Alabama Power (ALP-PQ) 10-Q 27 Apr 22 2022 Q1 Quarterly report Financial data

Cover Page

Cover Page	3 Months Ended
	Mar. 31, 2022shares
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Mar. 31, 2022
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)	1,062,524,675
Entity Central Index Key	0000092122
Amendment Flag	false
Document Fiscal Year Focus	2022
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
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
2019 Series A Corporate Units
Document Information [Line Items]
Title of 12(b) Security	2019 Series A Corporate Units
Trading Symbol	SOLN
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 CO
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)	30,537,500
Entity Central Index Key	0000003153
ALABAMA POWER CO | 5.00% Series Class A Preferred Stock
Document Information [Line Items]
Title of 12(b) Security	5.00% Series Class A Preferred Stock
Trading Symbol	ALP PR Q
Security Exchange Name	NYSE
GEORGIA POWER CO
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)	9,261,500
Entity Central Index Key	0000041091
GEORGIA POWER CO | 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 CO
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)	1,121,000
Entity Central Index Key	0000066904
SOUTHERN POWER CO
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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)	1,000
Entity Central Index Key	0001160661
SOUTHERN POWER CO | Series 2016A 1.000% Senior Notes due 2022
Document Information [Line Items]
Title of 12(b) Security	Series 2016A 1.000% Senior Notes due 2022
Trading Symbol	SO/22B
Security Exchange Name	NYSE
SOUTHERN POWER CO | 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 Co 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 Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding (in shares)	100
Entity Central Index Key	0001004155

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income (Unaudited) - Southern - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Revenues:
Total operating revenues	$ 6,648	$ 5,910
Operating Expenses:
Other operations and maintenance	1,516	1,372
Depreciation and amortization	892	871
Taxes other than income taxes	372	345
Estimated loss on Plant Vogtle Units 3 and 4	0	48
Gain on dispositions, net	(23)	(44)
Total operating expenses	5,264	4,312
Operating Income	1,384	1,598
Other Income and (Expense):
Allowance for equity funds used during construction	51	46
Earnings from equity method investments	46	45
Interest expense, net of amounts capitalized	(462)	(450)
Other income (expense), net	145	58
Total other income and (expense)	(220)	(301)
Earnings Before Income Taxes	1,164	1,297
Income taxes (benefit)	173	190
Consolidated Net Income	991	1,107
Dividends on preferred stock of subsidiaries	4	4
Net loss attributable to noncontrolling interests	(45)	(32)
Net Income	$ 1,032	$ 1,135
Earnings per share -
Basic (in dollars per share)	$ 0.97	$ 1.07
Diluted (in dollars per share)	$ 0.97	$ 1.06
Average number of shares of common stock outstanding — (in millions)
Basic (in shares)	1,063	1,060
Diluted (in shares)	1,069	1,066
Retail electric revenues
Operating Revenues:
Total operating revenues	$ 3,613	$ 3,342
Wholesale Electric
Operating Revenues:
Total operating revenues	664	545
Other electric revenues
Operating Revenues:
Total operating revenues	177	170
Natural Gas
Operating Revenues:
Total operating revenues	2,058	1,694
Natural gas
Operating Expenses:
Less Gross Gas Costs	1,095	583
Alternative revenue programs
Operating Revenues:
Total operating revenues	0	2
Other revenues
Operating Revenues:
Total operating revenues	136	159
Operating Expenses:
Less Gross Gas Costs	69	82
Fuel
Operating Expenses:
Less Gross Gas Costs	1,111	848
Purchased power
Operating Expenses:
Less Gross Gas Costs	$ 232	$ 207

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Income (Unaudited) - Southern (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Total operating revenues	$ 6,648	$ 5,910
Natural Gas
Total operating revenues	2,058	1,694
Alternative revenue programs
Total operating revenues	$ 0	$ 2

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - Southern - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income	$ 991	$ 1,107
Qualifying hedges:
Changes in fair value, net of tax	19	(30)
Reclassification adjustment for amounts included in net income, net of tax	20	55
Pension and other postretirement benefit plans:
Reclassification adjustment for amounts included in net income, net of tax	3	3
Total other comprehensive income	42	28
Comprehensive Income	1,033	1,135
Dividends on preferred stock of subsidiaries	4	4
Comprehensive loss attributable to noncontrolling interests	(45)	(32)
Comprehensive Income	$ 1,074	$ 1,163

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - Southern (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Changes in fair value, tax	$ 8	$ (10)
Qualifying hedges, reclassification adjustment, tax	6	18
Reclassification adjustment for amounts included in net income, tax	$ 1	$ 1

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) - Southern - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Activities:
Net income (loss)	$ 991	$ 1,107
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	989	964
Deferred income taxes	40	140
Allowance for equity funds used during construction	(51)	(46)
Pension, postretirement, and other employee benefits	(123)	(78)
Settlement of asset retirement obligations	(87)	(109)
Stock based compensation expense	85	83
Estimated loss on Plant Vogtle Units 3 and 4	0	48
Storm damage accruals	52	54
Gain on dispositions, net	(20)	(41)
Natural gas cost under recovery – long-term	162	(185)
Retail fuel cost under recovery – long-term	(130)	0
Other, net	7	114
Changes in certain current assets and liabilities —
-Receivables	(217)	308
-Prepayments	(86)	(98)
-Materials and supplies	(28)	(27)
-Natural gas for sale, net of temporary LIFO liquidation	450	456
-Natural gas cost under recovery	(40)	(487)
-Other current assets	87	90
-Accounts payable	132	(216)
-Accrued taxes	(58)	(212)
-Accrued compensation	(470)	(417)
-Accrued interest	(128)	(90)
-Retail fuel cost over recovery	0	(53)
-Other current liabilities	35	(63)
Net cash provided from operating activities	1,592	1,242
Investing Activities:
Business acquisitions, net of cash acquired	0	(345)
Property additions	(1,419)	(1,678)
Nuclear decommissioning trust fund purchases	(294)	(550)
Nuclear decommissioning trust fund sales	289	546
Cost of removal, net of salvage	(227)	(85)
Change in construction payables, net	23	(116)
Payments pursuant to LTSAs	(37)	(60)
Other investing activities	110	45
Net cash used for investing activities	(1,555)	(2,243)
Financing Activities:
Increase in notes payable	137	182
Proceeds —
Long-term debt	700	2,150
Short-term borrowings	850	325
Common stock	38	14
Redemptions and repurchases —
Long-term debt	(977)	(384)
Short-term borrowings	(100)	(25)
Capital contributions from noncontrolling interests	73	313
Distributions to noncontrolling interests	(97)	(46)
Payment of common stock dividends	(702)	(678)
Other financing activities	(115)	(117)
Net cash provided from (used for) financing activities	(193)	1,734
Net Change in Cash, Cash Equivalents, and Restricted Cash	(156)	733
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	1,829	1,068
Cash, Cash Equivalents, and Restricted Cash at End of Period	1,673	1,801
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	515	519
Income taxes, net	(8)	(51)
Noncash transactions —
Accrued property additions at year-end	863	872
Contributions from noncontrolling interests	0	89
Contributions of wind turbine equipment	0	82
Right-of-use assets obtained under leases	3	76
Reassessment of right-of-use assets under operating leases	$ 40	$ 0

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Cash Flows (Unaudited) - Southern (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Cash Flows [Abstract]
Net cash paid for capitalized interest	$ 23	$ 21

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - Southern - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 1,662	$ 1,798
Receivables —
Customer accounts	2,006	1,806
Unbilled revenues	638	711
Other accounts and notes	509	523
Accumulated provision for uncollectible accounts	(89)	(78)
Materials and supplies	1,571	1,543
Fossil fuel for generation	411	450
Natural gas for sale	121	362
Prepaid expenses	739	330
Assets from risk management activities, net of collateral	405	151
Regulatory assets – asset retirement obligations	241	219
Natural gas cost under recovery	306	266
Other regulatory assets	576	653
Other current assets	201	231
Total current assets	9,297	8,965
Property, Plant, and Equipment:
In service	116,259	115,592
Less: Accumulated depreciation	34,645	34,079
Plant in service, net of depreciation	81,614	81,513
Nuclear fuel, at amortized cost	839	824
Construction work in progress	9,337	8,771
Total property, plant, and equipment	91,790	91,108
Other Property and Investments:
Goodwill	5,280	5,280
Nuclear decommissioning trusts, at fair value	2,403	2,542
Equity investments in unconsolidated subsidiaries	1,293	1,282
Other intangible assets, net of amortization	435	445
Miscellaneous property and investments	633	653
Total other property and investments	10,044	10,202
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,693	1,701
Deferred charges related to income taxes	833	824
Prepaid pension costs	1,772	1,657
Unamortized loss on reacquired debt	257	258
Regulatory assets – asset retirement obligations, deferred	5,683	5,466
Other regulatory assets, deferred	5,372	5,577
Other deferred charges and assets	1,898	1,776
Total deferred charges and other assets	17,508	17,259
Total Assets	128,639	127,534
Current Liabilities:
Securities due within one year	1,193	2,157
Notes payable	2,330	1,440
Accounts payable	2,251	2,169
Customer deposits	454	479
Accrued taxes —
Accrued income taxes	57	50
Other accrued taxes	415	641
Accrued interest	404	533
Accrued compensation	574	1,070
Asset retirement obligations	695	697
Operating lease obligations	245	250
Other regulatory liabilities	711	563
Other current liabilities	1,105	872
Total current liabilities	10,434	10,921
Long-term Debt	50,633	50,120
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	9,506	8,862
Deferred credits related to income taxes	5,365	5,401
Accumulated deferred ITCs	2,196	2,216
Employee benefit obligations	1,526	1,550
Operating lease obligations, deferred	1,521	1,503
Asset retirement obligations, deferred	11,016	10,990
Other cost of removal obligations	2,030	2,103
Other regulatory liabilities, deferred	526	485
Other deferred credits and liabilities	966	816
Total deferred credits and other liabilities	34,652	33,926
Total Liabilities	95,719	94,967
Redeemable preferred stock	291	291
Common Stockholder's Equity (See accompanying statements)	32,629	32,276
Total Liabilities and Stockholders' Equity	$ 128,639	$ 127,534

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) - Southern (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Statement of Financial Position [Abstract]
Other intangible assets, amortization	$ 317	$ 307

Condensed Consolidated Statem_7

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - Southern - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Treasury	Paid-In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Beginning balance (in shares) at Dec. 31, 2020		1,058	1
Beginning 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)	1,103				1,135		(32)
Other comprehensive income (loss)	28					28
Stock issued (in shares)		2
Stock issued	14	$ 5		9
Stock-based compensation	9			9
Cash dividends on common stock	(678)				(678)
Capital contributions from noncontrolling interests	403						403
Distributions to noncontrolling interests	(46)						(46)
Other	1			2			(1)
Ending balance (in shares) at Mar. 31, 2021		1,060	1
Ending balance at Mar. 31, 2021	33,068	$ 5,273	$ (46)	11,854	11,768	(367)	4,586
Beginning balance (in shares) at Dec. 31, 2021		1,061	1
Beginning 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)	987				1,032		(45)
Other comprehensive income (loss)	42					42
Stock issued (in shares)		3
Stock issued	38	$ 7		31
Stock-based compensation	6			6
Cash dividends on common stock	(702)				(702)
Capital contributions from noncontrolling interests	73						73
Distributions to noncontrolling interests	(98)						(98)
Other	7		$ (2)	7	2
Ending balance (in shares) at Mar. 31, 2022		1,064	1
Ending balance at Mar. 31, 2022	$ 32,629	$ 5,286	$ (49)	$ 11,994	$ 11,261	$ (195)	$ 4,332

Condensed Consolidated Statem_8

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - Southern (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Stockholders' Equity [Abstract]
Cash dividends (in dollars per share)	$ 0.66	$ 0.64

Condensed Statements of Income

Condensed Statements of Income (Unaudited) - APC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Revenues:
Total operating revenues	$ 6,648	$ 5,910
Operating Expenses:
Other operations and maintenance	1,516	1,372
Depreciation and amortization	892	871
Taxes other than income taxes	372	345
Total operating expenses	5,264	4,312
Operating Income	1,384	1,598
Other Income and (Expense):
Allowance for equity funds used during construction	51	46
Interest expense, net of amounts capitalized	(462)	(450)
Total other income (expense), net	145	58
Total other income and (expense)	(220)	(301)
Earnings Before Income Taxes	1,164	1,297
Income taxes (benefit)	173	190
Net income	991	1,107
Dividends on preferred stock of subsidiaries	4	4
Net Income	1,032	1,135
Retail electric revenues
Operating Revenues:
Total operating revenues	3,613	3,342
Wholesale Electric
Operating Revenues:
Total operating revenues	664	545
Other electric revenues
Operating Revenues:
Total operating revenues	177	170
Natural Gas
Operating Revenues:
Total operating revenues	2,058	1,694
Other revenues
Operating Revenues:
Total operating revenues	136	159
Operating Expenses:
Less Gross Gas Costs	69	82
Fuel
Operating Expenses:
Less Gross Gas Costs	1,111	848
Purchased power
Operating Expenses:
Less Gross Gas Costs	232	207
Alabama Power
Operating Revenues:
Total operating revenues	1,649	1,559
Operating Expenses:
Other operations and maintenance	409	361
Depreciation and amortization	215	211
Taxes other than income taxes	104	103
Total operating expenses	1,154	1,046
Operating Income	495	513
Other Income and (Expense):
Allowance for equity funds used during construction	16	12
Interest expense, net of amounts capitalized	(89)	(84)
Total other income (expense), net	36	32
Total other income and (expense)	(37)	(40)
Earnings Before Income Taxes	458	473
Income taxes (benefit)	107	110
Net income	351	363
Dividends on preferred stock of subsidiaries	4	4
Net Income	347	359
Alabama Power | Retail electric revenues
Operating Revenues:
Total operating revenues	1,379	1,352
Alabama Power | Wholesale revenues, non-affiliates
Operating Revenues:
Total operating revenues	114	92
Alabama Power | Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	65	32
Alabama Power | Other revenues
Operating Revenues:
Total operating revenues	91	83
Alabama Power | Fuel
Operating Expenses:
Less Gross Gas Costs	333	291
Alabama Power | Purchased power
Operating Expenses:
Less Gross Gas Costs	67	50
Alabama Power | Purchased power, affiliates
Operating Expenses:
Less Gross Gas Costs	$ 26	$ 30

Condensed Statements of Compreh

Condensed Statements of Comprehensive Income (Unaudited) - APC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net income	$ 991	$ 1,107
Qualifying hedges:
Changes in fair value, net of tax	19	(30)
Reclassification adjustment for amounts included in net income, net of tax	20	55
Total other comprehensive income	42	28
Comprehensive Income	1,033	1,135
Alabama Power
Net income	351	363
Qualifying hedges:
Changes in fair value, net of tax	(1)	0
Reclassification adjustment for amounts included in net income, net of tax	1	1
Total other comprehensive income	0	1
Comprehensive Income	$ 351	$ 364

Condensed Statements of Compr_2

Condensed Statements of Comprehensive Income (Unaudited) - APC (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Changes in fair value, tax	$ 8	$ (10)
Qualifying hedges, reclassification adjustment, tax	6	18
Alabama Power
Changes in fair value, tax	(1)	0
Qualifying hedges, reclassification adjustment, tax	$ 0	$ 0

Condensed Statements of Cash Fl

Condensed Statements of Cash Flows (Unaudited) - APC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Activities:
Net income (loss)	$ 991	$ 1,107
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	989	964
Deferred income taxes	40	140
Pension, postretirement, and other employee benefits	(123)	(78)
Settlement of asset retirement obligations	(87)	(109)
Other, net	7	114
Changes in certain current assets and liabilities —
-Receivables	(217)	308
-Prepayments	(86)	(98)
-Other current assets	87	90
-Accounts payable	132	(216)
-Accrued taxes	(58)	(212)
-Accrued compensation	(470)	(417)
-Retail fuel cost over recovery	0	(53)
-Other current liabilities	35	(63)
Net cash provided from operating activities	1,592	1,242
Investing Activities:
Property additions	(1,419)	(1,678)
Nuclear decommissioning trust fund purchases	(294)	(550)
Nuclear decommissioning trust fund sales	289	546
Cost of removal, net of salvage	(227)	(85)
Change in construction payables, net	23	(116)
Other investing activities	110	45
Net cash used for investing activities	(1,555)	(2,243)
Redemptions and repurchases —
Payment of common stock dividends	(702)	(678)
Other financing activities	(115)	(117)
Net cash provided from (used for) financing activities	(193)	1,734
Net Change in Cash, Cash Equivalents, and Restricted Cash	(156)	733
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	1,829	1,068
Cash, Cash Equivalents, and Restricted Cash at End of Period	1,673	1,801
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	515	519
Noncash transactions —
Accrued property additions at year-end	863	872
Right-of-use assets obtained under leases	3	76
Alabama Power
Operating Activities:
Net income (loss)	351	363
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	250	248
Deferred income taxes	35	33
Pension, postretirement, and other employee benefits	(48)	(29)
Settlement of asset retirement obligations	(38)	(49)
Retail fuel cost under recovery – long-term	(46)	0
Other, net	(27)	(14)
Changes in certain current assets and liabilities —
-Receivables	(4)	40
-Fossil fuel stock	23	38
-Prepayments	(85)	(73)
-Other current assets	(10)	(16)
-Accounts payable	(237)	(299)
-Accrued taxes	102	104
-Accrued compensation	(99)	(105)
-Retail fuel cost over recovery	0	(18)
-Other current liabilities	(13)	(9)
Net cash provided from operating activities	154	214
Investing Activities:
Property additions	(343)	(466)
Nuclear decommissioning trust fund purchases	(72)	(310)
Nuclear decommissioning trust fund sales	72	310
Cost of removal, net of salvage	(60)	(23)
Change in construction payables, net	39	32
Other investing activities	(1)	(9)
Net cash used for investing activities	(365)	(466)
Proceeds —
Senior notes	700	0
Redemptions and repurchases —
Senior notes	(550)	0
Capital contributions from parent company	625	600
Payment of common stock dividends	(254)	(246)
Other financing activities	(17)	(13)
Net cash provided from (used for) financing activities	504	341
Net Change in Cash, Cash Equivalents, and Restricted Cash	293	89
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	1,060	530
Cash, Cash Equivalents, and Restricted Cash at End of Period	1,353	619
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	110	93
Noncash transactions —
Accrued property additions at year-end	188	198
Right-of-use assets obtained under leases	$ 1	$ 1

Condensed Statements of Cash _2

Condensed Statements of Cash Flows (Unaudited) - APC (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net cash paid for capitalized interest	$ 23	$ 21
Alabama Power
Net cash paid for capitalized interest	$ 4	$ 3

Condensed Balance Sheets (Unaud

Condensed Balance Sheets (Unaudited) - APC - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 1,662	$ 1,798
Receivables —
Customer accounts	2,006	1,806
Unbilled revenues	638	711
Other accounts and notes	509	523
Accumulated provision for uncollectible accounts	(89)	(78)
Fossil fuel for generation	411	450
Materials and supplies	1,571	1,543
Prepaid expenses	739	330
Other regulatory assets	576	653
Other current assets	201	231
Total current assets	9,297	8,965
Property, Plant, and Equipment:
In service	116,259	115,592
Less: Accumulated depreciation	34,645	34,079
Plant in service, net of depreciation	81,614	81,513
Nuclear fuel, at amortized cost	839	824
Construction work in progress	9,337	8,771
Total property, plant, and equipment	91,790	91,108
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	2,403	2,542
Equity investments in unconsolidated subsidiaries	1,293	1,282
Miscellaneous property and investments	633	653
Total other property and investments	10,044	10,202
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,693	1,701
Deferred charges related to income taxes	833	824
Regulatory assets – asset retirement obligations, deferred	5,683	5,466
Other regulatory assets, deferred	5,372	5,577
Other deferred charges and assets	1,898	1,776
Total deferred charges and other assets	17,508	17,259
Total Assets	128,639	127,534
Current Liabilities:
Securities due within one year	1,193	2,157
Accounts payable —
Customer deposits	454	479
Accrued interest	404	533
Accrued compensation	574	1,070
Asset retirement obligations	695	697
Other regulatory liabilities	711	563
Other current liabilities	1,105	872
Total current liabilities	10,434	10,921
Long-term Debt	50,633	50,120
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	9,506	8,862
Deferred credits related to income taxes	5,365	5,401
Accumulated deferred ITCs	2,196	2,216
Employee benefit obligations	1,526	1,550
Operating lease obligations, deferred	1,521	1,503
Asset retirement obligations, deferred	11,016	10,990
Other cost of removal obligations	2,030	2,103
Other regulatory liabilities, deferred	526	485
Other deferred credits and liabilities	966	816
Total deferred credits and other liabilities	34,652	33,926
Total Liabilities	95,719	94,967
Redeemable preferred stock	291	291
Common Stockholder's Equity (See accompanying statements)	32,629	32,276
Total Liabilities and Stockholders' Equity	128,639	127,534
Alabama Power
Current Assets:
Cash and cash equivalents	1,353	1,060
Receivables —
Customer accounts	417	410
Unbilled revenues	127	138
Affiliated	36	37
Other accounts and notes	64	55
Accumulated provision for uncollectible accounts	(15)	(14)
Fossil fuel for generation	136	159
Materials and supplies	550	548
Prepaid expenses	126	41
Other regulatory assets	191	208
Other current assets	131	67
Total current assets	3,116	2,709
Property, Plant, and Equipment:
In service	33,333	33,135
Less: Accumulated depreciation	10,451	10,313
Plant in service, net of depreciation	22,882	22,822
Nuclear fuel, at amortized cost	246	247
Construction work in progress	1,249	1,147
Total property, plant, and equipment	24,377	24,216
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	1,257	1,325
Equity investments in unconsolidated subsidiaries	57	57
Miscellaneous property and investments	126	126
Total other property and investments	1,440	1,508
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	97	108
Deferred charges related to income taxes	243	240
Prepaid pension and other postretirement benefit costs	546	513
Regulatory assets – asset retirement obligations, deferred	1,663	1,547
Other regulatory assets, deferred	1,717	1,807
Other deferred charges and assets	371	334
Total deferred charges and other assets	4,637	4,549
Total Assets	33,570	32,982
Current Liabilities:
Securities due within one year	201	751
Accounts payable —
Affiliated	194	309
Other	372	459
Customer deposits	106	106
Accrued taxes	200	98
Accrued interest	77	100
Accrued compensation	124	219
Asset retirement obligations	322	320
Other regulatory liabilities	148	215
Other current liabilities	128	125
Total current liabilities	1,872	2,702
Long-term Debt	9,631	8,936
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	3,619	3,573
Deferred credits related to income taxes	1,959	1,968
Accumulated deferred ITCs	86	88
Employee benefit obligations	179	171
Operating lease obligations, deferred	64	66
Asset retirement obligations, deferred	4,013	4,014
Other cost of removal obligations	144	192
Other regulatory liabilities, deferred	224	210
Other deferred credits and liabilities	56	58
Total deferred credits and other liabilities	10,344	10,340
Total Liabilities	21,847	21,978
Redeemable preferred stock	291	291
Common Stockholder's Equity (See accompanying statements)	11,432	10,713
Total Liabilities and Stockholders' Equity	$ 33,570	$ 32,982

Condensed Statements of Common

Condensed Statements of Common Stockholders' Equity (Unaudited) - APC - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Alabama Power	Alabama PowerCommon Stock	Alabama PowerPaid-In Capital	Alabama PowerRetained Earnings (Accumulated Deficit)	Alabama PowerAccumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2020		1,058					31
Beginning 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]
Net income after dividends on preferred stock	1,135					359			359
Capital contributions from parent company						602		602
Other comprehensive income (loss)	28				28	1				1
Cash dividends on common stock	(678)			(678)		(246)			(246)
Ending balance (in shares) at Mar. 31, 2021		1,060					31
Ending balance at Mar. 31, 2021	33,068	$ 5,273	11,854	11,768	(367)	10,526	$ 1,222	6,015	3,307	(18)
Beginning balance (in shares) at Dec. 31, 2021		1,061					31
Beginning 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]
Net income after dividends on preferred stock	1,032					347			347
Capital contributions from parent company						626		626
Other comprehensive income (loss)	42				42
Cash dividends on common stock	(702)			(702)		(254)			(254)
Ending balance (in shares) at Mar. 31, 2022		1,064					31
Ending balance at Mar. 31, 2022	$ 32,629	$ 5,286	$ 11,994	$ 11,261	$ (195)	$ 11,432	$ 1,222	$ 6,682	$ 3,541	$ (13)

Condensed Statements of Incom_2

Condensed Statements of Income (Unaudited) - GPC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Revenues:
Total operating revenues	$ 6,648	$ 5,910
Operating Expenses:
Other operations and maintenance	1,516	1,372
Depreciation and amortization	892	871
Taxes other than income taxes	372	345
Estimated loss on Plant Vogtle Units 3 and 4	0	48
Total operating expenses	5,264	4,312
Operating Income	1,384	1,598
Other Income and (Expense):
Allowance for equity funds used during construction	51	46
Interest expense, net of amounts capitalized	(462)	(450)
Other income (expense), net	145	58
Total other income and (expense)	(220)	(301)
Earnings Before Income Taxes	1,164	1,297
Income taxes (benefit)	173	190
Consolidated Net Income	991	1,107
Retail electric revenues
Operating Revenues:
Total operating revenues	3,613	3,342
Wholesale Electric
Operating Revenues:
Total operating revenues	664	545
Other electric revenues
Operating Revenues:
Total operating revenues	177	170
Natural Gas
Operating Revenues:
Total operating revenues	2,058	1,694
Other revenues
Operating Revenues:
Total operating revenues	136	159
Operating Expenses:
Less Gross Gas Costs	69	82
Fuel
Operating Expenses:
Less Gross Gas Costs	1,111	848
Purchased power
Operating Expenses:
Less Gross Gas Costs	232	207
Georgia Power
Operating Revenues:
Total operating revenues	2,208	1,970
Operating Expenses:
Other operations and maintenance	517	474
Depreciation and amortization	351	338
Taxes other than income taxes	125	116
Estimated loss on Plant Vogtle Units 3 and 4	0	48
Total operating expenses	1,768	1,569
Operating Income	440	401
Other Income and (Expense):
Allowance for equity funds used during construction	32	31
Interest expense, net of amounts capitalized	(107)	(104)
Other income (expense), net	50	41
Total other income and (expense)	(25)	(32)
Earnings Before Income Taxes	415	369
Income taxes (benefit)	30	18
Consolidated Net Income	385	351
Georgia Power | Retail electric revenues
Operating Revenues:
Total operating revenues	2,017	1,787
Georgia Power | Wholesale Electric
Operating Revenues:
Total operating revenues	66	43
Georgia Power | Other revenues
Operating Revenues:
Total operating revenues	125	140
Georgia Power | Fuel
Operating Expenses:
Less Gross Gas Costs	419	313
Georgia Power | Purchased power
Operating Expenses:
Less Gross Gas Costs	150	144
Georgia Power | Purchased power, affiliates
Operating Expenses:
Less Gross Gas Costs	$ 206	$ 136

Condensed Statements of Compr_3

Condensed Statements of Comprehensive Income (Unaudited) - GPC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net income	$ 991	$ 1,107
Qualifying hedges:
Changes in fair value, net of tax	19	(30)
Reclassification adjustment for amounts included in net income, net of tax	20	55
Total other comprehensive income	42	28
Comprehensive Income	1,033	1,135
Georgia Power
Net income	385	351
Qualifying hedges:
Changes in fair value, net of tax	9	0
Reclassification adjustment for amounts included in net income, net of tax	1	2
Total other comprehensive income	10	2
Comprehensive Income	$ 395	$ 353

Condensed Statements of Compr_4

Condensed Statements of Comprehensive Income (Unaudited) - GPC (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Changes in fair value, tax	$ 8	$ (10)
Qualifying hedges, reclassification adjustment, tax	6	18
Georgia Power
Changes in fair value, tax	3	0
Qualifying hedges, reclassification adjustment, tax	$ 1	$ 0

Condensed Statements of Cash _3

Condensed Statements of Cash Flows (Unaudited) - GPC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Activities:
Net income (loss)	$ 991	$ 1,107
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	989	964
Deferred income taxes	40	140
Pension, postretirement, and other employee benefits	(123)	(78)
Settlement of asset retirement obligations	(87)	(109)
Storm damage accruals	52	54
Retail fuel cost under recovery – long-term	(130)	0
Estimated loss on Plant Vogtle Units 3 and 4	0	48
Other, net	7	114
Changes in certain current assets and liabilities —
-Receivables	(217)	308
-Other current assets	87	90
-Accounts payable	132	(216)
-Accrued taxes	(58)	(212)
-Accrued compensation	(470)	(417)
-Accrued interest	(128)	(90)
-Other current liabilities	35	(63)
Net cash provided from operating activities	1,592	1,242
Investing Activities:
Property additions	(1,419)	(1,678)
Nuclear decommissioning trust fund purchases	(294)	(550)
Nuclear decommissioning trust fund sales	289	546
Cost of removal, net of salvage	(227)	(85)
Other investing activities	110	45
Net cash used for investing activities	(1,555)	(2,243)
Financing Activities:
Increase in notes payable	137	182
Proceeds —
Short-term borrowings	850	325
Redemptions and repurchases —
Payment of common stock dividends	(702)	(678)
Other financing activities	(115)	(117)
Net cash provided from (used for) financing activities	(193)	1,734
Net Change in Cash, Cash Equivalents, and Restricted Cash	(156)	733
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	1,829	1,068
Cash, Cash Equivalents, and Restricted Cash at End of Period	1,673	1,801
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	515	519
Noncash transactions —
Accrued property additions at year-end	863	872
Georgia Power
Operating Activities:
Net income (loss)	385	351
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	397	384
Deferred income taxes	(6)	(86)
Pension, postretirement, and other employee benefits	(63)	(43)
Settlement of asset retirement obligations	(41)	(49)
Storm damage accruals	53	53
Retail fuel cost under recovery – long-term	(84)	0
Estimated loss on Plant Vogtle Units 3 and 4	0	48
Other, net	(85)	(19)
Changes in certain current assets and liabilities —
-Receivables	0	176
-Prepaid income taxes	(36)	0
-Other current assets	22	4
-Accounts payable	39	(74)
-Accrued taxes	(78)	(110)
-Accrued compensation	(79)	(68)
-Accrued interest	(43)	(34)
-Other current liabilities	(20)	(44)
Net cash provided from operating activities	361	489
Investing Activities:
Property additions	(749)	(775)
Nuclear decommissioning trust fund purchases	(221)	(241)
Nuclear decommissioning trust fund sales	217	236
Cost of removal, net of salvage	(140)	(40)
Change in construction payables	14	(103)
Proceeds from dispositions	56	1
Other investing activities	14	9
Net cash used for investing activities	(809)	(913)
Financing Activities:
Increase in notes payable	410	145
Proceeds —
Senior notes	0	750
Short-term borrowings	450	0
Redemptions and repurchases —
Senior notes	(400)	(325)
FFB loan	(24)	(25)
Capital contributions from parent company	445	330
Payment of common stock dividends	(423)	(412)
Other financing activities	(17)	(19)
Net cash provided from (used for) financing activities	441	444
Net Change in Cash, Cash Equivalents, and Restricted Cash	(7)	20
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	33	9
Cash, Cash Equivalents, and Restricted Cash at End of Period	26	29
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	139	128
Noncash transactions —
Accrued property additions at year-end	459	445
Right-of-use assets obtained under operating leases	$ 1	$ 3

Condensed Statements of Cash _4

Condensed Statements of Cash Flows (Unaudited) - GPC (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net cash paid for capitalized interest	$ 23	$ 21
Georgia Power
Net cash paid for capitalized interest	$ 16	$ 15

Condensed Balance Sheets (Una_2

Condensed Balance Sheets (Unaudited) - GPC - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 1,662	$ 1,798
Receivables —
Customer accounts	2,006	1,806
Unbilled revenues	638	711
Other accounts and notes	509	523
Fossil fuel for generation	411	450
Materials and supplies	1,571	1,543
Regulatory assets – asset retirement obligations	241	219
Assets from risk management activities	405	151
Other regulatory assets	576	653
Other current assets	201	231
Total current assets	9,297	8,965
Property, Plant, and Equipment:
In service	116,259	115,592
Less: Accumulated depreciation	34,645	34,079
Plant in service, net of depreciation	81,614	81,513
Nuclear fuel, at amortized cost	839	824
Construction work in progress	9,337	8,771
Total property, plant, and equipment	91,790	91,108
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	2,403	2,542
Equity investments in unconsolidated subsidiaries	1,293	1,282
Miscellaneous property and investments	633	653
Total other property and investments	10,044	10,202
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,693	1,701
Deferred charges related to income taxes	833	824
Prepaid pension costs	1,772	1,657
Regulatory assets – asset retirement obligations, deferred	5,683	5,466
Other regulatory assets, deferred	5,372	5,577
Other deferred charges and assets	1,898	1,776
Total deferred charges and other assets	17,508	17,259
Total Assets	128,639	127,534
Current Liabilities:
Securities due within one year	1,193	2,157
Notes payable	2,330	1,440
Accounts payable —
Customer deposits	454	479
Accrued interest	404	533
Accrued compensation	574	1,070
Operating lease obligations	245	250
Asset retirement obligations	695	697
Other regulatory liabilities	711	563
Other current liabilities	1,105	872
Total current liabilities	10,434	10,921
Long-term Debt	50,633	50,120
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	9,506	8,862
Deferred credits related to income taxes	5,365	5,401
Accumulated deferred ITCs	2,196	2,216
Employee benefit obligations	1,526	1,550
Operating lease obligations, deferred	1,521	1,503
Asset retirement obligations, deferred	11,016	10,990
Other deferred credits and liabilities	966	816
Total deferred credits and other liabilities	34,652	33,926
Total Liabilities	95,719	94,967
Common Stockholder's Equity (See accompanying statements)	32,629	32,276
Total Liabilities and Stockholders' Equity	128,639	127,534
Georgia Power
Current Assets:
Cash and cash equivalents	26	33
Receivables —
Customer accounts	561	547
Unbilled revenues	216	231
Joint owner accounts	60	116
Affiliated	12	25
Other accounts and notes	35	44
Fossil fuel for generation	231	248
Materials and supplies	681	670
Regulatory assets – storm damage	4	48
Regulatory assets – asset retirement obligations	200	178
Assets from risk management activities	162	48
Other regulatory assets	248	241
Other current assets	124	130
Total current assets	2,560	2,559
Property, Plant, and Equipment:
In service	41,592	41,332
Less: Accumulated depreciation	13,029	12,854
Plant in service, net of depreciation	28,563	28,478
Nuclear fuel, at amortized cost	593	577
Construction work in progress	7,086	6,688
Total property, plant, and equipment	36,242	35,743
Other Property and Investments:
Nuclear decommissioning trusts, at fair value	1,146	1,217
Equity investments in unconsolidated subsidiaries	51	50
Miscellaneous property and investments	74	69
Total other property and investments	1,271	1,336
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,120	1,157
Deferred charges related to income taxes	557	550
Prepaid pension costs	608	563
Deferred under recovered fuel clause revenues	494	410
Regulatory assets – asset retirement obligations, deferred	3,781	3,688
Other regulatory assets, deferred	2,067	1,964
Other deferred charges and assets	506	491
Total deferred charges and other assets	9,133	8,823
Total Assets	49,206	48,461
Current Liabilities:
Securities due within one year	275	675
Notes payable	860	0
Accounts payable —
Affiliated	548	757
Other	873	702
Customer deposits	257	259
Accrued taxes	196	335
Accrued interest	93	136
Accrued compensation	124	232
Operating lease obligations	156	156
Asset retirement obligations	314	317
Other regulatory liabilities	336	280
Other current liabilities	292	254
Total current liabilities	4,324	4,103
Long-term Debt	13,088	13,109
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	3,155	3,019
Deferred credits related to income taxes	2,303	2,321
Accumulated deferred ITCs	326	328
Employee benefit obligations	390	402
Operating lease obligations, deferred	989	999
Asset retirement obligations, deferred	6,526	6,507
Other deferred credits and liabilities	456	439
Total deferred credits and other liabilities	14,145	14,015
Total Liabilities	31,557	31,227
Common Stockholder's Equity (See accompanying statements)	17,649	17,234
Total Liabilities and Stockholders' Equity	$ 49,206	$ 48,461

Condensed Statements of Commo_2

Condensed Statements of Common Stockholders' Equity (Unaudited) - GPC - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Georgia Power	Georgia PowerCommon Stock	Georgia PowerPaid-In Capital	Georgia PowerRetained Earnings (Accumulated Deficit)	Georgia PowerAccumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2020		1,058					9
Beginning 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	1,107					351			351
Capital contributions from parent company						332		332
Other comprehensive income (loss)	28				28	2				2
Cash dividends on common stock	(678)			(678)		(412)			(412)
Ending balance (in shares) at Mar. 31, 2021		1,060					9
Ending balance at Mar. 31, 2021	33,068	$ 5,273	11,854	11,768	(367)	16,774	$ 398	12,693	3,728	(45)
Beginning balance (in shares) at Dec. 31, 2021		1,061					9
Beginning 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	991					385			385
Capital contributions from parent company						443		443
Other comprehensive income (loss)	42				42	10				10
Cash dividends on common stock	(702)			(702)		(423)			(423)
Ending balance (in shares) at Mar. 31, 2022		1,064					9
Ending balance at Mar. 31, 2022	$ 32,629	$ 5,286	$ 11,994	$ 11,261	$ (195)	$ 17,649	$ 398	$ 14,596	$ 2,686	$ (31)

Condensed Statements of Commo_3

Condensed Statements of Common Stockholders' Equity (Unaudited) - GPC (Parenthetical) - $ / shares	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Stockholders' Equity [Abstract]
Cash dividends (in dollars per share)	$ 0.66	$ 0.64

Condensed Statements of Incom_3

Condensed Statements of Income and Comprehensive Income (Unaudited) - MPC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Revenues:
Total operating revenues	$ 6,648	$ 5,910
Operating Expenses:
Other operations and maintenance	1,516	1,372
Depreciation and amortization	892	871
Taxes other than income taxes	372	345
Total operating expenses	5,264	4,312
Operating Income	1,384	1,598
Other Income and (Expense):
Interest expense, net of amounts capitalized	(462)	(450)
Other income (expense), net	145	58
Total other income and (expense)	(220)	(301)
Earnings Before Income Taxes	1,164	1,297
Income taxes (benefit)	173	190
Consolidated Net Income	991	1,107
Retail electric revenues
Operating Revenues:
Total operating revenues	3,613	3,342
Wholesale Electric
Operating Revenues:
Total operating revenues	664	545
Other electric revenues
Operating Revenues:
Total operating revenues	177	170
Natural Gas
Operating Revenues:
Total operating revenues	2,058	1,694
Other revenues
Operating Revenues:
Total operating revenues	136	159
Operating Expenses:
Less Gross Gas Costs	69	82
Mississippi Power
Operating Revenues:
Total operating revenues	335	307
Operating Expenses:
Other operations and maintenance	76	68
Depreciation and amortization	45	47
Taxes other than income taxes	29	31
Total operating expenses	282	252
Operating Income	53	55
Other Income and (Expense):
Interest expense, net of amounts capitalized	(13)	(14)
Other income (expense), net	10	8
Total other income and (expense)	(3)	(6)
Earnings Before Income Taxes	50	49
Income taxes (benefit)	8	4
Consolidated Net Income	42	45
Mississippi Power | Retail electric revenues
Operating Revenues:
Total operating revenues	217	204
Mississippi Power | Wholesale revenues, non-affiliates
Operating Revenues:
Total operating revenues	68	63
Mississippi Power | Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	42	33
Mississippi Power | Other revenues
Operating Revenues:
Total operating revenues	8	7
Mississippi Power | Fuel and purchased power
Operating Expenses:
Less Gross Gas Costs	$ 132	$ 106

Condensed Statements of Cash _5

Condensed Statements of Cash Flows (Unaudited) - MPC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Activities:
Net income (loss)	$ 991	$ 1,107
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	989	964
Deferred income taxes	40	140
Other, net	7	114
Changes in certain current assets and liabilities —
-Receivables	(217)	308
-Retail fuel cost over recovery	0	(53)
-Other current assets	87	90
-Accounts payable	132	(216)
-Accrued taxes	(58)	(212)
-Accrued compensation	(470)	(417)
-Other current liabilities	35	(63)
Net cash provided from operating activities	1,592	1,242
Investing Activities:
Property additions	(1,419)	(1,678)
Construction payables	23	(116)
Payments pursuant to LTSAs	(37)	(60)
Other investing activities	110	45
Net cash used for investing activities	(1,555)	(2,243)
Financing Activities:
Increase in notes payable	137	182
Payment of common stock dividends	(702)	(678)
Net cash provided from (used for) financing activities	(193)	1,734
Net Change in Cash, Cash Equivalents, and Restricted Cash	(156)	733
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	1,829	1,068
Cash, Cash Equivalents, and Restricted Cash at End of Period	1,673	1,801
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	515	519
Noncash transactions —
Accrued property additions at year-end	863	872
Mississippi Power
Operating Activities:
Net income (loss)	42	45
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	55	53
Deferred income taxes	(5)	4
Other, net	17	(14)
Changes in certain current assets and liabilities —
-Receivables	(7)	7
-Retail fuel cost over recovery	(11)	0
-Other current assets	(11)	1
-Accounts payable	(9)	(30)
-Accrued taxes	(63)	(75)
-Accrued compensation	(18)	(16)
-Other current liabilities	(6)	(13)
Net cash provided from operating activities	(16)	(38)
Investing Activities:
Property additions	(45)	(45)
Construction payables	(8)	(8)
Payments pursuant to LTSAs	(8)	(7)
Other investing activities	(7)	(7)
Net cash used for investing activities	(68)	(67)
Financing Activities:
Increase in notes payable	25	29
Capital contributions from parent company	50	100
Payment of common stock dividends	(43)	(39)
Net cash provided from (used for) financing activities	32	90
Net Change in Cash, Cash Equivalents, and Restricted Cash	(52)	(15)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	61	39
Cash, Cash Equivalents, and Restricted Cash at End of Period	9	24
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	22	16
Noncash transactions —
Accrued property additions at year-end	$ 17	$ 26

Condensed Statements of Cash _6

Condensed Statements of Cash Flows (Unaudited) - MPC (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net cash paid for capitalized interest	$ 23	$ 21

Condensed Balance Sheets (Una_3

Condensed Balance Sheets (Unaudited) - MPC - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 1,662	$ 1,798
Receivables —
Customer accounts	2,006	1,806
Unbilled revenues	638	711
Other accounts and notes	509	523
Fossil fuel for generation	411	450
Materials and supplies	1,571	1,543
Assets from risk management activities	405	151
Other regulatory assets	576	653
Other current assets	201	231
Total current assets	9,297	8,965
Property, Plant, and Equipment:
In service	116,259	115,592
Less: Accumulated depreciation	34,645	34,079
Plant in service, net of depreciation	81,614	81,513
Construction work in progress	9,337	8,771
Total property, plant, and equipment	91,790	91,108
Other Property and Investments:
Total other property and investments	10,044	10,202
Deferred Charges and Other Assets:
Deferred charges related to income taxes	833	824
Regulatory assets – asset retirement obligations, deferred	5,683	5,466
Other regulatory assets, deferred	5,372	5,577
Other deferred charges and assets	1,898	1,776
Total deferred charges and other assets	17,508	17,259
Total Assets	128,639	127,534
Current Liabilities:
Securities due within one year	1,193	2,157
Notes payable	2,330	1,440
Accounts payable —
Accrued compensation	574	1,070
Asset retirement obligations	695	697
Other regulatory liabilities	711	563
Other current liabilities	1,105	872
Total current liabilities	10,434	10,921
Long-term Debt	50,633	50,120
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	9,506	8,862
Deferred credits related to income taxes	5,365	5,401
Employee benefit obligations	1,526	1,550
Asset retirement obligations, deferred	11,016	10,990
Other cost of removal obligations	2,030	2,103
Other regulatory liabilities, deferred	526	485
Other deferred credits and liabilities	966	816
Total deferred credits and other liabilities	34,652	33,926
Total Liabilities	95,719	94,967
Total Liabilities and Stockholders' Equity	128,639	127,534
Mississippi Power
Current Assets:
Cash and cash equivalents	9	61
Receivables —
Customer accounts	65	37
Unbilled revenues	36	34
Affiliated	17	29
Other accounts and notes	30	28
Fossil fuel for generation	30	28
Materials and supplies	72	70
Assets from risk management activities	94	28
Other regulatory assets	61	54
Other current assets	10	13
Total current assets	424	382
Property, Plant, and Equipment:
In service	5,149	5,106
Less: Accumulated depreciation	1,626	1,591
Plant in service, net of depreciation	3,523	3,515
Construction work in progress	111	127
Total property, plant, and equipment	3,634	3,642
Other Property and Investments:
Total other property and investments	177	179
Deferred Charges and Other Assets:
Deferred charges related to income taxes	30	31
Prepaid pension costs	85	79
Regulatory assets – asset retirement obligations, deferred	235	232
Other regulatory assets, deferred	298	317
Accumulated deferred income taxes	115	118
Other deferred charges and assets	127	100
Total deferred charges and other assets	890	877
Total Assets	5,125	5,080
Current Liabilities:
Securities due within one year	1	1
Notes payable	25	0
Accounts payable —
Affiliated	58	81
Other	53	47
Accrued taxes	56	120
Accrued compensation	20	36
Asset retirement obligations	28	30
Other regulatory liabilities	120	59
Other current liabilities	55	65
Total current liabilities	416	439
Long-term Debt	1,510	1,510
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	462	464
Deferred credits related to income taxes	269	269
Employee benefit obligations	88	88
Asset retirement obligations, deferred	161	160
Other cost of removal obligations	194	195
Other regulatory liabilities, deferred	84	64
Other deferred credits and liabilities	24	24
Total deferred credits and other liabilities	1,282	1,264
Total Liabilities	3,208	3,213
Total common stockholders' equity	1,917	1,867
Total Liabilities and Stockholders' Equity	$ 5,125	$ 5,080

Condensed Statements of Commo_4

Condensed Statements of Common Stockholders' Equity (Unaudited) - MPC - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Paid-In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Mississippi Power	Mississippi PowerCommon Stock	Mississippi PowerPaid-In Capital	Mississippi PowerRetained Earnings (Accumulated Deficit)	Mississippi PowerAccumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2020		1,058					1
Beginning 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]
Net income	1,135					45			45
Capital contributions from parent company						100		100
Cash dividends on common stock	(678)			(678)		(39)			(39)
Ending balance (in shares) at Mar. 31, 2021		1,060					1
Ending balance at Mar. 31, 2021	33,068	$ 5,273	11,854	11,768	(367)	1,848	$ 38	4,560	(2,748)	(2)
Beginning balance (in shares) at Dec. 31, 2021		1,061					1
Beginning 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]
Net income	1,032					42			42
Capital contributions from parent company						51		51
Cash dividends on common stock	(702)			(702)		(43)			(43)
Ending balance (in shares) at Mar. 31, 2022		1,064					1
Ending balance at Mar. 31, 2022	$ 32,629	$ 5,286	$ 11,994	$ 11,261	$ (195)	$ 1,917	$ 38	$ 4,633	$ (2,754)	$ 0

Condensed Consolidated Statem_9

Condensed Consolidated Statements of Income (Unaudited) - SPC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Revenues:
Total operating revenues	$ 6,648	$ 5,910
Operating Expenses:
Other operations and maintenance	1,516	1,372
Depreciation and amortization	892	871
Taxes other than income taxes	372	345
Gain on dispositions, net	(23)	(44)
Total operating expenses	5,264	4,312
Operating Income	1,384	1,598
Other Income and (Expense):
Interest expense, net of amounts capitalized	(462)	(450)
Other income (expense), net	145	58
Total other income and (expense)	(220)	(301)
Earnings Before Income Taxes	1,164	1,297
Income taxes (benefit)	173	190
Consolidated Net Income	991	1,107
Net loss attributable to noncontrolling interests	(45)	(32)
Retail electric revenues
Operating Revenues:
Total operating revenues	3,613	3,342
Wholesale Electric
Operating Revenues:
Total operating revenues	664	545
Other electric revenues
Operating Revenues:
Total operating revenues	177	170
Natural Gas
Operating Revenues:
Total operating revenues	2,058	1,694
Other revenues
Operating Revenues:
Total operating revenues	136	159
Operating Expenses:
Less Gross Gas Costs	69	82
Fuel
Operating Expenses:
Less Gross Gas Costs	1,111	848
Purchased power
Operating Expenses:
Less Gross Gas Costs	232	207
Southern Power
Operating Revenues:
Total operating revenues	539	440
Operating Expenses:
Other operations and maintenance	105	101
Depreciation and amortization	120	119
Taxes other than income taxes	13	12
Gain on dispositions, net	(2)	(39)
Total operating expenses	489	354
Operating Income	50	86
Other Income and (Expense):
Interest expense, net of amounts capitalized	(37)	(38)
Other income (expense), net	2	7
Total other income and (expense)	(35)	(31)
Earnings Before Income Taxes	15	55
Income taxes (benefit)	(12)	(10)
Consolidated Net Income	27	65
Net loss attributable to noncontrolling interests	(45)	(32)
Net Income	72	97
Southern Power | Wholesale revenues, non-affiliates
Operating Revenues:
Total operating revenues	426	355
Southern Power | Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	105	81
Southern Power | Other revenues
Operating Revenues:
Total operating revenues	8	4
Southern Power | Fuel
Operating Expenses:
Less Gross Gas Costs	232	141
Southern Power | Purchased power
Operating Expenses:
Less Gross Gas Costs	$ 21	$ 20

Condensed Consolidated State_10

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - SPC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net income	$ 991	$ 1,107
Qualifying hedges:
Changes in fair value, net of tax	19	(30)
Reclassification adjustment for amounts included in net income, net of tax	20	55
Pension and other postretirement benefit plans:
Reclassification adjustment for amounts included in net income, net of tax	3	3
Total other comprehensive income	42	28
Comprehensive Income	1,033	1,135
Comprehensive loss attributable to noncontrolling interests	(45)	(32)
Comprehensive Income	1,074	1,163
Southern Power
Net income	27	65
Qualifying hedges:
Changes in fair value, net of tax	(17)	(33)
Reclassification adjustment for amounts included in net income, net of tax	22	48
Pension and other postretirement benefit plans:
Reclassification adjustment for amounts included in net income, net of tax	0	1
Total other comprehensive income	5	16
Comprehensive Income	32	81
Comprehensive loss attributable to noncontrolling interests	(45)	(32)
Comprehensive Income	$ 77	$ 113

Condensed Consolidated State_11

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - SPC (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Changes in fair value, tax	$ 8	$ (10)
Qualifying hedges, reclassification adjustment, tax	6	18
Reclassification adjustment for amounts included in net income, tax	1	1
Southern Power
Changes in fair value, tax	(6)	(11)
Qualifying hedges, reclassification adjustment, tax	7	15
Reclassification adjustment for amounts included in net income, tax	$ 0	$ 0

Condensed Consolidated State_12

Condensed Consolidated Statements of Cash Flows (Unaudited) - SPC - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Activities:
Net income (loss)	$ 991	$ 1,107
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	989	964
Deferred income taxes	40	140
Gain on dispositions, net	(20)	(41)
Other, net	7	114
Changes in certain current assets and liabilities —
-Receivables	(217)	308
-Other current assets	87	90
-Accounts payable	132	(216)
-Accrued taxes	(58)	(212)
-Other current liabilities	35	(63)
Net cash provided from operating activities	1,592	1,242
Investing Activities:
Business acquisitions, net of cash acquired	0	(345)
Property additions	(1,419)	(1,678)
Payments pursuant to LTSAs	(37)	(60)
Other investing activities	110	45
Net cash used for investing activities	(1,555)	(2,243)
Financing Activities:
Increase in notes payable	137	182
Proceeds —
Capital contributions from noncontrolling interests	73	313
Distributions to noncontrolling interests	(97)	(46)
Payment of common stock dividends	(702)	(678)
Other financing activities	(115)	(117)
Net cash provided from (used for) financing activities	(193)	1,734
Net Change in Cash, Cash Equivalents, and Restricted Cash	(156)	733
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	1,829	1,068
Cash, Cash Equivalents, and Restricted Cash at End of Period	1,673	1,801
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	515	519
Income taxes, net	(8)	(51)
Noncash transactions —
Contributions from noncontrolling interests	0	89
Contributions of wind turbine equipment	0	82
Accrued property additions at year-end	863	872
Reassessment of right-of-use assets under operating leases	40	0
Southern Power
Operating Activities:
Net income (loss)	27	65
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	126	125
Deferred income taxes	12	(8)
Amortization of investment tax credits	(15)	(15)
Gain on dispositions, net	(2)	(39)
Other, net	(3)	(4)
Changes in certain current assets and liabilities —
-Receivables	11	23
-Prepaid income taxes	(8)	16
-Other current assets	0	3
-Accounts payable	(21)	19
-Accrued taxes	7	5
-Other current liabilities	(17)	(3)
Net cash provided from operating activities	117	187
Investing Activities:
Business acquisitions, net of cash acquired	0	(345)
Property additions	(19)	(147)
Proceeds from dispositions	29	17
Change in construction payables	(31)	(7)
Payments pursuant to LTSAs	(15)	(27)
Other investing activities	(1)	5
Net cash used for investing activities	(37)	(504)
Financing Activities:
Increase (decrease) in notes payable, net	(3)
Increase in notes payable		140
Proceeds —
Senior notes	0	400
Return of capital to parent company	0	(271)
Capital contributions from noncontrolling interests	73	313
Distributions to noncontrolling interests	(97)	(46)
Payment of common stock dividends	(49)	(51)
Other financing activities	0	(7)
Net cash provided from (used for) financing activities	(76)	478
Net Change in Cash, Cash Equivalents, and Restricted Cash	4	161
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	135	182
Cash, Cash Equivalents, and Restricted Cash at End of Period	139	343
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	29	26
Income taxes, net	(8)	(2)
Noncash transactions —
Contributions from noncontrolling interests	0	89
Contributions of wind turbine equipment	0	82
Accrued property additions at year-end	46	60
Right-of-use assets obtained under operating leases	0	65
Reassessment of right-of-use assets under operating leases	$ 40	$ 0

Condensed Consolidated State_13

Condensed Consolidated Statements of Cash Flows (Unaudited) - SPC (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net cash paid for capitalized interest	$ 23	$ 21
Southern Power
Net cash paid for capitalized interest	$ 0	$ 1

Condensed Consolidated Balanc_3

Condensed Consolidated Balance Sheets (Unaudited) - SPC - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 1,662	$ 1,798
Receivables —
Customer accounts	2,006	1,806
Other accounts and notes	509	523
Materials and supplies	1,571	1,543
Other current assets	201	231
Total current assets	9,297	8,965
Property, Plant, and Equipment:
In service	116,259	115,592
Less: Accumulated depreciation	34,645	34,079
Plant in service, net of depreciation	81,614	81,513
Construction work in progress	9,337	8,771
Total property, plant, and equipment	91,790	91,108
Other Property and Investments:
Equity investments in unconsolidated subsidiaries	1,293	1,282
Total other property and investments	10,044	10,202
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,693	1,701
Other deferred charges and assets	1,898	1,776
Total deferred charges and other assets	17,508	17,259
Total Assets	128,639	127,534
Current Liabilities:
Securities due within one year	1,193	2,157
Notes payable	2,330	1,440
Accounts payable —
Accrued interest	404	533
Other current liabilities	1,105	872
Total current liabilities	10,434	10,921
Long-term Debt	50,633	50,120
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	9,506	8,862
Accumulated deferred ITCs	2,196	2,216
Operating lease obligations, deferred	1,521	1,503
Other deferred credits and liabilities	966	816
Total deferred credits and other liabilities	34,652	33,926
Total Liabilities	95,719	94,967
Total Stockholders' Equity (See accompanying statements)	32,629	32,276
Total Liabilities and Stockholders' Equity	128,639	127,534
Southern Power
Current Assets:
Cash and cash equivalents	130	107
Receivables —
Customer accounts	160	139
Affiliated	26	51
Other accounts and notes	21	29
Materials and supplies	108	106
Prepaid income taxes	468	27
Other current assets	49	46
Total current assets	962	505
Property, Plant, and Equipment:
In service	14,594	14,585
Less: Accumulated depreciation	3,341	3,241
Plant in service, net of depreciation	11,253	11,344
Construction work in progress	49	45
Total property, plant, and equipment	11,302	11,389
Other Property and Investments:
Intangible assets, net of amortization	278	282
Equity investments in unconsolidated subsidiaries	56	86
Net investment in sales-type leases	159	161
Total other property and investments	493	529
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	517	479
Prepaid LTSAs	219	210
Income taxes receivable, non-current	23	20
Other deferred charges and assets	250	258
Total deferred charges and other assets	1,009	967
Total Assets	13,766	13,390
Current Liabilities:
Securities due within one year	666	679
Notes payable	208	211
Accounts payable —
Affiliated	82	92
Other	67	85
Accrued taxes	21	14
Accrued interest	32	32
Other current liabilities	121	140
Total current liabilities	1,197	1,253
Long-term Debt	2,999	3,009
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	661	215
Accumulated deferred ITCs	1,600	1,614
Operating lease obligations, deferred	535	497
Other deferred credits and liabilities	218	204
Total deferred credits and other liabilities	3,014	2,530
Total Liabilities	7,210	6,792
Total Stockholders' Equity (See accompanying statements)	6,556	6,598
Total Liabilities and Stockholders' Equity	$ 13,766	$ 13,390

Condensed Consolidated Balanc_4

Condensed Consolidated Balance Sheets (Unaudited) - SPC (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Other intangible assets, amortization	$ 317	$ 307
SOUTHERN POWER CO
Other intangible assets, amortization	$ 114	$ 109

Condensed Consolidated State_14

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - SPC - USD ($) $ in Millions	Total	Paid-In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests	Southern Power	Southern PowerTotal Common Stockholders' Equity	Southern PowerPaid-In Capital	Southern PowerRetained Earnings (Accumulated Deficit)	Southern PowerAccumulated Other Comprehensive Income (Loss)	Southern PowerNoncontrolling Interests
Beginning 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	1,107					65	97		97		(32)
Return of capital to parent company						(271)	(271)	(271)
Other comprehensive income (loss)	28			28		16	16			16
Cash dividends on common stock	(678)		(678)			(51)	(51)		(51)
Capital contributions from noncontrolling interests	403				403	403					403
Distributions to noncontrolling interests	(46)				(46)	(46)					(46)
Other	1	2			(1)	(3)	(2)	(2)	1	(1)	(1)
Ending balance at Mar. 31, 2021	33,068	11,854	11,768	(367)	4,586	6,744	2,158	641	1,569	(52)	4,586
Beginning 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	991					27	72		72		(45)
Other comprehensive income (loss)	42			42		5	5			5
Cash dividends on common stock	(702)		(702)			(49)	(49)		(49)
Capital contributions from noncontrolling interests	73				73	73					73
Distributions to noncontrolling interests	(98)				(98)	(98)					(98)
Other	7	7	2
Ending balance at Mar. 31, 2022	$ 32,629	$ 11,994	$ 11,261	$ (195)	$ 4,332	$ 6,556	$ 2,224	$ 638	$ 1,608	$ (22)	$ 4,332

Condensed Consolidated State_15

Condensed Consolidated Statements of Income (Unaudited) - GAS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Revenues:
Total operating revenues	$ 6,648	$ 5,910
Operating Expenses:
Other operations and maintenance	1,516	1,372
Depreciation and amortization	892	871
Taxes other than income taxes	372	345
Total operating expenses	5,264	4,312
Operating Income	1,384	1,598
Other Income and (Expense):
Earnings from equity method investments	46	45
Interest expense, net of amounts capitalized	(462)	(450)
Other income (expense), net	145	58
Total other income and (expense)	(220)	(301)
Earnings Before Income Taxes	1,164	1,297
Income taxes (benefit)	173	190
Consolidated Net Income	991	1,107
Retail electric revenues
Operating Revenues:
Total operating revenues	3,613	3,342
Wholesale Electric
Operating Revenues:
Total operating revenues	664	545
Other electric revenues
Operating Revenues:
Total operating revenues	177	170
Natural Gas
Operating Revenues:
Total operating revenues	2,058	1,694
Natural gas
Operating Expenses:
Less Gross Gas Costs	1,095	583
Alternative revenue programs
Operating Revenues:
Total operating revenues	0	2
Other revenues
Operating Revenues:
Total operating revenues	136	159
Operating Expenses:
Less Gross Gas Costs	69	82
SOUTHERN Co GAS
Operating Revenues:
Total operating revenues	$ 2,058	$ 1,694
Operating Expenses:
Cost, Product and Service [Extensible Enumeration]	Natural gas	Natural gas
Other operations and maintenance	$ 305	$ 299
Depreciation and amortization	137	130
Taxes other than income taxes	100	81
Total operating expenses	1,637	1,093
Operating Income	421	601
Other Income and (Expense):
Earnings from equity method investments	40	41
Interest expense, net of amounts capitalized	(61)	(60)
Other income (expense), net	16	(63)
Total other income and (expense)	(5)	(82)
Earnings Before Income Taxes	416	519
Income taxes (benefit)	97	121
Consolidated Net Income	319	398
SOUTHERN Co GAS | Natural gas
Operating Revenues:
Total operating revenues	2,058	1,692
Operating Expenses:
Less Gross Gas Costs	1,095	583
SOUTHERN Co GAS | Alternative revenue programs
Operating Revenues:
Total operating revenues	$ 0	$ 2

Condensed Consolidated State_16

Condensed Consolidated Statements of Income (Unaudited) - GAS (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
SOUTHERN Co GAS
Revenue taxes collected	$ 71	$ 54

Condensed Consolidated State_17

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - GAS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net income	$ 991	$ 1,107
Qualifying hedges:
Changes in fair value, net of tax	19	(30)
Reclassification adjustment for amounts included in net income, net of tax	20	55
Total other comprehensive income	42	28
Comprehensive Income	1,033	1,135
SOUTHERN Co GAS
Net income	319	398
Qualifying hedges:
Changes in fair value, net of tax	26	1
Reclassification adjustment for amounts included in net income, net of tax	(6)	3
Total other comprehensive income	20	4
Comprehensive Income	$ 339	$ 402

Condensed Consolidated State_18

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - GAS (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Changes in fair value, tax	$ 8	$ (10)
Qualifying hedges, reclassification adjustment, tax	6	18
SOUTHERN Co GAS
Changes in fair value, tax	10	0
Qualifying hedges, reclassification adjustment, tax	$ (2)	$ 1

Condensed Consolidated State_19

Condensed Consolidated Statements of Cash Flows (Unaudited) - GAS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Operating Activities:
Net income (loss)	$ 991	$ 1,107
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	989	964
Deferred income taxes	40	140
Natural gas cost under recovery – long-term	162	(185)
Other, net	7	114
Changes in certain current assets and liabilities —
-Receivables	(217)	308
-Natural gas for sale, net of temporary LIFO liquidation	450	456
-Natural gas cost under recovery	(40)	(487)
-Other current assets	87	90
-Accounts payable	132	(216)
-Accrued taxes	(58)	(212)
-Other current liabilities	35	(63)
Net cash provided from operating activities	1,592	1,242
Investing Activities:
Property additions	(1,419)	(1,678)
Cost of removal, net of salvage	(227)	(85)
Change in construction payables, net	23	(116)
Other investing activities	110	45
Net cash used for investing activities	(1,555)	(2,243)
Proceeds —
Short-term borrowings	850	325
Redemptions and repurchases —
Short-term borrowings	(100)	(25)
Payment of common stock dividends	(702)	(678)
Net cash provided from (used for) financing activities	(193)	1,734
Net Change in Cash, Cash Equivalents, and Restricted Cash	(156)	733
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	1,829	1,068
Cash, Cash Equivalents, and Restricted Cash at End of Period	1,673	1,801
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	515	519
Income taxes, net	(8)	(51)
Noncash transactions —
Accrued property additions at year-end	863	872
SOUTHERN Co GAS
Operating Activities:
Net income (loss)	319	398
Adjustments to reconcile net income to net cash provided from operating activities —
Depreciation and amortization, total	137	130
Deferred income taxes	5	160
Mark-to-market adjustments	(38)	64
Natural gas cost under recovery – long-term	162	(185)
Other, net	41	5
Changes in certain current assets and liabilities —
-Receivables	(115)	74
-Natural gas for sale, net of temporary LIFO liquidation	450	456
-Prepaid income taxes	34	(51)
-Natural gas cost under recovery	(40)	(487)
-Other current assets	39	17
-Accounts payable	(23)	(7)
-Accrued taxes	54	10
-Other current liabilities	(1)	(34)
Net cash provided from operating activities	1,024	550
Investing Activities:
Property additions	(247)	(251)
Cost of removal, net of salvage	(20)	(16)
Change in construction payables, net	(5)	(47)
Other investing activities	1	6
Net cash used for investing activities	(271)	(308)
Financing Activities:
Increase (decrease) in notes payable, net	(577)	(127)
Proceeds —
Short-term borrowings	0	300
Redemptions and repurchases —
Short-term borrowings	(100)	0
Medium-term notes	0	(30)
Capital contributions from parent company	39	39
Payment of common stock dividends	(130)	(132)
Net cash provided from (used for) financing activities	(768)	50
Net Change in Cash, Cash Equivalents, and Restricted Cash	(15)	292
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	48	19
Cash, Cash Equivalents, and Restricted Cash at End of Period	33	311
Supplemental Cash Flow Information:
Interest, net of amounts capitalized	55	52
Income taxes, net	0	(1)
Noncash transactions —
Accrued property additions at year-end	$ 107	$ 95

Condensed Consolidated State_20

Condensed Consolidated Statements of Cash Flows (Unaudited) - GAS (Parenthetical) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Net cash paid for capitalized interest	$ 23	$ 21
SOUTHERN Co GAS
Net cash paid for capitalized interest	$ 2	$ 2

Condensed Consolidated Balanc_5

Condensed Consolidated Balance Sheets (Unaudited) - GAS - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Current Assets:
Cash and cash equivalents	$ 1,662	$ 1,798
Receivables —
Customer accounts	2,006	1,806
Unbilled revenues	638	711
Other accounts and notes	509	523
Accumulated provision for uncollectible accounts	(89)	(78)
Natural gas for sale	121	362
Prepaid expenses	739	330
Assets from risk management activities, net of collateral	405	151
Natural gas cost under recovery	306	266
Other regulatory assets	576	653
Other current assets	201	231
Total current assets	9,297	8,965
Property, Plant, and Equipment:
In service	116,259	115,592
Less: Accumulated depreciation	34,645	34,079
Plant in service, net of depreciation	81,614	81,513
Construction work in progress	9,337	8,771
Total property, plant, and equipment	91,790	91,108
Other Property and Investments:
Goodwill	5,280	5,280
Equity investments in unconsolidated subsidiaries	1,293	1,282
Other intangible assets, net of amortization	435	445
Miscellaneous property and investments	633	653
Total other property and investments	10,044	10,202
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,693	1,701
Prepaid pension costs	1,772	1,657
Other regulatory assets, deferred	5,372	5,577
Other deferred charges and assets	1,898	1,776
Total deferred charges and other assets	17,508	17,259
Total Assets	128,639	127,534
Current Liabilities:
Securities due within one year	1,193	2,157
Notes payable	2,330	1,440
Accounts payable —
Customer deposits	454	479
Accrued interest	404	533
Accrued compensation	574	1,070
Other regulatory liabilities	711	563
Other current liabilities	1,105	872
Total current liabilities	10,434	10,921
Long-term Debt	50,633	50,120
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	9,506	8,862
Deferred credits related to income taxes	5,365	5,401
Employee benefit obligations	1,526	1,550
Operating lease obligations, deferred	1,521	1,503
Other cost of removal obligations	2,030	2,103
Other deferred credits and liabilities	966	816
Total deferred credits and other liabilities	34,652	33,926
Total Liabilities	95,719	94,967
Common Stockholder's Equity (See accompanying statements)	32,629	32,276
Total Liabilities and Stockholders' Equity	128,639	127,534
SOUTHERN Co GAS
Current Assets:
Cash and cash equivalents	31	45
Receivables —
Customer accounts	603	462
Unbilled revenues	245	278
Other accounts and notes	52	49
Accumulated provision for uncollectible accounts	(51)	(39)
Natural gas for sale	121	362
Prepaid expenses	88	114
Assets from risk management activities, net of collateral	53	33
Natural gas cost under recovery	306	266
Other regulatory assets	104	136
Other current assets	47	49
Total current assets	1,599	1,755
Property, Plant, and Equipment:
In service	19,035	18,880
Less: Accumulated depreciation	5,159	5,067
Plant in service, net of depreciation	13,876	13,813
Construction work in progress	768	684
Total property, plant, and equipment	14,644	14,497
Other Property and Investments:
Goodwill	5,015	5,015
Equity investments in unconsolidated subsidiaries	1,178	1,173
Other intangible assets, net of amortization	34	37
Miscellaneous property and investments	19	19
Total other property and investments	6,246	6,244
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	67	70
Prepaid pension costs	183	175
Other regulatory assets, deferred	508	689
Other deferred charges and assets	130	130
Total deferred charges and other assets	888	1,064
Total Assets	23,377	23,560
Current Liabilities:
Securities due within one year	46	47
Notes payable	532	1,209
Accounts payable —
Affiliated	40	58
Other	349	361
Customer deposits	72	95
Accrued taxes	191	124
Accrued interest	68	59
Accrued compensation	66	110
Temporary LIFO liquidation	209	0
Other regulatory liabilities	72	8
Other current liabilities	140	155
Total current liabilities	1,785	2,226
Long-term Debt	6,814	6,855
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	1,568	1,555
Deferred credits related to income taxes	808	816
Employee benefit obligations	168	176
Operating lease obligations, deferred	58	59
Other cost of removal obligations	1,692	1,683
Accrued environmental remediation	189	197
Other deferred credits and liabilities	120	77
Total deferred credits and other liabilities	4,603	4,563
Total Liabilities	13,202	13,644
Common Stockholder's Equity (See accompanying statements)	10,175	9,916
Total Liabilities and Stockholders' Equity	$ 23,377	$ 23,560

Condensed Consolidated Balanc_6

Condensed Consolidated Balance Sheets (Unaudited) - GAS (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Other intangible assets, amortization	$ 317	$ 307
SOUTHERN Co GAS
Other intangible assets, amortization	$ 148	$ 145

Condensed Consolidated State_21

Condensed Consolidated Statements of Stockholders' Equity (Unaudited) - GAS - USD ($) $ in Millions	Total	Paid-In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	SOUTHERN Co GAS	SOUTHERN Co GASPaid-In Capital	SOUTHERN Co GASRetained Earnings (Accumulated Deficit)	SOUTHERN Co GASAccumulated Other Comprehensive Income (Loss)
Beginning 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	1,107				398		398
Capital contributions from parent company					57	57
Other comprehensive income (loss)	28			28	4			4
Cash dividends on common stock	(678)		(678)		(132)		(132)
Ending balance at Mar. 31, 2021	33,068	11,854	11,768	(367)	10,094	9,987	125	(18)
Beginning 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	991				319		319
Capital contributions from parent company					50	50
Other comprehensive income (loss)	42			42	20			20
Cash dividends on common stock	(702)		(702)		(130)		(130)
Ending balance at Mar. 31, 2022	$ 32,629	$ 11,994	$ 11,261	$ (195)	$ 10,175	$ 10,074	$ 57	$ 44

Introduction

Introduction	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Introduction	INTRODUCTION The condensed quarterly financial statements of each Registrant included herein have been prepared by such Registrant, without audit, pursuant to the rules and regulations of the SEC. The Condensed Balance Sheets at December 31, 2021 have been derived from the audited financial statements of each Registrant. In the opinion of each Registrant's management, the information regarding such Registrant furnished herein reflects all adjustments, which, except as otherwise disclosed, are of a normal recurring nature, necessary to present fairly the results of operations for the periods ended March 31, 2022 and 2021. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations, although each Registrant believes that the disclosures regarding such Registrant are adequate to make the information presented not misleading. Disclosures which would substantially duplicate the disclosures in the Form 10-K and details which have not changed significantly in amount or composition since the filing of the Form 10-K are generally omitted from this Quarterly Report on Form 10-Q unless specifically required by GAAP. Therefore, these Condensed Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the Form 10-K. Due to the seasonal variations in the demand for energy and other factors, operating results for the periods presented are not necessarily indicative of the operating results to be expected for the full year. Certain prior year data presented in the financial statements have been reclassified to conform to the current year presentation. These reclassifications had no impact on the overall results of operations, financial position, or cash flows of any Registrant. Goodwill and Other Intangible Assets Goodwill at March 31, 2022 and December 31, 2021 was as follows: Goodwill (in millions) Southern Company $ 5,280 Southern Company Gas: Gas distribution operations $ 4,034 Gas marketing services 981 Southern Company Gas total $ 5,015 Goodwill is not amortized, but is subject to an annual impairment test during the fourth quarter of each year, or more frequently if impairment indicators arise. Other intangible assets were as follows: At March 31, 2022 At December 31, 2021 Gross Carrying Amount Accumulated Amortization Other Gross Carrying Amount Accumulated Amortization Other (in millions) (in millions) Southern Company Other intangible assets subject to amortization: Customer relationships $ 212 $ (152) $ 60 $ 212 $ (150) $ 62 Trade names 64 (41) 23 64 (38) 26 PPA fair value adjustments 390 (114) 276 390 (109) 281 Other 11 (10) 1 11 (10) 1 Total other intangible assets subject to amortization $ 677 $ (317) $ 360 $ 677 $ (307) $ 370 Other intangible assets not subject to amortization: Federal Communications Commission licenses 75 — 75 75 — 75 Total other intangible assets $ 752 $ (317) $ 435 $ 752 $ (307) $ 445 Southern Power Other intangible assets subject to amortization: PPA fair value adjustments $ 390 $ (114) $ 276 $ 390 $ (109) $ 281 Southern Company Gas Other intangible assets subject to amortization: Gas marketing services Customer relationships $ 156 $ (132) $ 24 $ 156 $ (130) $ 26 Trade names 26 (16) 10 26 (15) 11 Total other intangible assets subject to amortization $ 182 $ (148) $ 34 $ 182 $ (145) $ 37 Amortization associated with other intangible assets was as follows: Three Months Ended March 31, 2022 (in millions) Southern Company (a) $ 10 Southern Power (b) 5 Southern Company Gas 3 (a) Includes $5 million recorded as a reduction to operating revenues. (b) Recorded as a reduction to operating revenues. Cash, Cash Equivalents, and Restricted Cash The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed balance sheets that total to the amount shown in the condensed statements of cash flows for the applicable Registrants: Southern Southern Southern March 31, 2022 December 31, 2021 March 31, 2022 December 31, 2021 March 31, 2022 December 31, 2021 (in millions) Cash and cash equivalents $ 1,662 $ 1,798 $ 130 $ 107 $ 31 $ 45 Restricted cash (a) : Other current assets 2 2 — — 2 2 Other deferred charges and assets 9 29 9 29 — — Total cash, cash equivalents, and restricted cash (b) $ 1,673 $ 1,829 $ 139 $ 135 $ 33 $ 48 (a) For Southern Power, restricted cash reflects $9 million and $10 million at March 31, 2022 and December 31, 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. For Southern Company Gas, reflects restricted cash held as collateral for workers' compensation, life insurance, and long-term disability insurance. (b) Total may not add due to rounding. Natural Gas for Sale With the exception of Nicor Gas, Southern Company Gas records natural gas inventories on a WACOG basis. For any declines in market prices below the WACOG considered to be other than temporary, an adjustment is recorded to reduce the value of natural gas inventories to market value. 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. Southern Company Gas recorded no material adjustments to natural gas inventories for either period presented. Nicor Gas' inventory decrement at March 31, 2022 is expected to be restored prior to year end. Depreciation and Amortization See Note 5 to the financial statements under "Depreciation and Amortization – Southern Power" in Item 8 of the Form 10-K for additional information. 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 the three months ended March 31, 2022 and is expected to result in an immaterial decrease in annual depreciation for 2022.

Regulatory Matters

Regulatory Matters	3 Months Ended
	Mar. 31, 2022
Regulated Operations [Abstract]
Regulatory Matters	REGULATORY MATTERS See Note 2 to the financial statements in Item 8 of the Form 10-K for additional information relating to regulatory matters. The recovery balances for certain retail regulatory clauses of the traditional electric operating companies and Southern Company Gas at March 31, 2022 and December 31, 2021 were as follows: Regulatory Clause Balance Sheet Line Item March 31, December 31, 2021 (in millions) Alabama Power Rate CNP Compliance Other regulatory assets, deferred $ 12 $ 16 Rate CNP PPA Other regulatory assets, deferred 84 84 Retail Energy Cost Recovery (*) Other regulatory assets, deferred 46 126 Georgia Power Fuel Cost Recovery Deferred under recovered fuel clause revenues $ 494 $ 410 Mississippi Power Fuel Cost Recovery Other customer accounts receivable $ 16 $ 4 Ad Valorem Tax Other regulatory assets, current 12 12 Other regulatory assets, deferred 33 37 Southern Company Gas Natural Gas Cost Recovery Natural gas cost under recovery $ 306 $ 266 Other regulatory assets, deferred 44 207 Other regulatory liabilities, current 13 — (*) 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. Alabama Power Certificate of Convenience and Necessity On March 25, 2022, the FERC approved Alabama Power's acquisition of the Calhoun Generating Station, which is expected to be completed by September 30, 2022. The completion of the acquisition remains subject to approval by the Alabama PSC. The ultimate outcome of this matter cannot be determined at this time. Georgia Power Rate Plan In 2020, the Georgia PSC denied a motion for reconsideration filed by the Sierra Club regarding the Georgia PSC's decision in the 2019 ARP allowing Georgia Power to recover compliance costs for CCR AROs. The Superior Court of Fulton County subsequently affirmed the Georgia PSC's decision and, in October 2021, the Georgia Court of Appeals affirmed the Superior Court of Fulton County's order. In December 2021, the Sierra Club filed a petition for writ of certiorari to the Georgia Supreme Court. The ultimate outcome of this matter cannot be determined at this time. See Note 6 to the financial statements in Item 8 of the Form 10-K for additional information regarding Georgia Power's AROs. Integrated Resource Plan In light of the ongoing supply chain challenges in the solar industry, Georgia Power amended the 970 MWs of utility-scale PPAs authorized in its 2019 Integrated Resource Plan to extend by one year the in-service dates for solar generation resources to the end of 2024. Nuclear Construction In 2009, the Georgia PSC certified construction of Plant Vogtle Units 3 and 4, in which Georgia Power holds a 45.7% ownership interest. In 2012, the NRC issued the related combined construction and operating licenses, which allowed full construction of the two AP1000 nuclear units (with electric generating capacity of approximately 1,100 MWs each) and related facilities to begin. Until March 2017, construction on Plant Vogtle Units 3 and 4 continued under the Vogtle 3 and 4 Agreement, which was a substantially fixed price agreement. In connection with the EPC Contractor's bankruptcy filing in March 2017, Georgia Power, acting for itself and as agent for the other Vogtle Owners, entered into several transitional arrangements to allow construction to continue. In July 2017, Georgia Power, acting for itself and as agent for the other Vogtle Owners, entered into the Vogtle Services Agreement, whereby Westinghouse provides facility design and engineering services, procurement and technical support, and staff augmentation on a time and materials cost basis. The Vogtle Services Agreement provides that it will continue until the start-up and testing of Plant Vogtle Units 3 and 4 are complete and electricity is generated and sold from both units. The Vogtle Services Agreement is terminable by the Vogtle Owners upon 30 days' written notice. In October 2017, Georgia Power, acting for itself and as agent for the other Vogtle Owners, executed the Bechtel Agreement, a cost reimbursable plus fee arrangement, whereby Bechtel is reimbursed for actual costs plus a base fee and an at-risk fee, which is subject to adjustment based on Bechtel's performance against cost and schedule targets. Each Vogtle Owner is severally (not jointly) liable for its proportionate share, based on its ownership interest, of all amounts owed to Bechtel under the Bechtel Agreement. The Vogtle Owners may terminate the Bechtel Agreement at any time for their convenience, provided that the Vogtle Owners will be required to pay amounts related to work performed prior to the termination (including the applicable portion of the base fee), certain termination-related costs, and, at certain stages of the work, the applicable portion of the at-risk fee. Bechtel may terminate the Bechtel Agreement under certain circumstances, including certain Vogtle Owner suspensions of work, certain breaches of the Bechtel Agreement by the Vogtle Owners, Vogtle Owner insolvency, and certain other events. See Note 8 to the financial statements under "Long-term Debt – DOE Loan Guarantee Borrowings" in Item 8 of the Form 10-K for information on the Amended and Restated Loan Guarantee Agreement, including applicable covenants, events of default, and mandatory prepayment events. 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 first quarter 2023 and the fourth quarter 2023, respectively, is as follows: (in millions) Base project capital cost forecast (a)(b) $ 10,294 Construction contingency estimate 107 Total project capital cost forecast (a)(b) 10,401 Net investment at March 31, 2022 (b) (8,715) Remaining estimate to complete $ 1,686 (a) Includes approximately $590 million of costs that are not shared with the other Vogtle Owners and approximately $440 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 $377 million, of which $221 million had been accrued through March 31, 2022. (b) Net of $1.7 billion received from Toshiba under the Guarantee Settlement Agreement and approximately $188 million in related customer refunds. Georgia Power estimates that its financing costs for construction of Plant Vogtle Units 3 and 4 will total approximately $3.4 billion, of which $3.0 billion had been incurred through March 31, 2022. As part of its ongoing processes, Southern Nuclear continues to evaluate cost and schedule forecasts on a regular basis to incorporate current information available, particularly in the areas of engineering support, commodity installation, system turnovers and related test results, and workforce statistics. Southern Nuclear establishes aggressive target values for monthly construction production and system turnover activities, which are reflected in the site work plans. Since March 2020, the number of active COVID-19 cases at the site has fluctuated consistent with the surrounding area and impacted productivity levels and pace of activity completion, with the site experiencing peaks in the number of active cases in January 2021, August 2021, and January 2022. Georgia Power estimates the productivity impacts of the COVID-19 pandemic have consumed approximately three Fuel load for Unit 3 is projected during the third quarter or the fourth quarter 2022 with an in-service date projected during the fourth quarter 2022 or the first quarter 2023. Unit 3's projected schedule primarily depends on improvements in overall construction productivity and production levels, the volume and completion of construction remediation work, completion of work packages, including inspection records, and other documentation necessary to submit the remaining ITAACs and begin fuel load, the pace of system and area turnovers, and the progression of startup and other testing. An in-service date during the third quarter or the fourth quarter 2023 for Unit 4 is projected. Unit 4's projected schedule primarily depends on overall construction productivity and production levels improving as well as appropriate levels of craft laborers, particularly electricians and pipefitters, being added and maintained. Any further delays could result in later in-service dates. During the first quarter 2022, established construction contingency totaling $43 million was assigned to the base capital cost forecast for costs primarily associated with construction productivity, the pace of system turnovers, and support resources for Units 3 and 4. As Unit 3 completes system turnover from construction and moves to testing and transition to operations, ongoing and potential future challenges include construction productivity, completion of construction remediation work, completion of work packages, including inspection records, and other documentation necessary to submit the remaining ITAACs and begin fuel load, and final component and pre-operational tests. As Unit 4 progresses through construction and continues to transition into testing, ongoing and potential future challenges include the pace and quality of electrical installation; availability of craft and supervisory resources, including the temporary diversion of such resources to support Unit 3 construction efforts; the pace of work package closures and system turnovers; and the timeframe and duration of hot functional and other testing. As construction, including subcontract work, continues on both Units 3 and 4, ongoing or future challenges include management of contractors and vendors; subcontractor performance; supervision of craft labor and related productivity, particularly in the installation of electrical, mechanical, and instrumentation and controls commodities, ability to attract and retain craft labor, and/or related cost escalation; and procurement and related installation. New challenges may arise, particularly as Units 3 and 4 move into initial testing and start-up, which may result in required engineering changes or remediation related to plant systems, structures, or components (some of which are based on new technology that only within the last few years began initial operation in the global nuclear industry at this scale). The ongoing and potential future challenges described above may change the projected schedule and estimated cost. There have been technical and procedural challenges to the construction and licensing of Plant Vogtle Units 3 and 4 at the federal and state level and additional challenges may arise. In addition, certain license amendment requests have been filed and approved or are pending before the NRC. Processes are in place that are designed to ensure compliance with the requirements specified in the Westinghouse Design Control Document and the combined construction and operating licenses, including inspections by Southern Nuclear and the NRC that occur throughout construction. In connection with the additional construction remediation work described above, Southern Nuclear reviewed the project's construction quality programs and, where needed, is implementing improvement plans consistent with these processes. On March 25, 2022, the NRC completed its follow-up inspection related to the November 2021 final significance report on its special inspection to review the root cause of this additional construction remediation work and the corresponding corrective action plans. The NRC closed the two white findings identified in November 2021 and returned Vogtle Unit 3 to the NRC's baseline inspection program. Various design and other licensing-based compliance matters, including the timely submittal by Southern Nuclear of the ITAAC documentation for each unit and the related reviews and approvals by the NRC necessary to support NRC authorization to load fuel, have arisen or may arise, which may result in additional license amendments or require other resolution. If any license amendment requests or other licensing-based compliance issues, including inspections and ITAACs, are not resolved in a timely manner, there may be delays in the project schedule that could result in increased costs. The ultimate outcome of these matters cannot be determined at this time. However, any extension of the in-service date beyond the first quarter 2023 for Unit 3 or the fourth quarter 2023 for Unit 4, including the current level of cost sharing described below, is estimated to result in additional base capital costs for Georgia Power of up to $60 million per month for Unit 3 and $40 million per month for Unit 4, as well as the related AFUDC and any additional related construction, support resources, or testing costs. While Georgia Power is not precluded from seeking retail recovery of any future capital cost forecast increase other than the amounts related to the cost-sharing and tender provisions of the joint ownership agreements described below, management will ultimately determine whether or not to seek recovery. Any further changes to the capital cost forecast that are not expected to be recoverable through regulated rates will be required to be charged to income and such charges could be material. Joint Owner Contracts In November 2017, the Vogtle Owners entered into an amendment to their joint ownership agreements for Plant Vogtle Units 3 and 4 to provide for, among other conditions, additional Vogtle Owner approval requirements. Effective in August 2018, the Vogtle Owners further amended the joint ownership agreements to clarify and provide procedures for certain provisions of the joint ownership agreements related to adverse events that require the vote of the holders of at least 90% of the ownership interests in Plant Vogtle Units 3 and 4 to continue construction (as amended, and together with the November 2017 amendment, the Vogtle Joint Ownership Agreements). The Vogtle Joint Ownership Agreements also confirm that the Vogtle Owners' sole recourse against Georgia Power or Southern Nuclear for any action or inaction in connection with their performance as agent for the Vogtle Owners is limited to removal of Georgia Power and/or Southern Nuclear as agent, except in cases of willful misconduct. Amendments to the Vogtle Joint Ownership Agreements In connection with a September 2018 vote by the Vogtle Owners to continue construction, Georgia Power entered into (i) a binding term sheet (Vogtle Owner Term Sheet) with the other Vogtle Owners and MEAG Power's wholly-owned subsidiaries MEAG Power SPVJ, LLC (MEAG SPVJ), MEAG Power SPVM, LLC (MEAG SPVM), and MEAG Power SPVP, LLC (MEAG SPVP) to take certain actions which partially mitigate potential financial exposure for the other Vogtle Owners, including additional amendments to the Vogtle Joint Ownership Agreements and the purchase of PTCs from the other Vogtle Owners at pre-established prices, and (ii) a term sheet (MEAG Term Sheet) with MEAG Power and MEAG SPVJ to provide up to $300 million of funding with respect to MEAG SPVJ's ownership interest in Plant Vogtle Units 3 and 4 under certain circumstances. In January 2019, Georgia Power, MEAG Power, and MEAG SPVJ entered into an agreement to implement the provisions of the MEAG Term Sheet. In February 2019, Georgia Power, the other Vogtle Owners, and MEAG Power's wholly-owned subsidiaries MEAG SPVJ, MEAG SPVM, and MEAG SPVP entered into certain amendments to the Vogtle Joint Ownership Agreements to implement the provisions of the Vogtle Owner Term Sheet (Global Amendments). Pursuant to the Global Amendments: (i) each Vogtle Owner must pay its proportionate share of qualifying construction costs for Plant Vogtle Units 3 and 4 based on its ownership percentage up to the estimated cost at completion (EAC) for Plant Vogtle Units 3 and 4 which formed the basis of Georgia Power's forecast of $8.4 billion in the nineteenth VCM plus $800 million; (ii) Georgia Power will be responsible for 55.7% of actual qualifying construction costs between $800 million and $1.6 billion over the EAC in the nineteenth VCM (resulting in $80 million of potential additional costs to Georgia Power), with the remaining Vogtle Owners responsible for 44.3% of such costs pro rata in accordance with their respective ownership interests; and (iii) Georgia Power will be responsible for 65.7% of qualifying construction costs between $1.6 billion and $2.1 billion over the EAC in the nineteenth VCM (resulting in a further $100 million of potential additional costs to Georgia Power), with the remaining Vogtle Owners responsible for 34.3% of such costs pro rata in accordance with their respective ownership interests. If the EAC is revised and exceeds the EAC in the nineteenth VCM by more than $2.1 billion, each of the other Vogtle Owners will have a one-time option at the time the project budget cost forecast is so revised to tender a portion of its ownership interest to Georgia Power in exchange for Georgia Power's agreement to pay 100% of such Vogtle Owner's remaining share of total construction costs in excess of the EAC in the nineteenth VCM plus $2.1 billion. For purposes of the foregoing provisions, qualifying construction costs will not include costs (i) resulting from force majeure events, including epidemics and quarantines, governmental actions or inactions (or significant delays associated with issuance of such actions) that affect the licensing, completion, start-up, operations, or financing of Plant Vogtle Units 3 and 4, administrative proceedings or litigation regarding ITAAC or other regulatory challenges to commencement of operation of Plant Vogtle Units 3 and 4, and changes in laws or regulations governing Plant Vogtle Units 3 and 4, (ii) legal fees and legal expenses incurred due to litigation with contractors or subcontractors that are not subsidiaries or affiliates of Southern Company, and (iii) additional costs caused by requests from the Vogtle Owners other than Georgia Power, except for the exercise of a right to vote granted under the Vogtle Joint Ownership Agreements, that increase costs by $100,000 or more. In addition, pursuant to the Global Amendments, the holders of at least 90% of the ownership interests in Plant Vogtle Units 3 and 4 must vote to continue construction if certain adverse events occur, including, among other events: (i) the bankruptcy of Toshiba; (ii) the termination or rejection in bankruptcy of certain agreements, including the Vogtle Services Agreement, the Bechtel Agreement, or the agency agreement with Southern Nuclear; (iii) Georgia Power's public announcement of its intention not to submit for rate recovery any portion of its investment in Plant Vogtle Units 3 and 4 or the Georgia PSC determines that any of Georgia Power's costs relating to the construction of Plant Vogtle Units 3 and 4 will not be recovered in retail rates, excluding any additional amounts paid by Georgia Power on behalf of the other Vogtle Owners pursuant to the Global Amendments described above and the first 6% of costs during any six-month VCM reporting period that are disallowed by the Georgia PSC for recovery, or for which Georgia Power elects not to seek cost recovery, through retail rates; and (iv) an incremental extension of one year or more from the seventeenth VCM report estimated in-service dates of November 2021 and November 2022 for Units 3 and 4, respectively. The schedule extension announced in February 2022 triggered the requirement for a vote to continue construction. Effective February 25, 2022, all of the Vogtle Owners had voted to continue construction. Georgia Power and the other Vogtle Owners do not agree on either the starting dollar amount for the determination of cost increases subject to the cost-sharing and tender provisions of the Global Amendments or the extent to which COVID-19-related costs impact those provisions. Based on the definition in the Global Amendments, Georgia Power believes the starting dollar amount is $18.38 billion and the current project capital cost forecast exceeds the cost-sharing provision threshold, but not the tender provision threshold. The other Vogtle Owners have notified Georgia Power that they believe the current project capital cost forecast exceeds the cost-sharing thresholds and triggers the tender provisions under the Global Amendments. Georgia Power recorded a pre-tax charge to income in the fourth quarter 2021 of approximately $440 million ($328 million after tax) associated with these cost-sharing and tender provisions, which is included in the total project capital cost forecast. Georgia Power may be required to record further pre-tax charges to income of up to approximately $460 million associated with these provisions based on the current project capital cost forecast. Georgia Power's incremental charges associated with these provisions, which relate to the other Vogtle Owners' share of costs, will not be recovered from retail customers. In October 2021, Georgia Power and the other Vogtle Owners entered into an agreement to clarify the process for the tender provisions of the Global Amendments to provide for a decision between 120 and 180 days after the tender option is triggered, which the other Vogtle Owners assert occurred on February 14, 2022. Georgia Power's ownership interest in Plant Vogtle Units 3 and 4 continues to be 45.7%; however, it could increase if one or more of the other Vogtle Owners exercise the option to tender a portion of their ownership interest to Georgia Power and require Georgia Power to pay 100% of the remaining share of the costs necessary to complete Plant Vogtle Units 3 and 4. Georgia Power's incremental ownership interest would be calculated and conveyed to Georgia Power after Plant Vogtle Units 3 and 4 are placed in service. The ultimate outcome of these matters cannot be determined at this time. Regulatory Matters In 2009, the Georgia PSC voted to certify construction of Plant Vogtle Units 3 and 4 with a certified capital cost of $4.418 billion. In addition, in 2009 the Georgia PSC approved inclusion of the Plant Vogtle Units 3 and 4 related CWIP accounts in rate base, and the State of Georgia enacted the Georgia Nuclear Energy Financing Act, which allows Georgia Power to recover financing costs for Plant Vogtle Units 3 and 4. Financing costs are recovered on all applicable certified costs through annual adjustments to the NCCR tariff up to the certified capital cost of $4.418 billion. At March 31, 2022, Georgia Power had recovered approximately $2.8 billion of financing costs. Financing costs related to capital costs above $4.418 billion are being recognized through AFUDC and are expected to be recovered through retail rates over the life of Plant Vogtle Units 3 and 4; however, Georgia Power is not recording AFUDC related to any capital costs in excess of the total deemed reasonable by the Georgia PSC (currently $7.3 billion) and not requested for rate recovery. In November 2021, the Georgia PSC approved Georgia Power's request to decrease the NCCR tariff by $78 million annually, effective January 1, 2022. Georgia Power is required to file semi-annual VCM reports with the Georgia PSC by February 28 and August 31 of each year. In 2013, in connection with the eighth VCM report, the Georgia PSC approved a stipulation between Georgia Power and the staff of the Georgia PSC to waive the requirement to amend the Plant Vogtle Units 3 and 4 certificate in accordance with the 2009 certification order until the completion of Plant Vogtle Unit 3, or earlier if deemed appropriate by the Georgia PSC and Georgia Power. In 2016, the Georgia PSC voted to approve a settlement agreement (Vogtle Cost Settlement Agreement) resolving certain prudency matters in connection with the fifteenth VCM report. In December 2017, the Georgia PSC voted to approve (and issued its related order on January 11, 2018) Georgia Power's seventeenth VCM report and modified the Vogtle Cost Settlement Agreement. The Vogtle Cost Settlement Agreement, as modified by the January 11, 2018 order, resolved the following regulatory matters related to Plant Vogtle Units 3 and 4: (i) none of the $3.3 billion of costs incurred through December 31, 2015 and reflected in the fourteenth VCM report should be disallowed from rate base on the basis of imprudence; (ii) the Contractor Settlement Agreement was reasonable and prudent and none of the $0.3 billion paid pursuant to the Contractor Settlement Agreement should be disallowed from rate base on the basis of imprudence; (iii) (a) capital costs incurred up to $5.68 billion would be presumed to be reasonable and prudent with the burden of proof on any party challenging such costs, (b) Georgia Power would have the burden to show that any capital costs above $5.68 billion were prudent, and (c) a revised capital cost forecast of $7.3 billion (after reflecting the impact of payments received under the Guarantee Settlement Agreement and related customer refunds) was found reasonable; (iv) construction of Plant Vogtle Units 3 and 4 should be completed, with Southern Nuclear serving as project manager and Bechtel as primary contractor; (v) approved and deemed reasonable Georgia Power's revised schedule placing Plant Vogtle Units 3 and 4 in service in November 2021 and November 2022, respectively; (vi) confirmed that the revised cost forecast does not represent a cost cap and that a prudence proceeding on cost recovery will occur following Unit 4 fuel load, consistent with applicable Georgia law; (vii) reduced the ROE used to calculate the NCCR tariff (a) from 10.95% (the ROE rate setting point authorized by the Georgia PSC in the 2013 alternate rate plan) to 10.00% effective January 1, 2016, (b) from 10.00% to 8.30%, effective January 1, 2020, and (c) from 8.30% to 5.30%, effective January 1, 2021 (provided that the ROE in no case will be less than Georgia Power's average cost of long-term debt); (viii) reduced the ROE used for AFUDC equity for Plant Vogtle Units 3 and 4 from 10.00% to Georgia Power's average cost of long-term debt, effective January 1, 2018; and (ix) agreed that effective the first month after Unit 3 reaches commercial operation, retail base rates would be adjusted to include the costs related to Unit 3 and common facilities deemed prudent in the Vogtle Cost Settlement Agreement (see Note 2 to the financial statements under "Georgia Power – Plant Vogtle Unit 3 and Common Facilities Rate Proceeding" in Item 8 of the Form 10-K for additional information). The January 11, 2018 order also stated that if Plant Vogtle Units 3 and 4 are not commercially operational by June 1, 2021 and June 1, 2022, respectively, the ROE used to calculate the NCCR tariff will be further reduced by 10 basis points each month (but not lower than Georgia Power's average cost of long-term debt) until the respective Unit is commercially operational. The ROE reductions negatively impacted earnings by approximately $270 million in 2021 and are estimated to have negative earnings impacts of approximately $300 million and $265 million in 2022 and 2023, respectively. In its January 11, 2018 order, the Georgia PSC also stated if other conditions change and assumptions upon which Georgia Power's seventeenth VCM report are based do not materialize, the Georgia PSC reserved the right to reconsider the decision to continue construction. In the August 2021 order approving the twenty-fourth VCM report, the Georgia PSC approved a stipulation addressing the following matters: (i) beginning with its twenty-fifth VCM report, Georgia Power will continue to report to the Georgia PSC all costs incurred during the period for review and will request for approval costs up to the $7.3 billion determined to be reasonable in the Georgia PSC's seventeenth VCM order and (ii) Georgia Power will not seek rate recovery of the $0.7 billion increase to the base capital cost forecast included in the nineteenth VCM report and charged to income by Georgia Power in the second quarter 2018. In addition, the stipulation confirms Georgia Power may request verification and approval of costs above $7.3 billion for inclusion in rate base at a later time, but no earlier than the prudence review contemplated by the seventeenth VCM order described previously. The Georgia PSC has approved 25 VCM reports covering periods through June 30, 2021. These reports reflect total construction capital costs incurred of $7.9 billion (net of $1.7 billion of payments received under the Guarantee Settlement Agreement and approximately $188 million in related customer refunds), of which the Georgia PSC has verified and approved $7.3 billion as described above. Georgia Power filed its twenty-sixth VCM report with the Georgia PSC on February 17, 2022, reflecting $584 million of additional construction capital costs incurred through December 31, 2021 and the total capital cost forecast described above. The ultimate outcome of these matters cannot be determined at this time. Mississippi Power Performance Evaluation Plan On March 15, 2022, Mississippi Power submitted its annual retail PEP filing for 2022 to the Mississippi PSC, which requested a 1.9%, or approximately $18 million, annual increase in revenues, primarily due to increases in investment, operations and maintenance expenses, and depreciation and amortization. In accordance with the PEP rate schedule, the rate increase became effective with the first billing cycle of April 2022, subject to refund. The related proceedings are expected to conclude in summer 2022; however, the ultimate outcome of this matter cannot be determined at this time. Ad Valorem Tax Adjustment On April 13, 2022, Mississippi Power submitted its annual ad valorem tax adjustment filing for 2022, which requested a $5 million annual increase in revenues. The ultimate outcome of this matter cannot be determined at this time. Southern Company Gas Infrastructure Replacement Programs and Capital Projects Capital expenditures incurred under specific infrastructure replacement programs and capital projects during the first three months of 2022 were as follows: Utility Program Three Months Ended March 31, 2022 (in millions) Nicor Gas Investing in Illinois $ 51 Virginia Natural Gas Steps to Advance Virginia's Energy 14 Atlanta Gas Light System Reinforcement Rider 14 Chattanooga Gas Pipeline Replacement Program 1 Total $ 80

Contingencies

Contingencies	3 Months Ended
	Mar. 31, 2022
Commitments and Contingencies Disclosure [Abstract]
Contingencies	CONTINGENCIESSee Note 3 to the financial statements in Item 8 of the Form 10-K for information relating to various lawsuits and other contingencies. 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. Southern Company In February 2017, Jean Vineyard and Judy Mesirov each filed a shareholder derivative lawsuit in the U.S. District Court for the Northern District of Georgia. Each of these lawsuits names as defendants Southern Company, certain of its directors, certain of its current and former officers, and certain former Mississippi Power officers. In 2017, these two shareholder derivative lawsuits were consolidated in the U.S. District Court for the Northern District of Georgia. The complaints allege that the defendants caused Southern Company to make false or misleading statements regarding the Kemper County energy facility cost and schedule. Further, the complaints allege that the defendants were unjustly enriched and caused the waste of corporate assets and also allege that the individual defendants violated their fiduciary duties. In May 2017, Helen E. Piper Survivor's Trust filed a shareholder derivative lawsuit in the Superior Court of Gwinnett County, Georgia that names as defendants Southern Company, certain of its directors, certain of its current and former officers, and certain former Mississippi Power officers. The complaint alleges that the individual defendants, among other things, breached their fiduciary duties in connection with schedule delays and cost overruns associated with the construction of the Kemper County energy facility. The complaint further alleges that the individual defendants authorized or failed to correct false and misleading statements regarding the Kemper County energy facility schedule and cost and failed to implement necessary internal controls to prevent harm to Southern Company. In August 2019, the court granted a motion filed by the plaintiff in July 2019 to substitute a new named plaintiff, Martin J. Kobuck, in place of Helen E. Piper Survivor's Trust. The plaintiffs in each of these cases seek to recover, on behalf of Southern Company, unspecified actual damages and, on each plaintiff's own behalf, attorneys' fees and costs in bringing the lawsuit. The plaintiffs also seek certain changes to Southern Company's corporate governance and internal processes. On January 21, 2022, the plaintiffs in the federal court action filed a motion for preliminary approval of settlement, together with an executed stipulation of settlement, which applies to both actions. On March 11, 2022, the U.S. District Court for the Northern District of Georgia entered an order preliminarily approving the settlement. The proposed settlement consists of an aggregate payment by Southern Company's insurers of approximately $4.5 million for attorneys' fees and expenses, as well as adoption of various corporate governance reforms by Southern Company. The terms of the proposed settlement and the corporate governance reforms remain subject to final approval by the court. Georgia Power 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. 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. In July 2020, a group of individual plaintiffs filed a complaint in the Superior Court of Fulton County, Georgia against Georgia Power alleging that releases from Plant Scherer have impacted groundwater, surface water, 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. In October 2021, three 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, Georgia Power filed a notice to remove the three cases pending in the Superior Court of Monroe County, Georgia to the U.S. District Court for the Middle District of Georgia. On February 7, 2022, four additional complaints were filed in the Superior Court of Monroe County, Georgia against Georgia Power seeking damages for alleged personal injuries or property damage. On March 9, 2022, Georgia Power filed a notice to remove the four cases pending in the Superior Court of Monroe 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. The appellate court remanded the case to the U.S. District Court for the Southern District of Mississippi for further proceedings. The appellate court's decision is not final until the opportunity for rehearing en banc is resolved. 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 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. These regulatory mechanisms are adjusted annually or as necessary within limits approved by the state PSCs or other applicable state regulatory agencies. Georgia Power's environmental remediation liability was $16 million and $17 million at March 31, 2022 and December 31, 2021, respectively. 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. Southern Company Gas' environmental remediation liability was $249 million at both March 31, 2022 and December 31, 2021 based on the estimated cost of environmental investigation and remediation associated with known former manufactured gas plant operating sites. 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.

Revenue from Contracts with Cus

Revenue from Contracts with Customers and Lease Income	3 Months Ended
	Mar. 31, 2022
Revenue from Contract with Customer [Abstract]
Revenue from Contracts with Customers and Lease Income	REVENUE FROM CONTRACTS WITH CUSTOMERS AND LEASE INCOME 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 to the financial statements under "Revenues" in Item 8 of the Form 10-K for additional information on the revenue policies of the Registrants. See "Lease Income" herein and Note (J) 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 three months ended March 31, 2022 and 2021: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Three Months Ended March 31, 2022 Operating revenues Retail electric revenues Residential $ 1,525 $ 634 $ 821 $ 70 $ — $ — Commercial 1,178 375 738 65 — — Industrial 727 323 334 70 — — Other 26 4 20 2 — — Total retail electric revenues 3,456 1,336 1,913 207 — — Natural gas distribution revenues Residential 1,016 — — — — 1,016 Commercial 270 — — — — 270 Transportation 337 — — — — 337 Industrial 32 — — — — 32 Other 129 — — — — 129 Total natural gas distribution revenues 1,784 — — — — 1,784 Wholesale electric revenues PPA energy revenues 342 59 32 3 251 — PPA capacity revenues 134 39 12 3 81 — Non-PPA revenues 58 64 9 102 73 — Total wholesale electric revenues 534 162 53 108 405 — Other natural gas revenues Gas marketing services 243 — — — — 243 Other natural gas revenues 16 — — — — 16 Total natural gas revenues 259 — — — — 259 Other revenues 225 48 95 9 8 — Total revenue from contracts with customers 6,258 1,546 2,061 324 413 2,043 Other revenue sources (a) 390 103 147 11 126 15 Total operating revenues $ 6,648 $ 1,649 $ 2,208 $ 335 $ 539 $ 2,058 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Three Months Ended March 31, 2021 Operating revenues Retail electric revenues Residential $ 1,468 $ 628 $ 776 $ 64 $ — $ — Commercial 1,117 372 686 59 — — Industrial 668 320 284 64 — — Other 24 5 17 2 — — Total retail electric revenues 3,277 1,325 1,763 189 — — Natural gas distribution revenues Residential 614 — — — — 614 Commercial 170 — — — — 170 Transportation 288 — — — — 288 Industrial 16 — — — — 16 Other 97 — — — — 97 Total natural gas distribution revenues 1,185 — — — — 1,185 Wholesale electric revenues PPA energy revenues 212 43 13 4 156 — PPA capacity revenues 119 29 13 3 75 — Non-PPA revenues 67 32 9 88 61 — Total wholesale electric revenues 398 104 35 95 292 — Other natural gas revenues Wholesale gas services 1,590 — — — — 1,590 Gas marketing services 194 — — — — 194 Other natural gas revenues 7 — — — — 7 Total natural gas revenues 1,791 — — — — 1,791 Other revenues 249 46 113 8 4 — Total revenue from contracts with customers 6,900 1,475 1,911 292 296 2,976 Other revenue sources (a) 1,306 84 59 15 144 1,014 Other adjustments (b) (2,296) — — — — (2,296) Total operating revenues $ 5,910 $ 1,559 $ 1,970 $ 307 $ 440 $ 1,694 (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 Note 15 to the financial statements under "Southern Company Gas" in Item 8 of the Form 10-K and Note (L) 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 March 31, 2022 and December 31, 2021: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Accounts Receivable At March 31, 2022 $ 2,571 $ 616 $ 695 $ 85 $ 128 $ 865 At December 31, 2021 2,504 589 736 73 149 753 Contract Assets At March 31, 2022 $ 81 $ 2 $ 31 $ — $ — $ — At December 31, 2021 117 2 63 — 1 — Contract Liabilities At March 31, 2022 $ 72 $ 3 $ 13 $ 2 $ 1 $ — At December 31, 2021 57 4 14 — 1 — At March 31, 2022 and December 31, 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 $47 million and $50 million of contract assets and $54 million and $39 million of contract liabilities at March 31, 2022 and December 31, 2021, respectively, for outstanding performance obligations. Revenues recognized in the three months ended March 31, 2022, which were included in contract liabilities at December 31, 2021, were immaterial for all 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. 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 March 31, 2022 are expected to be recognized as follows: 2022 (remaining) 2023 2024 2025 2026 Thereafter (in millions) Southern Company $ 529 $ 459 $ 351 $ 321 $ 307 $ 2,345 Alabama Power 24 24 7 5 — — Georgia Power 55 55 26 22 11 21 Southern Power 252 294 310 294 299 2,339 Revenue expected to be recognized for performance obligations remaining at March 31, 2022 w as immaterial for Mississippi Power and Southern Company Gas. Lease Income Lease income for the three months ended March 31, 2022 and 2021 is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) For the Three Months Ended March 31, 2022 Lease income - interest income on sales-type leases $ 6 $ — $ — $ 4 $ 2 $ — Lease income - operating leases 51 20 8 — 21 9 Variable lease income 84 — — — 90 — Total lease income $ 141 $ 20 $ 8 $ 4 $ 113 $ 9 For the Three Months Ended March 31, 2021 Lease income - interest income on sales-type leases $ 3 $ — $ — $ 3 $ — $ — Lease income - operating leases 55 21 10 — 21 9 Variable lease income 84 — — — 90 — Total lease income $ 142 $ 21 $ 10 $ 3 $ 111 $ 9 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.

Consolidated Entities and Equit

Consolidated Entities and Equity Method Investments	3 Months Ended
	Mar. 31, 2022
Regulated Operations [Abstract]
Consolidated Entities and Equity Method Investments	CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTSSee Note 7 to the financial statements in Item 8 of the Form 10-K for additional information. 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 At March 31, 2022 and December 31, 2021, SP Solar had total assets of $6.0 billion and $6.1 billion, respectively, total liabilities of $407 million and $408 million, respectively, 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. At March 31, 2022 and December 31, 2021, SP Wind had total assets of $2.3 billion, total liabilities of $180 million and $130 million, respectively, and noncontrolling interests of $41 million. 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 March 31, 2022 and December 31, 2021, the other VIEs had total assets of $1.8 billion and $1.9 billion, respectively, total liabilities of $248 million and $263 million, respectively, and noncontrolling interests of $876 million and $886 million, 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 March 31, 2022 and December 31, 2021, Southern Power had equity method investments in wind and battery energy storage projects totaling $56 million and $86 million, respectively. Earnings (loss) from these investments were immaterial for both periods presented. During the first quarter 2022, Southern Power sold an equity method investment in a wind project and received proceeds of $31 million. The gain associated with the transaction was immaterial. Southern Company Gas Equity Method Investments The carrying amounts of Southern Company Gas' equity method investments at March 31, 2022 and December 31, 2021 and related earnings from those investments for the three months ended March 31, 2022 and 2021 were as follows: Investment Balance March 31, 2022 December 31, 2021 (in millions) SNG $ 1,138 $ 1,129 Other (*) 40 44 Total $ 1,178 $ 1,173 (*) Balance at March 31, 2022 reflects a $4 million distribution from PennEast Pipeline. Three Months Ended March 31, Earnings from Equity Method Investments 2022 2021 (in millions) SNG $ 39 $ 38 Other (*) 1 3 Total $ 40 $ 41 (*) Earnings primarily result from AFUDC equity recorded by the project entity.

Financing

Financing	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Financing	FINANCING Bank Credit Arrangements See Note 8 to the financial statements under "Bank Credit Arrangements" in Item 8 of the Form 10-K for additional information. At March 31, 2022, committed credit arrangements with banks were as follows: Expires Company 2022 2024 2025 2026 Total Unused Expires within One Year (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 — 275 255 — Southern Power (a) — — — 600 600 568 — Southern Company Gas (b) 250 — — 1,500 1,750 1,747 250 SEGCO 30 — — — 30 30 30 Southern Company $ 280 $ 700 $ 125 $ 6,550 $ 7,655 $ 7,574 $ 280 (a) Does not include Southern Power Company's two $75 million continuing letter of credit facilities for standby letters of credit, expiring in 2023 and 2025, respectively, of which $11 million and $19 million, respectively, was unused at March 31, 2022. 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 arrangement expiring in 2026 and all $250 million of the arrangement expiring in 2022. 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. As reflected in the table above, in March 2022, Mississippi Power amended and restated its $125 million revolving credit arrangement, which among other things, extended the maturity date from 2023 to 2025 and allows for borrowing based on term SOFR. 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. At March 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. Earnings per Share For Southern Company, the only differences in computing basic and diluted earnings per share are attributable to awards outstanding under stock-based compensation plans and the equity units issued in 2019. Earnings per share dilution resulting from stock-based compensation plans and the equity units issuance is determined using the treasury stock method. See Note 8 to the financial statements under "Equity Units" in Item 8 of the Form 10-K for information on the equity units and Note 12 to the financial statements in Item 8 of the Form 10-K for information on stock-based compensation plans. Shares used to compute diluted earnings per share were as follows: Three Months Ended March 31, 2022 2021 (in millions) As reported shares 1,063 1,060 Effect of stock-based compensation 6 6 Diluted shares 1,069 1,066 An immaterial number of stock-based compensation awards was not included in the diluted earnings per share calculation because the awards were anti-dilutive for the three months ended March 31, 2022 and 2021.

Income Taxes

Income Taxes	3 Months Ended
	Mar. 31, 2022
Income Tax Disclosure [Abstract]
Income Taxes	INCOME TAXES See Note 10 to the financial statements in Item 8 of the Form 10-K for additional tax information. Current and Deferred Income Taxes Tax Credit and Net Operating Loss Carryforwards The utilization of each Registrant's estimated tax credit and state net operating loss carryforwards and related valuation allowances could be impacted by numerous factors, including the acquisition of additional renewable projects, an increase in Georgia Power's ownership interest percentage in Plant Vogtle Units 3 and 4, the purchase of rights to additional PTCs of Plant Vogtle Units 3 and 4 pursuant to certain joint ownership agreements, changes in taxable income projections, and potential income tax rate changes. See Note (B) and Note 2 to the financial statements in Item 8 of the Form 10-K under "Georgia Power – Nuclear Construction" for additional information on Plant Vogtle Units 3 and 4. 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. Details of significant changes in the effective tax rate for the applicable Registrants are provided herein. Mississippi Power Mississippi Power's effective tax rate was 16.4% for the three months ended March 31, 2022 compared to 8.4% for the corresponding period in 2021. The effective tax rate increase was primarily due to a decrease in the flowback of excess deferred income taxes beginning in April 2021. Southern Power Southern Power's effective tax benefit rate was (80.0)% for the three months ended March 31, 2022 compared to (17.3)% for the corresponding period in 2021. The effective tax rate decrease was primarily due to lower pre-tax earnings and higher wind PTCs in 2022, partially offset by changes in state apportionment methodology resulting from tax legislation enacted by the State of Alabama in February 2021.

Retirement Benefits

Retirement Benefits	3 Months Ended
	Mar. 31, 2022
Retirement Benefits [Abstract]
Retirement Benefits	RETIREMENT BENEFITS The Southern Company system has a qualified defined benefit, trusteed, pension plan covering substantially all employees, with the exception of employees at PowerSecure. The qualified pension plan is funded in accordance with requirements of the Employee Retirement Income Security Act of 1974, as amended (ERISA). No mandatory contributions to the qualified pension plan are anticipated for the year ending December 31, 2022. 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. During the first quarter 2022, the qualified pension plan achieved the predetermined funding threshold whereby the asset allocation was adjusted to invest a larger portion of the portfolio in fixed rate debt securities. See Note 11 to the financial statements in Item 8 of the Form 10-K for additional information. On each Registrant's condensed statements of income, the service cost component of net periodic benefit costs is included in other operations and maintenance expenses and all other components of net periodic benefit costs are included in other income (expense), net. Components of the net periodic benefit costs for the three months ended March 31, 2022 and 2021 are presented in the following tables. Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Three Months Ended March 31, 2022 Pension Plans Service cost $ 103 $ 25 $ 26 $ 4 $ 2 $ 9 Interest cost 102 24 31 5 2 7 Expected return on plan assets (316) (77) (99) (15) (4) (22) Amortization: Prior service costs — — — — — (1) Regulatory asset — — — — — 4 Net loss 60 16 18 3 1 2 Net periodic pension cost (income) $ (51) $ (12) $ (24) $ (3) $ 1 $ (1) Postretirement Benefits Service cost $ 6 $ 1 $ 2 $ — $ — $ — Interest cost 10 3 4 — — 1 Expected return on plan assets (20) (8) (7) — — (2) Amortization: Regulatory asset — — — — — 2 Net periodic postretirement benefit cost (income) $ (4) $ (4) $ (1) $ — $ — $ 1 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Three Months Ended March 31, 2021 Pension Plans Service cost $ 109 $ 26 $ 28 $ 4 $ 2 $ 9 Interest cost 87 20 26 4 1 6 Expected return on plan assets (298) (72) (94) (14) (3) (21) Amortization: Prior service costs — — — — — (1) Regulatory asset — — — — — 4 Net loss 78 21 25 4 1 3 Net periodic pension cost (income) $ (24) $ (5) $ (15) $ (2) $ 1 $ — Postretirement Benefits Service cost $ 6 $ 1 $ 2 $ — $ — $ — Interest cost 8 2 3 — — 1 Expected return on plan assets (19) (7) (7) — — (2) Amortization: Regulatory asset — — — — — 2 Net (gain)/loss 1 — 1 — — (1) Net periodic postretirement benefit cost (income) $ (4) $ (4) $ (1) $ — $ — $ —

Fair Value Measurements

Fair Value Measurements	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Fair Value Measurements	FAIR VALUE MEASUREMENTS At March 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: At March 31, 2022 Quoted Prices Significant Significant Net Asset Value as a Practical Expedient (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 74 $ 473 $ — $ — $ 547 Interest rate derivatives — 17 — — 17 Investments in trusts: (b)(c) Domestic equity 754 202 — — 956 Foreign equity 143 167 — — 310 U.S. Treasury and government agency securities — 290 — — 290 Municipal bonds — 53 — — 53 Pooled funds – fixed income — 10 — — 10 Corporate bonds 1 490 — — 491 Mortgage and asset backed securities — 88 — — 88 Private equity — — — 156 156 Cash and cash equivalents 3 — — — 3 Other 42 25 — — 67 Cash equivalents 1,182 17 — — 1,199 Other investments 9 32 — — 41 Total $ 2,208 $ 1,864 $ — $ 156 $ 4,228 Liabilities: Energy-related derivatives (a) $ 3 $ 7 $ — $ — $ 10 Interest rate derivatives — 139 — — 139 Foreign currency derivatives — 130 — — 130 Contingent consideration — — 14 — 14 Other — 13 — — 13 Total $ 3 $ 289 $ 14 $ — $ 306 Fair Value Measurements Using: At March 31, 2022 Quoted Prices Significant Significant Net Asset Value as a Practical Expedient (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 128 $ — $ — $ 128 Nuclear decommissioning trusts: (b) Domestic equity 452 193 — — 645 Foreign equity 143 — — — 143 U.S. Treasury and government agency securities — 21 — — 21 Municipal bonds — 2 — — 2 Corporate bonds 1 253 — — 254 Mortgage and asset backed securities — 20 — — 20 Private equity — — — 156 156 Other 14 — — — 14 Cash equivalents 1,129 17 — — 1,146 Other investments — 32 — — 32 Total $ 1,739 $ 666 $ — $ 156 $ 2,561 Liabilities: Energy-related derivatives $ — $ 2 $ — $ — $ 2 Georgia Power Assets: Energy-related derivatives $ — $ 179 $ — $ — $ 179 Interest rate derivatives — 12 — — 12 Nuclear decommissioning trusts: (b)(c) Domestic equity 302 1 — — 303 Foreign equity — 165 — — 165 U.S. Treasury and government agency securities — 269 — — 269 Municipal bonds — 51 — — 51 Corporate bonds — 237 — — 237 Mortgage and asset backed securities — 68 — — 68 Other 28 25 — — 53 Total $ 330 $ 1,007 $ — $ — $ 1,337 Liabilities: Energy-related derivatives $ — $ 1 $ — $ — $ 1 Fair Value Measurements Using: At March 31, 2022 Quoted Prices Significant Significant Net Asset Value as a Practical Expedient (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 138 $ — $ — $ 138 Liabilities: Energy-related derivatives $ — $ 2 $ — $ — $ 2 Southern Power Assets: Energy-related derivatives $ — $ 8 $ — $ — $ 8 Liabilities: Foreign currency derivatives $ — $ 43 $ — $ — $ 43 Contingent consideration — — 14 — 14 Other — 13 — — 13 Total $ — $ 56 $ 14 $ — $ 70 Southern Company Gas Assets: Energy-related derivatives (a) $ 74 $ 20 $ — $ — $ 94 Non-qualified deferred compensation trusts: Domestic equity — 8 — — 8 Foreign equity — 2 — — 2 Pooled funds – fixed income — 10 — — 10 Cash equivalents 3 — — — 3 Total $ 77 $ 40 $ — $ — $ 117 Liabilities: Energy-related derivatives (a) $ 3 $ 1 $ — $ — $ 4 Interest rate derivatives — 36 — — 36 Total $ 3 $ 37 $ — $ — $ 40 (a) Excludes cash collateral of $36 million. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 to the financial statements in Item 8 of the Form 10-K for additional information. (c) Includes investment securities pledged to creditors and collateral received and excludes payables related to the securities lending program. At March 31, 2022, approximately $72 million of the fair market value of Georgia Power's nuclear decommissioning trust funds' securities were on loan to creditors under the funds' managers' securities lending program. See Note 6 to the financial statements in Item 8 of the Form 10-K for additional information. Southern Company, Alabama Power, and Georgia Power continue to elect the option to fair value investment securities held in the nuclear decommissioning trust funds. The fair value of the funds, including reinvested interest and dividends and excluding the funds' expenses, increased (decreased) by the amounts shown in the table below for the three months ended March 31, 2022 and 2021. The changes were recorded as a change to the regulatory assets and liabilities related to AROs for Georgia Power and Alabama Power, respectively. Fair value increases (decreases) Three Months Ended March 31, 2022 Three Months Ended March 31, 2021 (in millions) Southern Company $ (150) $ 39 Alabama Power (67) 41 Georgia Power (83) (2) 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 (J) 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 to the financial statements under "Nuclear Decommissioning" in Item 8 of the Form 10-K 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. At March 31, 2022, 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 $156 million and unfunded commitments related to the private equity investments totaled $84 million. 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 March 31, 2022, other financial instruments for which the carrying amount did not equal fair value were as follows: Southern Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (*) (in billions) Long-term debt, including securities due within one year: Carrying amount $ 51.6 $ 9.8 $ 13.2 $ 1.5 $ 3.7 $ 6.9 Fair value 51.9 10.0 13.5 1.5 3.8 6.9 (*) 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	3 Months Ended
	Mar. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivatives	DERIVATIVESThe 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 (I) 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 to the financial statements under "Financial Instruments" in Item 8 of the Form 10-K for additional information. See Note 15 to the financial statements under "Southern Company Gas" in Item 8 of the Form 10-K 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 accumulated OCI 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 March 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 (*) 279 2030 2025 Alabama Power 65 2025 — Georgia Power 75 2024 — Mississippi Power 71 2026 — Southern Power 4 2030 — Southern Company Gas (*) 64 2024 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 66.2 million mmBtu and short natural gas positions of 2.6 million mmBtu at March 31, 2022, which is also included in Southern Company's total volume. 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 18 million mmBtu for Southern Company, which includes 4 million mmBtu for Alabama Power, 6 million mmBtu for Georgia Power, 3 million mmBtu for Mississippi Power, and 5 million mmBtu for Southern Power. For cash flow hedges of energy-related derivatives, the estimated pre-tax gains expected to be reclassified from accumulated OCI to earnings for the 12-month period ending March 31, 2023 are $29 million for Southern Company, $26 million for Southern Company Gas, and immaterial for all other Registrants. 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 March 31, 2022, the following interest rate derivatives were outstanding: Notional Interest Weighted Hedge Fair Value Gain (Loss) at March 31, 2022 (in millions) (in millions) Cash Flow Hedges of Forecasted Debt Georgia Power $ 200 1.87% — February 2032 $ 8 Georgia Power 100 2.27% — November 2051 4 Cash Flow Hedges of Existing Debt Southern Company parent 100 2.58% — April 2027 (1) Fair Value Hedges of Existing Debt Southern Company parent 400 1.75% 1-month LIBOR + 0.68% March 2028 (29) Southern Company parent 1,000 3.70% 1-month LIBOR + 2.36% April (69) Southern Company Gas 500 1.75% 1-month LIBOR + 0.38% January 2031 (35) Southern Company $ 2,300 $ (122) For cash flow hedge interest rate derivatives, the estimated pre-tax gains (losses) expected to be reclassified from accumulated OCI to interest expense for the 12-month period ending March 31, 2023 total $(20) million for Southern Company and are immaterial for all other Registrants. Deferred gains and losses related to interest rate derivatives are expected to be amortized into earnings through 2051 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 March 31, 2022, the following foreign currency derivatives were outstanding: Pay Notional Pay Receive Notional Receive Hedge Fair Value Gain (Loss) at March 31, 2022 (in millions) (in millions) (in millions) Fair Value Hedges of Existing Debt Southern Company parent $ 1,476 3.39% € 1,250 1.88% September 2027 $ (87) Cash Flow Hedges of Existing Debt Southern Power $ 677 2.95% € 600 1.00% June 2022 $ (24) Southern Power 564 3.78% 500 1.85% June 2026 (19) Southern Power total $ 1,241 € 1,100 $ (43) Southern Company $ 2,717 € 2,350 $ (130) The estimated pre-tax losses related to Southern Power's foreign currency derivatives accounted for as cash flow hedges expected to be reclassified from accumulated OCI to earnings for the 12-month period ending March 31, 2023 are $17 million. 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. The fair value of energy-related derivatives, interest rate derivatives, and foreign currency derivatives was reflected in the balance sheets as follows: At March 31, 2022 At December 31, 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) (in millions) Southern Company Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 381 $ 1 $ 129 $ 30 Other deferred charges and assets/Other deferred credits and liabilities 116 6 72 6 Total derivatives designated as hedging instruments for regulatory purposes $ 497 $ 7 $ 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 $ 28 $ 2 $ 7 $ 5 Other deferred charges and assets/Other deferred credits and liabilities 5 — 1 — Interest rate derivatives: Assets from risk management activities/Other current liabilities 17 3 19 — Other deferred charges and assets/Other deferred credits and liabilities — 136 — 29 Foreign currency derivatives: Assets from risk management activities/Other current liabilities — 59 — 39 Other deferred charges and assets/Other deferred credits and liabilities — 71 — 40 Total derivatives designated as hedging instruments in cash flow and fair value hedges $ 50 $ 271 $ 27 $ 113 Derivatives not designated as hedging instruments Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 16 $ 2 $ 9 $ 4 Other deferred charges and assets/Other deferred credits and liabilities 1 — 1 — Total derivatives not designated as hedging instruments $ 17 $ 2 $ 10 $ 4 Gross amounts recognized $ 564 $ 280 $ 238 $ 153 Gross amounts offset (a) (45) (9) (25) (28) Net amounts recognized in the Balance Sheets (b) $ 519 $ 271 $ 213 $ 125 At March 31, 2022 At December 31, 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) (in millions) Alabama Power Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Other current assets/Other current liabilities $ 87 $ — $ 30 $ 9 Other deferred charges and assets/Other deferred credits and liabilities 41 2 25 2 Total derivatives designated as hedging instruments for regulatory purposes $ 128 $ 2 $ 55 $ 11 Gross amounts offset (2) (2) (5) (5) Net amounts recognized in the Balance Sheets $ 126 $ — $ 50 $ 6 Georgia Power Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 150 $ — $ 54 $ 6 Other deferred charges and assets/Other deferred credits and liabilities 29 1 21 2 Total derivatives designated as hedging instruments for regulatory purposes $ 179 $ 1 $ 75 $ 8 Derivatives designated as hedging instruments in cash flow and fair value hedges Interest rate derivatives: Assets from risk management activities/Other current liabilities $ 12 $ — $ — $ — Total derivatives designated as hedging instruments in cash flow and fair value hedges $ 12 $ — $ — $ — Gross amounts recognized $ 191 $ 1 $ 75 $ 8 Gross amounts offset (1) (1) (8) (8) Net amounts recognized in the Balance Sheets $ 190 $ — $ 67 $ — Mississippi Power Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 94 $ — $ 30 $ 3 Other deferred charges and assets/Other deferred credits and liabilities 44 2 26 2 Total derivatives designated as hedging instruments for regulatory purposes $ 138 $ 2 $ 56 $ 5 Gross amounts offset (2) (2) (4) (4) Net amounts recognized in the Balance Sheets $ 136 $ — $ 52 $ 1 At March 31, 2022 At December 31, 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) (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 $ 3 $ — $ 2 $ — Other deferred charges and assets/Other deferred credits and liabilities 3 — 1 — Foreign currency derivatives: Other current assets/Other current liabilities — 35 — 16 Other deferred charges and assets/Other deferred credits and liabilities — 8 — — Total derivatives designated as hedging instruments in cash flow and fair value hedges $ 6 $ 43 $ 3 $ 16 Derivatives not designated as hedging instruments Energy-related derivatives: Other current assets/Other current liabilities $ 2 $ — $ 1 $ — Gross amounts recognized $ 8 $ 43 $ 4 $ 16 Gross amounts offset — — — — Net amounts recognized in the Balance Sheets $ 8 $ 43 $ 4 $ 16 At March 31, 2022 At December 31, 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) (in millions) Southern Company Gas Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 49 $ 1 $ 15 $ 12 Other deferred charges and assets/Other deferred credits and liabilities 3 — — — Total derivatives designated as hedging instruments for regulatory purposes $ 52 $ 1 $ 15 $ 12 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 25 $ 2 $ 5 $ 5 Other deferred charges and assets/Other deferred credits and liabilities 2 — — — Interest rate derivatives: Assets from risk management activities/Liabilities from risk management activities-current — — 6 — Other deferred charges and assets/Other deferred credits and liabilities — 36 — 6 Total derivatives designated as hedging instruments in cash flow and fair value hedges $ 27 $ 38 $ 11 $ 11 Derivatives not designated as hedging instruments Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 14 $ 1 $ 8 $ 4 Other deferred charges and assets/Other deferred credits and liabilities 1 — 1 — Total derivatives not designated as hedging instruments $ 15 $ 1 $ 9 $ 4 Gross amounts recognized $ 94 $ 40 $ 35 $ 27 Gross amounts offset (a) (40) (4) (8) (11) Net amounts recognized in the Balance Sheets (b) $ 54 $ 36 $ 27 $ 16 (a) Gross amounts offset include cash collateral held on deposit in broker margin accounts of $36 million and $3 million at March 31, 2022 and December 31, 2021, respectively. (b) Net amounts of derivative instruments outstanding exclude immaterial premium and intrinsic value associated with weather derivatives for both periods presented. Energy-related derivatives not designated as hedging instruments were immaterial for the traditional electric operating companies at March 31, 2022. There were no such instruments for the traditional electric operating companies at December 31, 2021. At March 31, 2022 and December 31, 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 Sheet Derivative Category and Balance Sheet Southern Alabama Georgia Mississippi Southern Company Gas (in millions) At March 31, 2022: Energy-related derivatives: Other regulatory liabilities, current $ 353 $ 87 $ 150 $ 94 $ 22 Other regulatory liabilities, deferred 111 39 28 42 2 Total energy-related derivative gains (losses) $ 464 $ 126 $ 178 $ 136 $ 24 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 three months ended March 31, 2022 and 2021, the pre-tax effects of cash flow and fair value hedge accounting on accumulated OCI were as follows: Gain (Loss) Recognized in OCI on Derivative For the Three Months Ended March 31, 2022 2021 (in millions) Southern Company Cash flow hedges: Energy-related derivatives $ 42 $ 5 Interest rate derivatives 9 3 Foreign currency derivatives (28) (47) Fair value hedges (*) : Foreign currency derivatives 4 — Total $ 27 $ (39) Georgia Power Cash flow hedges: Interest rate derivatives $ 12 $ — Southern Power Cash flow hedges: Energy-related derivatives $ 5 $ 4 Foreign currency derivatives (28) (47) Total $ (23) $ (43) Southern Company Gas Cash flow hedges: Energy-related derivatives $ 37 $ 1 (*) Represents amounts excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI. For the three months ended March 31, 2022 and 2021, the pre-tax effects of interest rate derivatives designated as cash flow hedging instruments on accumulated OCI were immaterial for the other Registrants. For the three months ended March 31, 2022 and 2021, the pre-tax effects of cash flow and fair value hedge accounting on income were as follows: Location and Amount of Gain (Loss) Recognized in Income on Cash Flow and Fair Value Hedging Relationships For the Three Months Ended March 31, 2022 2021 (in millions) Southern Company Total cost of natural gas $ 1,095 $ 583 Gain (loss) on energy-related cash flow hedges (a) 9 (3) Total depreciation and amortization 892 871 Gain (loss) on energy-related cash flow hedges (a) 2 3 Total interest expense, net of amounts capitalized (462) (450) Gain (loss) on interest rate cash flow hedges (a) (7) (7) Gain (loss) on foreign currency cash flow hedges (a) (6) (6) Gain (loss) on interest rate fair value hedges (b) (123) (10) Total other income (expense), net 145 58 Gain (loss) on foreign currency cash flow hedges (a)(c) (25) (60) Gain (loss) on foreign currency fair value hedges (24) — Amount excluded from effectiveness testing recognized in earnings (4) — Southern Power Total depreciation and amortization $ 120 $ 119 Gain (loss) on energy-related cash flow hedges (a) 2 3 Total interest expense, net of amounts capitalized (37) (38) Gain (loss) on foreign currency cash flow hedges (a) (6) (6) Total other income (expense), net 2 7 Gain (loss) on foreign currency cash flow hedges (a)(c) (25) (60) Southern Company Gas Total cost of natural gas $ 1,095 $ 583 Gain (loss) on energy-related cash flow hedges (a) 9 — Total interest expense, net of amounts capitalized (61) (60) Gain (loss) on interest rate cash flow hedges (a) (1) — Gain (loss) on interest rate fair value hedges (b) (36) — (a) Reclassified from accumulated OCI 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 accumulated OCI 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. For the three months ended March 31, 2022 and 2021, the pre-tax effects of cash flow and fair value hedge accounting on income for energy-related derivatives and interest rate derivatives were immaterial for the traditional electric operating companies. At March 31, 2022 and December 31, 2021, the following amounts were recorded on the balance sheets related to cumulative basis adjustments for fair value hedges: Carrying Amount of the Hedged Item Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item Balance Sheet Location of Hedged Items At March 31, 2022 At December 31, 2021 At March 31, 2022 At December 31, 2021 (in millions) (in millions) Southern Company Long-term debt $ (3,136) $ (3,280) $ 126 $ 9 Southern Company Gas Long-term debt $ (459) $ (493) $ 37 $ 2 For the three months ended March 31, 2022 and 2021, 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 were as follows: Gain (Loss) Three Months Ended March 31, Derivatives in Non-Designated Hedging Relationships Statements of Income Location 2022 2021 (in millions) Energy-related derivatives: Natural gas revenues (*) $ 2 $ (17) Cost of natural gas 21 7 Total derivatives in non-designated hedging relationships $ 23 $ (10) (*) Excludes immaterial gains (losses) recorded in natural gas revenues associated with weather derivatives for all periods presented. For the three months ended March 31, 2022 and 2021, the pre-tax effects of interest rate derivatives not designated as hedging instruments were immaterial for Southern Company and Southern Company Gas and the pre-tax effects of energy-related derivatives not designated as hedging instruments were immaterial for all other Registrants. 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. At March 31, 2022, the Registrants had no collateral posted with derivative counterparties to satisfy these arrangements. For the applicable Registrants, the fair value of interest rate and 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 at March 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. Following the sale of Gulf Power to NextEra Energy, Inc., Gulf Power has continued participating in the Southern Company power pool; however, the parties currently expect this participation to end during the third quarter 2022. Generally, collateral may be provided by a Southern Company guaranty, letter of credit, or cash. If collateral is required, fair value amounts recognized for the right to reclaim cash collateral or the obligation to return cash collateral are not offset against fair value amounts recognized for derivatives executed with the same counterparty. 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 March 31, 2022, cash collateral posted in these accounts was immaterial. 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 March 31, 2022, cash collateral held on deposit in broker margin accounts was $36 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	3 Months Ended
	Mar. 31, 2022
Business Combination and Asset Acquisition [Abstract]
Acquisitions and Dispositions	ACQUISITIONS AND DISPOSITIONSSee Note 15 to the financial statements in Item 8 of the Form 10-K for additional information. Southern Power Construction Projects During the three months ended March 31, 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. Project Facility Resource Approximate Nameplate Capacity ( MW ) Location COD PPA Contract Period Projects Completed During the Three Months Ended March 31, 2022 Garland Solar Storage (a) Battery energy storage system 88 Kern County, CA September 2021 through February 2022 (b) 20 years Tranquillity Solar Storage (a) Battery energy storage system 72 Fresno County, CA November 2021 through March 2022 (c) 20 years (a) 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.

Segment and Related Information

Segment and Related Information	3 Months Ended
	Mar. 31, 2022
Segment Reporting [Abstract]
Segment and Related Information	SEGMENT AND RELATED INFORMATION Southern Company The primary businesses of the Southern Company system are electricity sales by the traditional electric operating companies and Southern Power and the distribution of natural gas by Southern Company Gas. The traditional electric operating companies 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 and battery energy storage projects, and sells electricity at market-based rates in the wholesale market. Southern Company Gas distributes natural gas through its natural gas distribution utilities and is involved in several other complementary businesses including gas pipeline investments and gas marketing services. Prior to the sale of Sequent on July 1, 2021, Southern Company Gas' other businesses also included wholesale gas services. 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 $105 million and $81 million for the three months ended March 31, 2022 and 2021, respectively. Revenues from sales of natural gas from Southern Company Gas to the traditional electric operating companies were immaterial for both periods presented. Revenues from sales of natural gas from Southern Company Gas to Southern Power were $12 million for the three months ended March 31, 2021, which represented sales from Sequent prior to its sale. 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, for the three months ended March 31, 2021, leveraged lease projects. All other inter-segment revenues are not material. Financial data for business segments and products and services for the three months ended March 31, 2022 and 2021 was as follows: Electric Utilities Traditional Southern Eliminations Total Southern Company Gas All Eliminations Consolidated (in millions) Three Months Ended March 31, 2022 Operating revenues $ 4,191 $ 539 $ (221) $ 4,509 $ 2,058 $ 123 $ (42) $ 6,648 Segment net income (loss) (a) 774 72 — 846 319 (125) (8) 1,032 At March 31, 2022 Goodwill $ — $ 2 $ — $ 2 $ 5,015 $ 263 $ — $ 5,280 Total assets 90,460 13,766 (627) 103,599 23,377 4,236 (2,573) 128,639 Three Months Ended March 31, 2021 Operating revenues $ 3,764 $ 440 $ (87) $ 4,117 $ 1,694 $ 134 $ (35) $ 5,910 Segment net income (loss) (a)(b)(c) 756 97 — 853 398 (108) (8) 1,135 At December 31, 2021 Goodwill $ — $ 2 $ — $ 2 $ 5,015 $ 263 $ — $ 5,280 Total assets 89,051 13,390 (667) 101,774 23,560 2,975 (775) 127,534 (a) Attributable to Southern Company. (b) For the traditional electric operating companies, includes a pre-tax charge of $48 million ($36 million after tax) at Georgia Power for estimated losses associated with the construction of Plant Vogtle Units 3 and 4. See Note (B) and Note 2 to the financial statements in Item 8 of the Form 10-K under "Georgia Power – Nuclear Construction" for additional information. (c) 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 Note 15 to the financial statements under "Southern Power – Development Projects" in Item 8 of the Form 10-K for additional information. Products and Services Electric Utilities' Revenues Retail Wholesale Other Total (in millions) Three Months Ended March 31, 2022 $ 3,613 $ 664 $ 232 $ 4,509 Three Months Ended March 31, 2021 3,342 545 230 4,117 Southern Company Gas' Revenues Gas Wholesale Gas Services (*) Gas Other Total (in millions) Three Months Ended March 31, 2022 $ 1,791 $ — $ 243 $ 24 $ 2,058 Three Months Ended March 31, 2021 1,192 298 195 9 1,694 (*) Prior to the sale of Sequent, the revenues for wholesale gas services were netted with costs associated with its energy and risk management activities. See "Southern Company Gas" herein and Note 15 to the financial statements under "Southern Company Gas" in Item 8 of the Form 10-K for additional information. 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 to the financial statements under "Southern Company Gas" in Item 8 of the Form 10-K for additional information on the sale of Sequent. 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. See Note 7 to the financial statements under "Southern Company Gas" in Item 8 of the Form 10-K 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. Business segment financial data for the three months ended March 31, 2022 and 2021 was as follows: Gas Distribution Operations Gas Pipeline Investments Wholesale Gas Services (*) Gas Marketing Services Total All Other Eliminations Consolidated (in millions) Three Months Ended March 31, 2022 Operating revenues $ 1,803 $ 8 $ — $ 243 $ 2,054 $ 16 $ (12) $ 2,058 Segment net income (loss) 214 29 — 66 309 10 — 319 Total assets at March 31, 2022 21,034 1,473 — 1,640 24,147 12,017 (12,787) 23,377 Three Months Ended March 31, 2021 Operating revenues $ 1,200 $ 8 $ 298 $ 195 $ 1,701 $ 7 $ (14) $ 1,694 Segment net income (loss) 183 29 126 56 394 4 — 398 Total assets at December 31, 2021 20,917 1,467 31 1,556 23,971 12,114 (12,525) 23,560 (*) As a result of the sale of Sequent, wholesale gas services is no longer a reportable segment for the three months ended March 31, 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) Three Months Ended March 31, 2021 $ 2,588 $ 63 $ 2,651 $ 2,353 $ 298

Introduction (Policies)

Introduction (Policies)	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Accounting	The condensed quarterly financial statements of each Registrant included herein have been prepared by such Registrant, without audit, pursuant to the rules and regulations of the SEC. The Condensed Balance Sheets at December 31, 2021 have been derived from the audited financial statements of each Registrant. In the opinion of each Registrant's management, the information regarding such Registrant furnished herein reflects all adjustments, which, except as otherwise disclosed, are of a normal recurring nature, necessary to present fairly the results of operations for the periods ended March 31, 2022 and 2021. Certain information and footnote disclosures normally included in annual financial statements prepared in accordance with GAAP have been condensed or omitted pursuant to such rules and regulations, although each Registrant believes that the disclosures regarding such Registrant are adequate to make the information presented not misleading. Disclosures which would substantially duplicate the disclosures in the Form 10-K and details which have not changed significantly in amount or composition since the filing of the Form 10-K are generally omitted from this Quarterly Report on Form 10-Q unless specifically required by GAAP. Therefore, these Condensed Financial Statements should be read in conjunction with the financial statements and the notes thereto included in the Form 10-K. Due to the seasonal variations in the demand for energy and other factors, operating results for the periods presented are not necessarily indicative of the operating results to be expected for the full year.
Reclassifications	Certain prior year data presented in the financial statements have been reclassified to conform to the current year presentation. These reclassifications had no impact on the overall results of operations, financial position, or cash flows of any Registrant.
Goodwill	Goodwill is not amortized, but is subject to an annual impairment test during the fourth quarter of each year, or more frequently if impairment indicators arise.
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. For any declines in market prices below the WACOG considered to be other than temporary, an adjustment is recorded to reduce the value of natural gas inventories to market value. 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.
Valuation Methodologies	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 (J) 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 to the financial statements under "Nuclear Decommissioning" in Item 8 of the Form 10-K for additional information.
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 (I) 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 to the financial statements under "Financial Instruments" in Item 8 of the Form 10-K for additional information. See Note 15 to the financial statements under "Southern Company Gas" in Item 8 of the Form 10-K 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 accumulated OCI 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.

Introduction (Tables)

Introduction (Tables)	3 Months Ended
	Mar. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Goodwill	Goodwill at March 31, 2022 and December 31, 2021 was as follows: Goodwill (in millions) Southern Company $ 5,280 Southern Company Gas: Gas distribution operations $ 4,034 Gas marketing services 981 Southern Company Gas total $ 5,015
Schedule of Other Intangible Assets, Indefinite-Lived	Other intangible assets were as follows: At March 31, 2022 At December 31, 2021 Gross Carrying Amount Accumulated Amortization Other Gross Carrying Amount Accumulated Amortization Other (in millions) (in millions) Southern Company Other intangible assets subject to amortization: Customer relationships $ 212 $ (152) $ 60 $ 212 $ (150) $ 62 Trade names 64 (41) 23 64 (38) 26 PPA fair value adjustments 390 (114) 276 390 (109) 281 Other 11 (10) 1 11 (10) 1 Total other intangible assets subject to amortization $ 677 $ (317) $ 360 $ 677 $ (307) $ 370 Other intangible assets not subject to amortization: Federal Communications Commission licenses 75 — 75 75 — 75 Total other intangible assets $ 752 $ (317) $ 435 $ 752 $ (307) $ 445 Southern Power Other intangible assets subject to amortization: PPA fair value adjustments $ 390 $ (114) $ 276 $ 390 $ (109) $ 281 Southern Company Gas Other intangible assets subject to amortization: Gas marketing services Customer relationships $ 156 $ (132) $ 24 $ 156 $ (130) $ 26 Trade names 26 (16) 10 26 (15) 11 Total other intangible assets subject to amortization $ 182 $ (148) $ 34 $ 182 $ (145) $ 37
Schedule of Other Intangible Assets, Finite-Lived	Other intangible assets were as follows: At March 31, 2022 At December 31, 2021 Gross Carrying Amount Accumulated Amortization Other Gross Carrying Amount Accumulated Amortization Other (in millions) (in millions) Southern Company Other intangible assets subject to amortization: Customer relationships $ 212 $ (152) $ 60 $ 212 $ (150) $ 62 Trade names 64 (41) 23 64 (38) 26 PPA fair value adjustments 390 (114) 276 390 (109) 281 Other 11 (10) 1 11 (10) 1 Total other intangible assets subject to amortization $ 677 $ (317) $ 360 $ 677 $ (307) $ 370 Other intangible assets not subject to amortization: Federal Communications Commission licenses 75 — 75 75 — 75 Total other intangible assets $ 752 $ (317) $ 435 $ 752 $ (307) $ 445 Southern Power Other intangible assets subject to amortization: PPA fair value adjustments $ 390 $ (114) $ 276 $ 390 $ (109) $ 281 Southern Company Gas Other intangible assets subject to amortization: Gas marketing services Customer relationships $ 156 $ (132) $ 24 $ 156 $ (130) $ 26 Trade names 26 (16) 10 26 (15) 11 Total other intangible assets subject to amortization $ 182 $ (148) $ 34 $ 182 $ (145) $ 37
Schedule of Amortization of Other Intangible Assets	Amortization associated with other intangible assets was as follows: Three Months Ended March 31, 2022 (in millions) Southern Company (a) $ 10 Southern Power (b) 5 Southern Company Gas 3 (a) Includes $5 million recorded as a reduction to operating revenues. (b) Recorded as a reduction to operating revenues.
Schedule of Restrictions on Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed balance sheets that total to the amount shown in the condensed statements of cash flows for the applicable Registrants: Southern Southern Southern March 31, 2022 December 31, 2021 March 31, 2022 December 31, 2021 March 31, 2022 December 31, 2021 (in millions) Cash and cash equivalents $ 1,662 $ 1,798 $ 130 $ 107 $ 31 $ 45 Restricted cash (a) : Other current assets 2 2 — — 2 2 Other deferred charges and assets 9 29 9 29 — — Total cash, cash equivalents, and restricted cash (b) $ 1,673 $ 1,829 $ 139 $ 135 $ 33 $ 48 (a) For Southern Power, restricted cash reflects $9 million and $10 million at March 31, 2022 and December 31, 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. For Southern Company Gas, reflects restricted cash held as collateral for workers' compensation, life insurance, and long-term disability insurance. (b) Total may not add due to rounding.
Schedule of Cash and Cash Equivalents	The following table provides a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed balance sheets that total to the amount shown in the condensed statements of cash flows for the applicable Registrants: Southern Southern Southern March 31, 2022 December 31, 2021 March 31, 2022 December 31, 2021 March 31, 2022 December 31, 2021 (in millions) Cash and cash equivalents $ 1,662 $ 1,798 $ 130 $ 107 $ 31 $ 45 Restricted cash (a) : Other current assets 2 2 — — 2 2 Other deferred charges and assets 9 29 9 29 — — Total cash, cash equivalents, and restricted cash (b) $ 1,673 $ 1,829 $ 139 $ 135 $ 33 $ 48 (a) For Southern Power, restricted cash reflects $9 million and $10 million at March 31, 2022 and December 31, 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. For Southern Company Gas, reflects restricted cash held as collateral for workers' compensation, life insurance, and long-term disability insurance. (b) Total may not add due to rounding.

Regulatory Matters (Tables)

Regulatory Matters (Tables)	3 Months Ended
	Mar. 31, 2022
Regulated Operations [Abstract]
Schedule of Cost Recovery Clauses	The recovery balances for certain retail regulatory clauses of the traditional electric operating companies and Southern Company Gas at March 31, 2022 and December 31, 2021 were as follows: Regulatory Clause Balance Sheet Line Item March 31, December 31, 2021 (in millions) Alabama Power Rate CNP Compliance Other regulatory assets, deferred $ 12 $ 16 Rate CNP PPA Other regulatory assets, deferred 84 84 Retail Energy Cost Recovery (*) Other regulatory assets, deferred 46 126 Georgia Power Fuel Cost Recovery Deferred under recovered fuel clause revenues $ 494 $ 410 Mississippi Power Fuel Cost Recovery Other customer accounts receivable $ 16 $ 4 Ad Valorem Tax Other regulatory assets, current 12 12 Other regulatory assets, deferred 33 37 Southern Company Gas Natural Gas Cost Recovery Natural gas cost under recovery $ 306 $ 266 Other regulatory assets, deferred 44 207 Other regulatory liabilities, current 13 — (*) 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.
Nuclear Construction 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 first quarter 2023 and the fourth quarter 2023, respectively, is as follows: (in millions) Base project capital cost forecast (a)(b) $ 10,294 Construction contingency estimate 107 Total project capital cost forecast (a)(b) 10,401 Net investment at March 31, 2022 (b) (8,715) Remaining estimate to complete $ 1,686 (a) Includes approximately $590 million of costs that are not shared with the other Vogtle Owners and approximately $440 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 $377 million, of which $221 million had been accrued through March 31, 2022. (b) Net of $1.7 billion received from Toshiba under the Guarantee Settlement Agreement and approximately $188 million in related customer refunds.
Schedule of Infrastructure Replacement Programs and Capital Projects	Capital expenditures incurred under specific infrastructure replacement programs and capital projects during the first three months of 2022 were as follows: Utility Program Three Months Ended March 31, 2022 (in millions) Nicor Gas Investing in Illinois $ 51 Virginia Natural Gas Steps to Advance Virginia's Energy 14 Atlanta Gas Light System Reinforcement Rider 14 Chattanooga Gas Pipeline Replacement Program 1 Total $ 80

Revenue from Contracts with C_2

Revenue from Contracts with Customers and Lease Income (Tables)	3 Months Ended
	Mar. 31, 2022
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregation of Revenue	The following table disaggregates revenue from contracts with customers for the three months ended March 31, 2022 and 2021: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Three Months Ended March 31, 2022 Operating revenues Retail electric revenues Residential $ 1,525 $ 634 $ 821 $ 70 $ — $ — Commercial 1,178 375 738 65 — — Industrial 727 323 334 70 — — Other 26 4 20 2 — — Total retail electric revenues 3,456 1,336 1,913 207 — — Natural gas distribution revenues Residential 1,016 — — — — 1,016 Commercial 270 — — — — 270 Transportation 337 — — — — 337 Industrial 32 — — — — 32 Other 129 — — — — 129 Total natural gas distribution revenues 1,784 — — — — 1,784 Wholesale electric revenues PPA energy revenues 342 59 32 3 251 — PPA capacity revenues 134 39 12 3 81 — Non-PPA revenues 58 64 9 102 73 — Total wholesale electric revenues 534 162 53 108 405 — Other natural gas revenues Gas marketing services 243 — — — — 243 Other natural gas revenues 16 — — — — 16 Total natural gas revenues 259 — — — — 259 Other revenues 225 48 95 9 8 — Total revenue from contracts with customers 6,258 1,546 2,061 324 413 2,043 Other revenue sources (a) 390 103 147 11 126 15 Total operating revenues $ 6,648 $ 1,649 $ 2,208 $ 335 $ 539 $ 2,058 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Three Months Ended March 31, 2021 Operating revenues Retail electric revenues Residential $ 1,468 $ 628 $ 776 $ 64 $ — $ — Commercial 1,117 372 686 59 — — Industrial 668 320 284 64 — — Other 24 5 17 2 — — Total retail electric revenues 3,277 1,325 1,763 189 — — Natural gas distribution revenues Residential 614 — — — — 614 Commercial 170 — — — — 170 Transportation 288 — — — — 288 Industrial 16 — — — — 16 Other 97 — — — — 97 Total natural gas distribution revenues 1,185 — — — — 1,185 Wholesale electric revenues PPA energy revenues 212 43 13 4 156 — PPA capacity revenues 119 29 13 3 75 — Non-PPA revenues 67 32 9 88 61 — Total wholesale electric revenues 398 104 35 95 292 — Other natural gas revenues Wholesale gas services 1,590 — — — — 1,590 Gas marketing services 194 — — — — 194 Other natural gas revenues 7 — — — — 7 Total natural gas revenues 1,791 — — — — 1,791 Other revenues 249 46 113 8 4 — Total revenue from contracts with customers 6,900 1,475 1,911 292 296 2,976 Other revenue sources (a) 1,306 84 59 15 144 1,014 Other adjustments (b) (2,296) — — — — (2,296) Total operating revenues $ 5,910 $ 1,559 $ 1,970 $ 307 $ 440 $ 1,694 (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 Note 15 to the financial statements under "Southern Company Gas" in Item 8 of the Form 10-K and Note (L) under "Southern Company Gas" for information on the sale of Sequent and components of wholesale gas services' operating revenues, respectively.
Schedule of Contract Balances	The following table reflects the closing balances of receivables, contract assets, and contract liabilities related to revenues from contracts with customers at March 31, 2022 and December 31, 2021: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Accounts Receivable At March 31, 2022 $ 2,571 $ 616 $ 695 $ 85 $ 128 $ 865 At December 31, 2021 2,504 589 736 73 149 753 Contract Assets At March 31, 2022 $ 81 $ 2 $ 31 $ — $ — $ — At December 31, 2021 117 2 63 — 1 — Contract Liabilities At March 31, 2022 $ 72 $ 3 $ 13 $ 2 $ 1 $ — At December 31, 2021 57 4 14 — 1 —
Schedule of Remaining Performance Obligations	Revenues from contracts with customers related to these performance obligations remaining at March 31, 2022 are expected to be recognized as follows: 2022 (remaining) 2023 2024 2025 2026 Thereafter (in millions) Southern Company $ 529 $ 459 $ 351 $ 321 $ 307 $ 2,345 Alabama Power 24 24 7 5 — — Georgia Power 55 55 26 22 11 21 Southern Power 252 294 310 294 299 2,339
Schedule of Lease Income	Lease income for the three months ended March 31, 2022 and 2021 is as follows: Southern Alabama Power Georgia Power Mississippi Southern Power Southern Company Gas (in millions) For the Three Months Ended March 31, 2022 Lease income - interest income on sales-type leases $ 6 $ — $ — $ 4 $ 2 $ — Lease income - operating leases 51 20 8 — 21 9 Variable lease income 84 — — — 90 — Total lease income $ 141 $ 20 $ 8 $ 4 $ 113 $ 9 For the Three Months Ended March 31, 2021 Lease income - interest income on sales-type leases $ 3 $ — $ — $ 3 $ — $ — Lease income - operating leases 55 21 10 — 21 9 Variable lease income 84 — — — 90 — Total lease income $ 142 $ 21 $ 10 $ 3 $ 111 $ 9

Consolidated Entities and Equ_2

Consolidated Entities and Equity Method Investments (Tables)	3 Months Ended
	Mar. 31, 2022
Regulated Operations [Abstract]
Schedule of Equity Method Investments	The carrying amounts of Southern Company Gas' equity method investments at March 31, 2022 and December 31, 2021 and related earnings from those investments for the three months ended March 31, 2022 and 2021 were as follows: Investment Balance March 31, 2022 December 31, 2021 (in millions) SNG $ 1,138 $ 1,129 Other (*) 40 44 Total $ 1,178 $ 1,173 (*) Balance at March 31, 2022 reflects a $4 million distribution from PennEast Pipeline.
Schedule of Earnings (Loss) from Equity Method Investments	Three Months Ended March 31, Earnings from Equity Method Investments 2022 2021 (in millions) SNG $ 39 $ 38 Other (*) 1 3 Total $ 40 $ 41 (*) Earnings primarily result from AFUDC equity recorded by the project entity.

Financing (Tables)

Financing (Tables)	3 Months Ended
	Mar. 31, 2022
Debt Disclosure [Abstract]
Schedule of Credit Arrangements	At March 31, 2022, committed credit arrangements with banks were as follows: Expires Company 2022 2024 2025 2026 Total Unused Expires within One Year (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 — 275 255 — Southern Power (a) — — — 600 600 568 — Southern Company Gas (b) 250 — — 1,500 1,750 1,747 250 SEGCO 30 — — — 30 30 30 Southern Company $ 280 $ 700 $ 125 $ 6,550 $ 7,655 $ 7,574 $ 280 (a) Does not include Southern Power Company's two $75 million continuing letter of credit facilities for standby letters of credit, expiring in 2023 and 2025, respectively, of which $11 million and $19 million, respectively, was unused at March 31, 2022. 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 arrangement expiring in 2026 and all $250 million of the arrangement expiring in 2022. 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.
Schedule of Shares Used to Compute Diluted Earnings Per Share	Shares used to compute diluted earnings per share were as follows: Three Months Ended March 31, 2022 2021 (in millions) As reported shares 1,063 1,060 Effect of stock-based compensation 6 6 Diluted shares 1,069 1,066

Retirement Benefits (Tables)

Retirement Benefits (Tables)	3 Months Ended
	Mar. 31, 2022
Retirement Benefits [Abstract]
Schedule of Pension Plans and Postretirement Plans	Components of the net periodic benefit costs for the three months ended March 31, 2022 and 2021 are presented in the following tables. Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Three Months Ended March 31, 2022 Pension Plans Service cost $ 103 $ 25 $ 26 $ 4 $ 2 $ 9 Interest cost 102 24 31 5 2 7 Expected return on plan assets (316) (77) (99) (15) (4) (22) Amortization: Prior service costs — — — — — (1) Regulatory asset — — — — — 4 Net loss 60 16 18 3 1 2 Net periodic pension cost (income) $ (51) $ (12) $ (24) $ (3) $ 1 $ (1) Postretirement Benefits Service cost $ 6 $ 1 $ 2 $ — $ — $ — Interest cost 10 3 4 — — 1 Expected return on plan assets (20) (8) (7) — — (2) Amortization: Regulatory asset — — — — — 2 Net periodic postretirement benefit cost (income) $ (4) $ (4) $ (1) $ — $ — $ 1 Southern Alabama Georgia Mississippi Southern Power Southern Company Gas (in millions) Three Months Ended March 31, 2021 Pension Plans Service cost $ 109 $ 26 $ 28 $ 4 $ 2 $ 9 Interest cost 87 20 26 4 1 6 Expected return on plan assets (298) (72) (94) (14) (3) (21) Amortization: Prior service costs — — — — — (1) Regulatory asset — — — — — 4 Net loss 78 21 25 4 1 3 Net periodic pension cost (income) $ (24) $ (5) $ (15) $ (2) $ 1 $ — Postretirement Benefits Service cost $ 6 $ 1 $ 2 $ — $ — $ — Interest cost 8 2 3 — — 1 Expected return on plan assets (19) (7) (7) — — (2) Amortization: Regulatory asset — — — — — 2 Net (gain)/loss 1 — 1 — — (1) Net periodic postretirement benefit cost (income) $ (4) $ (4) $ (1) $ — $ — $ —

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	3 Months Ended
	Mar. 31, 2022
Fair Value Disclosures [Abstract]
Schedule of Assets and Liabilities Measured at Fair Value	At March 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: At March 31, 2022 Quoted Prices Significant Significant Net Asset Value as a Practical Expedient (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 74 $ 473 $ — $ — $ 547 Interest rate derivatives — 17 — — 17 Investments in trusts: (b)(c) Domestic equity 754 202 — — 956 Foreign equity 143 167 — — 310 U.S. Treasury and government agency securities — 290 — — 290 Municipal bonds — 53 — — 53 Pooled funds – fixed income — 10 — — 10 Corporate bonds 1 490 — — 491 Mortgage and asset backed securities — 88 — — 88 Private equity — — — 156 156 Cash and cash equivalents 3 — — — 3 Other 42 25 — — 67 Cash equivalents 1,182 17 — — 1,199 Other investments 9 32 — — 41 Total $ 2,208 $ 1,864 $ — $ 156 $ 4,228 Liabilities: Energy-related derivatives (a) $ 3 $ 7 $ — $ — $ 10 Interest rate derivatives — 139 — — 139 Foreign currency derivatives — 130 — — 130 Contingent consideration — — 14 — 14 Other — 13 — — 13 Total $ 3 $ 289 $ 14 $ — $ 306 Fair Value Measurements Using: At March 31, 2022 Quoted Prices Significant Significant Net Asset Value as a Practical Expedient (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 128 $ — $ — $ 128 Nuclear decommissioning trusts: (b) Domestic equity 452 193 — — 645 Foreign equity 143 — — — 143 U.S. Treasury and government agency securities — 21 — — 21 Municipal bonds — 2 — — 2 Corporate bonds 1 253 — — 254 Mortgage and asset backed securities — 20 — — 20 Private equity — — — 156 156 Other 14 — — — 14 Cash equivalents 1,129 17 — — 1,146 Other investments — 32 — — 32 Total $ 1,739 $ 666 $ — $ 156 $ 2,561 Liabilities: Energy-related derivatives $ — $ 2 $ — $ — $ 2 Georgia Power Assets: Energy-related derivatives $ — $ 179 $ — $ — $ 179 Interest rate derivatives — 12 — — 12 Nuclear decommissioning trusts: (b)(c) Domestic equity 302 1 — — 303 Foreign equity — 165 — — 165 U.S. Treasury and government agency securities — 269 — — 269 Municipal bonds — 51 — — 51 Corporate bonds — 237 — — 237 Mortgage and asset backed securities — 68 — — 68 Other 28 25 — — 53 Total $ 330 $ 1,007 $ — $ — $ 1,337 Liabilities: Energy-related derivatives $ — $ 1 $ — $ — $ 1 Fair Value Measurements Using: At March 31, 2022 Quoted Prices Significant Significant Net Asset Value as a Practical Expedient (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 138 $ — $ — $ 138 Liabilities: Energy-related derivatives $ — $ 2 $ — $ — $ 2 Southern Power Assets: Energy-related derivatives $ — $ 8 $ — $ — $ 8 Liabilities: Foreign currency derivatives $ — $ 43 $ — $ — $ 43 Contingent consideration — — 14 — 14 Other — 13 — — 13 Total $ — $ 56 $ 14 $ — $ 70 Southern Company Gas Assets: Energy-related derivatives (a) $ 74 $ 20 $ — $ — $ 94 Non-qualified deferred compensation trusts: Domestic equity — 8 — — 8 Foreign equity — 2 — — 2 Pooled funds – fixed income — 10 — — 10 Cash equivalents 3 — — — 3 Total $ 77 $ 40 $ — $ — $ 117 Liabilities: Energy-related derivatives (a) $ 3 $ 1 $ — $ — $ 4 Interest rate derivatives — 36 — — 36 Total $ 3 $ 37 $ — $ — $ 40 (a) Excludes cash collateral of $36 million. (b) Excludes receivables related to investment income, pending investment sales, payables related to pending investment purchases, and currencies. See Note 6 to the financial statements in Item 8 of the Form 10-K for additional information. (c) Includes investment securities pledged to creditors and collateral received and excludes payables related to the securities lending program. At March 31, 2022, approximately $72 million of the fair market value of Georgia Power's nuclear decommissioning trust funds' securities were on loan to creditors under the funds' managers' securities lending program. See Note 6 to the financial statements in Item 8 of the Form 10-K for additional information.
Schedule of Increase (Decrease) In Fair Value Of Funds	The fair value of the funds, including reinvested interest and dividends and excluding the funds' expenses, increased (decreased) by the amounts shown in the table below for the three months ended March 31, 2022 and 2021. The changes were recorded as a change to the regulatory assets and liabilities related to AROs for Georgia Power and Alabama Power, respectively. Fair value increases (decreases) Three Months Ended March 31, 2022 Three Months Ended March 31, 2021 (in millions) Southern Company $ (150) $ 39 Alabama Power (67) 41 Georgia Power (83) (2)
Schedule of Financial Instruments for which Carrying Amount Did Not Equal Fair Value	At March 31, 2022, other financial instruments for which the carrying amount did not equal fair value were as follows: Southern Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (*) (in billions) Long-term debt, including securities due within one year: Carrying amount $ 51.6 $ 9.8 $ 13.2 $ 1.5 $ 3.7 $ 6.9 Fair value 51.9 10.0 13.5 1.5 3.8 6.9 (*) 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)	3 Months Ended
	Mar. 31, 2022
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Energy-Related Derivatives	At March 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 (*) 279 2030 2025 Alabama Power 65 2025 — Georgia Power 75 2024 — Mississippi Power 71 2026 — Southern Power 4 2030 — Southern Company Gas (*) 64 2024 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 66.2 million mmBtu and short natural gas positions of 2.6 million mmBtu at March 31, 2022, which is also included in Southern Company's total volume.
Schedule of Interest Rate Derivatives	At March 31, 2022, the following interest rate derivatives were outstanding: Notional Interest Weighted Hedge Fair Value Gain (Loss) at March 31, 2022 (in millions) (in millions) Cash Flow Hedges of Forecasted Debt Georgia Power $ 200 1.87% — February 2032 $ 8 Georgia Power 100 2.27% — November 2051 4 Cash Flow Hedges of Existing Debt Southern Company parent 100 2.58% — April 2027 (1) Fair Value Hedges of Existing Debt Southern Company parent 400 1.75% 1-month LIBOR + 0.68% March 2028 (29) Southern Company parent 1,000 3.70% 1-month LIBOR + 2.36% April (69) Southern Company Gas 500 1.75% 1-month LIBOR + 0.38% January 2031 (35) Southern Company $ 2,300 $ (122)
Schedule of Foreign Currency Derivatives	At March 31, 2022, the following foreign currency derivatives were outstanding: Pay Notional Pay Receive Notional Receive Hedge Fair Value Gain (Loss) at March 31, 2022 (in millions) (in millions) (in millions) Fair Value Hedges of Existing Debt Southern Company parent $ 1,476 3.39% € 1,250 1.88% September 2027 $ (87) Cash Flow Hedges of Existing Debt Southern Power $ 677 2.95% € 600 1.00% June 2022 $ (24) Southern Power 564 3.78% 500 1.85% June 2026 (19) Southern Power total $ 1,241 € 1,100 $ (43) Southern Company $ 2,717 € 2,350 $ (130)
Schedule of Derivative Category and Balance Sheet Location	The fair value of energy-related derivatives, interest rate derivatives, and foreign currency derivatives was reflected in the balance sheets as follows: At March 31, 2022 At December 31, 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) (in millions) Southern Company Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 381 $ 1 $ 129 $ 30 Other deferred charges and assets/Other deferred credits and liabilities 116 6 72 6 Total derivatives designated as hedging instruments for regulatory purposes $ 497 $ 7 $ 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 $ 28 $ 2 $ 7 $ 5 Other deferred charges and assets/Other deferred credits and liabilities 5 — 1 — Interest rate derivatives: Assets from risk management activities/Other current liabilities 17 3 19 — Other deferred charges and assets/Other deferred credits and liabilities — 136 — 29 Foreign currency derivatives: Assets from risk management activities/Other current liabilities — 59 — 39 Other deferred charges and assets/Other deferred credits and liabilities — 71 — 40 Total derivatives designated as hedging instruments in cash flow and fair value hedges $ 50 $ 271 $ 27 $ 113 Derivatives not designated as hedging instruments Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 16 $ 2 $ 9 $ 4 Other deferred charges and assets/Other deferred credits and liabilities 1 — 1 — Total derivatives not designated as hedging instruments $ 17 $ 2 $ 10 $ 4 Gross amounts recognized $ 564 $ 280 $ 238 $ 153 Gross amounts offset (a) (45) (9) (25) (28) Net amounts recognized in the Balance Sheets (b) $ 519 $ 271 $ 213 $ 125 At March 31, 2022 At December 31, 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) (in millions) Alabama Power Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Other current assets/Other current liabilities $ 87 $ — $ 30 $ 9 Other deferred charges and assets/Other deferred credits and liabilities 41 2 25 2 Total derivatives designated as hedging instruments for regulatory purposes $ 128 $ 2 $ 55 $ 11 Gross amounts offset (2) (2) (5) (5) Net amounts recognized in the Balance Sheets $ 126 $ — $ 50 $ 6 Georgia Power Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 150 $ — $ 54 $ 6 Other deferred charges and assets/Other deferred credits and liabilities 29 1 21 2 Total derivatives designated as hedging instruments for regulatory purposes $ 179 $ 1 $ 75 $ 8 Derivatives designated as hedging instruments in cash flow and fair value hedges Interest rate derivatives: Assets from risk management activities/Other current liabilities $ 12 $ — $ — $ — Total derivatives designated as hedging instruments in cash flow and fair value hedges $ 12 $ — $ — $ — Gross amounts recognized $ 191 $ 1 $ 75 $ 8 Gross amounts offset (1) (1) (8) (8) Net amounts recognized in the Balance Sheets $ 190 $ — $ 67 $ — Mississippi Power Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 94 $ — $ 30 $ 3 Other deferred charges and assets/Other deferred credits and liabilities 44 2 26 2 Total derivatives designated as hedging instruments for regulatory purposes $ 138 $ 2 $ 56 $ 5 Gross amounts offset (2) (2) (4) (4) Net amounts recognized in the Balance Sheets $ 136 $ — $ 52 $ 1 At March 31, 2022 At December 31, 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) (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 $ 3 $ — $ 2 $ — Other deferred charges and assets/Other deferred credits and liabilities 3 — 1 — Foreign currency derivatives: Other current assets/Other current liabilities — 35 — 16 Other deferred charges and assets/Other deferred credits and liabilities — 8 — — Total derivatives designated as hedging instruments in cash flow and fair value hedges $ 6 $ 43 $ 3 $ 16 Derivatives not designated as hedging instruments Energy-related derivatives: Other current assets/Other current liabilities $ 2 $ — $ 1 $ — Gross amounts recognized $ 8 $ 43 $ 4 $ 16 Gross amounts offset — — — — Net amounts recognized in the Balance Sheets $ 8 $ 43 $ 4 $ 16 At March 31, 2022 At December 31, 2021 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) (in millions) Southern Company Gas Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 49 $ 1 $ 15 $ 12 Other deferred charges and assets/Other deferred credits and liabilities 3 — — — Total derivatives designated as hedging instruments for regulatory purposes $ 52 $ 1 $ 15 $ 12 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 25 $ 2 $ 5 $ 5 Other deferred charges and assets/Other deferred credits and liabilities 2 — — — Interest rate derivatives: Assets from risk management activities/Liabilities from risk management activities-current — — 6 — Other deferred charges and assets/Other deferred credits and liabilities — 36 — 6 Total derivatives designated as hedging instruments in cash flow and fair value hedges $ 27 $ 38 $ 11 $ 11 Derivatives not designated as hedging instruments Energy-related derivatives: Assets from risk management activities/Other current liabilities $ 14 $ 1 $ 8 $ 4 Other deferred charges and assets/Other deferred credits and liabilities 1 — 1 — Total derivatives not designated as hedging instruments $ 15 $ 1 $ 9 $ 4 Gross amounts recognized $ 94 $ 40 $ 35 $ 27 Gross amounts offset (a) (40) (4) (8) (11) Net amounts recognized in the Balance Sheets (b) $ 54 $ 36 $ 27 $ 16 (a) Gross amounts offset include cash collateral held on deposit in broker margin accounts of $36 million and $3 million at March 31, 2022 and December 31, 2021, respectively. (b) Net amounts of derivative instruments outstanding exclude immaterial premium and intrinsic value associated with weather derivatives for both periods presented.
Schedule of Pre-tax Effects of Unrealized Derivative Gains (Losses)	At March 31, 2022 and December 31, 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 Sheet Derivative Category and Balance Sheet Southern Alabama Georgia Mississippi Southern Company Gas (in millions) At March 31, 2022: Energy-related derivatives: Other regulatory liabilities, current $ 353 $ 87 $ 150 $ 94 $ 22 Other regulatory liabilities, deferred 111 39 28 42 2 Total energy-related derivative gains (losses) $ 464 $ 126 $ 178 $ 136 $ 24 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)
Schedule of Pre-Tax Effects of Hedging on AOCI	For the three months ended March 31, 2022 and 2021, the pre-tax effects of cash flow and fair value hedge accounting on accumulated OCI were as follows: Gain (Loss) Recognized in OCI on Derivative For the Three Months Ended March 31, 2022 2021 (in millions) Southern Company Cash flow hedges: Energy-related derivatives $ 42 $ 5 Interest rate derivatives 9 3 Foreign currency derivatives (28) (47) Fair value hedges (*) : Foreign currency derivatives 4 — Total $ 27 $ (39) Georgia Power Cash flow hedges: Interest rate derivatives $ 12 $ — Southern Power Cash flow hedges: Energy-related derivatives $ 5 $ 4 Foreign currency derivatives (28) (47) Total $ (23) $ (43) Southern Company Gas Cash flow hedges: Energy-related derivatives $ 37 $ 1 (*) Represents amounts excluded from the assessment of effectiveness for which the difference between changes in fair value and periodic amortization is recorded in OCI.
Schedule of Pre-Tax Effects of Cash Flow and Fair Value Hedging on Income	For the three months ended March 31, 2022 and 2021, the pre-tax effects of cash flow and fair value hedge accounting on income were as follows: Location and Amount of Gain (Loss) Recognized in Income on Cash Flow and Fair Value Hedging Relationships For the Three Months Ended March 31, 2022 2021 (in millions) Southern Company Total cost of natural gas $ 1,095 $ 583 Gain (loss) on energy-related cash flow hedges (a) 9 (3) Total depreciation and amortization 892 871 Gain (loss) on energy-related cash flow hedges (a) 2 3 Total interest expense, net of amounts capitalized (462) (450) Gain (loss) on interest rate cash flow hedges (a) (7) (7) Gain (loss) on foreign currency cash flow hedges (a) (6) (6) Gain (loss) on interest rate fair value hedges (b) (123) (10) Total other income (expense), net 145 58 Gain (loss) on foreign currency cash flow hedges (a)(c) (25) (60) Gain (loss) on foreign currency fair value hedges (24) — Amount excluded from effectiveness testing recognized in earnings (4) — Southern Power Total depreciation and amortization $ 120 $ 119 Gain (loss) on energy-related cash flow hedges (a) 2 3 Total interest expense, net of amounts capitalized (37) (38) Gain (loss) on foreign currency cash flow hedges (a) (6) (6) Total other income (expense), net 2 7 Gain (loss) on foreign currency cash flow hedges (a)(c) (25) (60) Southern Company Gas Total cost of natural gas $ 1,095 $ 583 Gain (loss) on energy-related cash flow hedges (a) 9 — Total interest expense, net of amounts capitalized (61) (60) Gain (loss) on interest rate cash flow hedges (a) (1) — Gain (loss) on interest rate fair value hedges (b) (36) — (a) Reclassified from accumulated OCI 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 accumulated OCI 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 Cumulative Basis Adjustments for Fair Value Hedges	At March 31, 2022 and December 31, 2021, the following amounts were recorded on the balance sheets related to cumulative basis adjustments for fair value hedges: Carrying Amount of the Hedged Item Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item Balance Sheet Location of Hedged Items At March 31, 2022 At December 31, 2021 At March 31, 2022 At December 31, 2021 (in millions) (in millions) Southern Company Long-term debt $ (3,136) $ (3,280) $ 126 $ 9 Southern Company Gas Long-term debt $ (459) $ (493) $ 37 $ 2
Schedule of Pre-tax Effect of Interest Rate and Energy Related Derivatives on Income	For the three months ended March 31, 2022 and 2021, 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 were as follows: Gain (Loss) Three Months Ended March 31, Derivatives in Non-Designated Hedging Relationships Statements of Income Location 2022 2021 (in millions) Energy-related derivatives: Natural gas revenues (*) $ 2 $ (17) Cost of natural gas 21 7 Total derivatives in non-designated hedging relationships $ 23 $ (10) (*) Excludes immaterial gains (losses) recorded in natural gas revenues associated with weather derivatives for all periods presented.

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	3 Months Ended
	Mar. 31, 2022
Business Combination and Asset Acquisition [Abstract]
Schedule of Construction Projects	Project Facility Resource Approximate Nameplate Capacity ( MW ) Location COD PPA Contract Period Projects Completed During the Three Months Ended March 31, 2022 Garland Solar Storage (a) Battery energy storage system 88 Kern County, CA September 2021 through February 2022 (b) 20 years Tranquillity Solar Storage (a) Battery energy storage system 72 Fresno County, CA November 2021 through March 2022 (c) 20 years (a) 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.

Segment and Related Informati_2

Segment and Related Information (Tables)	3 Months Ended
	Mar. 31, 2022
Segment Reporting [Abstract]
Schedule of Financial Data for Business Segments	Financial data for business segments and products and services for the three months ended March 31, 2022 and 2021 was as follows: Electric Utilities Traditional Southern Eliminations Total Southern Company Gas All Eliminations Consolidated (in millions) Three Months Ended March 31, 2022 Operating revenues $ 4,191 $ 539 $ (221) $ 4,509 $ 2,058 $ 123 $ (42) $ 6,648 Segment net income (loss) (a) 774 72 — 846 319 (125) (8) 1,032 At March 31, 2022 Goodwill $ — $ 2 $ — $ 2 $ 5,015 $ 263 $ — $ 5,280 Total assets 90,460 13,766 (627) 103,599 23,377 4,236 (2,573) 128,639 Three Months Ended March 31, 2021 Operating revenues $ 3,764 $ 440 $ (87) $ 4,117 $ 1,694 $ 134 $ (35) $ 5,910 Segment net income (loss) (a)(b)(c) 756 97 — 853 398 (108) (8) 1,135 At December 31, 2021 Goodwill $ — $ 2 $ — $ 2 $ 5,015 $ 263 $ — $ 5,280 Total assets 89,051 13,390 (667) 101,774 23,560 2,975 (775) 127,534 (a) Attributable to Southern Company. (b) For the traditional electric operating companies, includes a pre-tax charge of $48 million ($36 million after tax) at Georgia Power for estimated losses associated with the construction of Plant Vogtle Units 3 and 4. See Note (B) and Note 2 to the financial statements in Item 8 of the Form 10-K under "Georgia Power – Nuclear Construction" for additional information. (c) 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 Note 15 to the financial statements under "Southern Power – Development Projects" in Item 8 of the Form 10-K for additional information. Business segment financial data for the three months ended March 31, 2022 and 2021 was as follows: Gas Distribution Operations Gas Pipeline Investments Wholesale Gas Services (*) Gas Marketing Services Total All Other Eliminations Consolidated (in millions) Three Months Ended March 31, 2022 Operating revenues $ 1,803 $ 8 $ — $ 243 $ 2,054 $ 16 $ (12) $ 2,058 Segment net income (loss) 214 29 — 66 309 10 — 319 Total assets at March 31, 2022 21,034 1,473 — 1,640 24,147 12,017 (12,787) 23,377 Three Months Ended March 31, 2021 Operating revenues $ 1,200 $ 8 $ 298 $ 195 $ 1,701 $ 7 $ (14) $ 1,694 Segment net income (loss) 183 29 126 56 394 4 — 398 Total assets at December 31, 2021 20,917 1,467 31 1,556 23,971 12,114 (12,525) 23,560 (*) As a result of the sale of Sequent, wholesale gas services is no longer a reportable segment for the three months ended March 31, 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) Three Months Ended March 31, 2021 $ 2,588 $ 63 $ 2,651 $ 2,353 $ 298
Schedule of Financial Data for Products and Services	Electric Utilities' Revenues Retail Wholesale Other Total (in millions) Three Months Ended March 31, 2022 $ 3,613 $ 664 $ 232 $ 4,509 Three Months Ended March 31, 2021 3,342 545 230 4,117 Southern Company Gas' Revenues Gas Wholesale Gas Services (*) Gas Other Total (in millions) Three Months Ended March 31, 2022 $ 1,791 $ — $ 243 $ 24 $ 2,058 Three Months Ended March 31, 2021 1,192 298 195 9 1,694 (*) Prior to the sale of Sequent, the revenues for wholesale gas services were netted with costs associated with its energy and risk management activities. See "Southern Company Gas" herein and Note 15 to the financial statements under "Southern Company Gas" in Item 8 of the Form 10-K for additional information.

Introduction - Schedule of Good

Introduction - Schedule of Goodwill (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Goodwill [Line Items]
Goodwill	$ 5,280	$ 5,280
SOUTHERN Co GAS
Goodwill [Line Items]
Goodwill	5,015	5,015
SOUTHERN Co GAS | Gas distribution operations
Goodwill [Line Items]
Goodwill	4,034	4,034
SOUTHERN Co GAS | Gas marketing services
Goodwill [Line Items]
Goodwill	$ 981	$ 981

Introduction - Schedule of Othe

Introduction - Schedule of Other Intangible Assets (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Other intangible assets subject to amortization:
Gross Carrying Amount	$ 677	$ 677
Accumulated Amortization	(317)	(307)
Other Intangible Assets, Net	360	370
Other intangible assets not subject to amortization:
Federal Communications Commission licenses	75	75
Total other intangible assets
Gross Carrying Amount	752	752
Accumulated Amortization	(317)	(307)
Other Intangible Assets, Net	435	445
Customer relationships
Other intangible assets subject to amortization:
Gross Carrying Amount	212	212
Accumulated Amortization	(152)	(150)
Other Intangible Assets, Net	60	62
Total other intangible assets
Accumulated Amortization	(152)	(150)
Trade names
Other intangible assets subject to amortization:
Gross Carrying Amount	64	64
Accumulated Amortization	(41)	(38)
Other Intangible Assets, Net	23	26
Total other intangible assets
Accumulated Amortization	(41)	(38)
PPA fair value adjustments
Other intangible assets subject to amortization:
Gross Carrying Amount	390	390
Accumulated Amortization	(114)	(109)
Other Intangible Assets, Net	276	281
Total other intangible assets
Accumulated Amortization	(114)	(109)
Other
Other intangible assets subject to amortization:
Gross Carrying Amount	11	11
Accumulated Amortization	(10)	(10)
Other Intangible Assets, Net	1	1
Total other intangible assets
Accumulated Amortization	(10)	(10)
SOUTHERN POWER CO
Other intangible assets subject to amortization:
Accumulated Amortization	(114)	(109)
Total other intangible assets
Accumulated Amortization	(114)	(109)
SOUTHERN POWER CO | PPA fair value adjustments
Other intangible assets subject to amortization:
Gross Carrying Amount	390	390
Accumulated Amortization	(114)	(109)
Other Intangible Assets, Net	276	281
Total other intangible assets
Accumulated Amortization	(114)	(109)
SOUTHERN Co GAS
Other intangible assets subject to amortization:
Gross Carrying Amount	182	182
Accumulated Amortization	(148)	(145)
Other Intangible Assets, Net	34	37
Total other intangible assets
Accumulated Amortization	(148)	(145)
Other Intangible Assets, Net	34	37
SOUTHERN Co GAS | Customer relationships
Other intangible assets subject to amortization:
Gross Carrying Amount	156	156
Accumulated Amortization	(132)	(130)
Other Intangible Assets, Net	24	26
Total other intangible assets
Accumulated Amortization	(132)	(130)
SOUTHERN Co GAS | Trade names
Other intangible assets subject to amortization:
Gross Carrying Amount	26	26
Accumulated Amortization	(16)	(15)
Other Intangible Assets, Net	10	11
Total other intangible assets
Accumulated Amortization	$ (16)	$ (15)

Introduction - Schedule of Amor

Introduction - Schedule of Amortization of Other Intangible Assets (Details) $ in Millions	3 Months Ended
	Mar. 31, 2022USD ($)
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 10
Decrease in operating revenues	5
SOUTHERN POWER CO
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	5
SOUTHERN Co GAS
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 3

Introduction - Schedule of Cash

Introduction - Schedule of Cash, Cash Equivalents, and Restricted Cash (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2021	Dec. 31, 2020
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 1,662	$ 1,798
Restricted cash:
Total cash, cash equivalents, and restricted cash	1,673	1,829	$ 1,801	$ 1,068
Other current assets
Restricted cash:
Restricted cash	2	2
Other deferred charges and assets
Restricted cash:
Restricted cash	9	29
SOUTHERN POWER CO
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	130	107
Restricted cash:
Total cash, cash equivalents, and restricted cash	139	135	343	182
SOUTHERN POWER CO | Other current assets
Restricted cash:
Restricted cash	0	0
SOUTHERN POWER CO | Other deferred charges and assets
Restricted cash:
Restricted cash	9	29
SOUTHERN POWER CO | Tax Equity Contributions | Garland
Restricted cash:
Restricted cash		19
SOUTHERN POWER CO | Estimated Construction Completion Costs | Deuel Harvest
Restricted cash:
Restricted cash	9	10
SOUTHERN Co GAS
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	31	45
Restricted cash:
Total cash, cash equivalents, and restricted cash	33	48	$ 311	$ 19
SOUTHERN Co GAS | Other current assets
Restricted cash:
Restricted cash	2	2
SOUTHERN Co GAS | Other deferred charges and assets
Restricted cash:
Restricted cash	$ 0	$ 0

Introduction - Depreciation and

Introduction - Depreciation and Amortization (Details)	Jan. 01, 2022	Dec. 31, 2021
Maximum | Wind Generating Facility | SOUTHERN POWER CO
Property, Plant and Equipment [Line Items]
Property, plant and equipment, useful life	35 years	30 years

Regulatory Matters - Schedule o

Regulatory Matters - Schedule of Cost Recovery Clauses (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Loss Contingencies [Line Items]
Natural gas cost under recovery	$ 306	$ 266
ALABAMA POWER CO | Other regulatory assets, deferred
Loss Contingencies [Line Items]
Rate CNP Compliance	12	16
Rate CNP PPA	84	84
Retail Energy Cost Recovery	46	126
GEORGIA POWER CO | Other deferred charges and assets
Loss Contingencies [Line Items]
Fuel Cost Recovery	494	410
MISSISSIPPI POWER CO | Other regulatory assets, deferred
Loss Contingencies [Line Items]
Ad Valorem Tax	33	37
MISSISSIPPI POWER CO | Other customer accounts receivable
Loss Contingencies [Line Items]
Fuel Cost Recovery	16	4
MISSISSIPPI POWER CO | Other regulatory assets, current
Loss Contingencies [Line Items]
Ad Valorem Tax	12	12
SOUTHERN Co GAS
Loss Contingencies [Line Items]
Natural gas cost under recovery	306	266
SOUTHERN Co GAS | Other regulatory assets, deferred
Loss Contingencies [Line Items]
Natural gas cost under recovery	44	207
SOUTHERN Co GAS | Other regulatory assets, current
Loss Contingencies [Line Items]
Natural gas cost under recovery	306	266
SOUTHERN Co GAS | Other regulatory liabilities, current
Loss Contingencies [Line Items]
Natural gas cost under recovery	$ 13	$ 0

Regulatory Matters - GPC Integr

Regulatory Matters - GPC Integrated Resource Plan (Details) - GEORGIA POWER CO	3 Months Ended
	Mar. 31, 2022MW
Public Utilities, General Disclosures [Line Items]
Approved capacity increase (in MWs)	970
Service date extension term	1 year

Regulatory Matters - GPC Nuclea

Regulatory Matters - GPC Nuclear Construction (Details) - GEORGIA POWER CO - Plant Vogtle Units 3 And 4 $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2022USD ($)	Dec. 31, 2012utilityMW	Aug. 31, 2018
Loss Contingencies [Line Items]
Proportionate ownership share	45.70%
Number of construction units approved | utility		2
Electric generating capacity in mega watts under consortium agreement | MW		1,100
Estimated cost to complete, construction contingency estimate, financing costs	$ 3,400
Estimated cost to complete, construction contingency estimate, financing costs, incurred to date	3,000
Construction contingency estimate	43
Base project capital cost forecast, monthly	60
Monthly AFUDC	$ 40
Percentage of ownership interest required for voting for continuing construction			90.00%
Vogtle Owners
Loss Contingencies [Line Items]
Period of notice required in the event letters of credit are not renewed	30 days
Minimum | COVID-19
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss, loss of productivity, term	3 months
Estimate of possible loss	$ 160
Maximum | COVID-19
Loss Contingencies [Line Items]
Loss contingency, estimate of possible loss, loss of productivity, term	4 months
Estimate of possible loss	$ 200

Regulatory Matters - GPC Nucl_2

Regulatory Matters - GPC Nuclear Construction Cost and Schedule (Details) - GEORGIA POWER CO $ in Millions	3 Months Ended
	Mar. 31, 2022USD ($)
Loss Contingencies [Line Items]
Pre-tax charge to income	$ 440
Plant Vogtle Units 3 And 4
Loss Contingencies [Line Items]
Base project capital cost forecast	10,294
Construction contingency estimate	107
Total project capital cost forecast	10,401
Net investment as of end of the period	(8,715)
Remaining estimate to complete	1,686
Estimated cost to complete, costs not shared with other owners	590
Expected capitalized costs	377
Capitalized interest accrued	221
Plant Vogtle Units 3 And 4 | Twenty Fifth Vogtle Construction Monitoring Report
Loss Contingencies [Line Items]
Guarantor obligations	1,700
Customer refund	$ 188

Regulatory Matters - GPC Amendm

Regulatory Matters - GPC Amendments to the Vogtle Joint Ownership Agreements (Details) - Georgia Power - USD ($) $ in Thousands	Jan. 11, 2018	Mar. 31, 2022	Aug. 31, 2018
Public Utilities, General Disclosures [Line Items]
Pre-tax charge to income		$ 440,000
After tax charge to income		328,000
Plant Vogtle Units 3 And 4
Public Utilities, General Disclosures [Line Items]
Production tax credits, aggregate purchase price, maximum		300,000
Preliminary estimated cost to complete		10,401,000
Additional construction capital costs	$ 3,300,000	$ 460,000
Remaining share of construction costs, agreement to pay, percentage		100.00%
Percentage of ownership interest required for voting for continuing construction			90.00%
Percentage of costs, disallowed for recovery		6.00%
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
Proportionate ownership share		45.70%
Plant Vogtle Units 3 And 4 | Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs		$ 100
Plant Vogtle Units 3 And 4 | Category I
Public Utilities, General Disclosures [Line Items]
Preliminary estimated cost to complete		8,400,000
Additional construction capital costs, threshold		$ 800,000
Plant Vogtle Units 3 And 4 | Category II
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs, responsibility to pay		55.70%
Additional construction capital costs		$ 80,000
Plant Vogtle Units 3 And 4 | Category II | Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs, responsibility to pay		44.30%
Plant Vogtle Units 3 And 4 | Category II | Minimum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold		$ 800,000
Plant Vogtle Units 3 And 4 | Category II | Maximum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold		$ 1,600,000
Plant Vogtle Units 3 And 4 | Category III
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs, responsibility to pay		65.70%
Additional construction capital costs		$ 100,000
Plant Vogtle Units 3 And 4 | Category III | Vogtle Owners
Public Utilities, General Disclosures [Line Items]
Percentage of construction costs, responsibility to pay		34.30%
Plant Vogtle Units 3 And 4 | Category III | Minimum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold		$ 1,600,000
Plant Vogtle Units 3 And 4 | Category III | Maximum
Public Utilities, General Disclosures [Line Items]
Additional construction capital costs, threshold		$ 2,100,000

Regulatory Matters - GPC Nucl_3

Regulatory Matters - GPC Nuclear Construction Regulatory Matters (Details) - Plant Vogtle Units 3 And 4 - Georgia Power $ in Millions

Feb. 17, 2022USD ($)

Jan. 01, 2022USD ($)

Jan. 01, 2021

Jan. 01, 2020

Jan. 11, 2018USD ($)

Jan. 01, 2016

Mar. 31, 2022USD ($)

Jun. 30, 2021USD ($)report

Dec. 31, 2023USD ($)

Dec. 31, 2022USD ($)

Dec. 31, 2021USD ($)

Dec. 31, 2009USD ($)

Jun. 30, 2018USD ($)

Dec. 31, 2013

Public Utilities, General Disclosures [Line Items]

Estimated in-service capital cost

$ 4,418

Financing costs collected, net of tax

$ 2,800

Requested decrease in tariff

$ 78

Additional construction capital costs

$ 3,300

$ 460

Payments for contractor settlement agreement

300

Amendment to estimated in-service capital cost

$ 5,680

Retail rate of return on common equity

10.95%

Public utilities, approved return on equity percentage

5.30%

8.30%

10.00%

Public utilities, approved return on equity, monthly percentage decrease

0.10%

Return on equity reduction, negative impact on earnings

$ 270

Increase to base capital cost forecast not seeking recovery

$ 700

Twenty Fourth Vogtle Construction Monitoring Report

Public Utilities, General Disclosures [Line Items]

Cost settlement agreement revised forecast, net of payments

$ 7,300

Twenty Fifth Vogtle Construction Monitoring Report

Public Utilities, General Disclosures [Line Items]

Number of approved construction management reports | report

25

Requested capital construction costs

$ 7,900

Guarantor obligations

1,700

Customer refund

$ 188

Twenty Sixth Vogtle Construction Monitoring Report

Public Utilities, General Disclosures [Line Items]

Requested capital construction costs

$ 584

Scenario, Forecast

Public Utilities, General Disclosures [Line Items]

Return on equity reduction, negative impact on earnings

$ 265

$ 300

Regulatory Matters - MPC (Detai

Regulatory Matters - MPC (Details) - MISSISSIPPI POWER CO - USD ($) $ in Millions	Apr. 13, 2022	Mar. 15, 2022	Jun. 08, 2021
Loss Contingencies [Line Items]
Approved rate increase, percentage		1.90%
Approved rate increase (decrease)			$ 18
Subsequent Event
Loss Contingencies [Line Items]
Approved rate increase (decrease)	$ 5

Regulatory Matters - GAS Schedu

Regulatory Matters - GAS Schedule of Infrastructure Replacement Programs and Capital Projects (Details) - SOUTHERN Co GAS $ in Millions	3 Months Ended
	Mar. 31, 2022USD ($)
Public Utilities, General Disclosures [Line Items]
Capital expenditures	$ 80
Investing in Illinois
Public Utilities, General Disclosures [Line Items]
Capital expenditures	51
Steps to Advance Virginia's Energy
Public Utilities, General Disclosures [Line Items]
Capital expenditures	14
System Reinforcement Rider
Public Utilities, General Disclosures [Line Items]
Capital expenditures	14
Pipeline Replacement Program
Public Utilities, General Disclosures [Line Items]
Capital expenditures	$ 1

Contingencies - General Litigat

Contingencies - General Litigation Matters (Details) - Pending Litigation $ in Millions	Mar. 11, 2022USD ($)	Feb. 07, 2022claim	Oct. 08, 2021claim	Mar. 31, 2019plaintiff	Dec. 31, 2018USD ($)plaintiffdefendant	Mar. 09, 2022claim	Dec. 31, 2017claim
Shareholder Derivative Lawsuits
Loss Contingencies [Line Items]
Pending number of claims							2
Settlement expense | $	$ 4.5
GEORGIA POWER CO | Class Action Lawsuit
Loss Contingencies [Line Items]
Pending number of claims						4
Complaints filed		4	3
MISSISSIPPI POWER CO | Purported Violations of Mississippi Consumer Protection Act
Loss Contingencies [Line Items]
Number of plaintiffs | plaintiff					10
Number of defendants | defendant					3
Number of additional plaintiffs | plaintiff				4
Underpayment of refunds | $					$ 23.5

Contingencies - Environmental R

Contingencies - Environmental Remediation (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
GEORGIA POWER CO
Loss Contingencies [Line Items]
Environmental remediation liability, current and former sites	$ 16	$ 17
SOUTHERN Co GAS
Loss Contingencies [Line Items]
Environmental remediation liability, current and former sites	$ 249	$ 249

Revenue from Contracts with C_3

Revenue from Contracts with Customers and Lease Income - Schedule of Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 6,258	$ 6,900
Total operating revenues	6,648	5,910
Retail electric revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	3,613	3,342
Retail electric revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3,456	3,277
Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,525	1,468
Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,178	1,117
Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	727	668
Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	26	24
Natural Gas
Disaggregation of Revenue [Line Items]
Total operating revenues	2,058	1,694
Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,784	1,185
Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,016	614
Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	270	170
Transportation
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	337	288
Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	32	16
Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	129	97
Other natural gas revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	259	1,791
Wholesale gas services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		1,590
Gas marketing services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	243	194
Other natural gas revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	16	7
Other revenue sources
Disaggregation of Revenue [Line Items]
Other revenues	390	1,306
Other adjustments
Disaggregation of Revenue [Line Items]
Other revenues		(2,296)
Wholesale Electric
Disaggregation of Revenue [Line Items]
Total operating revenues	664	545
Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	534	398
PPA energy revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	342	212
PPA capacity revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	134	119
Non-PPA revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	58	67
Other revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	225	249
ALABAMA POWER CO
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,546	1,475
Total operating revenues	1,649	1,559
ALABAMA POWER CO | Retail electric revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	1,379	1,352
ALABAMA POWER CO | Retail electric revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,336	1,325
ALABAMA POWER CO | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	634	628
ALABAMA POWER CO | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	375	372
ALABAMA POWER CO | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	323	320
ALABAMA POWER CO | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	4	5
ALABAMA POWER CO | Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ALABAMA POWER CO | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ALABAMA POWER CO | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ALABAMA POWER CO | Transportation
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ALABAMA POWER CO | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ALABAMA POWER CO | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ALABAMA POWER CO | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ALABAMA POWER CO | Wholesale gas services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		0
ALABAMA POWER CO | Gas marketing services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ALABAMA POWER CO | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
ALABAMA POWER CO | Other revenue sources
Disaggregation of Revenue [Line Items]
Other revenues	103	84
ALABAMA POWER CO | Other adjustments
Disaggregation of Revenue [Line Items]
Other revenues		0
ALABAMA POWER CO | Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	162	104
ALABAMA POWER CO | PPA energy revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	59	43
ALABAMA POWER CO | PPA capacity revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	39	29
ALABAMA POWER CO | Non-PPA revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	64	32
ALABAMA POWER CO | Other revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	48	46
GEORGIA POWER CO
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,061	1,911
Total operating revenues	2,208	1,970
GEORGIA POWER CO | Retail electric revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	2,017	1,787
GEORGIA POWER CO | Retail electric revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,913	1,763
GEORGIA POWER CO | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	821	776
GEORGIA POWER CO | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	738	686
GEORGIA POWER CO | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	334	284
GEORGIA POWER CO | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	20	17
GEORGIA POWER CO | Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
GEORGIA POWER CO | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
GEORGIA POWER CO | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
GEORGIA POWER CO | Transportation
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
GEORGIA POWER CO | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
GEORGIA POWER CO | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
GEORGIA POWER CO | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
GEORGIA POWER CO | Wholesale gas services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		0
GEORGIA POWER CO | Gas marketing services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
GEORGIA POWER CO | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
GEORGIA POWER CO | Other revenue sources
Disaggregation of Revenue [Line Items]
Other revenues	147	59
GEORGIA POWER CO | Other adjustments
Disaggregation of Revenue [Line Items]
Other revenues		0
GEORGIA POWER CO | Wholesale Electric
Disaggregation of Revenue [Line Items]
Total operating revenues	66	43
GEORGIA POWER CO | Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	53	35
GEORGIA POWER CO | PPA energy revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	32	13
GEORGIA POWER CO | PPA capacity revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	12	13
GEORGIA POWER CO | Non-PPA revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	9	9
GEORGIA POWER CO | Other revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	95	113
MISSISSIPPI POWER CO
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	324	292
Total operating revenues	335	307
MISSISSIPPI POWER CO | Retail electric revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	217	204
MISSISSIPPI POWER CO | Retail electric revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	207	189
MISSISSIPPI POWER CO | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	70	64
MISSISSIPPI POWER CO | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	65	59
MISSISSIPPI POWER CO | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	70	64
MISSISSIPPI POWER CO | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2	2
MISSISSIPPI POWER CO | Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
MISSISSIPPI POWER CO | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
MISSISSIPPI POWER CO | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
MISSISSIPPI POWER CO | Transportation
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
MISSISSIPPI POWER CO | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
MISSISSIPPI POWER CO | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
MISSISSIPPI POWER CO | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
MISSISSIPPI POWER CO | Wholesale gas services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		0
MISSISSIPPI POWER CO | Gas marketing services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
MISSISSIPPI POWER CO | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
MISSISSIPPI POWER CO | Other revenue sources
Disaggregation of Revenue [Line Items]
Other revenues	11	15
MISSISSIPPI POWER CO | Other adjustments
Disaggregation of Revenue [Line Items]
Other revenues		0
MISSISSIPPI POWER CO | Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	108	95
MISSISSIPPI POWER CO | PPA energy revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3	4
MISSISSIPPI POWER CO | PPA capacity revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	3	3
MISSISSIPPI POWER CO | Non-PPA revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	102	88
MISSISSIPPI POWER CO | Other revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	9	8
SOUTHERN POWER CO
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	413	296
Total operating revenues	539	440
SOUTHERN POWER CO | Retail electric revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Transportation
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Wholesale gas services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		0
SOUTHERN POWER CO | Gas marketing services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN POWER CO | Other revenue sources
Disaggregation of Revenue [Line Items]
Other revenues	126	144
SOUTHERN POWER CO | Other adjustments
Disaggregation of Revenue [Line Items]
Other revenues		0
SOUTHERN POWER CO | Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	405	292
SOUTHERN POWER CO | PPA energy revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	251	156
SOUTHERN POWER CO | PPA capacity revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	81	75
SOUTHERN POWER CO | Non-PPA revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	73	61
SOUTHERN POWER CO | Other revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	8	4
SOUTHERN Co GAS
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	2,043	2,976
Total operating revenues	2,058	1,694
SOUTHERN Co GAS | Retail electric revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN Co GAS | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN Co GAS | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN Co GAS | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN Co GAS | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN Co GAS | Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,784	1,185
SOUTHERN Co GAS | Residential
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	1,016	614
SOUTHERN Co GAS | Commercial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	270	170
SOUTHERN Co GAS | Transportation
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	337	288
SOUTHERN Co GAS | Industrial
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	32	16
SOUTHERN Co GAS | Other
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	129	97
SOUTHERN Co GAS | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	259	1,791
SOUTHERN Co GAS | Wholesale gas services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers		1,590
SOUTHERN Co GAS | Gas marketing services
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	243	194
SOUTHERN Co GAS | Other natural gas revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	16	7
SOUTHERN Co GAS | Other revenue sources
Disaggregation of Revenue [Line Items]
Other revenues	15	1,014
SOUTHERN Co GAS | Other adjustments
Disaggregation of Revenue [Line Items]
Other revenues		(2,296)
SOUTHERN Co GAS | Wholesale electric revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN Co GAS | PPA energy revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN Co GAS | PPA capacity revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN Co GAS | Non-PPA revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	0	0
SOUTHERN Co GAS | Other revenues
Disaggregation of Revenue [Line Items]
Total revenue from contracts with customers	$ 0	$ 0

Revenue from Contracts with C_4

Revenue from Contracts with Customers and Lease Income - Schedule of Contract Balances (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Accounts Receivable	$ 2,571	$ 2,504
Contract Assets	81	117
Contract Liabilities	72	57
ALABAMA POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	616	589
Contract Assets	2	2
Contract Liabilities	3	4
GEORGIA POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	695	736
Contract Assets	31	63
Contract Liabilities	13	14
MISSISSIPPI POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	85	73
Contract Assets	0	0
Contract Liabilities	2	0
SOUTHERN POWER CO
Disaggregation of Revenue [Line Items]
Accounts Receivable	128	149
Contract Assets	0	1
Contract Liabilities	1	1
SOUTHERN Co GAS
Disaggregation of Revenue [Line Items]
Accounts Receivable	865	753
Contract Assets	0	0
Contract Liabilities	$ 0	$ 0

Revenue from Contracts with C_5

Revenue from Contracts with Customers and Lease Income - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Disaggregation of Revenue [Line Items]
Contract assets	$ 81	$ 117
Contract liabilities	72	57
Unregulated Distributed Generation
Disaggregation of Revenue [Line Items]
Contract assets	47	50
Contract liabilities	$ 54	$ 39

Revenue from Contracts with C_6

Revenue from Contracts with Customers and Lease Income - Schedule of Remaining Performance Obligations (Details) $ in Millions	Mar. 31, 2022USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 529
Performance obligation, expected timing of satisfaction	3 months
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	$ 459
Performance obligation, 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	$ 351
Performance obligation, 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	$ 321
Performance obligation, 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	$ 307
Performance obligation, 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	$ 2,345
Performance obligation, expected timing of satisfaction
ALABAMA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 24
Performance obligation, expected timing of satisfaction	3 months
ALABAMA POWER CO | 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
Performance obligation, expected timing of satisfaction	1 year
ALABAMA POWER CO | 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
Performance obligation, expected timing of satisfaction	1 year
ALABAMA POWER CO | 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	$ 5
Performance obligation, expected timing of satisfaction	1 year
ALABAMA POWER CO | 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
Performance obligation, expected timing of satisfaction	1 year
ALABAMA POWER CO | 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
Performance obligation, expected timing of satisfaction
GEORGIA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 55
Performance obligation, expected timing of satisfaction	3 months
GEORGIA POWER CO | 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	$ 55
Performance obligation, expected timing of satisfaction	1 year
GEORGIA POWER CO | 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	$ 26
Performance obligation, expected timing of satisfaction	1 year
GEORGIA POWER CO | 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
Performance obligation, expected timing of satisfaction	1 year
GEORGIA POWER CO | 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
Performance obligation, expected timing of satisfaction	1 year
GEORGIA POWER CO | 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	$ 21
Performance obligation, expected timing of satisfaction
SOUTHERN POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-04-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 252
Performance obligation, expected timing of satisfaction	3 months
SOUTHERN POWER CO | 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	$ 294
Performance obligation, expected timing of satisfaction	1 year
SOUTHERN POWER CO | 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	$ 310
Performance obligation, expected timing of satisfaction	1 year
SOUTHERN POWER CO | 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	$ 294
Performance obligation, expected timing of satisfaction	1 year
SOUTHERN POWER CO | 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	$ 299
Performance obligation, expected timing of satisfaction	1 year
SOUTHERN POWER CO | 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	$ 2,339
Performance obligation, expected timing of satisfaction

Revenue from Contracts with C_7

Revenue from Contracts with Customers and Lease Income - Schedule of Lease Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	$ 6	$ 3
Lease income - operating leases	51	55
Variable lease income	84	84
Total lease income	141	142
ALABAMA POWER CO
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	0	0
Lease income - operating leases	20	21
Variable lease income	0	0
Total lease income	20	21
GEORGIA POWER CO
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	0	0
Lease income - operating leases	8	10
Variable lease income	0	0
Total lease income	8	10
MISSISSIPPI POWER CO
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	4	3
Lease income - operating leases	0	0
Variable lease income	0	0
Total lease income	4	3
SOUTHERN POWER CO
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	2	0
Lease income - operating leases	21	21
Variable lease income	90	90
Total lease income	113	111
SOUTHERN Co GAS
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	0	0
Lease income - operating leases	9	9
Variable lease income	0	0
Total lease income	$ 9	$ 9

Consolidated Entities and Equ_3

Consolidated Entities and Equity Method Investments - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2022USD ($)investor	Dec. 31, 2021USD ($)
Schedule of Equity Method Investments [Line Items]
Assets	$ 128,639	$ 127,534
Liabilities	95,719	94,967
Equity investments in unconsolidated subsidiaries	1,293	1,282
Southern Power
Schedule of Equity Method Investments [Line Items]
Assets	13,766	13,390
Liabilities	7,210	6,792
Equity investments in unconsolidated subsidiaries	56	86
Proceeds from sale of equity method investments	$ 31
SP Solar Holdings I, LP | Southern Power
Schedule of Equity Method Investments [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	67.00%
SP Solar Holdings I, LP | Global Atlantic
Schedule of Equity Method Investments [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	33.00%
Variable Interest Entity, Primary Beneficiary | SP Solar Holdings I, LP | Southern Power
Schedule of Equity Method Investments [Line Items]
Assets	$ 6,000	6,100
Liabilities	407	408
Noncontrolling interests related to other partners' interests	1,100	1,100
Variable Interest Entity, Primary Beneficiary | SP Wind | Southern Power
Schedule of Equity Method Investments [Line Items]
Assets	2,300	2,300
Liabilities	180	130
Noncontrolling interests related to other partners' interests	$ 41	41
Distribution made to limited partner, cash distributions paid, percentage	60.00%
Number of financial investors | investor	3
Variable Interest Entity, Primary Beneficiary | SP Wind | Financial Investors
Schedule of Equity Method Investments [Line Items]
Distribution made to limited partner, cash distributions paid, percentage	40.00%
Variable Interest Entity, Primary Beneficiary | Other Variable Interest Entities | Southern Power
Schedule of Equity Method Investments [Line Items]
Assets	$ 1,800	1,900
Liabilities	248	263
Noncontrolling interests related to other partners' interests	$ 876	$ 886

Consolidated Entities and Equ_4

Consolidated Entities and Equity Method Investments - Schedule of Equity Method Investments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Dec. 31, 2021
Schedule of Equity Method Investments [Line Items]
Investment Balance	$ 1,293	$ 1,282
SOUTHERN Co GAS
Schedule of Equity Method Investments [Line Items]
Investment Balance	1,178	1,173
SOUTHERN Co GAS | SNG
Schedule of Equity Method Investments [Line Items]
Investment Balance	1,138	1,129
SOUTHERN Co GAS | Other
Schedule of Equity Method Investments [Line Items]
Investment Balance	40	$ 44
SOUTHERN Co GAS | PennEast Pipeline
Schedule of Equity Method Investments [Line Items]
Distribution	$ 4

Consolidated Entities and Equ_5

Consolidated Entities and Equity Method Investments - Schedule of Earnings (Loss) from Equity Method Investments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Schedule of Equity Method Investments [Line Items]
Earnings from Equity Method Investments	$ 46	$ 45
SOUTHERN Co GAS
Schedule of Equity Method Investments [Line Items]
Earnings from Equity Method Investments	40	41
SOUTHERN Co GAS | SNG
Schedule of Equity Method Investments [Line Items]
Earnings from Equity Method Investments	39	38
SOUTHERN Co GAS | Other
Schedule of Equity Method Investments [Line Items]
Earnings from Equity Method Investments	$ 1	$ 3

Financing - Schedule of Credit

Financing - Schedule of Credit Arrangements (Details)	3 Months Ended
	Mar. 31, 2022USD ($)letter_of_credit
Line of Credit Facility [Line Items]
Expires, 2022	$ 280,000,000
Expires, 2024	700,000,000
Expires, 2025	125,000,000
Expires, 2026	6,550,000,000
Total	7,655,000,000
Unused	7,574,000,000
Expires within One Year	280,000,000
Southern Company parent
Line of Credit Facility [Line Items]
Expires, 2022	0
Expires, 2024	0
Expires, 2025	0
Expires, 2026	2,000,000,000
Total	2,000,000,000
Unused	1,998,000,000
Expires within One Year	0
ALABAMA POWER CO
Line of Credit Facility [Line Items]
Expires, 2022	0
Expires, 2024	550,000,000
Expires, 2025	0
Expires, 2026	700,000,000
Total	1,250,000,000
Unused	1,250,000,000
Expires within One Year	0
GEORGIA POWER CO
Line of Credit Facility [Line Items]
Expires, 2022	0
Expires, 2024	0
Expires, 2025	0
Expires, 2026	1,750,000,000
Total	1,750,000,000
Unused	1,726,000,000
Expires within One Year	0
MISSISSIPPI POWER CO
Line of Credit Facility [Line Items]
Expires, 2022	0
Expires, 2024	150,000,000
Expires, 2025	125,000,000
Expires, 2026	0
Total	275,000,000
Unused	255,000,000
Expires within One Year	0
SOUTHERN POWER CO
Line of Credit Facility [Line Items]
Expires, 2022	0
Expires, 2024	0
Expires, 2025	0
Expires, 2026	600,000,000
Total	600,000,000
Unused	568,000,000
Expires within One Year	$ 0
Letter of credits not included | letter_of_credit	2
SOUTHERN POWER CO | Continuing Letter of Credit Facility A
Line of Credit Facility [Line Items]
Expires, 2025	$ 75,000,000
Unused	11,000,000
Expires, 2023	75,000,000
SOUTHERN POWER CO | Continuing Letter of Credit Facility B
Line of Credit Facility [Line Items]
Unused	19,000,000
SOUTHERN Co GAS
Line of Credit Facility [Line Items]
Expires, 2022	250,000,000
Expires, 2024	0
Expires, 2025	0
Expires, 2026	1,500,000,000
Total	1,750,000,000
Unused	1,747,000,000
Expires within One Year	250,000,000
SEGCO
Line of Credit Facility [Line Items]
Expires, 2022	30,000,000
Expires, 2024	0
Expires, 2025	0
Expires, 2026	0
Total	30,000,000
Unused	30,000,000
Expires within One Year	30,000,000
Southern Company Gas Capital
Line of Credit Facility [Line Items]
Expires, 2026	800,000,000
Nicor Gas
Line of Credit Facility [Line Items]
Expires, 2026	$ 700,000,000

Financing - Narrative (Details)

Financing - Narrative (Details)	Mar. 31, 2022USD ($)
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	$ 7,655,000,000
Variable rate pollution control revenue bonds outstanding	1,500,000,000
MISSISSIPPI POWER CO
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	275,000,000
Variable rate pollution control revenue bonds outstanding	34,000,000
MISSISSIPPI POWER CO | Line of Credit | Revolving Credit Facility
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	125,000,000
ALABAMA POWER CO
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	1,250,000,000
Variable rate pollution control revenue bonds outstanding	789,000,000
GEORGIA POWER CO
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	1,750,000,000
Variable rate pollution control revenue bonds outstanding	672,000,000
Fixed rate pollution control revenue bonds outstanding	$ 330,000,000

Financing - Schedule of Shares

Financing - Schedule of Shares Used to Compute Diluted Earnings Per Share (Details) - shares shares in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Debt Disclosure [Abstract]
As reported shares (in shares)	1,063	1,060
Effect of stock-based compensation (in shares)	6	6
Diluted shares (in shares)	1,069	1,066

Income Taxes - Narrative (Detai

Income Taxes - Narrative (Details)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
MISSISSIPPI POWER CO
Income Tax Contingency [Line Items]
Effective tax (benefit) rate	16.40%	8.40%
SOUTHERN POWER CO
Income Tax Contingency [Line Items]
Effective tax (benefit) rate	(80.00%)	(17.30%)

Retirement Benefits (Details)

Retirement Benefits (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected future employer contributions, remainder of fiscal year	$ 0
Pension Plans and Postretirement Plans
Service cost	103,000,000	$ 109,000,000
Interest cost	102,000,000	87,000,000
Expected return on plan assets	(316,000,000)	(298,000,000)
Amortization:
Prior service costs	0	0
Regulatory asset	0	0
Net (gain)/loss	60,000,000	78,000,000
Net periodic pension cost (income)	(51,000,000)	(24,000,000)
Pension Plans | ALABAMA POWER CO
Pension Plans and Postretirement Plans
Service cost	25,000,000	26,000,000
Interest cost	24,000,000	20,000,000
Expected return on plan assets	(77,000,000)	(72,000,000)
Amortization:
Prior service costs	0	0
Regulatory asset	0	0
Net (gain)/loss	16,000,000	21,000,000
Net periodic pension cost (income)	(12,000,000)	(5,000,000)
Pension Plans | GEORGIA POWER CO
Pension Plans and Postretirement Plans
Service cost	26,000,000	28,000,000
Interest cost	31,000,000	26,000,000
Expected return on plan assets	(99,000,000)	(94,000,000)
Amortization:
Prior service costs	0	0
Regulatory asset	0	0
Net (gain)/loss	18,000,000	25,000,000
Net periodic pension cost (income)	(24,000,000)	(15,000,000)
Pension Plans | MISSISSIPPI POWER CO
Pension Plans and Postretirement Plans
Service cost	4,000,000	4,000,000
Interest cost	5,000,000	4,000,000
Expected return on plan assets	(15,000,000)	(14,000,000)
Amortization:
Prior service costs	0	0
Regulatory asset	0	0
Net (gain)/loss	3,000,000	4,000,000
Net periodic pension cost (income)	(3,000,000)	(2,000,000)
Pension Plans | SOUTHERN POWER CO
Pension Plans and Postretirement Plans
Service cost	2,000,000	2,000,000
Interest cost	2,000,000	1,000,000
Expected return on plan assets	(4,000,000)	(3,000,000)
Amortization:
Prior service costs	0	0
Regulatory asset	0	0
Net (gain)/loss	1,000,000	1,000,000
Net periodic pension cost (income)	1,000,000	1,000,000
Pension Plans | SOUTHERN Co GAS
Pension Plans and Postretirement Plans
Service cost	9,000,000	9,000,000
Interest cost	7,000,000	6,000,000
Expected return on plan assets	(22,000,000)	(21,000,000)
Amortization:
Prior service costs	(1,000,000)	(1,000,000)
Regulatory asset	4,000,000	4,000,000
Net (gain)/loss	2,000,000	3,000,000
Net periodic pension cost (income)	(1,000,000)	0
Postretirement Benefits
Pension Plans and Postretirement Plans
Service cost	6,000,000	6,000,000
Interest cost	10,000,000	8,000,000
Expected return on plan assets	(20,000,000)	(19,000,000)
Amortization:
Regulatory asset	0	0
Net (gain)/loss		1,000,000
Net periodic pension cost (income)	(4,000,000)	(4,000,000)
Postretirement Benefits | ALABAMA POWER CO
Pension Plans and Postretirement Plans
Service cost	1,000,000	1,000,000
Interest cost	3,000,000	2,000,000
Expected return on plan assets	(8,000,000)	(7,000,000)
Amortization:
Regulatory asset	0	0
Net (gain)/loss		0
Net periodic pension cost (income)	(4,000,000)	(4,000,000)
Postretirement Benefits | GEORGIA POWER CO
Pension Plans and Postretirement Plans
Service cost	2,000,000	2,000,000
Interest cost	4,000,000	3,000,000
Expected return on plan assets	(7,000,000)	(7,000,000)
Amortization:
Regulatory asset	0	0
Net (gain)/loss		1,000,000
Net periodic pension cost (income)	(1,000,000)	(1,000,000)
Postretirement Benefits | MISSISSIPPI POWER CO
Pension Plans and Postretirement Plans
Service cost	0	0
Interest cost	0	0
Expected return on plan assets	0	0
Amortization:
Regulatory asset	0	0
Net (gain)/loss		0
Net periodic pension cost (income)	0	0
Postretirement Benefits | SOUTHERN POWER CO
Pension Plans and Postretirement Plans
Service cost	0	0
Interest cost	0	0
Expected return on plan assets	0	0
Amortization:
Regulatory asset	0	0
Net (gain)/loss		0
Net periodic pension cost (income)	0	0
Postretirement Benefits | SOUTHERN Co GAS
Pension Plans and Postretirement Plans
Service cost	0	0
Interest cost	1,000,000	1,000,000
Expected return on plan assets	(2,000,000)	(2,000,000)
Amortization:
Regulatory asset	2,000,000	2,000,000
Net (gain)/loss		(1,000,000)
Net periodic pension cost (income)	$ 1,000,000	$ 0

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Assets and Liabilities Measured at Fair Value (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Assets:
Derivatives	$ 519	$ 213
Liabilities:
Derivatives	271	125
Other	13
Collateral already posted, assets, aggregate fair value	36
Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Other	0
Significant Other Observable Inputs (Level 2)
Liabilities:
Other	13
Significant Unobservable Inputs (Level 3)
Liabilities:
Other	0
ALABAMA POWER CO
Assets:
Derivatives	126	50
Liabilities:
Derivatives	0	6
GEORGIA POWER CO
Assets:
Derivatives	190	67
Investments in trusts	72
Liabilities:
Derivatives	0	0
MISSISSIPPI POWER CO
Assets:
Derivatives	136	52
Liabilities:
Derivatives	0	1
SOUTHERN POWER CO
Assets:
Derivatives	8	4
Liabilities:
Derivatives	43	16
Other	13
SOUTHERN POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Other	0
SOUTHERN POWER CO | Significant Other Observable Inputs (Level 2)
Liabilities:
Other	13
SOUTHERN POWER CO | Significant Unobservable Inputs (Level 3)
Liabilities:
Other	0
SOUTHERN Co GAS
Assets:
Derivatives	54	27
Liabilities:
Derivatives	36	16
Total
Collateral already posted, assets, aggregate fair value	36	$ 3
Fair Value, Measurements, Recurring
Assets:
Cash equivalents	1,199
Other investments	41
Total	4,228
Liabilities:
Contingent consideration	14
Total	306
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	1,182
Other investments	9
Total	2,208
Liabilities:
Contingent consideration	0
Total	3
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	17
Other investments	32
Total	1,864
Liabilities:
Contingent consideration	0
Total	289
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0
Other investments	0
Total	0
Liabilities:
Contingent consideration	14
Total	14
Fair Value, Measurements, Recurring | Net Asset Value as a Practical Expedient (NAV)
Assets:
Total	156
Fair Value, Measurements, Recurring | Energy-related derivatives
Assets:
Derivatives	547
Liabilities:
Derivatives	10
Fair Value, Measurements, Recurring | Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivatives	74
Liabilities:
Derivatives	3
Fair Value, Measurements, Recurring | Energy-related derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	473
Liabilities:
Derivatives	7
Fair Value, Measurements, Recurring | Energy-related derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | Interest rate derivatives
Assets:
Derivatives	17
Liabilities:
Derivatives	139
Fair Value, Measurements, Recurring | Interest rate derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | Interest rate derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	17
Liabilities:
Derivatives	139
Fair Value, Measurements, Recurring | Interest rate derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | Domestic equity
Assets:
Investments in trusts	956
Fair Value, Measurements, Recurring | Domestic equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	754
Fair Value, Measurements, Recurring | Domestic equity | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	202
Fair Value, Measurements, Recurring | Domestic equity | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Foreign equity
Assets:
Investments in trusts	310
Fair Value, Measurements, Recurring | Foreign equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	143
Fair Value, Measurements, Recurring | Foreign equity | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	167
Fair Value, Measurements, Recurring | Foreign equity | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | U.S. Treasury and government agency securities
Assets:
Investments in trusts	290
Fair Value, Measurements, Recurring | U.S. Treasury and government agency securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | U.S. Treasury and government agency securities | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	290
Fair Value, Measurements, Recurring | U.S. Treasury and government agency securities | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Municipal bonds
Assets:
Investments in trusts	53
Fair Value, Measurements, Recurring | Municipal bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Municipal bonds | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	53
Fair Value, Measurements, Recurring | Municipal bonds | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Pooled funds – fixed income
Assets:
Investments in trusts	10
Fair Value, Measurements, Recurring | Pooled funds – fixed income | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Pooled funds – fixed income | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	10
Fair Value, Measurements, Recurring | Pooled funds – fixed income | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Corporate bonds
Assets:
Investments in trusts	491
Fair Value, Measurements, Recurring | Corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	1
Fair Value, Measurements, Recurring | Corporate bonds | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	490
Fair Value, Measurements, Recurring | Corporate bonds | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Mortgage and asset backed securities
Assets:
Investments in trusts	88
Fair Value, Measurements, Recurring | Mortgage and asset backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Mortgage and asset backed securities | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	88
Fair Value, Measurements, Recurring | Mortgage and asset backed securities | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Private equity
Assets:
Investments in trusts	156
Fair Value, Measurements, Recurring | Private equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Private equity | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Private equity | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Private equity | Net Asset Value as a Practical Expedient (NAV)
Assets:
Investments in trusts	156
Fair Value, Measurements, Recurring | Cash and cash equivalents
Assets:
Investments in trusts	3
Fair Value, Measurements, Recurring | Cash and cash equivalents | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	3
Fair Value, Measurements, Recurring | Cash and cash equivalents | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Cash and cash equivalents | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Other
Assets:
Investments in trusts	67
Fair Value, Measurements, Recurring | Other | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	42
Fair Value, Measurements, Recurring | Other | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	25
Fair Value, Measurements, Recurring | Other | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | Foreign currency derivatives
Liabilities:
Derivatives	130
Fair Value, Measurements, Recurring | Foreign currency derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | Foreign currency derivatives | Significant Other Observable Inputs (Level 2)
Liabilities:
Derivatives	130
Fair Value, Measurements, Recurring | Foreign currency derivatives | Significant Unobservable Inputs (Level 3)
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO
Assets:
Cash equivalents	1,146
Other investments	32
Total	2,561
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	1,129
Other investments	0
Total	1,739
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	17
Other investments	32
Total	666
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0
Other investments	0
Total	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Net Asset Value as a Practical Expedient (NAV)
Assets:
Total	156
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Energy-related derivatives
Assets:
Derivatives	128
Liabilities:
Derivatives	2
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Energy-related derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	128
Liabilities:
Derivatives	2
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Energy-related derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Domestic equity
Assets:
Investments in trusts	645
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Domestic equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	452
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Domestic equity | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	193
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Domestic equity | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Foreign equity
Assets:
Investments in trusts	143
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Foreign equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	143
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Foreign equity | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Foreign equity | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | U.S. Treasury and government agency securities
Assets:
Investments in trusts	21
Fair Value, Measurements, Recurring | ALABAMA POWER CO | U.S. Treasury and government agency securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | U.S. Treasury and government agency securities | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	21
Fair Value, Measurements, Recurring | ALABAMA POWER CO | U.S. Treasury and government agency securities | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Municipal bonds
Assets:
Investments in trusts	2
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Municipal bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Municipal bonds | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	2
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Municipal bonds | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Corporate bonds
Assets:
Investments in trusts	254
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	1
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Corporate bonds | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	253
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Corporate bonds | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Mortgage and asset backed securities
Assets:
Investments in trusts	20
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Mortgage and asset backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Mortgage and asset backed securities | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	20
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Mortgage and asset backed securities | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Private equity
Assets:
Investments in trusts	156
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Private equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Private equity | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Private equity | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Private equity | Net Asset Value as a Practical Expedient (NAV)
Assets:
Investments in trusts	156
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Other
Assets:
Investments in trusts	14
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Other | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	14
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Other | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Other | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO
Assets:
Total	1,337
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total	330
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Other Observable Inputs (Level 2)
Assets:
Total	1,007
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Unobservable Inputs (Level 3)
Assets:
Total	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Energy-related derivatives
Assets:
Derivatives	179
Liabilities:
Derivatives	1
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Energy-related derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	179
Liabilities:
Derivatives	1
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Energy-related derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Interest rate derivatives
Assets:
Derivatives	12
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Interest rate derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivatives	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Interest rate derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	12
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Interest rate derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Domestic equity
Assets:
Investments in trusts	303
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Domestic equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	302
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Domestic equity | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	1
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Domestic equity | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Foreign equity
Assets:
Investments in trusts	165
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Foreign equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Foreign equity | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	165
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Foreign equity | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | U.S. Treasury and government agency securities
Assets:
Investments in trusts	269
Fair Value, Measurements, Recurring | GEORGIA POWER CO | U.S. Treasury and government agency securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | U.S. Treasury and government agency securities | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	269
Fair Value, Measurements, Recurring | GEORGIA POWER CO | U.S. Treasury and government agency securities | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Municipal bonds
Assets:
Investments in trusts	51
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Municipal bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Municipal bonds | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	51
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Municipal bonds | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Corporate bonds
Assets:
Investments in trusts	237
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Corporate bonds | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	237
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Corporate bonds | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Mortgage and asset backed securities
Assets:
Investments in trusts	68
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Mortgage and asset backed securities | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Mortgage and asset backed securities | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	68
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Mortgage and asset backed securities | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Other
Assets:
Investments in trusts	53
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Other | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	28
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Other | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	25
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Other | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | MISSISSIPPI POWER CO | Energy-related derivatives
Assets:
Derivatives	138
Liabilities:
Derivatives	2
Fair Value, Measurements, Recurring | MISSISSIPPI POWER CO | Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | MISSISSIPPI POWER CO | Energy-related derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	138
Liabilities:
Derivatives	2
Fair Value, Measurements, Recurring | MISSISSIPPI POWER CO | Energy-related derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | SOUTHERN POWER CO
Liabilities:
Contingent consideration	14
Total	70
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Contingent consideration	0
Total	0
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Significant Other Observable Inputs (Level 2)
Liabilities:
Contingent consideration	0
Total	56
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Significant Unobservable Inputs (Level 3)
Liabilities:
Contingent consideration	14
Total	14
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Energy-related derivatives
Assets:
Derivatives	8
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivatives	0
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Energy-related derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	8
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Energy-related derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	0
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Foreign currency derivatives
Liabilities:
Derivatives	43
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Foreign currency derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Foreign currency derivatives | Significant Other Observable Inputs (Level 2)
Liabilities:
Derivatives	43
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Foreign currency derivatives | Significant Unobservable Inputs (Level 3)
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS
Assets:
Total	117
Liabilities:
Total	40
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total	77
Liabilities:
Total	3
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Other Observable Inputs (Level 2)
Assets:
Total	40
Liabilities:
Total	37
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Unobservable Inputs (Level 3)
Assets:
Total	0
Liabilities:
Total	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Energy-related derivatives
Assets:
Derivatives	94
Liabilities:
Derivatives	4
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivatives	74
Liabilities:
Derivatives	3
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Energy-related derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	20
Liabilities:
Derivatives	1
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Energy-related derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Interest rate derivatives
Liabilities:
Derivatives	36
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Interest rate derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Interest rate derivatives | Significant Other Observable Inputs (Level 2)
Liabilities:
Derivatives	36
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Interest rate derivatives | Significant Unobservable Inputs (Level 3)
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Domestic equity
Assets:
Non-qualified deferred compensation trusts	8
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Domestic equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Non-qualified deferred compensation trusts	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Domestic equity | Significant Other Observable Inputs (Level 2)
Assets:
Non-qualified deferred compensation trusts	8
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Domestic equity | Significant Unobservable Inputs (Level 3)
Assets:
Non-qualified deferred compensation trusts	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Foreign equity
Assets:
Non-qualified deferred compensation trusts	2
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Foreign equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Non-qualified deferred compensation trusts	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Foreign equity | Significant Other Observable Inputs (Level 2)
Assets:
Non-qualified deferred compensation trusts	2
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Foreign equity | Significant Unobservable Inputs (Level 3)
Assets:
Non-qualified deferred compensation trusts	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Pooled funds – fixed income
Assets:
Non-qualified deferred compensation trusts	10
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Pooled funds – fixed income | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Non-qualified deferred compensation trusts	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Pooled funds – fixed income | Significant Other Observable Inputs (Level 2)
Assets:
Non-qualified deferred compensation trusts	10
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Pooled funds – fixed income | Significant Unobservable Inputs (Level 3)
Assets:
Non-qualified deferred compensation trusts	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Cash equivalents
Assets:
Non-qualified deferred compensation trusts	3
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Cash equivalents | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Non-qualified deferred compensation trusts	3
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Cash equivalents | Significant Other Observable Inputs (Level 2)
Assets:
Non-qualified deferred compensation trusts	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Cash equivalents | Significant Unobservable Inputs (Level 3)
Assets:
Non-qualified deferred compensation trusts	$ 0

Fair Value Measurements - Sch_2

Fair Value Measurements - Schedule of Increase (Decrease) In Fair Value Of Funds (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Fair Value, Option, Quantitative Disclosures [Line Items]
Increase (decrease) in fair value of funds	$ (150)	$ 39
ALABAMA POWER CO
Fair Value, Option, Quantitative Disclosures [Line Items]
Increase (decrease) in fair value of funds	(67)	41
GEORGIA POWER CO
Fair Value, Option, Quantitative Disclosures [Line Items]
Increase (decrease) in fair value of funds	$ (83)	$ (2)

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) - ALABAMA POWER CO - Private equity $ in Millions	Mar. 31, 2022USD ($)
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair value	$ 156
Unfunded commitments	$ 84

Fair Value Measurements - Sch_3

Fair Value Measurements - Schedule of Financial Instruments for which Carrying Amount did not Equal Fair Value (Details) $ in Millions	Mar. 31, 2022USD ($)
Long-term debt, including securities due within one year:
Carrying amount	$ 51,600
Fair value	51,900
ALABAMA POWER CO
Long-term debt, including securities due within one year:
Carrying amount	9,800
Fair value	10,000
GEORGIA POWER CO
Long-term debt, including securities due within one year:
Carrying amount	13,200
Fair value	13,500
MISSISSIPPI POWER CO
Long-term debt, including securities due within one year:
Carrying amount	1,500
Fair value	1,500
SOUTHERN POWER CO
Long-term debt, including securities due within one year:
Carrying amount	3,700
Fair value	3,800
SOUTHERN Co GAS
Long-term debt, including securities due within one year:
Carrying amount	6,900
Fair value	$ 6,900

Derivatives - Schedule of Energ

Derivatives - Schedule of Energy-Related Derivatives (Details) - Energy-related, Natural Gas MMBTU in Millions	Mar. 31, 2022MMBTU
Energy-related derivative contracts
Net Purchased mmBtu	279
ALABAMA POWER CO
Energy-related derivative contracts
Net Purchased mmBtu	65
GEORGIA POWER CO
Energy-related derivative contracts
Net Purchased mmBtu	75
MISSISSIPPI POWER CO
Energy-related derivative contracts
Net Purchased mmBtu	71
SOUTHERN POWER CO
Energy-related derivative contracts
Net Purchased mmBtu	4
SOUTHERN Co GAS
Energy-related derivative contracts
Net Purchased mmBtu	64
SOUTHERN Co GAS | Derivatives not designated as hedging instruments | Long
Energy-related derivative contracts
Derivative nonmonetary notional amount net long short position volume	66.2
SOUTHERN Co GAS | Derivatives not designated as hedging instruments | Short
Energy-related derivative contracts
Derivative nonmonetary notional amount net long short position volume	2.6

Derivatives - Narrative (Detail

Derivatives - Narrative (Details) MMBTU in Millions	3 Months Ended
	Mar. 31, 2022USD ($)MMBTU	Dec. 31, 2021USD ($)
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	18
Collateral already posted, assets, aggregate fair value	$ 36,000,000
Energy-related, Natural Gas
Derivative [Line Items]
Cash flow hedge gain (loss) to be reclassified within twelve months	29,000,000
Interest rate derivatives
Derivative [Line Items]
Cash flow hedge gain (loss) to be reclassified within twelve months	$ (20,000,000)
ALABAMA POWER CO
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	4
GEORGIA POWER CO
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	6
MISSISSIPPI POWER CO
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	3
SOUTHERN POWER CO
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	5
Foreign currency cash flow hedge gain (loss) to be reclassified during next 12 months	$ 17,000,000
Registrants | Derivative Counterparties
Derivative [Line Items]
Collateral already posted, assets, aggregate fair value	0
SOUTHERN Co GAS
Derivative [Line Items]
Collateral already posted, assets, aggregate fair value	36,000,000	$ 3,000,000
SOUTHERN Co GAS | Energy-related, Natural Gas
Derivative [Line Items]
Cash flow hedge gain (loss) to be reclassified within twelve months	$ 26,000,000

Derivatives - Schedule of Inter

Derivatives - Schedule of Interest Rate Derivatives (Details) - Interest rate derivatives $ in Millions	3 Months Ended
	Mar. 31, 2022USD ($)
Derivative [Line Items]
Notional Amount	$ 2,300
Fair Value Gain (Loss)	(122)
GEORGIA POWER CO | Cash Flow Hedges of Forecasted Debt | February 2032
Derivative [Line Items]
Notional Amount	$ 200
Interest Rate Received	1.87%
Weighted Average Interest Rate Paid	0.00%
Fair Value Gain (Loss)	$ 8
GEORGIA POWER CO | Cash Flow Hedges of Forecasted Debt | November 2051
Derivative [Line Items]
Notional Amount	$ 100
Interest Rate Received	2.27%
Weighted Average Interest Rate Paid	0.00%
Fair Value Gain (Loss)	$ 4
Southern Company parent | Cash Flow Hedges of Existing Debt
Derivative [Line Items]
Notional Amount	$ 100
Interest Rate Received	2.58%
Weighted Average Interest Rate Paid	0.00%
Fair Value Gain (Loss)	$ (1)
Southern Company parent | Fair Value Hedges of Existing Debt | March 2028
Derivative [Line Items]
Notional Amount	$ 400
Interest Rate Received	1.75%
Fair Value Gain (Loss)	$ (29)
Southern Company parent | Fair Value Hedges of Existing Debt | April 2030
Derivative [Line Items]
Notional Amount	$ 1,000
Interest Rate Received	3.70%
Fair Value Gain (Loss)	$ (69)
SOUTHERN Co GAS | Fair Value Hedges of Existing Debt
Derivative [Line Items]
Notional Amount	$ 500
Interest Rate Received	1.75%
Fair Value Gain (Loss)	$ (35)
London Interbank Offered Rate (LIBOR) | Southern Company parent | Fair Value Hedges of Existing Debt | March 2028
Derivative [Line Items]
Weighted Average Interest Rate Paid	0.68%
London Interbank Offered Rate (LIBOR) | Southern Company parent | Fair Value Hedges of Existing Debt | April 2030
Derivative [Line Items]
Weighted Average Interest Rate Paid	2.36%
London Interbank Offered Rate (LIBOR) | SOUTHERN Co GAS | Fair Value Hedges of Existing Debt
Derivative [Line Items]
Weighted Average Interest Rate Paid	0.38%

Derivatives - Schedule of Forei

Derivatives - Schedule of Foreign Currency Derivatives (Details) - 3 months ended Mar. 31, 2022 - Foreign currency derivatives € in Millions, $ in Millions	USD ($)	EUR (€)
Derivative [Line Items]
Pay Notional	$ 2,717
Receive Notional | €		€ 2,350
Fair Value Gain (Loss)	(130)
Fair Value Hedges of Existing Debt | Southern Company parent
Derivative [Line Items]
Pay Notional	$ 1,476
Pay Rate	3.39%
Receive Notional | €		1,250
Receive Rate	1.88%
Fair Value Gain (Loss)	$ (87)
Cash Flow Hedges of Existing Debt | SOUTHERN POWER CO
Derivative [Line Items]
Pay Notional	1,241
Receive Notional | €		1,100
Fair Value Gain (Loss)	(43)
Cash Flow Hedges of Existing Debt | SOUTHERN POWER CO | June 2022
Derivative [Line Items]
Pay Notional	$ 677
Pay Rate	2.95%
Receive Notional | €		600
Receive Rate	1.00%
Fair Value Gain (Loss)	$ (24)
Cash Flow Hedges of Existing Debt | SOUTHERN POWER CO | June 2026
Derivative [Line Items]
Pay Notional	$ 564
Pay Rate	3.78%
Receive Notional | €		€ 500
Receive Rate	1.85%
Fair Value Gain (Loss)	$ (19)

Derivatives - Schedule of Deriv

Derivatives - Schedule of Derivative Category and Balance Sheet Location (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	$ 564	$ 238
Derivative asset, Gross amounts offset	(45)	(25)
Derivative asset, net amounts recognized in the balance sheets	519	213
Derivative liability, gross amount recognized	280	153
Derivative liability, Gross amounts offset	(9)	(28)
Derivative liability, net amounts recognized in the balance sheets	271	125
Collateral already posted, assets, aggregate fair value	36
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	17	10
Derivative liability, gross amount recognized	2	4
Derivatives not designated as hedging instruments | Energy-related derivatives | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	16	9
Derivatives not designated as hedging instruments | Energy-related derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	2	4
Derivatives not designated as hedging instruments | Energy-related derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	1	1
Derivatives not designated as hedging instruments | Energy-related derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	0	0
Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	497	201
Derivative liability, gross amount recognized	7	36
Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	381	129
Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	1	30
Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	116	72
Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	6	6
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	50	27
Derivative liability, gross amount recognized	271	113
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	28	7
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	2	5
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	5	1
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	0	0
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	17	19
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	3	0
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	0	0
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	136	29
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	0	0
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	59	39
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	0	0
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	71	40
ALABAMA POWER CO
Derivatives, Fair Value [Line Items]
Derivative asset, Gross amounts offset	(2)	(5)
Derivative asset, net amounts recognized in the balance sheets	126	50
Derivative liability, Gross amounts offset	(2)	(5)
Derivative liability, net amounts recognized in the balance sheets	0	6
ALABAMA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	128	55
Derivative liability, gross amount recognized	2	11
ALABAMA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other current assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	87	30
ALABAMA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	0	9
ALABAMA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	41	25
ALABAMA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	2	2
GEORGIA POWER CO
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	191	75
Derivative asset, Gross amounts offset	(1)	(8)
Derivative asset, net amounts recognized in the balance sheets	190	67
Derivative liability, gross amount recognized	1	8
Derivative liability, Gross amounts offset	(1)	(8)
Derivative liability, net amounts recognized in the balance sheets	0	0
GEORGIA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	179	75
Derivative liability, gross amount recognized	1	8
GEORGIA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	150	54
GEORGIA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	0	6
GEORGIA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	29	21
GEORGIA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	1	2
GEORGIA POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	12	0
Derivative liability, gross amount recognized	0	0
GEORGIA POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	12	0
GEORGIA POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	0	0
MISSISSIPPI POWER CO
Derivatives, Fair Value [Line Items]
Derivative asset, Gross amounts offset	(2)	(4)
Derivative asset, net amounts recognized in the balance sheets	136	52
Derivative liability, Gross amounts offset	(2)	(4)
Derivative liability, net amounts recognized in the balance sheets	0	1
MISSISSIPPI POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	138	56
Derivative liability, gross amount recognized	2	5
MISSISSIPPI POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	94	30
MISSISSIPPI POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	0	3
MISSISSIPPI POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	44	26
MISSISSIPPI POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	2	2
SOUTHERN POWER CO
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	8	4
Derivative asset, Gross amounts offset	0	0
Derivative asset, net amounts recognized in the balance sheets	8	4
Derivative liability, gross amount recognized	43	16
Derivative liability, Gross amounts offset	0	0
Derivative liability, net amounts recognized in the balance sheets	43	16
SOUTHERN POWER CO | Derivatives not designated as hedging instruments | Energy-related derivatives | Other current assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	2	1
SOUTHERN POWER CO | Derivatives not designated as hedging instruments | Energy-related derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	0	0
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	6	3
Derivative liability, gross amount recognized	43	16
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other current assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	3	2
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	0	0
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	3	1
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	0	0
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Other current assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	0	0
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	35	16
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	0	0
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Foreign currency derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	8	0
SOUTHERN Co GAS
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	94	35
Derivative asset, Gross amounts offset	(40)	(8)
Derivative asset, net amounts recognized in the balance sheets	54	27
Derivative liability, gross amount recognized	40	27
Derivative liability, Gross amounts offset	(4)	(11)
Derivative liability, net amounts recognized in the balance sheets	36	16
Collateral already posted, assets, aggregate fair value	36	3
SOUTHERN Co GAS | Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	15	9
Derivative liability, gross amount recognized	1	4
SOUTHERN Co GAS | Derivatives not designated as hedging instruments | Energy-related derivatives | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	14	8
SOUTHERN Co GAS | Derivatives not designated as hedging instruments | Energy-related derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	1	4
SOUTHERN Co GAS | Derivatives not designated as hedging instruments | Energy-related derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	1	1
SOUTHERN Co GAS | Derivatives not designated as hedging instruments | Energy-related derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	0	0
SOUTHERN Co GAS | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	52	15
Derivative liability, gross amount recognized	1	12
SOUTHERN Co GAS | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	49	15
SOUTHERN Co GAS | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	1	12
SOUTHERN Co GAS | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	3	0
SOUTHERN Co GAS | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	0	0
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	27	11
Derivative liability, gross amount recognized	38	11
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	25	5
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	2	5
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	2	0
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Energy-related derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	0	0
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	0	6
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivative asset, gross amount recognized	0	0
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	36	6
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Interest rate derivatives | Liabilities from risk management activities
Derivatives, Fair Value [Line Items]
Derivative liability, gross amount recognized	$ 0	$ 0

Derivatives - Schedule of Pre-t

Derivatives - Schedule of Pre-tax Effects of Unrealized Derivative Gains (Losses) (Details) - Energy-related derivatives - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	$ 464	$ 155
Other regulatory liabilities, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	353	107
Other regulatory liabilities, deferred
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	111	65
Other regulatory assets, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)		(17)
ALABAMA POWER CO
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	126	44
ALABAMA POWER CO | Other regulatory liabilities, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	87	28
ALABAMA POWER CO | Other regulatory liabilities, deferred
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	39	22
ALABAMA POWER CO | Other regulatory assets, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)		(6)
GEORGIA POWER CO
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	178	67
GEORGIA POWER CO | Other regulatory liabilities, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	150	48
GEORGIA POWER CO | Other regulatory liabilities, deferred
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	28	19
GEORGIA POWER CO | Other regulatory assets, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)		0
MISSISSIPPI POWER CO
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	136	51
MISSISSIPPI POWER CO | Other regulatory liabilities, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	94	27
MISSISSIPPI POWER CO | Other regulatory liabilities, deferred
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	42	24
MISSISSIPPI POWER CO | Other regulatory assets, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)		0
SOUTHERN Co GAS
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	24	(7)
SOUTHERN Co GAS | Other regulatory liabilities, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	22	4
SOUTHERN Co GAS | Other regulatory liabilities, deferred
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	$ 2	0
SOUTHERN Co GAS | Other regulatory assets, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)		$ (11)

Derivatives - Schedule of Pre_2

Derivatives - Schedule of Pre-Tax Effects of Hedging on AOCI (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	$ 27	$ (39)
Cash Flow Hedging | Energy-related derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	42	5
Cash Flow Hedging | Interest rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	9	3
Cash Flow Hedging | Foreign currency derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	(28)	(47)
Fair Value Hedging | Foreign currency derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	4	0
GEORGIA POWER CO | Cash Flow Hedging | Interest rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	12	0
Southern Power
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	(23)	(43)
Southern Power | Cash Flow Hedging | Energy-related derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	5	4
Southern Power | Cash Flow Hedging | Foreign currency derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	(28)	(47)
SOUTHERN Co GAS | Cash Flow Hedging | Energy-related derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	$ 37	$ 1

Derivatives - Schedule of Pre_3

Derivatives - Schedule of Pre-Tax Effects of Cash Flow and Fair Value Hedging on Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Derivative [Line Items]
Depreciation and amortization	$ 892	$ 871
Total interest expense, net of amounts capitalized	(462)	(450)
Total other income (expense), net	145	58
Natural gas
Derivative [Line Items]
Total cost of sales	1,095	583
Other Income (Expense)
Derivative [Line Items]
Amount excluded from effectiveness testing recognized in earnings	(4)	0
Cash Flow Hedging | Energy-related derivatives | Cost of Sales
Derivative [Line Items]
Gain (loss) on hedges	9	(3)
Cash Flow Hedging | Energy-related derivatives | Depreciation and Amortization
Derivative [Line Items]
Gain (loss) on hedges	2	3
Cash Flow Hedging | Interest rate derivatives | Interest Expense
Derivative [Line Items]
Gain (loss) on hedges	(7)	(7)
Cash Flow Hedging | Foreign currency derivatives | Interest Expense
Derivative [Line Items]
Gain (loss) on hedges	(6)	(6)
Cash Flow Hedging | Foreign currency derivatives | Other Income (Expense)
Derivative [Line Items]
Gain (loss) on hedges	(25)	(60)
Fair Value Hedging | Interest rate derivatives | Interest Expense
Derivative [Line Items]
Gain (loss) on hedges	(123)	(10)
Fair Value Hedging | Foreign currency derivatives | Other Income (Expense)
Derivative [Line Items]
Gain (loss) on hedges	(24)	0
SOUTHERN POWER CO
Derivative [Line Items]
Depreciation and amortization	120	119
Total interest expense, net of amounts capitalized	(37)	(38)
Total other income (expense), net	2	7
SOUTHERN POWER CO | Cash Flow Hedging | Energy-related derivatives | Depreciation and Amortization
Derivative [Line Items]
Gain (loss) on hedges	2	3
SOUTHERN POWER CO | Cash Flow Hedging | Foreign currency derivatives | Interest Expense
Derivative [Line Items]
Gain (loss) on hedges	(6)	(6)
SOUTHERN POWER CO | Cash Flow Hedging | Foreign currency derivatives | Other Income (Expense)
Derivative [Line Items]
Gain (loss) on hedges	(25)	(60)
SOUTHERN Co GAS
Derivative [Line Items]
Depreciation and amortization	137	130
Total interest expense, net of amounts capitalized	(61)	(60)
Total other income (expense), net	16	(63)
SOUTHERN Co GAS | Natural gas
Derivative [Line Items]
Total cost of sales	1,095	583
SOUTHERN Co GAS | Cash Flow Hedging | Energy-related derivatives | Cost of Sales
Derivative [Line Items]
Gain (loss) on hedges	9	0
SOUTHERN Co GAS | Cash Flow Hedging | Interest rate derivatives | Interest Expense
Derivative [Line Items]
Gain (loss) on hedges	(1)	0
SOUTHERN Co GAS | Fair Value Hedging | Interest rate derivatives | Interest Expense
Derivative [Line Items]
Gain (loss) on hedges	$ (36)	$ 0

Derivatives - Schedule of Cumul

Derivatives - Schedule of Cumulative Basis Adjustments for Fair Value Hedges (Details) - Fair Value Hedging - Long-term debt - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Derivative [Line Items]
Carrying Amount of the Hedged Item	$ (3,136)	$ (3,280)
Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item	126	9
SOUTHERN Co GAS
Derivative [Line Items]
Carrying Amount of the Hedged Item	(459)	(493)
Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item	$ 37	$ 2

Derivatives - Schedule of Pre_4

Derivatives - Schedule of Pre-tax Effect of Interest Rate and Energy Related Derivatives on Income (Details) - Derivatives not designated as hedging instruments - Energy-related derivatives - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	$ 23	$ (10)
Natural gas revenues
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	2	(17)
Cost of natural gas
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	$ 21	$ 7

Acquisitions and Dispositions -

Acquisitions and Dispositions - Southern Power Narrative (Details) - SOUTHERN POWER CO - MW	1 Months Ended		3 Months Ended	12 Months Ended
	Mar. 31, 2022	Feb. 28, 2022	Mar. 31, 2022	Dec. 31, 2021
Tranquillity Solar Storage
Business Acquisition [Line Items]
Nameplate capacity placed in service (in MWs)	40		40	32
Garland Solar Storage
Business Acquisition [Line Items]
Nameplate capacity placed in service (in MWs)		15	15	73

Acquisitions and Dispositions_2

Acquisitions and Dispositions - Schedule of Construction Projects (Details) - SOUTHERN POWER CO - MW	1 Months Ended		3 Months Ended	4 Months Ended	6 Months Ended	12 Months Ended
	Mar. 31, 2022	Feb. 28, 2022	Mar. 31, 2022	Dec. 31, 2021	Mar. 31, 2022	Dec. 31, 2021
Garland Solar Storage
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)	88		88		88
PPA Contract Period				20 years
Nameplate capacity placed in service (in MWs)		15	15			73
Tranquillity Solar Storage
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)	72		72		72
PPA Contract Period					20 years
Nameplate capacity placed in service (in MWs)	40		40			32

Segment and Related Informati_3

Segment and Related Information - Narrative (Details) $ in Millions	3 Months Ended
	Mar. 31, 2022USD ($)statesegment	Mar. 31, 2021USD ($)
Segment Reporting Information [Line Items]
Number of states in which entity operates | state	3
Operating revenues	$ 6,258	$ 6,900
SOUTHERN POWER CO
Segment Reporting Information [Line Items]
Operating revenues	413	296
SOUTHERN POWER CO | Traditional Electric Operating Companies | Wholesale revenues, affiliates
Segment Reporting Information [Line Items]
Operating revenues	$ 105	81
SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Number of states in which entity operates | state	4
Operating revenues	$ 2,043	2,976
Number of reportable segments | segment	3
SOUTHERN Co GAS | SOUTHERN POWER CO | Natural gas
Segment Reporting Information [Line Items]
Operating revenues		$ 12
Southern Natural Gas Company, LLC | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Ownership percentage, equity method investment	50.00%
Dalton Pipeline | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Ownership percentage, equity method investment	50.00%
PennEast Pipeline | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Ownership percentage, equity method investment	20.00%

Segment and Related Informati_4

Segment and Related Information - Schedule of Financial Data for Business Segments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021	Dec. 31, 2021
Segment Reporting Information [Line Items]
Operating revenues	$ 6,648	$ 5,910
Net income	1,032	1,135
Goodwill	5,280		$ 5,280
Total assets	128,639		127,534
Estimated loss on Plant Vogtle Units 3 and 4	0	48
Gain on sale	20	41
GEORGIA POWER CO
Segment Reporting Information [Line Items]
Operating revenues	2,208	1,970
Total assets	49,206		48,461
Estimated loss on Plant Vogtle Units 3 and 4	0	48
Estimated loss on Plant Vogtle Units 3 and 4, net of tax		36
SOUTHERN POWER CO
Segment Reporting Information [Line Items]
Operating revenues	539	440
Segment net income (loss)	72	97
Total assets	13,766		13,390
Gain on sale	2	39
SOUTHERN POWER CO | Wind Generating Facility
Segment Reporting Information [Line Items]
Gain on sale		37
Gain on sale, net of tax		28
SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	2,058	1,694
Segment net income (loss)	319	398
Goodwill	5,015		5,015
Total assets	23,377		23,560
Electric Utilities
Segment Reporting Information [Line Items]
Operating revenues	4,509	4,117
SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	2,058	1,694
Gas distribution operations | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Goodwill	4,034		4,034
Wholesale Gas Services | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues		298
Gas marketing services | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Goodwill	981		981
Operating Segments | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	2,054	1,701
Segment net income (loss)	309	394
Total assets	24,147		23,971
Operating Segments | Electric Utilities
Segment Reporting Information [Line Items]
Operating revenues	4,509	4,117
Net income	846	853
Goodwill	2		2
Total assets	103,599		101,774
Operating Segments | Traditional Electric Operating Companies
Segment Reporting Information [Line Items]
Operating revenues	4,191	3,764
Net income	774	756
Goodwill	0		0
Total assets	90,460		89,051
Operating Segments | SOUTHERN POWER CO
Segment Reporting Information [Line Items]
Operating revenues	539	440
Net income	72	97
Goodwill	2		2
Total assets	13,766		13,390
Operating Segments | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	2,058	1,694
Net income	319	398
Goodwill	5,015		5,015
Total assets	23,377		23,560
Operating Segments | Gas distribution operations | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	1,803	1,200
Segment net income (loss)	214	183
Total assets	21,034		20,917
Operating Segments | Gas Pipeline Investments | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	8	8
Segment net income (loss)	29	29
Total assets	1,473		1,467
Operating Segments | Wholesale Gas Services | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	0	298
Segment net income (loss)	0	126
Total assets	0		31
Operating Segments | Gas marketing services | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	243	195
Segment net income (loss)	66	56
Total assets	1,640		1,556
Operating Segments | All Other
Segment Reporting Information [Line Items]
Operating revenues	123	134
Net income	(125)	(108)
Goodwill	263		263
Total assets	4,236		2,975
Operating Segments | All Other | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	16	7
Segment net income (loss)	10	4
Total assets	12,017		12,114
Eliminations
Segment Reporting Information [Line Items]
Operating revenues	(42)	(35)
Net income	(8)	(8)
Goodwill	0		0
Total assets	(2,573)		(775)
Eliminations | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	(12)	(14)
Segment net income (loss)	0	0
Total assets	(12,787)		(12,525)
Eliminations | Electric Utilities
Segment Reporting Information [Line Items]
Operating revenues	(221)	(87)
Net income	0	$ 0
Goodwill	0		0
Total assets	$ (627)		$ (667)

Segment and Related Informati_5

Segment and Related Information - Schedule of Financial Data for Products and Services (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Concentration Risk [Line Items]
Operating revenues	$ 6,648	$ 5,910
Retail
Concentration Risk [Line Items]
Operating revenues	3,613	3,342
Wholesale Electric
Concentration Risk [Line Items]
Operating revenues	664	545
Other
Concentration Risk [Line Items]
Operating revenues	177	170
Other revenues
Concentration Risk [Line Items]
Operating revenues	136	159
Less Gross Gas Costs	69	82
Natural Gas
Concentration Risk [Line Items]
Operating revenues	2,058	1,694
Electric Utilities
Concentration Risk [Line Items]
Operating revenues	4,509	4,117
Electric Utilities | Retail
Concentration Risk [Line Items]
Operating revenues	3,613	3,342
Electric Utilities | Wholesale Electric
Concentration Risk [Line Items]
Operating revenues	664	545
Electric Utilities | Other Revenue
Concentration Risk [Line Items]
Operating revenues	232	230
Southern Company Gas' Revenues
Concentration Risk [Line Items]
Operating revenues	2,058	1,694
Southern Company Gas' Revenues | Gas Distribution Operations
Concentration Risk [Line Items]
Operating revenues	1,791	1,192
Southern Company Gas' Revenues | Wholesale Gas Services
Concentration Risk [Line Items]
Operating revenues	0	298
Southern Company Gas' Revenues | Gas marketing services
Concentration Risk [Line Items]
Operating revenues	243	195
Southern Company Gas' Revenues | Other
Concentration Risk [Line Items]
Operating revenues	24	9
Southern Company Gas' Revenues
Concentration Risk [Line Items]
Operating revenues	$ 2,058	1,694
Southern Company Gas' Revenues | Wholesale Gas Services
Concentration Risk [Line Items]
Operating revenues		298
Less Gross Gas Costs		2,353
Third Party Gross Revenues | Southern Company Gas' Revenues | Wholesale Gas Services
Concentration Risk [Line Items]
Operating revenues		2,588
Intercompany Revenues | Southern Company Gas' Revenues | Wholesale Gas Services
Concentration Risk [Line Items]
Operating revenues		63
Total Gross Revenues | Southern Company Gas' Revenues | Wholesale Gas Services
Concentration Risk [Line Items]
Operating revenues		$ 2,651