash flow hedges: Energy-related derivatives $ 3 $ 34 $ (8) Interest rate derivatives 46 5 (26) Foreign currency derivatives (105) (103) 48 Fair value hedges (*) : Foreign currency derivatives (24) (3) — Total $ (80) $ (67) $ 14 Georgia Power Interest rate derivatives $ 31 $ — $ (3) Southern Power Cash flow hedges: Energy-related derivatives $ (15) $ 12 $ (2) Foreign currency derivatives (105) (103) 48 Total $ (120) $ (91) $ 46 Southern Company Gas Cash flow hedges: Energy-related derivatives $ 18 $ 22 $ (6) Interest rate derivatives — — (23) Total $ 18 $ 22 $ (29) (*) Represents amounts excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI.
Pre-tax effect of interest rate and energy related derivatives	The pre-tax effects of cash flow and fair value hedge accounting on income for the years ended December 31, 2022, 2021, and 2020 were as follows: Location and Amount of Gain (Loss) Recognized in Income on Cash Flow and Fair Value Hedging Relationships 2022 2021 2020 (in millions) Southern Company Total cost of natural gas $ 3,004 $ 1,619 $ 972 Gain (loss) on energy-related cash flow hedges (a) 37 17 (8) Total depreciation and amortization 3,663 3,565 3,518 Gain (loss) on energy-related cash flow hedges (a) (5) 9 (3) Total interest expense, net of amounts capitalized (2,022) (1,837) (1,821) Gain (loss) on interest rate cash flow hedges (a) (25) (27) (26) Gain (loss) on foreign currency cash flow hedges (a) (19) (24) (23) Gain (loss) on interest rate fair value hedges (b) (291) (30) 27 Total other income (expense), net 500 456 336 Gain (loss) on foreign currency cash flow hedges (a)(c) (83) (104) 114 Gain (loss) on foreign currency fair value hedges (106) (63) — Amount excluded from effectiveness testing recognized in earnings 24 3 — Southern Power Total depreciation and amortization $ 516 $ 517 $ 494 Gain (loss) on energy-related cash flow hedges (a) (5) 9 (3) Total interest expense, net of amounts capitalized (138) (147) (151) Gain (loss) on foreign currency cash flow hedges (a) (19) (24) (23) Total other income (expense), net 7 10 19 Gain (loss) on foreign currency cash flow hedges (a)(c) (83) (104) 114 Southern Company Gas Total cost of natural gas $ 3,004 $ 1,619 $ 972 Gain (loss) on energy-related cash flow hedges (a) 37 17 (8) Total interest expense, net of amounts capitalized (263) (238) (231) Gain (loss) on interest rate cash flow hedges (a) (4) — — Gain (loss) on interest rate fair value hedges (b) (86) — — (a) Reclassified from AOCI into earnings. (b) For fair value hedges, changes in the fair value of the derivative contracts are generally equal to changes in the fair value of the underlying debt and have no material impact on income. (c) The reclassification from AOCI into other income (expense), net completely offsets currency gains and losses arising from changes in the U.S. currency exchange rates used to record the euro-denominated notes.
Schedule of fair value hedging instruments, statements of financial performance and financial position, location	At December 31, 2022 and 2021, the following amounts were recorded on the balance sheets related to cumulative basis adjustments for fair value hedges: Carrying Amount of Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item Balance Sheet Location of Hedged Items At December 31, 2022 At December 31, 2021 At December 31, 2022 At December 31, 2021 (in millions) (in millions) Southern Company Long-term debt $ (2,927) $ (3,280) $ 282 $ 9 Southern Company Gas Long-term debt $ (415) $ (493) $ 81 $ 2
Pre-tax effect of interest rate and energy related derivatives	The pre-tax effects of energy-related derivatives not designated as hedging instruments on the statements of income of Southern Company and Southern Company Gas for the years ended December 31, 2022, 2021, and 2020 were as follows: Gain (Loss) Derivatives in Non-Designated Hedging Relationships Statements of Income Location 2022 2021 2020 (in millions) Energy-related derivatives Natural gas revenues (*) $ (11) $ (117) $ 134 Cost of natural gas (65) (27) 15 Total derivatives in non-designated hedging relationships $ (76) $ (144) $ 149 (*) Excludes the impact of weather derivatives recorded in natural gas revenues of $(7) million and $9 million for 2022 and 2020, respectively, as they are accounted for based on intrinsic value rather than fair value. There was no weather derivatives impact for 2021.

ACQUISITIONS AND DISPOSITIONS (

ACQUISITIONS AND DISPOSITIONS (Tables)	12 Months Ended
	Dec. 31, 2022
Business Combination and Asset Acquisition [Abstract]
Schedule of asset acquisition	Asset Acquisitions Project Resource Seller Approximate Nameplate Capacity ( MW ) Location Southern COD PPA Asset Acquisitions During 2021 Deuel Harvest (a) Wind Invenergy Renewables LLC 300 Deuel County, SD 100% of Class B February 2021 25 years and 15 years Asset Acquisitions During 2020 Beech Ridge II (b) Wind Invenergy Renewables LLC 56 Greenbrier County, WV 100% of Class A May 12 years (a) In March 2021, Southern Power acquired a controlling interest in the project from Invenergy Renewables LLC and completed a tax equity transaction whereby it sold the Class A membership interests in the project. Southern Power consolidates the project's operating results in its financial statements and the tax equity partner and Invenergy Renewables LLC each own a noncontrolling interest. (b) In May 2020, Southern Power purchased a controlling interest and now consolidates the project's operating results in its financial statements. The Class B member owns the noncontrolling interest.
Schedule of construction projects	Project Resource Approximate Nameplate Capacity ( MW ) Location COD PPA Contract Period Projects Completed During 2022 Garland Solar Storage (a) Battery energy storage 88 Kern County, CA September 2021 through February 2022 (b) 20 years Tranquillity Solar Storage (a) Battery energy storage 72 Fresno County, CA November 2021 through March 2022 (c) 20 years Projects Completed During 2021 Glass Sands (d) Wind 118 Murray County, OK November 2021 12 years Projects Completed During 2020 Skookumchuck (e) Wind 136 Lewis and Thurston Counties, WA November 2020 20 years Reading (f) Wind 200 Osage and Lyon Counties, KS May 2020 12 years (a) In December 2020, Southern Power restructured its ownership of the project, while retaining the controlling interests, by contributing the Class A membership interests to an existing partnership and selling 100% of the Class B membership interests. During 2021, Southern Power further restructured its ownership in the battery energy storage projects and completed tax equity transactions whereby it sold the Class A membership interests in the projects. Southern Power consolidates each project's operating results in its financial statements and the tax equity partner and two other partners each own a noncontrolling interest. (b) The facility has a total capacity of 88 MWs, of which 73 MWs were placed in service in 2021 and 15 MWs were placed in service in February 2022. (c) The facility has a total capacity of 72 MWs, of which 32 MWs were placed in service in 2021 and 40 MWs were placed in service in March 2022. (d) In December 2020, Southern Power purchased 100% of the membership interests of the Glass Sands facility. (e) In November 2020, Southern Power completed a tax equity transaction whereby it received $121 million, resulting in 100% ownership of the Class B membership interests. Southern Power subsequently sold a noncontrolling interest in the Class B membership interests and now retains the controlling ownership interest in the facility. (f) In June 2020, Southern Power completed a tax equity transaction whereby it received $156 million and owns 100% of the Class B membership interests.

SEGMENT AND RELATED INFORMATI_2

SEGMENT AND RELATED INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2022
Segment Reporting [Abstract]
Financial data for business segments	Financial data for business segments and products and services for the years ended December 31, 2022, 2021, and 2020 was as follows: Electric Utilities Traditional Southern Eliminations Total Southern Company Gas All Eliminations Consolidated (in millions) 2022 Operating revenues $ 20,408 $ 3,369 $ (904) $ 22,873 $ 5,962 $ 593 $ (149) $ 29,279 Depreciation and amortization 2,513 516 — 3,029 559 75 — 3,663 Interest income 44 3 — 47 3 16 (7) 59 Earnings from equity method investments — — — — 148 3 — 151 Interest expense 929 138 — 1,067 263 694 (2) 2,022 Income taxes (benefit) 828 20 — 848 180 (233) — 795 Segment net income (loss) (a)(b)(c)(d) 3,318 354 — 3,672 572 (711) (9) 3,524 Goodwill — 2 — 2 5,015 144 — 5,161 Total assets 95,861 13,081 (659) 108,283 24,621 2,665 (678) 134,891 2021 Operating revenues $ 16,614 $ 2,216 $ (530) $ 18,300 $ 4,380 $ 582 $ (149) $ 23,113 Depreciation and amortization 2,436 517 — 2,953 536 76 — 3,565 Interest income 20 1 — 21 — 4 (3) 22 Earnings from equity method investments 1 — — 1 50 24 1 76 Interest expense 821 147 — 968 238 631 — 1,837 Income taxes (benefit) 232 (13) — 219 275 (227) — 267 Segment net income (loss) (a)(b)(e)(f)(g)(h) 1,981 266 — 2,247 539 (384) (9) 2,393 Goodwill — 2 — 2 5,015 263 — 5,280 Total assets 89,051 13,390 (667) 101,774 23,560 2,975 (775) 127,534 2020 Operating revenues $ 15,135 $ 1,733 $ (371) $ 16,497 $ 3,434 $ 596 $ (152) $ 20,375 Depreciation and amortization 2,447 494 — 2,941 500 77 — 3,518 Interest income 26 4 — 30 5 6 (4) 37 Earnings from equity method investments — — — — 141 12 — 153 Interest expense 825 151 — 976 231 614 — 1,821 Income taxes (benefit) 514 3 — 517 173 (297) — 393 Segment net income (loss) (a)(b)(h)(i)(j) 2,877 238 — 3,115 590 (592) 6 3,119 Goodwill — 2 — 2 5,015 263 — 5,280 Total assets 85,486 13,235 (680) 98,041 22,630 3,168 (904) 122,935 (a) Attributable to Southern Company. (b) For the traditional electric operating companies, includes pre-tax charges to income at Georgia Power for the estimated probable loss associated with the construction of Plant Vogtle Units 3 and 4 of $183 million ($137 million after tax) in 2022, $1.7 billion ($1.3 billion after tax) in 2021, and $325 million ($242 million after tax) in 2020. See Note 2 under "Georgia Power – Nuclear Construction" for additional information. (c) For Southern Company Gas, includes pre-tax impairment charges totaling approximately $131 million ($99 million after tax) related to the sale of natural gas storage facilities. See Note 15 under "Southern Company Gas" for additional information. (d) For the "All Other" column, includes a $119 million goodwill impairment loss (pre-tax and after tax) at PowerSecure. See Note 1 under "Goodwill and Other Intangible Assets and Liabilities" for additional information. (e) For Southern Power, includes gains on wind turbine equipment contributed to various equity method investments totaling approximately $37 million pre-tax ($28 million after tax). See Notes 7 and 15 under "Southern Power" for additional information. (f) For Southern Company Gas, includes a pre-tax gain of $121 million ($92 million after tax) related to its sale of Sequent, as well as the resulting $85 million of additional tax expense due to changes in state apportionment rates, and pre-tax impairment charges totaling $84 million ($67 million after tax) related to its equity method investment in the PennEast Pipeline project. See Notes 7 and 15 under "Southern Company Gas" for additional information. (g) For the "All Other" column, includes a pre-tax gain of $93 million ($99 million gain after tax) associated with the termination of two leveraged leases projects. See Note 15 under "Southern Company" for additional information. (h) For the "All Other" column, includes pre-tax impairment charges totaling $7 million ($6 million after tax) in 2021 and $206 million ($105 million after tax) in 2020 related to leveraged lease investments. See Notes 9 and 15 under "Southern Company Leveraged Lease" and "Southern Company," respectively, for additional information. (i) For Southern Power, includes a $39 million pre-tax gain ($23 million gain after tax) on the sale of Plant Mankato. See Note 15 under "Southern Power" for additional information. (j) For Southern Company Gas, includes a $22 million pre-tax gain ($16 million gain after tax) on the sale of Jefferson Island. See Note 15 under "Southern Company Gas" for additional information. Financial data for business segments for the years ended December 31, 2022, 2021, and 2020 was as follows: Gas Distribution Operations Gas Pipeline Investments Wholesale Gas Services (a) Gas Marketing Services Total All Other Eliminations Consolidated (in millions) 2022 Operating revenues $ 5,267 $ 32 $ — $ 638 $ 5,937 $ 55 $ (30) $ 5,962 Depreciation and amortization 516 5 — 16 537 22 — 559 Operating income (loss) 803 21 — 133 957 (135) (8) 814 Earnings from equity method investments — 148 — — 148 — — 148 Interest expense 229 27 — 3 259 4 — 263 Income taxes (benefit) 145 35 — 37 217 (37) — 180 Segment net income (loss) (b) 470 107 — 94 671 (99) — 572 Total assets 22,040 1,577 — 1,616 25,233 8,943 (9,555) 24,621 2021 Operating revenues $ 3,679 $ 32 $ 188 $ 475 $ 4,374 $ 38 $ (32) $ 4,380 Depreciation and amortization 482 5 — 18 505 31 — 536 Operating income (loss) 708 21 241 125 1,095 (40) — 1,055 Earnings from equity method investments — 50 — — 50 — — 50 Interest expense 207 25 2 3 237 1 — 238 Income taxes (benefit) 120 27 32 34 213 62 — 275 Segment net income (loss) (c)(d)(e) 412 19 107 88 626 (87) — 539 Total assets 20,917 1,467 31 1,556 23,971 12,114 (12,525) 23,560 2020 Operating revenues $ 2,952 $ 32 $ 74 $ 408 $ 3,466 $ 36 $ (68) $ 3,434 Depreciation and amortization 442 5 1 22 470 30 — 500 Operating income (loss) 655 20 20 119 814 (7) 5 812 Earnings from equity method investments — 141 — — 141 — — 141 Interest expense 192 29 4 3 228 3 — 231 Income taxes (benefit) 114 33 3 28 178 (5) — 173 Segment net income (loss) (f) 390 99 14 89 592 (2) — 590 Total assets 19,090 1,597 850 1,503 23,040 11,336 (11,746) 22,630 (a) As a result of the sale of Sequent, wholesale gas services is no longer a reportable segment in 2022. Prior to the sale of Sequent, the revenues for wholesale gas services were netted with costs associated with its energy and risk management activities. A reconciliation of operating revenues and intercompany revenues is shown in the following table. Third Party Gross Revenues Intercompany Revenues Total Gross Revenues Less Gross Gas Costs Operating Revenues (in millions) 2021 $ 3,881 $ 90 $ 3,971 $ 3,783 $ 188 2020 4,544 115 4,659 4,585 74 (b) For the "All Other" column, includes pre-tax impairment charges totaling approximately $131 million ($99 million after tax) related to the sale of natural gas storage facilities. See Note 15 under "Southern Company Gas" for additional information. (c) For gas pipeline investments, includes pre-tax impairment charges totaling $84 million ($67 million after tax) related to the equity method investment in the PennEast Pipeline project. See Note 7 under "Southern Company Gas" for additional information. (d) For wholesale gas services, includes a pre-tax gain of $121 million ($92 million after tax) related to the sale of Sequent. (e) For the "All Other" column, includes $85 million of additional tax expense as a result of the sale of Sequent. (f) For the "All Other" column include s a $22 million pre-tax gain ($16 million g ain after tax) on the sale of Jefferson Island.
Financial data for products and services	Products and Services Electric Utilities' Revenues Year Retail Wholesale Other Total (in millions) 2022 $ 18,197 $ 3,641 $ 1,035 $ 22,873 2021 14,852 2,455 993 18,300 2020 13,643 1,945 909 16,497 Southern Company Gas' Revenues Year Gas Gas All Other Total (in millions) 2022 $ 5,240 $ 638 $ 84 $ 5,962 2021 3,656 475 249 4,380 2020 2,902 408 124 3,434
Schedule of reconciliation of operating revenues and intercompany revenues	A reconciliation of operating revenues and intercompany revenues is shown in the following table. Third Party Gross Revenues Intercompany Revenues Total Gross Revenues Less Gross Gas Costs Operating Revenues (in millions) 2021 $ 3,881 $ 90 $ 3,971 $ 3,783 $ 188 2020 4,544 115 4,659 4,585 74

SUMMARY OF SIGNIFICANT ACCOUN_4

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - General (Narrative) (Details)	Dec. 31, 2022 state company
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of traditional electric operating companies | company	3
Traditional Electric Operating Companies
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Number of states in which entity provides utilities | state	3

SUMMARY OF SIGNIFICANT ACCOUN_5

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Costs for Affiliate Transactions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Alabama Power | Southern Company Services, Inc.
Related Party Transaction [Line Items]
Costs for services	$ 549	$ 504	$ 478
Alabama Power | Southern Natural Gas Company, LLC
Related Party Transaction [Line Items]
Costs for services	18	14	15
Georgia Power | Southern Company Services, Inc.
Related Party Transaction [Line Items]
Costs for services	762	663	639
Georgia Power | Southern Natural Gas Company, LLC
Related Party Transaction [Line Items]
Costs for services	99	108	108
Mississippi Power | Southern Company Services, Inc.
Related Party Transaction [Line Items]
Costs for services	115	120	149
Mississippi Power | Alabama Power | Power Pool
Related Party Transaction [Line Items]
Costs for services	4	9	4
Southern Power | Southern Company Services, Inc.
Related Party Transaction [Line Items]
Costs for services	86	89	87
Southern Power | Alabama Power | Power Pool
Related Party Transaction [Line Items]
Costs for services	29	15	8
Southern Power | Southern Natural Gas Company, LLC
Related Party Transaction [Line Items]
Costs for services	37	31	29
Southern Company Gas | Southern Company Services, Inc.
Related Party Transaction [Line Items]
Costs for services	262	239	237
Southern Company Gas | Southern Natural Gas Company, LLC
Related Party Transaction [Line Items]
Costs for services	$ 27	$ 29	$ 29

SUMMARY OF SIGNIFICANT ACCOUN_6

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Affiliate Transactions (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Southern Nuclear Operating Company, Inc. | Alabama Power
Related Party Transaction [Line Items]
Costs for services	$ 267	$ 258	$ 262
Southern Nuclear Operating Company, Inc. | Georgia Power
Related Party Transaction [Line Items]
Costs for services	895	906	883
Southern Power | Georgia Power
Related Party Transaction [Line Items]
Costs for services	151	132	141
Southern Natural Gas Company, LLC | Alabama Power
Related Party Transaction [Line Items]
Costs for services	18	14	15
Southern Natural Gas Company, LLC | Georgia Power
Related Party Transaction [Line Items]
Costs for services	99	108	108
Southern Natural Gas Company, LLC | Southern Power
Related Party Transaction [Line Items]
Costs for services	37	31	29
Southern Natural Gas Company, LLC | Southern Company Gas
Related Party Transaction [Line Items]
Costs for services	27	29	29
Southern Company Gas | Southern Power
Related Party Transaction [Line Items]
Costs for services	0	18	26
Southern Company Services, Inc. | Alabama Power
Related Party Transaction [Line Items]
Costs for services	549	504	478
Southern Company Services, Inc. | Georgia Power
Related Party Transaction [Line Items]
Costs for services	762	663	639
Southern Company Services, Inc. | Southern Power
Related Party Transaction [Line Items]
Costs for services	86	89	87
Southern Company Services, Inc. | Southern Company Gas
Related Party Transaction [Line Items]
Costs for services	262	239	237
PowerSecure | Southern Company Gas | US General Services Administration
Related Party Transaction [Line Items]
Costs for services	10
Contract amount	70
Non-Fuel Expense | Mississippi Power | Alabama Power
Related Party Transaction [Line Items]
Costs for services	6	10	9
Purchased Power from Affiliates | Southern Power
Related Party Transaction [Line Items]
Costs for services	154	139	139
Operating Lease PPA | Southern Power
Related Party Transaction [Line Items]
Costs for services	116	112	115
Electric Transmission | Southern Company Services, Inc. | Southern Power
Related Party Transaction [Line Items]
Costs for services	$ 39	$ 28	$ 15

SUMMARY OF SIGNIFICANT ACCOUN_7

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Revenues (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 29,279	$ 23,113	$ 20,375
Southern Company Gas
Disaggregation of Revenue [Line Items]
Period for collection of revenue prior to billings	24 months
Total operating revenues	$ 5,962	4,380	3,434
Southern Company Gas | Alternative revenue programs
Disaggregation of Revenue [Line Items]
Total operating revenues	$ (5)	$ 11	$ 3

SUMMARY OF SIGNIFICANT ACCOUN_8

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration of Credit Risk (Narrative) (Details) - Atlanta Gas Light	Dec. 31, 2022 customer
Concentration Risk [Line Items]
Number of customers in Georgia	14
Percent of highest month's estimated bill	200%

SUMMARY OF SIGNIFICANT ACCOUN_9

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Concentration of Revenue (Narrative) (Details)	12 Months Ended
	Dec. 31, 2022
Mississippi Power
Concentration Risk [Line Items]
Wholesale customers representing total operating revenues	12.40%

SUMMARY OF SIGNIFICANT ACCOU_10

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Income and Other Taxes (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Southern Power
Tax Credit Carryforward [Line Items]
Percentage reduction in tax basis of assets	50%
Southern Company Gas
Tax Credit Carryforward [Line Items]
Excise taxes collected	$ 162	$ 122	$ 107
Included In Operating Expenses | Southern Company Gas
Tax Credit Carryforward [Line Items]
Excise taxes collected	$ 158	$ 119	$ 104

SUMMARY OF SIGNIFICANT ACCOU_11

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Total AFUDC and Interest Capitalized (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Capitalized Contract Cost [Line Items]
Total AFUDC and interest capitalized	$ 327	$ 282	$ 230
Alabama Power
Capitalized Contract Cost [Line Items]
Total AFUDC and interest capitalized	90	68	61
Georgia Power
Capitalized Contract Cost [Line Items]
Total AFUDC and interest capitalized	213	190	138
Mississippi Power
Capitalized Contract Cost [Line Items]
Total AFUDC and interest capitalized	0	0	1
Southern Power
Capitalized Contract Cost [Line Items]
Total AFUDC and interest capitalized	0	6	11
Southern Company Gas
Capitalized Contract Cost [Line Items]
Total AFUDC and interest capitalized	$ 24	$ 18	$ 18

SUMMARY OF SIGNIFICANT ACCOU_12

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Average AFUDC Composite Rates (Details)	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Alabama Power
Capitalized Contract Cost [Line Items]
Composite rate	7.90%	7.90%	8.10%
Georgia Power
Capitalized Contract Cost [Line Items]
Composite rate	7.30%	7.20%	6.90%
Mississippi Power
Capitalized Contract Cost [Line Items]
Composite rate	5.30%	2.50%	5.40%
Atlanta Gas Light
Capitalized Contract Cost [Line Items]
Composite rate	7.60%	7.70%	7.70%
Chattanooga Gas
Capitalized Contract Cost [Line Items]
Composite rate	7.10%	7.10%	7.10%
Nicor Gas
Capitalized Contract Cost [Line Items]
Composite rate	2%	0.10%	0.70%

SUMMARY OF SIGNIFICANT ACCOU_13

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Goodwill and Other Intangible Assets and Liabilities (Narrative) (Details) - USD ($)	3 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Goodwill impairment	$ 119,000,000
Goodwill	5,161,000,000	$ 5,280,000,000	$ 5,280,000,000
Intangible liabilities included in other deferred credits and liabilities	1,167,000,000	816,000,000
PowerSecure
Finite-Lived Intangible Assets [Line Items]
Goodwill	144,000,000
Southern Company Gas
Finite-Lived Intangible Assets [Line Items]
Goodwill	5,015,000,000	5,015,000,000
Intangible liabilities included in other deferred credits and liabilities	$ 179,000,000	$ 77,000,000

SUMMARY OF SIGNIFICANT ACCOU_14

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Goodwill Balances (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Goodwill [Line Items]
Goodwill	$ 5,161	$ 5,280	$ 5,280
Southern Company Gas
Goodwill [Line Items]
Goodwill	5,015	5,015
Gas distribution operations | Southern Company Gas
Goodwill [Line Items]
Goodwill	4,034	4,034
Gas marketing services | Southern Company Gas
Goodwill [Line Items]
Goodwill	$ 981	$ 981

SUMMARY OF SIGNIFICANT ACCOU_15

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Other Intangible Assets (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 671	$ 677
Accumulated Amortization	(340)	(307)
Other Intangible Assets, Net	331	370
Intangible assets, gross	746	752
Intangible assets, net	406	445
FCC licenses
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	75	75
Accumulated Amortization	0	0
Other Intangible Assets, Net	75	75
Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	212	212
Accumulated Amortization	(162)	(150)
Other Intangible Assets, Net	50	62
Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	64	64
Accumulated Amortization	(44)	(38)
Other Intangible Assets, Net	20	26
PPA fair value adjustments
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	390	390
Accumulated Amortization	(129)	(109)
Other Intangible Assets, Net	261	281
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	5	11
Accumulated Amortization	(5)	(10)
Other Intangible Assets, Net	0	1
Southern Power
Finite-Lived Intangible Assets [Line Items]
Accumulated Amortization	(129)	(109)
Southern Power | PPA fair value adjustments
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	390	390
Accumulated Amortization	(129)	(109)
Other Intangible Assets, Net	261	281
Southern Company Gas
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	182	182
Accumulated Amortization	(156)	(145)
Other Intangible Assets, Net	26	37
Intangible assets, net	26	37
Southern Company Gas | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	156	156
Accumulated Amortization	(139)	(130)
Other Intangible Assets, Net	17	26
Southern Company Gas | Trade names
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	26	26
Accumulated Amortization	(17)	(15)
Other Intangible Assets, Net	$ 9	$ 11

SUMMARY OF SIGNIFICANT ACCOU_16

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Amortization of Other Intangible Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Finite-Lived Intangible Assets [Line Items]
Amortization associated with other intangible assets	$ 39	$ 44	$ 49
Estimated future amortization
2023	36
2024	35
2025	31
2026	26
2027	23
Southern Power
Finite-Lived Intangible Assets [Line Items]
Amortization associated with other intangible assets	20	20	20
Estimated future amortization
2023	20
2024	20
2025	20
2026	20
2027	20
Southern Company Gas
Finite-Lived Intangible Assets [Line Items]
Amortization associated with other intangible assets	11	15	19
Estimated future amortization
2023	9
2024	8
2025	6
2026	3
2027	0
Southern Company Gas | Gas marketing services
Finite-Lived Intangible Assets [Line Items]
Amortization associated with other intangible assets	11	15	17
Southern Company Gas | Wholesale gas services
Finite-Lived Intangible Assets [Line Items]
Amortization associated with other intangible assets	0	0	2
Operating Revenues
Finite-Lived Intangible Assets [Line Items]
Amortization associated with other intangible assets	$ 20	$ 20	$ 22

SUMMARY OF SIGNIFICANT ACCOU_17

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Transmission Receivables/Prepayments (Narrative) (Details)	12 Months Ended
	Dec. 31, 2022
Southern Power
Revenue Recognition, Multiple-deliverable Arrangements [Line Items]
Period of reimbursement for transmission costs	5 years

SUMMARY OF SIGNIFICANT ACCOU_18

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 1,917	$ 1,798
Restricted cash:
Total cash, cash equivalents, and restricted cash	2,037	1,829	$ 1,068	$ 1,978
Other current assets
Restricted cash:
Restricted cash	62	2
Other Noncurrent Assets
Restricted cash:
Restricted cash	58	29
Southern Power
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	131	107
Restricted cash:
Total cash, cash equivalents, and restricted cash	133	135	182	279
Southern Power | Other current assets
Restricted cash:
Restricted cash	0	0
Southern Power | Other Noncurrent Assets
Restricted cash:
Restricted cash	3	29
Southern Power | Estimated Construction Completion Costs | Deuel Harvest
Restricted cash:
Restricted cash	3	10
Southern Power | Tax Equity Contributions | Garland
Restricted cash:
Restricted cash		19
Southern Company Gas
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	81	45
Restricted cash:
Total cash, cash equivalents, and restricted cash	83	48	19	49
Southern Company Gas | Other current assets
Restricted cash:
Restricted cash	2	2
Southern Company Gas | Other Noncurrent Assets
Restricted cash:
Restricted cash	0	0
Georgia Power
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	364	33
Restricted cash:
Total cash, cash equivalents, and restricted cash	480	$ 33	$ 9	$ 52
Georgia Power | Other current assets
Restricted cash:
Restricted cash	60
Georgia Power | Other Noncurrent Assets
Restricted cash:
Restricted cash	$ 56

SUMMARY OF SIGNIFICANT ACCOU_19

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Storm Damage and Reliability Reserves (Details) - USD ($) $ in Millions	12 Months Ended			36 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2022
Liability for Catastrophe Claims [Line Items]
Reliability reserve, amount deferred	$ 191			$ 191
Alabama Power
Liability for Catastrophe Claims [Line Items]
Additional accruals authorized by state PSCs		$ 65	$ 100
Reliability reserve, amount deferred	166			166
Alabama Power | Storm damage reserves
Liability for Catastrophe Claims [Line Items]
Charges against storm damage reserves	24			24
Georgia Power
Liability for Catastrophe Claims [Line Items]
Storm damage reserves				213
Georgia Power | Storm damage reserves
Liability for Catastrophe Claims [Line Items]
Charges against storm damage reserves	82			82
Mississippi Power
Liability for Catastrophe Claims [Line Items]
Reliability reserve, amount deferred	25			25
Mississippi Power | Storm damage reserves
Liability for Catastrophe Claims [Line Items]
Charges against storm damage reserves	0			$ 0
Major storms
Liability for Catastrophe Claims [Line Items]
Storm damage reserves	239	286	326
Major storms | Alabama Power
Liability for Catastrophe Claims [Line Items]
Additional accruals authorized by state PSCs		65	100
Storm damage reserves	19	75	112
Major storms | Georgia Power
Liability for Catastrophe Claims [Line Items]
Storm damage reserves	213	213	213
Major storms | Mississippi Power
Liability for Catastrophe Claims [Line Items]
Storm damage reserves	$ 6.9	$ (1.8)	$ 0.8

SUMMARY OF SIGNIFICANT ACCOU_20

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Natural Gas for Sale (Narrative) (Details) - Nicor Gas $ in Millions	Dec. 31, 2022 USD ($)
Inventory [Line Items]
LIFO inventory balance	$ 170
Estimated replacement cost of inventory	$ 613

SUMMARY OF SIGNIFICANT ACCOU_21

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Provision for Uncollectible Accounts (Narrative) (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Accounting Policies [Abstract]
Uncollectible accounts, average percent of revenues (less than)	1%	1%	1%

SUMMARY OF SIGNIFICANT ACCOU_22

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Financial Instruments (Narrative) (Details)	Dec. 31, 2022 USD ($)
Alabama Power
Derivative [Line Items]
Derivative collateral obligation to return cash	$ 0

SUMMARY OF SIGNIFICANT ACCOU_23

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Schedule of AOCI (Loss) Balances, Net of Tax Effects (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 32,276	$ 32,234	$ 31,759
Current period change	71	158	(75)
Ending balance	34,532	32,276	32,234
Qualifying Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(162)
Current period change	13
Ending balance	(149)	(162)
Pension and Other Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(76)
Current period change	58
Ending balance	(18)	(76)
Accumulated Other Comprehensive Income (Loss)(*)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(237)	(395)	(321)
Current period change	71
Ending balance	(167)	(237)	(395)
Southern Power
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	6,598	6,631	6,622
Current period change	10	40	(42)
Ending balance	6,916	6,598	6,631
Southern Power | Qualifying Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	1
Current period change	(10)
Ending balance	(9)	1
Southern Power | Pension and Other Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(29)
Current period change	20
Ending balance	(9)	(29)
Southern Power | Accumulated Other Comprehensive Income (Loss)(*)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(27)	(67)	(26)
Current period change	10
Ending balance	(18)	(27)	(67)
Southern Company Gas
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	9,916	9,767	9,506
Current period change	7	46	(29)
Ending balance	10,397	9,916	9,767
Southern Company Gas | Qualifying Hedges
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(14)
Current period change	(11)
Ending balance	(25)	(14)
Southern Company Gas | Pension and Other Postretirement Benefit Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	38
Current period change	18
Ending balance	56	38
Southern Company Gas | Accumulated Other Comprehensive Income (Loss)(*)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	24	(22)	7
Current period change	7
Ending balance	$ 31	$ 24	$ (22)

REGULATORY MATTERS - Schedule o

REGULATORY MATTERS - Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions			12 Months Ended				36 Months Ended
	Jan. 01, 2023	Dec. 06, 2022	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2022
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 5,833	$ 4,711		$ 5,833
Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				2,340	1,217		2,340
Customer refund		$ 318
Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				4,663	3,928		4,663
Costs recovered annually				12	12	$ 12
Storm damage reserves							213
Georgia Power | Scenario, Forecast
Schedule of Regulatory Assets and Liabilities [Line Items]
Costs recovered annually			$ 5
Storm damage reserves	$ 31
Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				4	46		4
Regulatory asset amortization period						4 years
Regulatory liability amortization period						3 years
Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(1,891)	(1,471)		(1,891)
Deferred Income Tax Credits
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(5,251)	(5,636)		(5,251)
Deferred Income Tax Credits | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(1,925)	(1,968)		(1,925)
Deferred Income Tax Credits | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(2,244)	(2,537)		(2,244)
Deferred Income Tax Credits | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(269)	(288)		(269)
Regulatory liabilities				$ 33			33
Deferred Income Tax Credits | Mississippi Power | Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liability amortization period				3 years
Deferred Income Tax Credits | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (788)	(816)		(788)
Other Cost of Removal Obligations
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(1,430)	(1,826)		(1,430)
Other Cost of Removal Obligations | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				11	(192)		11
Other Cost of Removal Obligations | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				462	278		462
Other Cost of Removal Obligations | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(196)	(195)		(196)
Other Cost of Removal Obligations | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(1,707)	(1,683)		(1,707)
Storm/Property Damage Reserves
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(216)	(133)		(216)
Storm/Property Damage Reserves | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(97)	(103)		(97)
Storm/Property Damage Reserves | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(83)	0		(83)
Storm/Property Damage Reserves | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(36)	(30)		(36)
Storm/Property Damage Reserves | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Fuel Hedging (Realized And Unrealized) gains
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(83)			(83)
Fuel Hedging (Realized And Unrealized) gains | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(38)			(38)
Fuel Hedging (Realized And Unrealized) gains | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(21)			(21)
Fuel Hedging (Realized And Unrealized) gains | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(24)			(24)
Fuel Hedging (Realized And Unrealized) gains | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0			0
Reliability reserves
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(191)			(191)
Reliability reserves | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(166)			(166)
Reliability reserves | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0			0
Reliability reserves | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(25)			(25)
Reliability reserves | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0			0
Customer Refunds
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(183)	(189)		(183)
Customer Refunds | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(62)	(181)		(62)
Regulatory liabilities				62	181		62
Customer Refunds | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(121)	(8)		(121)
Regulatory liabilities				119	5		119
Customer Refunds | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Customer Refunds | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Over Recovered Regulatory Clause Revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(64)	(63)		(64)
Over Recovered Regulatory Clause Revenues | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	(1)		0
Over Recovered Regulatory Clause Revenues | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				(38)	(59)		(38)
Over Recovered Regulatory Clause Revenues | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Over Recovered Regulatory Clause Revenues | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (26)	(3)		(26)
Regulatory liability amortization period				5 years
Other Regulatory Liabilities
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (239)	(121)		(239)
Other Regulatory Liabilities | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (40)	(29)		(40)
Regulatory liability amortization period				11 years
Other Regulatory Liabilities | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (21)	(24)		(21)
Regulatory liability amortization period				10 years
Other Regulatory Liabilities | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (3)	(4)		(3)
Regulatory liability amortization period				4 years
Other Regulatory Liabilities | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ (93)	(57)		(93)
Regulatory liability amortization period				20 years
Fuel Hedging (Realized And Unrealized) losses | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liability amortization period				3 years 6 months
Fuel Hedging (Realized And Unrealized) losses | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liability amortization period				3 years
Fuel Hedging (Realized And Unrealized) losses | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory liability amortization period				4 years
Excess Deferred Income Tax Liabilities Not Subject to Normalization | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 1			1
AROs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				6,096	5,685		6,096
AROs | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 1,971	1,576		1,971
AROs | Alabama Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				53 years
AROs | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 3,829	3,866		3,829
AROs | Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				57 years
AROs | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 242	236		242
AROs | Mississippi Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				55 years
AROs | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 0	0		0
AROs | Southern Company Gas | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				80 years
Retiree Benefit Plans
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 2,517	2,998		2,517
Retiree Benefit Plans | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 675	747		675
Retiree Benefit Plans | Alabama Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				13 years
Retiree Benefit Plans | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 848	962		848
Retiree Benefit Plans | Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				13 years
Retiree Benefit Plans | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 113	145		113
Retiree Benefit Plans | Mississippi Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				13 years
Retiree Benefit Plans | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 114	95		114
Retiree Benefit Plans | Southern Company Gas | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				14 years
Remaining Net Book Value of Retired Assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 1,543	1,050		1,543
Remaining Net Book Value of Retired Assets | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				562	574		562
Remaining Net Book Value of Retired Assets | Alabama Power | Plant Gorgas Units 8, 9, And 10
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 492			492
Remaining Net Book Value of Retired Assets | Alabama Power | Maximum | Plant Gorgas Units 8, 9, And 10
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				15 years
Remaining Net Book Value of Retired Assets | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 962	$ 455		962
Remaining Net Book Value of Retired Assets | Georgia Power | Plant Wansley Units 1 and 2
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 562			562
Regulatory asset amortization period				8 years
Remaining Net Book Value of Retired Assets | Georgia Power | Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 396			396
Remaining Net Book Value of Retired Assets | Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				3 years	4 years
Remaining Net Book Value of Retired Assets | Georgia Power | Maximum | Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				13 years
Remaining Net Book Value of Retired Assets | Georgia Power | Minimum | Plant Hammond Units 1 - 4 and Plant Branch Units 2 - 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				1 year
Remaining Net Book Value of Retired Assets | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 19	$ 21		19
Remaining Net Book Value of Retired Assets | Mississippi Power | Plant Watson and Plant Greene County | Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				10 years
Remaining Net Book Value of Retired Assets | Mississippi Power | Plant Watson and Plant Greene County | Wholesale electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				14 years
Remaining Net Book Value of Retired Assets | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 0	0		0
Under Recovered Regulatory Clause Revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				953	806		953
Under Recovered Regulatory Clause Revenues | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 788	225		788
Under Recovered Regulatory Clause Revenues | Alabama Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				8 years
Under Recovered Regulatory Clause Revenues | Alabama Power | Minimum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				2 years
Under Recovered Regulatory Clause Revenues | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 0	0		0
Regulatory asset amortization period				2 years
Under Recovered Regulatory Clause Revenues | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 31	49		31
Under Recovered Regulatory Clause Revenues | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 134	532		134
Regulatory asset amortization period				5 years
Deferred Income Tax Charges
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 866	829		866
Deferred Income Tax Charges | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				250	240		250
Deferred Income Tax Charges | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				583	555		583
Deferred Income Tax Charges | Georgia Power | Plant Vogtle Units 3 and 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset				145			145
Deferred Income Tax Charges | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				30	31		30
Deferred Income Tax Charges | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Environmental Remediation
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				294	302		294
Environmental Remediation | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Environmental Remediation | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				25	35		25
Environmental Remediation | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Environmental Remediation | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				269	267		269
Loss on Reacquired Debt
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				257	281		257
Loss on Reacquired Debt | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 38	42		38
Loss on Reacquired Debt | Alabama Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				25 years
Loss on Reacquired Debt | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 213	231		213
Loss on Reacquired Debt | Georgia Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				30 years
Loss on Reacquired Debt | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 5	6		5
Loss on Reacquired Debt | Mississippi Power | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				19 years
Loss on Reacquired Debt | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 1	2		1
Loss on Reacquired Debt | Southern Company Gas | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				5 years
Vacation Pay
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 212	207		212
Regulatory asset amortization period				1 year
Vacation Pay | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 82	81		82
Vacation Pay | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				108	102		108
Vacation Pay | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				10	10		10
Vacation Pay | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				12	14		12
Regulatory Clauses
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 142	142		142
Costs recovered annually, period of recovery				8 years
Regulatory Clauses | Scenario, Forecast
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period	5 years
Regulatory Clauses | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 142	142		142
Regulatory Clauses | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Regulatory Clauses | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Regulatory Clauses | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Software and Cloud Computing Costs
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 111	73		111
Regulatory asset amortization period				5 years
Software and Cloud Computing Costs | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 46	35		46
Regulatory asset amortization period				10 years
Software and Cloud Computing Costs | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 59	33		59
Software and Cloud Computing Costs | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Software and Cloud Computing Costs | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 6	5		6
Regulatory asset amortization period				10 years
Nuclear Outage
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 82	75		82
Nuclear Outage | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 52	41		52
Nuclear Outage | Alabama Power | Plant Farley
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				18 months
Nuclear Outage | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 30	34		30
Nuclear Outage | Georgia Power | Maximum | Plant Hatch (nuclear)
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				24 months
Nuclear Outage | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 0	0		0
Nuclear Outage | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Long Term Debt Fair Value Adjustment
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				69	79		69
Long Term Debt Fair Value Adjustment | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Long Term Debt Fair Value Adjustment | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Long Term Debt Fair Value Adjustment | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Long Term Debt Fair Value Adjustment | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 69	79		69
Long Term Debt Fair Value Adjustment | Southern Company Gas | Maximum
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				16 years
Fuel Hedging (Realized And Unrealized) losses
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 60	(176)		60
Fuel Hedging (Realized And Unrealized) losses | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				15	(50)		15
Fuel Hedging (Realized And Unrealized) losses | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				45	(72)		45
Fuel Hedging (Realized And Unrealized) losses | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	(54)		0
Fuel Hedging (Realized And Unrealized) losses | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Storm Damage
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				44	97		44
Storm Damage | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Storm Damage | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	48		0
Storm Damage | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				44	49		44
Storm Damage | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Plant Daniel Units 3 and 4
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				27	28		27
Plant Daniel Units 3 and 4 | Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				18			18
Plant Daniel Units 3 and 4 | Wholesale electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				9			9
Plant Daniel Units 3 and 4 | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Plant Daniel Units 3 and 4 | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Plant Daniel Units 3 and 4 | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				27	28		27
Plant Daniel Units 3 and 4 | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Kemper County energy facility assets, net
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				20	35		20
Kemper County energy facility assets, net | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Kemper County energy facility assets, net | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Kemper County energy facility assets, net | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				20	35		20
Regulatory asset				26			26
Regulatory liabilities				6			6
Kemper County energy facility assets, net | Mississippi Power | Retail electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset				17			17
Regulatory liabilities				6			6
Kemper County energy facility assets, net | Mississippi Power | Wholesale electric revenues
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset				10			10
Kemper County energy facility assets, net | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				0	0		0
Other Regulatory Assets
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				197	168		197
Other Regulatory Assets | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 36	38		36
Regulatory asset amortization period				21 years
Other Regulatory Assets | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 27	29		27
Regulatory asset amortization period				10 years
Other Regulatory Assets | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 16	7		16
Regulatory asset amortization period				14 years
Other Regulatory Assets | Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 118	$ 94		118
Regulatory asset amortization period				20 years
CCR AROs | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				38 years
CCR AROs | Georgia Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period				3 years
CCR AROs | Georgia Power | Scenario, Forecast
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset amortization period	4 years
Regulatory Clauses, Amortized Through PEP | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 12			12
Regulatory asset amortization period				3 years
Ad Valorem Tax Adjustment Clause | Mississippi Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Total regulatory assets (liabilities), net				$ 18			$ 18

REGULATORY MATTERS - APC Certif

REGULATORY MATTERS - APC Certificate of Convenience and Necessity and RGC (Details) $ in Millions		12 Months Ended
	Jul. 12, 2022 MW	Dec. 31, 2020 USD ($) MW	Dec. 31, 2022 USD ($) MW	Dec. 31, 2021 USD ($)	Dec. 31, 2019 MW
Schedule of Regulatory Assets and Liabilities [Line Items]
Construction work in progress			$ 10,896	$ 8,771
Plant in service, net of depreciation			82,232	81,513
Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Approved additional generating capacity, demand-side management and distributed energy resource programs | MW		200
Additional generating capacity, petitioned megawatts, total | MW					2,400
Construction work in progress			1,526	1,147
Plant in service, net of depreciation			$ 23,002	$ 22,822
Renewable generation certificate, authorized generating capacity (in MWs) | MW			500
Renewable generation certificate, generating capacity (in MWs) | MW			330
Alabama Power | Calhoun Power Company, LLC
Schedule of Regulatory Assets and Liabilities [Line Items]
Approximate nameplate capacity (in MWs) | MW	743
Alabama Power | Year 2020
Schedule of Regulatory Assets and Liabilities [Line Items]
PPA, additional generating capacity (in MWs) | MW		240
Plant Barry Unit 8 | Alabama Power
Schedule of Regulatory Assets and Liabilities [Line Items]
Approximate nameplate capacity (in MWs) | MW		720
Costs incurred, percentage of estimated in-service cost		5%
Estimated in-service cost		$ 652
Construction work in progress			$ 518
Construction in progress, work in progress amount			513
Plant in service, net of depreciation			$ 5

REGULATORY MATTERS - APC Rate R

REGULATORY MATTERS - APC Rate RSE (Details) - Alabama Power - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Jan. 31, 2021
Public Utilities, General Disclosures [Line Items]
Rate adjustment period		2 years
Maximum percentage of rate RSE		4%
Maximum annual percentage of ratio rate		5%
Adjusting point of weighted cost of equity		5.98%
Percent of basis points		0.07%
Authorized ROE		52.20%	51.60%
Customer refundable fees, refund payments, tranche one, percentage		25%
Customer refundable fees, refund payments, tranche two, percentage		40%
Customer refundable fees, refund payments, tranche two, percentage		75%
Customer refundable fees, refund payments, tranche one, review year with rate RSE upward adjustment, percentage		50%
Contract with customer, liability, bill credits			$ 55
Rate RSE increase						4.09%
Rate RSE increase amount						$ 228
Rate RSE refund liability		$ 62	181	$ 50
Rate RSE refund liability, portion attributable to reduce under recovered balance			$ 126
Minimum
Public Utilities, General Disclosures [Line Items]
Public utilities, actual weighted common equity return, threshold, percentage		6.15%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche one		6.15%	6.15%	6.15%	6.15%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche two		6.65%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche three		7.15%
Public utilities, actual weighted common equity return, threshold, review year with rate RSE upward adjustment, percentage		6.15%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, review year with rate RSE upward adjustment, percentage, tranche one		6.15%
Maximum
Public Utilities, General Disclosures [Line Items]
Public utilities, actual weighted common equity return, threshold, percentage		7.65%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche one		6.65%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche two		7.15%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, percentage, tranche three		7.65%
Customer refundable fees, refund payments, percentage		7.65%
Public utilities, actual weighted common equity return, threshold for customer refundable fees, refund payments, review year with rate RSE upward adjustment, percentage, tranche one		6.90%
Customer refundable fees, refund payments, review year with rate RSE upward adjustment, percentage		6.90%
Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Authorized ROE	55%

REGULATORY MATTERS - APC Rate C

REGULATORY MATTERS - APC Rate CNP New Plant (Details) - Alabama Power $ in Millions	Oct. 03, 2022 USD ($)
Public Utilities, General Disclosures [Line Items]
Increase to annual revenue requirement	$ 34
Increase to annual revenue requirement, percentage	0.60%

REGULATORY MATTERS - APC Rate_2

REGULATORY MATTERS - APC Rate CNP (Details) - Alabama Power - USD ($) $ in Millions		12 Months Ended
	Dec. 06, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Regulatory Assets and Liabilities [Line Items]
Under recovered certified power purchase agreements		$ 120	$ 84
Retail revenue requirement for environmental compliance		$ 255	59	$ 59
Retail revenue requirement for environmental compliance, as a percentage		3.70%
Over (under) recovered environmental clause		$ (47)	$ 16
Public utilities, approved rate increase (decrease), amount	$ 318
Approved rate increase, percent	4.60%
Other regulatory assets, current
Schedule of Regulatory Assets and Liabilities [Line Items]
Under recovered certified power purchase agreements		18
Other regulatory assets, deferred
Schedule of Regulatory Assets and Liabilities [Line Items]
Under recovered certified power purchase agreements		$ 102

REGULATORY MATTERS - APC Rate E

REGULATORY MATTERS - APC Rate ECR (Details) - Alabama Power $ in Millions	1 Months Ended					12 Months Ended
	Jan. 31, 2023 $ / KWH_Kilowatt_hour	Dec. 31, 2022 USD ($) $ / KWH_Kilowatt_hour	Nov. 30, 2022 $ / KWH_Kilowatt_hour	Aug. 31, 2022 USD ($) $ / KWH_Kilowatt_hour	Jul. 31, 2022 $ / KWH_Kilowatt_hour	Dec. 31, 2022 USD ($) $ / KWH_Kilowatt_hour	Dec. 31, 2020 USD ($) $ / KWH_Kilowatt_hour	Dec. 31, 2019 $ / KWH_Kilowatt_hour	Dec. 31, 2021 USD ($)
Schedule of Regulatory Assets and Liabilities [Line Items]
Current billing rates under rate ECR (usd per KWH) | $ / KWH_Kilowatt_hour		3.510	2.557	2.557	1.960	0.05910	1.960	0.02160
Reduction of over-collected fuel balance							$ 94
Current billing rates under rate ECR, percentage decrease							1.84%
Current billing rates under rate ECR, decrease, amount							$ 103
Current billing rates under rate ECR, amount		$ 500		$ 310
Over (under) recovered fuel cost		(622)				$ (622)			$ 126
Rate RSE refund liability, portion attributable to reduce under recovered balance									$ 126
Other regulatory assets, current
Schedule of Regulatory Assets and Liabilities [Line Items]
Over (under) recovered fuel cost		(102)				(102)
Other regulatory assets, deferred
Schedule of Regulatory Assets and Liabilities [Line Items]
Over (under) recovered fuel cost		$ (520)				$ (520)
Scenario, Forecast
Schedule of Regulatory Assets and Liabilities [Line Items]
Current billing rates under rate ECR (usd per KWH) | $ / KWH_Kilowatt_hour	0.05910

REGULATORY MATTERS - APC Accoun

REGULATORY MATTERS - APC Accounting Orders and Plant Greene County (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021	Sep. 30, 2021
Public Utilities, General Disclosures [Line Items]
Other deferred charges and assets	$ 20,148	$ 17,259
Alabama Power
Public Utilities, General Disclosures [Line Items]
Other deferred charges and assets	$ 5,372	4,549
Percent ownership	14%
Alabama Power | Software Accounting Order
Public Utilities, General Disclosures [Line Items]
Other deferred charges and assets	$ 46	35
Mississippi Power
Public Utilities, General Disclosures [Line Items]
Other deferred charges and assets	$ 828	$ 877
Mississippi Power | Plant Greene County Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Percent ownership			40%

REGULATORY MATTERS - APC Rate N

REGULATORY MATTERS - APC Rate NDR and Reliability Reserve Accounting Order (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 05, 2022	Sep. 30, 2022	Jul. 12, 2022
Public Utilities, General Disclosures [Line Items]
Plant in service, net of depreciation	$ 82,232,000,000	$ 81,513,000,000
Other utility plant, net	599,000,000	0
Other regulatory assets	860,000,000	653,000,000
Revision of Prior Period, Reclassification, Adjustment
Public Utilities, General Disclosures [Line Items]
Plant in service, net of depreciation				$ (42,000,000)	$ (600,000,000)
Other utility plant, net					$ 600,000,000
Other regulatory assets				$ 42,000,000
Alabama Power
Public Utilities, General Disclosures [Line Items]
Minimum natural disaster reserve balance, triggering establishment charge	50,000,000
Natural disaster reserve authorized limit	75,000,000					$ 35,000,000
Maximum rate NDR charge per month, monthly nonresidential customer account	5					10
Maximum rate NDR charge per month, monthly residential customer account	2.50					$ 5
Additional accruals authorized by state PSCs		65,000,000	$ 100,000,000
Annual recovery amount	14,000,000	6,000,000	$ 5,000,000
Regulatory asset, amortization period	97,000,000	103,000,000
NDR, expected recovery amount	12,000,000
Plant in service, net of depreciation	23,002,000,000	22,822,000,000
Other utility plant, net	599,000,000	0
Other regulatory assets	$ 474,000,000	$ 208,000,000
Alabama Power | Minimum
Public Utilities, General Disclosures [Line Items]
Maximum period for recovery deferred stock related operations and maintenance costs and any future reserve deficits	24 months
Alabama Power | Maximum
Public Utilities, General Disclosures [Line Items]
Maximum period for recovery deferred stock related operations and maintenance costs and any future reserve deficits	48 months

REGULATORY MATTERS - GPC Tariff

REGULATORY MATTERS - GPC Tariffs (Details) - Georgia Power - USD ($) $ in Millions	Dec. 20, 2022	Dec. 31, 2019
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount, due in next fiscal year	$ 216
Requested rate increase (decrease), amount, due in 2024	377	$ 111
Requested rate increase (decrease), amount, due in 2025	403	157
Traditional base
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount, due in next fiscal year	194
Requested rate increase (decrease), amount, due in 2024	275	120
Requested rate increase (decrease), amount, due in 2025	315	192
ECCR
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount, due in next fiscal year	(21)
Requested rate increase (decrease), amount, due in 2024	66	2
Requested rate increase (decrease), amount, due in 2025	81	(12)
DSM
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount, due in next fiscal year	37
Requested rate increase (decrease), amount, due in 2024	27	(15)
Requested rate increase (decrease), amount, due in 2025	(2)	(25)
MFF
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount, due in next fiscal year	6
Requested rate increase (decrease), amount, due in 2024	9	4
Requested rate increase (decrease), amount, due in 2025	$ 9	$ 2

REGULATORY MATTERS - GPC Rate P

REGULATORY MATTERS - GPC Rate Plans, Integrated Resource Plan and COVID-19 Costs (Details) $ in Millions

1 Months Ended

12 Months Ended

Jan. 01, 2024 MW

Aug. 31, 2022 MW

Aug. 26, 2022 USD ($)

Jul. 21, 2022 agreement MW

Jan. 01, 2022 USD ($)

Jan. 01, 2021 USD ($)

Nov. 30, 2021 USD ($)

Jun. 30, 2021 USD ($)

Dec. 31, 2028 MW

Dec. 31, 2026 MW

Dec. 31, 2025 USD ($) MW

Dec. 31, 2024 USD ($) MW

Dec. 31, 2023 USD ($)

Dec. 31, 2022 USD ($) ashPond MW

Dec. 31, 2021 USD ($) MW

Dec. 31, 2020 USD ($)

Dec. 31, 2019

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

$ 5,833

$ 4,711

Customer Refunds

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

$ (183)

$ (189)

Georgia Power

Public Utilities, General Disclosures [Line Items]

Approved rate decrease

$ 10

Approved rate increase

$ 90

Public utilities, approved rate increase (decrease), amount

$ 252

$ (44)

Requested additional generating capacity (in MW) | MW

2,300

970

Approved additional generating capacity (in MW) | MW

970

Number of ash ponds | ashPond

1

Net regulatory assets

$ 4,663

$ 3,928

Requested number of power purchase agreements to be certified | agreement

6

Requested number of affiliate power purchase agreements to be certified | agreement

5

Incremental COVID-19 costs deferred

$ 25

21

Georgia Power | ECCR

Public Utilities, General Disclosures [Line Items]

Regulatory asset amortization period

4 years

Approved rate decrease

$ 20

Georgia Power | 2022 Alternate Rate Plan

Public Utilities, General Disclosures [Line Items]

Retail rate of return on common equity

10.50%

Equity rate of return on common equity

56%

Portion of actual earnings above approved ROE band applied to reduce regulatory assets

40%

Portion of actual earnings above approved ROE band refunded to customers

40%

Portion of actual earnings above approved ROE band retained by subsidiary company

20%

Georgia Power | 2019 Alternate Rate Plan

Public Utilities, General Disclosures [Line Items]

Retail rate of return on common equity

10.50%

Portion of actual earnings above approved ROE band applied to reduce regulatory assets

40%

Portion of actual earnings above approved ROE band refunded to customers

40%

Portion of actual earnings above approved ROE band retained by subsidiary company

20%

Customer refund liability in absence of base rate case

$ 119

5

Georgia Power | Energy Storage

Public Utilities, General Disclosures [Line Items]

Requested additional generating capacity (in MW) | MW

500

Georgia Power | Biomass Generation

Public Utilities, General Disclosures [Line Items]

Requested additional generating capacity (in MW) | MW

140

Georgia Power | Scenario, Forecast

Public Utilities, General Disclosures [Line Items]

Incremental COVID-19 costs recovered, period

3 years

Georgia Power | Scenario, Forecast | ECCR

Public Utilities, General Disclosures [Line Items]

Compliance costs expected to be incurred

$ 510

$ 410

$ 320

Georgia Power | Scenario, Forecast | Subsequent Event

Public Utilities, General Disclosures [Line Items]

Requested additional generating capacity (in MW) | MW

1,567

228

265

380

88

Georgia Power | Plant Vogtle Unit 3

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

2,100

Requested rate increase (decrease), amount

3,600

Approved depreciation expense deferred, annual amount

$ 40

Requested rate increase, annual amount

$ 302

Georgia Power | Plant Wansley Unit 1

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

292

Georgia Power | Plant Wansley Unit 2

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

270

Net regulatory assets, unusable materials and supplies inventory

$ 13

Georgia Power | Plant Scherer Unit 3

Public Utilities, General Disclosures [Line Items]

Capacity of units included in request for decertification of units | MW

614

Request for decertification of units, percentage of ownership

75%

Net regulatory assets

$ 601

Georgia Power | Plant Gaston Units 1 through 4

Public Utilities, General Disclosures [Line Items]

Capacity of units included in request for decertification of units | MW

500

Request for decertification of units, percentage of ownership

50%

Georgia Power | Plant Bowen Units 1 and 2

Public Utilities, General Disclosures [Line Items]

Regulatory asset amortization period

4 years

Capacity of units included in request for decertification of units | MW

1,400

Georgia Power | Plant Tugalo

Public Utilities, General Disclosures [Line Items]

Planned expenses to modernize plant

$ 115

Georgia Power | Plant Wansley Units 1 and 2

Public Utilities, General Disclosures [Line Items]

Capacity of units included in request for decertification of units | MW

926

Request for decertification of units, percentage of ownership

53.50%

Georgia Power | Customer Refunds

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

$ (121)

(8)

Georgia Power | Customer Refunds | 2019 Alternate Rate Plan

Public Utilities, General Disclosures [Line Items]

Portion of actual earnings above approved ROE band refunded to customers, value

119

5

Remaining Net Book Value of Retired Assets

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

1,543

1,050

Remaining Net Book Value of Retired Assets | Georgia Power

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

$ 962

$ 455

Remaining Net Book Value of Retired Assets | Georgia Power | Plant Scherer Unit 3

Public Utilities, General Disclosures [Line Items]

Regulatory asset amortization period

6 years

Net regulatory assets

$ 43

Remaining Net Book Value of Retired Assets | Georgia Power | Plant Bowen Units 1 and 2

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

$ 40

Remaining Net Book Value of Retired Assets | Georgia Power | Plant Wansley Units 1 and 2

Public Utilities, General Disclosures [Line Items]

Regulatory asset amortization period

8 years

Net regulatory assets

$ 562

Maximum | Georgia Power | 2022 Alternate Rate Plan

Public Utilities, General Disclosures [Line Items]

Retail rate of return on common equity

11.90%

Maximum | Georgia Power | 2019 Alternate Rate Plan

Public Utilities, General Disclosures [Line Items]

Retail rate of return on common equity

12%

Maximum | Remaining Net Book Value of Retired Assets | Georgia Power

Public Utilities, General Disclosures [Line Items]

Regulatory asset amortization period

3 years

4 years

Minimum | Georgia Power | 2022 Alternate Rate Plan

Public Utilities, General Disclosures [Line Items]

Retail rate of return on common equity

9.50%

Minimum | Georgia Power | 2019 Alternate Rate Plan

Public Utilities, General Disclosures [Line Items]

Retail rate of return on common equity

9.50%

REGULATORY MATTERS - GPC Fuel C

REGULATORY MATTERS - GPC Fuel Cost and Storm Damage Recovery (Details) - USD ($) $ in Millions		1 Months Ended	6 Months Ended	12 Months Ended		36 Months Ended
	Jan. 01, 2023	Nov. 30, 2021	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2020	Dec. 31, 2022
Public Utilities, General Disclosures [Line Items]
Net regulatory assets			$ 4,711	$ 5,833		$ 5,833
Other regulatory assets			653	860		860
Other regulatory assets, deferred			5,577	5,918		5,918
Georgia Power
Public Utilities, General Disclosures [Line Items]
Approved decrease in annual billing based on fuel cost recovery rate					$ 740
Approved decrease in annual billing based on fuel cost recovery rate, term					2 years
Public utilities, approved rate increase (decrease), amount		$ 252			$ (44)
Approved rate increase, percent		15%
Adjustment to fuel cost recovery rate if under recovered fuel balance exceeds budget thereafter			200
Over (under) recovered fuel balance			(400)	$ (2,100)		(2,100)
Required period for options and hedges				36 months
Storm damage reserves						213
Net regulatory assets			3,928	$ 4,663		4,663
Other regulatory assets			289	324		324
Other regulatory assets, deferred			$ 1,964	2,522		2,522
Georgia Power | Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Storm damage reserves	$ 31
Georgia Power | Storm damage reserves
Public Utilities, General Disclosures [Line Items]
Regulatory liabilities				83		83
Net regulatory assets				$ 48		$ 48

REGULATORY MATTERS - GPC Nuclea

REGULATORY MATTERS - GPC Nuclear Construction (Details) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2012 utility MW
Public Utilities, General Disclosures [Line Items]
Estimated loss on Plant Vogtle Units 3 and 4					$ 183	$ 1,692	$ 325
Georgia Power
Public Utilities, General Disclosures [Line Items]
Number of construction units approved | utility								2
Electric generating capacity (in MWs) | MW								1,100
Estimated cost to complete, pre-tax charge to income	$ 148	$ 32	$ 36
Estimated cost to complete, pre-tax charge to income, net of tax	110	24	27
Estimated loss on Plant Vogtle Units 3 and 4					183	$ 1,692	$ 325
Pre-tax charge to income	53	(102)	16	$ 440	$ 407
After tax charge to income	$ 40	$ (76)	$ 12	$ 328
Plant Vogtle Units 3 and 4 | Georgia Power
Public Utilities, General Disclosures [Line Items]
Percent ownership	45.70%				45.70%
Estimated construction financing costs	$ 3,500				$ 3,500
Construction financing costs incurred to date	3,200				3,200
Estimated cost to complete, construction contingency estimate and additional costs	307				307
Estimated cost to complete, additional construction contingency estimate	125				125
Estimated cost to complete, additional construction monitoring costs	9				$ 9
Plant Vogtle Units 3 and 4 | Georgia Power | Minimum | COVID-19
Public Utilities, General Disclosures [Line Items]
Estimated months of productivity loss					3 months
Construction financing costs	160				$ 160
Plant Vogtle Units 3 and 4 | Georgia Power | Maximum | COVID-19
Public Utilities, General Disclosures [Line Items]
Estimated months of productivity loss					4 months
Construction financing costs	$ 200				$ 200
Plant Vogtle Units 3 and 4 | Georgia Power | Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Period of notice required in the event letters of credit are not renewed					30 days
Plant Vogtle Unit 3 | Georgia Power
Public Utilities, General Disclosures [Line Items]
Additional base capital costs per month (up to)					$ 15
Plant Watson Unit 4 | Georgia Power
Public Utilities, General Disclosures [Line Items]
Additional base capital costs per month (up to)					$ 35

REGULATORY MATTERS - GPC Schedu

REGULATORY MATTERS - GPC Schedule of Nuclear Construction Cost and Schedule (Details) - USD ($) $ in Millions	3 Months Ended				12 Months Ended
	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Commitments [Line Items]
Total AFUDC and interest capitalized					$ 327	$ 282	$ 230
Georgia Power
Commitments [Line Items]
Total AFUDC and interest capitalized					213	$ 190	$ 138
Pre-tax charge to income	$ 53	$ (102)	$ 16	$ 440	407
Georgia Power | Plant Vogtle Units 3 and 4
Commitments [Line Items]
Base project capital cost forecast	10,533				10,533
Construction contingency estimate	60				60
Preliminary estimated cost to complete	10,593				10,593
Net investment	(9,521)				(9,521)
Remaining estimate to complete	1,072				1,072
Estimated cost to complete, costs not shared with other owners	610				610
Estimated cost to complete, construction monitoring costs approved for recovery	33				33
Total AFUDC and interest capitalized					421
Total AFUDC and interest capitalized, accrual amount	$ 304				$ 304

REGULATORY MATTERS - GPC Joint

REGULATORY MATTERS - GPC Joint Ownership Agreements (Details) - USD ($) $ in Thousands			3 Months Ended				12 Months Ended
	Oct. 04, 2022	Sep. 29, 2022	Dec. 31, 2022	Sep. 30, 2022	Jun. 30, 2022	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2016	Jun. 18, 2022
Public Utilities, General Disclosures [Line Items]
Agreement with third party, amount of costs over projected forecast to be paid by company		20%
Georgia Power
Public Utilities, General Disclosures [Line Items]
Amortization period							5 years
Pre-tax charge to income			$ 53,000	$ (102,000)	$ 16,000	$ 440,000	$ 407,000
After tax charge to income			$ 40,000	$ (76,000)	$ 12,000	$ 328,000
Plant Vogtle Units 3 and 4 | Georgia Power
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs	$ 345,000							$ 3,300,000
Ownership interest percentage required for voting for continuing construction			90%				90%
Production tax credits, aggregate purchase price (up to)							$ 300,000
Preliminary estimated cost to complete			$ 10,593,000				$ 10,593,000
Remaining share of construction costs, agreement to pay, percentage							100%
Percentage of costs, disallowed for recovery							6%
Costs disallowed for recovery, period							6 months
Public utilities, extension project schedule, term							1 year
Estimated cost to complete, starting dollar amount			$ 18,380,000				$ 18,380,000
Percent ownership			45.70%				45.70%
Plant Vogtle Units 3 and 4 | Georgia Power | Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs							$ 100
Plant Vogtle Units 3 and 4 | Georgia Power | Vogtle Owners | Tender Provision Dispute
Public Utilities, General Disclosures [Line Items]
Estimated cost to complete, starting dollar amount									$ 17,100,000
Plant Vogtle Units 3 and 4 | Georgia Power | MEAG Power
Public Utilities, General Disclosures [Line Items]
Agreement with third party, expected cost		$ 92,000
Plant Vogtle Units 3 and 4 | Georgia Power | Category I
Public Utilities, General Disclosures [Line Items]
Preliminary estimated cost to complete			$ 8,400,000				8,400,000
Additional construction capital costs, threshold							800,000
Plant Vogtle Units 3 and 4 | Georgia Power | Category II
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs							$ 80,000
Percentage of construction costs responsible to pay							55.70%
Plant Vogtle Units 3 and 4 | Georgia Power | Category II | Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs responsible to pay							44.30%
Plant Vogtle Units 3 and 4 | Georgia Power | Category II | Minimum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold							$ 800,000
Plant Vogtle Units 3 and 4 | Georgia Power | Category II | Maximum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold							1,600,000
Plant Vogtle Units 3 and 4 | Georgia Power | Category III
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs							$ 100,000
Percentage of construction costs responsible to pay							65.70%
Plant Vogtle Units 3 and 4 | Georgia Power | Category III | Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs responsible to pay							34.30%
Plant Vogtle Units 3 and 4 | Georgia Power | Category III | Maximum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold							$ 2,100,000

REGULATORY MATTERS - GPC Regula

REGULATORY MATTERS - GPC Regulatory Matters (Details) - Plant Vogtle Units 3 and 4 - Georgia Power $ in Millions

6 Months Ended

12 Months Ended

Feb. 16, 2023 USD ($)

Dec. 20, 2022 USD ($)

Oct. 04, 2022 USD ($)

Jan. 01, 2021

Jan. 01, 2020

Jan. 11, 2018 USD ($)

Jan. 01, 2018

Jan. 01, 2016

Jun. 30, 2022 USD ($) report

Jun. 30, 2021 USD ($) report

Dec. 31, 2024 USD ($)

Dec. 31, 2023 USD ($)

Dec. 31, 2022 USD ($)

Dec. 31, 2021 USD ($)

Dec. 31, 2020 USD ($)

Dec. 31, 2016 USD ($)

Dec. 31, 2009 USD ($)

Jun. 30, 2018 USD ($)

Dec. 31, 2015

Public Utilities, General Disclosures [Line Items]

Estimated in-service capital cost

$ 4,418

Proceeds from recovery of financing costs

$ 2,900

Project capital cost forecast

$ 7,300

Requested decrease in NCCR tariff

$ (36)

Additional construction capital costs

$ 345

$ 3,300

Payments for contractor settlement agreement

300

Amendment to estimated in-service capital cost

$ 5,680

Retail rate of return on common equity

10.95%

Authorized ROE

5.30%

8.30%

10%

10%

Potential decrease each month, percentage

0.10%

Return on equity reduction, negative impact on earnings

$ 300

$ 270

$ 150

Increase to base capital cost forecast not seeking recovery

$ 700

Twenty Fifth Vogtle Construction Monitoring Report

Public Utilities, General Disclosures [Line Items]

Number of approved construction monitoring reports | report

25

Approval of construction capital costs

$ 7,900

Maximum guarantee

1,700

Customer refund

$ 188

Number of additional reports reviewed | report

2

Twenty Sixth Vogtle Construction Monitoring Report

Public Utilities, General Disclosures [Line Items]

Approval of construction capital costs

$ 1,100

Scenario, Forecast

Public Utilities, General Disclosures [Line Items]

Return on equity reduction, negative impact on earnings

$ 60

$ 270

Scenario, Forecast | Twenty Fifth Vogtle Construction Monitoring Report

Public Utilities, General Disclosures [Line Items]

Approval of construction capital costs

$ 461

REGULATORY MATTERS - MPC 2019 B

REGULATORY MATTERS - MPC 2019 Base Rate Case and Performance Evaluation Plan (Details) - Mississippi Power $ in Millions	1 Months Ended				12 Months Ended
	Jun. 30, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	May 31, 2021 USD ($)	Dec. 31, 2022 filing	Dec. 31, 2020 USD ($)
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount	$ 18	$ 9	$ 16	$ 28		$ (16.7)
Approved rate decrease, percent	(1.90%)		(1.80%)			1.85%
Base rate case filing, measurement input, average equity ratio						53%
Base rate case filing, measurement input, maximum equity ratio						55%
Base rate case filing, measurement input, return on investment						7.57%
Regulatory asset amortization period						4 years
Regulatory liability amortization period						3 years
Annual base rate adjustment, increase in depreciation						$ 10
Annual base rate adjustment, compensation costs excluded						$ 3.9
Performance evaluation plan, number of filings per calendar year | filing					2
Weighted Average | Measurement Input, Average Customer Price
Public Utilities, General Disclosures [Line Items]
Performance evaluation plan, measurement input					0.40
Weighted Average | Measurement Input, Service Reliability
Public Utilities, General Disclosures [Line Items]
Performance evaluation plan, measurement input					0.40
Weighted Average | Measurement Input, Customer Satisfaction
Public Utilities, General Disclosures [Line Items]
Performance evaluation plan, measurement input					0.20

REGULATORY MATTERS - MPC Integr

REGULATORY MATTERS - MPC Integrated Resource Plan (Details) $ in Millions	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Sep. 30, 2021 MW	Dec. 31, 2019 MW
Public Utilities, General Disclosures [Line Items]
Net regulatory assets | $	$ 5,833	$ 4,711
Mississippi Power
Public Utilities, General Disclosures [Line Items]
Required fossil-stream generation retirements (in MWs) | MW				950
Net regulatory assets | $	4	$ 46
Mississippi Power | Plant Watson Unit 4
Public Utilities, General Disclosures [Line Items]
Required fossil-stream generation retirements (in MWs) | MW			268
Mississippi Power | Plant Greene County Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Required fossil-stream generation retirements (in MWs) | MW			103
Percent ownership			40%
Mississippi Power | Plant Greene County Units 1 and 2 | Alabama Power
Public Utilities, General Disclosures [Line Items]
Percent ownership			40%
Mississippi Power | Plant Daniel
Public Utilities, General Disclosures [Line Items]
Required fossil-stream generation retirements (in MWs) | MW			502
Percent ownership			50%
Net regulatory assets | $	499
Estimated amount remaining at retirement | $	$ 397

REGULATORY MATTERS - MPC Enviro

REGULATORY MATTERS - MPC Environmental Compliance Overview Plan (Details) - Mississippi Power - USD ($) $ in Millions		1 Months Ended				12 Months Ended
	Apr. 05, 2022	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	May 31, 2021	Dec. 31, 2020
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount		$ 18	$ 9	$ 16	$ 28	$ (16.7)
Environmental Compliance Overview Plan
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount	$ (1)			$ (9)

REGULATORY MATTERS - MPC Fuel C

REGULATORY MATTERS - MPC Fuel Cost Recovery and Ad Valorem Tax Adjustment (Details) - Mississippi Power - USD ($) $ in Millions

1 Months Ended

12 Months Ended

Feb. 14, 2023

Jan. 10, 2023

Jun. 30, 2023

Jan. 31, 2023

Jul. 31, 2022

Jun. 30, 2022

Feb. 28, 2022

Jan. 31, 2022

Dec. 31, 2021

Jun. 30, 2021

May 31, 2021

Feb. 28, 2021

Jan. 31, 2021

Feb. 29, 2020

Dec. 31, 2020

Dec. 31, 2022

Apr. 30, 2020

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 18

$ 9

$ 16

$ 28

$ (16.7)

Approved rate increase, percent

1.90%

1.80%

(1.85%)

PSC retail increase

$ 10

Public utilities, valorem taxes previously recovered, amount

$ 19

Ad Valorem Tax Adjustment

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 5

Subsequent Event

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 12

Retail electric revenues

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 43

$ 2

$ (24)

Over recovered fuel cost

4

$ 1

Retail electric revenues | Subsequent Event

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 25

Retail electric revenues | Scenario, Forecast | Subsequent Event

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 25

MRA Revenue

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 11

$ (5)

Under recovered fuel cost

$ 1

$ 6

MRA Revenue | Subsequent Event

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 22

REGULATORY MATTERS - MPC System

REGULATORY MATTERS - MPC System Restoration Rider (Details) - USD ($)			1 Months Ended				12 Months Ended
	Feb. 14, 2023	Feb. 13, 2023	Jun. 30, 2022	Dec. 31, 2021	Jun. 30, 2021	May 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Public Utilities, General Disclosures [Line Items]
Reliability reserve, amount deferred							$ 191,000,000
Subsequent Event
Public Utilities, General Disclosures [Line Items]
Minimum annual accrual, amount		$ 8,000,000
Major storms
Public Utilities, General Disclosures [Line Items]
Storm damage reserves accrual							239,000,000	$ 286,000,000	$ 326,000,000
Mississippi Power
Public Utilities, General Disclosures [Line Items]
Threshold above which actual damages are charged to the reserve (individually exceed)							50,000
Public utilities, approved rate increase (decrease), amount			$ 18,000,000	$ 9,000,000	$ 16,000,000	$ 28,000,000			(16,700,000)
Target property damage reserve				75,000,000				75,000,000
Reliability reserve, amount deferred							25,000,000
Mississippi Power | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Public utilities, approved rate increase (decrease), amount	$ 12,000,000
Mississippi Power | Retail electric revenues
Public Utilities, General Disclosures [Line Items]
Property damage reserve				$ 31,000,000			37,000,000	31,000,000
Mississippi Power | Major storms
Public Utilities, General Disclosures [Line Items]
Storm damage reserves accrual							$ 6,900,000	$ (1,800,000)	$ 800,000

REGULATORY MATTERS - MPC Munici

REGULATORY MATTERS - MPC Municipal and Rural Associations Tariff (Details) - Mississippi Power $ in Millions	Jul. 15, 2022 USD ($)	Dec. 31, 2022 MW	Aug. 26, 2022	Dec. 31, 2021
Municipal and Rural Associations Tariff
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease), amount | $	$ 23
Cooperative Energy
Public Utilities, General Disclosures [Line Items]
Counterparty's option to decrease services, percentage				2.50%
Power being supplied to counterparty | MW		400
Counterparty's electricity requirement at MRA delivery points			100%

REGULATORY MATTERS - GAS Schedu

REGULATORY MATTERS - GAS Schedule of Utility Regulation and Rate Design (Details)		1 Months Ended		12 Months Ended
	Aug. 01, 2022	Nov. 30, 2021	Sep. 30, 2021	Dec. 31, 2022
Nicor Gas
Public Utilities, General Disclosures [Line Items]
Authorized ROE		9.75%		9.75%
Atlanta Gas Light
Public Utilities, General Disclosures [Line Items]
Authorized ROE				10.25%
Virginia Natural Gas
Public Utilities, General Disclosures [Line Items]
Authorized ROE	10.35%		9.50%	9.50%
Chattanooga Gas
Public Utilities, General Disclosures [Line Items]
Authorized ROE				9.80%

REGULATORY MATTERS - GAS Infras

REGULATORY MATTERS - GAS Infrastructure Replacement Programs and Capital Projects (Details) $ in Millions	1 Months Ended		12 Months Ended
	Nov. 30, 2021 USD ($)	Jun. 30, 2021 USD ($) mi	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2014	Dec. 31, 2019 USD ($)
Public Utilities, General Disclosures [Line Items]
Capital expenditures related to qualifying projects			$ 7,923	$ 7,586	$ 7,522
Southern Company Gas
Public Utilities, General Disclosures [Line Items]
Capital expenditures related to qualifying projects			1,533	1,421	1,471
Capital expenditures			587
Over (under) recovered fuel cost				473
Southern Company Gas | Natural Gas Cost Under Recovery
Public Utilities, General Disclosures [Line Items]
Over (under) recovered fuel cost			108	266
Southern Company Gas | Other regulatory assets, deferred
Public Utilities, General Disclosures [Line Items]
Over (under) recovered fuel cost				207
Southern Company Gas | Steps to Advance Virginia's Energy (SAVE)
Public Utilities, General Disclosures [Line Items]
Capital expenditures			69	51	49
Nicor Gas
Public Utilities, General Disclosures [Line Items]
Capital expenditures related to qualifying projects				$ 408	$ 389
Nicor Gas | Regulatory Infrastructure Program
Public Utilities, General Disclosures [Line Items]
Program duration period						9 years
Nicor Gas | Maximum
Public Utilities, General Disclosures [Line Items]
Infrastructure investment, annual customer rate increase						4%
Infrastructure investment, annual customer rate increase in any given year						5.50%
Virginia Natural Gas | Steps to Advance Virginia's Energy (SAVE)
Public Utilities, General Disclosures [Line Items]
Program duration period					6 years
Approved infrastructure replacement program, approved investment amount, current fiscal year							$ 365
Infrastructure replacement program, approved investment variance amount							5
Virginia Natural Gas | Steps to Advance Virginia's Energy (SAVE) | Year 2020
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year							50
Virginia Natural Gas | Steps to Advance Virginia's Energy (SAVE) | Year 2021
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year							60
Virginia Natural Gas | Steps to Advance Virginia's Energy (SAVE) | Year 2022
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year							70
Virginia Natural Gas | Steps to Advance Virginia's Energy (SAVE) | Year 2023
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year							70
Virginia Natural Gas | Steps to Advance Virginia's Energy (SAVE) | Year 2024
Public Utilities, General Disclosures [Line Items]
Approved infrastructure replacement program, approved investment amount, current fiscal year							$ 70
Atlanta Gas Light
Public Utilities, General Disclosures [Line Items]
Gain contingency, unrecorded amount			68
Annual proceeds from strategic economic development projects			15
Approved annual recovery of capital investment	$ 286
Atlanta Gas Light | True-Up Recovery, Unrecognized Equity
Public Utilities, General Disclosures [Line Items]
Gain contingency, unrecorded amount			35
Chattanooga Gas
Public Utilities, General Disclosures [Line Items]
Program duration period		7 years
Pipeline replacement program, length of distribution main | mi		73
Preliminary estimated cost to complete		$ 118
Operating Segments | Gas distribution operations | Southern Company Gas
Public Utilities, General Disclosures [Line Items]
Gross property additions			$ 1,500

REGULATORY MATTERS - GAS Sche_2

REGULATORY MATTERS - GAS Schedule of Infrastructure Replacement Programs and Capital Projects (Details) - Southern Company Gas $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) mi	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Public Utilities, General Disclosures [Line Items]
Expenditures in 2022	$ 587
Expenditures Since Project Inception	$ 3,439
Pipe Installed Since Project Inception (in miles) | mi	1,837
Scope of Program (in miles) | mi	2,622
Investing In Illinois
Public Utilities, General Disclosures [Line Items]
Expenditures in 2022	$ 437
Expenditures Since Project Inception	$ 2,945
Pipe Installed Since Project Inception (in miles) | mi	1,297
Scope of Program (in miles) | mi	1,854
Program Duration	9 years
Steps to Advance Virginia's Energy (SAVE)
Public Utilities, General Disclosures [Line Items]
Expenditures in 2022	$ 69	$ 51	$ 49
Expenditures Since Project Inception	$ 411
Pipe Installed Since Project Inception (in miles) | mi	525
Scope of Program (in miles) | mi	695
Program Duration	13 years
System Reinforcement Rider
Public Utilities, General Disclosures [Line Items]
Expenditures in 2022	$ 76
Expenditures Since Project Inception	$ 76
Pipe Installed Since Project Inception (in miles) | mi	10
Program Duration	3 years
Pipeline Replacement Program
Public Utilities, General Disclosures [Line Items]
Expenditures in 2022	$ 5
Expenditures Since Project Inception	$ 7
Pipe Installed Since Project Inception (in miles) | mi	5
Scope of Program (in miles) | mi	73
Program Duration	7 years

REGULATORY MATTERS - GAS Rate P

REGULATORY MATTERS - GAS Rate Proceedings and Deferral of Incremental COVID-19 Costs (Details) $ in Millions

1 Months Ended

12 Months Ended

Jan. 03, 2023 USD ($) rider

Dec. 20, 2022 USD ($)

Aug. 01, 2022 USD ($)

Jan. 01, 2022 USD ($)

Nov. 01, 2020 USD ($)

Nov. 30, 2021 USD ($)

Sep. 30, 2021 USD ($)

Apr. 30, 2021 USD ($)

Feb. 28, 2021

Dec. 31, 2023 USD ($)

Dec. 31, 2022 USD ($)

Dec. 31, 2020 USD ($)

Dec. 31, 2021 USD ($)

Public Utilities, General Disclosures [Line Items]

Net regulatory assets

$ 5,833

$ 4,711

Nicor Gas

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 240

Authorized ROE

9.75%

9.75%

Public utilities, approved equity capital structure, percentage

54.50%

Nicor Gas | Subsequent Event

Public Utilities, General Disclosures [Line Items]

Authorized ROE

10.35%

Public utilities, approved equity capital structure, percentage

54.50%

Requested rate increase (decrease), amount

$ 321

Requested rate increase (decrease), amount related to recovery of investments

$ 59

Requested rate increase, projected test year, term

12 months

Requested rate increase (decrease), additional amount

$ 32

Requested rate increase (decrease), proposed riders | rider

3

Nicor Gas | Investing In Illinois

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase amount recovery of investments

$ 94

Atlanta Gas Light

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ (43)

$ (5)

Authorized ROE

10.25%

Public utilities, maximum base rate percentage

5%

5%

Requested rate increase (decrease), amount

$ 37.6

Requested rate increase, projected test year, term

12 months

Integrated capacity delivery plan, interstate and intrastate capacity asset requirements, term

10 years

Integrated capacity delivery plan, interstate and intrastate capacity asset requirements, detailed plan term

3 years

Integrated capacity delivery plan, capital budgets and related operations and maintenance spending, term

10 years

10 years

Approved rate decrease, percent

10%

Integrated capacity delivery plan, capital forecast plan, years one through three

$ 1,700

Atlanta Gas Light | Scenario, Forecast

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ (7)

Atlanta Gas Light | Minimum

Public Utilities, General Disclosures [Line Items]

Authorized ROE

10.05%

Integrated capacity delivery plan, capital forecast plan, years one through ten

$ 500

Atlanta Gas Light | Maximum

Public Utilities, General Disclosures [Line Items]

Authorized ROE

10.45%

Integrated capacity delivery plan, capital forecast plan, years one through ten

$ 600

Virginia Natural Gas

Public Utilities, General Disclosures [Line Items]

Public utilities, approved rate increase (decrease), amount

$ 43

Public utilities, approved rate increase amount recovery of investments

$ 14

Authorized ROE

10.35%

9.50%

9.50%

Public utilities, approved equity capital structure, percentage

53.20%

51.90%

Requested rate increase (decrease), amount

$ 69

$ 50

Requested rate increase (decrease), amount related to recovery of investments

$ 15

Southern Company Gas [Member]

Public Utilities, General Disclosures [Line Items]

Requested rate increase (decrease), amount

$ 53

Net regulatory assets

$ (1,891)

$ (1,471)

REGULATORY MATTERS - GAS Sche_3

REGULATORY MATTERS - GAS Schedule of Unrecognized Ratemaking Amounts (Details) - Regulatory Asset Off Balance Sheet - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Atlanta Gas Light
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset	$ 35	$ 47
Virginia Natural Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset	10	10
Chattanooga Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset	2	4
Nicor Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset	3	0
Southern Company Gas
Schedule of Regulatory Assets and Liabilities [Line Items]
Regulatory asset	$ 50	$ 61

CONTINGENCIES, COMMITMENTS, A_3

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - GPC Litigation (Details) - claim		1 Months Ended
	Feb. 07, 2022	Oct. 31, 2021
Class Action Lawsuit | Pending Litigation | Georgia Power
Loss Contingencies [Line Items]
Number of additional complaints filed	7	7

CONTINGENCIES, COMMITMENTS, A_4

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - MPC Litigation (Details) - Purported Violations Of Mississippi Consumer Protection Act - Pending Litigation - Mississippi Power $ in Millions	1 Months Ended	12 Months Ended
	Mar. 31, 2019 plaintiff	Dec. 31, 2018 USD ($) plaintiff defendant
Schedule of Regulatory Assets and Liabilities [Line Items]
Number of plaintiffs | plaintiff	4	10
Loss contingency, number of defendants | defendant		3
Public utilities, underpayment of refunds | $		$ 23.5

CONTINGENCIES, COMMITMENTS, A_5

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Environmental Remediation (Details)	12 Months Ended
	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($) state site	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Georgia Power
Environmental Exit Cost [Line Items]
Costs recovered annually		$ 12,000,000	$ 12,000,000	$ 12,000,000
Environmental remediation liability, current		15,000,000	17,000,000
Accrued environmental remediation		0	0
Under recovered environmental remediation costs, other regulatory assets, current		5,000,000	12,000,000
Under recovered environmental remediation costs, other regulatory assets, deferred		20,000,000	23,000,000
Georgia Power | Scenario, Forecast
Environmental Exit Cost [Line Items]
Costs recovered annually	$ 5,000,000
Southern Company Gas
Environmental Exit Cost [Line Items]
Environmental remediation liability, current		49,000,000	52,000,000
Accrued environmental remediation		207,000,000	197,000,000
Under recovered environmental remediation costs, other regulatory assets, current		54,000,000	59,000,000
Under recovered environmental remediation costs, other regulatory assets, deferred		$ 215,000,000	208,000,000
Southern Company Gas | Manufactured Gas Plants
Environmental Exit Cost [Line Items]
Number of sites | site		40
Number of states in which subject to environmental remediation liabilities | state		4
Alabama Power
Environmental Exit Cost [Line Items]
Environmental remediation liability, current		$ 0	0
Southern Company
Environmental Exit Cost [Line Items]
Environmental remediation liability, current		65,000,000	69,000,000
Accrued environmental remediation		207,000,000	197,000,000
Under recovered environmental remediation costs, other regulatory assets, current		59,000,000	71,000,000
Under recovered environmental remediation costs, other regulatory assets, deferred		$ 235,000,000	231,000,000
Environmental Loss Contingency, Current, Statement of Financial Position [Extensible Enumeration]		Other Liabilities, Current
Mississippi Power [Member]
Environmental Exit Cost [Line Items]
Environmental remediation liability, current		$ 0	$ 0

CONTINGENCIES, COMMITMENTS, A_6

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Nuclear Fuel Disposal Costs and Nuclear Insurance (Details)	12 Months Ended	108 Months Ended
	Dec. 31, 2022 USD ($) plant	Dec. 31, 2019 USD ($)
Jointly Owned Utility Plant Interests [Line Items]
Maximum fund for public liability claims arising from a single nuclear incident under price - anderson amendments act	$ 13,700,000,000
Maximum insurance coverage provided by American Nuclear Insurers to each nuclear plant	450,000,000
Maximum amount that a company could be assessed per incident for each licensed reactor	138,000,000
Maximum aggregate amount that a reactor can assess in a calendar period for each incident	$ 20,000,000
Block period considered for inflation adjustment against maximum assessment per reactor	5 years
Maximum deductible waiting period	182 days
Maximum coverage per occurrence per unit limit to obtain replacement power	$ 490,000,000
Aggregate payment for claims resulting from terrorist acts in one year period	3,200,000,000
Vogtle Units 3 and 4
Jointly Owned Utility Plant Interests [Line Items]
Maximum limits for accidental property damage occurring during construction	$ 2,750,000,000
Alabama Power and Georgia Power
Jointly Owned Utility Plant Interests [Line Items]
Number of nuclear fuel plants | plant	3
Maximum property damage insurance provided to nuclear generating facilities	$ 1,500,000,000
Maximum additional coverage provided for losses under excess insurance	1,250,000,000
Maximum additional coverage provided for losses under excess insurance, non-nuclear losses	$ 750,000,000
Elected deductible waiting period	84 days
Alabama Power
Jointly Owned Utility Plant Interests [Line Items]
Maximum assessment, excluding any applicable state premium taxes	$ 275,000,000
Maximum aggregate amount to be paid in one year	41,000,000
Current maximum annual assessments under NEIL policies	51,000,000
Alabama Power | Positive Outcome of Litigation
Jointly Owned Utility Plant Interests [Line Items]
Outstanding claims		$ 110,000,000
Georgia Power
Jointly Owned Utility Plant Interests [Line Items]
Maximum assessment, excluding any applicable state premium taxes	330,000,000
Maximum aggregate amount to be paid in one year	49,000,000
Current maximum annual assessments under NEIL policies	$ 85,000,000
Georgia Power | Positive Outcome of Litigation
Jointly Owned Utility Plant Interests [Line Items]
Outstanding claims		$ 132,000,000

CONTINGENCIES, COMMITMENTS, A_7

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - APC Litigation (Details) - Alabama Power - AT&T $ in Millions	1 Months Ended
	Apr. 30, 2019 USD ($)
Loss Contingencies [Line Items]
Potential refund amount owed	$ 87
Refund payment period	6 years

CONTINGENCIES, COMMITMENTS, A_8

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - MPC Other Matters (Details)		12 Months Ended					60 Months Ended
	Aug. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2025 USD ($)	Jan. 15, 2024 USD ($)	Jul. 12, 2022 claim	Dec. 31, 2016 USD ($)	Dec. 31, 2010 USD ($)
Loss Contingencies [Line Items]
Period costs		$ 36,000,000	$ 26,000,000
Mississippi Power
Loss Contingencies [Line Items]
Period costs		0	0
Estimate of possible loss	$ 28,000,000
Kemper County energy facility assets, net | Mississippi Power
Loss Contingencies [Line Items]
Pre-tax charge to income		15,000,000	11,000,000	$ 4,000,000
After tax charge to income		$ 12,000,000	$ 8,000,000	$ 3,000,000
Government grants expected										$ 137,000,000	$ 270,000,000
Government grants received						$ 387,000,000
Plant Daniel | Mississippi Power
Loss Contingencies [Line Items]
Plant units | claim									2
Plant Daniel Unit, Primary | Mississippi Power
Loss Contingencies [Line Items]
Plant units | claim									1
Scenario, Forecast | Kemper County energy facility assets, net | Mississippi Power | Maximum
Loss Contingencies [Line Items]
Period costs							$ 15,000,000
Scenario, Forecast | Plant Daniel | Mississippi Power
Loss Contingencies [Line Items]
Payments to acquire businesses								$ 1
Business combination, option to purchase, period								120 days
Scenario, Forecast | Plant Daniel | Gulf Power
Loss Contingencies [Line Items]
Percent ownership in individual unit								100%
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Gulf Power
Loss Contingencies [Line Items]
Proceeds from divestiture of businesses, amount held back					$ 75,000,000

CONTINGENCIES, COMMITMENTS, A_9

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Commitments (Details) - Georgia Power - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
MEAG Power
Loss Contingencies [Line Items]
Percent ownership	5%
Plant Vogtle Units 1 and 2
Loss Contingencies [Line Items]
Capacity payments	$ 4	$ 6	$ 5
Recorded Unconditional Purchase Obligation, Fiscal Year Maturity Schedule [Abstract]
Recorded unconditional purchase obligation	41
Recorded unconditional purchase obligation, year one	3
Recorded unconditional purchase obligation, year two	4
Recorded unconditional purchase obligation, year three	4
Recorded unconditional purchase obligation, year four	4
Recorded unconditional purchase obligation, year five	2
Recorded unconditional purchase obligation, after year five	$ 26

CONTINGENCIES, COMMITMENTS, _10

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - GAS Commitments (Details) - Southern Company Gas MMBTU in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) MMBTU
Long-term Purchase Commitment [Line Items]
Natural gas pipeline capacity | MMBTU	34
Long-term purchase commitment amount	$ 157
Pipeline Charges, Storage Capacity, and Gas Supply
Pipeline Charges, Storage Capacity, and Gas Supply
2023	637
2024	455
2025	390
2026	212
2027	134
Thereafter	871
Total	$ 2,699

CONTINGENCIES, COMMITMENTS, _11

CONTINGENCIES, COMMITMENTS, AND GUARANTEES - Guarantees (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Recorded Unconditional Purchase Obligation [Line Items]
Short-term debt	$ 2,609	$ 1,440
Alabama Power
Recorded Unconditional Purchase Obligation [Line Items]
Jointly owned affiliate equity	80
Jointly owned affiliate long term debt	100
SEGCO | Alabama Power
Recorded Unconditional Purchase Obligation [Line Items]
Guarantee of unsecured senior notes	100
Short-term debt	$ 17

REVENUE FROM CONTRACTS WITH C_3

REVENUE FROM CONTRACTS WITH CUSTOMERS - Disaggregate Revenue Sources (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 25,941	$ 23,463	$ 21,097
Total operating revenues	29,279	23,113	20,375
Retail electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	15,839	14,244	13,677
Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,604	6,207	6,113
Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,369	4,877	4,699
Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,764	3,067	2,775
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	102	93	90
Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,218	3,625	2,888
Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,843	1,799	1,338
Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	763	470	340
Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,186	1,038	971
Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	84	49	30
Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	342	269	209
Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,120	1,851	1,399
PPA energy revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,274	1,122	735
PPA capacity revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	596	493	454
Non-PPA revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	250	236	210
Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	687	2,668	2,151
Wholesale gas services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers		2,168	1,727
Gas marketing services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	636	464	391
Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	51	36	33
Other revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,077	1,075	982
Other revenue sources
Disaggregation of Revenue [Line Items]
Other	3,338	3,349	3,764
Other adjustments
Disaggregation of Revenue [Line Items]
Other		(3,699)	(4,486)
Alabama Power
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	6,921	6,141	5,646
Total operating revenues	7,817	6,413	5,830
Alabama Power | Retail electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,844	5,470	5,203
Alabama Power | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,638	2,467	2,377
Alabama Power | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,685	1,600	1,512
Alabama Power | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,507	1,386	1,293
Alabama Power | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	14	17	21
Alabama Power | Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power | Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power | Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	883	469	284
Alabama Power | PPA energy revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	489	184	133
Alabama Power | PPA capacity revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	194	115	108
Alabama Power | Non-PPA revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	200	170	43
Alabama Power | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power | Wholesale gas services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers		0	0
Alabama Power | Gas marketing services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Alabama Power | Other revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	194	202	159
Alabama Power | Other revenue sources
Disaggregation of Revenue [Line Items]
Other	896	272	184
Alabama Power | Other adjustments
Disaggregation of Revenue [Line Items]
Other		0	0
Georgia Power
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	9,702	8,563	8,215
Total operating revenues	11,584	9,260	8,309
Georgia Power | Retail electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	9,049	7,940	7,666
Georgia Power | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,664	3,471	3,476
Georgia Power | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	3,385	3,010	2,933
Georgia Power | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,921	1,391	1,197
Georgia Power | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	79	68	60
Georgia Power | Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power | Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power | Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	207	171	102
Georgia Power | PPA energy revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	130	95	42
Georgia Power | PPA capacity revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	47	55	50
Georgia Power | Non-PPA revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	30	21	10
Georgia Power | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power | Wholesale gas services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers		0	0
Georgia Power | Gas marketing services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Georgia Power | Other revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	446	452	447
Georgia Power | Other revenue sources
Disaggregation of Revenue [Line Items]
Other	1,882	697	94
Georgia Power | Other adjustments
Disaggregation of Revenue [Line Items]
Other		0	0
Mississippi Power
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,703	1,282	1,157
Total operating revenues	1,694	1,322	1,172
Mississippi Power | Retail electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	946	834	808
Mississippi Power | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	302	269	260
Mississippi Power | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	299	267	254
Mississippi Power | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	336	290	285
Mississippi Power | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	9	8	9
Mississippi Power | Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power | Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power | Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	710	417	323
Mississippi Power | PPA energy revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	16	11	9
Mississippi Power | PPA capacity revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	4	5	3
Mississippi Power | Non-PPA revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	690	401	311
Mississippi Power | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power | Wholesale gas services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers		0	0
Mississippi Power | Gas marketing services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Mississippi Power | Other revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	47	31	26
Mississippi Power | Other revenue sources
Disaggregation of Revenue [Line Items]
Other	(9)	40	15
Mississippi Power | Other adjustments
Disaggregation of Revenue [Line Items]
Other		0	0
Southern Power
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,805	1,605	1,119
Total operating revenues	3,369	2,216	1,733
Southern Power | Retail electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,769	1,575	1,105
Southern Power | PPA energy revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,673	854	570
Southern Power | PPA capacity revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	356	323	296
Southern Power | Non-PPA revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	740	398	239
Southern Power | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Wholesale gas services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers		0	0
Southern Power | Gas marketing services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Power | Other revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	36	30	14
Southern Power | Other revenue sources
Disaggregation of Revenue [Line Items]
Other	564	611	614
Southern Power | Other adjustments
Disaggregation of Revenue [Line Items]
Other		0	0
Southern Company Gas
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,905	6,293	5,039
Total operating revenues	5,962	4,380	3,434
Southern Company Gas | Retail electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas | Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	5,218	3,625	2,888
Southern Company Gas | Residential
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	2,843	1,799	1,338
Southern Company Gas | Commercial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	763	470	340
Southern Company Gas | Transportation
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,186	1,038	971
Southern Company Gas | Industrial
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	84	49	30
Southern Company Gas | Other
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	342	269	209
Southern Company Gas | Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas | PPA energy revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas | PPA capacity revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas | Non-PPA revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	687	2,668	2,151
Southern Company Gas | Wholesale gas services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers		2,168	1,727
Southern Company Gas | Gas marketing services
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	636	464	391
Southern Company Gas | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	51	36	33
Southern Company Gas | Other revenues
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	0	0	0
Southern Company Gas | Other revenue sources
Disaggregation of Revenue [Line Items]
Other	$ 57	1,786	2,881
Southern Company Gas | Other adjustments
Disaggregation of Revenue [Line Items]
Other		$ (3,699)	$ (4,486)

REVENUE FROM CONTRACTS WITH C_4

REVENUE FROM CONTRACTS WITH CUSTOMERS - Contract Balances (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Accounts Receivable	$ 3,123	$ 2,504
Contract Assets	156	117
Contract Liabilities	45	57
Contract with customer, liability, revenue recognized	36	29
Unregulated Distributed Generation
Disaggregation of Revenue [Line Items]
Contract Assets	65	50
Contract Liabilities	32	39
Alabama Power
Disaggregation of Revenue [Line Items]
Accounts Receivable	696	589
Contract Assets	2	2
Contract Liabilities	4	4
Georgia Power
Disaggregation of Revenue [Line Items]
Accounts Receivable	922	736
Contract Assets	89	63
Contract Liabilities	9	14
Mississippi Power
Disaggregation of Revenue [Line Items]
Accounts Receivable	92	73
Contract Assets	0	0
Contract Liabilities	0	0
Southern Power
Disaggregation of Revenue [Line Items]
Accounts Receivable	237	149
Contract Assets	0	1
Contract Liabilities	1	1
Southern Company Gas
Disaggregation of Revenue [Line Items]
Accounts Receivable	1,107	753
Contract Assets	0	0
Contract Liabilities	$ 0	$ 0

REVENUE FROM CONTRACTS WITH C_5

REVENUE FROM CONTRACTS WITH CUSTOMERS - Performance Obligations (Details) $ in Millions	Dec. 31, 2022 USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 640
Expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 483
Expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 332
Expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 311
Expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 315
Expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 2,076
Expected timing of satisfaction
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 24
Expected timing of satisfaction	1 year
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 7
Expected timing of satisfaction	1 year
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 6
Expected timing of satisfaction	1 year
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction	1 year
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction	1 year
Alabama Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 74
Expected timing of satisfaction	1 year
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 39
Expected timing of satisfaction	1 year
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 22
Expected timing of satisfaction	1 year
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 11
Expected timing of satisfaction	1 year
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 10
Expected timing of satisfaction	1 year
Georgia Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 10
Expected timing of satisfaction
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 355
Expected timing of satisfaction	1 year
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 345
Expected timing of satisfaction	1 year
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 302
Expected timing of satisfaction	1 year
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 303
Expected timing of satisfaction	1 year
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 310
Expected timing of satisfaction	1 year
Southern Power | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 2,077
Expected timing of satisfaction
Southern Company Gas | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 34
Expected timing of satisfaction	1 year
Southern Company Gas | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 29
Expected timing of satisfaction	1 year
Southern Company Gas | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction	1 year
Southern Company Gas | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction	1 year
Southern Company Gas | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2027-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction	1 year
Southern Company Gas | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
Expected timing of satisfaction

PROPERTY, PLANT, AND EQUIPMEN_2

PROPERTY, PLANT, AND EQUIPMENT - Property, Plant and Equipment (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Electric utilities:
Generation	$ 51,756	$ 53,803
Transmission	14,201	13,406
Distribution	24,200	22,236
General/other	5,806	5,423
Electric utilities' plant in service	95,963	94,868
Southern Company Gas:
Natural gas distribution utilities transportation and distribution	16,810	15,714
Storage facilities	1,553	1,315
Other	1,360	1,851
Southern Company Gas plant in service	19,723	18,880
Other plant in service	1,843	1,844
Total plant in service	117,529	115,592
Alabama Power
Electric utilities:
Generation	15,920	16,631
Transmission	5,658	5,334
Distribution	9,154	8,643
General/other	2,740	2,527
Electric utilities' plant in service	33,472	33,135
Southern Company Gas:
Natural gas distribution utilities transportation and distribution	0	0
Storage facilities	0	0
Other	0	0
Southern Company Gas plant in service	0	0
Other plant in service	0	0
Total plant in service	33,472	33,135
Georgia Power
Electric utilities:
Generation	17,755	19,184
Transmission	7,576	7,132
Distribution	13,819	12,437
General/other	2,729	2,579
Electric utilities' plant in service	41,879	41,332
Southern Company Gas:
Natural gas distribution utilities transportation and distribution	0	0
Storage facilities	0	0
Other	0	0
Southern Company Gas plant in service	0	0
Other plant in service	0	0
Total plant in service	41,879	41,332
Mississippi Power
Electric utilities:
Generation	2,826	2,791
Transmission	927	900
Distribution	1,228	1,156
General/other	273	259
Electric utilities' plant in service	5,254	5,106
Southern Company Gas:
Natural gas distribution utilities transportation and distribution	0	0
Storage facilities	0	0
Other	0	0
Southern Company Gas plant in service	0	0
Other plant in service	0	0
Total plant in service	5,254	5,106
Southern Power
Electric utilities:
Generation	14,619	14,551
Transmission	0	0
Distribution	0	0
General/other	39	34
Electric utilities' plant in service	14,658	14,585
Southern Company Gas:
Natural gas distribution utilities transportation and distribution	0	0
Storage facilities	0	0
Other	0	0
Southern Company Gas plant in service	0	0
Other plant in service	0	0
Total plant in service	14,658	14,585
Southern Company Gas
Electric utilities:
Generation	0	0
Transmission	0	0
Distribution	0	0
General/other	0	0
Electric utilities' plant in service	0	0
Southern Company Gas:
Natural gas distribution utilities transportation and distribution	16,810	15,714
Storage facilities	1,553	1,315
Other	1,360	1,851
Southern Company Gas plant in service	19,723	18,880
Other plant in service	0	0
Total plant in service	$ 19,723	$ 18,880

PROPERTY, PLANT, AND EQUIPMEN_3

PROPERTY, PLANT, AND EQUIPMENT - Additional Information (Narrative) (Details) - Nuclear Outage	12 Months Ended
	Dec. 31, 2022
Plant Farley | Alabama Power
Property, Plant and Equipment [Line Items]
Regulatory asset amortization period	18 months
Plant Vogtle Units 1 and 2 | Georgia Power
Property, Plant and Equipment [Line Items]
Regulatory asset amortization period	18 months
Plant Hatch Units 1 and 2 | Georgia Power | Maximum
Property, Plant and Equipment [Line Items]
Regulatory asset amortization period	24 months

PROPERTY, PLANT, AND EQUIPMEN_4

PROPERTY, PLANT, AND EQUIPMENT - Deferred Cloud Implementation Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Deferred cloud implementation costs	$ 20,148	$ 17,259
Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Deferred cloud implementation costs	345	240
Amortization	29	0
Alabama Power
Property, Plant and Equipment [Line Items]
Deferred cloud implementation costs	5,372	4,549
Alabama Power | Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Deferred cloud implementation costs	81	54
Amortization	8	0
Georgia Power
Property, Plant and Equipment [Line Items]
Deferred cloud implementation costs	11,117	8,823
Georgia Power | Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Deferred cloud implementation costs	108	81
Amortization	12	0
Mississippi Power
Property, Plant and Equipment [Line Items]
Deferred cloud implementation costs	828	877
Mississippi Power | Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Deferred cloud implementation costs	14	11
Amortization	0	0
Southern Power
Property, Plant and Equipment [Line Items]
Deferred cloud implementation costs	956	967
Southern Power | Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Deferred cloud implementation costs	18	14
Amortization	0	0
Southern Company Gas
Property, Plant and Equipment [Line Items]
Deferred cloud implementation costs	882	1,064
Southern Company Gas | Deferred Cloud Implementation Costs
Property, Plant and Equipment [Line Items]
Deferred cloud implementation costs	54	35
Amortization	$ 0	$ 0

PROPERTY, PLANT, AND EQUIPMEN_5

PROPERTY, PLANT, AND EQUIPMENT - Composite Straight-Line Rates (Details) - Utility plant in service	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Alabama Power
Property, Plant and Equipment [Line Items]
Composite rate	2.70%	2.70%	2.60%
Georgia Power
Property, Plant and Equipment [Line Items]
Composite rate	3.30%	3.30%	3%
Mississippi Power
Property, Plant and Equipment [Line Items]
Composite rate	3.40%	3.60%	3.70%
Southern Company Gas
Property, Plant and Equipment [Line Items]
Composite rate	2.70%	2.80%	2.80%

PROPERTY, PLANT, AND EQUIPMEN_6

PROPERTY, PLANT, AND EQUIPMENT - Depreciation and Amortization (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 35,297	$ 34,079
Utility plant in service
Property, Plant and Equipment [Line Items]
Accumulated depreciation	34,300	33,100
Other plant in service
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 963	930
Other plant in service | Maximum
Property, Plant and Equipment [Line Items]
Depreciation period of original cost	30 years
Southern Company Gas
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 5,276	5,067
Southern Company Gas | Utility plant in service
Property, Plant and Equipment [Line Items]
Accumulated depreciation	5,100	4,800
Southern Company Gas | Other plant in service
Property, Plant and Equipment [Line Items]
Accumulated depreciation	$ 184	$ 219
Southern Company Gas | Transportation equipment | Minimum
Property, Plant and Equipment [Line Items]
Depreciation period of original cost	5 years
Southern Company Gas | Transportation equipment | Maximum
Property, Plant and Equipment [Line Items]
Depreciation period of original cost	12 years
Southern Company Gas | Storage facilities | Minimum
Property, Plant and Equipment [Line Items]
Depreciation period of original cost	30 years
Southern Company Gas | Storage facilities | Maximum
Property, Plant and Equipment [Line Items]
Depreciation period of original cost	75 years
Southern Company Gas | Other assets | Maximum
Property, Plant and Equipment [Line Items]
Depreciation period of original cost	75 years

PROPERTY, PLANT, AND EQUIPMEN_7

PROPERTY, PLANT, AND EQUIPMENT - Southern Power Useful Lives (Details) - Southern Power - Maximum	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Natural Gas Generating Facility
Property, Plant and Equipment [Line Items]
Useful life	50 years
Solar Generating Facility
Property, Plant and Equipment [Line Items]
Useful life	35 years	30 years
Wind Generating Facility
Property, Plant and Equipment [Line Items]
Useful life	35 years

PROPERTY, PLANT, AND EQUIPMEN_8

PROPERTY, PLANT, AND EQUIPMENT - Ownership and Investment in Jointly-Owned Facilities (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) mi	Sep. 30, 2021
Alabama Power
Other Ownership Interests [Line Items]
Percent Ownership	14%
Alabama Power | Greene County (natural gas) Units 1 and 2
Other Ownership Interests [Line Items]
Percent Ownership	60%
Plant in Service	$ 193
Accumulated Depreciation	85
CWIP	$ 0
Alabama Power | Plant Miller (coal) Units 1 and 2
Other Ownership Interests [Line Items]
Percent Ownership	91.80%
Plant in Service	$ 2,148
Accumulated Depreciation	712
CWIP	$ 13
Georgia Power | Plant Hatch (nuclear)
Other Ownership Interests [Line Items]
Percent Ownership	50.10%
Plant in Service	$ 1,401
Accumulated Depreciation	671
CWIP	$ 62
Georgia Power | Plant Vogtle (nuclear) Units 1 and 2
Other Ownership Interests [Line Items]
Percent Ownership	45.70%
Plant in Service	$ 3,628
Accumulated Depreciation	2,298
CWIP	$ 94
Georgia Power | Plant Scherer (coal) Units 1 and 2
Other Ownership Interests [Line Items]
Percent Ownership	8.40%
Plant in Service	$ 276
Accumulated Depreciation	106
CWIP	$ 1
Georgia Power | Plant Scherer (coal) Unit 3
Other Ownership Interests [Line Items]
Percent Ownership	75%
Plant in Service	$ 1,317
Accumulated Depreciation	567
CWIP	$ 6
Georgia Power | Rocky Mountain (pumped storage)
Other Ownership Interests [Line Items]
Percent Ownership	25.40%
Plant in Service	$ 184
Accumulated Depreciation	153
CWIP	$ 1
Mississippi Power | Greene County (natural gas) Units 1 and 2
Other Ownership Interests [Line Items]
Percent Ownership	40%
Plant in Service	$ 125
Accumulated Depreciation	70
CWIP	$ 0
Mississippi Power | Plant Daniel (coal) Units 1 and 2
Other Ownership Interests [Line Items]
Percent Ownership	50%
Plant in Service	$ 765
Accumulated Depreciation	257
CWIP	$ 30
Southern Company Gas | Dalton Pipeline (natural gas pipeline)
Other Ownership Interests [Line Items]
Percent Ownership	50%
Plant in Service	$ 271
Accumulated Depreciation	23
CWIP	$ 0
Pipeline infrastructure (miles) | mi	115
Agreement to lease undivided ownership (percent)	50%
Future minimum payments receivable	$ 26
Plant Daniel | Mississippi Power
Other Ownership Interests [Line Items]
Percent Ownership		50%

PROPERTY, PLANT, AND EQUIPMEN_9

PROPERTY, PLANT, AND EQUIPMENT - Joint Ownership Agreements (Narrative) (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Property, Plant and Equipment [Line Items]
Construction work in progress	$ 10,896	$ 8,771
Georgia Power
Property, Plant and Equipment [Line Items]
Construction work in progress	$ 8,103	$ 6,688
Plant Vogtle Units 3 and 4 | Georgia Power
Property, Plant and Equipment [Line Items]
Percent ownership	45.70%
Construction work in progress	$ 9,700

PROPERTY, PLANT, AND EQUIPME_10

PROPERTY, PLANT, AND EQUIPMENT - Assets Subject to Lien (Narrative) (Details) $ in Millions	Dec. 31, 2022 USD ($)
Mississippi Power | Chevron
Property, Plant and Equipment [Line Items]
Net book value of co-generation assets	$ 157

ASSET RETIREMENT OBLIGATIONS -

ASSET RETIREMENT OBLIGATIONS - Details of AROs Included in the Balance Sheets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year	$ 11,687	$ 10,684
Liabilities incurred	36	26
Liabilities settled	(455)	(456)
Accretion	406	407
Cash flow revisions	(834)	1,026
Balance at end of year	10,840	11,687
Alabama Power
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year	4,334	3,974
Liabilities incurred	0	0
Liabilities settled	(205)	(202)
Accretion	158	156
Cash flow revisions	0	406
Balance at end of year	4,287	4,334
Georgia Power
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year	6,824	6,265
Liabilities incurred	35	3
Liabilities settled	(212)	(210)
Accretion	231	236
Cash flow revisions	(844)	530
Balance at end of year	6,034	6,824
Mississippi Power
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year	190	176
Liabilities incurred	0	0
Liabilities settled	(20)	(24)
Accretion	6	7
Cash flow revisions	3	31
Balance at end of year	179	190
Southern Power
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at beginning of year	131	95
Liabilities incurred	0	23
Liabilities settled	0	0
Accretion	6	5
Cash flow revisions	7	8
Balance at end of year	$ 144	$ 131

ASSET RETIREMENT OBLIGATIONS _2

ASSET RETIREMENT OBLIGATIONS - Narrative (Details) - USD ($)		1 Months Ended	12 Months Ended
	Jan. 01, 2023	Dec. 31, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2019	Dec. 31, 2020
Jointly Owned Utility Plant Interests [Line Items]
Cash flow revisions			$ (834,000,000)	$ 1,026,000,000
Asset retirement obligations		$ 10,840,000,000	10,840,000,000	11,687,000,000		$ 10,684,000,000
Alabama Power
Jointly Owned Utility Plant Interests [Line Items]
Cash flow revisions			$ 0	406,000,000
Estimated inflation rate			4.50%
Estimated trust earnings rate			7%
Asset retirement obligations		4,287,000,000	$ 4,287,000,000	4,334,000,000		3,974,000,000
Alabama Power | Internal reserves
Jointly Owned Utility Plant Interests [Line Items]
Accumulated provisions for decommissioning		14,000,000	$ 14,000,000	15,000,000
Alabama Power | Plant Farley
Jointly Owned Utility Plant Interests [Line Items]
Site-specific estimate of decommissioning costs, period of updates made			5 years
Georgia Power
Jointly Owned Utility Plant Interests [Line Items]
Cash flow revisions			$ (844,000,000)	530,000,000
Fair market value of securities on loan and pledged to creditors		35,000,000	35,000,000	42,000,000
Fair value of collateral received		36,000,000	$ 36,000,000	43,000,000
Estimated inflation rate			2.50%
Estimated trust earnings rate			4.50%
Asset retirement obligations		6,034,000,000	$ 6,034,000,000	6,824,000,000		6,265,000,000
Georgia Power | CCR AROs
Jointly Owned Utility Plant Interests [Line Items]
Cash flow revisions		(780,000,000)		435,000,000
Georgia Power | Plant Hatch and Plant Vogtle Units 1 And 2
Jointly Owned Utility Plant Interests [Line Items]
Annual decommissioning cost for ratemaking					$ 4,000,000
Georgia Power | Plant Hatch and Plant Vogtle Units 1 And 2 | Scenario, Forecast
Jointly Owned Utility Plant Interests [Line Items]
Annual decommissioning cost for ratemaking	$ 0
Mississippi Power
Jointly Owned Utility Plant Interests [Line Items]
Cash flow revisions			3,000,000	31,000,000
Asset retirement obligations		$ 179,000,000	$ 179,000,000	$ 190,000,000		$ 176,000,000

ASSET RETIREMENT OBLIGATIONS _3

ASSET RETIREMENT OBLIGATIONS - Investment Securities in the Funds (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Marketable Securities [Line Items]
Total investment securities in the Funds	$ 2,143	$ 2,541
Equity securities
Marketable Securities [Line Items]
Total investment securities in the Funds	1,095	1,358
Debt securities
Marketable Securities [Line Items]
Total investment securities in the Funds	838	986
Other securities
Marketable Securities [Line Items]
Total investment securities in the Funds	210	197
Alabama Power
Marketable Securities [Line Items]
Total investment securities in the Funds	1,125	1,324
Alabama Power | Equity securities
Marketable Securities [Line Items]
Total investment securities in the Funds	690	849
Alabama Power | Debt securities
Marketable Securities [Line Items]
Total investment securities in the Funds	267	316
Alabama Power | Other securities
Marketable Securities [Line Items]
Total investment securities in the Funds	168	159
Georgia Power
Marketable Securities [Line Items]
Total investment securities in the Funds	1,018	1,217
Georgia Power | Equity securities
Marketable Securities [Line Items]
Total investment securities in the Funds	405	509
Georgia Power | Debt securities
Marketable Securities [Line Items]
Total investment securities in the Funds	571	670
Georgia Power | Other securities
Marketable Securities [Line Items]
Total investment securities in the Funds	$ 42	$ 38

ASSET RETIREMENT OBLIGATIONS _4

ASSET RETIREMENT OBLIGATIONS - Fair Value Increases (Decreases) of the Funds (Details) - Securities held in the Funds - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair value increases (decreases)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Fair value increases (decreases) of the Funds	$ (360)	$ 274	$ 280
Unrealized gains (losses)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Fair value increases (decreases) of the Funds	(391)	(27)	220
Alabama Power | Fair value increases (decreases)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Fair value increases (decreases) of the Funds	(171)	200	142
Alabama Power | Unrealized gains (losses)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Fair value increases (decreases) of the Funds	(204)	(30)	121
Georgia Power | Fair value increases (decreases)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Fair value increases (decreases) of the Funds	(189)	74	138
Georgia Power | Unrealized gains (losses)
Fair Value, Measured on Recurring Basis, Gain (Loss) Included in Earnings [Line Items]
Fair value increases (decreases) of the Funds	$ (187)	$ 3	$ 99

ASSET RETIREMENT OBLIGATIONS _5

ASSET RETIREMENT OBLIGATIONS - Accumulated Provisions for the External Decommissioning Trust Funds (Details) - External decommissioning trust funds - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Georgia Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	$ 1,018	$ 1,217
Plant Farley | Alabama Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	1,125	1,324
Plant Hatch | Georgia Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	628	757
Plant Vogtle Units 1 and 2 | Georgia Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	382	460
Plant Vogtle Unit 3 | Georgia Power
Public Utilities, General Disclosures [Line Items]
Accumulated provisions for decommissioning	$ 8	$ 0

ASSET RETIREMENT OBLIGATIONS _6

ASSET RETIREMENT OBLIGATIONS - Estimated Costs of Decommissioning (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)
Alabama Power | Plant Farley
Public Utilities, General Disclosures [Line Items]
Decommissioning periods: Beginning year	2037
Decommissioning periods: Completion year	2076
Site study costs	$ 1,720
Alabama Power | Radiated structures | Plant Farley
Public Utilities, General Disclosures [Line Items]
Site study costs	1,234
Alabama Power | Spent fuel management | Plant Farley
Public Utilities, General Disclosures [Line Items]
Site study costs	387
Alabama Power | Non-radiated structures | Plant Farley
Public Utilities, General Disclosures [Line Items]
Site study costs	$ 99
Georgia Power | Plant Hatch
Public Utilities, General Disclosures [Line Items]
Decommissioning periods: Beginning year	2034
Decommissioning periods: Completion year	2075
Site study costs	$ 1,018
Georgia Power | Plant Vogtle Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Decommissioning periods: Beginning year	2047
Decommissioning periods: Completion year	2079
Site study costs	$ 883
Georgia Power | Radiated structures | Plant Hatch
Public Utilities, General Disclosures [Line Items]
Site study costs	771
Georgia Power | Radiated structures | Plant Vogtle Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Site study costs	628
Georgia Power | Spent fuel management | Plant Hatch
Public Utilities, General Disclosures [Line Items]
Site study costs	186
Georgia Power | Spent fuel management | Plant Vogtle Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Site study costs	170
Georgia Power | Non-radiated structures | Plant Hatch
Public Utilities, General Disclosures [Line Items]
Site study costs	61
Georgia Power | Non-radiated structures | Plant Vogtle Units 1 and 2
Public Utilities, General Disclosures [Line Items]
Site study costs	$ 85

CONSOLIDATED ENTITIES AND EQU_3

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - Southern Company (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries	$ 1,443	$ 1,282
Southern Holdings Company
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries	$ 112	$ 101

CONSOLIDATED ENTITIES AND EQU_4

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - SEGCO Equity Method Investments Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) MW	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Alabama Power
Jointly Owned Utility Plant Interests [Line Items]
Percent ownership	14%
Alabama Power | SEGCO
Jointly Owned Utility Plant Interests [Line Items]
Ownership percentage, equity method investment	50%
Alabama Power | SEGCO
Jointly Owned Utility Plant Interests [Line Items]
Total megawatt capacity (in MWs) | MW	1,020
Share of purchased power	$ 124	$ 75	$ 67
Dividends paid by equity method investment	$ 14	14	12
Georgia Power | SEGCO
Jointly Owned Utility Plant Interests [Line Items]
Ownership percentage, equity method investment	50%
Georgia Power | SEGCO
Jointly Owned Utility Plant Interests [Line Items]
Share of purchased power	$ 127	$ 77	$ 69
SEGCO | Alabama Power
Jointly Owned Utility Plant Interests [Line Items]
Percent ownership	86%

CONSOLIDATED ENTITIES AND EQU_5

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - SPC Noncontrolling Interests and VIEs Narrative (Details) $ in Millions	2 Months Ended	12 Months Ended
	Feb. 15, 2023 USD ($)	Dec. 31, 2022 USD ($) investor	Dec. 31, 2019	Dec. 31, 2018 investor	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Redeemable Noncontrolling Interest [Line Items]
Assets		$ 134,891			$ 127,534	$ 122,935
Liabilities		100,359			94,967
Equity investments in unconsolidated subsidiaries		1,443			1,282
Southern Power
Redeemable Noncontrolling Interest [Line Items]
Assets		13,081			13,390
Liabilities		6,165			6,792
Equity investments in unconsolidated subsidiaries		49			86
Proceeds from sale of equity method investments		$ 38
Southern Power | Subsequent Event
Redeemable Noncontrolling Interest [Line Items]
Proceeds from sale of equity method investments	$ 50
Southern Power | SP Solar Holdings I, LP
Redeemable Noncontrolling Interest [Line Items]
Sale of equity interest in limited partnership			33%
Wholly Owned Subsidiary Of Southern Power | Southern Power | SP Solar Holdings I, LP
Redeemable Noncontrolling Interest [Line Items]
Ownership interest			66%
Wholly Owned Subsidiary Of Southern Power | Southern Power | SP Wind
Redeemable Noncontrolling Interest [Line Items]
Ownership interest				100%
SP Solar Holdings I, LP | Southern Power
Redeemable Noncontrolling Interest [Line Items]
Distribution made to limited partner, cash distributions paid, percentage		67%
SP Solar Holdings I, LP | Global Atlantic
Redeemable Noncontrolling Interest [Line Items]
Distribution made to limited partner, cash distributions paid, percentage		33%
SP Wind | Southern Power
Redeemable Noncontrolling Interest [Line Items]
Distribution made to limited partner, cash distributions paid, percentage		60%
Number of financial investors | investor		3		3
SP Wind | Financial Investors
Redeemable Noncontrolling Interest [Line Items]
Distribution made to limited partner, cash distributions paid, percentage		40%
General Partner | Wholly Owned Subsidiary Of Southern Power | Southern Power | SP Solar Holdings I, LP
Redeemable Noncontrolling Interest [Line Items]
Ownership interest			1%
Variable Interest Entity, Primary Beneficiary | SP Solar Holdings I, LP | Southern Power
Redeemable Noncontrolling Interest [Line Items]
Assets		$ 5,900			6,100
Liabilities		400
Noncontrolling interests related to other partners' interest		1,100
Variable Interest Entity, Primary Beneficiary | SP Wind | Southern Power
Redeemable Noncontrolling Interest [Line Items]
Assets		2,200			2,300
Liabilities		169			130
Noncontrolling interests related to other partners' interest		39			41
Variable Interest Entity, Primary Beneficiary | Other Variable Interest Entities | Southern Power
Redeemable Noncontrolling Interest [Line Items]
Assets		1,800			1,900
Liabilities		200			300
Noncontrolling interests related to other partners' interest		$ 800			$ 900

CONSOLIDATED ENTITIES AND EQU_6

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - Balance Sheet Information (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries			$ 1,443	$ 1,282
Impairment charges			251	2	$ 0
Southern Company Gas
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries			1,276	1,173
Impairment charges			131	0	$ 0
SNG | Southern Company Gas
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries			1,243	1,129
PennEast Pipeline | Southern Company Gas
Schedule of Equity Method Investments [Line Items]
Impairment charges	$ 2	$ 82	84	84
Dividends paid by equity method investment			11
Other | Southern Company Gas
Schedule of Equity Method Investments [Line Items]
Equity investments in unconsolidated subsidiaries			$ 33	$ 44

CONSOLIDATED ENTITIES AND EQU_7

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - Income Statement Information (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investments			$ 151	$ 76	$ 153
Impairment charges			251	2	0
Southern Company Gas
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investments			148	50	141
Impairment charges			131	0	0
Southern Company Gas | SNG
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investments			146	127	129
Southern Company Gas | PennEast Pipeline
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investments			0	(81)	7
Impairment charges	$ 2	$ 82	84	84
Southern Company Gas | Other
Schedule of Equity Method Investments [Line Items]
Earnings from equity method investments			$ 2	$ 4	$ 5

CONSOLIDATED ENTITIES AND EQU_8

CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS - GAS Equity Method Investments Narrative (Details) $ in Millions	3 Months Ended		12 Months Ended
	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2014 mi
Schedule of Equity Method Investments [Line Items]
Impairment charges			$ 251	$ 2	$ 0
Income taxes (benefit)			795	267	393
Southern Company Gas
Schedule of Equity Method Investments [Line Items]
Impairment charges			131	0	0
Income taxes (benefit)			$ 180	275	$ 173
Southern Company Gas | PennEast Pipeline
Schedule of Equity Method Investments [Line Items]
Ownership percentage, equity method investment			20%			20%
Pipeline infrastructure (miles) | mi						118
Impairment charges	$ 2	$ 82	$ 84	84
Impairment charges, after tax	$ 2	$ 58	$ 67	67
Income taxes (benefit)				$ 7

FINANCING - Long-Term Debt (Det

FINANCING - Long-Term Debt (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Debt Instrument [Line Items]
Long-term debt, gross	$ 54,600	$ 52,100
Finance lease obligations	314	215
Unamortized fair value adjustment	330	359
Unamortized debt premium (discount), net	(193)	(216)
Debt Issuance Costs, Net	(273)	(243)
Unamortized debt issuance expense	(273)	(243)
Total long-term debt	54,941	52,277
Less: Amount due within one year	4,285	2,157
Long-Term Debt	$ 50,656	50,120
Senior notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.87%
Long-term debt, gross	$ 35,683	33,120
Junior subordinated notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.58%
Long-term debt, gross	$ 8,836	8,918
FFB loans
Debt Instrument [Line Items]
Weighted Average Interest Rate	2.88%
Long-term debt, gross	$ 4,874	4,962
Pollution control revenue bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.25%
Long-term debt, gross	$ 2,844	2,662
First mortgage bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.46%
Long-term debt, gross	$ 2,275	2,100
Medium-term notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	7.03%
Long-term debt, gross	$ 84	130
Other long-term debt
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.96%
Long-term debt, gross	$ 167	270
Alabama Power
Debt Instrument [Line Items]
Long-term debt, gross	10,600	9,700
Finance lease obligations	5	4
Unamortized debt premium (discount), net	(18)	(18)
Debt Issuance Costs, Net	(72)	(64)
Unamortized debt issuance expense	(72)	(64)
Total long-term debt	10,630	9,687
Less: Amount due within one year	301	751
Long-Term Debt	$ 10,329	8,936
Alabama Power | Senior notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.86%
Long-term debt, gross	$ 9,675	8,725
Alabama Power | Pollution control revenue bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.44%
Long-term debt, gross	$ 995	995
Alabama Power | Other long-term debt
Debt Instrument [Line Items]
Weighted Average Interest Rate	5.62%
Long-term debt, gross	$ 45	45
Georgia Power
Debt Instrument [Line Items]
Long-term debt, gross	14,700	13,600
Finance lease obligations	238	136
Unamortized debt premium (discount), net	(18)	(11)
Debt Issuance Costs, Net	(117)	(114)
Unamortized debt issuance expense	(117)	(114)
Total long-term debt	14,910	13,784
Less: Amount due within one year	901	675
Long-Term Debt	$ 14,009	13,109
Georgia Power | Senior notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.90%
Long-term debt, gross	$ 7,925	6,825
Georgia Power | Junior subordinated notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	5%
Long-term debt, gross	$ 270	270
Georgia Power | FFB loans
Debt Instrument [Line Items]
Weighted Average Interest Rate	2.88%
Long-term debt, gross	$ 4,874	4,962
Georgia Power | Pollution control revenue bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.13%
Long-term debt, gross	$ 1,738	1,591
Georgia Power | Other long-term debt
Debt Instrument [Line Items]
Long-term debt, gross	0	125
Mississippi Power
Debt Instrument [Line Items]
Long-term debt, gross	1,500	1,500
Finance lease obligations	17	18
Unamortized debt premium (discount), net	2	2
Debt Issuance Costs, Net	(10)	(10)
Unamortized debt issuance expense	(10)	(10)
Total long-term debt	1,545	1,511
Less: Amount due within one year	1	1
Long-Term Debt	$ 1,544	1,510
Mississippi Power | Senior notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.93%
Long-term debt, gross	$ 1,425	1,425
Mississippi Power | Pollution control revenue bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.55%
Long-term debt, gross	$ 111	76
Southern Power
Debt Instrument [Line Items]
Long-term debt, gross	3,000	3,700
Finance lease obligations	0	0
Unamortized debt premium (discount), net	(5)	(6)
Debt Issuance Costs, Net	(14)	(17)
Unamortized debt issuance expense	(14)	(17)
Total long-term debt	2,979	3,688
Less: Amount due within one year	290	679
Long-Term Debt	2,689	3,009
Fair value gain (loss)	$ (31)	5
Southern Power | Senior notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.92%
Long-term debt, gross	$ 2,998	3,711
Southern Company Gas
Debt Instrument [Line Items]
Long-term debt, gross	7,400	6,900
Finance lease obligations	0	0
Unamortized fair value adjustment	330	359
Unamortized debt premium (discount), net	(8)	(35)
Debt Issuance Costs, Net	(30)	0
Unamortized debt issuance expense	(30)	0
Total long-term debt	7,442	6,902
Less: Amount due within one year	400	47
Long-Term Debt	$ 7,042	6,855
Southern Company Gas | Senior notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	4.08%
Long-term debt, gross	$ 4,769	4,348
Southern Company Gas | First mortgage bonds
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.46%
Long-term debt, gross	$ 2,275	2,100
Southern Company Gas | Medium-term notes
Debt Instrument [Line Items]
Weighted Average Interest Rate	7.03%
Long-term debt, gross	$ 84	130
Southern Company Gas | Other long-term debt
Debt Instrument [Line Items]
Weighted Average Interest Rate	3.81%
Long-term debt, gross	$ 22	$ 0

FINANCING - Maturities of Long-

FINANCING - Maturities of Long-Term Debt (Details) $ in Millions	Dec. 31, 2022 USD ($)
Debt Instrument [Line Items]
2023	$ 4,293
2024	2,280
2025	1,699
2026	3,726
2027	2,074
Alabama Power
Debt Instrument [Line Items]
2023	301
2024	23
2025	251
2026	46
2027	550
Georgia Power
Debt Instrument [Line Items]
2023	901
2024	499
2025	145
2026	445
2027	510
Mississippi Power
Debt Instrument [Line Items]
2023	1
2024	201
2025	12
2026	1
2027	11
Southern Power
Debt Instrument [Line Items]
2023	290
2024	0
2025	500
2026	964
2027	0
Southern Power | Euro-denominated Debt
Debt Instrument [Line Items]
2027	564
Southern Company Gas
Debt Instrument [Line Items]
2023	400
2024	0
2025	300
2026	530
2027	$ 154

FINANCING - DOE Loan Guarantee

FINANCING - DOE Loan Guarantee Borrowings (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Remaining borrowing capacity	$ 7,596,000,000
Line of credit facility, maximum borrowing capacity	7,655,000,000
Georgia Power
Debt Instrument [Line Items]
Percent of eligible project costs (may not exceed)				70%
Remaining borrowing capacity	1,726,000,000
Principal amortization payments	88,000,000	$ 96,000,000	$ 73,000,000
Line of credit facility, maximum borrowing capacity	$ 1,750,000,000
Basis spread on variable rate	0.375%
Amortization period	5 years
FFB Credit Facility | Georgia Power
Debt Instrument [Line Items]
Eligible project costs to be reimbursed				$ 5,130,000,000
Funds received under guarantee settlement agreement, less customer refunds				$ 1,492,000,000
Remaining borrowing capacity		0
Principal amortization payments	$ 88,000,000
Line of credit facility, maximum borrowing capacity	$ 4,900,000,000	$ 5,000,000,000
Plant Vogtle Units 3 and 4 | Georgia Power
Debt Instrument [Line Items]
Percent ownership	45.70%
Ownership interest percentage required for voting for continuing construction	90%

FINANCING - Equity Units (Detai

FINANCING - Equity Units (Details) - USD ($) $ in Thousands		12 Months Ended
	Aug. 01, 2022	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020	May 31, 2022
Debt Instrument [Line Items]
Proceeds from issuance of common stock		$ 1,808,000	$ 73,000	$ 74,000
Series 2019A Remarketable Junior Subordinated Notes | Junior subordinated notes
Debt Instrument [Line Items]
Remarketed principal amount					$ 862,500
Quarterly interest rate					4.475%
Series 2019B Remarketable Junior Subordinated Notes | Junior subordinated notes
Debt Instrument [Line Items]
Remarketed principal amount					$ 862,500
Quarterly interest rate					5.113%
2019 Series A Equity Units | Junior subordinated notes
Debt Instrument [Line Items]
Common stock issued to settle purchase contracts (in shares)	25,200,000
Proceeds from issuance of common stock	$ 1,725,000

FINANCING - Bank Credit Arrange

FINANCING - Bank Credit Arrangements (Details)	Dec. 31, 2022 USD ($)
Line of Credit Facility [Line Items]
Expires, 2022	$ 280,000,000
Expires, 2023	700,000,000
Expires, 2024	125,000,000
Expires, 2025	6,550,000,000
Total	7,655,000,000
Unused	7,596,000,000
Due within One Year	280,000,000
Southern Company
Line of Credit Facility [Line Items]
Expires, 2022	0
Expires, 2023	0
Expires, 2024	0
Expires, 2025	2,000,000,000
Total	2,000,000,000
Unused	1,998,000,000
Due within One Year	0
Alabama Power
Line of Credit Facility [Line Items]
Expires, 2022	0
Expires, 2023	550,000,000
Expires, 2024	0
Expires, 2025	700,000,000
Total	1,250,000,000
Unused	1,250,000,000
Due within One Year	0
Georgia Power
Line of Credit Facility [Line Items]
Expires, 2022	0
Expires, 2023	0
Expires, 2024	0
Expires, 2025	1,750,000,000
Total	1,750,000,000
Unused	1,726,000,000
Due within One Year	0
Mississippi Power
Line of Credit Facility [Line Items]
Expires, 2022	0
Expires, 2023	150,000,000
Expires, 2024	125,000,000
Expires, 2025	0
Total	275,000,000
Unused	275,000,000
Due within One Year	0
Southern Power
Line of Credit Facility [Line Items]
Expires, 2022	0
Expires, 2023	0
Expires, 2024	0
Expires, 2025	600,000,000
Total	600,000,000
Unused	569,000,000
Due within One Year	0
Southern Power | Continuing Letter of Credit Facility A
Line of Credit Facility [Line Items]
Expires, 2024	75,000,000
Unused	9,000,000
Southern Power | Continuing Letter of Credit Facility B
Line of Credit Facility [Line Items]
Unused	5,000,000
Southern Company Gas
Line of Credit Facility [Line Items]
Expires, 2022	250,000,000
Expires, 2023	0
Expires, 2024	0
Expires, 2025	1,500,000,000
Total	1,750,000,000
Unused	1,748,000,000
Due within One Year	250,000,000
Other Subsidiaries
Line of Credit Facility [Line Items]
Expires, 2022	30,000,000
Expires, 2023	0
Expires, 2024	0
Expires, 2025	0
Total	30,000,000
Unused	30,000,000
Due within One Year	30,000,000
Southern Company Gas Capital
Line of Credit Facility [Line Items]
Total	800,000,000
Nicor Gas
Line of Credit Facility [Line Items]
Total	$ 700,000,000

FINANCING - Bank Credit Arran_2

FINANCING - Bank Credit Arrangements Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Line of Credit Facility [Line Items]
Ratio of indebtedness to capitalization, debt covenant, required	70%
Amount of variable rate pollution control revenue bonds outstanding requiring liquidity support	$ 1,700
Other Subsidiaries
Line of Credit Facility [Line Items]
Ratio of indebtedness to capitalization, debt covenant, required	65%
Alabama Power
Line of Credit Facility [Line Items]
Amount of variable rate pollution control revenue bonds outstanding requiring liquidity support	$ 789
Remarketed pollution control bonds	120
Georgia Power
Line of Credit Facility [Line Items]
Amount of variable rate pollution control revenue bonds outstanding requiring liquidity support	819
Remarketed pollution control bonds	288
Mississippi Power
Line of Credit Facility [Line Items]
Amount of variable rate pollution control revenue bonds outstanding requiring liquidity support	69
Southern Power | Power Purchase Agreement
Line of Credit Facility [Line Items]
Debt instrument, collateral amount	$ 106	$ 106

FINANCING - Notes Payable (Deta

FINANCING - Notes Payable (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Short-term Debt [Line Items]
Amount Outstanding	$ 2,609	$ 1,440
Weighted Average Interest Rate	4.90%	0.40%
Commercial paper
Short-term Debt [Line Items]
Amount Outstanding	$ 809	$ 1,140
Weighted Average Interest Rate	4.70%	0.30%
Short-term bank debt
Short-term Debt [Line Items]
Amount Outstanding	$ 1,800	$ 300
Weighted Average Interest Rate	5%	0.70%
Georgia Power
Short-term Debt [Line Items]
Amount Outstanding	$ 1,600	$ 0
Georgia Power | Short-term bank debt
Short-term Debt [Line Items]
Amount Outstanding	$ 1,600	$ 0
Weighted Average Interest Rate	5%	0%
Southern Power
Short-term Debt [Line Items]
Amount Outstanding	$ 225	$ 211
Southern Power | Commercial paper
Short-term Debt [Line Items]
Amount Outstanding	$ 225	$ 211
Weighted Average Interest Rate	4.70%	0.30%
Southern Company Gas
Short-term Debt [Line Items]
Amount Outstanding	$ 768	$ 1,209
Southern Company Gas | Commercial paper
Short-term Debt [Line Items]
Amount Outstanding	$ 768	$ 1,209
Weighted Average Interest Rate	4.70%	0.40%
Southern Company Gas Capital | Commercial paper
Short-term Debt [Line Items]
Amount Outstanding	$ 285	$ 379
Weighted Average Interest Rate	4.80%	0.30%
Nicor Gas | Commercial paper
Short-term Debt [Line Items]
Amount Outstanding	$ 283	$ 530
Weighted Average Interest Rate	4.60%	0.30%
Nicor Gas | Short-term bank debt
Short-term Debt [Line Items]
Amount Outstanding	$ 200	$ 300
Weighted Average Interest Rate	4.90%	0.70%

FINANCING - Outstanding Classes

FINANCING - Outstanding Classes of Capital Stock Narrative (Details) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) shares
Debt Instrument [Line Items]
Stock issued employee and director stock plans (in shares)	3.6
Proceeds from issuance of shares under share-based compensation plans | $	$ 83
Number of shares reserved for issuance to stock-based compensation plan (in shares)	113
Southern Company Common Stock
Debt Instrument [Line Items]
Remaining shares available for awards (in shares)	28.9

FINANCING - Diluted Earnings Pe

FINANCING - Diluted Earnings Per Share (Details) - shares shares in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Debt Disclosure [Abstract]
As reported shares (in shares)	1,075	1,061	1,058
Effect of stock-based compensation (in shares)	6	7	7
Diluted shares (in shares)	1,081	1,068	1,065

FINANCING - Preferred Stock Red

FINANCING - Preferred Stock Redemption (Details) - Alabama Power	12 Months Ended
	Dec. 31, 2022 $ / shares shares
4.92% Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0492
Par Value/Stated Capital Per Share (in dollars per share)	$ 100
Shares Outstanding (in shares) | shares	80,000
Redemption Price Per Share (in dollars per share)	$ 103.23
4.72% Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0472
Par Value/Stated Capital Per Share (in dollars per share)	$ 100
Shares Outstanding (in shares) | shares	50,000
Redemption Price Per Share (in dollars per share)	$ 102.18
4.64% Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0464
Par Value/Stated Capital Per Share (in dollars per share)	$ 100
Shares Outstanding (in shares) | shares	60,000
Redemption Price Per Share (in dollars per share)	$ 103.14
4.60% Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0460
Par Value/Stated Capital Per Share (in dollars per share)	$ 100
Shares Outstanding (in shares) | shares	100,000
Redemption Price Per Share (in dollars per share)	$ 104.20
4.52% Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0452
Par Value/Stated Capital Per Share (in dollars per share)	$ 100
Shares Outstanding (in shares) | shares	50,000
Redemption Price Per Share (in dollars per share)	$ 102.93
4.20% Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0420
Par Value/Stated Capital Per Share (in dollars per share)	$ 100
Shares Outstanding (in shares) | shares	135,115
Redemption Price Per Share (in dollars per share)	$ 105
5.00% Class A Preferred Stock
Debt Instrument, Redemption [Line Items]
Dividend rate percentage	0.0500
Par Value/Stated Capital Per Share (in dollars per share)	$ 25
Shares Outstanding (in shares) | shares	10,000,000
Redemption Price Per Share (in dollars per share)	$ 25

FINANCING - Dividend Restrictio

FINANCING - Dividend Restrictions and Structural Considerations Narrative (Details) $ in Billions	12 Months Ended
	Dec. 31, 2022 USD ($)
Variable Interest Entity [Line Items]
Undistributed retained earnings of subsidiaries	$ 4.9
Southern Company Gas
Variable Interest Entity [Line Items]
Retained earnings, unappropriated	$ 1.5
Southern Company Gas | Southern Company Gas Capital
Variable Interest Entity [Line Items]
Noncontrolling ownership percentage held by parent	100%

LEASES - Major Categories of Le

LEASES - Major Categories of Lease Obligations (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Lessee, Lease, Description [Line Items]
Lease obligations	$ 1,899	$ 1,969
Alabama Power
Lessee, Lease, Description [Line Items]
Lease obligations	81	124
Georgia Power
Lessee, Lease, Description [Line Items]
Lease obligations	1,240	1,291
Mississippi Power
Lessee, Lease, Description [Line Items]
Lease obligations	26	28
Southern Power
Lessee, Lease, Description [Line Items]
Lease obligations	542	526
Southern Company Gas
Lessee, Lease, Description [Line Items]
Lease obligations	60	70
Electric generating units(*)
Lessee, Lease, Description [Line Items]
Lease obligations	760	802
Electric generating units(*) | Alabama Power
Lessee, Lease, Description [Line Items]
Lease obligations	59	104
Electric generating units(*) | Georgia Power
Lessee, Lease, Description [Line Items]
Lease obligations	1,163	1,217
Electric generating units(*) | Mississippi Power
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Electric generating units(*) | Southern Power
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Electric generating units(*) | Southern Company Gas
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Real estate/land
Lessee, Lease, Description [Line Items]
Lease obligations	885	876
Real estate/land | Alabama Power
Lessee, Lease, Description [Line Items]
Lease obligations	4	3
Real estate/land | Georgia Power
Lessee, Lease, Description [Line Items]
Lease obligations	54	49
Real estate/land | Mississippi Power
Lessee, Lease, Description [Line Items]
Lease obligations	2	2
Real estate/land | Southern Power
Lessee, Lease, Description [Line Items]
Lease obligations	542	526
Real estate/land | Southern Company Gas
Lessee, Lease, Description [Line Items]
Lease obligations	36	45
Communication towers
Lessee, Lease, Description [Line Items]
Lease obligations	141	156
Communication towers | Alabama Power
Lessee, Lease, Description [Line Items]
Lease obligations	2	2
Communication towers | Georgia Power
Lessee, Lease, Description [Line Items]
Lease obligations	4	4
Communication towers | Mississippi Power
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Communication towers | Southern Power
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Communication towers | Southern Company Gas
Lessee, Lease, Description [Line Items]
Lease obligations	23	24
Railcars
Lessee, Lease, Description [Line Items]
Lease obligations	34	32
Railcars | Alabama Power
Lessee, Lease, Description [Line Items]
Lease obligations	12	10
Railcars | Georgia Power
Lessee, Lease, Description [Line Items]
Lease obligations	18	20
Railcars | Mississippi Power
Lessee, Lease, Description [Line Items]
Lease obligations	3	2
Railcars | Southern Power
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Railcars | Southern Company Gas
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Other
Lessee, Lease, Description [Line Items]
Lease obligations	79	103
Other | Alabama Power
Lessee, Lease, Description [Line Items]
Lease obligations	4	5
Other | Georgia Power
Lessee, Lease, Description [Line Items]
Lease obligations	1	1
Other | Mississippi Power
Lessee, Lease, Description [Line Items]
Lease obligations	21	24
Other | Southern Power
Lessee, Lease, Description [Line Items]
Lease obligations	0	0
Other | Southern Company Gas
Lessee, Lease, Description [Line Items]
Lease obligations	$ 1	$ 1

LEASES - Additional Information

LEASES - Additional Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 1,585	$ 1,754
Transfer of construction work in progress to lease receivables		210
Communication towers
Lessee, Lease, Description [Line Items]
Lessee, renewal period	20 years
Maximum | Real estate
Lessee, Lease, Description [Line Items]
Remaining terms	23 years
Maximum | Land
Lessee, Lease, Description [Line Items]
Lessee, lease term	44 years
Maximum | Communication towers
Lessee, Lease, Description [Line Items]
Lessee, lease term	10 years
Maximum | Fuel cells
Lessee, Lease, Description [Line Items]
Lessor, lease term, operating lease	11 years
Alabama Power
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 76	121
Alabama Power | Maximum | Electric generating units
Lessee, Lease, Description [Line Items]
Operating lease remaining lease term	17 years
Alabama Power | Minimum | Electric generating units
Lessee, Lease, Description [Line Items]
Operating lease remaining lease term	1 year
Georgia Power
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 1,002	1,155
Variable lease, payment	45	41	$ 39
Georgia Power | Purchased power, affiliates
Lessee, Lease, Description [Line Items]
Variable lease, payment	21	20	20
Mississippi Power
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 9	10
Transfer of construction work in progress to lease receivables		39	26
Sales-type lease, lease receivable		39	26
Mississippi Power | Maximum | Electric generating units
Lessee, Lease, Description [Line Items]
Lessor, sales-type lease, term of contract	16 years
Southern Power
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 542	$ 525
Lessor, sales-type lease, term of contract		20 years
Sales-type lease, lease receivable		$ 210
Loss on sales-type leases	1	40	$ 0
Net investment in sales-type lease, long-term portion	$ 154	161
Southern Power | Maximum | Electric generating units
Lessee, Lease, Description [Line Items]
Lessor, lease term, operating lease	24 years
Lessor, sales-type lease, term of contract	19 years
Southern Company Gas
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 60	70
Southern Company Gas | Maximum
Lessee, Lease, Description [Line Items]
Lessor, remaining term	20 years
Affiliate | Georgia Power | Electric generating units
Lessee, Lease, Description [Line Items]
Operating lease obligations	$ 461	$ 521
Traditional Electric Operating Companies | Maximum | Outdoor lighting
Lessee, Lease, Description [Line Items]
Lessor, lease term, operating lease	7 years

LEASES - Balance Sheet Amounts

LEASES - Balance Sheet Amounts Recorded for Operating and Financing Leases (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Operating Leases
Operating lease ROU assets, net	$ 1,531	$ 1,701
Operating lease obligations - current	197	250
Operating lease obligations - non-current	1,388	1,503
Total operating lease obligations	$ 1,585	$ 1,754
Finance Leases
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Plant in service, net of depreciation	Plant in service, net of depreciation
Finance lease ROU assets, net	$ 292	$ 197
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Finance lease obligations - current	$ 18	$ 16
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-Term Debt	Long-Term Debt
Finance lease obligations - non-current	$ 296	$ 199
Total finance lease obligations	314	215
Assets Subject to Power Purchase Agreement
Operating Leases
Total operating lease obligations	652	802
Alabama Power
Operating Leases
Operating lease ROU assets, net	$ 71	$ 108
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Operating lease obligations - current	$ 9	$ 54
Operating lease obligations - non-current	67	66
Total operating lease obligations	$ 76	$ 121
Finance Leases
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Plant in service, net of depreciation	Plant in service, net of depreciation
Finance lease ROU assets, net	$ 5	$ 4
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Finance lease obligations - current	$ 2	$ 1
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-Term Debt	Long-Term Debt
Finance lease obligations - non-current	$ 3	$ 3
Total finance lease obligations	5	4
Alabama Power | Assets Subject to Power Purchase Agreement
Operating Leases
Total operating lease obligations	59	104
Georgia Power
Operating Leases
Operating lease ROU assets, net	1,007	1,157
Operating lease obligations - current	151	156
Operating lease obligations - non-current	851	999
Total operating lease obligations	$ 1,002	$ 1,155
Finance Leases
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Plant in service, net of depreciation	Plant in service, net of depreciation
Finance lease ROU assets, net	$ 205	$ 104
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Finance lease obligations - current	$ 16	$ 10
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-Term Debt	Long-Term Debt
Finance lease obligations - non-current	$ 222	$ 126
Total finance lease obligations	238	136
Georgia Power | Assets Subject to Power Purchase Agreement
Operating Leases
Total operating lease obligations	$ 952	$ 1,110
Mississippi Power
Operating Leases
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Operating lease ROU assets, net	$ 9	$ 10
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Operating lease obligations - current	$ 4	$ 4
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Intangible liabilities included in other deferred credits and liabilities	Intangible liabilities included in other deferred credits and liabilities
Operating lease obligations - non-current	$ 5	$ 6
Total operating lease obligations	$ 9	$ 10
Finance Leases
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Plant in service, net of depreciation	Plant in service, net of depreciation
Finance lease ROU assets, net	$ 16	$ 17
Finance Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Finance lease obligations - current	$ 1	$ 1
Finance Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Long-Term Debt	Long-Term Debt
Finance lease obligations - non-current	$ 16	$ 17
Total finance lease obligations	17	18
Southern Power
Operating Leases
Operating lease ROU assets, net	$ 489	$ 479
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Operating lease obligations - current	$ 28	$ 28
Operating lease obligations - non-current	514	497
Total operating lease obligations	542	525
Finance Leases
Finance lease ROU assets, net	0	0
Finance lease obligations - current	0	0
Finance lease obligations - non-current	0	0
Total finance lease obligations	0	0
Southern Company Gas
Operating Leases
Operating lease ROU assets, net	$ 57	$ 70
Operating Lease, Liability, Current, Statement of Financial Position [Extensible Enumeration]	Other Liabilities, Current	Other Liabilities, Current
Operating lease obligations - current	$ 9	$ 11
Operating lease obligations - non-current	51	59
Total operating lease obligations	60	70
Finance Leases
Finance lease ROU assets, net	0	0
Finance lease obligations - current	0	0
Finance lease obligations - non-current	0	0
Total finance lease obligations	$ 0	$ 0

LEASES - Lease Costs (Details)

LEASES - Lease Costs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Lease cost
Operating lease cost	$ 297	$ 313	$ 309
Finance lease cost:
Amortization of ROU assets	23	21	26
Interest on lease obligations	13	11	11
Total finance lease cost	36	32	37
Short-term lease costs	64	48	39
Variable lease cost	125	96	91
Sublease income	(1)	1	0
Total lease cost	521	490	476
Assets Subject to Power Purchase Agreement
Lease cost
Operating lease cost	162	165	161
Alabama Power
Lease cost
Operating lease cost	59	58	55
Finance lease cost:
Amortization of ROU assets	1	1	1
Interest on lease obligations	0	0	0
Total finance lease cost	1	1	1
Short-term lease costs	44	15	11
Variable lease cost	13	4	4
Sublease income	0	0	(1)
Total lease cost	117	78	70
Alabama Power | Assets Subject to Power Purchase Agreement
Lease cost
Operating lease cost	48	47	43
Georgia Power
Lease cost
Operating lease cost	198	208	212
Finance lease cost:
Amortization of ROU assets	15	11	15
Interest on lease obligations	17	16	16
Total finance lease cost	32	27	31
Short-term lease costs	13	24	26
Variable lease cost	105	83	76
Sublease income	0	0	0
Total lease cost	348	342	345
Georgia Power | Assets Subject to Power Purchase Agreement
Lease cost
Operating lease cost	180	184	184
Mississippi Power
Lease cost
Operating lease cost	5	2	3
Finance lease cost:
Amortization of ROU assets	1	1	0
Interest on lease obligations	1	1	0
Total finance lease cost	2	2	0
Short-term lease costs	0	0	0
Variable lease cost	0	0	0
Sublease income	0	0	0
Total lease cost	7	4	3
Southern Power
Lease cost
Operating lease cost	32	33	29
Finance lease cost:
Amortization of ROU assets	0	0	0
Interest on lease obligations	0	0	0
Total finance lease cost	0	0	0
Short-term lease costs	0	0	0
Variable lease cost	5	5	7
Sublease income	0	0	0
Total lease cost	37	38	36
Southern Company Gas
Lease cost
Operating lease cost	15	19	19
Finance lease cost:
Amortization of ROU assets	0	0	0
Interest on lease obligations	0	0	0
Total finance lease cost	0	0	0
Short-term lease costs	0	0	0
Variable lease cost	0	0	0
Sublease income	0	0	0
Total lease cost	$ 15	$ 19	$ 19

LEASES - Other Information (Det

LEASES - Other Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 303	$ 308	$ 310
Operating cash flows from finance leases	11	9	9
Financing cash flows from finance leases	16	17	22
ROU assets obtained under operating leases	56	64	227
Reassessment of ROU assets under operating leases	16
ROU assets obtained under finance leases	$ 118	$ 3	10
Weighted-average remaining lease term in years:
Operating leases	17 years 3 months 18 days	15 years 10 months 24 days
Finance leases	17 years 4 months 24 days	18 years
Weighted-average discount rate:
Operating leases	4.51%	4.41%
Finance leases	4.87%	4.82%
Alabama Power
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 58	$ 58	55
Operating cash flows from finance leases	0	0	0
Financing cash flows from finance leases	1	1	1
ROU assets obtained under operating leases	10	3	63
Reassessment of ROU assets under operating leases	0
ROU assets obtained under finance leases	$ 2	$ 0	2
Weighted-average remaining lease term in years:
Operating leases	13 years	9 years 1 month 6 days
Finance leases	6 years 4 months 24 days	8 years 8 months 12 days
Weighted-average discount rate:
Operating leases	4.87%	4.37%
Finance leases	3%	3.09%
Georgia Power
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 206	$ 211	215
Operating cash flows from finance leases	20	17	18
Financing cash flows from finance leases	10	9	11
ROU assets obtained under operating leases	17	9	32
Reassessment of ROU assets under operating leases	0
ROU assets obtained under finance leases	$ 116	$ 0	0
Weighted-average remaining lease term in years:
Operating leases	8 years 1 month 6 days	8 years 8 months 12 days
Finance leases	11 years 9 months 18 days	8 years 6 months
Weighted-average discount rate:
Operating leases	4.52%	4.45%
Finance leases	8.06%	10.81%
Mississippi Power
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 5	$ 2	3
Operating cash flows from finance leases	1	1	0
Financing cash flows from finance leases	1	1	0
ROU assets obtained under operating leases	9	0	0
Reassessment of ROU assets under operating leases	0
ROU assets obtained under finance leases	$ 0	$ 0	0
Weighted-average remaining lease term in years:
Operating leases	4 years 8 months 12 days	6 years 1 month 6 days
Finance leases	12 years 10 months 24 days	13 years 10 months 24 days
Weighted-average discount rate:
Operating leases	3.49%	2.74%
Finance leases	2.74%	2.74%
Southern Power
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 30	$ 28	28
Operating cash flows from finance leases	0	0	0
Financing cash flows from finance leases	0	0	0
ROU assets obtained under operating leases	0	72	51
Reassessment of ROU assets under operating leases	16
ROU assets obtained under finance leases	$ 0	$ 0	0
Weighted-average remaining lease term in years:
Operating leases	34 years	32 years 9 months 18 days
Weighted-average discount rate:
Operating leases	4.86%	5.20%
Southern Company Gas
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 14	$ 19	18
Operating cash flows from finance leases	0	0	0
Financing cash flows from finance leases	0	0	0
ROU assets obtained under operating leases	3	7	4
Reassessment of ROU assets under operating leases	0
ROU assets obtained under finance leases	$ 0	$ 0	$ 0
Weighted-average remaining lease term in years:
Operating leases	11 years	10 years 6 months
Weighted-average discount rate:
Operating leases	3.79%	3.61%

LEASES - Maturities of Lease Li

LEASES - Maturities of Lease Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Operating leases:
2023	$ 248
2024	201
2025	181
2026	159
2027	143
Thereafter	1,497
Total	2,429
Less: Present value discount	844
Operating lease obligations	1,585	$ 1,754
Finance leases:
2023	33
2024	22
2025	26
2026	26
2027	26
Thereafter	345
Total	478
Less: Present value discount	164
Finance lease obligations	314	215
Alabama Power
Operating leases:
2023	12
2024	10
2025	9
2026	6
2027	5
Thereafter	64
Total	106
Less: Present value discount	30
Operating lease obligations	76	121
Finance leases:
2023	2
2024	1
2025	1
2026	1
2027	0
Thereafter	0
Total	5
Less: Present value discount	0
Finance lease obligations	5	4
Georgia Power
Operating leases:
2023	191
2024	165
2025	138
2026	135
2027	135
Thereafter	440
Total	1,204
Less: Present value discount	202
Operating lease obligations	1,002	1,155
Finance leases:
2023	35
2024	27
2025	35
2026	36
2027	36
Thereafter	187
Total	356
Less: Present value discount	118
Finance lease obligations	238	136
Mississippi Power
Operating leases:
2023	4
2024	2
2025	2
2026	1
2027	0
Thereafter	1
Total	10
Less: Present value discount	1
Operating lease obligations	9	10
Finance leases:
2023	2
2024	2
2025	2
2026	2
2027	2
Thereafter	10
Total	20
Less: Present value discount	3
Finance lease obligations	17	18
Southern Power
Operating leases:
2023	36
2024	28
2025	28
2026	28
2027	29
Thereafter	1,009
Total	1,158
Less: Present value discount	616
Operating lease obligations	542	525
Finance leases:
2023	0
2024	0
2025	0
2026	0
2027	0
Thereafter	0
Total	0
Less: Present value discount	0
Finance lease obligations	0	0
Southern Company Gas
Operating leases:
2023	11
2024	11
2025	11
2026	8
2027	3
Thereafter	31
Total	75
Less: Present value discount	15
Operating lease obligations	60	70
Finance leases:
2023	0
2024	0
2025	0
2026	0
2027	0
Thereafter	0
Total	0
Less: Present value discount	0
Finance lease obligations	$ 0	$ 0

LEASES - Lease Income (Details)

LEASES - Lease Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	$ 25	$ 15	$ 16
Lease income - operating leases	208	223	208
Variable lease income	417	429	419
Total lease income	650	$ 667	643
Operating lease, income, comprehensive income, extensible list, not disclosed, flag		Lease income - operating leases
Alabama Power
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	0	$ 0	0
Lease income - operating leases	77	82	45
Variable lease income	1	0	0
Total lease income	78	82	45
Georgia Power
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	0	0	0
Lease income - operating leases	32	42	58
Variable lease income	0	0	0
Total lease income	32	42	58
Mississippi Power
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	15	14	12
Lease income - operating leases	2	2	2
Variable lease income	0	0	0
Total lease income	17	16	14
Southern Power
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	10	1	0
Lease income - operating leases	85	85	87
Variable lease income	448	456	449
Total lease income	543	542	536
Southern Company Gas
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	0	0	0
Lease income - operating leases	36	35	35
Variable lease income	0	0	0
Total lease income	$ 36	$ 35	$ 35

LEASES - Undiscounted Cash Flow

LEASES - Undiscounted Cash Flows to be Received Under Tolling Arrangements Accounted for as Sales-type Leases (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]
2023	$ 39
2024	38
2025	37
2026	36
2027	35
Thereafter	364
Total undiscounted cash flows	549
Lease receivable	326
Difference between undiscounted cash flows and discounted cash flows	223
Other Property and Investments | Mississippi Power
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]
2023	24
2024	23
2025	22
2026	21
2027	20
Thereafter	164
Total undiscounted cash flows	274
Lease receivable	157
Difference between undiscounted cash flows and discounted cash flows	117
Other Current Assets and Net Investment in Sales-type Lease | Southern Power
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]
2023	15
2024	15
2025	15
2026	15
2027	15
Thereafter	200
Total undiscounted cash flows	275
Lease receivable	169
Difference between undiscounted cash flows and discounted cash flows	106
Other current assets | Southern Power
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]
Lease receivable	15	$ 12
Net investment in sales-type leases | Southern Power
Sales-type and Direct Financing Leases, Lease Receivable, Fiscal Year Maturity [Abstract]
Lease receivable	$ 154	$ 161

LEASES - Undiscounted Cash Fl_2

LEASES - Undiscounted Cash Flows to be Received Under PPAs Accounted for as Operating Leases (Details) $ in Millions	Dec. 31, 2022 USD ($)
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2023	$ 145
2024	114
2025	105
2026	104
2027	104
Thereafter	796
Total	1,368
Alabama Power
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2023	34
2024	6
2025	5
2026	3
2027	3
Thereafter	23
Total	74
Southern Power
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2023	88
2024	90
2025	74
2026	73
2027	74
Thereafter	166
Total	565
Southern Company Gas
Lessor, Operating Lease, Payments, Fiscal Year Maturity [Abstract]
2023	36
2024	34
2025	29
2026	29
2027	28
Thereafter	382
Total	$ 538

LEASES - Leveraged Leases (Narr

LEASES - Leveraged Leases (Narrative) (Details) $ in Millions	3 Months Ended	12 Months Ended
	Jun. 30, 2020 USD ($)	Dec. 31, 2022 USD ($) leveragedLease	Dec. 31, 2021 USD ($) project	Dec. 31, 2020 USD ($) project leveragedLease
Leveraged Lease [Line Items]
Number of leveraged leases | leveragedLease		1		4
Number of domestic projects subject to leveraged lease				2
Number of international projects subject to leveraged lease				2
Number of domestic projects subject to leveraged lease sold			1
Remaining lease term		9 years
Lease, impairment loss | $	$ 154	$ 0	$ 7	$ 206
Lease, impairment loss, after tax | $	$ 74

LEASES - Summary of the Compone

LEASES - Summary of the Components of Income from Leveraged Leases (Details) - Domestic and international leveraged leases - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Leveraged Lease [Line Items]
Pretax leveraged lease income (loss)	$ 17	$ (180)
Income tax benefit (expense)	(5)	98
Net leveraged lease income (loss)	$ 12	$ (82)

INCOME TAXES - Current and Defe

INCOME TAXES - Current and Deferred Income Tax Provisions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Federal —
Current	$ 10	$ 50	$ 199
Deferred	455	36	70
Total federal taxes	465	86	269
State —
Current	27	(25)	100
Deferred	303	206	24
Total state taxes	330	181	124
Income taxes	795	267	393
Alabama Power
Federal —
Current	54	104	198
Deferred	259	172	44
Total federal taxes	313	276	242
State —
Current	14	23	61
Deferred	96	73	34
Total state taxes	110	96	95
Income taxes	423	372	337
Georgia Power
Federal —
Current	38	311	365
Deferred	152	(449)	(224)
Total federal taxes	190	(138)	141
State —
Current	(21)	71	60
Deferred	201	(101)	(49)
Total state taxes	180	(30)	11
Income taxes	370	(168)	152
Mississippi Power
Federal —
Current	42	25	18
Deferred	(16)	(15)	(14)
Total federal taxes	26	10	4
State —
Current	0	0	0
Deferred	11	11	10
Total state taxes	11	11	10
Income taxes	37	21	14
Southern Power
Federal —
Current	(43)	(340)	(303)
Deferred	56	343	299
Total federal taxes	13	3	(4)
State —
Current	2	(16)	(4)
Deferred	5	0	11
Total state taxes	7	(16)	7
Income taxes	20	(13)	3
Southern Company Gas
Federal —
Current	122	85	82
Deferred	(3)	35	53
Total federal taxes	119	120	135
State —
Current	42	(68)	35
Deferred	19	223	3
Total state taxes	61	155	38
Income taxes	$ 180	$ 275	$ 173

INCOME TAXES - Narrative (Detai

INCOME TAXES - Narrative (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended		12 Months Ended
	Jul. 31, 2021	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Line Items]
Deferred income tax assets		$ 8,914	$ 8,914	$ 8,398	$ 8,914
ITC and PTC carryforwards
Income Tax Disclosure [Line Items]
Deferred income tax assets		1,750	1,750	1,685	1,750
Southern Power
Income Tax Disclosure [Line Items]
Deferred income tax assets		1,258	1,258	$ 1,124	1,258
Percentage reduction in tax basis of assets				50%
Southern Power | ITCs and other credits carryforward
Income Tax Disclosure [Line Items]
Reduction in income tax expense, investment tax credits				$ 49	289	$ 340
Southern Power | ITC and PTC carryforwards
Income Tax Disclosure [Line Items]
Deferred income tax assets		827	827	794	827
Southern Power | Production Tax Credit Carryforward
Income Tax Disclosure [Line Items]
Effective income tax rate reconciliation, tax credit, production, amount				27	16	15
Georgia Power
Income Tax Disclosure [Line Items]
Deferred income tax assets		4,019	4,019	3,844	4,019
State investment tax credit carryforward				434
Georgia Power | ITC and PTC carryforwards
Income Tax Disclosure [Line Items]
Deferred income tax assets		704	704	673	704
Mississippi Power
Income Tax Disclosure [Line Items]
Deferred income tax assets		393	393	399	393
Mississippi Power | ITC and PTC carryforwards
Income Tax Disclosure [Line Items]
Deferred income tax assets		0	0	0	0
Southern Company Gas
Income Tax Disclosure [Line Items]
Deferred income tax assets		328	328	301	328
Southern Company Gas | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Sequent
Income Tax Disclosure [Line Items]
Deferred tax expense, increase from change in appointment rate	$ 85	85	85	85
Southern Company Gas | ITC and PTC carryforwards
Income Tax Disclosure [Line Items]
Deferred income tax assets		0	0	0	0
State and Local Jurisdiction | Georgia Power
Income Tax Disclosure [Line Items]
Valuation allowance				98
State and Local Jurisdiction | Georgia Power | ITCs and other credits carryforward
Income Tax Disclosure [Line Items]
Reduction in income tax expense, investment tax credits				53	66	67
Deferred Charges Related To Income Taxes, Current | Other Noncurrent Assets | Southern Power | Unrealized Tax Credits
Income Tax Disclosure [Line Items]
Deferred income tax assets		$ 6	$ 6	17	$ 6	$ 5
Mississippi | State and Local Jurisdiction | Mississippi Power
Income Tax Disclosure [Line Items]
Operating loss carryforwards, valuation allowance				32
New York | State and Local Jurisdiction | Southern Power
Income Tax Disclosure [Line Items]
Operating loss carryforwards, valuation allowance				25
Oklahoma | State and Local Jurisdiction | Southern Power
Income Tax Disclosure [Line Items]
Operating loss carryforwards, valuation allowance				11
Florida | State and Local Jurisdiction | Southern Power
Income Tax Disclosure [Line Items]
Operating loss carryforwards, valuation allowance				$ 10

INCOME TAXES - Amortization of

INCOME TAXES - Amortization of Deferred Credits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Income Tax Disclosure [Line Items]
Amortization of deferred investment tax credits	$ 83	$ 84	$ 84
Southern Power
Income Tax Disclosure [Line Items]
Amortization of deferred investment tax credits	$ 58	$ 58	$ 59

INCOME TAXES - Reconciliation o

INCOME TAXES - Reconciliation of Federal Statutory Income Tax Rate (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Reconciliation of federal statutory income tax rate to effective income tax rate
Federal statutory rate	21%	21%	21%
State income tax, net of federal deduction	6.20%	5.50%	2.80%
Employee stock plans' dividend deduction	(0.50%)	(0.90%)	(0.70%)
Non-deductible book depreciation	0.60%	0.90%	0.70%
Flowback of excess deferred income taxes	(6.60%)	(11.70%)	(8.80%)
AFUDC-Equity	(1.10%)	(1.50%)	(0.80%)
Federal PTCs	0%	0%	0%
ITC amortization	(1.30%)	(2.20%)	(1.60%)
Noncontrolling interests	0.50%	0.80%	0%
Leveraged lease impairments and dispositions		(1.40%)	(1.60%)
Other	0%	(0.10%)	0.20%
Effective income tax (benefit) rate	18.80%	10.40%	11.20%
Alabama Power
Reconciliation of federal statutory income tax rate to effective income tax rate
Federal statutory rate	21%	21%	21%
State income tax, net of federal deduction	4.80%	4.60%	5%
Employee stock plans' dividend deduction	0%	0%	0%
Non-deductible book depreciation	0.50%	0.50%	0.60%
Flowback of excess deferred income taxes	(1.90%)	(2.60%)	(3.10%)
AFUDC-Equity	(0.80%)	(0.70%)	(0.60%)
Federal PTCs	0%	0%	0%
ITC amortization	(0.10%)	(0.10%)	(0.10%)
Noncontrolling interests	0%	0%	0%
Leveraged lease impairments and dispositions		0%	0%
Other	0.30%	0.20%	(0.30%)
Effective income tax (benefit) rate	23.80%	22.90%	22.50%
Georgia Power
Reconciliation of federal statutory income tax rate to effective income tax rate
Federal statutory rate	21%	21%	21%
State income tax, net of federal deduction	6.50%	(5.70%)	0.50%
Employee stock plans' dividend deduction	0%	0%	0%
Non-deductible book depreciation	0.60%	3.10%	0.80%
Flowback of excess deferred income taxes	(9.60%)	(49.90%)	(12.00%)
AFUDC-Equity	(1.50%)	(6.40%)	(1.10%)
Federal PTCs	0%	0%	0%
ITC amortization	(0.10%)	(0.40%)	(0.10%)
Noncontrolling interests	0%	0%	0%
Leveraged lease impairments and dispositions		0%	0%
Other	0%	(1.90%)	(0.30%)
Effective income tax (benefit) rate	16.90%	(40.20%)	8.80%
Mississippi Power
Reconciliation of federal statutory income tax rate to effective income tax rate
Federal statutory rate	21%	21%	21%
State income tax, net of federal deduction	4.40%	4.90%	4.80%
Employee stock plans' dividend deduction	0%	0%	0%
Non-deductible book depreciation	0.30%	0.40%	0.50%
Flowback of excess deferred income taxes	(7.80%)	(15.20%)	(18.50%)
AFUDC-Equity	0%	0%	(0.10%)
Federal PTCs	0%	0%	0%
ITC amortization	0%	0%	(0.10%)
Noncontrolling interests	0%	0%	0%
Leveraged lease impairments and dispositions		0%	0%
Other	0.30%	0.60%	0.90%
Effective income tax (benefit) rate	18.20%	11.70%	8.50%
Southern Power
Reconciliation of federal statutory income tax rate to effective income tax rate
Federal statutory rate	21%	21%	21%
State income tax, net of federal deduction	1.90%	(8.00%)	2.70%
Employee stock plans' dividend deduction	0%	0%	0%
Non-deductible book depreciation	0%	0%	0%
Flowback of excess deferred income taxes	0%	0%	0%
AFUDC-Equity	0%	0%	0%
Federal PTCs	(6.60%)	(4.60%)	(2.50%)
ITC amortization	(17.20%)	(29.70%)	(22.10%)
Noncontrolling interests	8.40%	13.40%	3.10%
Leveraged lease impairments and dispositions		0%	0%
Other	(0.10%)	(0.40%)	(0.90%)
Effective income tax (benefit) rate	7.40%	(8.30%)	1.30%
Southern Company Gas
Reconciliation of federal statutory income tax rate to effective income tax rate
Federal statutory rate	21%	21%	21%
State income tax, net of federal deduction	6.40%	15.10%	4%
Employee stock plans' dividend deduction	0%	0%	0%
Non-deductible book depreciation	0%	0%	0%
Flowback of excess deferred income taxes	(2.50%)	(2.80%)	(2.70%)
AFUDC-Equity	0%	0%	0%
Federal PTCs	0%	0%	0%
ITC amortization	(0.10%)	(0.10%)	(0.10%)
Noncontrolling interests	0%	0%	0%
Leveraged lease impairments and dispositions		0%	0%
Other	(0.90%)	0.60%	0.50%
Effective income tax (benefit) rate	23.90%	33.80%	22.70%

INCOME TAXES - Deferred Tax Ass

INCOME TAXES - Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Deferred tax liabilities —
Deferred income tax liabilities	$ 18,066	$ 17,451
Deferred tax assets —
Deferred income tax assets	8,398	8,914
Valuation allowance	(257)	(207)
Net deferred income tax assets	8,141	8,707
Net deferred income taxes liabilities	9,925	8,744
Accumulated deferred income taxes – assets	(111)	(118)
Accumulated deferred income taxes – liabilities	10,036	8,862
Net deferred income taxes liabilities	9,925	8,744
Accelerated depreciation
Deferred tax liabilities —
Deferred income tax liabilities	9,443	9,300
Property basis differences
Deferred tax liabilities —
Deferred income tax liabilities	2,350	2,301
Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	888	820
Deferred tax assets —
Deferred income tax assets	890	1,035
AROs
Deferred tax liabilities —
Deferred income tax liabilities	876	868
Under recovered fuel and natural gas costs
Deferred tax liabilities —
Deferred income tax liabilities	805	315
AROs
Deferred tax liabilities —
Deferred income tax liabilities	2,006	2,232
Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	677	825
Remaining book value of retired assets
Deferred tax liabilities —
Deferred income tax liabilities	400	271
Premium on reacquired debt
Deferred tax liabilities —
Deferred income tax liabilities	66	72
Other
Deferred tax liabilities —
Deferred income tax liabilities	555	368
ITC and PTC carryforwards
Deferred tax assets —
Deferred income tax assets	1,685	1,750
Estimated loss on plants under construction
Deferred tax assets —
Deferred income tax assets	888	825
Other state deferred tax attributes
Deferred tax assets —
Deferred income tax assets	388	361
Federal effect of net state deferred tax assets/liabilities
Deferred tax liabilities —
Deferred income tax liabilities		0
Deferred tax assets —
Deferred income tax assets	365	305
Other property basis differences
Deferred tax assets —
Deferred income tax assets	207	231
State effect of federal deferred taxes
Deferred tax assets —
Deferred income tax assets	136	135
Other partnership basis differences
Deferred tax assets —
Deferred income tax assets	111	160
Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)
Deferred tax assets —
Deferred income tax assets	137	268
Long-term debt fair value adjustment
Deferred tax assets —
Deferred income tax assets	85	91
Other comprehensive losses
Deferred tax assets —
Deferred income tax assets	72	92
Other
Deferred tax assets —
Deferred income tax assets	552	561
Leveraged lease basis differences
Deferred tax liabilities —
Deferred income tax liabilities		61
Storm damage reserves
Deferred tax liabilities —
Deferred income tax liabilities		18
AROs
Deferred tax assets —
Deferred income tax assets	2,882	3,100
Alabama Power
Deferred tax liabilities —
Deferred income tax liabilities	6,024	5,737
Deferred tax assets —
Deferred income tax assets	2,043	2,164
Valuation allowance	0	0
Net deferred income tax assets	2,043	2,164
Net deferred income taxes liabilities	3,981	3,573
Accumulated deferred income taxes – assets	0	0
Accumulated deferred income taxes – liabilities	3,981	3,573
Net deferred income taxes liabilities	3,981	3,573
Alabama Power | Accelerated depreciation
Deferred tax liabilities —
Deferred income tax liabilities	2,564	2,541
Alabama Power | Property basis differences
Deferred tax liabilities —
Deferred income tax liabilities	1,303	1,182
Alabama Power | Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	284	268
Deferred tax assets —
Deferred income tax assets	198	225
Alabama Power | AROs
Deferred tax liabilities —
Deferred income tax liabilities	499	329
Alabama Power | Under recovered fuel and natural gas costs
Deferred tax liabilities —
Deferred income tax liabilities	185	47
Alabama Power | AROs
Deferred tax liabilities —
Deferred income tax liabilities	679	863
Alabama Power | Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	180	205
Alabama Power | Remaining book value of retired assets
Deferred tax liabilities —
Deferred income tax liabilities	142	145
Alabama Power | Premium on reacquired debt
Deferred tax liabilities —
Deferred income tax liabilities	9	10
Alabama Power | Other
Deferred tax liabilities —
Deferred income tax liabilities	179	147
Alabama Power | ITC and PTC carryforwards
Deferred tax assets —
Deferred income tax assets	12	12
Alabama Power | Estimated loss on plants under construction
Deferred tax assets —
Deferred income tax assets	0	0
Alabama Power | Other state deferred tax attributes
Deferred tax assets —
Deferred income tax assets	0	0
Alabama Power | Federal effect of net state deferred tax assets/liabilities
Deferred tax liabilities —
Deferred income tax liabilities		0
Deferred tax assets —
Deferred income tax assets	175	165
Alabama Power | Other property basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Alabama Power | State effect of federal deferred taxes
Deferred tax assets —
Deferred income tax assets	136	135
Alabama Power | Other partnership basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Alabama Power | Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)
Deferred tax assets —
Deferred income tax assets	127	237
Alabama Power | Long-term debt fair value adjustment
Deferred tax assets —
Deferred income tax assets	0	0
Alabama Power | Other comprehensive losses
Deferred tax assets —
Deferred income tax assets	4	5
Alabama Power | Other
Deferred tax assets —
Deferred income tax assets	213	193
Alabama Power | Leveraged lease basis differences
Deferred tax liabilities —
Deferred income tax liabilities		0
Alabama Power | Storm damage reserves
Deferred tax liabilities —
Deferred income tax liabilities		0
Alabama Power | AROs
Deferred tax assets —
Deferred income tax assets	1,178	1,192
Georgia Power
Deferred tax liabilities —
Deferred income tax liabilities	7,426	6,965
Deferred tax assets —
Deferred income tax assets	3,844	4,019
Valuation allowance	(125)	(73)
Net deferred income tax assets	3,719	3,946
Net deferred income taxes liabilities	3,707	3,019
Accumulated deferred income taxes – assets	0	0
Accumulated deferred income taxes – liabilities	3,707	3,019
Net deferred income taxes liabilities	3,707	3,019
Georgia Power | Accelerated depreciation
Deferred tax liabilities —
Deferred income tax liabilities	3,447	3,340
Georgia Power | Property basis differences
Deferred tax liabilities —
Deferred income tax liabilities	693	781
Georgia Power | Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	412	382
Deferred tax assets —
Deferred income tax assets	304	342
Georgia Power | AROs
Deferred tax liabilities —
Deferred income tax liabilities	324	494
Georgia Power | Under recovered fuel and natural gas costs
Deferred tax liabilities —
Deferred income tax liabilities	548	109
Georgia Power | AROs
Deferred tax liabilities —
Deferred income tax liabilities	1,285	1,325
Georgia Power | Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	226	256
Georgia Power | Remaining book value of retired assets
Deferred tax liabilities —
Deferred income tax liabilities	253	121
Georgia Power | Premium on reacquired debt
Deferred tax liabilities —
Deferred income tax liabilities	57	62
Georgia Power | Other
Deferred tax liabilities —
Deferred income tax liabilities	181	77
Georgia Power | ITC and PTC carryforwards
Deferred tax assets —
Deferred income tax assets	673	704
Georgia Power | Estimated loss on plants under construction
Deferred tax assets —
Deferred income tax assets	888	825
Georgia Power | Other state deferred tax attributes
Deferred tax assets —
Deferred income tax assets	12	11
Georgia Power | Federal effect of net state deferred tax assets/liabilities
Deferred tax liabilities —
Deferred income tax liabilities		0
Deferred tax assets —
Deferred income tax assets	88	41
Georgia Power | Other property basis differences
Deferred tax assets —
Deferred income tax assets	79	90
Georgia Power | State effect of federal deferred taxes
Deferred tax assets —
Deferred income tax assets	0	0
Georgia Power | Other partnership basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Georgia Power | Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)
Deferred tax assets —
Deferred income tax assets	0	19
Georgia Power | Long-term debt fair value adjustment
Deferred tax assets —
Deferred income tax assets	0	0
Georgia Power | Other comprehensive losses
Deferred tax assets —
Deferred income tax assets	5	15
Georgia Power | Other
Deferred tax assets —
Deferred income tax assets	186	153
Georgia Power | Leveraged lease basis differences
Deferred tax liabilities —
Deferred income tax liabilities		0
Georgia Power | Storm damage reserves
Deferred tax liabilities —
Deferred income tax liabilities		18
Georgia Power | AROs
Deferred tax assets —
Deferred income tax assets	1,609	1,819
Mississippi Power
Deferred tax liabilities —
Deferred income tax liabilities	717	698
Deferred tax assets —
Deferred income tax assets	399	393
Valuation allowance	(41)	(41)
Net deferred income tax assets	358	352
Net deferred income taxes liabilities	359	346
Accumulated deferred income taxes – assets	(107)	(118)
Accumulated deferred income taxes – liabilities	466	464
Net deferred income taxes liabilities	359	346
Mississippi Power | Accelerated depreciation
Deferred tax liabilities —
Deferred income tax liabilities	338	330
Mississippi Power | Property basis differences
Deferred tax liabilities —
Deferred income tax liabilities	179	169
Mississippi Power | Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	43	41
Deferred tax assets —
Deferred income tax assets	47	57
Mississippi Power | AROs
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Mississippi Power | Under recovered fuel and natural gas costs
Deferred tax liabilities —
Deferred income tax liabilities	40	15
Mississippi Power | AROs
Deferred tax liabilities —
Deferred income tax liabilities	42	44
Mississippi Power | Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	30	38
Mississippi Power | Remaining book value of retired assets
Deferred tax liabilities —
Deferred income tax liabilities	5	5
Mississippi Power | Premium on reacquired debt
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Mississippi Power | Other
Deferred tax liabilities —
Deferred income tax liabilities	40	34
Mississippi Power | ITC and PTC carryforwards
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power | Estimated loss on plants under construction
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power | Other state deferred tax attributes
Deferred tax assets —
Deferred income tax assets	239	246
Mississippi Power | Federal effect of net state deferred tax assets/liabilities
Deferred tax liabilities —
Deferred income tax liabilities		22
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power | Other property basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power | State effect of federal deferred taxes
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power | Other partnership basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power | Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)
Deferred tax assets —
Deferred income tax assets	9	12
Mississippi Power | Long-term debt fair value adjustment
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power | Other comprehensive losses
Deferred tax assets —
Deferred income tax assets	0	0
Mississippi Power | Other
Deferred tax assets —
Deferred income tax assets	62	34
Mississippi Power | Leveraged lease basis differences
Deferred tax liabilities —
Deferred income tax liabilities		0
Mississippi Power | Storm damage reserves
Deferred tax liabilities —
Deferred income tax liabilities		0
Mississippi Power | AROs
Deferred tax assets —
Deferred income tax assets	42	44
Southern Power
Deferred tax liabilities —
Deferred income tax liabilities	1,376	1,446
Deferred tax assets —
Deferred income tax assets	1,124	1,258
Valuation allowance	(27)	(27)
Net deferred income tax assets	1,097	1,231
Net deferred income taxes liabilities	279	215
Accumulated deferred income taxes – assets	0	0
Accumulated deferred income taxes – liabilities	279	215
Net deferred income taxes liabilities	279	215
Southern Power | Accelerated depreciation
Deferred tax liabilities —
Deferred income tax liabilities	1,351	1,421
Southern Power | Property basis differences
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power | Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	11	11
Deferred tax assets —
Deferred income tax assets	9	7
Southern Power | AROs
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power | Under recovered fuel and natural gas costs
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power | AROs
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power | Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power | Remaining book value of retired assets
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power | Premium on reacquired debt
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Power | Other
Deferred tax liabilities —
Deferred income tax liabilities	14	14
Southern Power | ITC and PTC carryforwards
Deferred tax assets —
Deferred income tax assets	794	827
Southern Power | Estimated loss on plants under construction
Deferred tax assets —
Deferred income tax assets	0	0
Southern Power | Other state deferred tax attributes
Deferred tax assets —
Deferred income tax assets	51	52
Southern Power | Federal effect of net state deferred tax assets/liabilities
Deferred tax liabilities —
Deferred income tax liabilities		0
Deferred tax assets —
Deferred income tax assets	28	27
Southern Power | Other property basis differences
Deferred tax assets —
Deferred income tax assets	109	121
Southern Power | State effect of federal deferred taxes
Deferred tax assets —
Deferred income tax assets	0	0
Southern Power | Other partnership basis differences
Deferred tax assets —
Deferred income tax assets	111	160
Southern Power | Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)
Deferred tax assets —
Deferred income tax assets	0	0
Southern Power | Long-term debt fair value adjustment
Deferred tax assets —
Deferred income tax assets	0	0
Southern Power | Other comprehensive losses
Deferred tax assets —
Deferred income tax assets	5	11
Southern Power | Other
Deferred tax assets —
Deferred income tax assets	17	53
Southern Power | Leveraged lease basis differences
Deferred tax liabilities —
Deferred income tax liabilities		0
Southern Power | Storm damage reserves
Deferred tax liabilities —
Deferred income tax liabilities		0
Southern Power | AROs
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas
Deferred tax liabilities —
Deferred income tax liabilities	1,852	1,874
Deferred tax assets —
Deferred income tax assets	301	328
Valuation allowance	(9)	(9)
Net deferred income tax assets	292	319
Net deferred income taxes liabilities	1,560	1,555
Accumulated deferred income taxes – assets	0	0
Accumulated deferred income taxes – liabilities	1,560	1,555
Net deferred income taxes liabilities	1,560	1,555
Southern Company Gas | Accelerated depreciation
Deferred tax liabilities —
Deferred income tax liabilities	1,505	1,428
Southern Company Gas | Property basis differences
Deferred tax liabilities —
Deferred income tax liabilities	150	148
Southern Company Gas | Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	68	57
Deferred tax assets —
Deferred income tax assets	89	77
Southern Company Gas | AROs
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Company Gas | Under recovered fuel and natural gas costs
Deferred tax liabilities —
Deferred income tax liabilities	32	144
Southern Company Gas | AROs
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Company Gas | Employee benefit obligations
Deferred tax liabilities —
Deferred income tax liabilities	15	15
Southern Company Gas | Remaining book value of retired assets
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Company Gas | Premium on reacquired debt
Deferred tax liabilities —
Deferred income tax liabilities	0	0
Southern Company Gas | Other
Deferred tax liabilities —
Deferred income tax liabilities	82	82
Southern Company Gas | ITC and PTC carryforwards
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas | Estimated loss on plants under construction
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas | Other state deferred tax attributes
Deferred tax assets —
Deferred income tax assets	7	5
Southern Company Gas | Federal effect of net state deferred tax assets/liabilities
Deferred tax liabilities —
Deferred income tax liabilities		0
Deferred tax assets —
Deferred income tax assets	92	93
Southern Company Gas | Other property basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas | State effect of federal deferred taxes
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas | Other partnership basis differences
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas | Regulatory liability associated with the Tax Reform Legislation (not subject to normalization)
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas | Long-term debt fair value adjustment
Deferred tax assets —
Deferred income tax assets	85	91
Southern Company Gas | Other comprehensive losses
Deferred tax assets —
Deferred income tax assets	0	0
Southern Company Gas | Other
Deferred tax assets —
Deferred income tax assets	28	62
Southern Company Gas | Leveraged lease basis differences
Deferred tax liabilities —
Deferred income tax liabilities		0
Southern Company Gas | Storm damage reserves
Deferred tax liabilities —
Deferred income tax liabilities		0
Southern Company Gas | AROs
Deferred tax assets —
Deferred income tax assets	$ 0	$ 0

INCOME TAXES - Federal ITC_PTC

INCOME TAXES - Federal ITC/PTC Carryforwards (Details) - ITC and PTC carryforwards $ in Millions	Dec. 31, 2022 USD ($)
Operating Loss Carryforwards [Line Items]
Federal ITC/PTC carryforwards	$ 1,148
Alabama Power
Operating Loss Carryforwards [Line Items]
Federal ITC/PTC carryforwards	12
Georgia Power
Operating Loss Carryforwards [Line Items]
Federal ITC/PTC carryforwards	135
Southern Power
Operating Loss Carryforwards [Line Items]
Federal ITC/PTC carryforwards	$ 794

INCOME TAXES - NOL Carryforward

INCOME TAXES - NOL Carryforwards (Details) $ in Millions	Dec. 31, 2022 USD ($)
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	$ 298
Mississippi Power | Mississippi
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	189
Southern Power
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	40
Southern Power | Oklahoma
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	27
Southern Power | Florida
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	10
Southern Power | Other states
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	3
Other Subsidiaries | Other states
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	21
Other Subsidiaries | Georgia
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	23
Other Subsidiaries | New York
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	11
Other Subsidiaries | New York City
Operating Loss Carryforwards [Line Items]
Approximate Net State Income Tax Benefit of NOL Carryforwards	$ 14

INCOME TAXES - Changes in Unrec

INCOME TAXES - Changes in Unrecognized Tax Benefits (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Changes in unrecognized tax benefits [Roll Forward]
Beginning balance	$ 47	$ 44	$ 0
Tax positions changes – increase from prior periods	33	3	44
Ending balance	80	47	44
Southern Company Gas
Changes in unrecognized tax benefits [Roll Forward]
Beginning balance	0	0	0
Tax positions changes – increase from prior periods	32	0	0
Ending balance	$ 32	$ 0	$ 0

RETIREMENT BENEFITS - Narrative

RETIREMENT BENEFITS - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Plan asset amortization period	5 years
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 61,000,000	$ 60,000,000
Expected future employer contributions, next fiscal year	0
Actuarial losses	$ (3,908,000,000)	$ (393,000,000)
Change in discount rate	21,600%	0.28%
Pension plans | Qualified pension plan
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 0
Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	73,000,000	$ 43,000,000
Expected future employer contributions, next fiscal year	0
Actuarial losses	$ (365,000,000)	$ (54,000,000)

RETIREMENT BENEFITS - Actuarial

RETIREMENT BENEFITS - Actuarial Assumptions (Details)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	3.09%	2.81%	3.41%
Expected long-term return on plan assets	8.25%	8.25%	8.25%
Annual salary increase, net periodic costs	4.80%	4.80%	4.73%
Pension plans | Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	2.55%	2.13%	2.99%
Pension plans | Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	3.34%	3.18%	3.66%
Pension plans | Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.25%	3.09%
Annual salary increase	4.80%	4.80%
Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	2.90%	2.56%	3.24%
Expected long-term return on plan assets	7.21%	7.09%	7.25%
Annual salary increase, net periodic costs	4.80%	4.80%	4.73%
Other postretirement benefit plans | Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	2.32%	1.84%	2.80%
Other postretirement benefit plans | Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	3.26%	3.07%	3.57%
Other postretirement benefit plans | Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.18%	2.90%
Annual salary increase	4.80%	4.80%
Alabama Power | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	3.12%	2.85%	3.44%
Expected long-term return on plan assets	8.25%	8.25%	8.25%
Annual salary increase, net periodic costs	4.80%	4.80%	4.73%
Alabama Power | Pension plans | Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	2.58%	2.17%	3.01%
Alabama Power | Pension plans | Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	3.36%	3.23%	3.69%
Alabama Power | Pension plans | Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.26%	3.12%
Annual salary increase	4.80%	4.80%
Alabama Power | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	2.95%	2.63%	3.28%
Expected long-term return on plan assets	7.54%	7.18%	7.36%
Annual salary increase, net periodic costs	4.80%	4.80%	4.73%
Alabama Power | Other postretirement benefit plans | Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	2.38%	1.91%	2.84%
Alabama Power | Other postretirement benefit plans | Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	3.30%	3.13%	3.61%
Alabama Power | Other postretirement benefit plans | Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.20%	2.95%
Annual salary increase	4.80%	4.80%
Georgia Power | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	3.07%	2.79%	3.40%
Expected long-term return on plan assets	8.25%	8.25%	8.25%
Annual salary increase, net periodic costs	4.80%	4.80%	4.73%
Georgia Power | Pension plans | Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	2.51%	2.09%	2.96%
Georgia Power | Pension plans | Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	3.37%	3.21%	3.67%
Georgia Power | Pension plans | Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.25%	3.07%
Annual salary increase	4.80%	4.80%
Georgia Power | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	2.87%	2.52%	3.22%
Expected long-term return on plan assets	6.88%	6.84%	7.05%
Annual salary increase, net periodic costs	4.80%	4.80%	4.73%
Georgia Power | Other postretirement benefit plans | Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	2.30%	1.82%	2.79%
Georgia Power | Other postretirement benefit plans | Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	3.27%	3.08%	3.57%
Georgia Power | Other postretirement benefit plans | Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.17%	2.87%
Annual salary increase	4.80%	4.80%
Mississippi Power | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	3.07%	2.80%	3.41%
Expected long-term return on plan assets	8.25%	8.25%	8.25%
Annual salary increase, net periodic costs	4.80%	4.80%	4.73%
Mississippi Power | Pension plans | Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	2.54%	2.12%	2.99%
Mississippi Power | Pension plans | Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	3.35%	3.20%	3.67%
Mississippi Power | Pension plans | Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.25%	3.07%
Annual salary increase	4.80%	4.80%
Mississippi Power | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	2.88%	2.53%	3.22%
Expected long-term return on plan assets	7.22%	6.98%	7.07%
Annual salary increase, net periodic costs	4.80%	4.80%	4.73%
Mississippi Power | Other postretirement benefit plans | Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	2.27%	1.78%	2.76%
Mississippi Power | Other postretirement benefit plans | Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	3.26%	3.06%	3.57%
Mississippi Power | Other postretirement benefit plans | Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.17%	2.88%
Annual salary increase	4.80%	4.80%
Southern Power | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	3.21%	2.99%	3.52%
Expected long-term return on plan assets	8.25%	8.25%	8.25%
Annual salary increase, net periodic costs	4.80%	4.80%	4.73%
Southern Power | Pension plans | Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	2.79%	2.46%	3.18%
Southern Power | Pension plans | Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	3.36%	3.22%	3.70%
Southern Power | Pension plans | Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.31%	3.21%
Annual salary increase	4.80%	4.80%
Southern Power | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	3.07%	2.78%	3.39%
Expected long-term return on plan assets	0%	0%	0%
Annual salary increase, net periodic costs	4.80%	4.80%	4.73%
Southern Power | Other postretirement benefit plans | Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	2.55%	2.12%	2.97%
Southern Power | Other postretirement benefit plans | Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	3.25%	3.05%	3.57%
Southern Power | Other postretirement benefit plans | Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.24%	3.07%
Annual salary increase	4.80%	4.80%
Southern Company Gas | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	3.04%	2.75%	3.39%
Expected long-term return on plan assets	8.25%	8.25%	8.25%
Annual salary increase, net periodic costs	4.80%	4.80%	4.73%
Southern Company Gas | Pension plans | Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	2.53%	2.10%	2.99%
Southern Company Gas | Pension plans | Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	3.21%	2.97%	3.53%
Southern Company Gas | Pension plans | Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.24%	3.04%
Annual salary increase	4.80%	4.80%
Southern Company Gas | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	2.82%	2.46%	3.19%
Expected long-term return on plan assets	6.08%	6.54%	6.69%
Annual salary increase, net periodic costs	4.80%	4.80%	4.73%
Southern Company Gas | Other postretirement benefit plans | Discount rate – interest costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	2.17%	1.64%	2.71%
Southern Company Gas | Other postretirement benefit plans | Discount rate – service costs
Defined Benefit Plan Disclosure [Line Items]
Discount rate, net periodic benefit costs	3.22%	3.01%	3.52%
Southern Company Gas | Other postretirement benefit plans | Employee benefit obligations
Defined Benefit Plan Disclosure [Line Items]
Discount rate – benefit obligations	5.16%	2.82%
Annual salary increase	4.80%	4.80%

RETIREMENT BENEFITS - Schedule

RETIREMENT BENEFITS - Schedule of Health Care Cost Trend Rates (Details)	Dec. 31, 2022
Pre-65
Defined Benefit Plan Disclosure [Line Items]
Initial Cost Trend Rate	6.60%
Ultimate Cost Trend Rate	4.50%
Post-65 medical
Defined Benefit Plan Disclosure [Line Items]
Initial Cost Trend Rate	5.50%
Ultimate Cost Trend Rate	4.50%
Post-65 prescription
Defined Benefit Plan Disclosure [Line Items]
Initial Cost Trend Rate	7.50%
Ultimate Cost Trend Rate	4.50%

RETIREMENT BENEFITS - Accumulat

RETIREMENT BENEFITS - Accumulated Benefit Obligation (Details) - Pension plans - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Total accumulated benefit obligation for the pension plans	$ 11,422	$ 14,687
Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Total accumulated benefit obligation for the pension plans	2,601	3,362
Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Total accumulated benefit obligation for the pension plans	3,534	4,562
Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Total accumulated benefit obligation for the pension plans	520	672
Southern Power
Defined Benefit Plan Disclosure [Line Items]
Total accumulated benefit obligation for the pension plans	135	178
Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Total accumulated benefit obligation for the pension plans	$ 801	$ 1,030

RETIREMENT BENEFITS - Changes i

RETIREMENT BENEFITS - Changes in Projected Benefit Obligations and Fair Value of Plan Assets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension plans
Change in benefit obligation
Benefit obligation at beginning of year	$ 16,382,000,000	$ 16,646,000,000
Service cost	412,000,000	434,000,000	$ 376,000,000
Interest cost	408,000,000	346,000,000	432,000,000
Benefits paid	(692,000,000)	(651,000,000)
Actuarial gain	(3,908,000,000)	(393,000,000)
Balance at end of year	12,602,000,000	16,382,000,000	16,646,000,000
Change in plan assets
Fair value of plan assets at beginning of year	17,225,000,000	15,367,000,000
Actual return on plan assets	(2,376,000,000)	2,449,000,000
Employer contributions	61,000,000	60,000,000
Benefits paid	(692,000,000)	(651,000,000)
Fair value of plan assets at end of year	14,218,000,000	17,225,000,000	15,367,000,000
Accrued asset	1,616,000,000	843,000,000
Other postretirement benefit plans
Change in benefit obligation
Benefit obligation at beginning of year	1,849,000,000	1,948,000,000
Service cost	23,000,000	24,000,000	22,000,000
Interest cost	42,000,000	35,000,000	54,000,000
Benefits paid	(109,000,000)	(105,000,000)
Actuarial gain	(365,000,000)	(54,000,000)
Retiree drug subsidy	1,000,000	1,000,000
Balance at end of year	1,441,000,000	1,849,000,000	1,948,000,000
Change in plan assets
Fair value of plan assets at beginning of year	1,251,000,000	1,158,000,000
Actual return on plan assets	(218,000,000)	154,000,000
Employer contributions	73,000,000	43,000,000
Benefits paid	(108,000,000)	(104,000,000)
Fair value of plan assets at end of year	998,000,000	1,251,000,000	1,158,000,000
Accrued asset	(443,000,000)	(598,000,000)
Alabama Power | Pension plans
Change in benefit obligation
Benefit obligation at beginning of year	3,806,000,000	3,854,000,000
Service cost	99,000,000	102,000,000	89,000,000
Interest cost	96,000,000	82,000,000	100,000,000
Benefits paid	(144,000,000)	(137,000,000)
Actuarial gain	(951,000,000)	(95,000,000)
Balance at end of year	2,906,000,000	3,806,000,000	3,854,000,000
Change in plan assets
Fair value of plan assets at beginning of year	4,141,000,000	3,684,000,000
Actual return on plan assets	(579,000,000)	586,000,000
Employer contributions	9,000,000	8,000,000
Benefits paid	(144,000,000)	(137,000,000)
Fair value of plan assets at end of year	3,427,000,000	4,141,000,000	3,684,000,000
Accrued asset	521,000,000	335,000,000
Alabama Power | Other postretirement benefit plans
Change in benefit obligation
Benefit obligation at beginning of year	440,000,000	463,000,000
Service cost	6,000,000	6,000,000	6,000,000
Interest cost	10,000,000	9,000,000	13,000,000
Benefits paid	(23,000,000)	(22,000,000)
Actuarial gain	(89,000,000)	(16,000,000)
Retiree drug subsidy	0	0
Balance at end of year	344,000,000	440,000,000	463,000,000
Change in plan assets
Fair value of plan assets at beginning of year	489,000,000	458,000,000
Actual return on plan assets	(98,000,000)	55,000,000
Employer contributions	4,000,000	(2,000,000)
Benefits paid	(23,000,000)	(22,000,000)
Fair value of plan assets at end of year	372,000,000	489,000,000	458,000,000
Accrued asset	28,000,000	49,000,000
Georgia Power | Pension plans
Change in benefit obligation
Benefit obligation at beginning of year	5,012,000,000	5,127,000,000
Service cost	103,000,000	112,000,000	96,000,000
Interest cost	123,000,000	104,000,000	133,000,000
Benefits paid	(226,000,000)	(210,000,000)
Actuarial gain	(1,161,000,000)	(121,000,000)
Balance at end of year	3,851,000,000	5,012,000,000	5,127,000,000
Change in plan assets
Fair value of plan assets at beginning of year	5,415,000,000	4,844,000,000
Actual return on plan assets	(753,000,000)	781,000,000
Employer contributions	20,000,000	0
Benefits paid	(226,000,000)	(210,000,000)
Fair value of plan assets at end of year	4,456,000,000	5,415,000,000	4,844,000,000
Accrued asset	605,000,000	403,000,000
Georgia Power | Other postretirement benefit plans
Change in benefit obligation
Benefit obligation at beginning of year	656,000,000	699,000,000
Service cost	6,000,000	7,000,000	6,000,000
Interest cost	15,000,000	12,000,000	20,000,000
Benefits paid	(38,000,000)	(36,000,000)
Actuarial gain	(125,000,000)	(26,000,000)
Retiree drug subsidy	0	0
Balance at end of year	514,000,000	656,000,000	699,000,000
Change in plan assets
Fair value of plan assets at beginning of year	450,000,000	427,000,000
Actual return on plan assets	(71,000,000)	55,000,000
Employer contributions	27,000,000	4,000,000
Benefits paid	(38,000,000)	(36,000,000)
Fair value of plan assets at end of year	368,000,000	450,000,000	427,000,000
Accrued asset	(146,000,000)	(206,000,000)
Mississippi Power | Pension plans
Change in benefit obligation
Benefit obligation at beginning of year	743,000,000	754,000,000
Service cost	17,000,000	18,000,000	15,000,000
Interest cost	18,000,000	16,000,000	20,000,000
Benefits paid	(30,000,000)	(28,000,000)
Actuarial gain	(179,000,000)	(17,000,000)
Balance at end of year	569,000,000	743,000,000	754,000,000
Change in plan assets
Fair value of plan assets at beginning of year	786,000,000	701,000,000
Actual return on plan assets	(110,000,000)	111,000,000
Employer contributions	3,000,000	2,000,000
Benefits paid	(30,000,000)	(28,000,000)
Fair value of plan assets at end of year	649,000,000	786,000,000	701,000,000
Accrued asset	80,000,000	43,000,000
Mississippi Power | Other postretirement benefit plans
Change in benefit obligation
Benefit obligation at beginning of year	76,000,000	81,000,000
Service cost	1,000,000	1,000,000	1,000,000
Interest cost	2,000,000	1,000,000	2,000,000
Benefits paid	(4,000,000)	(5,000,000)
Actuarial gain	(16,000,000)	(2,000,000)
Retiree drug subsidy	0	0
Balance at end of year	59,000,000	76,000,000	81,000,000
Change in plan assets
Fair value of plan assets at beginning of year	29,000,000	27,000,000
Actual return on plan assets	(4,000,000)	4,000,000
Employer contributions	3,000,000	3,000,000
Benefits paid	(4,000,000)	(5,000,000)
Fair value of plan assets at end of year	24,000,000	29,000,000	27,000,000
Accrued asset	(35,000,000)	(47,000,000)
Southern Power | Pension plans
Change in benefit obligation
Benefit obligation at beginning of year	222,000,000	217,000,000
Service cost	9,000,000	10,000,000	8,000,000
Interest cost	6,000,000	5,000,000	6,000,000
Benefits paid	(5,000,000)	(4,000,000)
Actuarial gain	(69,000,000)	(6,000,000)
Balance at end of year	163,000,000	222,000,000	217,000,000
Change in plan assets
Fair value of plan assets at beginning of year	213,000,000	186,000,000
Actual return on plan assets	(31,000,000)	30,000,000
Employer contributions	1,000,000	1,000,000
Benefits paid	(5,000,000)	(4,000,000)
Fair value of plan assets at end of year	178,000,000	213,000,000	186,000,000
Accrued asset	15,000,000	(9,000,000)
Southern Power | Other postretirement benefit plans
Change in benefit obligation
Benefit obligation at beginning of year	11,000,000	12,000,000
Service cost	0	0	1,000,000
Interest cost	0	0	0
Benefits paid	(1,000,000)	0
Actuarial gain	(1,000,000)	(1,000,000)
Retiree drug subsidy	0	0
Balance at end of year	9,000,000	11,000,000	12,000,000
Change in plan assets
Fair value of plan assets at beginning of year	0	0
Actual return on plan assets	0	0
Employer contributions	1,000,000	0
Benefits paid	(1,000,000)	0
Fair value of plan assets at end of year	0	0	0
Accrued asset	(9,000,000)	(11,000,000)
Southern Company Gas | Pension plans
Change in benefit obligation
Benefit obligation at beginning of year	1,134,000,000	1,189,000,000
Service cost	34,000,000	37,000,000	33,000,000
Interest cost	28,000,000	24,000,000	31,000,000
Benefits paid	(75,000,000)	(73,000,000)
Actuarial gain	(253,000,000)	(43,000,000)
Balance at end of year	868,000,000	1,134,000,000	1,189,000,000
Change in plan assets
Fair value of plan assets at beginning of year	1,241,000,000	1,123,000,000
Actual return on plan assets	(167,000,000)	181,000,000
Employer contributions	3,000,000	10,000,000
Benefits paid	(75,000,000)	(73,000,000)
Fair value of plan assets at end of year	1,002,000,000	1,241,000,000	1,123,000,000
Accrued asset	134,000,000	107,000,000
Southern Company Gas | Other postretirement benefit plans
Change in benefit obligation
Benefit obligation at beginning of year	237,000,000	248,000,000
Service cost	1,000,000	2,000,000	2,000,000
Interest cost	5,000,000	4,000,000	7,000,000
Benefits paid	(18,000,000)	(18,000,000)
Actuarial gain	(46,000,000)	1,000,000
Retiree drug subsidy	0	0
Balance at end of year	179,000,000	237,000,000	248,000,000
Change in plan assets
Fair value of plan assets at beginning of year	143,000,000	128,000,000
Actual return on plan assets	(25,000,000)	18,000,000
Employer contributions	13,000,000	15,000,000
Benefits paid	(18,000,000)	(18,000,000)
Fair value of plan assets at end of year	113,000,000	143,000,000	$ 128,000,000
Accrued asset	(66,000,000)	$ (94,000,000)
Qualified pension plan | Pension plans
Change in benefit obligation
Balance at end of year	11,928,000,000
Change in plan assets
Employer contributions	0
Qualified pension plan | Alabama Power | Pension plans
Change in benefit obligation
Balance at end of year	2,799,000,000
Qualified pension plan | Georgia Power | Pension plans
Change in benefit obligation
Balance at end of year	3,717,000,000
Qualified pension plan | Mississippi Power | Pension plans
Change in benefit obligation
Balance at end of year	540,000,000
Qualified pension plan | Southern Power | Pension plans
Change in benefit obligation
Balance at end of year	140,000,000
Qualified pension plan | Southern Company Gas | Pension plans
Change in benefit obligation
Balance at end of year	819,000,000
Non-qualified pension plan | Pension plans
Change in benefit obligation
Balance at end of year	674,000,000
Non-qualified pension plan | Alabama Power | Pension plans
Change in benefit obligation
Balance at end of year	107,000,000
Non-qualified pension plan | Georgia Power | Pension plans
Change in benefit obligation
Balance at end of year	134,000,000
Non-qualified pension plan | Mississippi Power | Pension plans
Change in benefit obligation
Balance at end of year	28,000,000
Non-qualified pension plan | Southern Power | Pension plans
Change in benefit obligation
Balance at end of year	23,000,000
Non-qualified pension plan | Southern Company Gas | Pension plans
Change in benefit obligation
Balance at end of year	$ 49,000,000

RETIREMENT BENEFITS - Amounts R

RETIREMENT BENEFITS - Amounts Recognized in Balance Sheets and Amounts in AOCI (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Other regulatory assets, deferred	$ 5,918	$ 5,577
Other current liabilities	(965)	(872)
Employee benefit obligations	(1,238)	(1,550)
Other regulatory liabilities, deferred	(733)	(485)
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension costs(a)	2,290	1,657
Other regulatory assets, deferred	2,455	2,920
Other current liabilities	(56)	(55)
Employee benefit obligations	(618)	(759)
Other regulatory liabilities, deferred	(85)	(119)
AOCI	24	100
Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	0	0
Other regulatory assets, deferred	34	97
Other current liabilities	(6)	(5)
Employee benefit obligations	(437)	(593)
Other regulatory liabilities, deferred	(170)	(171)
AOCI	(4)	0
Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	657	513
Other regulatory assets, deferred	2,107	1,807
Other current liabilities	(91)	(125)
Employee benefit obligations	(145)	(171)
Other regulatory liabilities, deferred	(315)	(210)
Alabama Power | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension costs(a)	629	464
Other regulatory assets, deferred	679	809
Other current liabilities	(10)	(9)
Employee benefit obligations	(98)	(120)
Other regulatory liabilities, deferred	0	0
AOCI	0	0
Alabama Power | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	28	49
Other regulatory assets, deferred	0	0
Other current liabilities	0	0
Employee benefit obligations	0	0
Other regulatory liabilities, deferred	(21)	(62)
AOCI	0	0
Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Other regulatory assets, deferred	2,522	1,964
Other current liabilities	(286)	(254)
Employee benefit obligations	(318)	(402)
Georgia Power | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension costs(a)	738	563
Other regulatory assets, deferred	887	971
Other current liabilities	(12)	(12)
Employee benefit obligations	(121)	(148)
Other regulatory liabilities, deferred	0	0
AOCI	0	0
Georgia Power | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	0	0
Other regulatory assets, deferred	19	30
Other current liabilities	0	0
Employee benefit obligations	(146)	(206)
Other regulatory liabilities, deferred	(58)	(40)
AOCI	0	0
Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension costs(a)	109	79
Other regulatory assets, deferred	249	317
Other current liabilities	(85)	(65)
Employee benefit obligations	(69)	(88)
Other regulatory liabilities, deferred	(96)	(64)
Mississippi Power | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension costs(a)	108	78
Other regulatory assets, deferred	123	146
Other current liabilities	(2)	(2)
Employee benefit obligations	(26)	(33)
Other regulatory liabilities, deferred	0	0
AOCI	0	0
Mississippi Power | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	0	0
Other regulatory assets, deferred	0	2
Other current liabilities	0	0
Employee benefit obligations	(35)	(47)
Other regulatory liabilities, deferred	(9)	(1)
AOCI	0	0
Southern Power
Defined Benefit Plan Disclosure [Line Items]
Other current liabilities	(111)	(140)
Southern Power | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension costs(a)	37	20
Other regulatory assets, deferred	0	0
Other current liabilities	(2)	(2)
Employee benefit obligations	(20)	(27)
Other regulatory liabilities, deferred	0	0
AOCI	11	35
Southern Power | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	0	0
Other regulatory assets, deferred	0	0
Other current liabilities	(1)	0
Employee benefit obligations	(8)	(11)
Other regulatory liabilities, deferred	0	0
AOCI	0	2
Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Other regulatory assets, deferred	497	689
Other current liabilities	(254)	(214)
Employee benefit obligations	(120)	(176)
Southern Company Gas | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension costs(a)	183	175
Other regulatory assets, deferred	111	91
Other current liabilities	(3)	(2)
Employee benefit obligations	(42)	(66)
Other regulatory liabilities, deferred	0	0
AOCI	(75)	(45)
Regulatory asset	190	210
Southern Company Gas | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Prepaid pension and other postretirement benefit costs	0	0
Other regulatory assets, deferred	0	0
Other current liabilities	0	0
Employee benefit obligations	(66)	(94)
Other regulatory liabilities, deferred	(58)	(34)
AOCI	(2)	(5)
Regulatory asset	$ 32	$ 40

RETIREMENT BENEFITS - Component

RETIREMENT BENEFITS - Components of Accumulated OCI and Changes in Regulatory Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	$ 32,276	$ 32,234	$ 31,759
Total other comprehensive income (loss)	71	158	(75)
Ending balance	34,532	32,276	32,234
Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(76)
Total other comprehensive income (loss)	58
Ending balance	(18)	(76)
Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	(2)	(2)
Net loss	26	102
Total AOCI	24	100
Pension plans | Regulatory Assets
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	10	11
Net loss	2,361	2,790
Regulatory amortization	0	0
Regulatory asset	2,371	2,801
Pension plans | Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	100	245
Reclassification adjustments	6
Total other comprehensive income (loss)	(76)	(145)
Ending balance	24	100	245
Pension plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	2,801	4,621
Reclassification adjustments	(247)	(297)
Total other comprehensive income (loss)	(430)	(1,820)
Ending balance	2,371	2,801	4,621
Pension plans | Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	82	128
Reclassification adjustments	6	(17)
Pension plans | Net gain | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	183	1,523
Reclassification adjustments	(246)	(296)
Pension plans | Change in prior service costs | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(1)	(1)
Pension plans | Amortization of regulatory assets | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	1	1
Net loss	(5)	(1)
Total AOCI	(4)	0
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(1)	3
Other postretirement benefit plans | Regulatory Assets
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	14	13
Net loss	(150)	(87)
Regulatory amortization	0	0
Regulatory liabilities	(136)	(74)
Other postretirement benefit plans | Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	0	8
Total other comprehensive income (loss)	(4)	(8)
Ending balance	(4)	0	8
Other postretirement benefit plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(74)	51
Reclassification adjustments	2	(5)
Total other comprehensive income (loss)	(62)	(125)
Ending balance	(136)	(74)	51
Other postretirement benefit plans | Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	(3)	(11)
Other postretirement benefit plans | Net gain | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	64	120
Reclassification adjustments	1	(6)
Other postretirement benefit plans | Change in prior service costs | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	1	1
Other postretirement benefit plans | Amortization of regulatory assets | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Alabama Power
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	10,713	9,810	8,955
Total other comprehensive income (loss)	4	6	4
Ending balance	11,687	10,713	9,810
Alabama Power | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Total AOCI	0	0
Alabama Power | Pension plans | Regulatory Assets
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	4	5
Net loss	675	804
Regulatory amortization	0	0
Regulatory asset	679	809
Alabama Power | Pension plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	809	1,286
Reclassification adjustments	(63)	(83)
Total other comprehensive income (loss)	(130)	(477)
Ending balance	679	809	1,286
Alabama Power | Pension plans | Net gain | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	67	394
Reclassification adjustments	(62)	(82)
Alabama Power | Pension plans | Change in prior service costs | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(1)	(1)
Alabama Power | Pension plans | Amortization of regulatory assets | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Alabama Power | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Total AOCI	0	0
Alabama Power | Other postretirement benefit plans | Regulatory Assets
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	4	3
Net loss	(25)	(65)
Regulatory amortization	0	0
Regulatory liabilities	(21)	(62)
Alabama Power | Other postretirement benefit plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(62)	(21)
Reclassification adjustments	0	0
Total other comprehensive income (loss)	41	(41)
Ending balance	(21)	(62)	(21)
Alabama Power | Other postretirement benefit plans | Net gain | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	(41)	41
Reclassification adjustments	0	0
Alabama Power | Other postretirement benefit plans | Change in prior service costs | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Alabama Power | Other postretirement benefit plans | Amortization of regulatory assets | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Georgia Power
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	17,234	16,501	15,065
Total other comprehensive income (loss)	28	6	4
Ending balance	18,858	17,234	16,501
Georgia Power | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Total AOCI	0	0
Georgia Power | Pension plans | Regulatory Assets
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	7	8
Net loss	880	963
Regulatory amortization	0	0
Regulatory asset	887	971
Georgia Power | Pension plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	971	1,598
Reclassification adjustments	(75)	(100)
Total other comprehensive income (loss)	(84)	(627)
Ending balance	887	971	1,598
Georgia Power | Pension plans | Net gain | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	9	527
Reclassification adjustments	(74)	(99)
Georgia Power | Pension plans | Change in prior service costs | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(1)	(1)
Georgia Power | Pension plans | Amortization of regulatory assets | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Georgia Power | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Total AOCI	0	0
Georgia Power | Other postretirement benefit plans | Regulatory Assets
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	6	5
Net loss	(45)	(15)
Regulatory amortization	0	0
Regulatory liabilities	(39)	(10)
Georgia Power | Other postretirement benefit plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(10)	47
Reclassification adjustments	(2)	(2)
Total other comprehensive income (loss)	(29)	(57)
Ending balance	(39)	(10)	47
Georgia Power | Other postretirement benefit plans | Net gain | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	27	55
Reclassification adjustments	(2)	(3)
Georgia Power | Other postretirement benefit plans | Change in prior service costs | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	1
Georgia Power | Other postretirement benefit plans | Amortization of regulatory assets | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Mississippi Power
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	1,867	1,742	1,652
Total other comprehensive income (loss)	0	1	1
Ending balance	1,931	1,867	1,742
Mississippi Power | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Total AOCI	0	0
Mississippi Power | Pension plans | Regulatory Assets
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	1	1
Net loss	122	145
Regulatory amortization	0	0
Regulatory asset	123	146
Mississippi Power | Pension plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	146	235
Reclassification adjustments	(11)	(15)
Total other comprehensive income (loss)	(23)	(89)
Ending balance	123	146	235
Mississippi Power | Pension plans | Net gain | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	12	74
Reclassification adjustments	(11)	(15)
Mississippi Power | Pension plans | Change in prior service costs | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Mississippi Power | Pension plans | Amortization of regulatory assets | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Mississippi Power | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Total AOCI	0	0
Mississippi Power | Other postretirement benefit plans | Regulatory Assets
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	1	1
Net loss	(10)	0
Regulatory amortization	0	0
Regulatory asset		1
Regulatory liabilities	(9)
Mississippi Power | Other postretirement benefit plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	1	5
Reclassification adjustments	0	0
Total other comprehensive income (loss)	(10)	(4)
Ending balance	(9)	1	5
Mississippi Power | Other postretirement benefit plans | Net gain | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	10	4
Reclassification adjustments	0	0
Mississippi Power | Other postretirement benefit plans | Change in prior service costs | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Mississippi Power | Other postretirement benefit plans | Amortization of regulatory assets | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Southern Power
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	6,598	6,631	6,622
Total other comprehensive income (loss)	10	40	(42)
Ending balance	6,916	6,598	6,631
Southern Power | Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(29)
Total other comprehensive income (loss)	20
Ending balance	(9)	(29)
Southern Power | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	0	0
Net loss	11	35
Total AOCI	11	35
Southern Power | Pension plans | Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	35	60
Reclassification adjustments	(2)
Total other comprehensive income (loss)	(24)	(25)
Ending balance	11	35	60
Southern Power | Pension plans | Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	22	22
Reclassification adjustments	(2)	(3)
Southern Power | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	0	0
Net loss	0	2
Total AOCI	0	2
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Southern Power | Other postretirement benefit plans | Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	2	3
Total other comprehensive income (loss)	(2)	(1)
Ending balance	0	2	3
Southern Power | Other postretirement benefit plans | Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	(2)	(1)
Southern Company Gas
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	9,916	9,767	9,506
Total other comprehensive income (loss)	7	46	(29)
Ending balance	10,397	9,916	9,767
Southern Company Gas | Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	38
Total other comprehensive income (loss)	18
Ending balance	56	38
Southern Company Gas | Pension plans
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	(3)	(3)
Net loss	(72)	(42)
Total AOCI	(75)	(45)
Regulatory asset	190	210
Southern Company Gas | Pension plans | Regulatory Assets
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	(9)	(11)
Net loss	66	38
Regulatory amortization	54	64
Regulatory asset	111	91
Southern Company Gas | Pension plans | Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(45)	1
Reclassification adjustments	0
Total other comprehensive income (loss)	(30)	(46)
Ending balance	(75)	(45)	1
Southern Company Gas | Pension plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	91	205
Reclassification adjustments	(7)	(17)
Total other comprehensive income (loss)	20	(114)
Ending balance	111	91	205
Southern Company Gas | Pension plans | Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	30	47
Reclassification adjustments	0	1
Southern Company Gas | Pension plans | Net gain | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	(27)	97
Reclassification adjustments	1	(9)
Southern Company Gas | Pension plans | Change in prior service costs | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	2	2
Southern Company Gas | Pension plans | Amortization of regulatory assets | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	(10)	(10)
Southern Company Gas | Other postretirement benefit plans
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	0	1
Net loss	(2)	(6)
Total AOCI	(2)	(5)
Regulatory asset	32	40
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	3	(5)
Southern Company Gas | Other postretirement benefit plans | Regulatory Assets
Defined Benefit Plan Disclosure [Line Items]
Prior service cost	1	1
Net loss	(64)	(51)
Regulatory amortization	5	16
Regulatory liabilities	(58)	(34)
Southern Company Gas | Other postretirement benefit plans | Pension and Other Postretirement Benefit Plans
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(5)	0
Total other comprehensive income (loss)	3	(5)
Ending balance	(2)	(5)	0
Southern Company Gas | Other postretirement benefit plans | Pension and Other Postretirement Benefit Plans | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance	(34)	(23)
Reclassification adjustments	(11)	(9)
Total other comprehensive income (loss)	(24)	(11)
Ending balance	(58)	(34)	$ (23)
Southern Company Gas | Other postretirement benefit plans | Net gain
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	0	0
Southern Company Gas | Other postretirement benefit plans | Net gain | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Net gain	13	2
Reclassification adjustments	0	0
Southern Company Gas | Other postretirement benefit plans | Change in prior service costs | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	0	0
Southern Company Gas | Other postretirement benefit plans | Amortization of regulatory assets | Regulatory Assets
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Reclassification adjustments	$ (11)	$ (9)

RETIREMENT BENEFITS - Compone_2

RETIREMENT BENEFITS - Components of Net Periodic Benefit Cost and Estimated Future Benefit Payments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Pension plans
Components of net periodic
Service cost	$ 412	$ 434	$ 376
Interest cost	408	346	432
Expected return on plan assets	(1,265)	(1,191)	(1,100)
Recognized net loss	240	314	269
Net amortization	0	1	1
Prior service cost	0	0	0
Total change	(205)	(96)	(22)
Benefit payments:
2023	734
2024	735
2025	760
2026	784
2027	806
2028 to 2032	4,262
Other postretirement benefit plans
Components of net periodic
Service cost	23	24	22
Interest cost	42	35	54
Expected return on plan assets	(80)	(76)	(72)
Prior service cost	(1)	2	1
Total change	(16)	(15)	5
Benefit payments:
2023	115
2024	110
2025	114
2026	113
2027	113
2028 to 2032	551
Alabama Power | Pension plans
Components of net periodic
Service cost	99	102	89
Interest cost	96	82	100
Expected return on plan assets	(306)	(287)	(264)
Recognized net loss	62	82	71
Net amortization	1	1	1
Prior service cost	0	0	0
Total change	(48)	(20)	(3)
Benefit payments:
2023	155
2024	160
2025	167
2026	173
2027	178
2028 to 2032	952
Alabama Power | Other postretirement benefit plans
Components of net periodic
Service cost	6	6	6
Interest cost	10	9	13
Expected return on plan assets	(32)	(30)	(29)
Prior service cost	0	0	0
Total change	(16)	(15)	(10)
Benefit payments:
2023	25
2024	24
2025	26
2026	26
2027	26
2028 to 2032	130
Georgia Power | Pension plans
Components of net periodic
Service cost	103	112	96
Interest cost	123	104	133
Expected return on plan assets	(399)	(375)	(347)
Recognized net loss	75	100	86
Net amortization	1	1	1
Prior service cost	0	0	0
Total change	(97)	(58)	(31)
Benefit payments:
2023	230
2024	236
2025	243
2026	248
2027	252
2028 to 2032	1,304
Georgia Power | Other postretirement benefit plans
Components of net periodic
Service cost	6	7	6
Interest cost	15	12	20
Expected return on plan assets	(28)	(26)	(26)
Prior service cost	2	2	2
Total change	(5)	(5)	2
Benefit payments:
2023	41
2024	39
2025	41
2026	41
2027	41
2028 to 2032	199
Mississippi Power | Pension plans
Components of net periodic
Service cost	17	18	15
Interest cost	18	16	20
Expected return on plan assets	(57)	(55)	(51)
Recognized net loss	11	15	13
Net amortization	0	0	0
Prior service cost	0	0	0
Total change	(11)	(6)	(3)
Benefit payments:
2023	32
2024	33
2025	34
2026	35
2027	36
2028 to 2032	192
Mississippi Power | Other postretirement benefit plans
Components of net periodic
Service cost	1	1	1
Interest cost	2	1	2
Expected return on plan assets	(2)	(1)	(1)
Prior service cost	0	0	0
Total change	1	1	2
Benefit payments:
2023	5
2024	5
2025	5
2026	5
2027	5
2028 to 2032	22
Southern Power | Pension plans
Components of net periodic
Service cost	9	10	8
Interest cost	6	5	6
Expected return on plan assets	(15)	(14)	(13)
Recognized net loss	2	3	2
Net amortization	0	0	0
Prior service cost	0	0	0
Total change	2	4	3
Benefit payments:
2023	6
2024	7
2025	7
2026	7
2027	8
2028 to 2032	43
Southern Power | Other postretirement benefit plans
Components of net periodic
Service cost	0	0	1
Interest cost	0	0	0
Expected return on plan assets	1	1	0
Prior service cost	0	0	0
Total change	1	1	1
Benefit payments:
2023	1
2024	1
2025	1
2026	1
2027	1
2028 to 2032	1
Southern Company Gas | Pension plans
Components of net periodic
Service cost	34	37	33
Interest cost	28	24	31
Expected return on plan assets	(91)	(86)	(75)
Recognized net loss	8	13	6
Net amortization	15	15	15
Prior service cost	(3)	(3)	(3)
Total change	(9)	0	7
Benefit payments:
2023	83
2024	57
2025	58
2026	60
2027	61
2028 to 2032	323
Southern Company Gas | Other postretirement benefit plans
Components of net periodic
Service cost	1	2	2
Interest cost	5	4	7
Expected return on plan assets	(9)	(10)	(10)
Prior service cost	6	6	6
Total change	3	$ 2	$ 5
Benefit payments:
2023	18
2024	17
2025	17
2026	16
2027	16
2028 to 2032	$ 68

RETIREMENT BENEFITS - Fair Valu

RETIREMENT BENEFITS - Fair Values of Pension Plan and Other Postretirement Benefit Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Assets:
Target Allocation	100%
Actual Allocation	100%
Pension plans
Assets:
Plan assets	$ 14,197	$ 17,225
Target Allocation		100%
Actual Allocation		100%
Derivatives	(4)
Defined Benefit Plan, Plan Assets, Amount, Excluding Cash, Investment Income And Pending Investment Sales Receivables, And Pending Investment Purchase Payables	$ 14,193
Pension plans | Equity
Assets:
Target Allocation	45%	51%
Actual Allocation	43%	53%
Pension plans | Domestic equity
Assets:
Plan assets	$ 2,769	$ 4,421
Pension plans | International equity
Assets:
Plan assets	$ 3,256	$ 4,145
Pension plans | Fixed income
Assets:
Target Allocation	30%	23%
Actual Allocation	28%	22%
Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 1,469	$ 1,209
Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	29	10
Pension plans | Corporate bonds
Assets:
Plan assets	1,494	1,752
Pension plans | Pooled funds
Assets:
Plan assets	607	771
Pension plans | Cash equivalents and other
Assets:
Plan assets	406	412
Pension plans | Real estate investments
Assets:
Plan assets	$ 2,263	$ 2,744
Target Allocation	13%	14%
Actual Allocation	15%	15%
Pension plans | Special situations
Assets:
Plan assets	$ 187	$ 171
Target Allocation	3%	3%
Actual Allocation	2%	1%
Pension plans | Private equity
Assets:
Plan assets	$ 1,717	$ 1,590
Target Allocation	9%	9%
Actual Allocation	12%	9%
Other postretirement benefit plans
Assets:
Plan assets	$ 998	$ 1,249
Target Allocation	100%	100%
Actual Allocation	100%	100%
Other postretirement benefit plans | Equity
Assets:
Target Allocation	61%	64%
Actual Allocation	59%	66%
Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	$ 159	$ 235
Other postretirement benefit plans | International equity
Assets:
Plan assets	$ 137	$ 172
Other postretirement benefit plans | Fixed income
Assets:
Target Allocation	30%	27%
Actual Allocation	28%	25%
Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 43	$ 37
Other postretirement benefit plans | Mortgage- and asset-backed securities
Assets:
Plan assets	1
Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	40	50
Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	79	90
Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	19	14
Other postretirement benefit plans | Trust-owned life insurance
Assets:
Plan assets	406	530
Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	$ 62	$ 74
Target Allocation	5%	5%
Actual Allocation	7%	6%
Other postretirement benefit plans | Special situations
Assets:
Plan assets	$ 6	$ 5
Target Allocation	1%	1%
Actual Allocation	1%	0%
Other postretirement benefit plans | Private equity
Assets:
Plan assets	$ 46	$ 42
Target Allocation	3%	3%
Actual Allocation	5%	3%
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans
Assets:
Plan assets	$ 5,019	$ 6,946
Derivatives	(4)
Defined Benefit Plan, Plan Assets, Amount, Excluding Cash, Investment Income And Pending Investment Sales Receivables, And Pending Investment Purchase Payables	5,015
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Domestic equity
Assets:
Plan assets	2,078	3,095
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | International equity
Assets:
Plan assets	2,166	2,740
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Cash equivalents and other
Assets:
Plan assets	399	405
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Real estate investments
Assets:
Plan assets	376	706
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Special situations
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private equity
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans
Assets:
Plan assets	173	230
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	85	123
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | International equity
Assets:
Plan assets	58	73
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	19	14
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Trust-owned life insurance
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	11	20
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Special situations
Assets:
Plan assets	0	0
Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	0	0
Significant Other Observable Inputs (Level 2) | Pension plans
Assets:
Plan assets	5,387	6,477
Derivatives	0
Defined Benefit Plan, Plan Assets, Amount, Excluding Cash, Investment Income And Pending Investment Sales Receivables, And Pending Investment Purchase Payables	5,387
Significant Other Observable Inputs (Level 2) | Pension plans | Domestic equity
Assets:
Plan assets	691	1,326
Significant Other Observable Inputs (Level 2) | Pension plans | International equity
Assets:
Plan assets	1,090	1,402
Significant Other Observable Inputs (Level 2) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	1,469	1,209
Significant Other Observable Inputs (Level 2) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	29	10
Significant Other Observable Inputs (Level 2) | Pension plans | Corporate bonds
Assets:
Plan assets	1,494	1,752
Significant Other Observable Inputs (Level 2) | Pension plans | Pooled funds
Assets:
Plan assets	607	771
Significant Other Observable Inputs (Level 2) | Pension plans | Cash equivalents and other
Assets:
Plan assets	7	7
Significant Other Observable Inputs (Level 2) | Pension plans | Real estate investments
Assets:
Plan assets	0	0
Significant Other Observable Inputs (Level 2) | Pension plans | Special situations
Assets:
Plan assets	0	0
Significant Other Observable Inputs (Level 2) | Pension plans | Private equity
Assets:
Plan assets	0	0
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans
Assets:
Plan assets	722	918
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	74	112
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | International equity
Assets:
Plan assets	79	99
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	43	37
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Mortgage- and asset-backed securities
Assets:
Plan assets	1
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	40	50
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	79	90
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	0	0
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Trust-owned life insurance
Assets:
Plan assets	406	530
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	0	0
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Special situations
Assets:
Plan assets	0	0
Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) | Pension plans
Assets:
Plan assets	0	3
Significant Unobservable Inputs (Level 3) | Pension plans | Domestic equity
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) | Pension plans | International equity
Assets:
Plan assets	0	3
Significant Unobservable Inputs (Level 3) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) | Pension plans | Real estate investments
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) | Pension plans | Special situations
Assets:
Plan assets	0	0
Significant Unobservable Inputs (Level 3) | Pension plans | Private equity
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Pension plans
Assets:
Plan assets	3,791	3,799
Derivatives	0
Defined Benefit Plan, Plan Assets, Amount, Excluding Cash, Investment Income And Pending Investment Sales Receivables, And Pending Investment Purchase Payables	3,791
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Domestic equity
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | International equity
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Real estate investments
Assets:
Plan assets	1,887	2,038
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Special situations
Assets:
Plan assets	187	171
Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private equity
Assets:
Plan assets	1,717	1,590
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans
Assets:
Plan assets	103	101
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | International equity
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Trust-owned life insurance
Assets:
Plan assets	0	0
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	51	54
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Special situations
Assets:
Plan assets	6	5
Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	$ 46	42
Alabama Power
Assets:
Target Allocation	100%
Actual Allocation	100%
Alabama Power | Pension plans
Assets:
Plan assets	$ 3,422	$ 4,141
Target Allocation	100%	100%
Actual Allocation	100%	100%
Derivatives	$ (1)
Defined Benefit Plan, Plan Assets, Amount, Excluding Cash, Investment Income And Pending Investment Sales Receivables, And Pending Investment Purchase Payables	$ 3,421
Alabama Power | Pension plans | Equity
Assets:
Target Allocation	45%	51%
Actual Allocation	43%	53%
Alabama Power | Pension plans | Domestic equity
Assets:
Plan assets	$ 667	$ 1,062
Alabama Power | Pension plans | International equity
Assets:
Plan assets	$ 785	$ 997
Alabama Power | Pension plans | Fixed income
Assets:
Target Allocation	30%	23%
Actual Allocation	28%	22%
Alabama Power | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 354	$ 291
Alabama Power | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	7	2
Alabama Power | Pension plans | Corporate bonds
Assets:
Plan assets	360	421
Alabama Power | Pension plans | Pooled funds
Assets:
Plan assets	146	186
Alabama Power | Pension plans | Cash equivalents and other
Assets:
Plan assets	98	99
Alabama Power | Pension plans | Real estate investments
Assets:
Plan assets	$ 546	$ 660
Target Allocation	13%	14%
Actual Allocation	15%	15%
Alabama Power | Pension plans | Special situations
Assets:
Plan assets	$ 45	$ 41
Target Allocation	3%	3%
Actual Allocation	2%	1%
Alabama Power | Pension plans | Private equity
Assets:
Plan assets	$ 414	$ 382
Target Allocation	9%	9%
Actual Allocation	12%	9%
Alabama Power | Other postretirement benefit plans
Assets:
Plan assets	$ 371	$ 488
Target Allocation	100%	100%
Actual Allocation	100%	100%
Alabama Power | Other postretirement benefit plans | Equity
Assets:
Target Allocation	69%	71%
Actual Allocation	65%	69%
Alabama Power | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	$ 23	$ 37
Alabama Power | Other postretirement benefit plans | International equity
Assets:
Plan assets	$ 27	$ 35
Alabama Power | Other postretirement benefit plans | Fixed income
Assets:
Target Allocation	23%	21%
Actual Allocation	23%	21%
Alabama Power | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 12	$ 10
Alabama Power | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	12	18
Alabama Power | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	7	6
Alabama Power | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	3	3
Alabama Power | Other postretirement benefit plans | Trust-owned life insurance
Assets:
Plan assets	252	341
Alabama Power | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	$ 19	$ 23
Target Allocation	4%	4%
Actual Allocation	7%	7%
Alabama Power | Other postretirement benefit plans | Special situations
Assets:
Plan assets	$ 2	$ 2
Target Allocation	1%	1%
Actual Allocation	1%	0%
Alabama Power | Other postretirement benefit plans | Private equity
Assets:
Plan assets	$ 14	$ 13
Target Allocation	3%	3%
Actual Allocation	4%	3%
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans
Assets:
Plan assets	$ 1,209	$ 1,669
Derivatives	(1)
Defined Benefit Plan, Plan Assets, Amount, Excluding Cash, Investment Income And Pending Investment Sales Receivables, And Pending Investment Purchase Payables	1,208
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Domestic equity
Assets:
Plan assets	500	743
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | International equity
Assets:
Plan assets	522	659
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Cash equivalents and other
Assets:
Plan assets	96	97
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Real estate investments
Assets:
Plan assets	91	170
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Special situations
Assets:
Plan assets	0	0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private equity
Assets:
Plan assets	0	0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans
Assets:
Plan assets	41	58
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	17	26
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | International equity
Assets:
Plan assets	18	23
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	0	0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	0	0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	3	3
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Trust-owned life insurance
Assets:
Plan assets	0	0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	3	6
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Special situations
Assets:
Plan assets	0	0
Alabama Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	0	0
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans
Assets:
Plan assets	1,299	1,558
Derivatives	0
Defined Benefit Plan, Plan Assets, Amount, Excluding Cash, Investment Income And Pending Investment Sales Receivables, And Pending Investment Purchase Payables	1,299
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Domestic equity
Assets:
Plan assets	167	319
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | International equity
Assets:
Plan assets	263	337
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	354	291
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	7	2
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Corporate bonds
Assets:
Plan assets	360	421
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Pooled funds
Assets:
Plan assets	146	186
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Cash equivalents and other
Assets:
Plan assets	2	2
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Real estate investments
Assets:
Plan assets	0	0
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Special situations
Assets:
Plan assets	0	0
Alabama Power | Significant Other Observable Inputs (Level 2) | Pension plans | Private equity
Assets:
Plan assets	0	0
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans
Assets:
Plan assets	298	398
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	6	11
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | International equity
Assets:
Plan assets	9	12
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	12	10
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	12	18
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	7	6
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	0	0
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Trust-owned life insurance
Assets:
Plan assets	252	341
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	0	0
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Special situations
Assets:
Plan assets	0	0
Alabama Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	0	0
Alabama Power | Significant Unobservable Inputs (Level 3) | Pension plans
Assets:
Plan assets	0	1
Alabama Power | Significant Unobservable Inputs (Level 3) | Pension plans | Domestic equity
Assets:
Plan assets	0	0
Alabama Power | Significant Unobservable Inputs (Level 3) | Pension plans | International equity
Assets:
Plan assets	0	1
Alabama Power | Significant Unobservable Inputs (Level 3) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Alabama Power | Significant Unobservable Inputs (Level 3) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Alabama Power | Significant Unobservable Inputs (Level 3) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Alabama Power | Significant Unobservable Inputs (Level 3) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Alabama Power | Significant Unobservable Inputs (Level 3) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Alabama Power | Significant Unobservable Inputs (Level 3) | Pension plans | Real estate investments
Assets:
Plan assets	0	0
Alabama Power | Significant Unobservable Inputs (Level 3) | Pension plans | Special situations
Assets:
Plan assets	0	0
Alabama Power | Significant Unobservable Inputs (Level 3) | Pension plans | Private equity
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans
Assets:
Plan assets	914	913
Derivatives	0
Defined Benefit Plan, Plan Assets, Amount, Excluding Cash, Investment Income And Pending Investment Sales Receivables, And Pending Investment Purchase Payables	914
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Domestic equity
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | International equity
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Real estate investments
Assets:
Plan assets	455	490
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Special situations
Assets:
Plan assets	45	41
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private equity
Assets:
Plan assets	414	382
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans
Assets:
Plan assets	32	32
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | International equity
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Trust-owned life insurance
Assets:
Plan assets	0	0
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	16	17
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Special situations
Assets:
Plan assets	2	2
Alabama Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	$ 14	13
Georgia Power
Assets:
Target Allocation	100%
Actual Allocation	100%
Georgia Power | Pension plans
Assets:
Plan assets	$ 4,448	$ 5,415
Target Allocation	100%	100%
Actual Allocation	100%	100%
Derivatives	$ (1)
Defined Benefit Plan, Plan Assets, Amount, Excluding Cash, Investment Income And Pending Investment Sales Receivables, And Pending Investment Purchase Payables	$ 4,447
Georgia Power | Pension plans | Equity
Assets:
Target Allocation	45%	51%
Actual Allocation	43%	53%
Georgia Power | Pension plans | Domestic equity
Assets:
Plan assets	$ 868	$ 1,389
Georgia Power | Pension plans | International equity
Assets:
Plan assets	$ 1,020	$ 1,303
Georgia Power | Pension plans | Fixed income
Assets:
Target Allocation	30%	23%
Actual Allocation	28%	22%
Georgia Power | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 460	$ 380
Georgia Power | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	9	3
Georgia Power | Pension plans | Corporate bonds
Assets:
Plan assets	468	551
Georgia Power | Pension plans | Pooled funds
Assets:
Plan assets	190	243
Georgia Power | Pension plans | Cash equivalents and other
Assets:
Plan assets	127	129
Georgia Power | Pension plans | Real estate investments
Assets:
Plan assets	$ 709	$ 863
Target Allocation	13%	14%
Actual Allocation	15%	15%
Georgia Power | Pension plans | Special situations
Assets:
Plan assets	$ 59	$ 54
Target Allocation	3%	3%
Actual Allocation	2%	1%
Georgia Power | Pension plans | Private equity
Assets:
Plan assets	$ 538	$ 500
Target Allocation	9%	9%
Actual Allocation	12%	9%
Georgia Power | Other postretirement benefit plans
Assets:
Plan assets	$ 368	$ 450
Target Allocation	100%	100%
Actual Allocation	100%	100%
Georgia Power | Other postretirement benefit plans | Equity
Assets:
Target Allocation	58%	60%
Actual Allocation	56%	62%
Georgia Power | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	$ 52	$ 78
Georgia Power | Other postretirement benefit plans | International equity
Assets:
Plan assets	$ 56	$ 72
Georgia Power | Other postretirement benefit plans | Fixed income
Assets:
Target Allocation	35%	33%
Actual Allocation	34%	30%
Georgia Power | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 10	$ 9
Georgia Power | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	12	14
Georgia Power | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	40	46
Georgia Power | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	9	5
Georgia Power | Other postretirement benefit plans | Trust-owned life insurance
Assets:
Plan assets	154	189
Georgia Power | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	$ 19	$ 23
Target Allocation	4%	4%
Actual Allocation	5%	5%
Georgia Power | Other postretirement benefit plans | Special situations
Assets:
Plan assets	$ 2	$ 1
Target Allocation	1%	1%
Actual Allocation	1%	0%
Georgia Power | Other postretirement benefit plans | Private equity
Assets:
Plan assets	$ 14	$ 13
Target Allocation	2%	2%
Actual Allocation	4%	3%
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans
Assets:
Plan assets	$ 1,572	$ 2,182
Derivatives	(1)
Defined Benefit Plan, Plan Assets, Amount, Excluding Cash, Investment Income And Pending Investment Sales Receivables, And Pending Investment Purchase Payables	1,571
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Domestic equity
Assets:
Plan assets	651	972
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | International equity
Assets:
Plan assets	678	861
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Cash equivalents and other
Assets:
Plan assets	125	127
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Real estate investments
Assets:
Plan assets	118	222
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Special situations
Assets:
Plan assets	0	0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private equity
Assets:
Plan assets	0	0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans
Assets:
Plan assets	76	99
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	46	65
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | International equity
Assets:
Plan assets	17	22
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	0	0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	0	0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	9	5
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Trust-owned life insurance
Assets:
Plan assets	0	0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	4	7
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Special situations
Assets:
Plan assets	0	0
Georgia Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	0	0
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans
Assets:
Plan assets	1,688	2,037
Derivatives	0
Defined Benefit Plan, Plan Assets, Amount, Excluding Cash, Investment Income And Pending Investment Sales Receivables, And Pending Investment Purchase Payables	1,688
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Domestic equity
Assets:
Plan assets	217	417
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | International equity
Assets:
Plan assets	342	441
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	460	380
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	9	3
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Corporate bonds
Assets:
Plan assets	468	551
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Pooled funds
Assets:
Plan assets	190	243
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Cash equivalents and other
Assets:
Plan assets	2	2
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Real estate investments
Assets:
Plan assets	0	0
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Special situations
Assets:
Plan assets	0	0
Georgia Power | Significant Other Observable Inputs (Level 2) | Pension plans | Private equity
Assets:
Plan assets	0	0
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans
Assets:
Plan assets	261	321
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	6	13
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | International equity
Assets:
Plan assets	39	50
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	10	9
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	12	14
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	40	46
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	0	0
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Trust-owned life insurance
Assets:
Plan assets	154	189
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	0	0
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Special situations
Assets:
Plan assets	0	0
Georgia Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	0	0
Georgia Power | Significant Unobservable Inputs (Level 3) | Pension plans
Assets:
Plan assets	0	1
Georgia Power | Significant Unobservable Inputs (Level 3) | Pension plans | Domestic equity
Assets:
Plan assets	0	0
Georgia Power | Significant Unobservable Inputs (Level 3) | Pension plans | International equity
Assets:
Plan assets	0	1
Georgia Power | Significant Unobservable Inputs (Level 3) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Georgia Power | Significant Unobservable Inputs (Level 3) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Georgia Power | Significant Unobservable Inputs (Level 3) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Georgia Power | Significant Unobservable Inputs (Level 3) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Georgia Power | Significant Unobservable Inputs (Level 3) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Georgia Power | Significant Unobservable Inputs (Level 3) | Pension plans | Real estate investments
Assets:
Plan assets	0	0
Georgia Power | Significant Unobservable Inputs (Level 3) | Pension plans | Special situations
Assets:
Plan assets	0	0
Georgia Power | Significant Unobservable Inputs (Level 3) | Pension plans | Private equity
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans
Assets:
Plan assets	1,188	1,195
Derivatives	0
Defined Benefit Plan, Plan Assets, Amount, Excluding Cash, Investment Income And Pending Investment Sales Receivables, And Pending Investment Purchase Payables	1,188
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Domestic equity
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | International equity
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Real estate investments
Assets:
Plan assets	591	641
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Special situations
Assets:
Plan assets	59	54
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private equity
Assets:
Plan assets	538	500
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans
Assets:
Plan assets	31	30
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | International equity
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Trust-owned life insurance
Assets:
Plan assets	0	0
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	15	16
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Special situations
Assets:
Plan assets	2	1
Georgia Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	14	13
Mississippi Power | Pension plans
Assets:
Plan assets	$ 648	$ 787
Target Allocation	100%	100%
Actual Allocation	100%	100%
Mississippi Power | Pension plans | Equity
Assets:
Target Allocation	45%	51%
Actual Allocation	43%	53%
Mississippi Power | Pension plans | Domestic equity
Assets:
Plan assets	$ 127	$ 203
Mississippi Power | Pension plans | International equity
Assets:
Plan assets	$ 149	$ 190
Mississippi Power | Pension plans | Fixed income
Assets:
Target Allocation	30%	23%
Actual Allocation	28%	22%
Mississippi Power | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 67	$ 55
Mississippi Power | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	1
Mississippi Power | Pension plans | Corporate bonds
Assets:
Plan assets	68	80
Mississippi Power | Pension plans | Pooled funds
Assets:
Plan assets	28	35
Mississippi Power | Pension plans | Cash equivalents and other
Assets:
Plan assets	18	18
Mississippi Power | Pension plans | Real estate investments
Assets:
Plan assets	$ 103	$ 125
Target Allocation	13%	14%
Actual Allocation	15%	15%
Mississippi Power | Pension plans | Special situations
Assets:
Plan assets	$ 9	$ 8
Target Allocation	3%	3%
Actual Allocation	2%	1%
Mississippi Power | Pension plans | Private equity
Assets:
Plan assets	$ 78	$ 73
Target Allocation	9%	9%
Actual Allocation	12%	9%
Mississippi Power | Other postretirement benefit plans
Assets:
Plan assets	$ 24	$ 27
Target Allocation	100%	100%
Actual Allocation	100%	100%
Mississippi Power | Other postretirement benefit plans | Equity
Assets:
Target Allocation	37%	43%
Actual Allocation	35%	44%
Mississippi Power | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	$ 4	$ 6
Mississippi Power | Other postretirement benefit plans | International equity
Assets:
Plan assets	$ 5	$ 6
Mississippi Power | Other postretirement benefit plans | Fixed income
Assets:
Target Allocation	43%	36%
Actual Allocation	41%	34%
Mississippi Power | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 4	$ 5
Mississippi Power | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	2	2
Mississippi Power | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	1	1
Mississippi Power | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	2	1
Mississippi Power | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	$ 4	$ 4
Target Allocation	11%	11%
Actual Allocation	12%	13%
Mississippi Power | Other postretirement benefit plans | Special situations
Assets:
Plan assets	$ 0	$ 0
Target Allocation	2%	2%
Actual Allocation	2%	1%
Mississippi Power | Other postretirement benefit plans | Private equity
Assets:
Plan assets	$ 2	$ 2
Target Allocation	7%	8%
Actual Allocation	10%	8%
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans
Assets:
Plan assets	$ 229	$ 318
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Domestic equity
Assets:
Plan assets	95	142
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | International equity
Assets:
Plan assets	99	126
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Cash equivalents and other
Assets:
Plan assets	18	18
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Real estate investments
Assets:
Plan assets	17	32
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Special situations
Assets:
Plan assets	0	0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private equity
Assets:
Plan assets	0	0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans
Assets:
Plan assets	9	10
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	3	4
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | International equity
Assets:
Plan assets	3	4
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	0	0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	0	0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	2	1
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	1	1
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Special situations
Assets:
Plan assets	0	0
Mississippi Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	0	0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans
Assets:
Plan assets	246	295
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Domestic equity
Assets:
Plan assets	32	61
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | International equity
Assets:
Plan assets	50	64
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	67	55
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	1
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Corporate bonds
Assets:
Plan assets	68	80
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Pooled funds
Assets:
Plan assets	28	35
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Real estate investments
Assets:
Plan assets	0	0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Special situations
Assets:
Plan assets	0	0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Pension plans | Private equity
Assets:
Plan assets	0	0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans
Assets:
Plan assets	10	12
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	1	2
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | International equity
Assets:
Plan assets	2	2
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	4	5
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	2	2
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	1	1
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	0	0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	0	0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Special situations
Assets:
Plan assets	0	0
Mississippi Power | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	0	0
Mississippi Power | Significant Unobservable Inputs (Level 3) | Pension plans
Assets:
Plan assets	0	0
Mississippi Power | Significant Unobservable Inputs (Level 3) | Pension plans | Domestic equity
Assets:
Plan assets	0	0
Mississippi Power | Significant Unobservable Inputs (Level 3) | Pension plans | International equity
Assets:
Plan assets	0	0
Mississippi Power | Significant Unobservable Inputs (Level 3) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Mississippi Power | Significant Unobservable Inputs (Level 3) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0
Mississippi Power | Significant Unobservable Inputs (Level 3) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Mississippi Power | Significant Unobservable Inputs (Level 3) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Mississippi Power | Significant Unobservable Inputs (Level 3) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Mississippi Power | Significant Unobservable Inputs (Level 3) | Pension plans | Real estate investments
Assets:
Plan assets	0	0
Mississippi Power | Significant Unobservable Inputs (Level 3) | Pension plans | Special situations
Assets:
Plan assets	0	0
Mississippi Power | Significant Unobservable Inputs (Level 3) | Pension plans | Private equity
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans
Assets:
Plan assets	173	174
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Domestic equity
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | International equity
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Real estate investments
Assets:
Plan assets	86	93
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Special situations
Assets:
Plan assets	9	8
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private equity
Assets:
Plan assets	78	73
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans
Assets:
Plan assets	5	5
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | International equity
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	3	3
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Special situations
Assets:
Plan assets	0	0
Mississippi Power | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	2	2
Southern Power | Pension plans
Assets:
Plan assets	$ 177	$ 213
Target Allocation	100%	100%
Actual Allocation	100%	100%
Southern Power | Pension plans | Equity
Assets:
Target Allocation	45%	51%
Actual Allocation	43%	53%
Southern Power | Pension plans | Domestic equity
Assets:
Plan assets	$ 34	$ 54
Southern Power | Pension plans | International equity
Assets:
Plan assets	$ 41	$ 51
Southern Power | Pension plans | Fixed income
Assets:
Target Allocation	30%	23%
Actual Allocation	28%	22%
Southern Power | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 18	$ 15
Southern Power | Pension plans | Corporate bonds
Assets:
Plan assets	19	22
Southern Power | Pension plans | Pooled funds
Assets:
Plan assets	8	10
Southern Power | Pension plans | Cash equivalents and other
Assets:
Plan assets	5	5
Southern Power | Pension plans | Real estate investments
Assets:
Plan assets	$ 29	$ 34
Target Allocation	13%	14%
Actual Allocation	15%	15%
Southern Power | Pension plans | Special situations
Assets:
Plan assets	$ 2	$ 2
Target Allocation	3%	3%
Actual Allocation	2%	1%
Southern Power | Pension plans | Private equity
Assets:
Plan assets	$ 21	$ 20
Target Allocation	9%	9%
Actual Allocation	12%	9%
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans
Assets:
Plan assets	$ 62	$ 86
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Domestic equity
Assets:
Plan assets	25	38
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | International equity
Assets:
Plan assets	27	34
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Cash equivalents and other
Assets:
Plan assets	5	5
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Real estate investments
Assets:
Plan assets	5	9
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Special situations
Assets:
Plan assets	0	0
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private equity
Assets:
Plan assets	0	0
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans
Assets:
Plan assets	68	80
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Domestic equity
Assets:
Plan assets	9	16
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | International equity
Assets:
Plan assets	14	17
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	18	15
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Corporate bonds
Assets:
Plan assets	19	22
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Pooled funds
Assets:
Plan assets	8	10
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Real estate investments
Assets:
Plan assets	0	0
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Special situations
Assets:
Plan assets	0	0
Southern Power | Significant Other Observable Inputs (Level 2) | Pension plans | Private equity
Assets:
Plan assets	0	0
Southern Power | Significant Unobservable Inputs (Level 3) | Pension plans
Assets:
Plan assets	0	0
Southern Power | Significant Unobservable Inputs (Level 3) | Pension plans | Domestic equity
Assets:
Plan assets	0	0
Southern Power | Significant Unobservable Inputs (Level 3) | Pension plans | International equity
Assets:
Plan assets	0	0
Southern Power | Significant Unobservable Inputs (Level 3) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Power | Significant Unobservable Inputs (Level 3) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Southern Power | Significant Unobservable Inputs (Level 3) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Southern Power | Significant Unobservable Inputs (Level 3) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Southern Power | Significant Unobservable Inputs (Level 3) | Pension plans | Real estate investments
Assets:
Plan assets	0	0
Southern Power | Significant Unobservable Inputs (Level 3) | Pension plans | Special situations
Assets:
Plan assets	0	0
Southern Power | Significant Unobservable Inputs (Level 3) | Pension plans | Private equity
Assets:
Plan assets	0	0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans
Assets:
Plan assets	47	47
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Domestic equity
Assets:
Plan assets	0	0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | International equity
Assets:
Plan assets	0	0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Real estate investments
Assets:
Plan assets	24	25
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Special situations
Assets:
Plan assets	2	2
Southern Power | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private equity
Assets:
Plan assets	21	20
Southern Company Gas | Pension plans
Assets:
Plan assets	$ 1,001	$ 1,241
Target Allocation	100%	100%
Actual Allocation	100%	100%
Southern Company Gas | Pension plans | Equity
Assets:
Target Allocation	45%	51%
Actual Allocation	43%	53%
Southern Company Gas | Pension plans | Domestic equity
Assets:
Plan assets	$ 195	$ 319
Southern Company Gas | Pension plans | International equity
Assets:
Plan assets	$ 229	$ 298
Southern Company Gas | Pension plans | Fixed income
Assets:
Target Allocation	30%	23%
Actual Allocation	28%	22%
Southern Company Gas | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 104	$ 87
Southern Company Gas | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	2	1
Southern Company Gas | Pension plans | Corporate bonds
Assets:
Plan assets	105	126
Southern Company Gas | Pension plans | Pooled funds
Assets:
Plan assets	43	56
Southern Company Gas | Pension plans | Cash equivalents and other
Assets:
Plan assets	29	29
Southern Company Gas | Pension plans | Real estate investments
Assets:
Plan assets	$ 160	$ 198
Target Allocation	13%	14%
Actual Allocation	15%	15%
Southern Company Gas | Pension plans | Special situations
Assets:
Plan assets	$ 13	$ 12
Target Allocation	3%	3%
Actual Allocation	2%	1%
Southern Company Gas | Pension plans | Private equity
Assets:
Plan assets	$ 121	$ 115
Target Allocation	9%	9%
Actual Allocation	12%	9%
Southern Company Gas | Other postretirement benefit plans
Assets:
Plan assets	$ 113	$ 143
Target Allocation	100%	100%
Actual Allocation	100%	100%
Southern Company Gas | Other postretirement benefit plans | Equity
Assets:
Target Allocation	72%	72%
Actual Allocation	70%	73%
Southern Company Gas | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	$ 58	$ 79
Southern Company Gas | Other postretirement benefit plans | International equity
Assets:
Plan assets	$ 22	$ 26
Southern Company Gas | Other postretirement benefit plans | Fixed income
Assets:
Target Allocation	26%	26%
Actual Allocation	27%	24%
Southern Company Gas | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	$ 1	$ 1
Southern Company Gas | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	1	1
Southern Company Gas | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	27	30
Southern Company Gas | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	1	2
Southern Company Gas | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	$ 2	$ 3
Target Allocation	1%	1%
Actual Allocation	2%	2%
Southern Company Gas | Other postretirement benefit plans | Private equity
Assets:
Plan assets	$ 1	$ 1
Target Allocation	1%	1%
Actual Allocation	1%	1%
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans
Assets:
Plan assets	$ 353	$ 500
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Domestic equity
Assets:
Plan assets	146	223
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | International equity
Assets:
Plan assets	152	197
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Cash equivalents and other
Assets:
Plan assets	28	29
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Real estate investments
Assets:
Plan assets	27	51
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Special situations
Assets:
Plan assets	0	0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Pension plans | Private equity
Assets:
Plan assets	0	0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans
Assets:
Plan assets	5	8
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	2	3
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | International equity
Assets:
Plan assets	2	2
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	0	0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	0	0
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	1	2
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	0	1
Southern Company Gas | Quoted Prices in Active Markets for Identical Assets (Level 1) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	0	0
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans
Assets:
Plan assets	381	467
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Domestic equity
Assets:
Plan assets	49	96
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | International equity
Assets:
Plan assets	77	101
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	104	87
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	2	1
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Corporate bonds
Assets:
Plan assets	105	126
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Pooled funds
Assets:
Plan assets	43	56
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Cash equivalents and other
Assets:
Plan assets	1	0
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Real estate investments
Assets:
Plan assets	0	0
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Special situations
Assets:
Plan assets	0	0
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Pension plans | Private equity
Assets:
Plan assets	0	0
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans
Assets:
Plan assets	105	132
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	56	76
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | International equity
Assets:
Plan assets	20	24
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	1	1
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	1	1
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	27	30
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	0	0
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	0	0
Southern Company Gas | Significant Other Observable Inputs (Level 2) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	0	0
Southern Company Gas | Significant Unobservable Inputs (Level 3) | Pension plans
Assets:
Plan assets	0	0
Southern Company Gas | Significant Unobservable Inputs (Level 3) | Pension plans | Domestic equity
Assets:
Plan assets	0	0
Southern Company Gas | Significant Unobservable Inputs (Level 3) | Pension plans | International equity
Assets:
Plan assets	0	0
Southern Company Gas | Significant Unobservable Inputs (Level 3) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Company Gas | Significant Unobservable Inputs (Level 3) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Southern Company Gas | Significant Unobservable Inputs (Level 3) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Southern Company Gas | Significant Unobservable Inputs (Level 3) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Southern Company Gas | Significant Unobservable Inputs (Level 3) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Southern Company Gas | Significant Unobservable Inputs (Level 3) | Pension plans | Real estate investments
Assets:
Plan assets	0	0
Southern Company Gas | Significant Unobservable Inputs (Level 3) | Pension plans | Special situations
Assets:
Plan assets	0	0
Southern Company Gas | Significant Unobservable Inputs (Level 3) | Pension plans | Private equity
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans
Assets:
Plan assets	267	274
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Domestic equity
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | International equity
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Mortgage- and asset-backed securities
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Corporate bonds
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Pooled funds
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Cash equivalents and other
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Real estate investments
Assets:
Plan assets	133	147
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Special situations
Assets:
Plan assets	13	12
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Pension plans | Private equity
Assets:
Plan assets	121	115
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans
Assets:
Plan assets	3	3
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Domestic equity
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | International equity
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | U.S. Treasury, government, and agency bonds
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Corporate bonds
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Pooled funds
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Cash equivalents and other
Assets:
Plan assets	0	0
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Real estate investments
Assets:
Plan assets	2	2
Southern Company Gas | Net Asset Value as a Practical Expedient (NAV) | Other postretirement benefit plans | Private equity
Assets:
Plan assets	$ 1	$ 1

RETIREMENT BENEFITS - 401K Plan

RETIREMENT BENEFITS - 401K Plan Matching Contributions (Details) - Employee Savings Plan - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	$ 124	$ 119	$ 120
Alabama Power
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	26	26	26
Georgia Power
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	29	28	29
Mississippi Power
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	5	5	5
Southern Power
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	3	2	2
Southern Company Gas
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, cost	$ 17	$ 16	$ 16

STOCK COMPENSATION - Schedule o

STOCK COMPENSATION - Schedule of Employees Participating in Stock-Based Compensation Programs (Details)	Dec. 31, 2022 employee
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees	1,586
Alabama Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees	221
Georgia Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees	236
Mississippi Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees	64
Southern Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees	45
Southern Company Gas
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Number of employees	186

STOCK COMPENSATION - Performanc

STOCK COMPENSATION - Performance Shares Narrative (Details) $ / shares in Units, $ in Millions	1 Months Ended		12 Months Ended
	Feb. 28, 2023 $ / shares shares	Feb. 28, 2022 $ / shares shares	Dec. 31, 2022 USD ($) type $ / shares shares	Dec. 31, 2021 $ / shares shares	Dec. 31, 2020 $ / shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares converted (in shares)		2,500,000
Shares converted (in dollars per share) | $ / shares		$ 66.57
Subsequent Event
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares converted (in shares)	1,800,000
Shares converted (in dollars per share) | $ / shares	$ 67.13
Performance Shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of performance share units issued under performance share plan			3 years	3 years
Minimum percentage of transfer performance shares to common stock based on actual total shareholder return			0%
Maximum percentage of transfer performance shares to common stock based on actual total shareholder return			200%
Number of types of PSUs | type			3
Performance share units, unvested (in shares)			2,400,000	2,200,000
Equity instrument, granted (in shares)			1,300,000
Equity instruments, vested (in shares)			1,100,000
Unrecognized compensation cost | $			$ 31
Total unrecognized compensation cost related to award, weighted average period			19 months
EPS-based and ROE-based Performance Share Units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Vesting period of performance share units issued under performance share plan			3 years
Equity instrument granted in period, weighted average grant date fair value (in dollars per share) | $ / shares			$ 66.87	$ 59.49	$ 68.42

STOCK COMPENSATION - Performa_2

STOCK COMPENSATION - Performance Shares, Assumptions Used (Details) - Performance Shares - $ / shares	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expected volatility	29.60%	30%	15.40%
Expected term (in years)	3 years	3 years	3 years
Interest rate	1.70%	0.20%	1.40%
Weighted average grant-date fair value (in dollars per share)	$ 79.69	$ 69.06	$ 77.65

STOCK COMPENSATION - Performa_3

STOCK COMPENSATION - Performance Shares, Compensation Costs and Related Tax Benefit (Details) - Performance Shares - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost recognized in income	$ 101	$ 112	$ 84
Tax benefit of compensation cost recognized in income	26	29	22
Southern Company Gas
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Compensation cost recognized in income	12	17	13
Tax benefit of compensation cost recognized in income	$ 4	$ 4	$ 4

STOCK COMPENSATION - Restricted

STOCK COMPENSATION - Restricted Stock Units Narrative (Details) - Restricted Stock Units (RSUs) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Equity instrument granted in period, weighted average grant date fair value (in dollars per share)	$ 67.20	$ 59.56	$ 67.60
Award requisite service period	3 years
Total unrecognized compensation cost related to award, weighted average period	18 months
Restricted stock units, unvested (in shares)	0.9	1.1
Equity instrument, granted (in shares)	0.4
Vested or forfeited (in shares)	0.6
Total compensation cost for award recognized in income	$ 26	$ 32	$ 29
Total compensation cost for award recognized in income, tax benefit	$ 7	$ 8	$ 8
One-year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to award, weighted average period	1 year
Two-year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to award, weighted average period	2 years
Three-year vesting period
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation cost related to award, weighted average period	3 years

STOCK COMPENSATION - Stock Opti

STOCK COMPENSATION - Stock Options Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Weighted average remaining contractual term for options outstanding	10 months
Cash received from issuance related to option exercise	$ 75	$ 66	$ 66
Stock Options | Maximum
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Expiration period	10 years

STOCK COMPENSATION - Stock Op_2

STOCK COMPENSATION - Stock Option Activity (Details) shares in Millions	12 Months Ended
	Dec. 31, 2022 $ / shares shares
Shares Subject to Option
Beginning balance (in shares) | shares	2.8
Exercised (in shares) | shares	1.8
Ending balance (in shares) | shares	1
Weighted Average Exercise Price
Beginning balance (in dollars per share) | $ / shares	$ 42.95
Exercised (in dollars per share) | $ / shares	43.37
Ending balance (in dollars per share) | $ / shares	$ 42.22

STOCK COMPENSATION - Aggregate

STOCK COMPENSATION - Aggregate Intrinsic Value for Options Exercised (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	$ 29
Aggregate intrinsic value for options exercisable	29
Intrinsic value of options exercised	49	$ 34	$ 38
Tax benefit of options exercised	12	7	9
Georgia Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	0
Intrinsic value of options exercised	15	14	9
Tax benefit of options exercised	4	$ 3	$ 2
Southern Company Gas
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	0
Mississippi Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	0
Alabama Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	0
Southern Power
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Aggregate intrinsic value for options outstanding	0
Aggregate intrinsic value for options exercisable	$ 0

FAIR VALUE MEASUREMENTS - Asset

FAIR VALUE MEASUREMENTS - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Assets:
Derivative asset	$ 141	$ 213
Liabilities:
Derivative liability	617	125
Collateral already posted, aggregate fair value	41
Recurring
Assets:
Cash equivalents	1,447	1,174
Other investments	35	44
Total	3,856	4,023
Liabilities:
Contingent consideration	12	14
Other	13
Total	753	181
Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	1,427	1,160
Other investments	9	9
Total	2,271	2,174
Liabilities:
Contingent consideration	0	0
Other	0
Total	32	10
Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	20	14
Other investments	26	35
Total	1,424	1,699
Liabilities:
Contingent consideration	0	0
Other	13
Total	709	157
Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0	0
Other investments	0	0
Total	0	0
Liabilities:
Contingent consideration	12	14
Other	0
Total	12	14
Recurring | Fair Value Measured at Net Asset Value Per Share (NAV)
Assets:
Total	161	150
Alabama Power
Assets:
Derivative asset	38	50
Liabilities:
Derivative liability	15	6
Collateral already posted, aggregate fair value	0
Alabama Power | Recurring
Assets:
Cash equivalents	458	853
Other investments	26	35
Total	1,671	2,267
Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	438	839
Other investments	0	0
Total	966	1,482
Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	20	14
Other investments	26	35
Total	544	635
Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0	0
Other investments	0	0
Total	0	0
Alabama Power | Recurring | Fair Value Measured at Net Asset Value Per Share (NAV)
Assets:
Total	161	150
Georgia Power
Assets:
Derivative asset	21	67
Liabilities:
Derivative liability	41	0
Georgia Power | Recurring
Assets:
Cash equivalents	355
Total	1,415	1,292
Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	355
Total	640	336
Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	0
Total	775	956
Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0
Total	0	0
Mississippi Power
Assets:
Derivative asset	42	52
Liabilities:
Derivative liability	15	1
Mississippi Power | Recurring
Assets:
Cash equivalents	47	40
Total	106	96
Mississippi Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	47	40
Total	47	40
Mississippi Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	0	0
Total	59	56
Mississippi Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0	0
Total	0	0
Southern Power
Assets:
Derivative asset	8	4
Liabilities:
Derivative liability	59	16
Other		13
Collateral already posted, aggregate fair value	15
Southern Power | Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Other		0
Southern Power | Significant Other Observable Inputs (Level 2)
Liabilities:
Other		13
Southern Power | Significant Unobservable Inputs (Level 3)
Liabilities:
Other		0
Southern Power | Recurring
Liabilities:
Contingent consideration	12
Other	13
Total	84	43
Southern Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Contingent consideration	0
Other	0
Total	0	0
Southern Power | Recurring | Significant Other Observable Inputs (Level 2)
Liabilities:
Contingent consideration	0
Other	13
Total	72	29
Southern Power | Recurring | Significant Unobservable Inputs (Level 3)
Liabilities:
Contingent consideration	12
Other	0
Total	12	14
Southern Company Gas
Assets:
Derivative asset	28	27
Liabilities:
Derivative liability	110	16
Collateral already posted, aggregate fair value	41	3
Southern Company Gas | Recurring
Assets:
Cash equivalents	50	2
Total	98	61
Liabilities:
Total	151	27
Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	50	2
Total	72	26
Liabilities:
Total	32	10
Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	0	0
Total	26	35
Liabilities:
Total	119	17
Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0	0
Total	0	0
Liabilities:
Total	0	0
Energy-related derivatives | Recurring
Assets:
Derivative asset	199	219
Liabilities:
Derivative liability	210	46
Energy-related derivatives | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset	18	24
Liabilities:
Derivative liability	32	10
Energy-related derivatives | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset	181	195
Liabilities:
Derivative liability	178	36
Energy-related derivatives | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives | Alabama Power | Recurring
Assets:
Derivative asset	62	55
Liabilities:
Derivative liability	39	11
Energy-related derivatives | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset	62	55
Liabilities:
Derivative liability	39	11
Energy-related derivatives | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives | Georgia Power | Recurring
Assets:
Derivative asset	42	75
Liabilities:
Derivative liability	62	8
Energy-related derivatives | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset	42	75
Liabilities:
Derivative liability	62	8
Energy-related derivatives | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives | Mississippi Power | Recurring
Assets:
Derivative asset	59	56
Liabilities:
Derivative liability	32	5
Energy-related derivatives | Mississippi Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives | Mississippi Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset	59	56
Liabilities:
Derivative liability	32	5
Energy-related derivatives | Mississippi Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Energy-related derivatives | Southern Power | Recurring
Assets:
Derivative asset	8	4
Liabilities:
Derivative liability	12
Energy-related derivatives | Southern Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0
Energy-related derivatives | Southern Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset	8	4
Liabilities:
Derivative liability	12
Energy-related derivatives | Southern Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0
Energy-related derivatives | Southern Company Gas | Recurring
Assets:
Derivative asset	28	29
Liabilities:
Derivative liability	65	22
Energy-related derivatives | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset	18	24
Liabilities:
Derivative liability	32	10
Energy-related derivatives | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset	10	5
Liabilities:
Derivative liability	33	12
Energy-related derivatives | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Interest rate derivatives | Recurring
Assets:
Derivative asset	12	19
Liabilities:
Derivative liability	302	29
Interest rate derivatives | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Interest rate derivatives | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset	12	19
Liabilities:
Derivative liability	302	29
Interest rate derivatives | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset	0	0
Liabilities:
Derivative liability	0	0
Interest rate derivatives | Southern Company Gas | Recurring
Assets:
Derivative asset		6
Liabilities:
Derivative liability	86	5
Interest rate derivatives | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivative asset		0
Liabilities:
Derivative liability	0	0
Interest rate derivatives | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Derivative asset		6
Liabilities:
Derivative liability	86	5
Interest rate derivatives | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Derivative asset		0
Liabilities:
Derivative liability	0	0
Foreign currency derivatives | Recurring
Liabilities:
Derivative liability	216	79
Foreign currency derivatives | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Derivative liability	0	0
Foreign currency derivatives | Recurring | Significant Other Observable Inputs (Level 2)
Liabilities:
Derivative liability	216	79
Foreign currency derivatives | Recurring | Significant Unobservable Inputs (Level 3)
Liabilities:
Derivative liability	0	0
Foreign currency derivatives | Southern Power | Recurring
Liabilities:
Derivative liability	47	16
Contingent consideration		14
Foreign currency derivatives | Southern Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Derivative liability	0	0
Contingent consideration		0
Foreign currency derivatives | Southern Power | Recurring | Significant Other Observable Inputs (Level 2)
Liabilities:
Derivative liability	47	16
Contingent consideration		0
Foreign currency derivatives | Southern Power | Recurring | Significant Unobservable Inputs (Level 3)
Liabilities:
Derivative liability	0	0
Contingent consideration		14
Domestic equity | Recurring
Assets:
Nuclear decommissioning trusts	829	1,016
Domestic equity | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	651	791
Domestic equity | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	178	225
Domestic equity | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Domestic equity | Alabama Power | Recurring
Assets:
Nuclear decommissioning trusts	565	684
Domestic equity | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	396	468
Domestic equity | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	169	216
Domestic equity | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Domestic equity | Georgia Power | Recurring
Assets:
Nuclear decommissioning trusts	256	324
Domestic equity | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	255	323
Domestic equity | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	1	1
Domestic equity | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Domestic equity | Southern Company Gas | Recurring
Assets:
Non-qualified deferred compensation trusts	8	8
Domestic equity | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Non-qualified deferred compensation trusts	0	0
Domestic equity | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Non-qualified deferred compensation trusts	8	8
Domestic equity | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Non-qualified deferred compensation trusts	0	0
Foreign equity | Recurring
Assets:
Nuclear decommissioning trusts	275	353
Foreign equity | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	125	165
Foreign equity | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	150	188
Foreign equity | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Foreign equity | Alabama Power | Recurring
Assets:
Nuclear decommissioning trusts	125	165
Foreign equity | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	125	165
Foreign equity | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	0	0
Foreign equity | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Foreign equity | Georgia Power | Recurring
Assets:
Nuclear decommissioning trusts	149	185
Foreign equity | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Foreign equity | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	149	185
Foreign equity | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Foreign equity | Southern Company Gas | Recurring
Assets:
Non-qualified deferred compensation trusts	1	3
Foreign equity | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Non-qualified deferred compensation trusts	0	0
Foreign equity | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Non-qualified deferred compensation trusts	1	3
Foreign equity | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Non-qualified deferred compensation trusts	0	0
U.S. Treasury and government agency securities | Recurring
Assets:
Nuclear decommissioning trusts	285	314
U.S. Treasury and government agency securities | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
U.S. Treasury and government agency securities | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	285	314
U.S. Treasury and government agency securities | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
U.S. Treasury and government agency securities | Alabama Power | Recurring
Assets:
Nuclear decommissioning trusts	19	21
U.S. Treasury and government agency securities | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
U.S. Treasury and government agency securities | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	19	21
U.S. Treasury and government agency securities | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
U.S. Treasury and government agency securities | Georgia Power | Recurring
Assets:
Nuclear decommissioning trusts	266	293
U.S. Treasury and government agency securities | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
U.S. Treasury and government agency securities | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	266	293
U.S. Treasury and government agency securities | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Municipal bonds | Recurring
Assets:
Nuclear decommissioning trusts	51	56
Municipal bonds | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Municipal bonds | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	51	56
Municipal bonds | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Municipal bonds | Alabama Power | Recurring
Assets:
Nuclear decommissioning trusts	1	1
Municipal bonds | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Municipal bonds | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	1	1
Municipal bonds | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Municipal bonds | Georgia Power | Recurring
Assets:
Nuclear decommissioning trusts	50	55
Municipal bonds | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Municipal bonds | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	50	55
Municipal bonds | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Pooled funds – fixed income | Recurring
Assets:
Nuclear decommissioning trusts	7	13
Pooled funds – fixed income | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Pooled funds – fixed income | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	7	13
Pooled funds – fixed income | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Pooled funds – fixed income | Southern Company Gas | Recurring
Assets:
Non-qualified deferred compensation trusts	7	13
Pooled funds – fixed income | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Non-qualified deferred compensation trusts	0	0
Pooled funds – fixed income | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Non-qualified deferred compensation trusts	7	13
Pooled funds – fixed income | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Non-qualified deferred compensation trusts	0	0
Corporate bonds | Recurring
Assets:
Nuclear decommissioning trusts	412	523
Corporate bonds | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	1
Corporate bonds | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	412	522
Corporate bonds | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Corporate bonds | Alabama Power | Recurring
Assets:
Nuclear decommissioning trusts	225	272
Corporate bonds | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	1
Corporate bonds | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	225	271
Corporate bonds | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Corporate bonds | Georgia Power | Recurring
Assets:
Nuclear decommissioning trusts	187	251
Corporate bonds | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Corporate bonds | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	187	251
Corporate bonds | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Mortgage and asset backed securities | Recurring
Assets:
Nuclear decommissioning trusts	90	93
Mortgage and asset backed securities | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Mortgage and asset backed securities | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	90	93
Mortgage and asset backed securities | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Mortgage and asset backed securities | Alabama Power | Recurring
Assets:
Nuclear decommissioning trusts	22	22
Mortgage and asset backed securities | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Mortgage and asset backed securities | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	22	22
Mortgage and asset backed securities | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Mortgage and asset backed securities | Georgia Power | Recurring
Assets:
Nuclear decommissioning trusts	68	71
Mortgage and asset backed securities | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Mortgage and asset backed securities | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	68	71
Mortgage and asset backed securities | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Private equity | Recurring
Assets:
Nuclear decommissioning trusts	161	150
Private equity | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Private equity | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	0	0
Private equity | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Private equity | Recurring | Fair Value Measured at Net Asset Value Per Share (NAV)
Assets:
Nuclear decommissioning trusts	161	150
Private equity | Alabama Power | Recurring
Assets:
Nuclear decommissioning trusts	161	150
Private equity | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	0	0
Private equity | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	0	0
Private equity | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Private equity | Alabama Power | Recurring | Fair Value Measured at Net Asset Value Per Share (NAV)
Assets:
Nuclear decommissioning trusts	161	150
Cash and cash equivalents | Recurring
Assets:
Nuclear decommissioning trusts	4	2
Cash and cash equivalents | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	4	2
Cash and cash equivalents | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	0	0
Cash and cash equivalents | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Cash equivalents | Southern Company Gas | Recurring
Assets:
Non-qualified deferred compensation trusts	4
Cash equivalents | Southern Company Gas | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Non-qualified deferred compensation trusts	4
Cash equivalents | Southern Company Gas | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Non-qualified deferred compensation trusts	0
Cash equivalents | Southern Company Gas | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Non-qualified deferred compensation trusts	0
Other | Recurring
Assets:
Nuclear decommissioning trusts	49	47
Other | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	37	22
Other | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	12	25
Other | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Other | Alabama Power | Recurring
Assets:
Nuclear decommissioning trusts	7	9
Other | Alabama Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	7	9
Other | Alabama Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	0	0
Other | Alabama Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	0	0
Other | Georgia Power | Recurring
Assets:
Nuclear decommissioning trusts	42	38
Other | Georgia Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Nuclear decommissioning trusts	30	13
Other | Georgia Power | Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Nuclear decommissioning trusts	12	25
Other | Georgia Power | Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Nuclear decommissioning trusts	$ 0	0
Other | Southern Power | Recurring
Liabilities:
Derivative liability		13
Other | Southern Power | Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Derivative liability		0
Other | Southern Power | Recurring | Significant Other Observable Inputs (Level 2)
Liabilities:
Derivative liability		13
Other | Southern Power | Recurring | Significant Unobservable Inputs (Level 3)
Liabilities:
Derivative liability		$ 0

FAIR VALUE MEASUREMENTS - Narra

FAIR VALUE MEASUREMENTS - Narrative (Details) - Private equity - Alabama Power - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Option, Quantitative Disclosures [Line Items]
Alternative investment	$ 161	$ 150
Unfunded commitments	$ 78	$ 69

FAIR VALUE MEASUREMENTS - Finan

FAIR VALUE MEASUREMENTS - Financial Instruments, Carrying Amount Not Equal to Fair Value (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying amount	$ 54,600	$ 52,100
Fair value	48,600	57,100
Alabama Power
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying amount	10,600	9,700
Fair value	9,200	10,900
Georgia Power
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying amount	14,700	13,600
Fair value	13,000	15,100
Mississippi Power
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying amount	1,500	1,500
Fair value	1,300	1,600
Southern Power
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying amount	3,000	3,700
Fair value	2,800	4,100
Southern Company Gas
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Carrying amount	7,400	6,900
Fair value	$ 6,500	$ 7,800

DERIVATIVES - Energy-Related De

DERIVATIVES - Energy-Related Derivative Contracts (Details) - Energy-related, Natural Gas MMBTU in Millions	Dec. 31, 2022 MMBTU
Derivative [Line Items]
Net Purchased mmBtu	431
Alabama Power
Derivative [Line Items]
Net Purchased mmBtu	111
Georgia Power
Derivative [Line Items]
Net Purchased mmBtu	125
Mississippi Power
Derivative [Line Items]
Net Purchased mmBtu	94
Southern Power
Derivative [Line Items]
Net Purchased mmBtu	8
Southern Company Gas
Derivative [Line Items]
Net Purchased mmBtu	93
Long | Not Designated as Hedging Instrument | Southern Company Gas
Derivative [Line Items]
Derivative nonmonetary notional amount net long short position volume	98
Short | Not Designated as Hedging Instrument | Southern Company Gas
Derivative [Line Items]
Derivative nonmonetary notional amount net long short position volume	5

DERIVATIVES - Narrative (Detail

DERIVATIVES - Narrative (Details) MMBTU in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) MMBTU	Dec. 31, 2021 USD ($)
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	23
Estimated pre-tax gains (losses) that will be reclassified from OCI to interest expense for the next 12-month period	$ (16,000,000)
Collateral already posted, aggregate fair value	41,000,000
Estimated pre-tax gains (losses) expected to be reclassified from AOCI	$ (27,000,000)
Alabama Power
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	6
Collateral already posted, aggregate fair value	$ 0
Georgia Power
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	8
Mississippi Power
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	3
Southern Power
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	6
Estimated pre-tax gains (losses) that will be reclassified from OCI to interest expense for the next 12-month period	$ 11,000,000
Collateral already posted, aggregate fair value	15,000,000
Estimated pre-tax gains (losses) expected to be reclassified from AOCI	(11,000,000)
Registrants | Derivative Counterparties
Derivative [Line Items]
Collateral already posted, aggregate fair value	0
Southern Company Gas [Member]
Derivative [Line Items]
Collateral already posted, aggregate fair value	41,000,000	$ 3,000,000
Estimated pre-tax gains (losses) expected to be reclassified from AOCI	$ (16,000,000)

DERIVATIVES - Interest Rate Der

DERIVATIVES - Interest Rate Derivatives (Details) - Interest rate derivatives $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)
Derivative [Line Items]
Notional Amount	$ 2,300
Fair Value Gain (Loss) December 31, 2022	(290)
Southern Company | Cash Flow Hedges of Forecasted Debt
Derivative [Line Items]
Notional Amount	$ 400
Weighted Average Interest Rate Paid	3.50%
Fair Value Gain (Loss) December 31, 2022	$ 12
Southern Company | Fair Value Hedges of Existing Debt | March 2028
Derivative [Line Items]
Notional Amount	$ 400
Weighted Average Interest Rate Paid	0.68%
Interest Rate Received	1.75%
Fair Value Gain (Loss) December 31, 2022	$ (55)
Southern Company | Fair Value Hedges of Existing Debt | April 2030
Derivative [Line Items]
Notional Amount	$ 1,000
Weighted Average Interest Rate Paid	2.36%
Interest Rate Received	3.70%
Fair Value Gain (Loss) December 31, 2022	$ (161)
Southern Company Gas [Member] | Fair Value Hedges of Existing Debt
Derivative [Line Items]
Notional Amount	$ 500
Weighted Average Interest Rate Paid	0.38%
Interest Rate Received	1.75%
Fair Value Gain (Loss) December 31, 2022	$ (86)

DERIVATIVES - Foreign Currency

DERIVATIVES - Foreign Currency Derivatives (Details) € in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($)	Dec. 31, 2022 EUR (€)	Dec. 31, 2021 USD ($)
Foreign currency derivatives | Cash Flow Hedges of Forecasted Debt
Derivative [Line Items]
Pay Notional	$ 2,040
Receive Notional | €		€ 1,750
Fair Value Gain (Loss) December 31, 2022	(216)
Southern Power
Derivative [Line Items]
Fair Value Gain (Loss) December 31, 2022	(31)		$ 5
Southern Power | Foreign currency derivatives | Cash Flow Hedges of Forecasted Debt
Derivative [Line Items]
Pay Notional	$ 564
Pay Rate	3.78%
Receive Notional | €		500
Receive Rate	1.85%
Southern Power | Foreign currency derivatives | April 2030 | Cash Flow Hedges of Forecasted Debt
Derivative [Line Items]
Fair Value Gain (Loss) December 31, 2022	$ (47)
Southern Company | Foreign currency derivatives | Cash Flow Hedges of Forecasted Debt
Derivative [Line Items]
Fair Value Gain (Loss) December 31, 2022	(169)
Southern Company | Foreign currency derivatives | April 2030 | Fair Value Hedges of Existing Debt
Derivative [Line Items]
Pay Notional	$ 1,476
Pay Rate	3.39%
Receive Notional | €		€ 1,250
Receive Rate	1.88%

DERIVATIVES - Derivative Financ

DERIVATIVES - Derivative Financial Statement Presentation and Amounts With Balance Sheet Offsetting (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	$ 211	$ 238
Derivative asset, gross amount offset	(70)	(25)
Derivative asset, net amounts recognized in the balance sheets	141	213
Derivative liability, gross amounts recognized	728	153
Derivative liability, gross amounts offset	(111)	(28)
Derivative liability, gross amounts recognized in balance sheets	$ 617	$ 125
Derivative asset, statement of financial position, extensible enumeration, not disclosed, flag	Net amounts recognized in the Balance Sheets(b)	Net amounts recognized in the Balance Sheets(b)
Collateral already posted, aggregate fair value	$ 41
Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	15	$ 10
Derivative liability, gross amounts recognized	14	4
Energy-related derivatives | Other deferred charges and assets | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	2	1
Energy-related derivatives | Other deferred credits and liabilities | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	1	0
Energy-related derivatives | Assets from risk management activities | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	13	9
Energy-related derivatives | Other current liabilities | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	13	4
Interest rate derivatives
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized in balance sheets	78
Alabama Power
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amount offset	(24)	(5)
Derivative asset, net amounts recognized in the balance sheets	38	50
Derivative liability, gross amounts offset	(24)	(5)
Derivative liability, gross amounts recognized in balance sheets	15	6
Collateral already posted, aggregate fair value	0
Georgia Power
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	42	75
Derivative asset, gross amount offset	(21)	(8)
Derivative asset, net amounts recognized in the balance sheets	21	67
Derivative liability, gross amounts recognized	62	8
Derivative liability, gross amounts offset	(21)	(8)
Derivative liability, gross amounts recognized in balance sheets	41	0
Georgia Power | Energy-related derivatives | Other deferred charges and assets | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Georgia Power | Energy-related derivatives | Other deferred credits and liabilities | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	1	0
Mississippi Power
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amount offset	(17)	(4)
Derivative asset, net amounts recognized in the balance sheets	42	52
Derivative liability, gross amounts offset	(17)	(4)
Derivative liability, gross amounts recognized in balance sheets	15	1
Southern Power
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, net amounts recognized in the balance sheets	8	4
Derivative liability, gross amounts recognized in balance sheets	59	16
Collateral already posted, aggregate fair value	15
Southern Power | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	3	1
Derivative liability, gross amounts recognized	0	0
Southern Power | Energy-related derivatives | Other current liabilities | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	0	0
Southern Power | Energy-related derivatives | Other current assets | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	2	1
Southern Power | Interest rate derivatives
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized in balance sheets	23
Southern Company Gas
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	28	35
Derivative asset, gross amount offset	0	(8)
Derivative asset, net amounts recognized in the balance sheets	28	27
Derivative liability, gross amounts recognized	151	27
Derivative liability, gross amounts offset	(41)	(11)
Derivative liability, gross amounts recognized in balance sheets	110	16
Collateral already posted, aggregate fair value	41	3
Southern Company Gas | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	12	9
Derivative liability, gross amounts recognized	13	4
Southern Company Gas | Energy-related derivatives | Other deferred charges and assets | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	1	1
Southern Company Gas | Energy-related derivatives | Other deferred credits and liabilities | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	1	0
Southern Company Gas | Energy-related derivatives | Assets from risk management activities | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	11	8
Southern Company Gas | Energy-related derivatives | Other current liabilities | Not Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	12	4
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	175	201
Derivative liability, gross amounts recognized	165	36
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	52	72
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	44	6
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Assets from risk management activities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	123	129
Hedging Instruments for Regulatory Purposes | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	121	30
Hedging Instruments for Regulatory Purposes | Alabama Power | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	62	55
Derivative liability, gross amounts recognized	39	11
Hedging Instruments for Regulatory Purposes | Alabama Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	20	25
Hedging Instruments for Regulatory Purposes | Alabama Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	18	2
Hedging Instruments for Regulatory Purposes | Alabama Power | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	21	9
Hedging Instruments for Regulatory Purposes | Alabama Power | Energy-related derivatives | Other current assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	42	30
Hedging Instruments for Regulatory Purposes | Georgia Power | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	42	75
Derivative liability, gross amounts recognized	61	8
Hedging Instruments for Regulatory Purposes | Georgia Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	6	21
Hedging Instruments for Regulatory Purposes | Georgia Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	18	2
Hedging Instruments for Regulatory Purposes | Georgia Power | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	43	6
Hedging Instruments for Regulatory Purposes | Georgia Power | Energy-related derivatives | Other current assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	36	54
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	59	56
Derivative liability, gross amounts recognized	32	5
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	26	26
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	8	2
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	24	3
Hedging Instruments for Regulatory Purposes | Mississippi Power | Energy-related derivatives | Other current assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	33	30
Hedging Instruments for Regulatory Purposes | Southern Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	1	0
Hedging Instruments for Regulatory Purposes | Southern Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	0	0
Hedging Instruments for Regulatory Purposes | Southern Company Gas | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	1	0
Hedging Instruments for Regulatory Purposes | Southern Company Gas | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	4	0
Hedging Instruments for Regulatory Purposes | Southern Company Gas | Energy-related derivatives | Assets from risk management activities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	12	15
Hedging Instruments for Regulatory Purposes | Southern Company Gas | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	33	12
Cash Flow and Fair Value Hedging | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	21	27
Derivative liability, gross amounts recognized	549	113
Cash Flow and Fair Value Hedging | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	6	1
Cash Flow and Fair Value Hedging | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	4	0
Cash Flow and Fair Value Hedging | Energy-related derivatives | Assets from risk management activities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	3	7
Cash Flow and Fair Value Hedging | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	27	5
Cash Flow and Fair Value Hedging | Interest rate derivatives | Other deferred charges and assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging | Interest rate derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	240	29
Cash Flow and Fair Value Hedging | Interest rate derivatives | Assets from risk management activities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	12	19
Cash Flow and Fair Value Hedging | Interest rate derivatives | Other current liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	62	0
Cash Flow and Fair Value Hedging | Foreign currency derivatives | Other deferred charges and assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging | Foreign currency derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	182	40
Cash Flow and Fair Value Hedging | Foreign currency derivatives | Assets from risk management activities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging | Foreign currency derivatives | Other current liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	34	39
Cash Flow and Fair Value Hedging | Southern Power | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	5	3
Derivative liability, gross amounts recognized	59	16
Cash Flow and Fair Value Hedging | Southern Power | Energy-related derivatives | Other deferred charges and assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	5	1
Cash Flow and Fair Value Hedging | Southern Power | Energy-related derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging | Southern Power | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	12	0
Cash Flow and Fair Value Hedging | Southern Power | Energy-related derivatives | Other current assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	2
Cash Flow and Fair Value Hedging | Southern Power | Foreign currency derivatives | Other deferred charges and assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging | Southern Power | Foreign currency derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	36	0
Cash Flow and Fair Value Hedging | Southern Power | Foreign currency derivatives | Other current liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	11	16
Cash Flow and Fair Value Hedging | Southern Power | Foreign currency derivatives | Other current assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging | Southern Company Gas | Energy-related derivatives | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	4	11
Derivative liability, gross amounts recognized	105	11
Cash Flow and Fair Value Hedging | Southern Company Gas | Energy-related derivatives | Assets from risk management activities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	3	5
Cash Flow and Fair Value Hedging | Southern Company Gas | Energy-related derivatives | Other current liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	15	5
Cash Flow and Fair Value Hedging | Southern Company Gas | Interest rate derivatives | Other deferred charges and assets | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	0
Cash Flow and Fair Value Hedging | Southern Company Gas | Interest rate derivatives | Other deferred credits and liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	72	6
Cash Flow and Fair Value Hedging | Southern Company Gas | Interest rate derivatives | Assets from risk management activities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative asset, gross amounts recognized	0	6
Cash Flow and Fair Value Hedging | Southern Company Gas | Interest rate derivatives | Other current liabilities | Designated as Hedging Instrument
Fair value of energy-related derivatives and interest rate derivatives
Derivative liability, gross amounts recognized	$ 14	$ 0

DERIVATIVES - Schedule of Unrea

DERIVATIVES - Schedule of Unrealized Gain (Loss) Recognized in the Balance Sheet (Details) - Energy-related derivatives - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	$ 9	$ 155
Other regulatory assets, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(71)	(17)
Other regulatory assets, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(23)
Other regulatory liabilities, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	72	107
Other regulatory liabilities, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	31	65
Alabama Power
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	23	44
Alabama Power | Other regulatory assets, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(8)	(6)
Alabama Power | Other regulatory assets, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(7)
Alabama Power | Other regulatory liabilities, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	29	28
Alabama Power | Other regulatory liabilities, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	9	22
Georgia Power
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(19)	67
Georgia Power | Other regulatory assets, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(26)	0
Georgia Power | Other regulatory assets, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(14)
Georgia Power | Other regulatory liabilities, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	19	48
Georgia Power | Other regulatory liabilities, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	2	19
Mississippi Power
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	27	51
Mississippi Power | Other regulatory assets, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(13)	0
Mississippi Power | Other regulatory assets, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(2)
Mississippi Power | Other regulatory liabilities, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	22	27
Mississippi Power | Other regulatory liabilities, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	20	24
Southern Company Gas
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(22)	(7)
Southern Company Gas | Other regulatory assets, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	(24)	(11)
Southern Company Gas | Other regulatory assets, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	0
Southern Company Gas | Other regulatory liabilities, current
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	2	4
Southern Company Gas | Other regulatory liabilities, deferred
Derivatives, Fair Value [Line Items]
Total energy-related derivative gains (losses)	$ 0	$ 0

DERIVATIVES - Pre-Tax Effects o

DERIVATIVES - Pre-Tax Effects of Derivatives Designated as Hedges on AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	$ (80)	$ (67)	$ 14
Energy-related derivatives | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	3	34	(8)
Interest rate derivatives | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	46	5	(26)
Foreign currency derivatives | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	(105)	(103)	48
Foreign currency derivatives | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	(24)	(3)	0
Georgia Power | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	31	0	(3)
Southern Power
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	(120)	(91)	46
Southern Power | Energy-related derivatives | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	(15)	12	(2)
Southern Power | Foreign currency derivatives | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	(105)	(103)	48
Southern Company Gas
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	18	22	(29)
Southern Company Gas | Energy-related derivatives | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	18	22	(6)
Southern Company Gas | Interest rate derivatives | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) From Derivatives Recognized in OCI	$ 0	$ 0	$ (23)

DERIVATIVES - Pre-Tax Effects_2

DERIVATIVES - Pre-Tax Effects of Derivatives Designated as Hedges on Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Depreciation and amortization	$ 3,663	$ 3,565	$ 3,518
Interest expense, net of amounts capitalized	(2,022)	(1,837)	(1,821)
Other income (expense), net	500	456	336
Energy-related derivatives | Cost of Sales | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	37	17	(8)
Energy-related derivatives | Depreciation and Amortization | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(5)	9	(3)
Interest rate derivatives | Interest Expense | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(25)	(27)	(26)
Interest rate derivatives | Interest Expense | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(291)	(30)	27
Foreign currency derivatives | Interest Expense | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(19)	(24)	(23)
Foreign currency derivatives | Other Income (Expense) | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(83)	(104)	114
Gain (loss) on foreign currency fair value hedges	(106)	(63)	0
Amount excluded from effectiveness testing recognized in earnings	24	3	0
Southern Power
Derivative Instruments, Gain (Loss) [Line Items]
Depreciation and amortization	516	517	494
Interest expense, net of amounts capitalized	(138)	(147)	(151)
Other income (expense), net	7	10	19
Southern Power | Energy-related derivatives | Depreciation and Amortization | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(5)	9	(3)
Southern Power | Foreign currency derivatives | Interest Expense | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(19)	(24)	(23)
Southern Power | Foreign currency derivatives | Other Income (Expense) | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	(83)	(104)	114
Southern Company Gas
Derivative Instruments, Gain (Loss) [Line Items]
Cost of sales	3,004	1,619	972
Depreciation and amortization	559	536	500
Interest expense, net of amounts capitalized	(263)	(238)	(231)
Other income (expense), net	53	(53)	41
Southern Company Gas | Interest rate derivatives | Interest Expense | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on hedges	(4)	0	0
Southern Company Gas | Interest rate derivatives | Interest Expense | Fair Value Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on hedges	(86)	0	0
Southern Company Gas | Foreign currency derivatives | Other Income (Expense) | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative	$ 37	$ 17	$ (8)

DERIVATIVES - Cumulative Basis

DERIVATIVES - Cumulative Basis Adjustments for Fair Value Hedges (Details) - Long-term debt - Fair Value Hedging - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Carrying Amount of the Hedged Item	$ (2,927)	$ (3,280)
Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item	282	9
Southern Company Gas
Derivative Instruments, Gain (Loss) [Line Items]
Carrying Amount of the Hedged Item	(415)	(493)
Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item	$ 81	$ 2

DERIVATIVES - Pre-Tax Effects_3

DERIVATIVES - Pre-Tax Effects of Derivatives Not Designated as Hedging (Details) - USD ($)	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Energy-related derivatives | Natural gas revenues
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	$ (11,000,000)	$ (117,000,000)	$ 134,000,000
Energy-related derivatives | Cost of natural gas
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	(65,000,000)	(27,000,000)	15,000,000
Energy-related derivatives | Cost of natural gas | Not Designated as Hedging Instrument | Southern Company Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	(76,000,000)	(144,000,000)	149,000,000
Weather derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	$ 7,000,000	$ 0	$ 9,000,000

ACQUISITIONS AND DISPOSITIONS -

ACQUISITIONS AND DISPOSITIONS - Southern Company Narrative (Details)	1 Months Ended		3 Months Ended			12 Months Ended
	Dec. 31, 2021 USD ($) project	Oct. 31, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2022 USD ($) project	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Business Acquisition [Line Items]
Lease, initial impairment loss				$ 34,000,000
Lease, initial impairment loss, after tax				17,000,000
Lease, impairment loss					$ 154,000,000	$ 0	$ 7,000,000	$ 206,000,000
Lease, impairment loss, after tax					$ 74,000,000
Proceeds from sale of assets subject to leveraged lease	$ 673,000,000	$ 45,000,000
Gain (loss) on sale of assets subject to leveraged lease		0
Leveraged leases, income tax benefits		$ 16,000,000
Number of international projects subject to leveraged lease terminated | project	2					2
Gain (loss) on termination of leveraged leases	$ 93,000,000
Gain (loss) on termination of leveraged leases, after tax	$ 99,000,000
All Other
Business Acquisition [Line Items]
Lease, impairment loss			$ 7,000,000	18,000,000			7,000,000	206,000,000
Lease, impairment loss, after tax			$ 6,000,000	$ 14,000,000			$ 6,000,000	$ 105,000,000

ACQUISITIONS AND DISPOSITIONS_2

ACQUISITIONS AND DISPOSITIONS - Alabama Power Narrative (Details) $ in Millions		12 Months Ended
	Sep. 30, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($) MW	Aug. 31, 2020 USD ($)
Business Acquisition [Line Items]
Capital expenditures related to qualifying projects		$ 7,923	$ 7,586	$ 7,522
Alabama Power
Business Acquisition [Line Items]
Capital expenditures related to qualifying projects		$ 2,016	$ 1,753	$ 1,970
Alabama Power | Calhoun Generating Station
Business Acquisition [Line Items]
Purchase price	$ 179
Capital expenditures related to qualifying projects	$ 171
Alabama Power | Central Alabama Generating Station
Business Acquisition [Line Items]
Approximate nameplate capacity (in MWs) | MW				885
Purchase price					$ 461
Property, plant, and equipment					$ 452

ACQUISITIONS AND DISPOSITIONS_3

ACQUISITIONS AND DISPOSITIONS - Schedule of Asset Acquisitions (Details) - Southern Power - MW	1 Months Ended
	Feb. 28, 2021	May 31, 2020
Deuel Harvest
Asset Acquisition [Line Items]
Approximate Nameplate Capacity (MW)	300
Deuel Harvest | Maximum
Asset Acquisition [Line Items]
PPA Contract Period	25 years
Deuel Harvest | Minimum
Asset Acquisition [Line Items]
PPA Contract Period	15 years
Beech Ridge II(b)
Asset Acquisition [Line Items]
Approximate Nameplate Capacity (MW)		56
PPA Contract Period		12 years
Deuel Harvest | Deuel Harvest
Asset Acquisition [Line Items]
Ownership Percentage	100%
Beech Ridge II(b) | Beech Ridge II(b)
Asset Acquisition [Line Items]
Ownership Percentage		100%

ACQUISITIONS AND DISPOSITIONS_4

ACQUISITIONS AND DISPOSITIONS - Southern Power Narrative (Details) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2020 USD ($)	Dec. 31, 2022 USD ($) MW	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 MW
Asset Acquisition [Line Items]
Construction work in progress		$ 10,896	$ 8,771
Gain (loss) on dispositions		42	176	$ 66
Southern Power
Asset Acquisition [Line Items]
Construction work in progress		41	45
Gain (loss) on dispositions		$ 2	$ 41	$ 39
Southern Power | Garland
Asset Acquisition [Line Items]
Nameplate capacity placed in service (in MWs) | MW		15
Southern Power | Tranquility Solar Storage
Asset Acquisition [Line Items]
Nameplate capacity placed in service (in MWs) | MW		40
Wind Generating Facility | Southern Power
Asset Acquisition [Line Items]
Gain (loss) on dispositions		$ 37
Gain (loss) on dispositions, after tax		$ 28
Disposal Group, Disposed of by Sale, Not Discontinued Operations | Mankato | Southern Power
Asset Acquisition [Line Items]
Gain (loss) on dispositions	$ 39
Approximate nameplate capacity (in MWs) | MW					385
Consideration for sale	663
Gain (loss) on dispositions, after tax	$ 23

ACQUISITIONS AND DISPOSITIONS_5

ACQUISITIONS AND DISPOSITIONS - Schedule of Construction Projects (Details) - Southern Power $ in Millions	1 Months Ended						5 Months Ended	6 Months Ended	12 Months Ended
	Feb. 28, 2022 MW	Nov. 30, 2021 MW	Dec. 31, 2020	Nov. 30, 2020 USD ($) MW	Jun. 30, 2020 USD ($)	May 31, 2020 MW	Mar. 31, 2022 MW	Feb. 28, 2022 MW	Dec. 31, 2021 MW	Dec. 31, 2022
Tranquility Solar Storage
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)							72
Nameplate capacity placed in service (in MWs)		32
Garland Solar Storage
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)							72	88
PPA Contract Period							20 years	20 years
Nameplate capacity placed in service (in MWs)	15								73
Glass Sands
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)		118
PPA Contract Period		12 years
Skookumchuck
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)				136
PPA Contract Period				20 years
Reading
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)						200
PPA Contract Period						12 years
Tranquillity Solar Storage
Business Acquisition [Line Items]
Nameplate capacity placed in service (in MWs)									40
Tranquility Solar Storage | Class B Membership Interest | Tranquility Solar Storage
Business Acquisition [Line Items]
Noncontrolling ownership percentage sold by parent			100%
Garland Solar Storage | Class B Membership Interest | Garland Solar Storage
Business Acquisition [Line Items]
Noncontrolling ownership percentage sold by parent			100%
Glass Sands | Glass Sands
Business Acquisition [Line Items]
Noncontrolling ownership percentage held by parent									100%
Skookumchuck | Skookumchuck
Business Acquisition [Line Items]
Proceeds from tax equity transaction | $				$ 121
Skookumchuck | Class B Membership Interest | Skookumchuck
Business Acquisition [Line Items]
Noncontrolling ownership percentage held by parent				100%
Reading | Reading
Business Acquisition [Line Items]
Proceeds from tax equity transaction | $					$ 156
Reading | Class B Membership Interest | Reading
Business Acquisition [Line Items]
Noncontrolling ownership percentage held by parent										100%

ACQUISITIONS AND DISPOSITIONS_6

ACQUISITIONS AND DISPOSITIONS - GAS Acquisitions and Dispositions Narrative (Details) $ in Millions

1 Months Ended

3 Months Ended

6 Months Ended

12 Months Ended

Jul. 01, 2021 USD ($)

Jul. 31, 2021 USD ($)

Dec. 31, 2020 USD ($)

Mar. 31, 2020 USD ($) payment

Dec. 31, 2022 USD ($)

Dec. 31, 2021 USD ($)

Dec. 31, 2021 USD ($)

Dec. 31, 2022 USD ($)

Dec. 31, 2021 USD ($)

Dec. 31, 2020 USD ($)

Sep. 07, 2022 USD ($) storageFacility

May 31, 2022 USD ($)

Apr. 22, 2021 USD ($)

Business Acquisition [Line Items]

Gain (loss) on dispositions

$ 42

$ 176

$ 66

Southern Company Gas

Business Acquisition [Line Items]

Gain (loss) on dispositions

4

$ 127

$ 22

Disposal Group, Disposed of by Sale, Not Discontinued Operations | Sequent | Southern Company Gas

Business Acquisition [Line Items]

Consideration for sale

$ 159

Gain (loss) on dispositions

121

121

Gain (loss) on dispositions, after tax

$ 92

92

Deferred tax expense, increase from change in appointment rate

$ 85

$ 85

$ 85

$ 85

Disposal Group, Disposed of by Sale, Not Discontinued Operations | Pivotal LNG | Southern Company Gas

Business Acquisition [Line Items]

Cash proceeds from sale of business

$ 178

Number of contingent milestone payments | payment

2

Contingent milestone payment, amount

$ 5

$ 5

Disposal Group, Disposed of by Sale, Not Discontinued Operations | Jefferson Island | Southern Company Gas | Natural Gas Storage Facility

Business Acquisition [Line Items]

Gain (loss) on dispositions

$ 22

Gain (loss) on dispositions, after tax

16

Cash proceeds from sale of business

$ 33

Disposal Group, Disposed of by Sale, Not Discontinued Operations | Natural Gas Storage Facilities | Southern Company Gas

Business Acquisition [Line Items]

Consideration for sale

$ 186

Gain (loss) on dispositions

$ (131)

Gain (loss) on dispositions, after tax

$ (99)

Number of natural gas storage facilities sold | storageFacility

2

SEGMENT AND RELATED INFORMATI_3

SEGMENT AND RELATED INFORMATION - Narrative (Details) $ in Millions	12 Months Ended
	Dec. 31, 2022 USD ($) state segment	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2014
Segment Reporting Information [Line Items]
Total operating revenues	$ 25,941	$ 23,463	$ 21,097
Southern Power
Segment Reporting Information [Line Items]
Total operating revenues	2,805	1,605	1,119
Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues	$ 5,905	6,293	5,039
Number of reportable segments | segment	3
Number of states in which entity operates | state	4
Southern Company Gas | Southern Power
Segment Reporting Information [Line Items]
Total operating revenues		18	26
Southern Natural Gas Company, LLC | Southern Company Gas
Segment Reporting Information [Line Items]
Ownership percentage, equity method investment	50%
Dalton Pipeline | Southern Company Gas
Segment Reporting Information [Line Items]
Ownership percentage, equity method investment	50%
PennEast Pipeline | Southern Company Gas
Segment Reporting Information [Line Items]
Ownership percentage, equity method investment	20%			20%
Atlantic Coast Pipeline | Southern Company Gas
Segment Reporting Information [Line Items]
Ownership percentage, equity method investment	5%
Wholesale revenues, affiliates | Southern Power | Traditional Electric Operating Companies
Segment Reporting Information [Line Items]
Total operating revenues	$ 875	$ 515	$ 364

SEGMENT AND RELATED INFORMATI_4

SEGMENT AND RELATED INFORMATION - Financial Data for Business Segments (Details) $ in Millions		1 Months Ended			3 Months Ended					6 Months Ended		12 Months Ended
	Jul. 01, 2021 USD ($)	Dec. 31, 2021 USD ($) project	Jul. 31, 2021 USD ($)	Jan. 31, 2020 USD ($)	Dec. 31, 2022 USD ($)	Sep. 30, 2021 USD ($)	Jun. 30, 2021 USD ($)	Dec. 31, 2020 USD ($)	Jun. 30, 2020 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2022 USD ($) project	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Segment Reporting Information [Line Items]
Total operating revenues												$ 29,279	$ 23,113	$ 20,375
Depreciation and amortization												3,663	3,565	3,518
Operating income (loss)												5,370	3,698	4,885
Interest income												59	22	37
Earnings from equity method investments												151	76	153
Interest expense												2,022	1,837	1,821
Income taxes (benefit)												795	267	393
Segment net income (loss)												3,524	2,393	3,119
Goodwill		$ 5,280			$ 5,161			$ 5,280		$ 5,280	$ 5,280	5,161	5,280	5,280
Total assets		127,534			134,891			122,935		127,534	127,534	134,891	127,534	122,935
Segment and Related Information (Textual) [Abstract]
Estimated loss on Plant Vogtle Units 3 and 4												183	1,692	325
Gain (loss) on dispositions												42	176	66
Impairment charges												$ 251	2	0
Gain (loss) on termination of leveraged leases		93
Gain (loss) on termination of leveraged leases, after tax		$ 99
Number of international projects subject to leveraged lease terminated | project		2										2
Lease, impairment loss									$ 154			$ 0	7	206
Lease, impairment loss, after tax									$ 74
Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues												5,962	4,380	3,434
All Other
Segment and Related Information (Textual) [Abstract]
Lease, impairment loss							$ 7	18					7	206
Lease, impairment loss, after tax							6	14					6	105
Operating Segments | Electric Utilities
Segment Reporting Information [Line Items]
Total operating revenues												22,873	18,300	16,497
Depreciation and amortization												3,029	2,953	2,941
Interest income												47	21	30
Earnings from equity method investments												0	1	0
Interest expense												1,067	968	976
Income taxes (benefit)												848	219	517
Segment net income (loss)												3,672	2,247	3,115
Goodwill		$ 2			2			2		2	2	2	2	2
Total assets		101,774			108,283			98,041		101,774	101,774	108,283	101,774	98,041
Operating Segments | Traditional Electric Operating Companies
Segment Reporting Information [Line Items]
Total operating revenues												20,408	16,614	15,135
Depreciation and amortization												2,513	2,436	2,447
Interest income												44	20	26
Earnings from equity method investments												0	1	0
Interest expense												929	821	825
Income taxes (benefit)												828	232	514
Segment net income (loss)												3,318	1,981	2,877
Goodwill		0			0			0		0	0	0	0	0
Total assets		89,051			95,861			85,486		89,051	89,051	95,861	89,051	85,486
Operating Segments | Southern Power
Segment Reporting Information [Line Items]
Total operating revenues												3,369	2,216	1,733
Depreciation and amortization												516	517	494
Interest income												3	1	4
Earnings from equity method investments												0	0	0
Interest expense												138	147	151
Income taxes (benefit)												20	(13)	3
Segment net income (loss)												354	266	238
Goodwill		2			2			2		2	2	2	2	2
Total assets		13,390			13,081			13,235		13,390	13,390	13,081	13,390	13,235
Operating Segments | Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues												5,962	4,380	3,434
Depreciation and amortization												559	536	500
Interest income												3	0	5
Earnings from equity method investments												148	50	141
Interest expense												263	238	231
Income taxes (benefit)												180	275	173
Segment net income (loss)												572	539	590
Goodwill		5,015			5,015			5,015		5,015	5,015	5,015	5,015	5,015
Total assets		23,560			24,621			22,630		23,560	23,560	24,621	23,560	22,630
Operating Segments | All Other
Segment Reporting Information [Line Items]
Total operating revenues												593	582	596
Depreciation and amortization												75	76	77
Interest income												16	4	6
Earnings from equity method investments												3	24	12
Interest expense												694	631	614
Income taxes (benefit)												(233)	(227)	(297)
Segment net income (loss)												(711)	(384)	(592)
Goodwill		263			144			263		263	263	144	263	263
Total assets		2,975			2,665			3,168		2,975	2,975	2,665	2,975	3,168
Intersegment Eliminations
Segment Reporting Information [Line Items]
Total operating revenues												(149)	(149)	(152)
Depreciation and amortization												0	0	0
Interest income												(7)	(3)	(4)
Earnings from equity method investments												0	1	0
Interest expense												(2)	0	0
Income taxes (benefit)												0	0	0
Segment net income (loss)												(9)	(9)	6
Goodwill		0			0			0		0	0	0	0	0
Total assets		(775)			(678)			(904)		(775)	(775)	(678)	(775)	(904)
Intersegment Eliminations | Electric Utilities
Segment Reporting Information [Line Items]
Total operating revenues												(904)	(530)	(371)
Depreciation and amortization												0	0	0
Interest income												0	0	0
Earnings from equity method investments												0	0	0
Interest expense												0	0	0
Income taxes (benefit)												0	0	0
Segment net income (loss)												0	0	0
Goodwill		0			0			0		0	0	0	0	0
Total assets		(667)			(659)			(680)		(667)	(667)	(659)	(667)	(680)
Georgia Power
Segment Reporting Information [Line Items]
Total operating revenues												11,584	9,260	8,309
Depreciation and amortization												1,430	1,371	1,425
Operating income (loss)												2,352	568	1,972
Interest expense												485	421	425
Income taxes (benefit)												370	(168)	152
Total assets		48,461			53,163					48,461	48,461	53,163	48,461
Segment and Related Information (Textual) [Abstract]
Estimated loss on Plant Vogtle Units 3 and 4												183	1,692	325
Georgia Power | Traditional Electric Operating Companies | Plant Vogtle Units 3 and 4
Segment and Related Information (Textual) [Abstract]
Estimated loss on Plant Vogtle Units 3 and 4												183	1,700
Estimated loss on Plant Vogtle Units 3 and 4, net of tax												137	1,300	242
Southern Power
Segment Reporting Information [Line Items]
Total operating revenues												3,369	2,216	1,733
Depreciation and amortization												516	517	494
Operating income (loss)												398	291	342
Interest expense												138	147	151
Income taxes (benefit)												20	(13)	3
Total assets		13,390			13,081					13,390	13,390	13,081	13,390
Segment and Related Information (Textual) [Abstract]
Gain (loss) on dispositions												2	41	39
Southern Power | Wind Generating Facility
Segment and Related Information (Textual) [Abstract]
Gain (loss) on dispositions												37
Gain (loss) on dispositions, after tax												28
Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues												5,962	4,380	3,434
Depreciation and amortization												559	536	500
Operating income (loss)												814	1,055	812
Earnings from equity method investments												148	50	141
Interest expense												263	238	231
Income taxes (benefit)												180	275	173
Segment net income (loss)												572	539	590
Goodwill		5,015			5,015					5,015	5,015	5,015	5,015
Total assets		23,560			24,621			22,630		23,560	23,560	24,621	23,560	22,630
Segment and Related Information (Textual) [Abstract]
Gain (loss) on dispositions												4	127	22
Impairment charges												131	0	0
Southern Company Gas | PennEast Pipeline
Segment Reporting Information [Line Items]
Earnings from equity method investments												0	(81)	7
Income taxes (benefit)													7
Segment and Related Information (Textual) [Abstract]
Impairment charges						$ 2	82					84	84
Impairment charges, after tax						$ 2	$ 58					67	67
Southern Company Gas | Operating Segments
Segment Reporting Information [Line Items]
Total operating revenues												5,937	4,374	3,466
Depreciation and amortization												537	505	470
Operating income (loss)												957	1,095	814
Earnings from equity method investments												148	50	141
Interest expense												259	237	228
Income taxes (benefit)												217	213	178
Segment net income (loss)												671	626	592
Total assets		23,971			25,233			23,040		23,971	23,971	25,233	23,971	23,040
Southern Company Gas | Operating Segments | All Other
Segment Reporting Information [Line Items]
Total operating revenues												55	38	36
Depreciation and amortization												22	31	30
Operating income (loss)												(135)	(40)	(7)
Earnings from equity method investments												0	0	0
Interest expense												4	1	3
Income taxes (benefit)												(37)	62	(5)
Segment net income (loss)												(99)	(87)	(2)
Total assets		12,114			8,943			11,336		12,114	12,114	8,943	12,114	11,336
Southern Company Gas | Intersegment Eliminations
Segment Reporting Information [Line Items]
Total operating revenues												(30)	(32)	(68)
Depreciation and amortization												0	0	0
Operating income (loss)												(8)	0	5
Earnings from equity method investments												0	0	0
Interest expense												0	0	0
Income taxes (benefit)												0	0	0
Segment net income (loss)												0	0	0
Total assets		$ (12,525)			(9,555)			$ (11,746)		(12,525)	(12,525)	(9,555)	$ (12,525)	(11,746)
Sequent | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Southern Company Gas
Segment and Related Information (Textual) [Abstract]
Gain (loss) on dispositions	$ 121											121
Gain (loss) on dispositions, after tax	$ 92											92
Deferred tax expense, increase from change in appointment rate			$ 85							$ 85	$ 85	$ 85
Mankato | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Southern Power
Segment and Related Information (Textual) [Abstract]
Gain (loss) on dispositions				$ 39
Gain (loss) on dispositions, after tax				$ 23
Gain on sale														39
Gain on sale, after tax														$ 23
Natural Gas Storage Facilities | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Southern Company Gas
Segment and Related Information (Textual) [Abstract]
Gain (loss) on dispositions					(131)
Gain (loss) on dispositions, after tax					$ (99)

SEGMENT AND RELATED INFORMATI_5

SEGMENT AND RELATED INFORMATION - Electric Utilities' Revenues (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Revenue from External Customer [Line Items]
Total operating revenues	$ 29,279	$ 23,113	$ 20,375
Wholesale electric revenues
Revenue from External Customer [Line Items]
Total operating revenues	3,641	2,455	1,945
Electric Utilities
Revenue from External Customer [Line Items]
Total operating revenues	22,873	18,300	16,497
Electric Utilities | Retail electric revenues
Revenue from External Customer [Line Items]
Total operating revenues	18,197	14,852	13,643
Electric Utilities | Wholesale electric revenues
Revenue from External Customer [Line Items]
Total operating revenues	3,641	2,455	1,945
Electric Utilities | Other
Revenue from External Customer [Line Items]
Total operating revenues	$ 1,035	$ 993	$ 909

SEGMENT AND RELATED INFORMATI_6

SEGMENT AND RELATED INFORMATION - Gas Revenues (Details) - USD ($) $ in Millions		1 Months Ended		3 Months Ended		6 Months Ended		12 Months Ended
	Jul. 01, 2021	Jul. 31, 2021	Dec. 31, 2020	Sep. 30, 2021	Jun. 30, 2021	Dec. 31, 2021	Dec. 31, 2021	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Segment Reporting Information [Line Items]
Total operating revenues								$ 29,279	$ 23,113	$ 20,375
Impairment charges								251	2	0
Gain on dispositions, net								42	176	66
Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues								5,962	4,380	3,434
Impairment charges								131	0	0
Gain on dispositions, net								4	127	22
Southern Company Gas | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Sequent
Segment Reporting Information [Line Items]
Gain on dispositions, net	$ 121							121
Gain (loss) on dispositions, after tax	$ 92							92
Deferred tax expense, increase from change in appointment rate		$ 85				$ 85	$ 85	85
Southern Company Gas | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Jefferson Island | Natural Gas Storage Facility
Segment Reporting Information [Line Items]
Gain on dispositions, net			$ 22
Gain (loss) on dispositions, after tax			$ 16
Southern Company Gas | PennEast Pipeline
Segment Reporting Information [Line Items]
Impairment charges				$ 2	$ 82			84	84
Impairment charges, after tax				$ 2	$ 58			67	67
Operating Segments | Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues								5,937	4,374	3,466
Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues								5,962	4,380	3,434
Southern Company Gas | Gas distribution operations
Segment Reporting Information [Line Items]
Total operating revenues								5,240	3,656	2,902
Southern Company Gas | Gas marketing services
Segment Reporting Information [Line Items]
Total operating revenues								638	475	408
Southern Company Gas | Other Gas Revenue
Segment Reporting Information [Line Items]
Total operating revenues								84	249	124
Southern Company Gas | Operating Segments
Segment Reporting Information [Line Items]
Total operating revenues								5,962	4,380	3,434
Wholesale gas services | Operating Segments | Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues								$ 0	188	74
Less Gross Gas Costs									3,783	4,585
Wholesale gas services | Operating Segments | Third Party Gross Revenues | Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues									3,881	4,544
Wholesale gas services | Operating Segments | Intercompany Revenues | Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues									90	115
Wholesale gas services | Operating Segments | Total Gross Revenues | Southern Company Gas
Segment Reporting Information [Line Items]
Total operating revenues									$ 3,971	$ 4,659

VALUATION AND QUALIFYING ACCO_2

VALUATION AND QUALIFYING ACCOUNTS (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Provision for uncollectible accounts:
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 78	$ 118	$ 49
Charged to Income	71	51	78
Charged to Other Accounts	(1)	(23)	27
Deductions	77	68	36
Balance at End of Period	71	78	118
Provision for uncollectible accounts: | Alabama Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	14	43	22
Charged to Income	10	(7)	25
Charged to Other Accounts	0	0	0
Deductions	10	22	4
Balance at End of Period	14	14	43
Provision for uncollectible accounts: | Georgia Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	2	26	2
Charged to Income	21	16	14
Charged to Other Accounts	0	(23)	23
Deductions	20	17	13
Balance at End of Period	3	2	26
Provision for uncollectible accounts: | Mississippi Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	1	1	1
Charged to Income	1	1	1
Charged to Other Accounts	1	0	0
Deductions	2	1	1
Balance at End of Period	1	1	1
Provision for uncollectible accounts: | Southern Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	5	0	0
Charged to Income	(2)	5	0
Charged to Other Accounts	0	0	0
Deductions	2	0	0
Balance at End of Period	1	5	0
Provision for uncollectible accounts: | Southern Company Gas
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	39	40	18
Charged to Income	55	26	35
Charged to Other Accounts	0	0	4
Deductions	44	27	17
Balance at End of Period	50	39	40
Tax valuation allowance (net state)
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	169	112	113
Charged to Income	68	57	0
Charged to Other Accounts	(30)	0	0
Deductions	0	0	1
Balance at End of Period	207	169	112
Tax valuation allowance (net state) | Georgia Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	58	28	28
Charged to Income	70	30	0
Charged to Other Accounts	(30)	0	0
Deductions	0	0	0
Balance at End of Period	98	58	28
Tax valuation allowance (net state) | Mississippi Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	32	32	32
Charged to Income	0	0	0
Charged to Other Accounts	0	0	0
Deductions	0	0	0
Balance at End of Period	32	32	32
Tax valuation allowance (net state) | Southern Power
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	21	27	29
Charged to Income	0	(6)	(1)
Charged to Other Accounts	0	0	0
Deductions	0	0	1
Balance at End of Period	21	21	27
Tax valuation allowance (net state) | Southern Company Gas
SEC Schedule, 12-09, Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	7	4	4
Charged to Income	0	3	0
Charged to Other Accounts	0	0	0
Deductions	0	0	0
Balance at End of Period	$ 7	$ 7	$ 4

Uncategorized Items - so-202212

Label	Element	Value
Operating Segments [Member] | Southern Company Gas [Member] | Gas Distribution Operations [Member]
Income Tax Expense (Benefit)	us-gaap_IncomeTaxExpenseBenefit	$ 120,000,000
Income Tax Expense (Benefit)	us-gaap_IncomeTaxExpenseBenefit	145,000,000
Income Tax Expense (Benefit)	us-gaap_IncomeTaxExpenseBenefit	114,000,000
Operating Income (Loss)	us-gaap_OperatingIncomeLoss	655,000,000
Operating Income (Loss)	us-gaap_OperatingIncomeLoss	708,000,000
Operating Income (Loss)	us-gaap_OperatingIncomeLoss	803,000,000
Depreciation and Amortization Excluding Nuclear Fuel	so_DepreciationAndAmortizationExcludingNuclearFuel	482,000,000
Depreciation and Amortization Excluding Nuclear Fuel	so_DepreciationAndAmortizationExcludingNuclearFuel	442,000,000
Depreciation and Amortization Excluding Nuclear Fuel	so_DepreciationAndAmortizationExcludingNuclearFuel	516,000,000
Assets	us-gaap_Assets	22,040,000,000
Assets	us-gaap_Assets	20,917,000,000
Assets	us-gaap_Assets	19,090,000,000
Income (Loss) from Equity Method Investments	us-gaap_IncomeLossFromEquityMethodInvestments	0
Income (Loss) from Equity Method Investments	us-gaap_IncomeLossFromEquityMethodInvestments	0
Income (Loss) from Equity Method Investments	us-gaap_IncomeLossFromEquityMethodInvestments	0
Net Income (Loss) Available to Common Stockholders, Basic	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic	412,000,000
Net Income (Loss) Available to Common Stockholders, Basic	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic	390,000,000
Net Income (Loss) Available to Common Stockholders, Basic	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic	470,000,000
Revenues	us-gaap_Revenues	3,679,000,000
Revenues	us-gaap_Revenues	2,952,000,000
Revenues	us-gaap_Revenues	5,267,000,000
Interest and Debt Expense	us-gaap_InterestAndDebtExpense	207,000,000
Interest and Debt Expense	us-gaap_InterestAndDebtExpense	229,000,000
Interest and Debt Expense	us-gaap_InterestAndDebtExpense	192,000,000
Operating Segments [Member] | Southern Company Gas [Member] | Gas Marketing Services [Member]
Income Tax Expense (Benefit)	us-gaap_IncomeTaxExpenseBenefit	34,000,000
Income Tax Expense (Benefit)	us-gaap_IncomeTaxExpenseBenefit	37,000,000
Income Tax Expense (Benefit)	us-gaap_IncomeTaxExpenseBenefit	28,000,000
Operating Income (Loss)	us-gaap_OperatingIncomeLoss	133,000,000
Operating Income (Loss)	us-gaap_OperatingIncomeLoss	119,000,000
Operating Income (Loss)	us-gaap_OperatingIncomeLoss	125,000,000
Depreciation and Amortization Excluding Nuclear Fuel	so_DepreciationAndAmortizationExcludingNuclearFuel	18,000,000
Depreciation and Amortization Excluding Nuclear Fuel	so_DepreciationAndAmortizationExcludingNuclearFuel	22,000,000
Depreciation and Amortization Excluding Nuclear Fuel	so_DepreciationAndAmortizationExcludingNuclearFuel	16,000,000
Assets	us-gaap_Assets	1,556,000,000
Assets	us-gaap_Assets	1,503,000,000
Assets	us-gaap_Assets	1,616,000,000
Income (Loss) from Equity Method Investments	us-gaap_IncomeLossFromEquityMethodInvestments	0
Income (Loss) from Equity Method Investments	us-gaap_IncomeLossFromEquityMethodInvestments	0
Income (Loss) from Equity Method Investments	us-gaap_IncomeLossFromEquityMethodInvestments	0
Net Income (Loss) Available to Common Stockholders, Basic	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic	88,000,000
Net Income (Loss) Available to Common Stockholders, Basic	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic	89,000,000
Net Income (Loss) Available to Common Stockholders, Basic	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic	94,000,000
Revenues	us-gaap_Revenues	638,000,000
Revenues	us-gaap_Revenues	475,000,000
Revenues	us-gaap_Revenues	408,000,000
Interest and Debt Expense	us-gaap_InterestAndDebtExpense	3,000,000
Interest and Debt Expense	us-gaap_InterestAndDebtExpense	3,000,000
Interest and Debt Expense	us-gaap_InterestAndDebtExpense	3,000,000
Operating Segments [Member] | Southern Company Gas [Member] | Wholesale Gas Services [Member]
Income Tax Expense (Benefit)	us-gaap_IncomeTaxExpenseBenefit	32,000,000
Income Tax Expense (Benefit)	us-gaap_IncomeTaxExpenseBenefit	0
Income Tax Expense (Benefit)	us-gaap_IncomeTaxExpenseBenefit	3,000,000
Operating Income (Loss)	us-gaap_OperatingIncomeLoss	20,000,000
Operating Income (Loss)	us-gaap_OperatingIncomeLoss	241,000,000
Operating Income (Loss)	us-gaap_OperatingIncomeLoss	0
Depreciation and Amortization Excluding Nuclear Fuel	so_DepreciationAndAmortizationExcludingNuclearFuel	0
Depreciation and Amortization Excluding Nuclear Fuel	so_DepreciationAndAmortizationExcludingNuclearFuel	1,000,000
Depreciation and Amortization Excluding Nuclear Fuel	so_DepreciationAndAmortizationExcludingNuclearFuel	0
Assets	us-gaap_Assets	850,000,000
Assets	us-gaap_Assets	0
Assets	us-gaap_Assets	31,000,000
Income (Loss) from Equity Method Investments	us-gaap_IncomeLossFromEquityMethodInvestments	0
Income (Loss) from Equity Method Investments	us-gaap_IncomeLossFromEquityMethodInvestments	0
Income (Loss) from Equity Method Investments	us-gaap_IncomeLossFromEquityMethodInvestments	0
Net Income (Loss) Available to Common Stockholders, Basic	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic	107,000,000
Net Income (Loss) Available to Common Stockholders, Basic	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic	14,000,000
Net Income (Loss) Available to Common Stockholders, Basic	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic	0
Interest and Debt Expense	us-gaap_InterestAndDebtExpense	2,000,000
Interest and Debt Expense	us-gaap_InterestAndDebtExpense	0
Interest and Debt Expense	us-gaap_InterestAndDebtExpense	4,000,000
Operating Segments [Member] | Southern Company Gas [Member] | Gas Pipeline Investments [Member]
Income Tax Expense (Benefit)	us-gaap_IncomeTaxExpenseBenefit	27,000,000
Income Tax Expense (Benefit)	us-gaap_IncomeTaxExpenseBenefit	35,000,000
Income Tax Expense (Benefit)	us-gaap_IncomeTaxExpenseBenefit	33,000,000
Operating Income (Loss)	us-gaap_OperatingIncomeLoss	20,000,000
Operating Income (Loss)	us-gaap_OperatingIncomeLoss	21,000,000
Operating Income (Loss)	us-gaap_OperatingIncomeLoss	21,000,000
Depreciation and Amortization Excluding Nuclear Fuel	so_DepreciationAndAmortizationExcludingNuclearFuel	5,000,000
Depreciation and Amortization Excluding Nuclear Fuel	so_DepreciationAndAmortizationExcludingNuclearFuel	5,000,000
Depreciation and Amortization Excluding Nuclear Fuel	so_DepreciationAndAmortizationExcludingNuclearFuel	5,000,000
Assets	us-gaap_Assets	1,577,000,000
Assets	us-gaap_Assets	1,467,000,000
Assets	us-gaap_Assets	1,597,000,000
Income (Loss) from Equity Method Investments	us-gaap_IncomeLossFromEquityMethodInvestments	148,000,000
Income (Loss) from Equity Method Investments	us-gaap_IncomeLossFromEquityMethodInvestments	141,000,000
Income (Loss) from Equity Method Investments	us-gaap_IncomeLossFromEquityMethodInvestments	50,000,000
Net Income (Loss) Available to Common Stockholders, Basic	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic	19,000,000
Net Income (Loss) Available to Common Stockholders, Basic	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic	99,000,000
Net Income (Loss) Available to Common Stockholders, Basic	us-gaap_NetIncomeLossAvailableToCommonStockholdersBasic	107,000,000
Revenues	us-gaap_Revenues	32,000,000
Revenues	us-gaap_Revenues	32,000,000
Revenues	us-gaap_Revenues	32,000,000
Interest and Debt Expense	us-gaap_InterestAndDebtExpense	25,000,000
Interest and Debt Expense	us-gaap_InterestAndDebtExpense	27,000,000
Interest and Debt Expense	us-gaap_InterestAndDebtExpense	$ 29,000,000