Mississippi Power (MSPWP) 10-Q 31 Jul 19 2019 Q2 Quarterly report Financial data

Cover Page

Cover Page	6 Months Ended
	Jun. 30, 2019shares
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Jun. 30, 2019
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 Shell Company	false
Entity Common Stock, Shares Outstanding	1,045,231,646
Entity Central Index Key	0000092122
Amendment Flag	false
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q2
Current Fiscal Year End Date	--12-31
Entity Emerging Growth Company	false
Entity Small Business	false
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 2015A 6.25% Junior Subordinated Notes due 2075
Document Information [Line Items]
Title of 12(b) Security	Series 2015A 6.25% Junior Subordinated Notes due 2075
Trading Symbol	SOJA
Security Exchange Name	NYSE
Series 2016A 5.25% Junior Subordinated Notes due 2076
Document Information [Line Items]
Title of 12(b) Security	Series 2016A 5.25% Junior Subordinated Notes due 2076
Trading Symbol	SOJB
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
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
Title of 12(b) Security	5.00% Series Class A Preferred Stock
Trading Symbol	ALP PR Q
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Common Stock, Shares Outstanding	30,537,500
Entity Central Index Key	0000003153
Entity Emerging Growth Company	false
Entity Small Business	false
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
Title of 12(b) Security	Series 2017A 5.00% Junior Subordinated Notes due 2077
Trading Symbol	GPJA
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Shell Company	false
Entity Common Stock, Shares Outstanding	9,261,500
Entity Central Index Key	0000041091
Entity Emerging Growth Company	false
Entity Small Business	false
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 Shell Company	false
Entity Common Stock, Shares Outstanding	1,121,000
Entity Central Index Key	0000066904
Entity Emerging Growth Company	false
Entity Small Business	false
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 Shell Company	false
Entity Common Stock, Shares Outstanding	1,000
Entity Central Index Key	0001160661
Entity Emerging Growth Company	false
Entity Small Business	false
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 Shell Company	false
Entity Common Stock, Shares Outstanding	100
Entity Central Index Key	0001004155
Entity Emerging Growth Company	false
Entity Small Business	false

Condensed Consolidated Statemen

Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Operating Revenues:
Total operating revenues	$ 5,098	$ 5,627	$ 10,510	$ 11,999
Operating Expenses:
Other operations and maintenance	1,316	1,523	2,628	2,972
Depreciation and amortization	755	783	1,506	1,552
Taxes other than income taxes	299	316	628	671
Estimated loss on plants under construction	4	1,060	6	1,105
(Gain) loss on dispositions, net	(8)	36	(2,506)	36
Asset impairment			32	161
Goodwill impairment	32		32
Total operating expenses	3,756	5,564	5,477	10,560
Operating Income	1,342	63	5,033	1,439
Other Income and (Expense):
Allowance for equity funds used during construction	31	32	63	63
Earnings from equity method investments	33	31	81	72
Interest expense, net of amounts capitalized	(429)	(470)	(859)	(928)
Other income (expense), net	99	78	176	138
Total other income and (expense)	(266)	(329)	(539)	(655)
Earnings (Loss) Before Income Taxes	1,076	(266)	4,494	784
Income taxes (benefit)	145	(139)	1,505	(25)
Consolidated Net Income (Loss)	931	(127)	2,989	809
Dividends on preferred stock of subsidiaries	3	4	7	8
Net income attributable to noncontrolling interests	29	23	0	17
Net Income (Loss)	$ 899	$ (154)	$ 2,982	$ 784
Earnings (loss) per share -
Basic (in dollars per share)	$ 0.86	$ (0.15)	$ 2.86	$ 0.77
Diluted (in dollars per share)	$ 0.85	$ (0.15)	$ 2.84	$ 0.77
Average number of shares of common stock outstanding (in millions)
Basic (in shares)	1,044	1,014	1,041	1,012
Diluted (in shares)	1,052	1,014	1,049	1,017
Retail electric revenues
Operating Revenues:
Total operating revenues	$ 3,540	$ 3,740	$ 6,623	$ 7,308
Wholesale electric revenues
Operating Revenues:
Total operating revenues	542	616	1,041	1,239
Other electric revenues
Operating Revenues:
Total operating revenues	161	170	331	330
Natural gas
Operating Revenues:
Total operating revenues	689	706	2,163	2,314
Operating Expenses:
Total cost of natural gas	191	228	877	949
Other
Operating Revenues:
Total operating revenues	166	395	352	808
Operating Expenses:
Total cost of natural gas	84	279	203	568
Fuel
Operating Expenses:
Total cost of natural gas	914	1,103	1,764	2,204
Purchased power
Operating Expenses:
Total cost of natural gas	201	236	371	503
ALABAMA POWER CO
Operating Revenues:
Total operating revenues	1,513	1,503	2,921	2,976
Operating Expenses:
Other operations and maintenance	402	402	812	788
Depreciation and amortization	200	189	399	379
Taxes other than income taxes	98	94	200	192
Total operating expenses	1,068	1,123	2,138	2,224
Operating Income	445	380	783	752
Other Income and (Expense):
Allowance for equity funds used during construction	14	14	28	27
Interest expense, net of amounts capitalized	(82)	(80)	(165)	(158)
Other income (expense), net	11	12	25	15
Total other income and (expense)	(57)	(54)	(112)	(116)
Earnings (Loss) Before Income Taxes	388	326	671	636
Income taxes (benefit)	89	64	151	145
Consolidated Net Income (Loss)	299	262	520	491
Dividends on preferred stock of subsidiaries	3	3	7	7
Net Income (Loss)	296	259	513	484
ALABAMA POWER CO | Retail electric revenues
Operating Revenues:
Total operating revenues	1,378	1,338	2,592	2,624
ALABAMA POWER CO | Wholesale electric revenues
Operating Revenues:
Total operating revenues	62	65	123	139
ALABAMA POWER CO | Other
Operating Revenues:
Total operating revenues	69	69	143	131
ALABAMA POWER CO | Fuel
Operating Expenses:
Total cost of natural gas	252	347	553	672
ALABAMA POWER CO | Purchased power
Operating Expenses:
Total cost of natural gas	47	48	84	113
ALABAMA POWER CO | Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	4	31	63	82
ALABAMA POWER CO | Purchased power, affiliates
Operating Expenses:
Total cost of natural gas	69	43	90	80
GEORGIA POWER CO
Operating Revenues:
Total operating revenues	2,117	2,048	3,951	4,008
Operating Expenses:
Other operations and maintenance	463	457	913	863
Depreciation and amortization	244	230	483	458
Taxes other than income taxes	115	106	220	214
Estimated loss on plants under construction	0	1,060	0	1,060
Total operating expenses	1,470	2,520	2,857	3,967
Operating Income	647	(472)	1,094	41
Other Income and (Expense):
Interest expense, net of amounts capitalized	(105)	(102)	(201)	(208)
Other income (expense), net	35	35	77	73
Total other income and (expense)	(70)	(67)	(124)	(135)
Earnings (Loss) Before Income Taxes	577	(539)	970	(94)
Income taxes (benefit)	129	(143)	211	(50)
Consolidated Net Income (Loss)	448	(396)	759	(44)
Net Income (Loss)	448	(396)
GEORGIA POWER CO | Retail electric revenues
Operating Revenues:
Total operating revenues	1,946	1,889	3,614	3,688
GEORGIA POWER CO | Wholesale electric revenues
Operating Revenues:
Total operating revenues	33	36	62	80
GEORGIA POWER CO | Other
Operating Revenues:
Total operating revenues	135	120	270	227
GEORGIA POWER CO | Fuel
Operating Expenses:
Total cost of natural gas	390	378	689	790
GEORGIA POWER CO | Purchased power
Operating Expenses:
Total cost of natural gas	124	111	242	233
GEORGIA POWER CO | Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	3	3	5	13
GEORGIA POWER CO | Purchased power, affiliates
Operating Expenses:
Total cost of natural gas	134	178	310	349
MISSISSIPPI POWER CO
Operating Revenues:
Total operating revenues	313	297	600	598
Operating Expenses:
Other operations and maintenance	68	67	127	141
Depreciation and amortization	48	44	95	84
Taxes other than income taxes	28	27	55	54
Estimated loss on plants under construction	4	0	6	45
Total operating expenses	259	243	490	537
Operating Income	54	54	110	61
Other Income and (Expense):
Interest expense, net of amounts capitalized	(17)	(21)	(35)	(39)
Other income (expense), net	5	27	11	27
Total other income and (expense)	(12)	6	(24)	(12)
Earnings (Loss) Before Income Taxes	42	60	86	49
Income taxes (benefit)	5	13	12	9
Consolidated Net Income (Loss)	37	47	74	40
Dividends on preferred stock of subsidiaries	0	1	0	1
Net Income (Loss)	37	46	74	39
MISSISSIPPI POWER CO | Retail electric revenues
Operating Revenues:
Total operating revenues	215	212	418	406
MISSISSIPPI POWER CO | Wholesale electric revenues
Operating Revenues:
Total operating revenues	57	59	114	127
MISSISSIPPI POWER CO | Other
Operating Revenues:
Total operating revenues	4	7	10	11
MISSISSIPPI POWER CO | Fuel
Operating Expenses:
Total cost of natural gas	105	98	198	197
MISSISSIPPI POWER CO | Purchased power
Operating Expenses:
Total cost of natural gas	6	7	9	16
MISSISSIPPI POWER CO | Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	37	19	58	54
SOUTHERN POWER CO
Operating Revenues:
Total operating revenues	510	555	953	1,064
Operating Expenses:
Other operations and maintenance	79	91	166	184
Depreciation and amortization	119	125	237	240
Taxes other than income taxes	11	12	21	24
(Gain) loss on dispositions, net	(23)	0	(23)	0
Asset impairment	0	119	0	119
Total operating expenses	357	539	740	988
Operating Income	153	16	213	76
Other Income and (Expense):
Interest expense, net of amounts capitalized	(41)	(46)	(84)	(93)
Other income (expense), net	40	2	41	5
Total other income and (expense)	(1)	(44)	(43)	(88)
Earnings (Loss) Before Income Taxes	152	(28)	170	(12)
Income taxes (benefit)	(51)	(73)	(60)	(172)
Consolidated Net Income (Loss)	203	45	230	160
Net income attributable to noncontrolling interests	29	23	0	17
Net Income (Loss)	174	22	230	143
SOUTHERN POWER CO | Wholesale electric revenues
Operating Revenues:
Total operating revenues	390	443	743	867
SOUTHERN POWER CO | Other
Operating Revenues:
Total operating revenues	3	3	6	5
SOUTHERN POWER CO | Fuel
Operating Expenses:
Total cost of natural gas	139	153	284	321
SOUTHERN POWER CO | Purchased power
Operating Expenses:
Total cost of natural gas	32	39	55	100
SOUTHERN POWER CO | Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	117	109	204	192
SOUTHERN Co GAS
Operating Revenues:
Total operating revenues	689	730	2,163	2,369
Operating Expenses:
Other operations and maintenance	199	238	433	514
Depreciation and amortization	119	126	238	255
Taxes other than income taxes	46	48	128	125
(Gain) loss on dispositions, net	0	36	0	36
Goodwill impairment	0	0	0	42
Total operating expenses	555	681	1,676	1,933
Operating Income	134	49	487	436
Other Income and (Expense):
Earnings from equity method investments	31	31	80	74
Interest expense, net of amounts capitalized	(59)	(59)	(118)	(118)
Other income (expense), net	6	3	10	15
Total other income and (expense)	(22)	(25)	(28)	(29)
Earnings (Loss) Before Income Taxes	112	24	459	407
Income taxes (benefit)	6	55	83	159
Consolidated Net Income (Loss)	106	(31)	376	248
Net Income (Loss)	106	(31)	376	248
SOUTHERN Co GAS | Natural gas
Operating Revenues:
Total operating revenues	688	710	2,163	2,341
Operating Expenses:
Total cost of natural gas	191	228	877	949
SOUTHERN Co GAS | Other
Operating Revenues:
Total operating revenues	0	24	0	55
Operating Expenses:
Total cost of natural gas	0	5	0	12
SOUTHERN Co GAS | Alternative revenue programs
Operating Revenues:
Total operating revenues	$ 1	$ (4)	$ 0	$ (27)

Condensed Consolidated Statem_2

Condensed Consolidated Statements of Income (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Alternative revenue programs
Total operating revenues	$ 1	$ (4)	$ 0	$ (27)
SOUTHERN Co GAS
Excise taxes collected	$ 23	$ 23	$ 78	$ 74

Condensed Consolidated Statem_3

Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Net income (loss)	$ 931	$ (127)	$ 2,989	$ 809
Qualifying hedges:
Changes in fair value, net of tax	(32)	(54)	(60)	(8)
Reclassification adjustment for amounts included in net income, net of tax	(3)	64	24	45
Pension and other postretirement benefit plans:
Reclassification adjustment for amounts included in net income, net of tax	0	2	1	4
Total other comprehensive income (loss)	(35)	12	(35)	41
Comprehensive Income (Loss)	896	(115)	2,954	850
Dividends on preferred stock of subsidiaries	3	4	7	8
Comprehensive income attributable to noncontrolling interests	29	23	0	17
Comprehensive Income (Loss) Attributable to Parent	864	(142)	2,947	825
ALABAMA POWER CO
Net income (loss)	299	262	520	491
Qualifying hedges:
Reclassification adjustment for amounts included in net income, net of tax	1	1	2	2
Pension and other postretirement benefit plans:
Total other comprehensive income (loss)	1	1	2	2
Comprehensive Income (Loss)	300	263	522	493
Dividends on preferred stock of subsidiaries	3	3	7	7
GEORGIA POWER CO
Net income (loss)	448	(396)	759	(44)
Qualifying hedges:
Changes in fair value, net of tax	(28)	0	(28)	0
Reclassification adjustment for amounts included in net income, net of tax	1	1	1	2
Pension and other postretirement benefit plans:
Total other comprehensive income (loss)	(27)	1	(27)	2
Comprehensive Income (Loss)	421	(395)	732	(42)
MISSISSIPPI POWER CO
Net income (loss)	37	47	74	40
Qualifying hedges:
Changes in fair value, net of tax	0	0	0	(1)
Reclassification adjustment for amounts included in net income, net of tax	0	0	1	1
Pension and other postretirement benefit plans:
Total other comprehensive income (loss)	0	0	1	0
Comprehensive Income (Loss)	37	47	75	40
Dividends on preferred stock of subsidiaries	0	1	0	1
SOUTHERN POWER CO
Net income (loss)	203	45	230	160
Qualifying hedges:
Changes in fair value, net of tax	(1)	(55)	(30)	(8)
Reclassification adjustment for amounts included in net income, net of tax	(7)	59	17	35
Pension and other postretirement benefit plans:
Reclassification adjustment for amounts included in net income, net of tax	0	0	0	1
Total other comprehensive income (loss)	(8)	4	(13)	28
Comprehensive Income (Loss)	195	49	217	188
Comprehensive income attributable to noncontrolling interests	29	23	0	17
Comprehensive Income (Loss) Attributable to Parent	166	26	217	171
SOUTHERN Co GAS
Net income (loss)	106	(31)	376	248
Qualifying hedges:
Changes in fair value, net of tax	(3)	1	(3)	1
Reclassification adjustment for amounts included in net income, net of tax	0	0	0	2
Pension and other postretirement benefit plans:
Reclassification adjustment for amounts included in net income, net of tax	0	0	(1)	0
Total other comprehensive income (loss)	(3)	1	(4)	3
Comprehensive Income (Loss)	$ 103	$ (30)	$ 372	$ 251

Condensed Consolidated Statem_4

Condensed Consolidated Statements of Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Qualifying hedges:
Changes in fair value, tax	$ (11)	$ (18)	$ (21)	$ (3)
Reclassification adjustment for amounts included in net income, tax	(1)	21	8	15
Pension and other postretirement benefit plans:
Reclassification adjustment for amounts included in net income, tax	0	1	0	1
ALABAMA POWER CO
Qualifying hedges:
Reclassification adjustment for amounts included in net income, tax	0	0	1	1
GEORGIA POWER CO
Qualifying hedges:
Changes in fair value, tax	(9)	0	(9)	0
Reclassification adjustment for amounts included in net income, tax	0	0	0	1
MISSISSIPPI POWER CO
Qualifying hedges:
Changes in fair value, tax	0	0	0	(1)
Reclassification adjustment for amounts included in net income, tax	0	0	0	0
SOUTHERN POWER CO
Qualifying hedges:
Changes in fair value, tax	(1)	(19)	(10)	(3)
Reclassification adjustment for amounts included in net income, tax	(2)	20	6	12
Pension and other postretirement benefit plans:
Reclassification adjustment for amounts included in net income, tax	0	0	0	0
SOUTHERN Co GAS
Qualifying hedges:
Changes in fair value, tax	(1)	0	(1)	0
Reclassification adjustment for amounts included in net income, tax	0	0	0	1
Pension and other postretirement benefit plans:
Reclassification adjustment for amounts included in net income, tax	$ (1)	$ 0	$ (1)	$ 0

Condensed Consolidated Statem_5

Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Operating Activities:
Net income (loss)	$ 2,989	$ 809
Adjustments to reconcile net income (loss) to net cash provided from operating activities —
Depreciation and amortization, total	1,623	1,750
Deferred income taxes	274	(338)
Allowance for equity funds used during construction	(63)	(63)
Mark-to-market adjustments	31	3
Pension, postretirement, and other employee benefits	(65)	(74)
Settlement of asset retirement obligations	(143)	(97)
Stock based compensation expense	75	83
Estimated loss on Kemper IGCC	11	1,088
(Gain) loss on dispositions, net	(2,512)	35
Asset impairment	32	161
Other, net	(22)	(34)
Goodwill impairment	32
Loss on disposition	(2,506)	36
Changes in certain current assets and liabilities —
-Receivables	653	94
-Prepayments	(53)	(73)
-Natural gas for sale, net of temporary LIFO liquidation	255	295
-Other current assets	(18)	(40)
-Accounts payable	(1,045)	(406)
-Accrued taxes	938	213
-Accrued compensation	(312)	(284)
-Other current liabilities	(135)	136
Net cash provided from operating activities	2,513	3,258
Investing Activities:
Property additions	(3,484)	(3,828)
Nuclear decommissioning trust fund purchases	(405)	(571)
Nuclear decommissioning trust fund sales	400	566
Proceeds from dispositions and asset sales	5,000	500
Cost of removal, net of salvage	(197)	(128)
Change in construction payables, net	(107)	49
Investment in unconsolidated subsidiaries	(134)	(63)
Payments pursuant to LTSAs	(64)	(103)
Other investing activities	(7)	(46)
Net cash provided from (used for) investing activities	1,002	(3,624)
Financing Activities:
Increase in notes payable, net	83	1,442
Proceeds —
Long-term debt	1,390	1,100
Common stock	452	222
Short-term borrowings	250	1,650
Redemptions and repurchases —
Long-term debt	(2,560)	(3,379)
Short-term borrowings	(1,850)	(550)
Distributions to noncontrolling interests	(82)	(42)
Capital contributions from noncontrolling interests	5	1,210
Payment of common stock dividends	(1,269)	(1,194)
Other financing activities	(67)	(223)
Net cash provided from (used for) financing activities	(3,648)	236
Net Change in Cash, Cash Equivalents, and Restricted Cash	(133)	(130)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	1,519	2,147
Cash, Cash Equivalents, and Restricted Cash at End of Period	1,386	2,017
Cash paid during the period for —
Interest, net of amounts capitalized	844	927
Income taxes, net	210	4
Noncash transactions — Accrued property additions at end of period	988	1,067
ALABAMA POWER CO
Operating Activities:
Net income (loss)	520	491
Adjustments to reconcile net income (loss) to net cash provided from operating activities —
Depreciation and amortization, total	493	452
Deferred income taxes	138	48
Allowance for equity funds used during construction	(28)	(27)
Pension, postretirement, and other employee benefits	(13)	(28)
Settlement of asset retirement obligations	(43)	(19)
Other, net	(1)	(21)
Changes in certain current assets and liabilities —
-Receivables	6	(153)
-Prepayments	(59)	(57)
-Other current assets	(10)	29
-Accounts payable	(246)	(196)
-Accrued taxes	8	134
-Accrued compensation	(88)	(70)
-Other current liabilities	13	116
-Materials and supplies	5	(47)
Net cash provided from operating activities	695	652
Investing Activities:
Property additions	(833)	(997)
Nuclear decommissioning trust fund purchases	(139)	(131)
Nuclear decommissioning trust fund sales	139	131
Cost of removal, net of salvage	(48)	(34)
Change in construction payables, net	(103)	(29)
Other investing activities	(18)	(15)
Net cash provided from (used for) investing activities	(1,002)	(1,075)
Proceeds —
Senior notes	0	500
Capital contributions from parent company	1,254	488
Redemptions and repurchases —
Senior notes	(200)	0
Payment of common stock dividends	(422)	(402)
Other financing activities	(15)	(21)
Net cash provided from (used for) financing activities	617	565
Net Change in Cash, Cash Equivalents, and Restricted Cash	310	142
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	313	544
Cash, Cash Equivalents, and Restricted Cash at End of Period	623	686
Cash paid during the period for —
Interest, net of amounts capitalized	154	143
Income taxes, net	63	17
Noncash transactions — Accrued property additions at end of period	168	216
GEORGIA POWER CO
Operating Activities:
Net income (loss)	759	(44)
Adjustments to reconcile net income (loss) to net cash provided from operating activities —
Depreciation and amortization, total	583	562
Deferred income taxes	153	(256)
Pension, postretirement, and other employee benefits	(56)	(47)
Settlement of asset retirement obligations	(76)	(49)
Estimated loss on Kemper IGCC	0	1,060
Other, net	0	29
Changes in certain current assets and liabilities —
-Receivables	(43)	(103)
-Other current assets	22	25
-Accounts payable	(94)	(87)
-Accrued taxes	(139)	(89)
-Accrued compensation	(32)	(56)
-Other current liabilities	(2)	(26)
-Fossil fuel stock	(26)	38
-Prepaid income taxes	63	115
Net cash provided from operating activities	1,112	1,072
Investing Activities:
Property additions	(1,712)	(1,501)
Nuclear decommissioning trust fund purchases	(266)	(440)
Nuclear decommissioning trust fund sales	260	435
Proceeds from dispositions and asset sales	9	134
Cost of removal, net of salvage	(107)	(50)
Payments pursuant to LTSAs	(9)	(46)
Other investing activities	(4)	(11)
Change in construction payables, net of joint owner portion	(5)	86
Net cash provided from (used for) investing activities	(1,834)	(1,393)
Financing Activities:
Increase in notes payable, net	11	480
Proceeds —
Short-term borrowings	250	0
Capital contributions from parent company	46	1,502
FFB loan	835	0
Pollution control revenue bonds	513	0
Redemptions and repurchases —
Short-term borrowings	0	(150)
Senior notes	0	(1,000)
Pollution control revenue bonds	(223)	(398)
Other long-term debt	0	(100)
Payment of common stock dividends	(788)	(691)
Other financing activities	(24)	(11)
Premiums on redemption and repurchases of senior notes	0	(152)
Net cash provided from (used for) financing activities	620	(520)
Net Change in Cash, Cash Equivalents, and Restricted Cash	(102)	(841)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	112	852
Cash, Cash Equivalents, and Restricted Cash at End of Period	10	11
Cash paid during the period for —
Interest, net of amounts capitalized	179	211
Income taxes, net	(6)	64
Noncash transactions — Accrued property additions at end of period	650	669
MISSISSIPPI POWER CO
Operating Activities:
Net income (loss)	74	40
Adjustments to reconcile net income (loss) to net cash provided from operating activities —
Depreciation and amortization, total	98	86
Deferred income taxes	(16)	289
Settlement of asset retirement obligations	(17)	(15)
Estimated loss on Kemper IGCC	11	28
Other, net	1	2
Changes in certain current assets and liabilities —
-Receivables	(8)	(51)
-Other current assets	(3)	(11)
-Accounts payable	(28)	(15)
-Accrued taxes	(43)	(41)
-Accrued compensation	(15)	(14)
-Other current liabilities	6	(1)
Net cash provided from operating activities	60	297
Investing Activities:
Property additions	(95)	(74)
Change in construction payables, net	(12)	(9)
Payments pursuant to LTSAs	(11)	(13)
Other investing activities	(10)	(12)
Net cash provided from (used for) investing activities	(128)	(108)
Financing Activities:
Increase in notes payable, net	0	(4)
Proceeds —
Short-term borrowings	0	300
Senior notes	0	600
Capital contributions from parent company	7	1
Pollution control revenue bonds	43	0
Redemptions and repurchases —
Short-term borrowings	0	(200)
Other long-term debt	0	(900)
Other financing activities	(1)	(6)
Return of capital	(75)	0
Net cash provided from (used for) financing activities	(26)	(209)
Net Change in Cash, Cash Equivalents, and Restricted Cash	(94)	(20)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	293	248
Cash, Cash Equivalents, and Restricted Cash at End of Period	199	228
Cash paid during the period for —
Interest, net of amounts capitalized	36	39
Income taxes, net	23	(257)
Noncash transactions — Accrued property additions at end of period	23	23
SOUTHERN POWER CO
Operating Activities:
Net income (loss)	230	160
Adjustments to reconcile net income (loss) to net cash provided from operating activities —
Depreciation and amortization, total	251	256
Deferred income taxes	(63)	(252)
Asset impairment	0	119
Other, net	(69)	(10)
Amortization of investment tax credits	(122)	(29)
Loss on disposition	(23)	0
Changes in certain current assets and liabilities —
-Receivables	(9)	(30)
-Other current assets	4	3
-Accounts payable	(17)	(41)
-Accrued compensation	(9)	(9)
-Other current liabilities	3	(4)
-Prepaid income taxes	520	(36)
Net cash provided from operating activities	719	127
Investing Activities:
Business acquisitions	(2)	(64)
Property additions	(123)	(198)
Proceeds from dispositions and asset sales	540	0
Change in construction payables, net	(23)	2
Investment in unconsolidated subsidiaries	(116)	0
Payments pursuant to LTSAs	(31)	(32)
Other investing activities	9	15
Net cash provided from (used for) investing activities	254	(277)
Financing Activities:
Increase in notes payable, net	0	(41)
Proceeds —
Short-term borrowings	0	200
Capital contributions from parent company	6	16
Redemptions and repurchases —
Short-term borrowings	(100)	0
Senior notes	0	(350)
Other long-term debt	0	(420)
Distributions to noncontrolling interests	(82)	(42)
Capital contributions from noncontrolling interests	5	1,210
Payment of common stock dividends	(103)	(156)
Other financing activities	(5)	(15)
Return of capital	(505)	(250)
Net cash provided from (used for) financing activities	(784)	152
Net Change in Cash, Cash Equivalents, and Restricted Cash	189	2
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	181	140
Cash, Cash Equivalents, and Restricted Cash at End of Period	370	142
Cash paid during the period for —
Interest, net of amounts capitalized	106	109
Income taxes, net	(421)	109
Noncash transactions — Accrued property additions at end of period	31	33
SOUTHERN Co GAS
Operating Activities:
Net income (loss)	376	248
Adjustments to reconcile net income (loss) to net cash provided from operating activities —
Depreciation and amortization, total	238	255
Deferred income taxes	59	(12)
Mark-to-market adjustments	30	2
Other, net	(26)	(24)
Goodwill impairment	0	42
Loss on disposition	0	36
Changes in certain current assets and liabilities —
-Receivables	717	504
-Natural gas for sale, net of temporary LIFO liquidation	256	295
-Other current assets	29	41
-Accounts payable	(604)	(125)
-Accrued taxes	(54)	38
-Accrued compensation	(34)	(6)
-Other current liabilities	(56)	24
Net cash provided from operating activities	931	1,318
Investing Activities:
Property additions	(603)	(679)
Proceeds from dispositions and asset sales	32	364
Cost of removal, net of salvage	(33)	(18)
Change in construction payables, net	26	(6)
Investment in unconsolidated subsidiaries	(18)	(60)
Other investing activities	10	18
Net cash provided from (used for) investing activities	(586)	(381)
Financing Activities:
Increase in notes payable, net	(158)	(515)
Redemptions and repurchases —
Long-term debt	0	(200)
Payment of common stock dividends	(235)	(235)
Other financing activities	38	10
Net cash provided from (used for) financing activities	(355)	(940)
Net Change in Cash, Cash Equivalents, and Restricted Cash	(10)	(3)
Cash, Cash Equivalents, and Restricted Cash at Beginning of Period	70	78
Cash, Cash Equivalents, and Restricted Cash at End of Period	60	75
Cash paid during the period for —
Interest, net of amounts capitalized	125	129
Income taxes, net	96	106
Noncash transactions — Accrued property additions at end of period	$ 123	$ 129

Condensed Consolidated Statem_6

Condensed Consolidated Statements of Cash Flows (Unaudited) (Parenthetical) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Interest capitalized	$ 36	$ 35
ALABAMA POWER CO
Interest capitalized	10	10
GEORGIA POWER CO
Interest capitalized	16	12
MISSISSIPPI POWER CO
Interest received	1	0
SOUTHERN POWER CO
Interest capitalized	7	10
SOUTHERN Co GAS
Interest capitalized	$ 3	$ 3

Condensed Consolidated Balance

Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Current Assets:
Cash and cash equivalents	$ 1,383	$ 1,396
Receivables —
Customer accounts receivable	1,654	1,726
Energy marketing receivables	361	801
Unbilled revenues	583	654
Under recovered fuel clause revenues	69	115
Other accounts and notes receivable	756	813
Accumulated provision for uncollectible accounts	(50)	(50)
Materials and supplies	1,440	1,465
Fossil fuel for generation	435	405
Natural gas for sale	268	524
Prepaid expenses	543	432
Assets from risk management activities, net of collateral	107	222
Other regulatory assets	607	525
Assets held for sale	58	393
Other current assets	138	162
Total current assets	8,352	9,583
Property, Plant, and Equipment:
In service	103,428	103,706
Less: Accumulated depreciation	30,693	31,038
Plant in service, net of depreciation	72,735	72,668
Nuclear fuel, at amortized cost	871	875
Construction work in progress	7,568	7,254
Total property, plant, and equipment	81,174	80,797
Other Property and Investments:
Goodwill	5,282	5,315
Equity investments in unconsolidated subsidiaries	1,557	1,580
Other intangible assets, net of amortization	550	613
Nuclear decommissioning trusts, at fair value	1,942	1,721
Leveraged leases	813	798
Miscellaneous property and investments	505	269
Total other property and investments	10,649	10,296
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,862
Deferred charges related to income taxes	794	794
Unamortized loss on reacquired debt	313	323
Regulatory assets – asset retirement obligations	4,062	2,933
Other regulatory assets, deferred	5,835	5,375
Assets held for sale, deferred	685	5,350
Other deferred charges and assets	1,141	1,463
Total deferred charges and other assets	14,692	16,238
Total Assets	114,867	116,914
Current Liabilities:
Securities due within one year	3,148	3,198
Notes payable	1,398	2,915
Energy marketing trade payables	393	856
Accounts payable —
Accounts payable	1,978	2,580
Customer deposits	489	522
Accrued taxes —
Accrued income taxes	171	21
Other accrued taxes	501	635
Accrued interest	455	472
Accrued compensation	676	1,030
Asset retirement obligations	429	404
Other regulatory liabilities	304	376
Liabilities held for sale	36	425
Operating lease obligations	228
Other current liabilities	793	852
Total current liabilities	10,999	14,286
Long-term Debt	39,682	40,736
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	7,728	6,558
Deferred credits related to income taxes	6,386	6,460
Accumulated deferred ITCs	2,283	2,372
Employee benefit obligations	2,058	2,147
Operating lease obligations, deferred	1,702
Asset retirement obligations, deferred	9,478	8,990
Accrued environmental remediation	247	268
Other cost of removal obligations	2,283	2,297
Other regulatory liabilities, deferred	176	169
Liabilities held for sale, deferred	39	2,836
Other deferred credits and liabilities	384	465
Total deferred credits and other liabilities	32,764	32,562
Total Liabilities	83,445	87,584
Redeemable Preferred Stock of Subsidiaries	291	291
Total stockholders' equity	31,131	29,039
Total Liabilities and Stockholders' Equity	114,867	116,914
ALABAMA POWER CO
Current Assets:
Cash and cash equivalents	623	313
Receivables —
Customer accounts receivable	432	403
Unbilled revenues	173	150
Other accounts and notes receivable	55	51
Accumulated provision for uncollectible accounts	(10)	(10)
Affiliated	38	94
Materials and supplies	530	546
Fossil fuel for generation	143	141
Prepaid expenses	170	66
Other regulatory assets	204	137
Other current assets	26	18
Total current assets	2,384	1,909
Property, Plant, and Equipment:
In service	29,070	30,402
Less: Accumulated depreciation	9,397	9,988
Plant in service, net of depreciation	19,673	20,414
Nuclear fuel, at amortized cost	322	324
Construction work in progress	1,097	1,113
Total property, plant, and equipment	21,092	21,851
Other Property and Investments:
Equity investments in unconsolidated subsidiaries	64	65
Nuclear decommissioning trusts, at fair value	964	847
Miscellaneous property and investments	129	127
Total other property and investments	1,157	1,039
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	152
Deferred charges related to income taxes	240	240
Regulatory assets – asset retirement obligations	1,016	147
Other regulatory assets, deferred	1,824	1,240
Other deferred charges and assets	177	188
Deferred under recovered regulatory clause revenues	25	116
Total deferred charges and other assets	3,434	1,931
Total Assets	28,067	26,730
Current Liabilities:
Securities due within one year	1	201
Accounts payable —
Affiliated	321	364
Other	334	614
Customer deposits	98	96
Accrued taxes —
Other accrued taxes	102	44
Accrued interest	88	89
Accrued compensation	140	227
Asset retirement obligations	156	163
Operating lease obligations	48
Other current liabilities	155	161
Total current liabilities	1,395	1,959
Long-term Debt	7,926	7,923
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	3,117	2,962
Deferred credits related to income taxes	2,006	2,027
Accumulated deferred ITCs	103	106
Employee benefit obligations	309	314
Operating lease obligations, deferred	137
Asset retirement obligations, deferred	3,389	3,047
Other cost of removal obligations	464	497
Other regulatory liabilities, deferred	69	69
Other deferred credits and liabilities	32	58
Total deferred credits and other liabilities	9,626	9,080
Total Liabilities	18,947	18,962
Redeemable Preferred Stock	291	291
Total stockholders' equity	8,829	7,477
Total Liabilities and Stockholders' Equity	28,067	26,730
GEORGIA POWER CO
Current Assets:
Cash and cash equivalents	10	4
Restricted cash and cash equivalents	0	108
Receivables —
Customer accounts receivable	603	591
Unbilled revenues	267	208
Under recovered fuel clause revenues	69	115
Other accounts and notes receivable	240	80
Accumulated provision for uncollectible accounts	(2)	(2)
Affiliated	16	39
Joint owner accounts receivable	178	170
Materials and supplies	513	519
Fossil fuel for generation	257	231
Prepaid expenses	68	142
Other regulatory assets	240	199
Other current assets	58	70
Total current assets	2,517	2,474
Property, Plant, and Equipment:
In service	38,517	37,675
Less: Accumulated depreciation	12,140	12,096
Plant in service, net of depreciation	26,377	25,579
Nuclear fuel, at amortized cost	549	550
Construction work in progress	5,193	4,833
Total property, plant, and equipment	32,119	30,962
Other Property and Investments:
Equity investments in unconsolidated subsidiaries	51	51
Nuclear decommissioning trusts, at fair value	978	873
Miscellaneous property and investments	74	72
Total other property and investments	1,103	996
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	1,492
Deferred charges related to income taxes	518	517
Regulatory assets – asset retirement obligations	2,839	2,644
Other regulatory assets, deferred	2,272	2,258
Other deferred charges and assets	379	514
Total deferred charges and other assets	7,500	5,933
Total Assets	43,239	40,365
Current Liabilities:
Securities due within one year	988	617
Notes payable	555	294
Accounts payable —
Affiliated	477	575
Other	901	890
Customer deposits	282	276
Accrued taxes —
Other accrued taxes	238	377
Accrued interest	112	105
Accrued compensation	163	221
Asset retirement obligations	240	202
Other regulatory liabilities	145	169
Operating lease obligations	140
Other current liabilities	383	183
Total current liabilities	4,484	3,909
Long-term Debt	10,150	9,364
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	3,212	3,062
Deferred credits related to income taxes	3,078	3,080
Accumulated deferred ITCs	257	262
Employee benefit obligations	550	599
Operating lease obligations, deferred	1,377
Asset retirement obligations, deferred	5,643	5,627
Other deferred credits and liabilities	172	139
Total deferred credits and other liabilities	14,289	12,769
Total Liabilities	28,923	26,042
Total stockholders' equity	14,316	14,323
Total Liabilities and Stockholders' Equity	43,239	40,365
MISSISSIPPI POWER CO
Current Assets:
Cash and cash equivalents	199	293
Receivables —
Customer accounts receivable	38	34
Unbilled revenues	44	41
Other accounts and notes receivable	38	31
Affiliated	17	21
Materials and supplies	52	53
Fossil fuel for generation	23	20
Other regulatory assets	107	116
Other current assets	13	19
Total current assets	531	628
Property, Plant, and Equipment:
In service	4,800	4,900
Less: Accumulated depreciation	1,427	1,429
Plant in service, net of depreciation	3,373	3,471
Construction work in progress	113	103
Total property, plant, and equipment	3,486	3,574
Other Property and Investments:
Total other property and investments	124	24
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	7
Deferred charges related to income taxes	33	33
Regulatory assets – asset retirement obligations	207	143
Other regulatory assets, deferred	328	332
Other deferred charges and assets	20	2
Accumulated deferred income taxes	145	150
Total deferred charges and other assets	733	660
Total Assets	4,874	4,886
Current Liabilities:
Securities due within one year	300	40
Accounts payable —
Affiliated	60	60
Other	49	90
Accrued taxes —
Other accrued taxes	52	95
Accrued interest	15	15
Accrued compensation	23	38
Asset retirement obligations	27	34
Other regulatory liabilities	20	12
Operating lease obligations	2
Other current liabilities	52	28
Accrued plant closure costs	24	29
Over recovered regulatory clause liabilities	12	14
Total current liabilities	634	455
Long-term Debt	1,318	1,539
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	366	378
Deferred credits related to income taxes	362	382
Employee benefit obligations	110	115
Operating lease obligations, deferred	5
Asset retirement obligations, deferred	177	126
Other cost of removal obligations	189	185
Other regulatory liabilities, deferred	79	81
Other deferred credits and liabilities	22	16
Total deferred credits and other liabilities	1,305	1,283
Total Liabilities	3,257	3,277
Total stockholders' equity	1,617	1,609
Total Liabilities and Stockholders' Equity	4,874	4,886
SOUTHERN POWER CO
Current Assets:
Cash and cash equivalents	370	181
Receivables —
Customer accounts receivable	153	111
Other accounts and notes receivable	59	116
Affiliated	49	55
Materials and supplies	185	220
Other current assets	33	37
Prepaid income taxes	489	25
Total current assets	1,338	745
Property, Plant, and Equipment:
In service	12,862	13,271
Less: Accumulated depreciation	2,255	2,171
Plant in service, net of depreciation	10,607	11,100
Construction work in progress	419	430
Total property, plant, and equipment	11,026	11,530
Other Property and Investments:
Miscellaneous property and investments	144	0
Intangible assets, net of amortization	313	345
Total other property and investments	457	345
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	370
Assets held for sale, deferred	599	576
Other deferred charges and assets	289	373
Prepaid LTSAs	107	98
Accumulated deferred income taxes	296	1,186
Income taxes receivable, non-current	36	30
Total deferred charges and other assets	1,697	2,263
Total Assets	14,518	14,883
Current Liabilities:
Securities due within one year	899	599
Notes payable	0	100
Accounts payable —
Affiliated	72	92
Other	60	77
Accrued taxes —
Accrued income taxes	23	6
Accrued interest	23	36
Liabilities held for sale	10	15
Operating lease obligations	22
Other current liabilities	116	106
Total current liabilities	1,203	1,031
Long-term Debt	4,112	4,418
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	106	105
Accumulated deferred ITCs	1,737	1,832
Operating lease obligations, deferred	373
Other deferred credits and liabilities	169	213
Total deferred credits and other liabilities	2,385	2,150
Total Liabilities	7,700	7,599
Total stockholders' equity	6,818	7,284
Total Liabilities and Stockholders' Equity	14,518	14,883
SOUTHERN Co GAS
Current Assets:
Cash and cash equivalents	56	64
Receivables —
Customer accounts receivable	281	370
Energy marketing receivables	361	801
Unbilled revenues	63	213
Other accounts and notes receivable	100	142
Accumulated provision for uncollectible accounts	(31)	(30)
Affiliated	10	11
Natural gas for sale	268	524
Prepaid expenses	120	118
Assets from risk management activities, net of collateral	101	219
Other regulatory assets	56	73
Other current assets	44	50
Total current assets	1,429	2,555
Property, Plant, and Equipment:
In service	15,680	15,177
Less: Accumulated depreciation	4,522	4,400
Plant in service, net of depreciation	11,158	10,777
Construction work in progress	628	580
Total property, plant, and equipment	11,786	11,357
Other Property and Investments:
Goodwill	5,015	5,015
Equity investments in unconsolidated subsidiaries	1,509	1,538
Other intangible assets, net of amortization	85	101
Miscellaneous property and investments	20	20
Total other property and investments	6,629	6,674
Deferred Charges and Other Assets:
Operating lease right-of-use assets, net of amortization	95
Other regulatory assets, deferred	636	669
Other deferred charges and assets	186	193
Total deferred charges and other assets	917	862
Total Assets	20,761	21,448
Current Liabilities:
Securities due within one year	351	357
Notes payable	492	650
Energy marketing trade payables	393	856
Accounts payable —
Affiliated	38	45
Other	294	402
Customer deposits	92	133
Accrued taxes —
Accrued income taxes	17	66
Other accrued taxes	70	75
Accrued interest	57	55
Accrued compensation	64	100
Other regulatory liabilities	97	79
Operating lease obligations	15
Other current liabilities	124	130
Liabilities from risk management activities, net of collateral	22	76
Total current liabilities	2,111	3,024
Long-term Debt	5,565	5,583
Deferred Credits and Other Liabilities:
Accumulated deferred income taxes	1,088	1,016
Deferred credits related to income taxes	910	940
Employee benefit obligations	354	357
Operating lease obligations, deferred	79
Accrued environmental remediation	247	268
Other cost of removal obligations	1,598	1,585
Other deferred credits and liabilities	50	105
Total deferred credits and other liabilities	4,326	4,271
Total Liabilities	12,002	12,878
Total stockholders' equity	8,759	8,570
Total Liabilities and Stockholders' Equity	$ 20,761	$ 21,448

Condensed Consolidated Balanc_2

Condensed Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Other intangible assets, amortization	$ 253	$ 235
SOUTHERN POWER CO
Other intangible assets, amortization	60	61
SOUTHERN Co GAS
Other intangible assets, amortization	$ 161	$ 145

Consolidated Statements of Stoc

Consolidated Statements of Stockholders' Equity (Unaudited) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Treasury	Paid-In Capital	Retained Earnings (Accumulated Deficit)	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests	ALABAMA POWER CO	ALABAMA POWER COCommon Stock	ALABAMA POWER COPaid-In Capital	ALABAMA POWER CORetained Earnings (Accumulated Deficit)	ALABAMA POWER COAccumulated Other Comprehensive Income (Loss)	GEORGIA POWER CO	GEORGIA POWER COCommon Stock	GEORGIA POWER COPaid-In Capital	GEORGIA POWER CORetained Earnings (Accumulated Deficit)	GEORGIA POWER COAccumulated Other Comprehensive Income (Loss)	MISSISSIPPI POWER CO	MISSISSIPPI POWER COCommon Stock	MISSISSIPPI POWER COPaid-In Capital	MISSISSIPPI POWER CORetained Earnings (Accumulated Deficit)	MISSISSIPPI POWER COAccumulated Other Comprehensive Income (Loss)	SOUTHERN POWER CO	SOUTHERN POWER COPaid-In Capital	SOUTHERN POWER CORetained Earnings (Accumulated Deficit)	SOUTHERN POWER COAccumulated Other Comprehensive Income (Loss)	SOUTHERN POWER COTotal Common Stockholders' Equity	SOUTHERN POWER CONoncontrolling Interests	SOUTHERN Co GAS	SOUTHERN Co GASPaid-In Capital	SOUTHERN Co GASRetained Earnings (Accumulated Deficit)	SOUTHERN Co GASAccumulated Other Comprehensive Income (Loss)
Beginning balance (in shares) at Dec. 31, 2017		1,009	1						31					9					1
Beginning balance at Dec. 31, 2017	$ 25,528	$ 5,038	$ (36)	$ 10,469	$ 8,885	$ (189)	$ 1,361	$ 6,829	$ 1,222	$ 2,986	$ 2,647	$ (26)	$ 11,931	$ 398	$ 7,328	$ 4,215	$ (10)	$ 1,358	$ 38	$ 4,529	$ (3,205)	$ (4)	$ 6,498	$ 3,662	$ 1,478	$ (2)	$ 5,138	$ 1,360	$ 9,022	$ 9,214	$ (212)	$ 20
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	938				938			225			225		352			352		(7)			(7)		121		121		121		279		279
Other comprehensive income (loss)	30					30		1				1	1				1	(1)				(1)	24			24	24		2			2
Stock issued (in shares)		4
Stock issued	113	$ 16		97
Stock-based compensation	36			36
Cash dividends on common stock	(586)				(586)			(202)			(202)		(339)			(339)							(78)		(78)		(78)		(118)		(118)
Contributions from noncontrolling interests	9						9																9					9
Distributions to noncontrolling interests	(13)						(13)																(13)					(13)
Net income (loss) attributable to noncontrolling interests	(6)						(6)																(6)					(6)
Other	(24)		$ (2)	1	20	(41)	(2)	(6)				(6)	(1)		1		(2)	(1)			(1)		2		(2)	5	3	(1)	0		(4)	4
Capital contributions from parent company								488		488			1,476		1,476			2		2			1	1			1		14	14
Ending balance (in shares) at Mar. 31, 2018		1,013	1						31					9					1
Ending balance at Mar. 31, 2018	26,025	$ 5,054	$ (38)	10,603	9,257	(200)	1,349	7,335	$ 1,222	3,474	2,670	(31)	13,420	$ 398	8,805	4,228	(11)	1,351	$ 38	4,531	(3,213)	(5)	6,558	3,663	1,519	27	5,209	1,349	9,199	9,228	(55)	26
Beginning balance (in shares) at Dec. 31, 2017		1,009	1						31					9					1
Beginning balance at Dec. 31, 2017	25,528	$ 5,038	$ (36)	10,469	8,885	(189)	1,361	6,829	$ 1,222	2,986	2,647	(26)	11,931	$ 398	7,328	4,215	(10)	1,358	$ 38	4,529	(3,205)	(4)	6,498	3,662	1,478	(2)	5,138	1,360	9,022	9,214	(212)	20
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	784							484										39					143						248
Ending balance (in shares) at Jun. 30, 2018		1,015	1						31					9					1
Ending balance at Jun. 30, 2018	26,692	$ 5,066	$ (39)	10,303	8,494	(188)	3,056	7,401	$ 1,222	3,480	2,729	(30)	12,702	$ 398	8,834	3,480	(10)	1,398	$ 38	4,531	(3,166)	(5)	7,574	3,023	1,464	31	4,518	3,056	9,061	9,236	(202)	27
Beginning balance (in shares) at Mar. 31, 2018		1,013	1						31					9					1
Beginning balance at Mar. 31, 2018	26,025	$ 5,054	$ (38)	10,603	9,257	(200)	1,349	7,335	$ 1,222	3,474	2,670	(31)	13,420	$ 398	8,805	4,228	(11)	1,351	$ 38	4,531	(3,213)	(5)	6,558	3,663	1,519	27	5,209	1,349	9,199	9,228	(55)	26
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	(154)				(154)			259			259		(396)			(396)		46			46		22		22		22		(31)		(31)
Other comprehensive income (loss)	12					12		1				1	1				1						4			4	4		1			1
Stock issued (in shares)		2
Stock issued	109	$ 12		97
Stock-based compensation	12			12
Cash dividends on common stock	(607)				(607)			(200)			(200)		(352)			(352)							(78)		(78)		(78)		(117)		(117)
Contributions from noncontrolling interests	22						22																22					22
Distributions to noncontrolling interests	(29)						(29)																(29)					(29)
Net income (loss) attributable to noncontrolling interests	23						23																23					23
Other	(4)		$ (1)	(2)	(2)		1	1		1								1			1		2		1		1	1	1		1
Sale of noncontrolling interests	1,283			(407)			1,690																1,283	(407)			(407)	1,690
Capital contributions from parent company								5		5			29		29								17	17			17		8	8
Return of capital to parent company																							(250)	(250)			(250)
Ending balance (in shares) at Jun. 30, 2018		1,015	1						31					9					1
Ending balance at Jun. 30, 2018	26,692	$ 5,066	$ (39)	10,303	8,494	(188)	3,056	7,401	$ 1,222	3,480	2,729	(30)	12,702	$ 398	8,834	3,480	(10)	1,398	$ 38	4,531	(3,166)	(5)	7,574	3,023	1,464	31	4,518	3,056	9,061	9,236	(202)	27
Beginning balance (in shares) at Dec. 31, 2018		1,035	1						31					9					1
Beginning balance at Dec. 31, 2018	29,039	$ 5,164	$ (38)	11,094	8,706	(203)	4,316	7,477	$ 1,222	3,508	2,775	(28)	14,323	$ 398	10,322	3,612	(9)	1,609	$ 38	4,546	(2,971)	(4)	7,284	1,600	1,352	16	2,968	4,316	8,570	8,856	(312)	26
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	2,084				2,084			217			217		311			311		37			37		56		56		56		270		270
Other comprehensive income (loss)								1				1	1				1						(4)			(4)	(4)		(1)			(1)
Stock issued (in shares)		6
Stock issued	224	$ 28		196
Stock-based compensation	24			24
Cash dividends on common stock	(623)				(623)			(211)			(211)		(394)			(394)							(51)		(51)		(51)		(118)		(118)
Contributions from noncontrolling interests	3						3																3					3
Distributions to noncontrolling interests	(41)						(41)																(41)					(41)
Net income (loss) attributable to noncontrolling interests	(29)						(29)																(29)					(29)
Other (in shares)			0
Other	6		$ (2)	7	0		1						(1)		(1)		0						(1)	(1)	(1)		(2)	1
Capital contributions from parent company								1,236		1,236			29		29			2		2			1	1			1		17	17
Return of capital to parent company																		(38)		(38)
Ending balance (in shares) at Mar. 31, 2019		1,041	1						31					9					1
Ending balance at Mar. 31, 2019	30,687	$ 5,192	$ (40)	11,321	10,167	(203)	4,250	8,720	$ 1,222	4,744	2,781	(27)	14,269	$ 398	10,350	3,529	(8)	1,610	$ 38	4,510	(2,934)	(4)	7,218	1,600	1,356	12	2,968	4,250	8,738	8,873	(160)	25
Beginning balance (in shares) at Dec. 31, 2018		1,035	1						31					9					1
Beginning balance at Dec. 31, 2018	29,039	$ 5,164	$ (38)	11,094	8,706	(203)	4,316	7,477	$ 1,222	3,508	2,775	(28)	14,323	$ 398	10,322	3,612	(9)	1,609	$ 38	4,546	(2,971)	(4)	7,284	1,600	1,352	16	2,968	4,316	8,570	8,856	(312)	26
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	2,982							513										74					230						376
Ending balance (in shares) at Jun. 30, 2019		1,046	1						31					9					1
Ending balance at Jun. 30, 2019	31,131	$ 5,217	$ (41)	11,540	10,420	(238)	4,233	8,829	$ 1,222	4,767	2,866	(26)	14,316	$ 398	10,371	3,582	(35)	1,617	$ 38	4,480	(2,897)	(4)	6,818	1,102	1,479	4	2,585	4,233	8,759	8,908	(171)	22
Beginning balance (in shares) at Mar. 31, 2019		1,041	1						31					9					1
Beginning balance at Mar. 31, 2019	30,687	$ 5,192	$ (40)	11,321	10,167	(203)	4,250	8,720	$ 1,222	4,744	2,781	(27)	14,269	$ 398	10,350	3,529	(8)	1,610	$ 38	4,510	(2,934)	(4)	7,218	1,600	1,356	12	2,968	4,250	8,738	8,873	(160)	25
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net income (loss)	899				899			296			296		448			448		37			37		174		174		174		106		106
Other comprehensive income (loss)	(35)					(35)		1				1	(27)				(27)						(8)			(8)	(8)		(3)			(3)
Stock issued (in shares)		5
Stock issued	228	$ 25		203
Stock-based compensation	11			11
Cash dividends on common stock	(646)				(646)			(211)			(211)		(394)			(394)							(52)		(52)		(52)		(117)		(117)
Contributions from noncontrolling interests	2						2																2					2
Distributions to noncontrolling interests	(47)						(47)																(47)					(47)
Net income (loss) attributable to noncontrolling interests	$ 29						29																29					29
Other (in shares)	0
Other	$ 3		$ (1)	5	0		(1)						0		1	(1)							0		1		1	(1)
Capital contributions from parent company								23		23			20		20			8		8			7	7			7		35	35
Return of capital to parent company																							(505)	(505)			(505)
Ending balance (in shares) at Jun. 30, 2019		1,046	1						31					9					1
Ending balance at Jun. 30, 2019	$ 31,131	$ 5,217	$ (41)	$ 11,540	$ 10,420	$ (238)	$ 4,233	$ 8,829	$ 1,222	$ 4,767	$ 2,866	$ (26)	$ 14,316	$ 398	$ 10,371	$ 3,582	$ (35)	$ 1,617	$ 38	$ 4,480	$ (2,897)	$ (4)	$ 6,818	$ 1,102	$ 1,479	$ 4	$ 2,585	$ 4,233	$ 8,759	$ 8,908	$ (171)	$ 22

Consolidated Statements of St_2

Consolidated Statements of Stockholders' Equity (Unaudited) (Parenthetical) - $ / shares	3 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018
Statement of Stockholders' Equity [Abstract]
Cash dividends (in dollars per share)	$ 0.62	$ 0.60	$ 0.60	$ 0.58

Introduction

Introduction	6 Months Ended
	Jun. 30, 2019
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 as of December 31, 2018 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 June 30, 2019 and 2018 . 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, 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 results of operations, financial position, or cash flows of any registrant. Recently Adopted Accounting Standards In 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (ASU 2016-02). ASU 2016-02 requires lessees to recognize on the balance sheet a lease liability and a right-of-use asset for all leases. ASU 2016-02 also changes the recognition, measurement, and presentation of expense associated with leases and provides clarification regarding the identification of certain components of contracts that would represent a lease. The accounting required by lessors is relatively unchanged and there is no change to the accounting for existing leveraged leases. The registrants adopted the new standard effective January 1, 2019. See Note (L) for additional information and related disclosures. Goodwill and Other Intangible Assets Goodwill at June 30, 2019 and December 31, 2018 was as follows: At June 30, 2019 At December 31, 2018 (in millions) Southern Company $ 5,282 $ 5,315 Southern Company Gas: Gas distribution operations $ 4,034 $ 4,034 Gas marketing services 981 981 Southern Company Gas total $ 5,015 $ 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. A goodwill impairment charge of $32 million was recorded in the second quarter 2019 in contemplation of the July 22, 2019 sale of one of PowerSecure's business units. See Note (K) under " Southern Company " for additional information. Other intangible assets were as follows: At June 30, 2019 At December 31, 2018 Gross Carrying Amount Accumulated Amortization Other Intangible Assets, Net Gross Carrying Amount Accumulated Amortization Other (in millions) (in millions) Southern Company Other intangible assets subject to amortization: Customer relationships $ 211 $ (105 ) $ 106 $ 223 $ (94 ) $ 129 Trade names 70 (23 ) 47 70 (21 ) 49 Storage and transportation contracts 64 (58 ) 6 64 (54 ) 10 PPA fair value adjustments 371 (60 ) 311 405 (61 ) 344 Other 12 (7 ) 5 11 (5 ) 6 Total other intangible assets subject to amortization $ 728 $ (253 ) $ 475 $ 773 $ (235 ) $ 538 Other intangible assets not subject to amortization: Federal Communications Commission licenses 75 — 75 75 — 75 Total other intangible assets $ 803 $ (253 ) $ 550 $ 848 $ (235 ) $ 613 Southern Power Other intangible assets subject to amortization: PPA fair value adjustments $ 371 $ (60 ) $ 311 $ 405 $ (61 ) $ 344 Southern Company Gas Other intangible assets subject to amortization: Gas marketing services Customer relationships $ 156 $ (95 ) $ 61 $ 156 $ (84 ) $ 72 Trade names 26 (8 ) 18 26 (7 ) 19 Wholesale gas services Storage and transportation contracts 64 (58 ) 6 64 (54 ) 10 Total other intangible assets subject to amortization $ 246 $ (161 ) $ 85 $ 246 $ (145 ) $ 101 Amortization associated with other intangible assets was as follows: Three Months Ended Six Months Ended June 30, 2019 (in millions) Southern Company $ 15 $ 32 Southern Power (a) $ 4 $ 10 Southern Company Gas Gas marketing services (b) $ 6 $ 12 Wholesale gas services (a) 2 4 Southern Company Gas total $ 8 $ 16 (a) Recorded as a reduction to operating revenues. (b) Included in depreciation and amortization. Restricted Cash At December 31, 2018, Georgia Power had restricted cash related to the redemption of pollution control revenue bonds, which were redeemed in January 2019. See Note (F) under " Financing Activities " for additional information. At both June 30, 2019 and December 31, 2018 , Southern Company Gas had restricted cash held as collateral for worker's compensation, life insurance, and long-term disability insurance. The following tables provide a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed balance sheets that total to the amounts shown in the condensed statements of cash flows for the registrants that had restricted cash at June 30, 2019 and/or December 31, 2018 : Southern Company Southern Company Gas (in millions) At June 30, 2019 Cash and cash equivalents $ 1,383 $ 56 Restricted cash: Other accounts and notes receivable 4 4 Total cash, cash equivalents, and restricted cash $ 1,386 (*) $ 60 (*) Total does not add due to rounding. Southern Company Georgia Power Southern Company Gas (in millions) At December 31, 2018 Cash and cash equivalents $ 1,396 $ 4 $ 64 Cash and cash equivalents held for sale 9 — — Restricted cash: Restricted cash — 108 — Other accounts and notes receivable 114 — 6 Total cash, cash equivalents, and restricted cash $ 1,519 $ 112 $ 70 Natural Gas for Sale Southern Company Gas, with the exception of Nicor Gas, carries natural gas inventory 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. Southern Company Gas recorded adjustments of $7 million and $10 million for the three and six months ended June 30, 2019 , respectively, and no material adjustments for the comparable periods in 2018. 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. Nicor Gas had no inventory decrement at June 30, 2019 . Asset Retirement Obligations See Note 6 to the financial statements in Item 8 of the Form 10-K for additional information regarding AROs. Details of the AROs included in the condensed balance sheets of Southern Company, Alabama Power, and Mississippi Power at June 30, 2019 are shown in the following table. There were no material changes in the AROs of Georgia Power or Southern Power during the first six months of 2019. Southern Company Alabama Power Mississippi Power (in millions) Balance at December 31, 2018 $ 9,394 $ 3,210 $ 160 Liabilities incurred 6 — — Liabilities settled (142 ) (43 ) (17 ) Accretion 197 70 2 Cash flow revisions 452 308 59 Balance at June 30, 2019 $ 9,907 $ 3,545 $ 204 In June 2019, Alabama Power recorded an increase of approximately $308 million to its AROs primarily related to the CCR Rule and the related state rule based on management's completion of closure designs during the second quarter 2019 for all but two of its ash pond facilities. Mississippi Power also recorded an increase of approximately $58 million to its AROs related to the CCR Rule, primarily associated with the ash pond facility at Plant Greene County, which is jointly owned with Alabama Power. The additional estimated costs to close these ash ponds under the planned closure-in-place methodology primarily relate to cost inputs from contractor bids, internal drainage and dewatering system designs, and increases in the estimated ash volumes. The cost estimate for the remaining Alabama Power ash pond facilities will be updated within the next 12 months and the change could be material. As further analysis is performed and additional details are developed with respect to ash pond closures, the traditional electric operating companies expect to periodically update their ARO cost estimates. Additionally, the closure designs and plans in the States of Alabama and Georgia are subject to approval by environmental regulatory agencies. Absent continued recovery of ARO costs through regulated rates, Southern Company's and the traditional electric operating companies' results of operations, cash flows, and financial condition could be materially impacted. The ultimate outcome of these matters cannot be determined at this time.

Regulatory Matters

Regulatory Matters	6 Months Ended
	Jun. 30, 2019
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 of Alabama Power's, Georgia Power's, and Mississippi Power's regulatory clauses at June 30, 2019 and December 31, 2018 were as follows: Regulatory Clause Balance Sheet Line Item June 30, December 31, (in millions) Alabama Power Rate CNP Compliance Deferred under recovered regulatory clause revenues $ — $ 42 Customer accounts receivable 10 — Rate CNP PPA Deferred under recovered regulatory clause revenues 25 25 Retail Energy Cost Recovery (*) Deferred under recovered regulatory clause revenues — 109 Customer accounts receivable 8 — Natural Disaster Reserve Other regulatory liabilities, deferred 19 20 Georgia Power Fuel Cost Recovery Receivables – under recovered fuel clause revenues $ 69 $ 115 Mississippi Power Fuel Cost Recovery Over recovered regulatory clause liabilities $ 9 $ 8 (*) In accordance with an accounting order issued on February 5, 2019 by the Alabama PSC, Alabama Power utilized $75 million of the 2018 Rate RSE refund liability to reduce the Rate ECR under recovered balance. See Note 2 to the financial statements under "Alabama Power – Rate ECR" in Item 8 of the Form 10-K for additional information. Alabama Power Environmental Accounting Order On April 15, 2019, Alabama Power retired Plant Gorgas Units 8, 9, and 10 and reclassified approximately $654 million of the unrecovered asset balances to regulatory assets, which are being recovered over the units' remaining useful lives, the latest being through 2037, as established prior to the decision to retire. Additionally, approximately $700 million of net capitalized asset retirement costs were reclassified to a regulatory asset in accordance with accounting guidance provided by the Alabama PSC. The asset retirement costs are being recovered through 2055. See Note 2 to the financial statements under "Alabama Power – Environmental Accounting Order" and Note 6 in Item 8 of the Form 10-K for additional information. Georgia Power Rate Plans On June 28, 2019, Georgia Power filed a base rate case (Georgia Power 2019 Base Rate Case) with the Georgia PSC. The filing includes a three -year Alternate Rate Plan with requested rate increases totaling $563 million , $145 million , and $234 million effective January 1, 2020, January 1, 2021, and January 1, 2022, respectively. These increases are based on a proposed retail ROE of 10.90% and a proposed equity ratio of 56% and reflect levelized revenue requirements during the three -year period, with the exception of incremental compliance costs related to CCR AROs, Demand-Side Management programs, and adjustments to the Municipal Franchise Fee tariff. Georgia Power has requested recovery of the proposed increases through its existing base rate tariffs as follows: Tariff 2020 2021 2022 (in millions) Traditional base: Levelized $ 209 $ — $ — CCR AROs 158 140 227 Environmental Compliance Cost Recovery 165 — — Demand-Side Management 14 2 1 Municipal Franchise Fee 17 3 5 Total (*) $ 563 $ 145 $ 234 (*) Totals may not add due to rounding. Georgia Power's filing primarily reflects requests to (i) address the impacts of the Tax Reform Legislation, (ii) recover the costs of recent and future capital investments in infrastructure designed to maintain high levels of reliability and superior customer service with updated depreciation rates, (iii) recover substantial storm damage expenses incurred and deferred since 2013 along with a reasonable level of storm damage expenses expected to be incurred during the three years ending December 31, 2022, and (iv) recover the costs necessary to comply with federal and state regulations for CCR AROs. In addition, the filing includes the following provisions: • Continuation of an allowed retail ROE range of 10.00% to 12.00% . • Continuation of the process whereby two-thirds of any earnings above the top of the allowed ROE range are shared with Georgia Power's customers and the remaining one-third are retained by Georgia Power. • Continuation of the option to file an Interim Cost Recovery tariff in the event earnings are projected to fall below the bottom of the ROE range during the three -year term of the plan. Georgia Power expects the Georgia PSC to issue a final order in this matter on December 17, 2019. The ultimate outcome of this matter cannot be determined at this time. Integrated Resource Plan In 2016, the Georgia PSC approved Georgia Power's triennial Integrated Resource Plan, including recovery of costs up to $99 million through June 30, 2019 to preserve nuclear generation as an option at a future generation site in Stewart County, Georgia. In 2017, the Georgia PSC approved Georgia Power's decision to suspend work at the site due to changing economics, including lower load forecasts and fuel costs. In accordance with the Georgia PSC's order, costs incurred of approximately $50 million have been recorded as a regulatory asset. On July 16, 2019, the Georgia PSC voted to approve Georgia Power's triennial Integrated Resource Plan (2019 IRP) as modified by a stipulated agreement among Georgia Power, the staff of the Georgia PSC, and certain intervenors and further modified by the Georgia PSC. In the 2019 IRP, the Georgia PSC approved the decertification and retirement of Plant Hammond Units 1 through 4 ( 840 MWs) and Plant McIntosh Unit 1 ( 142.5 MWs) effective July 29, 2019. The Georgia PSC also approved the reclassification of the remaining net book values of the Plant Hammond and Plant McIntosh units (approximately $500 million and $40 million , respectively, at June 30, 2019 ), as well as any unusable materials and supplies inventory balances, upon retirement to a regulatory asset. Recovery of each unit's net book value will continue through December 31, 2019 as provided in the 2013 ARP. For the regulatory asset balances remaining at December 31, 2019, Georgia Power requested recovery in the Georgia Power 2019 Base Rate Case as follows: (i) the net book values of Plant Mitchell Unit 3 (approximately $8 million at June 30, 2019 ) and Plant McIntosh Unit 1 , any unusable materials and supplies inventory, and the future generation site in Stewart County, Georgia over a three -year period ending December 31, 2022 and (ii) the net book values of Plant Hammond Units 1 through 4 over a period equal to the applicable unit's remaining useful life through 2035. The ultimate outcome of these matters cannot be determined at this time. Also in the 2019 IRP, the Georgia PSC rejected a request to certify approximately 25 MWs of capacity at Plant Scherer Unit 3 for the retail jurisdiction beginning January 1, 2020 following the expiration of a wholesale PPA. Georgia Power may offer such capacity in the wholesale market or to the retail jurisdiction in a future Integrated Resource Plan. The ultimate outcome of this matter cannot be determined at this time but is not expected to have a material impact on Georgia Power's or Southern Company's financial statements. Additionally, the Georgia PSC approved Georgia Power's proposed environmental compliance strategy associated with ash pond and certain landfill closures and post-closure care in compliance with the CCR Rule and the related state rule. In the Georgia Power 2019 Base Rate Case, Georgia Power requested recovery of the under recovered balance of these compliance costs at December 31, 2019 (approximately $135 million at June 30, 2019 ) over a three -year period ending December 31, 2022 and recovery of estimated compliance costs of $277 million for 2020, $395 million for 2021, and $655 million for 2022 over three -year periods ending December 31, 2022, 2023, and 2024, respectively. 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. The Georgia PSC also approved Georgia Power to (i) issue requests for proposals (RFP) for capacity beginning in 2022 or 2023 and in 2026, 2027, or 2028; (ii) procure up to an additional 2,210 MWs of renewable resources through competitive RFPs; and (iii) invest in a portfolio of up to 80 MWs of battery energy storage technologies. See "Rate Plans" herein for additional information regarding the Georgia Power 2019 Base Rate Case. Nuclear Construction See Note 2 to the financial statements under "Georgia Power – Nuclear Construction" in Item 8 of the Form 10-K for additional information regarding Georgia Power's construction of Plant Vogtle Units 3 and 4, the joint ownership agreements and related funding agreement, VCM reports, and the NCCR tariff. In 2009, the Georgia PSC certified construction of Plant Vogtle Units 3 and 4. Georgia Power holds a 45.7% ownership interest in Plant Vogtle Units 3 and 4. 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 March 2017, the EPC Contractor filed for bankruptcy protection under Chapter 11 of the U.S. Bankruptcy Code. In connection with the EPC Contractor's bankruptcy filing, 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. Cost and Schedule Georgia Power's approximate proportionate share of the remaining estimated capital cost to complete Plant Vogtle Units 3 and 4 by the expected in-service dates of November 2021 and November 2022, respectively, is as follows: (in billions) Base project capital cost forecast (a)(b) $ 8.0 Construction contingency estimate 0.4 Total project capital cost forecast (a)(b) 8.4 Net investment as of June 30, 2019 (b) (5.2 ) Remaining estimate to complete (a) $ 3.2 (a) Excludes financing costs expected to be capitalized through AFUDC of approximately $315 million . (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 $3.1 billion , of which $2.0 billion had been incurred through June 30, 2019 . In April 2019, Southern Nuclear completed a cost and schedule validation process to verify and update quantities of commodities remaining to install, labor hours to install remaining quantities and related productivity, testing and system turnover requirements, and forecasted staffing needs and related costs. This process confirmed the estimated total project capital cost forecast for Plant Vogtle Units 3 and 4. The expected in-service dates of November 2021 for Unit 3 and November 2022 for Unit 4, as previously approved by the Georgia PSC, remain unchanged. As construction continues and testing and system turnover activities increase, challenges with management of contractors, subcontractors, and vendors; supervision of craft labor and related craft labor productivity, ability to attract and retain craft labor, and/or related cost escalation; procurement, fabrication, delivery, assembly, and/or installation and the initial testing and start-up, including any required engineering changes, of plant systems, structures, or components (some of which are based on new technology that only recently began initial operation in the global nuclear industry at this scale), or regional transmission upgrades, any of which may require additional labor and/or materials; or other issues could arise and change the projected schedule and estimated cost. The April 2019 cost and schedule validation process established target values for monthly construction production and system turnover activities as part of a strategy to maintain and, where possible, build margin to the approved in-service dates. To support that strategy, monthly production and activity target values will continue to increase significantly throughout 2019. To meet these increasing monthly targets, existing craft construction productivity must improve and additional craft laborers (particularly electrical and pipefitter craft labor), as well as additional supervision and other field support resources, must be retained and deployed. 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. Processes are in place that are designed to assure 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. As a result of such compliance processes, certain license amendment requests have been filed and approved or are pending before the NRC. 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, may arise, which may result in additional license amendments or require other resolution. If any license amendment requests or other licensing-based compliance issues 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 regulatory-approved project schedule is currently estimated to result in additional base capital costs of approximately $50 million per month, based on Georgia Power's ownership interests, and AFUDC of approximately $12 million per month. While Georgia Power is not precluded from seeking recovery of any future capital cost forecast increase, 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. As a result of the increase in the total project capital cost forecast and Georgia Power's decision not to seek rate recovery of the increase in the base capital costs in conjunction with the nineteenth VCM report, the holders of at least 90% of the ownership interests in Plant Vogtle Units 3 and 4 were required to vote to continue construction. In September 2018, the Vogtle Owners unanimously voted to continue construction of Plant Vogtle Units 3 and 4. Amendments to the Vogtle Joint Ownership Agreements In connection with the vote to continue construction, Georgia Power entered into (i) a binding term sheet (Vogtle Owner Term Sheet) with the other Vogtle Owners and MEAG'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 and MEAG SPVJ to provide funding with respect to MEAG SPVJ's ownership interest in Plant Vogtle Units 3 and 4 under certain circumstances. On January 14, 2019, Georgia Power, MEAG, and MEAG SPVJ entered into an agreement to implement the provisions of the MEAG Term Sheet. On February 18, 2019, Georgia Power, the other Vogtle Owners, and MEAG'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. 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 June 30, 2019 , Georgia Power had recovered approximately $2.0 billion of financing costs. Financing costs related to capital costs above $4.418 billion will be recovered through AFUDC; however, Georgia Power will not record 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 December 2018, the Georgia PSC approved Georgia Power's request to increase the NCCR tariff by $88 million annually, effective January 1, 2019. 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 amounts 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 prudence decisions on cost recovery will be made at a later date, 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 ARP) 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 upon Unit 3 reaching commercial operation, retail base rates would be adjusted to include carrying costs on those capital costs deemed prudent in the Vogtle Cost Settlement Agreement. 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 $100 million in 2018 and are estimated to have negative earnings impacts of approximately $70 million in 2019 and an aggregate of approximately $630 million from 2020 to 2022. 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 February 2018, Georgia Interfaith Power & Light, Inc. (GIPL) and Partnership for Southern Equity, Inc. (PSE) filed a petition appealing the Georgia PSC's January 11, 2018 order with the Fulton County Superior Court. In March 2018, Georgia Watch filed a similar appeal to the Fulton County Superior Court for judicial review of the Georgia PSC's decision and denial of Georgia Watch's motion for reconsideration. In December 2018, the Fulton County Superior Court granted Georgia Power's motion to dismiss the two appeals. On January 9, 2019, GIPL, PSE, and Georgia Watch filed an appeal of this decision with the Georgia Court of Appeals. Georgia Power believes the appeal has no merit; however, an adverse outcome in the appeal combined with subsequent adverse action by the Georgia PSC could have a material impact on Southern Company's and Georgia Power's results of operations, financial condition, and liquidity. In August 2018, Georgia Power filed its nineteenth VCM report with the Georgia PSC, which requested approval of $578 million of construction capital costs incurred from January 1, 2018 through June 30, 2018. On February 19, 2019, the Georgia PSC approved the nineteenth VCM, but deferred approval of $51.6 million of expenditures related to Georgia Power's portion of an administrative claim filed in the Westinghouse bankruptcy proceedings. Through the nineteenth VCM, the Georgia PSC has approved total construction capital costs incurred through June 30, 2018 of $5.4 billion (before $1.7 billion of payments received under the Guarantee Settlement Agreement and approximately $188 million in related Customer Refunds). On April 30, 2019, as requested by the staff of the Georgia PSC, Georgia Power reported the results of the cost and schedule validation process to the Georgia PSC. On August 30, 2019, Georgia Power will file its twentieth VCM report concurrently with its twenty-first VCM report with the Georgia PSC, which will reflect the capital cost forecast discussed previously and request approval of $1.2 billion of construction capital costs incurred from June 30, 2018 through June 30, 2019. In addition, on June 20, 2019, Georgia Power, acting for itself and as agent for the other Vogtle Owners, entered into a settlement agreement related to the administrative claim filed in the Westinghouse bankruptcy proceedings. Accordingly, in the twentieth/twenty-first VCM report, Georgia Power will also request approval of the $51.6 million of associated expenditures previously deferred by the Georgia PSC. The ultimate outcome of these matters cannot be determined at this time. DOE Financing At June 30, 2019 , Georgia Power had borrowed $3.46 billion related to Plant Vogtle Units 3 and 4 costs as provided through the Amended and Restated Loan Guarantee Agreement and related multi-advance credit facilities among Georgia Power, the DOE, and the FFB, which provide for borrowings of up to approximately $5.130 billion , subject to the satisfaction of certain conditions. See Note 8 to the financial statements under "Long-term Debt – DOE Loan Guarantee Borrowings" in Item 8 of the Form 10-K and Note (F) under " DOE Loan Guarantee Borrowings " for additional information, including applicable covenants, events of default, mandatory prepayment events, and conditions to borrowing. The ultimate outcome of these matters cannot be determined at this time. Mississippi Power Municipal and Rural Association Tariff On May 7, 2019, the FERC accepted Mississippi Power's March 28, 2019 request for a decrease in wholesale base revenues under the MRA tariff as agreed upon in a settlement agreement reached with its wholesale customers resolving all matters related to the Kemper County energy facility similar to the retail rate settlement agreement approved by the Mississippi PSC in February 2018 and reflecting the impacts of the Tax Reform Legislation. Pursuant to the MRA settlement agreement, base rates decreased $3.7 million annually, effective January 1, 2019. Environmental Compliance Overview Plan On July 9, 2019, Mississippi Power filed a request with the Mississippi PSC for a Certificate of Public Convenience and Necessity to complete certain environmental compliance projects, primarily associated with the Plant Daniel coal units co-owned 50% with Gulf Power. The total estimated cost is approximately $125 million , with Mississippi Power's share of approximately $66 million being proposed for recovery through its ECO Plan. Approximately $17 million of Mississippi Power's share is associated with ash pond closure and is reflected in Mississippi Power's ARO liabilities. See Note 2 to the financial statements under "Mississippi Power – Environmental Compliance Overview Plan" in Item 8 of the Form 10-K for additional information on Mississippi Power's ECO Plan. See Note (A) under "Asset Retirement Obligations" for additional information on AROs and Note (C) under "Other Matters – Mississippi Power" herein for additional information on Gulf Power's ownership in Plant Daniel. Kemper County Energy Facility As the mining permit holder, Liberty Fuels Company, LLC has a legal obligation to perform mine reclamation, and Mississippi Power has a contractual obligation to fund all reclamation activities. As a result of the abandonment of the Kemper IGCC, final mine reclamation began in 2018 and is expected to be substantially completed in 2020, with monitoring expected to continue through 2027. See Note 6 to the financial statements in Item 8 of the Form 10-K for additional information. During the second quarter and year-to-date 2019, Mississippi Power recorded pre-tax charges to income of $4 million ( $3 million after tax) and $6 million ( $5 million after tax), respectively, primarily resulting from the abandonment and related closure activities and ongoing period costs, net of sales proceeds, for the mine and gasifier-related assets at the Kemper County energy facility. Additional closure costs for the mine and gasifier-related assets, currently estimated at up to $10 million pre-tax (excluding dismantlement costs, net of salvage), may be incurred through the first half of 2020. In addition, period costs, including, but not limited to, costs for compliance and safety, ARO accretion, and property taxes for the mine and gasifier-related assets, are estimated at $7 million for the remainder of 2019 and $2 million to $6 million annually in 2020 through 2023. In addition, Mississippi Power constructed the CO 2 pipeline for the planned transport of captured CO 2 for use in enhanced oil recovery and is currently evaluating its options regarding the final disposition of the CO 2 pipeline, including removal of the pipeline. This evaluation is expected to be complete later in 2019. If Mississippi Power ultimately decides to remove the CO 2 pipeline, the cost of removal would have a material impact on Mississippi Power's financial statements and could have a material impact on Southern Company's financial statements. In December 2018, Mississippi Power filed with the DOE its request for property closeout certification under the contract related to the $387 million of grants received. Mississippi Power and the DOE are currently in discussions regarding the requested closeout and property disposition, which may require payment to the DOE for a portion of certain property that is to be retained by Mississippi Power. In connection with the DOE closeout discussions, on April 29, 2019, the Civil Division of the Department of Justice informed Southern Company and Mississippi Power of an investigation related to the Kemper County energy facility. The ultimate outcome of these matters cannot be determined at this time; however, they could have a material impact on Mississippi Power's and Southern Company's financial statements. Southern Company Gas Rate Proceedings Nicor Gas In November 2018, Nicor Gas filed a general base rate case with the Illinois Commission requesting a $230 million increase in annual base rate revenues. The requested increase is based on a projected test year for the 12 -month period ending September 30, 2020, a ROE of 10.6% , and an increase in the equity ratio from 52% to 54% to address the negative cash flow and credit metric impacts of the Tax Reform Legislation. On April 16, 2019, Nicor Gas entered into a stipulation agreement to resolve all related issues with the Staff of the Illinois Commission, including a ROE of 9.86% and an equity ratio of 54% . Also on April 16, 2019, Nicor Gas filed its rebuttal testimony with the Illinois Commission incorporating the stipulation agreement and addressing the remaining items outstanding with the other two intervenors. As a res

Contingencies

Contingencies	6 Months Ended
	Jun. 30, 2019
Commitments and Contingencies Disclosure [Abstract]
CONTINGENCIES	CONTINGENCIES See 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 Each registrant is subject to certain claims and legal actions arising in the ordinary course of business. In addition, the business activities of Southern Company's subsidiaries are subject to extensive governmental regulation related to public health and the environment, such as laws and regulations governing air, water, land, and protection of natural resources. Litigation over environmental issues and claims of various types, including property damage, personal injury, common law nuisance, and citizen enforcement of environmental laws and regulations, has occurred throughout the U.S. This litigation has included claims for damages alleged to have been caused by CO 2 and other emissions, CCR, and alleged exposure to hazardous materials, and/or requests for injunctive relief in connection with such matters. The ultimate outcome of such pending or potential litigation 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. Southern Company In January 2017, a putative securities class action complaint was filed against Southern Company, certain of its officers, and certain former Mississippi Power officers in the U.S. District Court for the Northern District of Georgia by Monroe County Employees' Retirement System on behalf of all persons who purchased shares of Southern Company's common stock between April 25, 2012 and October 29, 2013. The complaint alleges that Southern Company, certain of its officers, and certain former Mississippi Power officers made materially false and misleading statements regarding the Kemper County energy facility in violation of certain provisions under the Securities Exchange Act of 1934, as amended. The complaint seeks, among other things, compensatory damages and litigation costs and attorneys' fees. In 2017, the plaintiffs filed an amended complaint that provided additional detail about their claims, increased the purported class period by one day, and added certain other former Mississippi Power officers as defendants. Also in 2017, the defendants filed a motion to dismiss the plaintiffs' amended complaint with prejudice, to which the plaintiffs filed an opposition. In March 2018, the court issued an order granting, in part, the defendants' motion to dismiss. The court dismissed certain claims against certain officers of Southern Company and Mississippi Power and dismissed the allegations related to a number of the statements that plaintiffs challenged as being false or misleading. In April 2018, the defendants filed a motion for reconsideration of the court's order, seeking dismissal of the remaining claims in the lawsuit. In August 2018, the court denied the motion for reconsideration and denied a motion to certify the issue for interlocutory appeal. 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 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. Each plaintiff seeks 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. Each plaintiff also seeks certain changes to Southern Company's corporate governance and internal processes. In April 2018, the court entered an order staying this lawsuit until 30 days after the resolution of any dispositive motions or any settlement, whichever is earlier, in the putative securities class action. 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 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. The plaintiff seeks to recover, on behalf of Southern Company, unspecified actual damages and disgorgement of profits and, on its behalf, attorneys' fees and costs in bringing the lawsuit. The plaintiff also seeks certain unspecified changes to Southern Company's corporate governance and internal processes. In May 2018, the court entered an order staying this lawsuit until 30 days after the resolution of any dispositive motions or any settlement, whichever is earlier, in the putative securities class action. Southern Company believes these legal challenges have no merit; however, an adverse outcome in any of these proceedings could have an impact on Southern Company's results of operations, financial condition, and liquidity. The ultimate outcome of these matters cannot be determined at this time. 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 tort law claims. In 2016, the Georgia Court of Appeals reversed the trial court's previous dismissal of the case and remanded the case to the trial court. Georgia Power filed a petition for writ of certiorari with the Georgia Supreme Court, which was granted in 2017. In June 2018, the Georgia Supreme Court affirmed the judgment of the Georgia Court of Appeals and remanded the case to the trial court for further proceedings. Following a motion by Georgia Power, on February 13, 2019, the Superior Court of Fulton County ordered the parties to submit petitions to the Georgia PSC for a declaratory ruling to address certain terms the court previously held were ambiguous as used in the Georgia PSC's orders. The order entered by the Superior Court of Fulton County also conditionally certified the proposed class. In March 2019, Georgia Power and the plaintiffs filed petitions with the Georgia PSC seeking confirmation of the proper application of the municipal franchise fee schedule pursuant to the Georgia PSC's orders. Georgia Power also filed a notice of appeal with the Georgia Court of Appeals regarding the Superior Court of Fulton County's February 2019 order. Georgia Power believes the plaintiffs' claims have no merit. The amount of any possible losses cannot be calculated at this time because, among other factors, it is unknown whether conditional class certification will be upheld and the ultimate composition of any class and whether any losses would be subject to recovery from any municipalities. The ultimate outcome of this matter cannot be determined at this time. Mississippi Power In May 2018, Southern Company and Mississippi Power received a notice of dispute and arbitration demand filed by Martin Product Sales, LLC (Martin) based on two agreements, both related to Kemper IGCC byproducts for which Mississippi Power provided termination notices in 2017. Martin alleges breach of contract, breach of good faith and fair dealing, fraud and misrepresentation, and civil conspiracy and makes a claim for damages in the amount of approximately $143 million , as well as additional unspecified damages, attorney's fees, costs, and interest. In the first quarter 2019, Mississippi Power and Southern Company filed motions to dismiss, which were denied by the arbitration panel on May 10, 2019. Southern Company and Mississippi Power believe this legal challenge has no merit; however, an adverse outcome in this proceeding could have a material impact on Southern Company's and Mississippi Power's results of operations, financial condition, and liquidity. The ultimate outcome of this matter cannot be determined at this time. In November 2018, Ray C. Turnage and 10 other individual plaintiffs filed a putative class action complaint against Mississippi Power and the three current members of the Mississippi PSC in the U.S. District Court for the Southern District of Mississippi. 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. 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. In response to Mississippi Power and the Mississippi PSC each filing a motion to dismiss, the plaintiffs filed an amended complaint on March 14, 2019. The amended complaint included four additional plaintiffs and additional claims for gross negligence, reckless conduct, and intentional wrongdoing. Mississippi Power and the Mississippi PSC have each filed a motion to dismiss the amended complaint. Mississippi Power believes this legal challenge has no merit; however, an adverse outcome in this proceeding could have a material impact on Mississippi Power's results of operations, financial condition, and liquidity. The ultimate outcome of this matter cannot be determined at this time. Southern Power Southern Power indirectly owns a 51% membership interest in RE Roserock LLC (Roserock), the owner of the Roserock facility in Pecos County, Texas. Prior to the facility being placed in service in 2016, certain solar panels were damaged during installation by the construction contractor, McCarthy Building Companies, Inc. (McCarthy), and certain solar panels were damaged by a hail event that also occurred during construction. In connection therewith, Southern Power withheld payment of approximately $26 million to the construction contractor, which placed a lien on the Roserock facility for the same amount. In 2017, Roserock filed a lawsuit in the state district court in Pecos County, Texas against XL Insurance America, Inc. and North American Elite Insurance Company seeking recovery from an insurance policy for damages resulting from the hail event and McCarthy's installation practices. In June 2018, the court granted Roserock's motion for partial summary judgment, finding that the insurers were in breach of contract and in violation of the Texas Insurance Code for failing to pay any monies owed for the hail claim. Separate lawsuits were filed between Roserock and McCarthy, as well as other parties, and that litigation was consolidated in the U.S. District Court for the Western District of Texas. On April 18, 2019, Roserock and the parties to the state and federal lawsuits executed a settlement agreement and mutual release that resolved both lawsuits. Following execution of the agreement, the lawsuits were dismissed, Southern Power paid McCarthy the amounts previously withheld, and McCarthy released its lien. As part of the settlement, Roserock received funds that covered all related legal costs, damages, and the replacement costs of certain solar panels. Funds received by Southern Power in excess of the initial replacement costs were recognized as a gain and included in other income (expense), net in 2019. A portion of the pre-tax gain was allocated to noncontrolling interests and Southern Power recognized a $12 million after-tax gain. 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 compliance 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 $18 million and $23 million as of June 30, 2019 and December 31, 2018 , 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 $283 million and $294 million as of June 30, 2019 and December 31, 2018 , respectively, based on the estimated cost of environmental investigation and remediation associated with known current and former manufactured gas plant operating sites. These environmental remediation expenditures are recoverable from customers through rate mechanisms approved by the applicable state regulatory agencies of the natural gas distribution utilities, with the exception of one site representing $2 million of the total accrued remediation costs. 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 Southern Company, Georgia Power, or Southern Company Gas. Nuclear Fuel Disposal Costs In 2014, Alabama Power and Georgia Power filed lawsuits against the U.S. government for the costs of continuing to store spent nuclear fuel at Plants Farley, Hatch, and Vogtle Units 1 and 2 for the period from January 1, 2011 through December 31, 2013. The damage period was subsequently extended to December 31, 2014. On June 12, 2019, the Court of Federal Claims granted Alabama Power's and Georgia Power's motion for summary judgment on damages not disputed by the U.S. government, awarding those undisputed damages to Alabama Power and Georgia Power. However, those undisputed damages are not collectible and no amounts will be recognized in the financial statements until the court enters final judgment on the remaining damages. The final outcome of these matters cannot be determined at this time. However, Alabama Power and Georgia Power expect to credit any recoveries for the benefit of customers in accordance with direction from their respective PSC; therefore, no material impact on Southern Company's, Alabama Power's, or Georgia Power's net income is expected. Other Matters Alabama Power On May 17, 2019, the Alabama Department of Environmental Management (ADEM) issued a proposed administrative order assessing a penalty of $250,000 to Alabama Power for unpermitted discharge of fluids and/or pollutants to groundwater and/or soils at Plant Gadsden. The proposed order also requires the submission to the ADEM of a plan with a schedule for implementation of a comprehensive groundwater investigation, an assessment of corrective measures, a report evaluating any deficiencies at the facility that may have led to the unpermitted discharge, and quarterly progress reports. Alabama Power is awaiting finalization of the order and the ultimate outcome of this matter cannot be determined at this time; however, it is not expected to have a material impact on Alabama Power's net income. Mississippi Power In conjunction with Southern Company's sale of Gulf Power, Mississippi Power and Gulf Power have committed to seek a restructuring of their 50% undivided ownership interests in Plant Daniel such that each of them would, after the restructuring, own 100% of a generating unit. On January 15, 2019, Gulf Power provided notice to Mississippi Power that Gulf Power will retire its share of the generating capacity of Plant Daniel on January 15, 2024. Mississippi Power has the option to purchase Gulf Power's ownership interest for $1 on January 15, 2024, provided that Mississippi Power exercises the option no later than 120 days prior to that date. Mississippi Power is assessing the potential operational and economic effects of Gulf Power's notice. The ultimate outcome of these matters remains subject to completion of Mississippi Power's evaluations and applicable regulatory approvals, including by the FERC and the Mississippi PSC, and cannot be determined at this time. See Note (K) under " Southern Company " for information regarding the sale of Gulf Power. Southern Company Gas The future performance of Southern Company Gas' natural gas storage facility consisting of two salt dome caverns in Louisiana, as well as Southern Company Gas' two other natural gas storage facilities located in California and Texas, could be impacted by ongoing changes in the U.S. natural gas storage market. Recent sales of natural gas storage facilities have resulted in losses for the sellers and may imply an impact on future rates and/or asset values. Southern Company Gas is evaluating these recent market transactions for impacts on its plans to return one of the salt dome caverns in Louisiana back to service in 2021. Sustained diminished natural gas storage values could trigger impairment of one or all of these natural gas storage facilities, which have a combined net book value of $438 million at June 30, 2019. The ultimate outcome of these matters cannot be determined at this time, but could have a material impact on Southern Company's and Southern Company Gas' financial statements.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
REVENUE FROM CONTRACTS WITH CUSTOMERS	REVENUE FROM CONTRACTS WITH CUSTOMERS The registrants generate revenues from a variety of sources, some of which are excluded from the scope of ASC 606, Revenue from Contracts with Customers (ASC 606), such as leases, derivatives, and certain cost recovery mechanisms. See Note 1 to the financial statements under "Recently Adopted Accounting Standards – Revenue" in Item 8 of the Form 10-K for additional information on the adoption of ASC 606 for revenue from contracts with customers and Note 1 to the financial statements under "Revenues" and "Other Taxes" in Item 8 of the Form 10-K for additional information on the revenue policies of the registrants. For additional information on revenues accounted for under other accounting guidance, see Notes (J) and (L) for energy-related derivative contracts and lessor revenues, respectively, Note 1 to the financial statements under "Revenues – Southern Company Gas" in Item 8 of the Form 10-K for alternative revenue programs at the natural gas distribution utilities, and Note 2 to the financial statements in Item 8 of the Form 10-K for cost recovery mechanisms. The following tables disaggregate revenue sources for the three and six months ended June 30, 2019 and 2018 : For the Three Months Ended June 30, 2019 For the Three Months Ended June 30, 2018 For the Six Months Ended June 30, 2019 For the Six Months Ended June 30, 2018 (in millions) Southern Company Operating revenues Retail electric revenues (a) Residential $ 1,488 $ 1,579 $ 2,776 $ 3,118 Commercial 1,258 1,315 2,350 2,557 Industrial 763 814 1,440 1,569 Other 31 32 57 64 Natural gas distribution revenues (b) 562 642 1,724 1,865 Alternative revenue programs (c) 1 (4 ) — (27 ) Total retail electric and gas distribution revenues $ 4,103 $ 4,378 $ 8,347 $ 9,146 Wholesale energy revenues (d)(e) 410 464 777 937 Wholesale capacity revenues (e) 132 152 264 302 Other natural gas revenues (f)(g) 126 68 439 476 Other revenues (h) 327 565 683 1,138 Total operating revenues $ 5,098 $ 5,627 $ 10,510 $ 11,999 (a) Retail electric revenues include $8 million , $18 million , $16 million , and $36 million of revenues accounted for as leases for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, and a (net reduction) or net increase of $(14) million , $68 million , $(117) million and $101 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, from certain cost recovery mechanisms that are not accounted for as revenue under ASC 606. (b) Natural gas distribution revenues include $5 million for each of the three months ended June 30, 2019 and 2018 and $8 million for each of the six months ended June 30, 2019 and 2018 of revenues not accounted for under ASC 606. (c) Alternative revenue program revenues are presented net of any previously recognized program amounts billed to customers during the same accounting period. (d) Wholesale energy revenues include $30 million , $61 million , $82 million , and $155 million of revenues accounted for as derivatives for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, primarily related to physical energy sales in the wholesale electricity market. (e) Wholesale energy revenues include $115 million , $118 million , $182 million , and $187 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, and wholesale capacity revenues include $22 million , $31 million , $47 million , and $61 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, related to PPAs accounted for as leases. (f) Other natural gas revenues related to Southern Company Gas' energy and risk management activities are presented net of the related costs of those activities and include gross third-party revenues of $1.2 billion , $1.3 billion , $3.1 billion , and $3.3 billion for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, of which $0.8 billion , $0.7 billion , $2.0 billion , and $1.8 billion , respectively, relates to contracts that are accounted for as derivatives. See Note (M) under " Southern Company Gas " for additional information on the components of wholesale gas services operating revenues. (g) Other natural gas revenues include $10 million and $27 million for the three and six months ended June 30, 2019 , respectively, of revenues not accounted for under ASC 606, including $8 million and $16 million , respectively, of revenues accounted for as leases. (h) Other revenues include $89 million , $89 million , $180 million , and $183 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, of revenues not accounted for under ASC 606, including $28 million , $33 million , $59 million , and $66 million , respectively, accounted for as leases. Alabama Power Georgia Power Mississippi Power (in millions) For the Three Months Ended June 30, 2019 Operating revenues Retail revenues (a)(b) Residential $ 588 $ 831 $ 69 Commercial 418 767 73 Industrial 366 327 70 Other 6 21 3 Total retail electric revenues $ 1,378 $ 1,946 $ 215 Wholesale energy revenues (c) 41 14 93 Wholesale capacity revenues 25 22 1 Other revenues (b)(d) 69 135 4 Total operating revenues $ 1,513 $ 2,117 $ 313 For the Three Months Ended June 30, 2018 Operating revenues Retail revenues (a)(b) Residential $ 557 $ 785 $ 65 Commercial 402 749 68 Industrial 372 335 76 Other 7 20 3 Total retail electric revenues $ 1,338 $ 1,889 $ 212 Wholesale energy revenues (c) 71 26 77 Wholesale capacity revenues 25 13 1 Other revenues (b)(d) 69 120 7 Total operating revenues $ 1,503 $ 2,048 $ 297 (a) Retail revenues at Alabama Power, Georgia Power, and Mississippi Power include a net increase or (net reduction) of $(11) million , $(5) million , and $2 million , respectively, for the three months ended June 30, 2019 and $78 million , $3 million , and $(1) million , respectively, for the three months ended June 30, 2018 related to certain cost recovery mechanisms that are not accounted for as revenue under ASC 606. (b) Retail revenues and other revenues at Georgia Power include $8 million and $11 million , respectively, for the three months ended June 30, 2019 and $18 million and $33 million , respectively, for the three months ended June 30, 2018 of revenues accounted for as leases. (c) Wholesale energy revenues at Alabama Power, Georgia Power, and Mississippi Power include $3 million , $4 million , and $1 million , respectively, for the three months ended June 30, 2019 and $4 million , $5 million , and $1 million , respectively, for the three months ended June 30, 2018 accounted for as derivatives primarily related to physical energy sales in the wholesale electricity market. (d) Other revenues at Alabama Power and Georgia Power include $31 million and $30 million , respectively, for the three months ended June 30, 2019 and $26 million and $26 million , respectively, for the three months ended June 30, 2018 of revenues not accounted for under ASC 606. Alabama Power Georgia Power Mississippi Power (in millions) For the Six Months Ended June 30, 2019 Operating revenues Retail revenues (a)(b) Residential $ 1,128 $ 1,519 $ 129 Commercial 772 1,440 138 Industrial 679 616 145 Other 13 39 6 Total retail electric revenues $ 2,592 $ 3,614 $ 418 Wholesale energy revenues (c) 135 27 170 Wholesale capacity revenues 51 40 2 Other revenues (b)(d) 143 270 10 Total operating revenues $ 2,921 $ 3,951 $ 600 For the Six Months Ended June 30, 2018 Operating revenues Retail revenues (a)(b) Residential $ 1,127 $ 1,529 $ 125 Commercial 774 1,466 130 Industrial 710 650 146 Other 13 43 5 Total retail electric revenues $ 2,624 $ 3,688 $ 406 Wholesale energy revenues (c) 172 66 176 Wholesale capacity revenues 49 27 5 Other revenues (b)(d) 131 227 11 Total operating revenues $ 2,976 $ 4,008 $ 598 (a) Retail revenues at Alabama Power, Georgia Power, and Mississippi Power include a net increase or (net reduction) of $(68) million , $(52) million , and $3 million , respectively, for the six months ended June 30, 2019 and $125 million , $12 million , and $(8) million , respectively, for the six months ended June 30, 2018 related to certain cost recovery mechanisms that are not accounted for as revenue under ASC 606. (b) Retail revenues and other revenues at Georgia Power include $16 million and $23 million , respectively, for the six months ended June 30, 2019 and $36 million and $66 million , respectively, for the six months ended June 30, 2018 of revenues accounted for as leases. (c) Wholesale energy revenues at Alabama Power, Georgia Power, and Mississippi Power include $6 million , $8 million , and $1 million , respectively, for the six months ended June 30, 2019 and $9 million , $13 million , and $2 million , respectively, for the six months ended June 30, 2018 accounted for as derivatives primarily related to physical energy sales in the wholesale electricity market. (d) Other revenues at Alabama Power and Georgia Power include $59 million and $61 million , respectively, for the six months ended June 30, 2019 and $52 million and $53 million , respectively, for the six months ended June 30, 2018 of revenues not accounted for under ASC 606. For the Three Months Ended June 30, 2019 For the Three Months Ended June 30, 2018 For the Six Months Ended June 30, 2019 For the Six Months Ended June 30, 2018 (in millions) Southern Power PPA capacity revenues (a) $ 125 $ 144 $ 252 $ 282 PPA energy revenues (a) 291 302 518 556 Non-PPA revenues (b) 91 106 177 221 Other revenues 3 3 6 5 Total operating revenues $ 510 $ 555 $ 953 $ 1,064 (a) PPA capacity revenues include $39 million , $47 million , $80 million , and $94 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, and PPA energy revenues include $125 million , $127 million , $198 million , and $203 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, related to PPAs accounted for as leases. (b) Non-PPA revenues include $22 million , $50 million , $67 million , and $129 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, of revenues from short-term sales related to physical energy sales from uncovered capacity in the wholesale electricity market. For the Three Months Ended June 30, 2019 For the Three Months Ended June 30, 2018 For the Six Months Ended June 30, 2019 For the Six Months Ended June 30, 2018 (in millions) Southern Company Gas Operating revenues Natural gas distribution revenues (a) Residential $ 229 $ 273 $ 830 $ 933 Commercial 65 76 235 268 Transportation 213 228 469 505 Industrial 5 7 22 24 Other 50 58 168 135 Alternative revenue programs (b) 1 (4 ) — (27 ) Total natural gas distribution revenues $ 563 $ 638 $ 1,724 $ 1,838 Gas pipeline investments (c) 8 8 16 16 Wholesale gas services (d) 48 (15 ) 114 131 Gas marketing services (e) 58 89 287 359 Other revenues 12 10 22 25 Total operating revenues $ 689 $ 730 $ 2,163 $ 2,369 (a) Natural gas distribution revenues include $5 million for each of the three months ended June 30, 2019 and 2018 and $8 million for each of the six months ended June 30, 2019 and 2018 of revenues not accounted for under ASC 606. (b) Alternative revenue program revenues are presented net of any previously recognized program amounts billed to customers during the same accounting period. (c) Revenues from gas pipeline investments include $8 million and $16 million for the three and six months ended June 30, 2019 , respectively, accounted for as leases. (d) Wholesale gas services revenues are presented net of the related costs associated with its energy trading and risk management activities. Operating revenues, as presented, include gross third-party revenues of $1.2 billion , $1.3 billion , $3.1 billion , and $3.3 billion for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, of which $0.8 billion , $0.7 billion , $2.0 billion , and $1.8 billion , respectively, relates to contracts accounted for as derivatives. See Note (M) under " Southern Company Gas " for additional information on the components of wholesale gas services operating revenues. (e) Gas marketing services include $2 million for the three months ended June 30, 2019 and $11 million and $4 million for the six months ended June 30, 2019 and 2018 , respectively, of revenues not accounted for under ASC 606. Contract Balances The following table reflects the closing balances of receivables, contract assets, and contract liabilities related to revenues from contracts with customers as of June 30, 2019 and December 31, 2018 : Receivables Contract Assets Contract Liabilities June 30, 2019 December 31, 2018 June 30, 2019 December 31, 2018 June 30, 2019 December 31, 2018 (in millions) Southern Company (*) $ 2,343 $ 2,630 $ 70 $ 102 $ 58 $ 32 Alabama Power 629 520 — — 10 12 Georgia Power 807 721 30 58 26 7 Mississippi Power 93 100 — — 7 — Southern Power 119 118 — — 1 11 Southern Company Gas 550 952 — — 1 2 (*) Includes amounts related to held for sale investments. As of June 30, 2019 and December 31, 2018 , Georgia Power had contract assets primarily related to unregulated service agreements where payment is contingent on project completion and fixed retail customer bill programs where the payment is contingent upon Georgia Power's continued performance and the customer's continued participation in the program over the one-year contract term. Alabama Power had contract liabilities for outstanding performance obligations primarily related to extended service agreements. Contract liabilities for Georgia Power and Southern Power relate to cash collections recognized in advance of revenue for certain unregulated service agreements and certain levelized PPAs, respectively. Mississippi Power had contract liabilities for cash collections recognized in advance of revenue for operating agreements associated with a tolling arrangement accounted for as a sales-type lease. Southern Company's unregulated distributed generation business had $32 million and $39 million of contract assets and $14 million and $11 million of contract liabilities at June 30, 2019 and December 31, 2018 , respectively, remaining for outstanding performance obligations. The following table reflects revenue from contracts with customers recognized in the three and six months ended June 30, 2019 included in the contract liability at December 31, 2018 : Three Months Ended Six Months Ended (in millions) Southern Company $ 11 $ 27 Southern Power 1 11 Revenues recognized in the three and six months ended June 30, 2019 , which were included in contract liabilities at December 31, 2018 , were immaterial for Alabama Power, Georgia Power, and Southern Company Gas. Remaining Performance Obligations The traditional electric operating companies and Southern Power have long-term contracts with customers in which revenues are recognized when the performance obligations are satisfied during the contract term. These contracts primarily relate to PPAs whereby the traditional electric operating companies and Southern Power provide electricity and generation capacity 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. Registrants with revenues from contracts with customers related to these performance obligations remaining at June 30, 2019 expect the revenues to be recognized as follows: 2019 (remaining) 2020 2021 2022 2023 Thereafter (in millions) Southern Company $ 282 $ 490 $ 320 $ 311 $ 302 $ 2,230 Alabama Power 11 23 27 23 22 140 Georgia Power 27 51 44 31 31 83 Southern Power 169 295 270 276 269 2,154 Revenues expected to be recognized for performance obligations remaining at June 30, 2019 were immaterial for Mississippi Power.

Consolidated Entities and Equit

Consolidated Entities and Equity Method Investments	6 Months Ended
	Jun. 30, 2019
Regulated Operations [Abstract]
CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS	CONSOLIDATED ENTITIES AND EQUITY METHOD INVESTMENTS Southern Power Consolidated Variable Interest Entities See Note 7 to the financial statements in Item 8 of the Form 10-K for additional information on Southern Power's consolidated VIEs. 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. In 2018, Southern Power sold noncontrolling interests in SP Solar and SP Wind. Southern Power continues to consolidate each entity, as the primary beneficiary of each VIE, since it controls the most significant activities of each entity, including operating and maintaining their assets. Transfers and sales of the assets in the VIEs are subject to limited 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. SP Solar At June 30, 2019 , SP Solar had total assets of $6.5 billion , total liabilities of $374 million , and noncontrolling interests of $1.1 billion . Cash distributions from SP Solar are allocated 67% to Southern Power and 33% to Global Atlantic in accordance with their partnership interest percentage. Under the terms of the limited partnership agreement, distributions without limited partner consent are limited to available cash and SP Solar is obligated to distribute all such available cash to its partners each quarter. Available cash includes all cash generated in the quarter subject to the maintenance of appropriate operating reserves. SP Wind At June 30, 2019 , SP Wind had total assets of $2.5 billion , total liabilities of $136 million , and noncontrolling interests of $46 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. Equity Method Investments In June 2019, Southern Power made investments in certain legal entities that are considered VIEs but for which Southern Power is not the primary beneficiary because it does not control the most significant activities of the VIEs. These investments are accounted for as equity method investments. The total carrying amount of these investments is $144 million as of June 30, 2019, of which $116 million relates to membership interests in DSGP, an affiliate of Bloom Energy, that owns and operates fuel cell generation facilities in Delaware. Southern Power expects to consolidate DSGP, and record a noncontrolling interest, pending FERC approval of the transfer of the facilities. FERC approval is expected to occur in the third quarter 2019; however, the ultimate outcome of this matter cannot be determined at this time. Southern Company Gas See Note 7 to the financial statements in Item 8 of the Form 10-K for additional information on Southern Company Gas' equity method investments. Equity Method Investments The carrying amounts of Southern Company Gas' equity method investments as of June 30, 2019 and December 31, 2018 and related income from those investments for the three - and six -month periods ended June 30, 2019 and 2018 were as follows: Investment Balance June 30, 2019 December 31, 2018 (in millions) SNG $ 1,243 $ 1,261 Atlantic Coast Pipeline 101 83 PennEast Pipeline 77 71 Other (*) 88 123 Total $ 1,509 $ 1,538 (*) Decrease primarily relates to the sale of Triton. Earnings from Equity Method Investments Three Months Ended June 30, 2019 Three Months Ended June 30, 2018 Six Months Ended June 30, 2019 Six Months Ended June 30, 2018 (in millions) SNG $ 32 $ 27 $ 74 $ 66 Atlantic Coast Pipeline 3 1 6 3 PennEast Pipeline 1 1 3 2 Other (*) (5 ) 2 (3 ) 3 Total $ 31 $ 31 $ 80 $ 74 (*) Decrease primarily relates to the sale of Triton. Triton On May 29, 2019, Southern Company Gas sold its investment in Triton, a cargo container leasing company that was aggregated into Southern Company Gas' all other segment. This disposition resulted in a pre-tax loss of $6 million and a net after-tax gain of $7 million as a result of reversing a $13 million federal income tax valuation allowance. SNG Selected financial information of SNG for the three and six months ended June 30, 2019 and 2018 is as follows: Income Statement Information Three Months Ended June 30, 2019 Three Months Ended June 30, 2018 Six Months Ended June 30, 2019 Six Months Ended June 30, 2018 (in millions) Revenues $ 155 $ 146 $ 321 $ 306 Operating income 86 60 192 159 Net income 64 54 148 132

Financing

Financing	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
FINANCING	FINANCING Bank Credit Arrangements Bank credit arrangements provide liquidity support to the registrants' commercial paper borrowings and the traditional electric operating companies' revenue bonds. The amount of variable rate revenue bonds of the traditional electric operating companies outstanding requiring liquidity support as of June 30, 2019 was approximately $1.4 billion (comprised of approximately $854 million at Alabama Power, $550 million at Georgia Power, and $40 million at Mississippi Power). In addition, at June 30, 2019 , the traditional electric operating companies had approximately $272 million (comprised of approximately $87 million at Alabama Power and $185 million at Georgia Power) of revenue bonds outstanding that were required to be remarketed within the next 12 months. See Note 8 to the financial statements under "Bank Credit Arrangements" in Item 8 of the Form 10-K and " Financing Activities " herein for additional information. The following table outlines the committed credit arrangements by company as of June 30, 2019 : Expires Company 2019 2020 2022 2024 Total Unused Due within One Year (in millions) Southern Company (a) $ — $ — $ — $ 2,000 $ 2,000 $ 1,999 $ — Alabama Power 3 500 — 800 1,303 1,303 3 Georgia Power — — — 1,750 1,750 1,736 — Mississippi Power — — 150 — 150 150 — Southern Power (b) — — — 600 600 561 — Southern Company Gas (c) — — — 1,750 1,750 1,745 — Other — 30 — — 30 30 30 Southern Company Consolidated $ 3 $ 530 $ 150 $ 6,900 $ 7,583 $ 7,524 $ 33 (a) Represents the Southern Company parent entity. (b) Does not include Southern Power Company's $120 million continuing letter of credit facility for standby letters of credit expiring in 2021, of which $30 million was unused at June 30, 2019 . Southern Power's subsidiaries are not parties to its bank credit arrangement. (c) Southern Company Gas, as the parent entity, guarantees the obligations of Southern Company Gas Capital, which is the borrower of $1.25 billion of this arrangement. Southern Company Gas' committed credit arrangement also includes $500 million for which Nicor Gas is the borrower and which is restricted for working capital needs of Nicor Gas. Pursuant to this multi-year credit arrangement, the allocations between Southern Company Gas Capital and Nicor Gas may be adjusted. As reflected in the table above, in May 2019, Southern Company, Alabama Power, Georgia Power, and Southern Power each amended and restated certain of their multi-year credit arrangements, which, among other things, extended the maturity dates to 2024. Southern Power also decreased its borrowing capacity from $750 million to $600 million . In addition, Southern Company Gas Capital, along with Nicor Gas, amended and restated its multi-year credit arrangement to extend the maturity date to 2024 and decrease the aggregate borrowing capacity from $1.9 billion to $1.75 billion . In June 2019, Mississippi Power entered into a new $50 million credit arrangement that matures in 2022 and amended its existing credit arrangements, which, among other things, extended the maturity dates from 2019 to 2022. 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. DOE Loan Guarantee Borrowings See Note 8 to the financial statements under "Long-term Debt – DOE Loan Guarantee Borrowings" in Item 8 of the Form 10-K for additional information regarding Georgia Power's 2014 loan guarantee agreement. Pursuant to the loan guarantee program established under Title XVII of the Energy Policy Act of 2005 (Title XVII Loan Guarantee Program), Georgia Power and the DOE entered into a loan guarantee agreement in 2014 and the Amended and Restated Loan Guarantee Agreement in March 2019. Under the Amended and Restated Loan Guarantee Agreement, the DOE has agreed to guarantee the obligations of Georgia Power under note purchase agreements among the DOE, Georgia Power, and the FFB and related promissory notes which provide for two multi-advance term loan facilities (FFB Credit Facilities). Under the FFB Credit Facilities, Georgia Power may make term loan borrowings through the FFB in an amount up to approximately $5.130 billion , provided that total aggregate borrowings under the FFB Credit Facilities may not exceed 70% of (i) Eligible Project Costs minus (ii) approximately $1.492 billion (reflecting the amounts received by Georgia Power under the Guarantee Settlement Agreement less the Customer Refunds). In March 2019, Georgia Power made borrowings under the FFB Credit Facilities in an aggregate principal amount of $835 million at an interest rate of 3.213% through the final maturity date of February 20, 2044. At June 30, 2019 , Georgia Power had a total of $3.46 billion of borrowings outstanding under the FFB Credit Facilities. All borrowings under the FFB Credit Facilities are full recourse to Georgia Power, and Georgia Power is obligated to reimburse the DOE for any payments the DOE is required to make to the FFB under its guarantee. Georgia Power's reimbursement obligations to the DOE are full recourse and secured by a first priority lien on (i) Georgia Power's 45.7% undivided ownership interest in Plant Vogtle Units 3 and 4 (primarily the units under construction, the related real property, and any nuclear fuel loaded in the reactor core) and (ii) Georgia Power's rights and obligations under the principal contracts relating to Plant Vogtle Units 3 and 4. There are no restrictions on Georgia Power's ability to grant liens on other property. In addition to the conditions described above, future advances are subject to satisfaction of customary conditions, as well as certification of compliance with the requirements of the Title XVII Loan Guarantee Program, including accuracy of project-related representations and warranties, delivery of updated project-related information, and evidence of compliance with the prevailing wage requirements of the Davis-Bacon Act of 1931, as amended, and certification from the DOE's consulting engineer that proceeds of the advances are used to reimburse Eligible Project Costs. Upon satisfaction of all conditions described above, advances may be requested on a quarterly basis through 2023. The final maturity date for each advance under the FFB Credit Facilities is February 20, 2044. Interest is payable quarterly and principal payments will begin on February 20, 2020. Borrowings under the FFB Credit Facilities will bear interest at the applicable U.S. Treasury rate plus a spread equal to 0.375% . Under the Amended and Restated Loan Guarantee Agreement, Georgia Power is subject to customary borrower affirmative and negative covenants and events of default. In addition, Georgia Power is subject to project-related reporting requirements and other project-specific covenants and events of default. In the event certain mandatory prepayment events occur, the FFB's commitment to make further advances under the FFB Credit Facilities will terminate and Georgia Power will be required to prepay the outstanding principal amount of all borrowings under the FFB Credit Facilities over a period of five years (with level principal amortization). Among other things, these mandatory prepayment events include (i) the termination of the Vogtle Services Agreement or rejection of the Vogtle Services Agreement in any Westinghouse bankruptcy if Georgia Power does not maintain access to intellectual property rights under the related intellectual property licenses; (ii) termination of the Bechtel Agreement, unless the Vogtle Owners enter into a replacement agreement; (iii) cancellation of Plant Vogtle Units 3 and 4 by the Georgia PSC or by Georgia Power; (iv) failure of the holders of 90% of the ownership interests in Plant Vogtle Units 3 and 4 to vote to continue construction following certain schedule extensions; (v) cost disallowances by the Georgia PSC that could have a material adverse effect on completion of Plant Vogtle Units 3 and 4 or Georgia Power's ability to repay the outstanding borrowings under the FFB Credit Facilities; or (vi) loss of or failure to receive necessary regulatory approvals. Under certain circumstances, insurance proceeds and any proceeds from an event of taking must be applied to immediately prepay outstanding borrowings under the FFB Credit Facilities. In addition, if Georgia Power discontinues construction of Plant Vogtle Units 3 and 4, Georgia Power would be obligated to immediately repay a portion of the outstanding borrowings under the FFB Credit Facilities to the extent such outstanding borrowings exceed 70% of Eligible Project Costs, net of the proceeds received by Georgia Power under the Guarantee Settlement Agreement less the Customer Refunds. Georgia Power also may voluntarily prepay outstanding borrowings under the FFB Credit Facilities. Under the FFB Credit Facilities, any prepayment (whether mandatory or optional) will be made with a make-whole premium or discount, as applicable. In connection with any cancellation of Plant Vogtle Units 3 and 4, the DOE may elect to continue construction of Plant Vogtle Units 3 and 4. In such an event, the DOE will have the right to assume Georgia Power's rights and obligations under the principal agreements relating to Plant Vogtle Units 3 and 4 and to acquire all or a portion of Georgia Power's ownership interest in Plant Vogtle Units 3 and 4. Financing Activities The following table outlines the long-term debt financing activities for Southern Company and its subsidiaries for the first six months of 2019 : Company Senior Note Maturities, Redemptions, and Repurchases Revenue Bond Issuances and Reofferings of Purchased Bonds Revenue Bond and Other Long-Term Debt Issuances Other Long-Term Debt Redemptions and Maturities (a) (in millions) Southern Company (b) $ 2,100 $ — $ — $ — $ — Alabama Power 200 — — — — Georgia Power — 513 223 835 3 Mississippi Power — 43 — — — Other — — 25 — 9 Southern Company Consolidated $ 2,300 $ 556 $ 248 $ 835 $ 12 (a) Includes reductions in finance lease obligations resulting from cash payments under finance leases. (b) Represents the Southern Company parent entity. Except as otherwise described herein, Southern Company and its subsidiaries used the proceeds of debt issuances for their redemptions and maturities shown in the table above, to repay short-term indebtedness, and for general corporate purposes, including working capital. The subsidiaries also used the proceeds for their construction programs. Southern Company In January 2019, Southern Company repaid a $250 million short-term uncommitted bank credit arrangement and a $1.5 billion short-term floating rate bank loan. Also in January 2019, through cash tender offers, Southern Company repurchased and retired approximately $522 million of the $1.0 billion aggregate principal amount outstanding of its 1.85% Senior Notes due July 1, 2019 ( 1.85% Notes), approximately $180 million of the $350 million aggregate principal amount outstanding of its Series 2014B 2.15% Senior Notes due September 1, 2019 (Series 2014B Notes), and approximately $504 million of the $750 million aggregate principal amount outstanding of its Series 2018A Floating Rate Notes due February 14, 2020 (Series 2018A Notes), for an aggregate purchase price, excluding accrued and unpaid interest, of approximately $1.2 billion . In addition, following the completion of the cash tender offers, in February 2019, Southern Company completed the redemption of all of the Series 2018A Notes, 1.85% Notes, and Series 2014B Notes remaining outstanding. Georgia Power In January 2019, Georgia Power redeemed approximately $13 million , $20 million , and $75 million aggregate principal amount of Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), First Series 1992, Eighth Series 1994, and Second Series 1995, respectively. In March 2019, Georgia Power reoffered to the public the following pollution control revenue bonds that previously had been purchased and held by Georgia Power: • $173 million aggregate principal amount of Development Authority of Bartow County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Bowen Project), First Series 2009; • approximately $105 million aggregate principal amount of Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), First Series 2013; and • $65 million aggregate principal amount of Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Second Series 2008. In April 2019, Georgia Power purchased and held the following pollution control revenue bonds. In May 2019, Georgia Power reoffered these pollution control revenue bonds to the public. • $55 million aggregate principal amount of Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Fourth Series 1994; • $30 million aggregate principal amount of Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Fourth Series 1995; • $20 million aggregate principal amount of Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Ninth Series 1994; and • $10 million aggregate principal amount of Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Second Series 1994. In June 2019, Georgia Power reoffered to the public $55 million aggregate principal amount of Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Fifth Series 1994, which had been previously purchased and held by Georgia Power. Also in June 2019, Georgia Power entered into two short-term floating rate bank loans in aggregate principal amounts of $125 million each, both of which bear interest based on one-month LIBOR. Mississippi Power In March 2019, Mississippi Power reoffered to the public $43 million of Mississippi Business Finance Corporation Pollution Control Revenue Refunding Bonds, Series 2002, which previously had been purchased and held by Mississippi Power. Southern Power In May 2019, Southern Power repaid at maturity a $100 million aggregate principal amount short-term bank loan. Earnings per Share For Southern Company, the only difference in computing basic and diluted earnings per share is attributable to awards outstanding under stock-based compensation plans. See Note 12 to the financial statements in Item 8 of the Form 10-K for information on stock-based compensation plans. The effect of stock-based compensation plans was determined using the treasury stock method. Shares used to compute diluted earnings per share were as follows: Three Months Ended June 30, 2019 Three Months Ended June 30, 2018 Six Months Ended June 30, 2019 Six Months Ended June 30, 2018 (in millions) As reported shares 1,044 1,014 1,041 1,012 Effect of stock-based compensation 8 — 8 5 Diluted shares 1,052 1,014 1,049 1,017 There were no stock-based compensation awards that were not included in the diluted earnings per share calculation because they were anti-dilutive for the three and six months ended June 30, 2019 and an immaterial amount of such awards was not included for the six months ended June 30, 2018 . For the three months ended June 30, 2018, approximately 5.3 million shares of stock-based compensation awards were not included in the diluted earnings per share calculation because they were anti-dilutive.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2019
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 Carryforwards Southern Company had federal ITC and PTC carryforwards (primarily related to Southern Power) totaling $2.0 billion as of June 30, 2019 compared to $2.4 billion as of December 31, 2018. The federal ITC and PTC carryforwards begin expiring in 2034 and 2032, respectively, but are expected to be fully utilized by 2023. The estimated tax credit utilization reflects the projected taxable gains on the various sale transactions describe in Note (K) and could be further delayed by numerous factors, including the acquisition of additional renewable projects, the purchase of rights to additional PTCs of Plant Vogtle Units 3 and 4 pursuant to certain joint ownership agreements, and changes in taxable income projections. 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 regarding Plant Vogtle Units 3 and 4. Effective Tax Rate Details of significant changes in the effective tax rate for the applicable registrants are provided herein. Southern Company Southern Company's effective tax rate is typically lower than the statutory rate due to employee stock plans' dividend deduction, non-taxable AFUDC equity and flowback of excess deferred income taxes at the regulated utilities, and federal income tax benefits from ITCs and PTCs, primarily at Southern Power. Southern Company's effective tax rate was 33.5% for the six months ended June 30, 2019 compared to an effective tax benefit rate of (3.2)% for the corresponding period in 2018 . The effective tax rate increase was primarily due to the tax impact from the sale of Gulf Power in 2019 and the 2018 charge to earnings related to the construction of Plant Vogtle Units 3 and 4. See Note (K) and Note 2 to the financial statements in Item 8 of the Form 10-K under "Georgia Power – Nuclear Construction" for additional information. Georgia Power Georgia Power's effective tax rate was 21.7% for the six months ended June 30, 2019 compared to a benefit rate of (53.5)% for the corresponding period in 2018. The effective tax rate increase was primarily due to the 2018 charge to earnings related to the construction of Plant Vogtle Units 3 and 4, partially offset by an increase in state ITCs. See Note 2 to the financial statements in Item 8 of the Form 10-K under "Georgia Power – Nuclear Construction" for additional information. Mississippi Power Mississippi Power's effective tax rate was 14.0% for the six months ended June 30, 2019 compared to 18.7% for the corresponding period in 2018 . The effective tax rate decrease was primarily due to an increase in the flowback of excess deferred income taxes as a result of a settlement agreement reached with wholesale customers under the MRA tariff. See Note (B) under "Mississippi Power" for additional information. Southern Power Southern Power's effective tax benefit rate was (35.5)% for the six months ended June 30, 2019 compared to (1,386.5)% for the corresponding period in 2018 . The effective tax benefit rate decrease was primarily due to reductions of tax benefits from wind PTCs primarily as a result of the 2018 sale of the noncontrolling tax equity interest in SPC Wind and from changes in state apportionment rates following the reorganization of Southern Power's legal entities that own and operate certain solar facilities, partially offset by the net tax benefits from the sale of Plant Nacogdoches in 2019. See Note (K) and Note 15 to the financial statements in Item 8 of the Form 10-K under "Southern Power" for additional information. Southern Company Gas Southern Company Gas' effective tax rate was 18.0% for the six months ended June 30, 2019 compared to 39.1% for the corresponding period in 2018 . This decrease was primarily related to an increase in the flowback of excess deferred income taxes in 2019, primarily at Atlanta Gas Light as previously authorized by the Georgia PSC, and the reversal of a federal tax valuation allowance in connection with Southern Company Gas' sale of its investment in Triton in 2019, as well as the tax impacts of the Southern Company Gas Dispositions in 2018. See Note (E) under "Southern Company Gas" and Notes 2 and 15 to the financial statements under "Southern Company Gas" in Item 8 of the Form 10-K for additional information.

Retirement Benefits

Retirement Benefits	6 Months Ended
	Jun. 30, 2019
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, 2019 . 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. 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 and six months ended June 30, 2019 and 2018 are presented in the following tables. Three Months Ended June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Pension Plans Service cost $ 73 $ 17 $ 18 $ 3 $ 1 $ 6 Interest cost 123 29 39 5 2 9 Expected return on plan assets (221 ) (52 ) (73 ) (10 ) (3 ) (15 ) Amortization: Prior service costs 1 1 1 — — — Regulatory asset — — — — — 4 Net (gain)/loss 30 9 11 2 — — Net periodic pension cost (income) $ 6 $ 4 $ (4 ) $ — $ — $ 4 Postretirement Benefits Service cost $ 4 $ 1 $ 1 $ — $ — $ — Interest cost 17 4 6 1 — 3 Expected return on plan assets (17 ) (7 ) (6 ) (1 ) — (1 ) Amortization: Prior service costs 1 1 — — — — Regulatory asset — — — — — 1 Net (gain)/loss — — — — — (1 ) Net periodic postretirement benefit cost $ 5 $ (1 ) $ 1 $ — $ — $ 2 Six Months Ended June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Pension Plans Service cost $ 146 $ 34 $ 37 $ 6 $ 3 $ 12 Interest cost 246 57 78 11 3 18 Expected return on plan assets (442 ) (103 ) (146 ) (20 ) (5 ) (30 ) Amortization: Prior service costs 1 1 1 — — (1 ) Regulatory asset — — — — — 7 Net (gain)/loss 60 18 22 3 — 1 Net periodic pension cost (income) $ 11 $ 7 $ (8 ) $ — $ 1 $ 7 Postretirement Benefits Service cost $ 9 $ 2 $ 2 $ — $ — $ 1 Interest cost 34 8 13 2 — 5 Expected return on plan assets (33 ) (13 ) (12 ) (1 ) — (3 ) Amortization: Prior service costs 2 2 — — — — Regulatory asset — — — — — 3 Net (gain)/loss (1 ) — — — — (2 ) Net periodic postretirement benefit cost $ 11 $ (1 ) $ 3 $ 1 $ — $ 4 Three Months Ended June 30, 2018 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Pension Plans Service cost $ 89 $ 20 $ 21 $ 4 $ 2 $ 8 Interest cost 116 25 35 5 2 9 Expected return on plan assets (235 ) (53 ) (74 ) (10 ) (2 ) (17 ) Amortization: Prior service costs 1 1 1 — — — Regulatory asset — — — — — 4 Net (gain)/loss 54 13 17 2 — 3 Net periodic pension cost (income) $ 25 $ 6 $ — $ 1 $ 2 $ 7 Postretirement Benefits Service cost $ 6 $ 2 $ 1 $ 1 $ — $ — Interest cost 18 4 7 1 — 3 Expected return on plan assets (17 ) (7 ) (7 ) (1 ) — (2 ) Amortization: Prior service costs 1 1 1 — — — Regulatory asset — — — — — 2 Net (gain)/loss 4 1 2 — — — Net periodic postretirement benefit cost $ 12 $ 1 $ 4 $ 1 $ — $ 3 Six Months Ended June 30, 2018 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Pension Plans Service cost $ 179 $ 39 $ 43 $ 8 $ 4 $ 16 Interest cost 232 50 70 10 3 19 Expected return on plan assets (471 ) (104 ) (148 ) (20 ) (5 ) (35 ) Amortization: Prior service costs 2 1 1 — — (1 ) Regulatory asset — — — — — 7 Net (gain)/loss 107 27 34 5 1 6 Net periodic pension cost (income) $ 49 $ 13 $ — $ 3 $ 3 $ 12 Postretirement Benefits Service cost $ 12 $ 3 $ 3 $ 1 $ — $ 1 Interest cost 37 8 14 2 — 5 Expected return on plan assets (34 ) (13 ) (13 ) (1 ) — (4 ) Amortization: Prior service costs 3 2 1 — — — Regulatory asset — — — — — 3 Net (gain)/loss 7 1 4 — — — Net periodic postretirement benefit cost $ 25 $ 1 $ 9 $ 2 $ — $ 5

Fair Value Measurements

Fair Value Measurements	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS As of June 30, 2019 , 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: As of June 30, 2019: Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Net Asset Value as a Practical Expedient (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 270 $ 177 $ 12 $ — $ 459 Foreign currency derivatives — 60 — — 60 Investments in trusts: (b)(c) Domestic equity 703 124 — — 827 Foreign equity 62 206 — — 268 U.S. Treasury and government agency securities — 307 — — 307 Municipal bonds — 72 — — 72 Pooled funds – fixed income — 16 — — 16 Corporate bonds 23 299 — — 322 Mortgage and asset backed securities — 74 — — 74 Private equity — — — 54 54 Cash and cash equivalents 1 — — — 1 Other 27 2 — — 29 Cash equivalents 841 5 — — 846 Other investments 9 17 — — 26 Total $ 1,936 $ 1,359 $ 12 $ 54 $ 3,361 Liabilities: Energy-related derivatives (a) $ 405 $ 189 $ 22 $ — $ 616 Interest rate derivatives — 52 — — 52 Foreign currency derivatives — 23 — — 23 Contingent consideration — — 21 — 21 Total $ 405 $ 264 $ 43 $ — $ 712 Fair Value Measurements Using: As of June 30, 2019: Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Net Asset Value as a Practical Expedient (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 6 $ — $ — $ 6 Nuclear decommissioning trusts: (b) Domestic equity 456 113 — — 569 Foreign equity 62 60 — — 122 U.S. Treasury and government agency securities — 21 — — 21 Municipal bonds — 1 — — 1 Corporate bonds 23 141 — — 164 Mortgage and asset backed securities — 25 — — 25 Private equity — — — 54 54 Other 7 — — — 7 Cash equivalents 430 5 — — 435 Other investments — 17 — — 17 Total $ 978 $ 389 $ — $ 54 $ 1,421 Liabilities: Energy-related derivatives $ — $ 18 $ — $ — $ 18 Georgia Power Assets: Energy-related derivatives $ — $ 6 $ — $ — $ 6 Nuclear decommissioning trusts: (b)(c) Domestic equity 247 1 — — 248 Foreign equity — 143 — — 143 U.S. Treasury and government agency securities — 286 — — 286 Municipal bonds — 71 — — 71 Corporate bonds — 158 — — 158 Mortgage and asset backed securities — 50 — — 50 Other 20 2 — — 22 Total $ 267 $ 717 $ — $ — $ 984 Liabilities: Energy-related derivatives $ — $ 43 $ — $ — $ 43 Interest rate derivatives — 37 — — 37 Total $ — $ 80 $ — $ — $ 80 Fair Value Measurements Using: As of June 30, 2019: Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Net Asset Value as a Practical Expedient (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 3 $ — $ — $ 3 Cash equivalents 170 — — — 170 Total $ 170 $ 3 $ — $ — $ 173 Liabilities: Energy-related derivatives $ — $ 19 $ — $ — $ 19 Southern Power Assets: Energy-related derivatives $ — $ 2 $ — $ — $ 2 Foreign currency derivatives — 60 — — 60 Cash equivalents 177 — — — 177 Total $ 177 $ 62 $ — $ — $ 239 Liabilities: Energy-related derivatives $ — $ 4 $ — $ — $ 4 Foreign currency derivatives — 23 — — 23 Contingent consideration — — 21 — 21 Total $ — $ 27 $ 21 $ — $ 48 Southern Company Gas Assets: Energy-related derivatives (a) $ 270 $ 160 $ 12 $ — $ 442 Non-qualified deferred compensation trusts: Domestic equity — 10 — — 10 Foreign equity — 4 — — 4 Pooled funds – fixed income — 16 — — 16 Cash equivalents 1 — — — 1 Total $ 271 $ 190 $ 12 $ — $ 473 Liabilities: Energy-related derivatives (a) $ 405 $ 105 $ 22 $ — $ 532 (a) Energy-related derivatives exclude cash collateral of $178 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. As of June 30, 2019 , approximately $30 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 and six months ended June 30, 2019 and 2018. The changes were recorded as a change to the regulatory assets and liabilities related to AROs for Georgia Power and Alabama Power, respectively. Three Months Ended June 30, 2019 Three Months Ended June 30, 2018 Six Months Ended June 30, 2019 Six Months Ended June 30, 2018 (in millions) Southern Company $ 75 $ 14 $ 227 $ 4 Alabama Power 38 15 125 10 Georgia Power 37 (1 ) 102 (6 ) 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 Southern Power 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 obligation is 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. As of June 30, 2019 , 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 $54 million and unfunded commitments related to the private equity investments totaled $45 million . Private equity funds include funds-of-funds that invest in high-quality private equity funds across several market sectors, funds that invest in real estate assets, and a fund that acquires companies to create resale value. Private equity funds do not have redemption rights. Distributions from these funds will be received as the underlying investments in the funds are liquidated. As of June 30, 2019 , other financial instruments for which the carrying amount did not equal fair value were as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (*) (in millions) Long-term debt, including securities due within one year: Carrying amount $ 42,596 $ 7,922 $ 10,969 $ 1,618 $ 5,011 $ 5,916 Fair value 45,394 8,717 11,749 1,657 5,261 6,420 (*) 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 lives of the respective bonds. 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 Southern Company, Alabama Power, Georgia Power, Mississippi Power, Southern Power, and Southern Company Gas. Commodity Contracts with Level 3 Valuation Inputs As of June 30, 2019 , the fair value of Southern Company Gas' Level 3 physical natural gas forward contracts was $10 million . Since commodity contracts classified as Level 3 typically include a combination of observable and unobservable components, the changes in fair value may include amounts due in part to observable market factors, or changes to assumptions on the unobservable components. The following table includes transfers to Level 3, which represent the fair value of Southern Company Gas' commodity derivative contracts that include a significant unobservable component for the first time during the period. Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 (in millions) Beginning balance $ (19 ) $ — Transfers to Level 3 (3 ) (33 ) Changes in fair value 12 23 Ending balance $ (10 ) $ (10 ) Changes in fair value of Level 3 instruments represent changes in gains and losses for the periods that are reported on Southern Company Gas' statements of income in natural gas revenues. The valuation of certain commodity contracts requires the use of certain unobservable inputs. All forward pricing used in the valuation of such contracts is directly based on third-party market data, such as broker quotes and exchange settlements, when that data is available. If third-party market data is not available, then industry standard methodologies are used to develop inputs that maximize the use of relevant observable inputs and minimize the use of unobservable inputs. Observable inputs, including some forward prices used for determining fair value, reflect the best available market information. Unobservable inputs are updated using industry standard techniques such as extrapolation, combining observable forward inputs supplemented by historical market and other relevant data. Level 3 physical natural gas forward contracts include unobservable forward price inputs (ranging from $0.09 to $1.39 per mmBtu). Forward price increases (decreases) as of June 30, 2019 would have resulted in higher (lower) values on a net basis.

Derivatives

Derivatives	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
DERIVATIVES	DERIVATIVES Southern Company, the traditional electric operating companies, Southern Power, and Southern Company Gas 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. Southern Company Gas' wholesale gas operations use various contracts in its commercial activities that generally meet 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 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. Energy-Related Derivatives The traditional electric operating companies, Southern Power, and Southern Company Gas 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 of operating margins 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 the respective fuel cost recovery clauses. • 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 June 30, 2019 , 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 Purchased mmBtu Longest Hedge Date Longest Non-Hedge Date (in millions) Southern Company (*) 536 2023 2029 Alabama Power 88 2022 — Georgia Power 200 2022 — Mississippi Power 101 2023 — Southern Power 8 2020 — Southern Company Gas (*) 139 2021 2029 (*) 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 4.0 billion mmBtu and short natural gas positions of 3.9 billion mmBtu as of June 30, 2019 , 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 25 million mmBtu for Southern Company, which includes 4 million mmBtu for Alabama Power, 8 million mmBtu for Georgia Power, 4 million mmBtu for Mississippi Power, and 9 million mmBtu for Southern Power. For cash flow hedges of energy-related derivatives, the estimated pre-tax gains (losses) expected to be reclassified from accumulated OCI to earnings for the 12 -month period ending June 30, 2020 are immaterial for all registrants. Interest Rate Derivatives Southern Company and certain subsidiaries may enter into interest rate derivatives to hedge exposure to changes in interest rates. The derivatives employed as hedging instruments are structured to minimize ineffectiveness. 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 June 30, 2019 , the following interest rate derivatives were outstanding: Notional Amount Interest Rate Received Weighted Average Interest Rate Paid Hedge Maturity Date Fair Value Gain (Loss) at June 30, 2019 (in millions) (in millions) Cash Flow Hedges of Forecasted Debt Georgia Power $ 250 3-month LIBOR 2.23% March 2025 $ (6 ) Georgia Power 250 3-month LIBOR 2.39% September 2029 (10 ) Georgia Power 250 3-month LIBOR 2.40% March 2030 (9 ) Georgia Power 250 3-month LIBOR 2.48% February 2044 (12 ) Fair Value Hedges of Existing Debt Southern Company (*) 300 2.75% 3-month LIBOR+0.92% June 2020 (1 ) Southern Company (*) 1,500 2.35% 1-month LIBOR+0.87% July 2021 (14 ) Georgia Power 200 4.25% 3-month LIBOR+2.46% December 2019 (1 ) Southern Company Consolidated $ 3,000 $ (53 ) (*) Represents the Southern Company parent entity. The estimated pre-tax gains (losses) related to interest rate derivatives expected to be reclassified from accumulated OCI to interest expense for the 12 -month period ending June 30, 2020 are $(18) million for Southern Company and immaterial for all other registrants. Deferred gains and losses related to interest rate derivatives are expected to be amortized into earnings through 2046 for the Southern Company parent entity, 2035 for Alabama Power, 2044 for 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. The derivatives employed as hedging instruments are structured to minimize ineffectiveness. At June 30, 2019 , the following foreign currency derivatives were outstanding: Pay Notional Pay Rate Receive Notional Receive Rate Hedge Fair Value Gain (Loss) at June 30, 2019 (in millions) (in millions) (in millions) Cash Flow Hedges of Existing Debt Southern Power $ 677 2.95% € 600 1.00% June 2022 $ 14 Southern Power 564 3.78% 500 1.85% June 2026 23 Total $ 1,241 € 1,100 $ 37 The estimated pre-tax gains (losses) related to Southern Power's foreign currency derivatives expected to be reclassified from accumulated OCI to earnings for the 12 -month period ending June 30, 2020 are $(23) million . Derivative Financial Statement Presentation and Amounts Southern Company, the traditional electric operating companies, Southern Power, and Southern Company Gas 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 sheet 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: As of June 30, 2019 As of December 31, 2018 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: Other current assets/Other current liabilities $ 7 $ 57 $ 8 $ 23 Other deferred charges and assets/Other deferred credits and liabilities 9 34 9 26 Assets held for sale, current/Liabilities held for sale, current — — — 6 Total derivatives designated as hedging instruments for regulatory purposes $ 16 $ 91 $ 17 $ 55 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Other current assets/Other current liabilities $ 1 $ 7 $ 3 $ 7 Other deferred charges and assets/Other deferred credits and liabilities — 1 1 2 Interest rate derivatives: Other current assets/Other current liabilities — 50 — 19 Other deferred charges and assets/Other deferred credits and liabilities — 2 — 30 Foreign currency derivatives: Other current assets/Other current liabilities — 23 — 23 Other deferred charges and assets/Other deferred credits and liabilities 60 — 75 — Total derivatives designated as hedging instruments in cash flow and fair value hedges $ 61 $ 83 $ 79 $ 81 Derivatives not designated as hedging instruments Energy-related derivatives: Other current assets/Other current liabilities $ 286 $ 298 $ 561 $ 575 Other deferred charges and assets/Other deferred credits and liabilities 156 219 180 325 Total derivatives not designated as hedging instruments $ 442 $ 517 $ 741 $ 900 Gross amounts recognized $ 519 $ 691 $ 837 $ 1,036 Gross amounts offset (a) $ (328 ) $ (506 ) $ (524 ) $ (801 ) Net amounts recognized in the Balance Sheets (b) $ 191 $ 185 $ 313 $ 235 As of June 30, 2019 As of December 31, 2018 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 $ 4 $ 11 $ 3 $ 4 Other deferred charges and assets/Other deferred credits and liabilities 2 7 3 6 Total derivatives designated as hedging instruments for regulatory purposes $ 6 $ 18 $ 6 $ 10 Gross amounts recognized $ 6 $ 18 $ 6 $ 10 Gross amounts offset $ (3 ) $ (3 ) $ (4 ) $ (4 ) Net amounts recognized in the Balance Sheets $ 3 $ 15 $ 2 $ 6 Georgia Power Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Other current assets/Other current liabilities $ 1 $ 26 $ 2 $ 8 Other deferred charges and assets/Other deferred credits and liabilities 5 17 4 13 Total derivatives designated as hedging instruments for regulatory purposes $ 6 $ 43 $ 6 $ 21 Derivatives designated as hedging instruments in cash flow and fair value hedges Interest rate derivatives: Other current assets/Other current liabilities $ — $ 37 $ — $ 2 Total derivatives designated as hedging instruments in cash flow and fair value hedges $ — $ 37 $ — $ 2 Gross amounts recognized $ 6 $ 80 $ 6 $ 23 Gross amounts offset $ (6 ) $ (6 ) $ (6 ) $ (6 ) Net amounts recognized in the Balance Sheets $ — $ 74 $ — $ 17 As of June 30, 2019 As of December 31, 2018 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) (in millions) Mississippi Power Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Other current assets/Other current liabilities $ 1 $ 10 $ 1 $ 3 Other deferred charges and assets/Other deferred credits and liabilities 2 9 2 6 Total derivatives designated as hedging instruments for regulatory purposes $ 3 $ 19 $ 3 $ 9 Gross amounts recognized $ 3 $ 19 $ 3 $ 9 Gross amounts offset $ (3 ) $ (3 ) $ (2 ) $ (2 ) Net amounts recognized in the Balance Sheets $ — $ 16 $ 1 $ 7 Southern Power Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Other current assets/Other current liabilities $ 1 $ 3 $ 3 $ 6 Other deferred charges and assets/Other deferred credits and liabilities — 1 1 2 Foreign currency derivatives: Other current assets/Other current liabilities — 23 — 23 Other deferred charges and assets/Other deferred credits and liabilities 60 — 75 — Total derivatives designated as hedging instruments in cash flow and fair value hedges $ 61 $ 27 $ 79 $ 31 Derivatives not designated as hedging instruments Energy-related derivatives: Other current assets/Other current liabilities $ 1 $ — $ — $ — Total derivatives not designated as hedging instruments $ 1 $ — $ — $ — Gross amounts recognized $ 62 $ 27 $ 79 $ 31 Gross amounts offset $ (1 ) $ (1 ) $ (3 ) $ (3 ) Net amounts recognized in the Balance Sheets $ 61 $ 26 $ 76 $ 28 As of June 30, 2019 As of December 31, 2018 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/Liabilities from risk management activities-current $ 1 $ 10 $ 2 $ 8 Other deferred charges and assets/Other deferred credits and liabilities — 1 — 1 Total derivatives designated as hedging instruments for regulatory purposes $ 1 $ 11 $ 2 $ 9 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Assets from risk management activities/Liabilities from risk management activities-current $ — $ 4 $ — $ 1 Total derivatives designated as hedging instruments in cash flow and fair value hedges $ — $ 4 $ — $ 1 Derivatives not designated as hedging instruments Energy-related derivatives: Assets from risk management activities/Liabilities from risk management activities-current $ 285 $ 298 $ 559 $ 574 Other deferred charges and assets/Other deferred credits and liabilities 156 219 180 325 Total derivatives not designated as hedging instruments $ 441 $ 517 $ 739 $ 899 Gross amounts of recognized $ 442 $ 532 $ 741 $ 909 Gross amounts offset (a) $ (315 ) $ (493 ) $ (508 ) $ (785 ) Net amounts recognized in the Balance Sheets (b) $ 127 $ 39 $ 233 $ 124 (a) Gross amounts offset include cash collateral held on deposit in broker margin accounts of $178 million and $277 million as of June 30, 2019 and December 31, 2018 , respectively. (b) Net amounts of derivative instruments outstanding exclude premium and intrinsic value associated with weather derivatives of $8 million as of December 31, 2018 . At June 30, 2019 and December 31, 2018 , 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 at June 30, 2019 Derivative Category and Balance Sheet Location Southern Company (*) Alabama Power Georgia Power Mississippi Power Southern Company Gas (*) (in millions) Energy-related derivatives: Other regulatory assets, current $ (48 ) $ (11 ) $ (25 ) $ (10 ) $ (2 ) Other regulatory assets, deferred (23 ) (5 ) (12 ) (6 ) — Other regulatory liabilities, current 6 3 — — 3 Total energy-related derivative gains (losses) $ (65 ) $ (13 ) $ (37 ) $ (16 ) $ 1 (*) Fair value gains and losses recorded in regulatory assets and liabilities include cash collateral held on deposit in broker margin accounts of $12 million at June 30, 2019 . Regulatory Hedge Unrealized Gain (Loss) Recognized in the Balance Sheet at December 31, 2018 Derivative Category and Balance Sheet Location Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) Energy-related derivatives: Other regulatory assets, current $ (19 ) $ (3 ) $ (6 ) $ (2 ) $ (8 ) Other regulatory assets, deferred (16 ) (3 ) (9 ) (4 ) — Assets held for sale, current (6 ) — — — — Other regulatory liabilities, current 1 — — — 1 Total energy-related derivative gains (losses) $ (40 ) $ (6 ) $ (15 ) $ (6 ) $ (7 ) For the three and six months ended June 30, 2019 and 2018 , the pre-tax effects of cash flow hedge accounting on accumulated OCI were as follows: Gain (Loss) Recognized in OCI on Derivative For the Three Months For the Six Months 2019 2018 2019 2018 (in millions) (in millions) Southern Company Energy-related derivatives $ (6 ) $ — $ (6 ) $ 12 Interest rate derivatives (37 ) — (37 ) (2 ) Foreign currency derivatives (1 ) (73 ) (39 ) (21 ) Total $ (44 ) $ (73 ) $ (82 ) $ (11 ) Georgia Power Interest rate derivatives $ (37 ) $ — $ (37 ) $ — Total $ (37 ) $ — $ (37 ) $ — Southern Power Energy-related derivatives $ (2 ) $ (1 ) $ (2 ) $ 10 Foreign currency derivatives (1 ) (73 ) (39 ) (21 ) Total $ (3 ) $ (74 ) $ (41 ) $ (11 ) For the three and six months ended June 30, 2019 and 2018 , the pre-tax effects of energy-related derivatives and interest rate derivatives designated as cash flow hedging instruments on accumulated OCI were immaterial for the other registrants. For the three and six months ended June 30, 2019 and 2018 , 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 For the Six Months 2019 2018 2019 2018 (in millions) (in millions) Southern Company Total depreciation and amortization $ 755 $ 783 $ 1,506 $ 1,552 Gain (loss) on energy-related cash flow hedges (a) (1 ) 1 (4 ) 2 Total interest expense, net of amounts capitalized (429 ) (470 ) (859 ) (928 ) Gain (loss) on interest rate cash flow hedges (a) (5 ) (6 ) (9 ) (11 ) Gain (loss) on foreign currency cash flow hedges (a) (6 ) (7 ) (12 ) (12 ) Gain (loss) on interest rate fair value hedges (b) 19 (7 ) 33 (31 ) Total other income (expense), net 99 78 176 138 Gain (loss) on foreign currency cash flow hedges (a)(c) 16 (73 ) (8 ) (37 ) Southern Power Total depreciation and amortization $ 119 $ 125 $ 237 $ 240 Gain (loss) on energy-related cash flow hedges (a) (1 ) 1 (4 ) 2 Total interest expense, net of amounts capitalized (41 ) (46 ) (84 ) (93 ) Gain (loss) on foreign currency cash flow hedges (a) (6 ) (7 ) (12 ) (12 ) Total other income (expense), net 40 2 41 5 Gain (loss) on foreign currency cash flow hedges (a)(c) 16 (73 ) (8 ) (37 ) (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 and six months ended June 30, 2019 and 2018 , 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 and Southern Company Gas. As of June 30, 2019 and December 31, 2018, 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 As of June 30, 2019 As of December 31, 2018 As of June 30, 2019 As of December 31, 2018 (in millions) (in millions) Southern Company Securities due within one year $ (499 ) $ (498 ) $ 1 $ 2 Long-term debt (2,087 ) (2,052 ) 7 41 Georgia Power Securities due within one year $ (499 ) $ (498 ) $ 1 $ 2 For the three and six months ended June 30, 2019 and 2018 , 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 June 30, Six Months Ended June 30, Derivatives in Non-Designated Hedging Relationships Statements of Income Location 2019 2018 2019 2018 (in millions) (in millions) Southern Company Energy-related derivatives: Natural gas revenues (*) $ 50 $ (28 ) $ 83 $ (43 ) Cost of natural gas (5 ) 2 3 4 Total derivatives in non-designated hedging relationships $ 45 $ (26 ) $ 86 $ (39 ) Southern Company Gas Energy-related derivatives: Natural gas revenues (*) $ 50 $ (28 ) $ 83 $ (43 ) Cost of natural gas (5 ) 2 3 4 Total derivatives in non-designated hedging relationships $ 45 $ (26 ) $ 86 $ (39 ) (*) Excludes immaterial gains (losses) recorded in natural gas revenues associated with weather derivatives for all periods presented. For the three and six months ended June 30, 2019 and 2018 , the pre-tax effects of energy-related derivatives and interest rate derivatives not designated as hedging instruments were immaterial for the traditional electric operating companies and Southern Power. Contingent Features Southern Company, the traditional electric operating companies, Southern Power, and Southern Company Gas 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 June 30, 2019 , the registrants had no collateral posted with derivative counterparties to satisfy these arrangements. For the registrants with interest rate derivatives at June 30, 2019 , the fair value of interest rate derivative liabilities with contingent features and the maximum potential collateral requirements arising from the credit-risk-related contingent features, at a rating below BBB- and/or Baa3, was immaterial. At June 30, 2019 , the fair value of 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 for all registrants. 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, Gulf Power is continuing to participate in the Southern Company power pool for a defined transition period that, subject to certain potential adjustments, is scheduled to end on January 1, 2024. 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. Based on the value of the positions in these accounts and the associated margin requirements, Alabama Power and Southern Power may be required to post collateral. At June 30, 2019 , 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 June 30, 2019 , cash collateral held on deposit in broker margin accounts was $178 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. Prior to entering into a physical transaction, Southern Company Gas assigns physical wholesale counterparties an internal credit rating and credit limit based on the counterparties' Moody's, S&P, and Fitch Ratings Inc. ratings, commercially available credit reports, and audited financial statements. Southern Company Gas may require counterparties to pledge additional collateral when deemed necessary. In addition, Southern Company Gas conducts credit evaluations and obtains appropriate internal approvals for the counterparty's line of credit before any transaction with the counterparty is executed. In most cases, the counterparty must have an investment grade rating, which includes a minimum long-term debt rating of Baa3 from Moody's and BBB- from S&P. Generally, Southern Company Gas requires credit enhancements by way of a guaranty, cash deposit, or letter of credit for transaction counterparties that do not have investment grade ratings. Southern Company Gas also utilizes master netting agreements whenever possible to mitigate exposure to counterparty credit risk. When Southern Company Gas is engaged in more than one outstanding derivative transaction with the same counterparty and it also has a legally enforceable netting agreement with that counterparty, the "net" mark-to-market exposure represents the netting of the positive and negative exposures with that counterparty and a reasonable measure of Southern Company Gas' credit risk. Southern Company Gas also uses other netting agreements with certain counterparties with whom it conducts significant transactions. Master netting agreements enable Southern Company Gas to net certain assets and liabilities by counterparty. Southern Company Gas also nets across product lines and against cash collateral provided the master netting and cash collateral agreements include such provisions. Southern Company Gas may require counterparties to pledge additional collateral when deemed necessary. 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	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
ACQUISITIONS AND DISPOSITIONS	ACQUISITIONS AND DISPOSITIONS See Note 15 to the financial statements in Item 8 of the Form 10-K for additional information. Southern Company On January 1, 2019, Southern Company completed the sale of all of the capital stock of Gulf Power to 700 Universe, LLC, a wholly-owned subsidiary of NextEra Energy, for an aggregate cash purchase price of approximately $5.8 billion (less $1.3 billion of indebtedness assumed), subject to customary working capital adjustments. The preliminary gain associated with the sale of Gulf Power totaled $2.5 billion pre-tax ( $1.3 billion after tax). The assets and liabilities of Gulf Power were classified as assets held for sale and liabilities held for sale on Southern Company's balance sheet as of December 31, 2018. On July 22, 2019, PowerSecure completed the sale of its utility infrastructure services business unit for approximately $71 million , subject to customary working capital adjustments. The related assets and liabilities were classified as held for sale on Southern Company's balance sheet as of June 30, 2019 . In contemplation of this sale, a goodwill impairment charge of $32 million was recorded in the second quarter 2019. See " Assets Held for Sale " herein for additional information. Southern Power Construction Projects During the six months ended June 30, 2019 , Southern Power completed construction of and placed in service the 385 -MW Plant Mankato expansion and continued construction of two other projects as described in the table below. Total aggregate construction costs, excluding acquisition costs, are expected to be between $405 million and $450 million for the Wildhorse Mountain and Reading facilities. At June 30, 2019 , total costs of construction incurred for these projects were $186 million and are included in CWIP . The ultimate outcome of these matters cannot be determined at this time. Project Facility Resource Approximate Nameplate Capacity ( MW ) Location Actual/Expected COD PPA Contract Period Projects Completed During the Six Months Ended June 30, 2019 Mankato expansion (a) Natural Gas 385 Mankato, MN May 2019 20 years Projects Under Construction as of June 30, 2019 Wildhorse Mountain (b) Wind 100 Pushmataha County, OK Fourth quarter 2019 20 years Reading (c) Wind 200 Osage and Lyon Counties, KS Second quarter 2020 12 years (a) In November 2018, Southern Power entered into an agreement to sell all of its equity interests in Plant Mankato, including this expansion that was completed during May 2019. This transaction is subject to state commission approvals and is expected to close in fall 2019. The expansion unit started providing energy under a PPA with Northern States Power on June 1, 2019. See " Sales of Natural Gas and Biomass Plants " below. (b) In May 2018, Southern Power purchased 100% of the Wildhorse Mountain facility. Southern Power entered into a tax equity partnership in June 2019 with funding of tax equity amounts expected to occur upon commercial operation. (c) In August 2018, Southern Power purchased 100% of the membership interests of the Reading facility from the joint development arrangement with Renewable Energy Systems Americas, Inc. Southern Power may enter into a tax equity partnership, in which case it would then own 100% of the class B membership interests. Development Projects Southern Power continues to evaluate and refine the deployment of wind turbine equipment purchased in 2016 and 2017 to potential joint development and construction projects as well as the amount of MW capacity to be constructed. During the six months ended June 30, 2019, certain wind turbine equipment was sold, resulting in a gain on the sale of approximately $14 million . On June 14, 2019, Southern Power entered into an agreement with Bloom Energy to acquire a majority interest in its affiliate DSGP, which owns and operates fuel cell generation facilities in Delaware, for a total amount not to exceed $173 million . In June 2019, Southern Power, through an affiliate, contributed a total of $116 million in exchange for Class B membership interests in DSGP, with the remainder expected to be contributed by the end of 2019. FERC approval of the transfer of the facilities is expected to occur in the third quarter 2019; however, the ultimate outcome of this matter cannot be determined at this time. Sales of Natural Gas and Biomass Plants On June 13, 2019, Southern Power completed the sale of its equity interests in Nacogdoches Power, LLC, the owner of an approximately 115 -MW biomass facility located in Nacogdoches County, Texas, to Austin Energy, for an aggregate cash purchase price of approximately $461 million , including working capital adjustments. This sale resulted in an $88 million after-tax gain. On May 4, 2019, Southern Power achieved commercial operation of the 385 -MW natural gas expansion unit at Plant Mankato and started providing energy under a PPA with Northern States Power on June 1, 2019. The sale of Plant Mankato to Northern States Power remains subject to Minnesota and North Dakota state commission approvals and is expected to close in fall 2019. If these state commission approvals are not obtained by October 1, 2019, either party has the option to terminate the sale, which, if elected, would result in the payment of a $15 million termination fee by Northern States Power to Southern Power. The ultimate outcome of this matter cannot be determined at this time. The assets and liabilities of Plant Mankato are classified as assets held for sale and liabilities held for sale on Southern Company's and Southern Power's balance sheets as of June 30, 2019 and December 31, 2018. See " Assets Held for Sale " herein for additional information. Assets Subject to Lien Under the terms of the PPAs for Plant Mankato, approximately $545 million of assets, primarily related to property, plant, and equipment, are subject to lien at June 30, 2019 . Assets Held for Sale As discussed above, Southern Company and Southern Power each have assets and liabilities held for sale on their balance sheets at June 30, 2019 and December 31, 2018. Assets and liabilities held for sale have been classified separately on each company's balance sheet at the lower of carrying value or fair value less costs to sell at the time the criteria for held-for-sale classification were met. For assets and liabilities held for sale recorded at fair value on a nonrecurring basis, the fair value of assets held for sale is based primarily on unobservable inputs (Level 3), which includes the agreed upon sales prices in executed sales agreements. Upon classification as held for sale in November 2018 and April 2019 for Plant Mankato and Plant Nacogdoches, respectively, Southern Power ceased recognizing depreciation and amortization on the long-lived assets to be sold. The following table provides Southern Company's and Southern Power's major classes of assets and liabilities classified as held for sale at June 30, 2019 and December 31, 2018 : Southern Company Southern Power (in millions) At June 30, 2019 Assets Held for Sale: Current assets $ 58 $ 10 Total property, plant, and equipment 588 559 Goodwill and other intangible assets 51 40 Other non-current assets 46 — Total Assets Held for Sale $ 743 $ 609 Liabilities Held for Sale: Current liabilities $ 36 $ 10 Other non-current liabilities 39 — Total Liabilities Held for Sale $ 75 $ 10 At December 31, 2018 Assets Held for Sale: Current assets $ 393 $ 8 Total property, plant, and equipment 4,583 536 Other intangible assets 40 40 Other non-current assets 727 — Total Assets Held for Sale $ 5,743 $ 584 Liabilities Held for Sale: Current liabilities $ 425 $ 15 Long-term debt 1,286 — Accumulated deferred income taxes 618 — Other non-current liabilities 932 — Total Liabilities Held for Sale $ 3,261 $ 15 Southern Company and Southern Power each concluded that the sale of their assets, both individually and combined, did not represent a strategic shift in operations that has, or is expected to have, a major effect on its operations and financial results; therefore, none of the assets related to the sales have been classified as discontinued operations for any of the periods presented. Gulf Power and Southern Power's equity interests in Plant Oleander and Plant Stanton Unit A (together, the Florida Plants) and Plant Nacogdoches represented individually significant components of Southern Company and Southern Power, respectively; therefore, pre-tax profit for these components for the three and six months ended June 30, 2019 and 2018 is presented below: For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (in millions) Earnings before income taxes: Gulf Power $ — $ 31 $ — $ 87 Southern Power's Florida Plants $ — $ 14 $ — $ 24 Southern Power's Plant Nacogdoches (*) $ 9 $ 7 $ 16 $ 13 (*) Earnings before income taxes for Plant Nacogdoches for the three and six months ended June 30, 2019 represents the beginning of the corresponding period through June 13, 2019 (the divestiture date).

Leases

Leases	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
LEASES	LEASES On January 1, 2019, the registrants adopted the provisions of FASB ASC Topic 842 (as amended), Leases (ASC 842), which require lessees to recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with right-of-use (ROU) assets that will be amortized over the term of each lease. The registrants elected the transition methodology provided by ASC 842, whereby the applicable requirements are applied on a prospective basis as of the adoption date of January 1, 2019, without restating prior periods. The registrants also elected the package of practical expedients provided by ASC 842 that allows prior determinations of whether existing contracts are, or contain, leases and the classification of existing leases to continue without reassessment. Additionally, the registrants applied the use-of-hindsight practical expedient in determining lease terms as of the date of adoption and elected the practical expedient that allows existing land easements not previously accounted for as leases not to be reassessed. Lessee As lessee, the registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows: As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Electric generating units $ 1,072 $ 150 $ 1,580 $ — $ — $ — Real estate/land 800 4 62 2 395 81 Communication towers 147 1 3 — — 13 Railcars 54 25 27 3 — — Other 145 10 14 2 — — Total $ 2,218 $ 190 $ 1,686 $ 7 $ 395 $ 94 Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 25 years while the land leases have remaining terms of up to 48 years, including renewal periods. Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies. Communication tower leases have terms of up to 10 years with options to renew for periods up to 20 years. While renewal options exist in many of the leases, other than for land leases associated with renewable energy facilities, the expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease as it is not considered reasonably certain that the lease will be extended. The expected term of land leases associated with renewable energy facilities includes renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities. Contracts that Contain a Lease While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the affiliate PPA, which varies between four and 18 years. Georgia Power has several PPAs with Southern Power that Georgia Power accounts for as leases with a lease obligation of approximately $660 million at June 30, 2019 . The amount paid for energy under these affiliate PPAs reflects a price that would be paid in an arm's-length transaction as those amounts have been reviewed and approved by the Georgia PSC. Short-term Leases Leases with an initial term of 12 months or less are not recorded on the balance sheet; the registrants generally recognize lease expense for these leases on a straight-line basis over the lease term. Residual Value Guarantees Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power and the amounts probable of being paid under those guarantees are included in the lease payments. All such amounts are immaterial as of June 30, 2019 . Lease and Nonlease Components For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the right-of-use asset. Balance sheet amounts recorded for operating and finance leases are as follows: As of June 30, 2019 Southern Company (*) Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Operating Leases Operating lease ROU assets, net $ 1,907 $ 152 $ 1,492 $ 7 $ 370 $ 95 Operating lease obligations - current $ 241 $ 48 $ 140 $ 2 $ 22 $ 15 Operating lease obligations - non current 1,733 137 1,377 5 373 79 Total operating lease obligations $ 1,974 $ 185 $ 1,517 $ 7 $ 395 $ 94 Finance Leases Finance lease ROU assets, net $ 237 $ 5 $ 142 $ — $ — $ — Finance lease obligations - current $ 24 $ 1 $ 10 $ — $ — $ — Finance lease obligations - noncurrent 220 4 159 — — — Total finance lease obligations $ 244 $ 5 $ 169 $ — $ — $ — (*) Includes operating lease ROU assets, net and operating lease obligations classified as held for sale. Lease costs for the three and six months ended June 30, 2019 , which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) For the Three Months Ended June 30, 2019 Lease cost Operating lease cost $ 77 $ 13 $ 50 $ 1 $ 7 $ 5 Finance lease cost: Amortization of ROU assets 7 — 4 — — — Interest on lease obligations 3 — 4 — — — Total finance lease cost 10 — 8 — — — Short-term lease costs 13 6 6 — — — Variable lease cost 29 1 25 — 1 — Sublease income — — — — — — Total lease cost $ 129 $ 20 $ 89 $ 1 $ 8 $ 5 For the Six Months Ended June 30, 2019 Lease cost Operating lease cost $ 147 $ 20 $ 99 $ 1 $ 14 $ 9 Finance lease cost: Amortization of ROU assets 14 — 7 — — — Interest on lease obligations 6 — 9 — — — Total finance lease cost 20 — 16 — — — Short-term lease costs 30 11 12 — — — Variable lease cost 48 1 41 — 3 — Sublease income — — — — — — Total lease cost $ 245 $ 32 $ 168 $ 1 $ 17 $ 9 Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: For the Six Months Ended June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 129 $ 20 $ 75 $ 1 $ 12 $ 9 Operating cash flows from finance leases 2 — 10 — — — Financing cash flows from finance leases 16 — 3 — — — ROU assets obtained in exchange for new operating lease obligations 55 5 13 — — 13 ROU assets obtained in exchange for new finance lease obligations 33 1 28 — — — As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Weighted-average remaining lease term in years: Operating leases 14.0 3.6 10.5 7.0 33.5 9.7 Finance leases 18.3 12.8 11.0 N/A N/A N/A Weighted-average discount rate: Operating leases 4.53 % 3.33 % 4.46 % 4.06 % 5.68 % 3.73 % Finance leases 5.05 % 3.67 % 10.69 % N/A N/A N/A Maturities of lease liabilities are as follows: As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2019 (remaining) $ 178 $ 33 $ 129 $ 1 $ 13 $ 9 2020 295 53 203 2 22 17 2021 279 52 198 1 23 16 2022 268 52 196 1 23 13 2023 204 4 197 1 24 11 Thereafter 1,661 2 990 2 849 49 Total 2,885 196 1,913 8 954 115 Less: Present value discount 911 11 396 1 559 21 Operating lease obligations $ 1,974 $ 185 $ 1,517 $ 7 $ 395 $ 94 Finance leases: 2019 (remaining) $ 16 $ — $ 16 $ — $ — $ — 2020 33 1 28 — — — 2021 27 1 25 — — — 2022 23 1 25 — — — 2023 18 1 25 — — — Thereafter 266 1 165 — — — Total 383 5 284 — — — Less: Present value discount 139 — 115 — — — Finance lease obligations $ 244 $ 5 $ 169 $ — $ — $ — Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis. As of June 30, 2019 , Southern Company and Southern Power have additional operating leases, primarily for land, that have not yet commenced. These operating leases are expected to commence during the remainder of 2019 through 2022, with lease terms of up to 31 years, and have estimated total obligations of $81 million . For additional information on each registrant's operating lease obligations at December 31, 2018, see Note 9 to the financial statements in Item 8 of the Form 10-K. Lessor With the exception of Southern Company Gas, the registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to five years , after which the contracts renew on a month-to-month basis at the customer's option. For Mississippi Power, these arrangements also include tolling arrangements related to electric generating units accounted for as sales-type leases with terms of up to 20 years. For Southern Power, these arrangements consist of PPAs related to electric generating units, including renewable energy facilities, accounted for as operating leases with terms of up to 28 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with terms of up to 15 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 24 years. Lease income for the three and six months ended June 30, 2019 is as follows: Southern Company Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) For the Three Months Ended June 30, 2019 Lease income - interest income on sales-type leases $ 2 $ — $ 2 $ — $ — Lease income - operating leases 67 19 — 39 9 Variable lease income 115 — — 125 — Total lease income $ 184 $ 19 $ 2 $ 164 $ 9 For the Six Months Ended June 30, 2019 Lease income - interest income on sales-type leases $ 5 $ — $ 5 $ — $ — Lease income - operating leases 139 39 — 80 17 Variable lease income 182 — — 198 — Total lease income $ 326 $ 39 $ 5 $ 278 $ 17 No profit or loss was recognized by Mississippi Power upon commencement of a sales-type lease during the first quarter 2019. Lease income for Southern Power is included in wholesale revenues. 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. Scheduled payments to be received under outdoor lighting contracts, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses. The undiscounted cash flows to be received under tolling arrangements accounted for as sales-type leases are as follows: As of June 30, 2019 Southern Company Mississippi Power (in millions) 2019 (remaining) $ 7 $ 7 2020 14 14 2021 14 14 2022 13 13 2023 12 12 Thereafter 135 135 Total undiscounted cash flows $ 195 $ 195 Lease receivable 106 106 Difference between undiscounted cash flows and discounted cash flows $ 89 $ 89 The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases (adjusted for intercompany eliminations) are as follows: As of June 30, 2019 Southern Company Georgia Power Southern Power Southern Company Gas (in millions) 2019 (remaining) $ 75 $ 13 $ 52 $ 17 2020 125 26 65 35 2021 118 18 66 35 2022 109 8 68 34 2023 103 2 69 34 Thereafter 1,142 — 350 497 Total $ 1,672 $ 67 $ 670 $ 652 Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Southern Power allocates revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under outdoor lighting contracts accounted for as operating leases at Alabama Power and Mississippi Power are immaterial.
LEASES	LEASES On January 1, 2019, the registrants adopted the provisions of FASB ASC Topic 842 (as amended), Leases (ASC 842), which require lessees to recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with right-of-use (ROU) assets that will be amortized over the term of each lease. The registrants elected the transition methodology provided by ASC 842, whereby the applicable requirements are applied on a prospective basis as of the adoption date of January 1, 2019, without restating prior periods. The registrants also elected the package of practical expedients provided by ASC 842 that allows prior determinations of whether existing contracts are, or contain, leases and the classification of existing leases to continue without reassessment. Additionally, the registrants applied the use-of-hindsight practical expedient in determining lease terms as of the date of adoption and elected the practical expedient that allows existing land easements not previously accounted for as leases not to be reassessed. Lessee As lessee, the registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows: As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Electric generating units $ 1,072 $ 150 $ 1,580 $ — $ — $ — Real estate/land 800 4 62 2 395 81 Communication towers 147 1 3 — — 13 Railcars 54 25 27 3 — — Other 145 10 14 2 — — Total $ 2,218 $ 190 $ 1,686 $ 7 $ 395 $ 94 Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 25 years while the land leases have remaining terms of up to 48 years, including renewal periods. Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies. Communication tower leases have terms of up to 10 years with options to renew for periods up to 20 years. While renewal options exist in many of the leases, other than for land leases associated with renewable energy facilities, the expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease as it is not considered reasonably certain that the lease will be extended. The expected term of land leases associated with renewable energy facilities includes renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities. Contracts that Contain a Lease While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the affiliate PPA, which varies between four and 18 years. Georgia Power has several PPAs with Southern Power that Georgia Power accounts for as leases with a lease obligation of approximately $660 million at June 30, 2019 . The amount paid for energy under these affiliate PPAs reflects a price that would be paid in an arm's-length transaction as those amounts have been reviewed and approved by the Georgia PSC. Short-term Leases Leases with an initial term of 12 months or less are not recorded on the balance sheet; the registrants generally recognize lease expense for these leases on a straight-line basis over the lease term. Residual Value Guarantees Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power and the amounts probable of being paid under those guarantees are included in the lease payments. All such amounts are immaterial as of June 30, 2019 . Lease and Nonlease Components For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the right-of-use asset. Balance sheet amounts recorded for operating and finance leases are as follows: As of June 30, 2019 Southern Company (*) Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Operating Leases Operating lease ROU assets, net $ 1,907 $ 152 $ 1,492 $ 7 $ 370 $ 95 Operating lease obligations - current $ 241 $ 48 $ 140 $ 2 $ 22 $ 15 Operating lease obligations - non current 1,733 137 1,377 5 373 79 Total operating lease obligations $ 1,974 $ 185 $ 1,517 $ 7 $ 395 $ 94 Finance Leases Finance lease ROU assets, net $ 237 $ 5 $ 142 $ — $ — $ — Finance lease obligations - current $ 24 $ 1 $ 10 $ — $ — $ — Finance lease obligations - noncurrent 220 4 159 — — — Total finance lease obligations $ 244 $ 5 $ 169 $ — $ — $ — (*) Includes operating lease ROU assets, net and operating lease obligations classified as held for sale. Lease costs for the three and six months ended June 30, 2019 , which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) For the Three Months Ended June 30, 2019 Lease cost Operating lease cost $ 77 $ 13 $ 50 $ 1 $ 7 $ 5 Finance lease cost: Amortization of ROU assets 7 — 4 — — — Interest on lease obligations 3 — 4 — — — Total finance lease cost 10 — 8 — — — Short-term lease costs 13 6 6 — — — Variable lease cost 29 1 25 — 1 — Sublease income — — — — — — Total lease cost $ 129 $ 20 $ 89 $ 1 $ 8 $ 5 For the Six Months Ended June 30, 2019 Lease cost Operating lease cost $ 147 $ 20 $ 99 $ 1 $ 14 $ 9 Finance lease cost: Amortization of ROU assets 14 — 7 — — — Interest on lease obligations 6 — 9 — — — Total finance lease cost 20 — 16 — — — Short-term lease costs 30 11 12 — — — Variable lease cost 48 1 41 — 3 — Sublease income — — — — — — Total lease cost $ 245 $ 32 $ 168 $ 1 $ 17 $ 9 Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: For the Six Months Ended June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 129 $ 20 $ 75 $ 1 $ 12 $ 9 Operating cash flows from finance leases 2 — 10 — — — Financing cash flows from finance leases 16 — 3 — — — ROU assets obtained in exchange for new operating lease obligations 55 5 13 — — 13 ROU assets obtained in exchange for new finance lease obligations 33 1 28 — — — As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Weighted-average remaining lease term in years: Operating leases 14.0 3.6 10.5 7.0 33.5 9.7 Finance leases 18.3 12.8 11.0 N/A N/A N/A Weighted-average discount rate: Operating leases 4.53 % 3.33 % 4.46 % 4.06 % 5.68 % 3.73 % Finance leases 5.05 % 3.67 % 10.69 % N/A N/A N/A Maturities of lease liabilities are as follows: As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2019 (remaining) $ 178 $ 33 $ 129 $ 1 $ 13 $ 9 2020 295 53 203 2 22 17 2021 279 52 198 1 23 16 2022 268 52 196 1 23 13 2023 204 4 197 1 24 11 Thereafter 1,661 2 990 2 849 49 Total 2,885 196 1,913 8 954 115 Less: Present value discount 911 11 396 1 559 21 Operating lease obligations $ 1,974 $ 185 $ 1,517 $ 7 $ 395 $ 94 Finance leases: 2019 (remaining) $ 16 $ — $ 16 $ — $ — $ — 2020 33 1 28 — — — 2021 27 1 25 — — — 2022 23 1 25 — — — 2023 18 1 25 — — — Thereafter 266 1 165 — — — Total 383 5 284 — — — Less: Present value discount 139 — 115 — — — Finance lease obligations $ 244 $ 5 $ 169 $ — $ — $ — Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis. As of June 30, 2019 , Southern Company and Southern Power have additional operating leases, primarily for land, that have not yet commenced. These operating leases are expected to commence during the remainder of 2019 through 2022, with lease terms of up to 31 years, and have estimated total obligations of $81 million . For additional information on each registrant's operating lease obligations at December 31, 2018, see Note 9 to the financial statements in Item 8 of the Form 10-K. Lessor With the exception of Southern Company Gas, the registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to five years , after which the contracts renew on a month-to-month basis at the customer's option. For Mississippi Power, these arrangements also include tolling arrangements related to electric generating units accounted for as sales-type leases with terms of up to 20 years. For Southern Power, these arrangements consist of PPAs related to electric generating units, including renewable energy facilities, accounted for as operating leases with terms of up to 28 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with terms of up to 15 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 24 years. Lease income for the three and six months ended June 30, 2019 is as follows: Southern Company Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) For the Three Months Ended June 30, 2019 Lease income - interest income on sales-type leases $ 2 $ — $ 2 $ — $ — Lease income - operating leases 67 19 — 39 9 Variable lease income 115 — — 125 — Total lease income $ 184 $ 19 $ 2 $ 164 $ 9 For the Six Months Ended June 30, 2019 Lease income - interest income on sales-type leases $ 5 $ — $ 5 $ — $ — Lease income - operating leases 139 39 — 80 17 Variable lease income 182 — — 198 — Total lease income $ 326 $ 39 $ 5 $ 278 $ 17 No profit or loss was recognized by Mississippi Power upon commencement of a sales-type lease during the first quarter 2019. Lease income for Southern Power is included in wholesale revenues. 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. Scheduled payments to be received under outdoor lighting contracts, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses. The undiscounted cash flows to be received under tolling arrangements accounted for as sales-type leases are as follows: As of June 30, 2019 Southern Company Mississippi Power (in millions) 2019 (remaining) $ 7 $ 7 2020 14 14 2021 14 14 2022 13 13 2023 12 12 Thereafter 135 135 Total undiscounted cash flows $ 195 $ 195 Lease receivable 106 106 Difference between undiscounted cash flows and discounted cash flows $ 89 $ 89 The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases (adjusted for intercompany eliminations) are as follows: As of June 30, 2019 Southern Company Georgia Power Southern Power Southern Company Gas (in millions) 2019 (remaining) $ 75 $ 13 $ 52 $ 17 2020 125 26 65 35 2021 118 18 66 35 2022 109 8 68 34 2023 103 2 69 34 Thereafter 1,142 — 350 497 Total $ 1,672 $ 67 $ 670 $ 652 Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Southern Power allocates revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under outdoor lighting contracts accounted for as operating leases at Alabama Power and Mississippi Power are immaterial.
LEASES	LEASES On January 1, 2019, the registrants adopted the provisions of FASB ASC Topic 842 (as amended), Leases (ASC 842), which require lessees to recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with right-of-use (ROU) assets that will be amortized over the term of each lease. The registrants elected the transition methodology provided by ASC 842, whereby the applicable requirements are applied on a prospective basis as of the adoption date of January 1, 2019, without restating prior periods. The registrants also elected the package of practical expedients provided by ASC 842 that allows prior determinations of whether existing contracts are, or contain, leases and the classification of existing leases to continue without reassessment. Additionally, the registrants applied the use-of-hindsight practical expedient in determining lease terms as of the date of adoption and elected the practical expedient that allows existing land easements not previously accounted for as leases not to be reassessed. Lessee As lessee, the registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows: As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Electric generating units $ 1,072 $ 150 $ 1,580 $ — $ — $ — Real estate/land 800 4 62 2 395 81 Communication towers 147 1 3 — — 13 Railcars 54 25 27 3 — — Other 145 10 14 2 — — Total $ 2,218 $ 190 $ 1,686 $ 7 $ 395 $ 94 Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 25 years while the land leases have remaining terms of up to 48 years, including renewal periods. Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies. Communication tower leases have terms of up to 10 years with options to renew for periods up to 20 years. While renewal options exist in many of the leases, other than for land leases associated with renewable energy facilities, the expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease as it is not considered reasonably certain that the lease will be extended. The expected term of land leases associated with renewable energy facilities includes renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities. Contracts that Contain a Lease While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the affiliate PPA, which varies between four and 18 years. Georgia Power has several PPAs with Southern Power that Georgia Power accounts for as leases with a lease obligation of approximately $660 million at June 30, 2019 . The amount paid for energy under these affiliate PPAs reflects a price that would be paid in an arm's-length transaction as those amounts have been reviewed and approved by the Georgia PSC. Short-term Leases Leases with an initial term of 12 months or less are not recorded on the balance sheet; the registrants generally recognize lease expense for these leases on a straight-line basis over the lease term. Residual Value Guarantees Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power and the amounts probable of being paid under those guarantees are included in the lease payments. All such amounts are immaterial as of June 30, 2019 . Lease and Nonlease Components For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the right-of-use asset. Balance sheet amounts recorded for operating and finance leases are as follows: As of June 30, 2019 Southern Company (*) Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Operating Leases Operating lease ROU assets, net $ 1,907 $ 152 $ 1,492 $ 7 $ 370 $ 95 Operating lease obligations - current $ 241 $ 48 $ 140 $ 2 $ 22 $ 15 Operating lease obligations - non current 1,733 137 1,377 5 373 79 Total operating lease obligations $ 1,974 $ 185 $ 1,517 $ 7 $ 395 $ 94 Finance Leases Finance lease ROU assets, net $ 237 $ 5 $ 142 $ — $ — $ — Finance lease obligations - current $ 24 $ 1 $ 10 $ — $ — $ — Finance lease obligations - noncurrent 220 4 159 — — — Total finance lease obligations $ 244 $ 5 $ 169 $ — $ — $ — (*) Includes operating lease ROU assets, net and operating lease obligations classified as held for sale. Lease costs for the three and six months ended June 30, 2019 , which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) For the Three Months Ended June 30, 2019 Lease cost Operating lease cost $ 77 $ 13 $ 50 $ 1 $ 7 $ 5 Finance lease cost: Amortization of ROU assets 7 — 4 — — — Interest on lease obligations 3 — 4 — — — Total finance lease cost 10 — 8 — — — Short-term lease costs 13 6 6 — — — Variable lease cost 29 1 25 — 1 — Sublease income — — — — — — Total lease cost $ 129 $ 20 $ 89 $ 1 $ 8 $ 5 For the Six Months Ended June 30, 2019 Lease cost Operating lease cost $ 147 $ 20 $ 99 $ 1 $ 14 $ 9 Finance lease cost: Amortization of ROU assets 14 — 7 — — — Interest on lease obligations 6 — 9 — — — Total finance lease cost 20 — 16 — — — Short-term lease costs 30 11 12 — — — Variable lease cost 48 1 41 — 3 — Sublease income — — — — — — Total lease cost $ 245 $ 32 $ 168 $ 1 $ 17 $ 9 Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: For the Six Months Ended June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 129 $ 20 $ 75 $ 1 $ 12 $ 9 Operating cash flows from finance leases 2 — 10 — — — Financing cash flows from finance leases 16 — 3 — — — ROU assets obtained in exchange for new operating lease obligations 55 5 13 — — 13 ROU assets obtained in exchange for new finance lease obligations 33 1 28 — — — As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Weighted-average remaining lease term in years: Operating leases 14.0 3.6 10.5 7.0 33.5 9.7 Finance leases 18.3 12.8 11.0 N/A N/A N/A Weighted-average discount rate: Operating leases 4.53 % 3.33 % 4.46 % 4.06 % 5.68 % 3.73 % Finance leases 5.05 % 3.67 % 10.69 % N/A N/A N/A Maturities of lease liabilities are as follows: As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2019 (remaining) $ 178 $ 33 $ 129 $ 1 $ 13 $ 9 2020 295 53 203 2 22 17 2021 279 52 198 1 23 16 2022 268 52 196 1 23 13 2023 204 4 197 1 24 11 Thereafter 1,661 2 990 2 849 49 Total 2,885 196 1,913 8 954 115 Less: Present value discount 911 11 396 1 559 21 Operating lease obligations $ 1,974 $ 185 $ 1,517 $ 7 $ 395 $ 94 Finance leases: 2019 (remaining) $ 16 $ — $ 16 $ — $ — $ — 2020 33 1 28 — — — 2021 27 1 25 — — — 2022 23 1 25 — — — 2023 18 1 25 — — — Thereafter 266 1 165 — — — Total 383 5 284 — — — Less: Present value discount 139 — 115 — — — Finance lease obligations $ 244 $ 5 $ 169 $ — $ — $ — Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis. As of June 30, 2019 , Southern Company and Southern Power have additional operating leases, primarily for land, that have not yet commenced. These operating leases are expected to commence during the remainder of 2019 through 2022, with lease terms of up to 31 years, and have estimated total obligations of $81 million . For additional information on each registrant's operating lease obligations at December 31, 2018, see Note 9 to the financial statements in Item 8 of the Form 10-K. Lessor With the exception of Southern Company Gas, the registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to five years , after which the contracts renew on a month-to-month basis at the customer's option. For Mississippi Power, these arrangements also include tolling arrangements related to electric generating units accounted for as sales-type leases with terms of up to 20 years. For Southern Power, these arrangements consist of PPAs related to electric generating units, including renewable energy facilities, accounted for as operating leases with terms of up to 28 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with terms of up to 15 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 24 years. Lease income for the three and six months ended June 30, 2019 is as follows: Southern Company Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) For the Three Months Ended June 30, 2019 Lease income - interest income on sales-type leases $ 2 $ — $ 2 $ — $ — Lease income - operating leases 67 19 — 39 9 Variable lease income 115 — — 125 — Total lease income $ 184 $ 19 $ 2 $ 164 $ 9 For the Six Months Ended June 30, 2019 Lease income - interest income on sales-type leases $ 5 $ — $ 5 $ — $ — Lease income - operating leases 139 39 — 80 17 Variable lease income 182 — — 198 — Total lease income $ 326 $ 39 $ 5 $ 278 $ 17 No profit or loss was recognized by Mississippi Power upon commencement of a sales-type lease during the first quarter 2019. Lease income for Southern Power is included in wholesale revenues. 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. Scheduled payments to be received under outdoor lighting contracts, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses. The undiscounted cash flows to be received under tolling arrangements accounted for as sales-type leases are as follows: As of June 30, 2019 Southern Company Mississippi Power (in millions) 2019 (remaining) $ 7 $ 7 2020 14 14 2021 14 14 2022 13 13 2023 12 12 Thereafter 135 135 Total undiscounted cash flows $ 195 $ 195 Lease receivable 106 106 Difference between undiscounted cash flows and discounted cash flows $ 89 $ 89 The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases (adjusted for intercompany eliminations) are as follows: As of June 30, 2019 Southern Company Georgia Power Southern Power Southern Company Gas (in millions) 2019 (remaining) $ 75 $ 13 $ 52 $ 17 2020 125 26 65 35 2021 118 18 66 35 2022 109 8 68 34 2023 103 2 69 34 Thereafter 1,142 — 350 497 Total $ 1,672 $ 67 $ 670 $ 652 Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Southern Power allocates revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under outdoor lighting contracts accounted for as operating leases at Alabama Power and Mississippi Power are immaterial.
LEASES	LEASES On January 1, 2019, the registrants adopted the provisions of FASB ASC Topic 842 (as amended), Leases (ASC 842), which require lessees to recognize leases with a term of greater than 12 months on the balance sheet as lease obligations, representing the discounted future fixed payments due, along with right-of-use (ROU) assets that will be amortized over the term of each lease. The registrants elected the transition methodology provided by ASC 842, whereby the applicable requirements are applied on a prospective basis as of the adoption date of January 1, 2019, without restating prior periods. The registrants also elected the package of practical expedients provided by ASC 842 that allows prior determinations of whether existing contracts are, or contain, leases and the classification of existing leases to continue without reassessment. Additionally, the registrants applied the use-of-hindsight practical expedient in determining lease terms as of the date of adoption and elected the practical expedient that allows existing land easements not previously accounted for as leases not to be reassessed. Lessee As lessee, the registrants lease certain electric generating units (including renewable energy facilities), real estate/land, communication towers, railcars, and other equipment and vehicles. The major categories of lease obligations are as follows: As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Electric generating units $ 1,072 $ 150 $ 1,580 $ — $ — $ — Real estate/land 800 4 62 2 395 81 Communication towers 147 1 3 — — 13 Railcars 54 25 27 3 — — Other 145 10 14 2 — — Total $ 2,218 $ 190 $ 1,686 $ 7 $ 395 $ 94 Real estate/land leases primarily consist of commercial real estate leases at Southern Company, Georgia Power, and Southern Company Gas and various land leases primarily associated with renewable energy facilities at Southern Power. The commercial real estate leases have remaining terms of up to 25 years while the land leases have remaining terms of up to 48 years, including renewal periods. Communication towers are leased for the installation of equipment to provide cellular phone service to customers and to support the automated meter infrastructure programs at the traditional electric operating companies. Communication tower leases have terms of up to 10 years with options to renew for periods up to 20 years. While renewal options exist in many of the leases, other than for land leases associated with renewable energy facilities, the expected term used in calculating the lease obligation generally reflects only the noncancelable period of the lease as it is not considered reasonably certain that the lease will be extended. The expected term of land leases associated with renewable energy facilities includes renewal periods reasonably certain of exercise resulting in an expected lease term at least equal to the expected life of the renewable energy facilities. Contracts that Contain a Lease While not specifically structured as a lease, some of the PPAs at Alabama Power and Georgia Power are deemed to represent a lease of the underlying electric generating units when the terms of the PPA convey the right to control the use of the underlying assets. Amounts recorded for leases of electric generating units are generally based on the amount of scheduled capacity payments due over the remaining term of the affiliate PPA, which varies between four and 18 years. Georgia Power has several PPAs with Southern Power that Georgia Power accounts for as leases with a lease obligation of approximately $660 million at June 30, 2019 . The amount paid for energy under these affiliate PPAs reflects a price that would be paid in an arm's-length transaction as those amounts have been reviewed and approved by the Georgia PSC. Short-term Leases Leases with an initial term of 12 months or less are not recorded on the balance sheet; the registrants generally recognize lease expense for these leases on a straight-line basis over the lease term. Residual Value Guarantees Residual value guarantees exist primarily in railcar leases at Alabama Power and Georgia Power and the amounts probable of being paid under those guarantees are included in the lease payments. All such amounts are immaterial as of June 30, 2019 . Lease and Nonlease Components For all asset categories, with the exception of electric generating units, gas pipelines, and real estate leases, the registrants combine lease payments and any nonlease components, such as asset maintenance, for purposes of calculating the lease obligation and the right-of-use asset. Balance sheet amounts recorded for operating and finance leases are as follows: As of June 30, 2019 Southern Company (*) Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Operating Leases Operating lease ROU assets, net $ 1,907 $ 152 $ 1,492 $ 7 $ 370 $ 95 Operating lease obligations - current $ 241 $ 48 $ 140 $ 2 $ 22 $ 15 Operating lease obligations - non current 1,733 137 1,377 5 373 79 Total operating lease obligations $ 1,974 $ 185 $ 1,517 $ 7 $ 395 $ 94 Finance Leases Finance lease ROU assets, net $ 237 $ 5 $ 142 $ — $ — $ — Finance lease obligations - current $ 24 $ 1 $ 10 $ — $ — $ — Finance lease obligations - noncurrent 220 4 159 — — — Total finance lease obligations $ 244 $ 5 $ 169 $ — $ — $ — (*) Includes operating lease ROU assets, net and operating lease obligations classified as held for sale. Lease costs for the three and six months ended June 30, 2019 , which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) For the Three Months Ended June 30, 2019 Lease cost Operating lease cost $ 77 $ 13 $ 50 $ 1 $ 7 $ 5 Finance lease cost: Amortization of ROU assets 7 — 4 — — — Interest on lease obligations 3 — 4 — — — Total finance lease cost 10 — 8 — — — Short-term lease costs 13 6 6 — — — Variable lease cost 29 1 25 — 1 — Sublease income — — — — — — Total lease cost $ 129 $ 20 $ 89 $ 1 $ 8 $ 5 For the Six Months Ended June 30, 2019 Lease cost Operating lease cost $ 147 $ 20 $ 99 $ 1 $ 14 $ 9 Finance lease cost: Amortization of ROU assets 14 — 7 — — — Interest on lease obligations 6 — 9 — — — Total finance lease cost 20 — 16 — — — Short-term lease costs 30 11 12 — — — Variable lease cost 48 1 41 — 3 — Sublease income — — — — — — Total lease cost $ 245 $ 32 $ 168 $ 1 $ 17 $ 9 Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: For the Six Months Ended June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 129 $ 20 $ 75 $ 1 $ 12 $ 9 Operating cash flows from finance leases 2 — 10 — — — Financing cash flows from finance leases 16 — 3 — — — ROU assets obtained in exchange for new operating lease obligations 55 5 13 — — 13 ROU assets obtained in exchange for new finance lease obligations 33 1 28 — — — As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Weighted-average remaining lease term in years: Operating leases 14.0 3.6 10.5 7.0 33.5 9.7 Finance leases 18.3 12.8 11.0 N/A N/A N/A Weighted-average discount rate: Operating leases 4.53 % 3.33 % 4.46 % 4.06 % 5.68 % 3.73 % Finance leases 5.05 % 3.67 % 10.69 % N/A N/A N/A Maturities of lease liabilities are as follows: As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2019 (remaining) $ 178 $ 33 $ 129 $ 1 $ 13 $ 9 2020 295 53 203 2 22 17 2021 279 52 198 1 23 16 2022 268 52 196 1 23 13 2023 204 4 197 1 24 11 Thereafter 1,661 2 990 2 849 49 Total 2,885 196 1,913 8 954 115 Less: Present value discount 911 11 396 1 559 21 Operating lease obligations $ 1,974 $ 185 $ 1,517 $ 7 $ 395 $ 94 Finance leases: 2019 (remaining) $ 16 $ — $ 16 $ — $ — $ — 2020 33 1 28 — — — 2021 27 1 25 — — — 2022 23 1 25 — — — 2023 18 1 25 — — — Thereafter 266 1 165 — — — Total 383 5 284 — — — Less: Present value discount 139 — 115 — — — Finance lease obligations $ 244 $ 5 $ 169 $ — $ — $ — Payments made under PPAs at Georgia Power for energy generated from certain renewable energy facilities accounted for as operating and finance leases are considered variable lease costs and are therefore not reflected in the above maturity analysis. As of June 30, 2019 , Southern Company and Southern Power have additional operating leases, primarily for land, that have not yet commenced. These operating leases are expected to commence during the remainder of 2019 through 2022, with lease terms of up to 31 years, and have estimated total obligations of $81 million . For additional information on each registrant's operating lease obligations at December 31, 2018, see Note 9 to the financial statements in Item 8 of the Form 10-K. Lessor With the exception of Southern Company Gas, the registrants are each considered lessors in various arrangements that have been determined to contain a lease due to the customer's ability to control the use of the underlying asset owned by the applicable registrant. For the traditional electric operating companies, these arrangements consist of outdoor lighting contracts accounted for as operating leases with initial terms of up to five years , after which the contracts renew on a month-to-month basis at the customer's option. For Mississippi Power, these arrangements also include tolling arrangements related to electric generating units accounted for as sales-type leases with terms of up to 20 years. For Southern Power, these arrangements consist of PPAs related to electric generating units, including renewable energy facilities, accounted for as operating leases with terms of up to 28 years. For Southern Company, these arrangements also include PPAs related to fuel cells accounted for as operating leases with terms of up to 15 years. Southern Company Gas is the lessor in operating leases related to gas pipelines with remaining terms of up to 24 years. Lease income for the three and six months ended June 30, 2019 is as follows: Southern Company Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) For the Three Months Ended June 30, 2019 Lease income - interest income on sales-type leases $ 2 $ — $ 2 $ — $ — Lease income - operating leases 67 19 — 39 9 Variable lease income 115 — — 125 — Total lease income $ 184 $ 19 $ 2 $ 164 $ 9 For the Six Months Ended June 30, 2019 Lease income - interest income on sales-type leases $ 5 $ — $ 5 $ — $ — Lease income - operating leases 139 39 — 80 17 Variable lease income 182 — — 198 — Total lease income $ 326 $ 39 $ 5 $ 278 $ 17 No profit or loss was recognized by Mississippi Power upon commencement of a sales-type lease during the first quarter 2019. Lease income for Southern Power is included in wholesale revenues. 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. Scheduled payments to be received under outdoor lighting contracts, tolling arrangements, and PPAs accounted for as leases are presented in the following maturity analyses. The undiscounted cash flows to be received under tolling arrangements accounted for as sales-type leases are as follows: As of June 30, 2019 Southern Company Mississippi Power (in millions) 2019 (remaining) $ 7 $ 7 2020 14 14 2021 14 14 2022 13 13 2023 12 12 Thereafter 135 135 Total undiscounted cash flows $ 195 $ 195 Lease receivable 106 106 Difference between undiscounted cash flows and discounted cash flows $ 89 $ 89 The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases (adjusted for intercompany eliminations) are as follows: As of June 30, 2019 Southern Company Georgia Power Southern Power Southern Company Gas (in millions) 2019 (remaining) $ 75 $ 13 $ 52 $ 17 2020 125 26 65 35 2021 118 18 66 35 2022 109 8 68 34 2023 103 2 69 34 Thereafter 1,142 — 350 497 Total $ 1,672 $ 67 $ 670 $ 652 Southern Power receives payments for renewable energy under PPAs accounted for as operating leases that are considered contingent rents and are therefore not reflected in the table above. Southern Power allocates revenue to the nonlease components of PPAs based on the stand-alone selling price of capacity and energy. The undiscounted cash flows to be received under outdoor lighting contracts accounted for as operating leases at Alabama Power and Mississippi Power are immaterial.

Segment and Related Information

Segment and Related Information	6 Months Ended
	Jun. 30, 2019
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 – Alabama Power, Georgia Power, and Mississippi Power – are vertically integrated utilities providing electric service in three Southeastern states. Southern Power develops, constructs, acquires, owns, and manages power generation assets, including renewable energy projects, and sells electricity at market-based rates in the wholesale market. Southern Company Gas distributes natural gas through its natural gas distribution utilities and is involved in several other complementary businesses including gas pipeline investments, wholesale gas services, and gas marketing 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 $117 million and $204 million for the three and six months ended June 30, 2019 , respectively, and $109 million and $192 million for the three and six months ended June 30, 2018 , respectively. Revenues from sales of natural gas from Southern Company Gas to the traditional electric operating companies were immaterial for both the three and six months ended June 30, 2019 and 2018 . Revenues from sales of natural gas from Southern Company Gas to Southern Power were $16 million and $33 million for the three and six months ended June 30, 2019 , respectively, and $22 million and $58 million for the three and six months ended June 30, 2018 , respectively. The "All Other" column includes the Southern Company parent entity, which does not allocate operating expenses to business segments. Also, this category includes segments below the quantitative threshold for separate disclosure. These segments include providing energy solutions, such as distributed energy infrastructure and energy efficiency products and services, to customers, as well as investments in telecommunications and leveraged lease projects. All other inter-segment revenues are not material. Financial data for business segments and products and services for the three and six months ended June 30, 2019 and 2018 was as follows: Electric Utilities Traditional Electric Operating Companies Southern Power Eliminations Total Southern Company Gas All Other Eliminations Consolidated (in millions) Three Months Ended June 30, 2019 Operating revenues $ 3,899 $ 510 $ (119 ) $ 4,290 $ 689 $ 186 $ (67 ) $ 5,098 Segment net income (loss) (a)(b)(c)(d) 782 174 — 956 106 (154 ) (9 ) 899 Six Months Ended June 30, 2019 Operating revenues $ 7,343 $ 953 $ (211 ) $ 8,085 $ 2,163 $ 368 $ (106 ) $ 10,510 Segment net income (loss) (a)(b)(c)(d) 1,346 230 — 1,576 376 1,041 (11 ) 2,982 At June 30, 2019 Goodwill $ — $ 2 $ — $ 2 $ 5,015 $ 265 $ — $ 5,282 Total assets 78,314 14,518 (783 ) 92,049 20,761 3,343 (1,286 ) 114,867 Three Months Ended June 30, 2018 Operating revenues $ 4,124 $ 555 $ (114 ) $ 4,565 $ 730 $ 381 $ (49 ) $ 5,627 Segment net income (loss) (a)(b)(d) (48 ) 22 — (26 ) (31 ) (100 ) 3 (154 ) Six Months Ended June 30, 2018 Operating revenues $ 8,104 $ 1,064 $ (220 ) $ 8,948 $ 2,369 $ 782 $ (100 ) $ 11,999 Segment net income (loss) (a)(b)(d)(e) 563 143 — 706 248 (174 ) 4 784 At December 31, 2018 Goodwill $ — $ 2 $ — $ 2 $ 5,015 $ 298 $ — $ 5,315 Total assets 79,382 14,883 (306 ) 93,959 21,448 3,285 (1,778 ) 116,914 (a) Attributable to Southern Company. (b) Segment net income (loss) for the traditional electric operating companies includes pre-tax charges for estimated losses on plants under construction of $4 million ( $3 million after tax) and $1.1 billion ( $0.8 billion after tax) for the three months ended June 30, 2019 and 2018 , respectively, and $6 million ( $5 million after tax) and $1.1 billion ( $0.8 billion after tax) for the six months ended June 30, 2019 and 2018 , respectively. See Note 2 to the financial statements in Item 8 of the Form 10-K and Note (B) under "Georgia Power – Nuclear Construction" and " Mississippi Power – Kemper County Energy Facility " for additional information. (c) Segment net income (loss) for the "All Other" column includes the preliminary pre-tax gain associated with the sale of Gulf Power of $2.5 billion ( $1.3 billion after tax) for the six months ended June 30, 2019 , of which $(15) million ( $(11) million after tax) was recorded in the three months ended June 30, 2019 , as well as a goodwill impairment charge of $32 million for the three and six months ended June 30, 2019 in contemplation of the sale of one of PowerSecure's business units. See Note (K) under " Southern Company " for additional information. (d) Segment net income (loss) for Southern Power includes a $23 million pre-tax gain ( $88 million gain after tax) on the sale of Plant Nacogdoches for the three and six months ended June 30, 2019 and a pre-tax impairment charge of $119 million ( $89 million after tax) for the three and six months ended June 30, 2018 related to the sale of Southern Power's Florida Plants. See Note (K) under " Southern Power " and Note 15 to the financial statements in Item 8 of the Form 10-K under "Southern Power – Sale of Natural Gas Plants" for additional information. (e) Segment net income (loss) for Southern Company Gas includes a goodwill impairment charge of $42 million for the six months ended June 30, 2018 related to the sale of Pivotal Home Solutions. See Note 15 to the financial statements in Item 8 of the Form 10-K under "Southern Company Gas" for additional information. Products and Services Electric Utilities' Revenues Retail Wholesale Other Total (in millions) Three Months Ended June 30, 2019 $ 3,540 $ 542 $ 208 $ 4,290 Three Months Ended June 30, 2018 3,740 616 209 4,565 Six Months Ended June 30, 2019 $ 6,623 $ 1,041 $ 421 $ 8,085 Six Months Ended June 30, 2018 7,308 1,239 401 8,948 Southern Company Gas' Revenues Gas (a) Gas (b) Other Total (in millions) Three Months Ended June 30, 2019 $ 563 $ 58 $ 68 $ 689 Three Months Ended June 30, 2018 638 89 3 730 Six Months Ended June 30, 2019 $ 1,724 $ 287 $ 152 $ 2,163 Six Months Ended June 30, 2018 1,838 359 172 2,369 (a) Operating revenues for the three gas distribution operations dispositions were $70 million and $237 million for the three and six months ended June 30, 2018 , respectively. (b) Operating revenues for Pivotal Home Solutions were $24 million and $55 million for the three and six months ended June 30, 2018 , respectively. Southern Company Gas Southern Company Gas manages its business through four reportable segments – gas distribution operations, gas pipeline investments, wholesale gas services, and gas marketing services. The non-reportable segments are combined and presented as all other. 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, two significant pipeline construction projects, 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. Wholesale gas services provides 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 engages 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 Energy Services, LLC. The all other column includes segments below the quantitative threshold for separate disclosure. This includes Southern Company Gas' storage and fuels operations, its investment in Triton through the completion of its sale on May 29, 2019, and other subsidiaries that fall below the quantitative threshold for separate disclosure. See Note (E) under " Southern Company Gas " for additional information and related disclosures. Business segment financial data for the three and six months ended June 30, 2019 and 2018 was as follows: Gas Distribution Operations (a) Gas Pipeline Investments Wholesale Gas Services (b) Gas Marketing Services (c)(d) Total All Other Eliminations Consolidated (in millions) Three Months Ended June 30, 2019 Operating revenues $ 568 $ 8 $ 48 $ 58 $ 682 $ 13 $ (6 ) $ 689 Segment net income (loss) 58 25 23 (3 ) 103 3 — 106 Six Months Ended June 30, 2019 Operating revenues $ 1,740 $ 16 $ 134 $ 287 $ 2,177 $ 24 $ (38 ) $ 2,163 Segment net income (loss) 191 57 70 58 376 — — 376 Total assets at June 30, 2019 17,397 1,768 668 1,527 21,360 10,934 (11,533 ) 20,761 Three Months Ended June 30, 2018 Operating revenues $ 643 $ 8 $ (16 ) $ 89 $ 724 $ 11 $ (5 ) $ 730 Segment net income (loss) 68 21 (21 ) (76 ) (8 ) (23 ) — (31 ) Six Months Ended June 30, 2018 Operating revenues $ 1,856 $ 16 $ 150 $ 359 $ 2,381 $ 26 $ (38 ) $ 2,369 Segment net income (loss) 216 48 83 (63 ) 284 (36 ) — 248 Total assets at December 31, 2018 17,266 1,763 1,302 1,587 21,918 11,112 (11,582 ) 21,448 (a) Operating revenues for the three gas distribution operations dispositions were $70 million and $237 million for the three and six months ended June 30, 2018 , respectively. See Note 15 to the financial statements in Item 8 of the Form 10-K under "Southern Company Gas" for additional information. (b) The revenues for wholesale gas services are 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 June 30, 2019 $ 1,223 $ 63 $ 1,286 $ 1,238 $ 48 Three Months Ended June 30, 2018 1,336 102 1,438 1,454 (16 ) Six Months Ended June 30, 2019 $ 3,148 $ 151 $ 3,299 $ 3,165 $ 134 Six Months Ended June 30, 2018 3,274 269 3,543 3,393 150 (c) Operating revenues for Pivotal Home Solutions were $24 million and $55 million for the three and six months ended June 30, 2018 , respectively. See Note 15 to the financial statements in Item 8 of the Form 10-K under "Southern Company Gas" for additional information on the sale of Pivotal Home Solutions. (d) Segment net income (loss) for gas marketing services includes a loss on disposition of $36 million for the three and six months ended June 30, 2018 and a goodwill impairment charge of $42 million for the six months ended June 30, 2018 related to the sale of Pivotal Home Solutions. See Note 15 to the financial statements in Item 8 of the Form 10-K under "Southern Company Gas" for additional information.

Introduction (Policies)

Introduction (Policies)	6 Months Ended
	Jun. 30, 2019
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 as of December 31, 2018 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 June 30, 2019 and 2018 . 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, 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 results of operations, financial position, or cash flows of any registrant.
Recently Adopted Accounting Standards	In 2016, the FASB issued ASU No. 2016-02, Leases (Topic 842) (ASU 2016-02). ASU 2016-02 requires lessees to recognize on the balance sheet a lease liability and a right-of-use asset for all leases. ASU 2016-02 also changes the recognition, measurement, and presentation of expense associated with leases and provides clarification regarding the identification of certain components of contracts that would represent a lease. The accounting required by lessors is relatively unchanged and there is no change to the accounting for existing leveraged leases. The registrants adopted the new standard effective January 1, 2019. See Note (L) for additional information and related disclosures.
Goodwill and Other Intangible Assets	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.
Restricted Cash	At December 31, 2018, Georgia Power had restricted cash related to the redemption of pollution control revenue bonds, which were redeemed in January 2019. See Note (F) under " Financing Activities " for additional information. At both June 30, 2019 and December 31, 2018 , Southern Company Gas had restricted cash held as collateral for worker's compensation, life insurance, and long-term disability insurance.
Natural Gas For Sale	Southern Company Gas, with the exception of Nicor Gas, carries natural gas inventory 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. Southern Company Gas recorded adjustments of $7 million and $10 million for the three and six months ended June 30, 2019 , respectively, and no material adjustments for the comparable periods in 2018. 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. Nicor Gas had no inventory decrement at June 30, 2019 .
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. Southern Power has contingent payment obligations related to certain acquisitions whereby Southern Power 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 obligation is 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.
Derivatives	Interest Rate Derivatives Southern Company and certain subsidiaries may enter into interest rate derivatives to hedge exposure to changes in interest rates. The derivatives employed as hedging instruments are structured to minimize ineffectiveness. 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. Southern Company, the traditional electric operating companies, Southern Power, and Southern Company Gas 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. Southern Company Gas' wholesale gas operations use various contracts in its commercial activities that generally meet 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 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. Energy-Related Derivatives The traditional electric operating companies, Southern Power, and Southern Company Gas 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 of operating margins 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 the respective fuel cost recovery clauses. • 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. 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. The derivatives employed as hedging instruments are structured to minimize ineffectiveness.

Introduction (Tables)

Introduction (Tables)	6 Months Ended
	Jun. 30, 2019
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Schedule of Goodwill	Goodwill at June 30, 2019 and December 31, 2018 was as follows: At June 30, 2019 At December 31, 2018 (in millions) Southern Company $ 5,282 $ 5,315 Southern Company Gas: Gas distribution operations $ 4,034 $ 4,034 Gas marketing services 981 981 Southern Company Gas total $ 5,015 $ 5,015
Schedule of Other Intangible Assets, Indefinite-Lived	Other intangible assets were as follows: At June 30, 2019 At December 31, 2018 Gross Carrying Amount Accumulated Amortization Other Intangible Assets, Net Gross Carrying Amount Accumulated Amortization Other (in millions) (in millions) Southern Company Other intangible assets subject to amortization: Customer relationships $ 211 $ (105 ) $ 106 $ 223 $ (94 ) $ 129 Trade names 70 (23 ) 47 70 (21 ) 49 Storage and transportation contracts 64 (58 ) 6 64 (54 ) 10 PPA fair value adjustments 371 (60 ) 311 405 (61 ) 344 Other 12 (7 ) 5 11 (5 ) 6 Total other intangible assets subject to amortization $ 728 $ (253 ) $ 475 $ 773 $ (235 ) $ 538 Other intangible assets not subject to amortization: Federal Communications Commission licenses 75 — 75 75 — 75 Total other intangible assets $ 803 $ (253 ) $ 550 $ 848 $ (235 ) $ 613 Southern Power Other intangible assets subject to amortization: PPA fair value adjustments $ 371 $ (60 ) $ 311 $ 405 $ (61 ) $ 344 Southern Company Gas Other intangible assets subject to amortization: Gas marketing services Customer relationships $ 156 $ (95 ) $ 61 $ 156 $ (84 ) $ 72 Trade names 26 (8 ) 18 26 (7 ) 19 Wholesale gas services Storage and transportation contracts 64 (58 ) 6 64 (54 ) 10 Total other intangible assets subject to amortization $ 246 $ (161 ) $ 85 $ 246 $ (145 ) $ 101
Schedule of Other Intangible Assets, Finite-Lived	Other intangible assets were as follows: At June 30, 2019 At December 31, 2018 Gross Carrying Amount Accumulated Amortization Other Intangible Assets, Net Gross Carrying Amount Accumulated Amortization Other (in millions) (in millions) Southern Company Other intangible assets subject to amortization: Customer relationships $ 211 $ (105 ) $ 106 $ 223 $ (94 ) $ 129 Trade names 70 (23 ) 47 70 (21 ) 49 Storage and transportation contracts 64 (58 ) 6 64 (54 ) 10 PPA fair value adjustments 371 (60 ) 311 405 (61 ) 344 Other 12 (7 ) 5 11 (5 ) 6 Total other intangible assets subject to amortization $ 728 $ (253 ) $ 475 $ 773 $ (235 ) $ 538 Other intangible assets not subject to amortization: Federal Communications Commission licenses 75 — 75 75 — 75 Total other intangible assets $ 803 $ (253 ) $ 550 $ 848 $ (235 ) $ 613 Southern Power Other intangible assets subject to amortization: PPA fair value adjustments $ 371 $ (60 ) $ 311 $ 405 $ (61 ) $ 344 Southern Company Gas Other intangible assets subject to amortization: Gas marketing services Customer relationships $ 156 $ (95 ) $ 61 $ 156 $ (84 ) $ 72 Trade names 26 (8 ) 18 26 (7 ) 19 Wholesale gas services Storage and transportation contracts 64 (58 ) 6 64 (54 ) 10 Total other intangible assets subject to amortization $ 246 $ (161 ) $ 85 $ 246 $ (145 ) $ 101
Finite-lived Intangible Assets Amortization Expense	Amortization associated with other intangible assets was as follows: Three Months Ended Six Months Ended June 30, 2019 (in millions) Southern Company $ 15 $ 32 Southern Power (a) $ 4 $ 10 Southern Company Gas Gas marketing services (b) $ 6 $ 12 Wholesale gas services (a) 2 4 Southern Company Gas total $ 8 $ 16 (a) Recorded as a reduction to operating revenues. (b) Included in depreciation and amortization.
Restrictions on Cash and Cash Equivalents	The following tables provide a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed balance sheets that total to the amounts shown in the condensed statements of cash flows for the registrants that had restricted cash at June 30, 2019 and/or December 31, 2018 : Southern Company Southern Company Gas (in millions) At June 30, 2019 Cash and cash equivalents $ 1,383 $ 56 Restricted cash: Other accounts and notes receivable 4 4 Total cash, cash equivalents, and restricted cash $ 1,386 (*) $ 60 (*) Total does not add due to rounding. Southern Company Georgia Power Southern Company Gas (in millions) At December 31, 2018 Cash and cash equivalents $ 1,396 $ 4 $ 64 Cash and cash equivalents held for sale 9 — — Restricted cash: Restricted cash — 108 — Other accounts and notes receivable 114 — 6 Total cash, cash equivalents, and restricted cash $ 1,519 $ 112 $ 70
Schedule of Cash and Cash Equivalents	The following tables provide a reconciliation of cash, cash equivalents, and restricted cash reported within the condensed balance sheets that total to the amounts shown in the condensed statements of cash flows for the registrants that had restricted cash at June 30, 2019 and/or December 31, 2018 : Southern Company Southern Company Gas (in millions) At June 30, 2019 Cash and cash equivalents $ 1,383 $ 56 Restricted cash: Other accounts and notes receivable 4 4 Total cash, cash equivalents, and restricted cash $ 1,386 (*) $ 60 (*) Total does not add due to rounding. Southern Company Georgia Power Southern Company Gas (in millions) At December 31, 2018 Cash and cash equivalents $ 1,396 $ 4 $ 64 Cash and cash equivalents held for sale 9 — — Restricted cash: Restricted cash — 108 — Other accounts and notes receivable 114 — 6 Total cash, cash equivalents, and restricted cash $ 1,519 $ 112 $ 70
Details of AROs included in the balance sheets	Details of the AROs included in the condensed balance sheets of Southern Company, Alabama Power, and Mississippi Power at June 30, 2019 are shown in the following table. There were no material changes in the AROs of Georgia Power or Southern Power during the first six months of 2019. Southern Company Alabama Power Mississippi Power (in millions) Balance at December 31, 2018 $ 9,394 $ 3,210 $ 160 Liabilities incurred 6 — — Liabilities settled (142 ) (43 ) (17 ) Accretion 197 70 2 Cash flow revisions 452 308 59 Balance at June 30, 2019 $ 9,907 $ 3,545 $ 204

Regulatory Matters (Tables)

Regulatory Matters (Tables)	6 Months Ended
	Jun. 30, 2019
Regulated Operations [Abstract]
Cost Recovery Clauses	The recovery balances for certain of Alabama Power's, Georgia Power's, and Mississippi Power's regulatory clauses at June 30, 2019 and December 31, 2018 were as follows: Regulatory Clause Balance Sheet Line Item June 30, December 31, (in millions) Alabama Power Rate CNP Compliance Deferred under recovered regulatory clause revenues $ — $ 42 Customer accounts receivable 10 — Rate CNP PPA Deferred under recovered regulatory clause revenues 25 25 Retail Energy Cost Recovery (*) Deferred under recovered regulatory clause revenues — 109 Customer accounts receivable 8 — Natural Disaster Reserve Other regulatory liabilities, deferred 19 20 Georgia Power Fuel Cost Recovery Receivables – under recovered fuel clause revenues $ 69 $ 115 Mississippi Power Fuel Cost Recovery Over recovered regulatory clause liabilities $ 9 $ 8 (*) In accordance with an accounting order issued on February 5, 2019 by the Alabama PSC, Alabama Power utilized $75 million of the 2018 Rate RSE refund liability to reduce the Rate ECR under recovered balance. See Note 2 to the financial statements under "Alabama Power – Rate ECR" in Item 8 of the Form 10-K for additional information.
Requested Recovery of Proposed Increases	Georgia Power has requested recovery of the proposed increases through its existing base rate tariffs as follows: Tariff 2020 2021 2022 (in millions) Traditional base: Levelized $ 209 $ — $ — CCR AROs 158 140 227 Environmental Compliance Cost Recovery 165 — — Demand-Side Management 14 2 1 Municipal Franchise Fee 17 3 5 Total (*) $ 563 $ 145 $ 234 (*) Totals may not add due to rounding.
Cost and Schedule	Georgia Power's approximate proportionate share of the remaining estimated capital cost to complete Plant Vogtle Units 3 and 4 by the expected in-service dates of November 2021 and November 2022, respectively, is as follows: (in billions) Base project capital cost forecast (a)(b) $ 8.0 Construction contingency estimate 0.4 Total project capital cost forecast (a)(b) 8.4 Net investment as of June 30, 2019 (b) (5.2 ) Remaining estimate to complete (a) $ 3.2 (a) Excludes financing costs expected to be capitalized through AFUDC of approximately $315 million . (b) Net of $1.7 billion received from Toshiba under the Guarantee Settlement Agreement and approximately $188 million in related Customer Refunds.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	6 Months Ended
	Jun. 30, 2019
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue	The following tables disaggregate revenue sources for the three and six months ended June 30, 2019 and 2018 : For the Three Months Ended June 30, 2019 For the Three Months Ended June 30, 2018 For the Six Months Ended June 30, 2019 For the Six Months Ended June 30, 2018 (in millions) Southern Company Operating revenues Retail electric revenues (a) Residential $ 1,488 $ 1,579 $ 2,776 $ 3,118 Commercial 1,258 1,315 2,350 2,557 Industrial 763 814 1,440 1,569 Other 31 32 57 64 Natural gas distribution revenues (b) 562 642 1,724 1,865 Alternative revenue programs (c) 1 (4 ) — (27 ) Total retail electric and gas distribution revenues $ 4,103 $ 4,378 $ 8,347 $ 9,146 Wholesale energy revenues (d)(e) 410 464 777 937 Wholesale capacity revenues (e) 132 152 264 302 Other natural gas revenues (f)(g) 126 68 439 476 Other revenues (h) 327 565 683 1,138 Total operating revenues $ 5,098 $ 5,627 $ 10,510 $ 11,999 (a) Retail electric revenues include $8 million , $18 million , $16 million , and $36 million of revenues accounted for as leases for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, and a (net reduction) or net increase of $(14) million , $68 million , $(117) million and $101 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, from certain cost recovery mechanisms that are not accounted for as revenue under ASC 606. (b) Natural gas distribution revenues include $5 million for each of the three months ended June 30, 2019 and 2018 and $8 million for each of the six months ended June 30, 2019 and 2018 of revenues not accounted for under ASC 606. (c) Alternative revenue program revenues are presented net of any previously recognized program amounts billed to customers during the same accounting period. (d) Wholesale energy revenues include $30 million , $61 million , $82 million , and $155 million of revenues accounted for as derivatives for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, primarily related to physical energy sales in the wholesale electricity market. (e) Wholesale energy revenues include $115 million , $118 million , $182 million , and $187 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, and wholesale capacity revenues include $22 million , $31 million , $47 million , and $61 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, related to PPAs accounted for as leases. (f) Other natural gas revenues related to Southern Company Gas' energy and risk management activities are presented net of the related costs of those activities and include gross third-party revenues of $1.2 billion , $1.3 billion , $3.1 billion , and $3.3 billion for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, of which $0.8 billion , $0.7 billion , $2.0 billion , and $1.8 billion , respectively, relates to contracts that are accounted for as derivatives. See Note (M) under " Southern Company Gas " for additional information on the components of wholesale gas services operating revenues. (g) Other natural gas revenues include $10 million and $27 million for the three and six months ended June 30, 2019 , respectively, of revenues not accounted for under ASC 606, including $8 million and $16 million , respectively, of revenues accounted for as leases. (h) Other revenues include $89 million , $89 million , $180 million , and $183 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, of revenues not accounted for under ASC 606, including $28 million , $33 million , $59 million , and $66 million , respectively, accounted for as leases. Alabama Power Georgia Power Mississippi Power (in millions) For the Three Months Ended June 30, 2019 Operating revenues Retail revenues (a)(b) Residential $ 588 $ 831 $ 69 Commercial 418 767 73 Industrial 366 327 70 Other 6 21 3 Total retail electric revenues $ 1,378 $ 1,946 $ 215 Wholesale energy revenues (c) 41 14 93 Wholesale capacity revenues 25 22 1 Other revenues (b)(d) 69 135 4 Total operating revenues $ 1,513 $ 2,117 $ 313 For the Three Months Ended June 30, 2018 Operating revenues Retail revenues (a)(b) Residential $ 557 $ 785 $ 65 Commercial 402 749 68 Industrial 372 335 76 Other 7 20 3 Total retail electric revenues $ 1,338 $ 1,889 $ 212 Wholesale energy revenues (c) 71 26 77 Wholesale capacity revenues 25 13 1 Other revenues (b)(d) 69 120 7 Total operating revenues $ 1,503 $ 2,048 $ 297 (a) Retail revenues at Alabama Power, Georgia Power, and Mississippi Power include a net increase or (net reduction) of $(11) million , $(5) million , and $2 million , respectively, for the three months ended June 30, 2019 and $78 million , $3 million , and $(1) million , respectively, for the three months ended June 30, 2018 related to certain cost recovery mechanisms that are not accounted for as revenue under ASC 606. (b) Retail revenues and other revenues at Georgia Power include $8 million and $11 million , respectively, for the three months ended June 30, 2019 and $18 million and $33 million , respectively, for the three months ended June 30, 2018 of revenues accounted for as leases. (c) Wholesale energy revenues at Alabama Power, Georgia Power, and Mississippi Power include $3 million , $4 million , and $1 million , respectively, for the three months ended June 30, 2019 and $4 million , $5 million , and $1 million , respectively, for the three months ended June 30, 2018 accounted for as derivatives primarily related to physical energy sales in the wholesale electricity market. (d) Other revenues at Alabama Power and Georgia Power include $31 million and $30 million , respectively, for the three months ended June 30, 2019 and $26 million and $26 million , respectively, for the three months ended June 30, 2018 of revenues not accounted for under ASC 606. Alabama Power Georgia Power Mississippi Power (in millions) For the Six Months Ended June 30, 2019 Operating revenues Retail revenues (a)(b) Residential $ 1,128 $ 1,519 $ 129 Commercial 772 1,440 138 Industrial 679 616 145 Other 13 39 6 Total retail electric revenues $ 2,592 $ 3,614 $ 418 Wholesale energy revenues (c) 135 27 170 Wholesale capacity revenues 51 40 2 Other revenues (b)(d) 143 270 10 Total operating revenues $ 2,921 $ 3,951 $ 600 For the Six Months Ended June 30, 2018 Operating revenues Retail revenues (a)(b) Residential $ 1,127 $ 1,529 $ 125 Commercial 774 1,466 130 Industrial 710 650 146 Other 13 43 5 Total retail electric revenues $ 2,624 $ 3,688 $ 406 Wholesale energy revenues (c) 172 66 176 Wholesale capacity revenues 49 27 5 Other revenues (b)(d) 131 227 11 Total operating revenues $ 2,976 $ 4,008 $ 598 (a) Retail revenues at Alabama Power, Georgia Power, and Mississippi Power include a net increase or (net reduction) of $(68) million , $(52) million , and $3 million , respectively, for the six months ended June 30, 2019 and $125 million , $12 million , and $(8) million , respectively, for the six months ended June 30, 2018 related to certain cost recovery mechanisms that are not accounted for as revenue under ASC 606. (b) Retail revenues and other revenues at Georgia Power include $16 million and $23 million , respectively, for the six months ended June 30, 2019 and $36 million and $66 million , respectively, for the six months ended June 30, 2018 of revenues accounted for as leases. (c) Wholesale energy revenues at Alabama Power, Georgia Power, and Mississippi Power include $6 million , $8 million , and $1 million , respectively, for the six months ended June 30, 2019 and $9 million , $13 million , and $2 million , respectively, for the six months ended June 30, 2018 accounted for as derivatives primarily related to physical energy sales in the wholesale electricity market. (d) Other revenues at Alabama Power and Georgia Power include $59 million and $61 million , respectively, for the six months ended June 30, 2019 and $52 million and $53 million , respectively, for the six months ended June 30, 2018 of revenues not accounted for under ASC 606. For the Three Months Ended June 30, 2019 For the Three Months Ended June 30, 2018 For the Six Months Ended June 30, 2019 For the Six Months Ended June 30, 2018 (in millions) Southern Power PPA capacity revenues (a) $ 125 $ 144 $ 252 $ 282 PPA energy revenues (a) 291 302 518 556 Non-PPA revenues (b) 91 106 177 221 Other revenues 3 3 6 5 Total operating revenues $ 510 $ 555 $ 953 $ 1,064 (a) PPA capacity revenues include $39 million , $47 million , $80 million , and $94 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, and PPA energy revenues include $125 million , $127 million , $198 million , and $203 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, related to PPAs accounted for as leases. (b) Non-PPA revenues include $22 million , $50 million , $67 million , and $129 million for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, of revenues from short-term sales related to physical energy sales from uncovered capacity in the wholesale electricity market. For the Three Months Ended June 30, 2019 For the Three Months Ended June 30, 2018 For the Six Months Ended June 30, 2019 For the Six Months Ended June 30, 2018 (in millions) Southern Company Gas Operating revenues Natural gas distribution revenues (a) Residential $ 229 $ 273 $ 830 $ 933 Commercial 65 76 235 268 Transportation 213 228 469 505 Industrial 5 7 22 24 Other 50 58 168 135 Alternative revenue programs (b) 1 (4 ) — (27 ) Total natural gas distribution revenues $ 563 $ 638 $ 1,724 $ 1,838 Gas pipeline investments (c) 8 8 16 16 Wholesale gas services (d) 48 (15 ) 114 131 Gas marketing services (e) 58 89 287 359 Other revenues 12 10 22 25 Total operating revenues $ 689 $ 730 $ 2,163 $ 2,369 (a) Natural gas distribution revenues include $5 million for each of the three months ended June 30, 2019 and 2018 and $8 million for each of the six months ended June 30, 2019 and 2018 of revenues not accounted for under ASC 606. (b) Alternative revenue program revenues are presented net of any previously recognized program amounts billed to customers during the same accounting period. (c) Revenues from gas pipeline investments include $8 million and $16 million for the three and six months ended June 30, 2019 , respectively, accounted for as leases. (d) Wholesale gas services revenues are presented net of the related costs associated with its energy trading and risk management activities. Operating revenues, as presented, include gross third-party revenues of $1.2 billion , $1.3 billion , $3.1 billion , and $3.3 billion for the three months ended June 30, 2019 and 2018 and the six months ended June 30, 2019 and 2018 , respectively, of which $0.8 billion , $0.7 billion , $2.0 billion , and $1.8 billion , respectively, relates to contracts accounted for as derivatives. See Note (M) under " Southern Company Gas " for additional information on the components of wholesale gas services operating revenues. (e) Gas marketing services include $2 million for the three months ended June 30, 2019 and $11 million and $4 million for the six months ended June 30, 2019 and 2018 , respectively, of revenues not accounted for under ASC 606.
Contract with Customer, Asset and Liability and Revenue Recognized	The following table reflects revenue from contracts with customers recognized in the three and six months ended June 30, 2019 included in the contract liability at December 31, 2018 : Three Months Ended Six Months Ended (in millions) Southern Company $ 11 $ 27 Southern Power 1 11 The following table reflects the closing balances of receivables, contract assets, and contract liabilities related to revenues from contracts with customers as of June 30, 2019 and December 31, 2018 : Receivables Contract Assets Contract Liabilities June 30, 2019 December 31, 2018 June 30, 2019 December 31, 2018 June 30, 2019 December 31, 2018 (in millions) Southern Company (*) $ 2,343 $ 2,630 $ 70 $ 102 $ 58 $ 32 Alabama Power 629 520 — — 10 12 Georgia Power 807 721 30 58 26 7 Mississippi Power 93 100 — — 7 — Southern Power 119 118 — — 1 11 Southern Company Gas 550 952 — — 1 2 (*) Includes amounts related to held for sale investments.
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction	Registrants with revenues from contracts with customers related to these performance obligations remaining at June 30, 2019 expect the revenues to be recognized as follows: 2019 (remaining) 2020 2021 2022 2023 Thereafter (in millions) Southern Company $ 282 $ 490 $ 320 $ 311 $ 302 $ 2,230 Alabama Power 11 23 27 23 22 140 Georgia Power 27 51 44 31 31 83 Southern Power 169 295 270 276 269 2,154

Consolidated Entities and Equ_2

Consolidated Entities and Equity Method Investments (Tables)	6 Months Ended
	Jun. 30, 2019
Regulated Operations [Abstract]
Equity Method Investments	Selected financial information of SNG for the three and six months ended June 30, 2019 and 2018 is as follows: Income Statement Information Three Months Ended June 30, 2019 Three Months Ended June 30, 2018 Six Months Ended June 30, 2019 Six Months Ended June 30, 2018 (in millions) Revenues $ 155 $ 146 $ 321 $ 306 Operating income 86 60 192 159 Net income 64 54 148 132 The carrying amounts of Southern Company Gas' equity method investments as of June 30, 2019 and December 31, 2018 and related income from those investments for the three - and six -month periods ended June 30, 2019 and 2018 were as follows: Investment Balance June 30, 2019 December 31, 2018 (in millions) SNG $ 1,243 $ 1,261 Atlantic Coast Pipeline 101 83 PennEast Pipeline 77 71 Other (*) 88 123 Total $ 1,509 $ 1,538 (*) Decrease primarily relates to the sale of Triton.
Schedule of Other Nonoperating Income, by Component	Earnings from Equity Method Investments Three Months Ended June 30, 2019 Three Months Ended June 30, 2018 Six Months Ended June 30, 2019 Six Months Ended June 30, 2018 (in millions) SNG $ 32 $ 27 $ 74 $ 66 Atlantic Coast Pipeline 3 1 6 3 PennEast Pipeline 1 1 3 2 Other (*) (5 ) 2 (3 ) 3 Total $ 31 $ 31 $ 80 $ 74 (*) Decrease primarily relates to the sale of Triton.

Financing (Tables)

Financing (Tables)	6 Months Ended
	Jun. 30, 2019
Debt Disclosure [Abstract]
Credit Arrangements by Company	The following table outlines the committed credit arrangements by company as of June 30, 2019 : Expires Company 2019 2020 2022 2024 Total Unused Due within One Year (in millions) Southern Company (a) $ — $ — $ — $ 2,000 $ 2,000 $ 1,999 $ — Alabama Power 3 500 — 800 1,303 1,303 3 Georgia Power — — — 1,750 1,750 1,736 — Mississippi Power — — 150 — 150 150 — Southern Power (b) — — — 600 600 561 — Southern Company Gas (c) — — — 1,750 1,750 1,745 — Other — 30 — — 30 30 30 Southern Company Consolidated $ 3 $ 530 $ 150 $ 6,900 $ 7,583 $ 7,524 $ 33 (a) Represents the Southern Company parent entity. (b) Does not include Southern Power Company's $120 million continuing letter of credit facility for standby letters of credit expiring in 2021, of which $30 million was unused at June 30, 2019 . Southern Power's subsidiaries are not parties to its bank credit arrangement. (c) Southern Company Gas, as the parent entity, guarantees the obligations of Southern Company Gas Capital, which is the borrower of $1.25 billion of this arrangement. Southern Company Gas' committed credit arrangement also includes $500 million for which Nicor Gas is the borrower and which is restricted for working capital needs of Nicor Gas. Pursuant to this multi-year credit arrangement, the allocations between Southern Company Gas Capital and Nicor Gas may be adjusted.
Schedule of Long-term Debt Financing Activities	The following table outlines the long-term debt financing activities for Southern Company and its subsidiaries for the first six months of 2019 : Company Senior Note Maturities, Redemptions, and Repurchases Revenue Bond Issuances and Reofferings of Purchased Bonds Revenue Bond and Other Long-Term Debt Issuances Other Long-Term Debt Redemptions and Maturities (a) (in millions) Southern Company (b) $ 2,100 $ — $ — $ — $ — Alabama Power 200 — — — — Georgia Power — 513 223 835 3 Mississippi Power — 43 — — — Other — — 25 — 9 Southern Company Consolidated $ 2,300 $ 556 $ 248 $ 835 $ 12 (a) Includes reductions in finance lease obligations resulting from cash payments under finance leases. (b) Represents the Southern Company parent entity.
Shares Used to Compute Diluted Earnings Per Share	Shares used to compute diluted earnings per share were as follows: Three Months Ended June 30, 2019 Three Months Ended June 30, 2018 Six Months Ended June 30, 2019 Six Months Ended June 30, 2018 (in millions) As reported shares 1,044 1,014 1,041 1,012 Effect of stock-based compensation 8 — 8 5 Diluted shares 1,052 1,014 1,049 1,017

Retirement Benefits (Tables)

Retirement Benefits (Tables)	6 Months Ended
	Jun. 30, 2019
Retirement Benefits [Abstract]
Pension Plans and Postretirement Plans	Components of the net periodic benefit costs for the three and six months ended June 30, 2019 and 2018 are presented in the following tables. Three Months Ended June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Pension Plans Service cost $ 73 $ 17 $ 18 $ 3 $ 1 $ 6 Interest cost 123 29 39 5 2 9 Expected return on plan assets (221 ) (52 ) (73 ) (10 ) (3 ) (15 ) Amortization: Prior service costs 1 1 1 — — — Regulatory asset — — — — — 4 Net (gain)/loss 30 9 11 2 — — Net periodic pension cost (income) $ 6 $ 4 $ (4 ) $ — $ — $ 4 Postretirement Benefits Service cost $ 4 $ 1 $ 1 $ — $ — $ — Interest cost 17 4 6 1 — 3 Expected return on plan assets (17 ) (7 ) (6 ) (1 ) — (1 ) Amortization: Prior service costs 1 1 — — — — Regulatory asset — — — — — 1 Net (gain)/loss — — — — — (1 ) Net periodic postretirement benefit cost $ 5 $ (1 ) $ 1 $ — $ — $ 2 Six Months Ended June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Pension Plans Service cost $ 146 $ 34 $ 37 $ 6 $ 3 $ 12 Interest cost 246 57 78 11 3 18 Expected return on plan assets (442 ) (103 ) (146 ) (20 ) (5 ) (30 ) Amortization: Prior service costs 1 1 1 — — (1 ) Regulatory asset — — — — — 7 Net (gain)/loss 60 18 22 3 — 1 Net periodic pension cost (income) $ 11 $ 7 $ (8 ) $ — $ 1 $ 7 Postretirement Benefits Service cost $ 9 $ 2 $ 2 $ — $ — $ 1 Interest cost 34 8 13 2 — 5 Expected return on plan assets (33 ) (13 ) (12 ) (1 ) — (3 ) Amortization: Prior service costs 2 2 — — — — Regulatory asset — — — — — 3 Net (gain)/loss (1 ) — — — — (2 ) Net periodic postretirement benefit cost $ 11 $ (1 ) $ 3 $ 1 $ — $ 4 Three Months Ended June 30, 2018 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Pension Plans Service cost $ 89 $ 20 $ 21 $ 4 $ 2 $ 8 Interest cost 116 25 35 5 2 9 Expected return on plan assets (235 ) (53 ) (74 ) (10 ) (2 ) (17 ) Amortization: Prior service costs 1 1 1 — — — Regulatory asset — — — — — 4 Net (gain)/loss 54 13 17 2 — 3 Net periodic pension cost (income) $ 25 $ 6 $ — $ 1 $ 2 $ 7 Postretirement Benefits Service cost $ 6 $ 2 $ 1 $ 1 $ — $ — Interest cost 18 4 7 1 — 3 Expected return on plan assets (17 ) (7 ) (7 ) (1 ) — (2 ) Amortization: Prior service costs 1 1 1 — — — Regulatory asset — — — — — 2 Net (gain)/loss 4 1 2 — — — Net periodic postretirement benefit cost $ 12 $ 1 $ 4 $ 1 $ — $ 3 Six Months Ended June 30, 2018 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Pension Plans Service cost $ 179 $ 39 $ 43 $ 8 $ 4 $ 16 Interest cost 232 50 70 10 3 19 Expected return on plan assets (471 ) (104 ) (148 ) (20 ) (5 ) (35 ) Amortization: Prior service costs 2 1 1 — — (1 ) Regulatory asset — — — — — 7 Net (gain)/loss 107 27 34 5 1 6 Net periodic pension cost (income) $ 49 $ 13 $ — $ 3 $ 3 $ 12 Postretirement Benefits Service cost $ 12 $ 3 $ 3 $ 1 $ — $ 1 Interest cost 37 8 14 2 — 5 Expected return on plan assets (34 ) (13 ) (13 ) (1 ) — (4 ) Amortization: Prior service costs 3 2 1 — — — Regulatory asset — — — — — 3 Net (gain)/loss 7 1 4 — — — Net periodic postretirement benefit cost $ 25 $ 1 $ 9 $ 2 $ — $ 5

Fair Value Measurements (Tables

Fair Value Measurements (Tables)	6 Months Ended
	Jun. 30, 2019
Fair Value Disclosures [Abstract]
Assets and Liabilities Measured at Fair Value on a Recurring Basis	As of June 30, 2019 , 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: As of June 30, 2019: Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Net Asset Value as a Practical Expedient (NAV) Total (in millions) Southern Company Assets: Energy-related derivatives (a) $ 270 $ 177 $ 12 $ — $ 459 Foreign currency derivatives — 60 — — 60 Investments in trusts: (b)(c) Domestic equity 703 124 — — 827 Foreign equity 62 206 — — 268 U.S. Treasury and government agency securities — 307 — — 307 Municipal bonds — 72 — — 72 Pooled funds – fixed income — 16 — — 16 Corporate bonds 23 299 — — 322 Mortgage and asset backed securities — 74 — — 74 Private equity — — — 54 54 Cash and cash equivalents 1 — — — 1 Other 27 2 — — 29 Cash equivalents 841 5 — — 846 Other investments 9 17 — — 26 Total $ 1,936 $ 1,359 $ 12 $ 54 $ 3,361 Liabilities: Energy-related derivatives (a) $ 405 $ 189 $ 22 $ — $ 616 Interest rate derivatives — 52 — — 52 Foreign currency derivatives — 23 — — 23 Contingent consideration — — 21 — 21 Total $ 405 $ 264 $ 43 $ — $ 712 Fair Value Measurements Using: As of June 30, 2019: Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Net Asset Value as a Practical Expedient (NAV) Total (in millions) Alabama Power Assets: Energy-related derivatives $ — $ 6 $ — $ — $ 6 Nuclear decommissioning trusts: (b) Domestic equity 456 113 — — 569 Foreign equity 62 60 — — 122 U.S. Treasury and government agency securities — 21 — — 21 Municipal bonds — 1 — — 1 Corporate bonds 23 141 — — 164 Mortgage and asset backed securities — 25 — — 25 Private equity — — — 54 54 Other 7 — — — 7 Cash equivalents 430 5 — — 435 Other investments — 17 — — 17 Total $ 978 $ 389 $ — $ 54 $ 1,421 Liabilities: Energy-related derivatives $ — $ 18 $ — $ — $ 18 Georgia Power Assets: Energy-related derivatives $ — $ 6 $ — $ — $ 6 Nuclear decommissioning trusts: (b)(c) Domestic equity 247 1 — — 248 Foreign equity — 143 — — 143 U.S. Treasury and government agency securities — 286 — — 286 Municipal bonds — 71 — — 71 Corporate bonds — 158 — — 158 Mortgage and asset backed securities — 50 — — 50 Other 20 2 — — 22 Total $ 267 $ 717 $ — $ — $ 984 Liabilities: Energy-related derivatives $ — $ 43 $ — $ — $ 43 Interest rate derivatives — 37 — — 37 Total $ — $ 80 $ — $ — $ 80 Fair Value Measurements Using: As of June 30, 2019: Quoted Prices in Active Markets for Identical Assets (Level 1) Significant Other Observable Inputs (Level 2) Significant Unobservable Inputs (Level 3) Net Asset Value as a Practical Expedient (NAV) Total (in millions) Mississippi Power Assets: Energy-related derivatives $ — $ 3 $ — $ — $ 3 Cash equivalents 170 — — — 170 Total $ 170 $ 3 $ — $ — $ 173 Liabilities: Energy-related derivatives $ — $ 19 $ — $ — $ 19 Southern Power Assets: Energy-related derivatives $ — $ 2 $ — $ — $ 2 Foreign currency derivatives — 60 — — 60 Cash equivalents 177 — — — 177 Total $ 177 $ 62 $ — $ — $ 239 Liabilities: Energy-related derivatives $ — $ 4 $ — $ — $ 4 Foreign currency derivatives — 23 — — 23 Contingent consideration — — 21 — 21 Total $ — $ 27 $ 21 $ — $ 48 Southern Company Gas Assets: Energy-related derivatives (a) $ 270 $ 160 $ 12 $ — $ 442 Non-qualified deferred compensation trusts: Domestic equity — 10 — — 10 Foreign equity — 4 — — 4 Pooled funds – fixed income — 16 — — 16 Cash equivalents 1 — — — 1 Total $ 271 $ 190 $ 12 $ — $ 473 Liabilities: Energy-related derivatives (a) $ 405 $ 105 $ 22 $ — $ 532 (a) Energy-related derivatives exclude cash collateral of $178 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. As of June 30, 2019 , approximately $30 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 and six months ended June 30, 2019 and 2018. The changes were recorded as a change to the regulatory assets and liabilities related to AROs for Georgia Power and Alabama Power, respectively. Three Months Ended June 30, 2019 Three Months Ended June 30, 2018 Six Months Ended June 30, 2019 Six Months Ended June 30, 2018 (in millions) Southern Company $ 75 $ 14 $ 227 $ 4 Alabama Power 38 15 125 10 Georgia Power 37 (1 ) 102 (6 )
Financial Instruments for Which Carrying Amount Did Not Equal Fair Value	As of June 30, 2019 , other financial instruments for which the carrying amount did not equal fair value were as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (*) (in millions) Long-term debt, including securities due within one year: Carrying amount $ 42,596 $ 7,922 $ 10,969 $ 1,618 $ 5,011 $ 5,916 Fair value 45,394 8,717 11,749 1,657 5,261 6,420 (*) 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 lives of the respective bonds.
Fair Value of Commodity Derivative Contracts that Include a Significant Unobservable Component	The following table includes transfers to Level 3, which represent the fair value of Southern Company Gas' commodity derivative contracts that include a significant unobservable component for the first time during the period. Three Months Ended June 30, 2019 Six Months Ended June 30, 2019 (in millions) Beginning balance $ (19 ) $ — Transfers to Level 3 (3 ) (33 ) Changes in fair value 12 23 Ending balance $ (10 ) $ (10 )

Derivatives (Tables)

Derivatives (Tables)	6 Months Ended
	Jun. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Energy-Related Derivatives	At June 30, 2019 , 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 Purchased mmBtu Longest Hedge Date Longest Non-Hedge Date (in millions) Southern Company (*) 536 2023 2029 Alabama Power 88 2022 — Georgia Power 200 2022 — Mississippi Power 101 2023 — Southern Power 8 2020 — Southern Company Gas (*) 139 2021 2029 (*) 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 4.0 billion mmBtu and short natural gas positions of 3.9 billion mmBtu as of June 30, 2019 , which is also included in Southern Company's total volume.
Schedule of Interest Rate Derivatives	At June 30, 2019 , the following interest rate derivatives were outstanding: Notional Amount Interest Rate Received Weighted Average Interest Rate Paid Hedge Maturity Date Fair Value Gain (Loss) at June 30, 2019 (in millions) (in millions) Cash Flow Hedges of Forecasted Debt Georgia Power $ 250 3-month LIBOR 2.23% March 2025 $ (6 ) Georgia Power 250 3-month LIBOR 2.39% September 2029 (10 ) Georgia Power 250 3-month LIBOR 2.40% March 2030 (9 ) Georgia Power 250 3-month LIBOR 2.48% February 2044 (12 ) Fair Value Hedges of Existing Debt Southern Company (*) 300 2.75% 3-month LIBOR+0.92% June 2020 (1 ) Southern Company (*) 1,500 2.35% 1-month LIBOR+0.87% July 2021 (14 ) Georgia Power 200 4.25% 3-month LIBOR+2.46% December 2019 (1 ) Southern Company Consolidated $ 3,000 $ (53 ) (*) Represents the Southern Company parent entity.
Schedule of Foreign Currency Derivatives	At June 30, 2019 , the following foreign currency derivatives were outstanding: Pay Notional Pay Rate Receive Notional Receive Rate Hedge Fair Value Gain (Loss) at June 30, 2019 (in millions) (in millions) (in millions) Cash Flow Hedges of Existing Debt Southern Power $ 677 2.95% € 600 1.00% June 2022 $ 14 Southern Power 564 3.78% 500 1.85% June 2026 23 Total $ 1,241 € 1,100 $ 37
Fair Value of Energy-Related Derivatives and Interest Rate Derivatives	The fair value of energy-related derivatives, interest rate derivatives, and foreign currency derivatives was reflected in the balance sheets as follows: As of June 30, 2019 As of December 31, 2018 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: Other current assets/Other current liabilities $ 7 $ 57 $ 8 $ 23 Other deferred charges and assets/Other deferred credits and liabilities 9 34 9 26 Assets held for sale, current/Liabilities held for sale, current — — — 6 Total derivatives designated as hedging instruments for regulatory purposes $ 16 $ 91 $ 17 $ 55 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Other current assets/Other current liabilities $ 1 $ 7 $ 3 $ 7 Other deferred charges and assets/Other deferred credits and liabilities — 1 1 2 Interest rate derivatives: Other current assets/Other current liabilities — 50 — 19 Other deferred charges and assets/Other deferred credits and liabilities — 2 — 30 Foreign currency derivatives: Other current assets/Other current liabilities — 23 — 23 Other deferred charges and assets/Other deferred credits and liabilities 60 — 75 — Total derivatives designated as hedging instruments in cash flow and fair value hedges $ 61 $ 83 $ 79 $ 81 Derivatives not designated as hedging instruments Energy-related derivatives: Other current assets/Other current liabilities $ 286 $ 298 $ 561 $ 575 Other deferred charges and assets/Other deferred credits and liabilities 156 219 180 325 Total derivatives not designated as hedging instruments $ 442 $ 517 $ 741 $ 900 Gross amounts recognized $ 519 $ 691 $ 837 $ 1,036 Gross amounts offset (a) $ (328 ) $ (506 ) $ (524 ) $ (801 ) Net amounts recognized in the Balance Sheets (b) $ 191 $ 185 $ 313 $ 235 As of June 30, 2019 As of December 31, 2018 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 $ 4 $ 11 $ 3 $ 4 Other deferred charges and assets/Other deferred credits and liabilities 2 7 3 6 Total derivatives designated as hedging instruments for regulatory purposes $ 6 $ 18 $ 6 $ 10 Gross amounts recognized $ 6 $ 18 $ 6 $ 10 Gross amounts offset $ (3 ) $ (3 ) $ (4 ) $ (4 ) Net amounts recognized in the Balance Sheets $ 3 $ 15 $ 2 $ 6 Georgia Power Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Other current assets/Other current liabilities $ 1 $ 26 $ 2 $ 8 Other deferred charges and assets/Other deferred credits and liabilities 5 17 4 13 Total derivatives designated as hedging instruments for regulatory purposes $ 6 $ 43 $ 6 $ 21 Derivatives designated as hedging instruments in cash flow and fair value hedges Interest rate derivatives: Other current assets/Other current liabilities $ — $ 37 $ — $ 2 Total derivatives designated as hedging instruments in cash flow and fair value hedges $ — $ 37 $ — $ 2 Gross amounts recognized $ 6 $ 80 $ 6 $ 23 Gross amounts offset $ (6 ) $ (6 ) $ (6 ) $ (6 ) Net amounts recognized in the Balance Sheets $ — $ 74 $ — $ 17 As of June 30, 2019 As of December 31, 2018 Derivative Category and Balance Sheet Location Assets Liabilities Assets Liabilities (in millions) (in millions) Mississippi Power Derivatives designated as hedging instruments for regulatory purposes Energy-related derivatives: Other current assets/Other current liabilities $ 1 $ 10 $ 1 $ 3 Other deferred charges and assets/Other deferred credits and liabilities 2 9 2 6 Total derivatives designated as hedging instruments for regulatory purposes $ 3 $ 19 $ 3 $ 9 Gross amounts recognized $ 3 $ 19 $ 3 $ 9 Gross amounts offset $ (3 ) $ (3 ) $ (2 ) $ (2 ) Net amounts recognized in the Balance Sheets $ — $ 16 $ 1 $ 7 Southern Power Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Other current assets/Other current liabilities $ 1 $ 3 $ 3 $ 6 Other deferred charges and assets/Other deferred credits and liabilities — 1 1 2 Foreign currency derivatives: Other current assets/Other current liabilities — 23 — 23 Other deferred charges and assets/Other deferred credits and liabilities 60 — 75 — Total derivatives designated as hedging instruments in cash flow and fair value hedges $ 61 $ 27 $ 79 $ 31 Derivatives not designated as hedging instruments Energy-related derivatives: Other current assets/Other current liabilities $ 1 $ — $ — $ — Total derivatives not designated as hedging instruments $ 1 $ — $ — $ — Gross amounts recognized $ 62 $ 27 $ 79 $ 31 Gross amounts offset $ (1 ) $ (1 ) $ (3 ) $ (3 ) Net amounts recognized in the Balance Sheets $ 61 $ 26 $ 76 $ 28 As of June 30, 2019 As of December 31, 2018 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/Liabilities from risk management activities-current $ 1 $ 10 $ 2 $ 8 Other deferred charges and assets/Other deferred credits and liabilities — 1 — 1 Total derivatives designated as hedging instruments for regulatory purposes $ 1 $ 11 $ 2 $ 9 Derivatives designated as hedging instruments in cash flow and fair value hedges Energy-related derivatives: Assets from risk management activities/Liabilities from risk management activities-current $ — $ 4 $ — $ 1 Total derivatives designated as hedging instruments in cash flow and fair value hedges $ — $ 4 $ — $ 1 Derivatives not designated as hedging instruments Energy-related derivatives: Assets from risk management activities/Liabilities from risk management activities-current $ 285 $ 298 $ 559 $ 574 Other deferred charges and assets/Other deferred credits and liabilities 156 219 180 325 Total derivatives not designated as hedging instruments $ 441 $ 517 $ 739 $ 899 Gross amounts of recognized $ 442 $ 532 $ 741 $ 909 Gross amounts offset (a) $ (315 ) $ (493 ) $ (508 ) $ (785 ) Net amounts recognized in the Balance Sheets (b) $ 127 $ 39 $ 233 $ 124 (a) Gross amounts offset include cash collateral held on deposit in broker margin accounts of $178 million and $277 million as of June 30, 2019 and December 31, 2018 , respectively. (b) Net amounts of derivative instruments outstanding exclude premium and intrinsic value associated with weather derivatives of $8 million as of December 31, 2018 .
Pre-tax Effects of Unrealized Derivative Gains (Losses) Arising from Energy-Related Derivative Instruments	At June 30, 2019 and December 31, 2018 , 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 at June 30, 2019 Derivative Category and Balance Sheet Location Southern Company (*) Alabama Power Georgia Power Mississippi Power Southern Company Gas (*) (in millions) Energy-related derivatives: Other regulatory assets, current $ (48 ) $ (11 ) $ (25 ) $ (10 ) $ (2 ) Other regulatory assets, deferred (23 ) (5 ) (12 ) (6 ) — Other regulatory liabilities, current 6 3 — — 3 Total energy-related derivative gains (losses) $ (65 ) $ (13 ) $ (37 ) $ (16 ) $ 1 (*) Fair value gains and losses recorded in regulatory assets and liabilities include cash collateral held on deposit in broker margin accounts of $12 million at June 30, 2019 . Regulatory Hedge Unrealized Gain (Loss) Recognized in the Balance Sheet at December 31, 2018 Derivative Category and Balance Sheet Location Southern Company Alabama Power Georgia Power Mississippi Power Southern Company Gas (in millions) Energy-related derivatives: Other regulatory assets, current $ (19 ) $ (3 ) $ (6 ) $ (2 ) $ (8 ) Other regulatory assets, deferred (16 ) (3 ) (9 ) (4 ) — Assets held for sale, current (6 ) — — — — Other regulatory liabilities, current 1 — — — 1 Total energy-related derivative gains (losses) $ (40 ) $ (6 ) $ (15 ) $ (6 ) $ (7 )
Pre-tax Effects of Interest Rate Derivatives, Designated as Cash Flow Hedging Instruments	For the three and six months ended June 30, 2019 and 2018 , the pre-tax effects of cash flow hedge accounting on accumulated OCI were as follows: Gain (Loss) Recognized in OCI on Derivative For the Three Months For the Six Months 2019 2018 2019 2018 (in millions) (in millions) Southern Company Energy-related derivatives $ (6 ) $ — $ (6 ) $ 12 Interest rate derivatives (37 ) — (37 ) (2 ) Foreign currency derivatives (1 ) (73 ) (39 ) (21 ) Total $ (44 ) $ (73 ) $ (82 ) $ (11 ) Georgia Power Interest rate derivatives $ (37 ) $ — $ (37 ) $ — Total $ (37 ) $ — $ (37 ) $ — Southern Power Energy-related derivatives $ (2 ) $ (1 ) $ (2 ) $ 10 Foreign currency derivatives (1 ) (73 ) (39 ) (21 ) Total $ (3 ) $ (74 ) $ (41 ) $ (11 )
Schedule of Cash Flow Hedging Instruments, Statements of Financial Performance and Financial Position, Location	For the three and six months ended June 30, 2019 and 2018 , 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 For the Six Months 2019 2018 2019 2018 (in millions) (in millions) Southern Company Total depreciation and amortization $ 755 $ 783 $ 1,506 $ 1,552 Gain (loss) on energy-related cash flow hedges (a) (1 ) 1 (4 ) 2 Total interest expense, net of amounts capitalized (429 ) (470 ) (859 ) (928 ) Gain (loss) on interest rate cash flow hedges (a) (5 ) (6 ) (9 ) (11 ) Gain (loss) on foreign currency cash flow hedges (a) (6 ) (7 ) (12 ) (12 ) Gain (loss) on interest rate fair value hedges (b) 19 (7 ) 33 (31 ) Total other income (expense), net 99 78 176 138 Gain (loss) on foreign currency cash flow hedges (a)(c) 16 (73 ) (8 ) (37 ) Southern Power Total depreciation and amortization $ 119 $ 125 $ 237 $ 240 Gain (loss) on energy-related cash flow hedges (a) (1 ) 1 (4 ) 2 Total interest expense, net of amounts capitalized (41 ) (46 ) (84 ) (93 ) Gain (loss) on foreign currency cash flow hedges (a) (6 ) (7 ) (12 ) (12 ) Total other income (expense), net 40 2 41 5 Gain (loss) on foreign currency cash flow hedges (a)(c) 16 (73 ) (8 ) (37 ) (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 Fair Value Hedging Instruments, Statements of Financial Performance and Financial Position, Location	As of June 30, 2019 and December 31, 2018, 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 As of June 30, 2019 As of December 31, 2018 As of June 30, 2019 As of December 31, 2018 (in millions) (in millions) Southern Company Securities due within one year $ (499 ) $ (498 ) $ 1 $ 2 Long-term debt (2,087 ) (2,052 ) 7 41 Georgia Power Securities due within one year $ (499 ) $ (498 ) $ 1 $ 2
Pre-tax Effect of Interest Rate and Energy Related Derivatives	For the three and six months ended June 30, 2019 and 2018 , 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 June 30, Six Months Ended June 30, Derivatives in Non-Designated Hedging Relationships Statements of Income Location 2019 2018 2019 2018 (in millions) (in millions) Southern Company Energy-related derivatives: Natural gas revenues (*) $ 50 $ (28 ) $ 83 $ (43 ) Cost of natural gas (5 ) 2 3 4 Total derivatives in non-designated hedging relationships $ 45 $ (26 ) $ 86 $ (39 ) Southern Company Gas Energy-related derivatives: Natural gas revenues (*) $ 50 $ (28 ) $ 83 $ (43 ) Cost of natural gas (5 ) 2 3 4 Total derivatives in non-designated hedging relationships $ 45 $ (26 ) $ 86 $ (39 ) (*) Excludes immaterial gains (losses) recorded in natural gas revenues associated with weather derivatives for all periods presented.

Acquisitions and Dispositions (

Acquisitions and Dispositions (Tables)	6 Months Ended
	Jun. 30, 2019
Business Combinations [Abstract]
Schedule of Construction Projects	Project Facility Resource Approximate Nameplate Capacity ( MW ) Location Actual/Expected COD PPA Contract Period Projects Completed During the Six Months Ended June 30, 2019 Mankato expansion (a) Natural Gas 385 Mankato, MN May 2019 20 years Projects Under Construction as of June 30, 2019 Wildhorse Mountain (b) Wind 100 Pushmataha County, OK Fourth quarter 2019 20 years Reading (c) Wind 200 Osage and Lyon Counties, KS Second quarter 2020 12 years (a) In November 2018, Southern Power entered into an agreement to sell all of its equity interests in Plant Mankato, including this expansion that was completed during May 2019. This transaction is subject to state commission approvals and is expected to close in fall 2019. The expansion unit started providing energy under a PPA with Northern States Power on June 1, 2019. See " Sales of Natural Gas and Biomass Plants " below. (b) In May 2018, Southern Power purchased 100% of the Wildhorse Mountain facility. Southern Power entered into a tax equity partnership in June 2019 with funding of tax equity amounts expected to occur upon commercial operation. (c) In August 2018, Southern Power purchased 100% of the membership interests of the Reading facility from the joint development arrangement with Renewable Energy Systems Americas, Inc. Southern Power may enter into a tax equity partnership, in which case it would then own 100% of the class B membership interests.
Disposal Groups, Including Discontinued Operations	Gulf Power and Southern Power's equity interests in Plant Oleander and Plant Stanton Unit A (together, the Florida Plants) and Plant Nacogdoches represented individually significant components of Southern Company and Southern Power, respectively; therefore, pre-tax profit for these components for the three and six months ended June 30, 2019 and 2018 is presented below: For the Three Months Ended June 30, For the Six Months Ended June 30, 2019 2018 2019 2018 (in millions) Earnings before income taxes: Gulf Power $ — $ 31 $ — $ 87 Southern Power's Florida Plants $ — $ 14 $ — $ 24 Southern Power's Plant Nacogdoches (*) $ 9 $ 7 $ 16 $ 13 (*) Earnings before income taxes for Plant Nacogdoches for the three and six months ended June 30, 2019 represents the beginning of the corresponding period through June 13, 2019 (the divestiture date). The following table provides Southern Company's and Southern Power's major classes of assets and liabilities classified as held for sale at June 30, 2019 and December 31, 2018 : Southern Company Southern Power (in millions) At June 30, 2019 Assets Held for Sale: Current assets $ 58 $ 10 Total property, plant, and equipment 588 559 Goodwill and other intangible assets 51 40 Other non-current assets 46 — Total Assets Held for Sale $ 743 $ 609 Liabilities Held for Sale: Current liabilities $ 36 $ 10 Other non-current liabilities 39 — Total Liabilities Held for Sale $ 75 $ 10 At December 31, 2018 Assets Held for Sale: Current assets $ 393 $ 8 Total property, plant, and equipment 4,583 536 Other intangible assets 40 40 Other non-current assets 727 — Total Assets Held for Sale $ 5,743 $ 584 Liabilities Held for Sale: Current liabilities $ 425 $ 15 Long-term debt 1,286 — Accumulated deferred income taxes 618 — Other non-current liabilities 932 — Total Liabilities Held for Sale $ 3,261 $ 15

Leases (Tables)

Leases (Tables)	6 Months Ended
	Jun. 30, 2019
Leases [Abstract]
Major Categories of Lease Obligations	The major categories of lease obligations are as follows: As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Electric generating units $ 1,072 $ 150 $ 1,580 $ — $ — $ — Real estate/land 800 4 62 2 395 81 Communication towers 147 1 3 — — 13 Railcars 54 25 27 3 — — Other 145 10 14 2 — — Total $ 2,218 $ 190 $ 1,686 $ 7 $ 395 $ 94
Balance Sheet Amounts Recorded for Operating and Financing Leases	Balance sheet amounts recorded for operating and finance leases are as follows: As of June 30, 2019 Southern Company (*) Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Operating Leases Operating lease ROU assets, net $ 1,907 $ 152 $ 1,492 $ 7 $ 370 $ 95 Operating lease obligations - current $ 241 $ 48 $ 140 $ 2 $ 22 $ 15 Operating lease obligations - non current 1,733 137 1,377 5 373 79 Total operating lease obligations $ 1,974 $ 185 $ 1,517 $ 7 $ 395 $ 94 Finance Leases Finance lease ROU assets, net $ 237 $ 5 $ 142 $ — $ — $ — Finance lease obligations - current $ 24 $ 1 $ 10 $ — $ — $ — Finance lease obligations - noncurrent 220 4 159 — — — Total finance lease obligations $ 244 $ 5 $ 169 $ — $ — $ — (*) Includes operating lease ROU assets, net and operating lease obligations classified as held for sale.
Lease Costs and Other Information	Lease costs for the three and six months ended June 30, 2019 , which includes both amounts recognized as operations and maintenance expense and amounts capitalized as part of the cost of another asset, are as follows: Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) For the Three Months Ended June 30, 2019 Lease cost Operating lease cost $ 77 $ 13 $ 50 $ 1 $ 7 $ 5 Finance lease cost: Amortization of ROU assets 7 — 4 — — — Interest on lease obligations 3 — 4 — — — Total finance lease cost 10 — 8 — — — Short-term lease costs 13 6 6 — — — Variable lease cost 29 1 25 — 1 — Sublease income — — — — — — Total lease cost $ 129 $ 20 $ 89 $ 1 $ 8 $ 5 For the Six Months Ended June 30, 2019 Lease cost Operating lease cost $ 147 $ 20 $ 99 $ 1 $ 14 $ 9 Finance lease cost: Amortization of ROU assets 14 — 7 — — — Interest on lease obligations 6 — 9 — — — Total finance lease cost 20 — 16 — — — Short-term lease costs 30 11 12 — — — Variable lease cost 48 1 41 — 3 — Sublease income — — — — — — Total lease cost $ 245 $ 32 $ 168 $ 1 $ 17 $ 9 Georgia Power has variable lease payments that are based on the amount of energy produced by certain renewable generating facilities subject to PPAs. Other information with respect to cash and noncash activities related to leases, as well as weighted-average lease terms and discount rates, is as follows: For the Six Months Ended June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Other information Cash paid for amounts included in the measurements of lease obligations: Operating cash flows from operating leases $ 129 $ 20 $ 75 $ 1 $ 12 $ 9 Operating cash flows from finance leases 2 — 10 — — — Financing cash flows from finance leases 16 — 3 — — — ROU assets obtained in exchange for new operating lease obligations 55 5 13 — — 13 ROU assets obtained in exchange for new finance lease obligations 33 1 28 — — — As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas Weighted-average remaining lease term in years: Operating leases 14.0 3.6 10.5 7.0 33.5 9.7 Finance leases 18.3 12.8 11.0 N/A N/A N/A Weighted-average discount rate: Operating leases 4.53 % 3.33 % 4.46 % 4.06 % 5.68 % 3.73 % Finance leases 5.05 % 3.67 % 10.69 % N/A N/A N/A
Maturities of Operating Lease Liabilities	Maturities of lease liabilities are as follows: As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2019 (remaining) $ 178 $ 33 $ 129 $ 1 $ 13 $ 9 2020 295 53 203 2 22 17 2021 279 52 198 1 23 16 2022 268 52 196 1 23 13 2023 204 4 197 1 24 11 Thereafter 1,661 2 990 2 849 49 Total 2,885 196 1,913 8 954 115 Less: Present value discount 911 11 396 1 559 21 Operating lease obligations $ 1,974 $ 185 $ 1,517 $ 7 $ 395 $ 94 Finance leases: 2019 (remaining) $ 16 $ — $ 16 $ — $ — $ — 2020 33 1 28 — — — 2021 27 1 25 — — — 2022 23 1 25 — — — 2023 18 1 25 — — — Thereafter 266 1 165 — — — Total 383 5 284 — — — Less: Present value discount 139 — 115 — — — Finance lease obligations $ 244 $ 5 $ 169 $ — $ — $ —
Maturities of Finance Lease Liabilities	Maturities of lease liabilities are as follows: As of June 30, 2019 Southern Company Alabama Power Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) Maturity Analysis Operating leases: 2019 (remaining) $ 178 $ 33 $ 129 $ 1 $ 13 $ 9 2020 295 53 203 2 22 17 2021 279 52 198 1 23 16 2022 268 52 196 1 23 13 2023 204 4 197 1 24 11 Thereafter 1,661 2 990 2 849 49 Total 2,885 196 1,913 8 954 115 Less: Present value discount 911 11 396 1 559 21 Operating lease obligations $ 1,974 $ 185 $ 1,517 $ 7 $ 395 $ 94 Finance leases: 2019 (remaining) $ 16 $ — $ 16 $ — $ — $ — 2020 33 1 28 — — — 2021 27 1 25 — — — 2022 23 1 25 — — — 2023 18 1 25 — — — Thereafter 266 1 165 — — — Total 383 5 284 — — — Less: Present value discount 139 — 115 — — — Finance lease obligations $ 244 $ 5 $ 169 $ — $ — $ —
Lease Income, Sales-type Leases	Lease income for the three and six months ended June 30, 2019 is as follows: Southern Company Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) For the Three Months Ended June 30, 2019 Lease income - interest income on sales-type leases $ 2 $ — $ 2 $ — $ — Lease income - operating leases 67 19 — 39 9 Variable lease income 115 — — 125 — Total lease income $ 184 $ 19 $ 2 $ 164 $ 9 For the Six Months Ended June 30, 2019 Lease income - interest income on sales-type leases $ 5 $ — $ 5 $ — $ — Lease income - operating leases 139 39 — 80 17 Variable lease income 182 — — 198 — Total lease income $ 326 $ 39 $ 5 $ 278 $ 17
Lease Income, Operating Leases	Lease income for the three and six months ended June 30, 2019 is as follows: Southern Company Georgia Power Mississippi Power Southern Power Southern Company Gas (in millions) For the Three Months Ended June 30, 2019 Lease income - interest income on sales-type leases $ 2 $ — $ 2 $ — $ — Lease income - operating leases 67 19 — 39 9 Variable lease income 115 — — 125 — Total lease income $ 184 $ 19 $ 2 $ 164 $ 9 For the Six Months Ended June 30, 2019 Lease income - interest income on sales-type leases $ 5 $ — $ 5 $ — $ — Lease income - operating leases 139 39 — 80 17 Variable lease income 182 — — 198 — Total lease income $ 326 $ 39 $ 5 $ 278 $ 17
Undiscounted Cash Flows to be Received Under Tolling Arrangements Accounted for as Sales-type Leases	The undiscounted cash flows to be received under tolling arrangements accounted for as sales-type leases are as follows: As of June 30, 2019 Southern Company Mississippi Power (in millions) 2019 (remaining) $ 7 $ 7 2020 14 14 2021 14 14 2022 13 13 2023 12 12 Thereafter 135 135 Total undiscounted cash flows $ 195 $ 195 Lease receivable 106 106 Difference between undiscounted cash flows and discounted cash flows $ 89 $ 89
Undiscounted Cash Flows to be Received Under PPAs Accounted for as Operating Leases	The undiscounted cash flows to be received under operating leases and contracts accounted for as operating leases (adjusted for intercompany eliminations) are as follows: As of June 30, 2019 Southern Company Georgia Power Southern Power Southern Company Gas (in millions) 2019 (remaining) $ 75 $ 13 $ 52 $ 17 2020 125 26 65 35 2021 118 18 66 35 2022 109 8 68 34 2023 103 2 69 34 Thereafter 1,142 — 350 497 Total $ 1,672 $ 67 $ 670 $ 652

Segment and Related Informati_2

Segment and Related Information (Tables)	6 Months Ended
	Jun. 30, 2019
Segment Reporting [Abstract]
Financial Data for Business Segments	Financial data for business segments and products and services for the three and six months ended June 30, 2019 and 2018 was as follows: Electric Utilities Traditional Electric Operating Companies Southern Power Eliminations Total Southern Company Gas All Other Eliminations Consolidated (in millions) Three Months Ended June 30, 2019 Operating revenues $ 3,899 $ 510 $ (119 ) $ 4,290 $ 689 $ 186 $ (67 ) $ 5,098 Segment net income (loss) (a)(b)(c)(d) 782 174 — 956 106 (154 ) (9 ) 899 Six Months Ended June 30, 2019 Operating revenues $ 7,343 $ 953 $ (211 ) $ 8,085 $ 2,163 $ 368 $ (106 ) $ 10,510 Segment net income (loss) (a)(b)(c)(d) 1,346 230 — 1,576 376 1,041 (11 ) 2,982 At June 30, 2019 Goodwill $ — $ 2 $ — $ 2 $ 5,015 $ 265 $ — $ 5,282 Total assets 78,314 14,518 (783 ) 92,049 20,761 3,343 (1,286 ) 114,867 Three Months Ended June 30, 2018 Operating revenues $ 4,124 $ 555 $ (114 ) $ 4,565 $ 730 $ 381 $ (49 ) $ 5,627 Segment net income (loss) (a)(b)(d) (48 ) 22 — (26 ) (31 ) (100 ) 3 (154 ) Six Months Ended June 30, 2018 Operating revenues $ 8,104 $ 1,064 $ (220 ) $ 8,948 $ 2,369 $ 782 $ (100 ) $ 11,999 Segment net income (loss) (a)(b)(d)(e) 563 143 — 706 248 (174 ) 4 784 At December 31, 2018 Goodwill $ — $ 2 $ — $ 2 $ 5,015 $ 298 $ — $ 5,315 Total assets 79,382 14,883 (306 ) 93,959 21,448 3,285 (1,778 ) 116,914 (a) Attributable to Southern Company. (b) Segment net income (loss) for the traditional electric operating companies includes pre-tax charges for estimated losses on plants under construction of $4 million ( $3 million after tax) and $1.1 billion ( $0.8 billion after tax) for the three months ended June 30, 2019 and 2018 , respectively, and $6 million ( $5 million after tax) and $1.1 billion ( $0.8 billion after tax) for the six months ended June 30, 2019 and 2018 , respectively. See Note 2 to the financial statements in Item 8 of the Form 10-K and Note (B) under "Georgia Power – Nuclear Construction" and " Mississippi Power – Kemper County Energy Facility " for additional information. (c) Segment net income (loss) for the "All Other" column includes the preliminary pre-tax gain associated with the sale of Gulf Power of $2.5 billion ( $1.3 billion after tax) for the six months ended June 30, 2019 , of which $(15) million ( $(11) million after tax) was recorded in the three months ended June 30, 2019 , as well as a goodwill impairment charge of $32 million for the three and six months ended June 30, 2019 in contemplation of the sale of one of PowerSecure's business units. See Note (K) under " Southern Company " for additional information. (d) Segment net income (loss) for Southern Power includes a $23 million pre-tax gain ( $88 million gain after tax) on the sale of Plant Nacogdoches for the three and six months ended June 30, 2019 and a pre-tax impairment charge of $119 million ( $89 million after tax) for the three and six months ended June 30, 2018 related to the sale of Southern Power's Florida Plants. See Note (K) under " Southern Power " and Note 15 to the financial statements in Item 8 of the Form 10-K under "Southern Power – Sale of Natural Gas Plants" for additional information. (e) Segment net income (loss) for Southern Company Gas includes a goodwill impairment charge of $42 million for the six months ended June 30, 2018 related to the sale of Pivotal Home Solutions. See Note 15 to the financial statements in Item 8 of the Form 10-K under "Southern Company Gas" for additional information. Business segment financial data for the three and six months ended June 30, 2019 and 2018 was as follows: Gas Distribution Operations (a) Gas Pipeline Investments Wholesale Gas Services (b) Gas Marketing Services (c)(d) Total All Other Eliminations Consolidated (in millions) Three Months Ended June 30, 2019 Operating revenues $ 568 $ 8 $ 48 $ 58 $ 682 $ 13 $ (6 ) $ 689 Segment net income (loss) 58 25 23 (3 ) 103 3 — 106 Six Months Ended June 30, 2019 Operating revenues $ 1,740 $ 16 $ 134 $ 287 $ 2,177 $ 24 $ (38 ) $ 2,163 Segment net income (loss) 191 57 70 58 376 — — 376 Total assets at June 30, 2019 17,397 1,768 668 1,527 21,360 10,934 (11,533 ) 20,761 Three Months Ended June 30, 2018 Operating revenues $ 643 $ 8 $ (16 ) $ 89 $ 724 $ 11 $ (5 ) $ 730 Segment net income (loss) 68 21 (21 ) (76 ) (8 ) (23 ) — (31 ) Six Months Ended June 30, 2018 Operating revenues $ 1,856 $ 16 $ 150 $ 359 $ 2,381 $ 26 $ (38 ) $ 2,369 Segment net income (loss) 216 48 83 (63 ) 284 (36 ) — 248 Total assets at December 31, 2018 17,266 1,763 1,302 1,587 21,918 11,112 (11,582 ) 21,448 (a) Operating revenues for the three gas distribution operations dispositions were $70 million and $237 million for the three and six months ended June 30, 2018 , respectively. See Note 15 to the financial statements in Item 8 of the Form 10-K under "Southern Company Gas" for additional information. (b) The revenues for wholesale gas services are 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 June 30, 2019 $ 1,223 $ 63 $ 1,286 $ 1,238 $ 48 Three Months Ended June 30, 2018 1,336 102 1,438 1,454 (16 ) Six Months Ended June 30, 2019 $ 3,148 $ 151 $ 3,299 $ 3,165 $ 134 Six Months Ended June 30, 2018 3,274 269 3,543 3,393 150 (c) Operating revenues for Pivotal Home Solutions were $24 million and $55 million for the three and six months ended June 30, 2018 , respectively. See Note 15 to the financial statements in Item 8 of the Form 10-K under "Southern Company Gas" for additional information on the sale of Pivotal Home Solutions. (d) Segment net income (loss) for gas marketing services includes a loss on disposition of $36 million for the three and six months ended June 30, 2018 and a goodwill impairment charge of $42 million for the six months ended June 30, 2018 related to the sale of Pivotal Home Solutions. See Note 15 to the financial statements in Item 8 of the Form 10-K under "Southern Company Gas" for additional information.
Financial Data for Products and Services	Products and Services Electric Utilities' Revenues Retail Wholesale Other Total (in millions) Three Months Ended June 30, 2019 $ 3,540 $ 542 $ 208 $ 4,290 Three Months Ended June 30, 2018 3,740 616 209 4,565 Six Months Ended June 30, 2019 $ 6,623 $ 1,041 $ 421 $ 8,085 Six Months Ended June 30, 2018 7,308 1,239 401 8,948 Southern Company Gas' Revenues Gas (a) Gas (b) Other Total (in millions) Three Months Ended June 30, 2019 $ 563 $ 58 $ 68 $ 689 Three Months Ended June 30, 2018 638 89 3 730 Six Months Ended June 30, 2019 $ 1,724 $ 287 $ 152 $ 2,163 Six Months Ended June 30, 2018 1,838 359 172 2,369 (a) Operating revenues for the three gas distribution operations dispositions were $70 million and $237 million for the three and six months ended June 30, 2018 , respectively. (b) Operating revenues for Pivotal Home Solutions were $24 million and $55 million for the three and six months ended June 30, 2018 , respectively.

Introduction - Narrative (Detai

Introduction - Narrative (Details)	1 Months Ended	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)	Jun. 30, 2019USD ($)business_unit	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Goodwill impairment		$ 32,000,000		$ 32,000,000
SOUTHERN Co GAS
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Goodwill impairment		0	$ 0	0	$ 42,000,000
Inventory decrement		7,000,000	$ 0	$ 10,000,000	$ 0
ALABAMA POWER CO
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in ARO	$ 308,000,000
MISSISSIPPI POWER CO
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Increase in ARO	$ 58,000,000
Disposal Group, Held-for-sale, Not Discontinued Operations | PowerSecure International, Inc.
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Goodwill impairment		$ 32,000,000
Number Of Business Units | business_unit		1

Introduction - Goodwill (Detail

Introduction - Goodwill (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Goodwill [Line Items]
Goodwill	$ 5,282	$ 5,315
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 - Other Intangible

Introduction - Other Intangible Assets (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Other intangible assets subject to amortization:
Gross Carrying Amount	$ 728	$ 773
Accumulated Amortization	(253)	(235)
Other Intangible Assets, Net	475	538
Other intangible assets not subject to amortization:
Federal Communications Commission licenses	75	75
Total other intangible assets
Gross Carrying Amount	803	848
Other Intangible Assets, Net	550	613
Customer relationships
Other intangible assets subject to amortization:
Gross Carrying Amount	211	223
Accumulated Amortization	(105)	(94)
Other Intangible Assets, Net	106	129
Trade names
Other intangible assets subject to amortization:
Gross Carrying Amount	70	70
Accumulated Amortization	(23)	(21)
Other Intangible Assets, Net	47	49
Other
Other intangible assets subject to amortization:
Gross Carrying Amount	12	11
Accumulated Amortization	(7)	(5)
Other Intangible Assets, Net	5	6
SOUTHERN POWER CO
Other intangible assets subject to amortization:
Accumulated Amortization	(60)	(61)
SOUTHERN POWER CO | PPA fair value adjustments
Other intangible assets subject to amortization:
Gross Carrying Amount	371	405
Accumulated Amortization	(60)	(61)
Other Intangible Assets, Net	311	344
SOUTHERN Co GAS
Other intangible assets subject to amortization:
Gross Carrying Amount	246	246
Accumulated Amortization	(161)	(145)
Other Intangible Assets, Net	85	101
Total other intangible assets
Other Intangible Assets, Net	85	101
SOUTHERN Co GAS | Customer relationships
Other intangible assets subject to amortization:
Gross Carrying Amount	156	156
Accumulated Amortization	(95)	(84)
Other Intangible Assets, Net	61	72
SOUTHERN Co GAS | Trade names
Other intangible assets subject to amortization:
Gross Carrying Amount	26	26
Accumulated Amortization	(8)	(7)
Other Intangible Assets, Net	18	19
SOUTHERN Co GAS | Storage and transportation contracts
Other intangible assets subject to amortization:
Gross Carrying Amount	64	64
Accumulated Amortization	(58)	(54)
Other Intangible Assets, Net	$ 6	$ 10

Introduction - Intangibles, Amo

Introduction - Intangibles, Amortization (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 15	$ 32
SOUTHERN POWER CO
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	4	10
SOUTHERN Co GAS
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	8	16
Gas Marketing Services | SOUTHERN Co GAS
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	6	12
Wholesale Gas Services | SOUTHERN Co GAS
Finite-Lived Intangible Assets [Line Items]
Amortization of intangible assets	$ 2	$ 4

Introduction - Restricted Cash

Introduction - Restricted Cash (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	$ 1,383	$ 1,396
Cash and cash equivalents held for sale		9
Restricted cash:
Total cash, cash equivalents, and restricted cash	1,386	1,519	$ 2,017	$ 2,147
Restricted cash
Restricted cash:
Restricted cash		0
Other accounts and notes receivable
Restricted cash:
Restricted cash	4	114
GEORGIA POWER CO
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	10	4
Cash and cash equivalents held for sale		0
Restricted cash:
Total cash, cash equivalents, and restricted cash	10	112	11	852
GEORGIA POWER CO | Restricted cash
Restricted cash:
Restricted cash		108
GEORGIA POWER CO | Other accounts and notes receivable
Restricted cash:
Restricted cash		0
SOUTHERN Co GAS
Restricted Cash and Cash Equivalents Items [Line Items]
Cash and cash equivalents	56	64
Cash and cash equivalents held for sale		0
Restricted cash:
Total cash, cash equivalents, and restricted cash	60	70	$ 75	$ 78
SOUTHERN Co GAS | Restricted cash
Restricted cash:
Restricted cash		0
SOUTHERN Co GAS | Other accounts and notes receivable
Restricted cash:
Restricted cash	$ 4	$ 6

Introduction - Asset Retirement

Introduction - Asset Retirement Obligations (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at December 31, 2018	$ 9,394
Liabilities incurred	6
Liabilities settled	(142)
Accretion	197
Cash flow revisions	452
Balance at June 30, 2019	9,907
ALABAMA POWER CO
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at December 31, 2018	3,210
Liabilities incurred	0
Liabilities settled	(43)
Accretion	70
Cash flow revisions	308
Balance at June 30, 2019	3,545
MISSISSIPPI POWER CO
Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]
Balance at December 31, 2018	160
Liabilities incurred	0
Liabilities settled	(17)
Accretion	2
Cash flow revisions	59
Balance at June 30, 2019	$ 204

Regulatory Matters - Cost Recov

Regulatory Matters - Cost Recovery Clauses (Details) - USD ($) $ in Millions	Jun. 30, 2019	Feb. 05, 2019	Dec. 31, 2018
ALABAMA POWER CO
Loss Contingencies [Line Items]
Rate RSE Refund Liability		$ 75
ALABAMA POWER CO | Deferred under recovered regulatory clause revenues
Loss Contingencies [Line Items]
Rate CNP Compliance	$ 0		$ 42
Rate CNP PPA	25		25
Retail Energy Cost Recovery	0		109
ALABAMA POWER CO | Customer accounts receivable
Loss Contingencies [Line Items]
Rate CNP Compliance	10		0
Retail Energy Cost Recovery	8		0
ALABAMA POWER CO | Other regulatory liabilities, deferred
Loss Contingencies [Line Items]
Natural Disaster Reserve	19		20
GEORGIA POWER CO | Receivables – under recovered fuel clause revenues
Loss Contingencies [Line Items]
Fuel Cost Recovery	69		115
MISSISSIPPI POWER CO | Over recovered regulatory clause liabilities
Loss Contingencies [Line Items]
Fuel Cost Recovery	$ 9		$ 8

Regulatory Matters - Alabama Po

Regulatory Matters - Alabama Power (Details) - ALABAMA POWER CO - Restatement Adjustment $ in Millions	Apr. 15, 2019USD ($)
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Capitalized asset retirement costs, net	$ 700
Remaining amounts of regulatory assets for which no return on investment during recovery period is provided	700
Plant Gorgas Units 8, 9, and 10
Error Corrections and Prior Period Adjustments Restatement [Line Items]
Net investment costs	654
Remaining amounts of regulatory assets for which no return on investment during recovery period is provided	$ 654

Regulatory Matters - Georgia Po

Regulatory Matters - Georgia Power (Details) - GEORGIA POWER CO $ in Millions	Jul. 29, 2019MW	Jul. 16, 2019MW	Jun. 28, 2019	Jun. 30, 2019USD ($)MW	Dec. 31, 2022USD ($)	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Public Utilities, General Disclosures [Line Items]
Alternate Rate Plan period			3 years
Requested increases effective January 1, 2020				$ 563
Requested increases effective January 1, 2021				145
Requested increases effective January 1, 2022				234
Proposed retail ROE			10.90%
Proposed equity ratio			56.00%
Percentage of earnings above the top of allowed ROE range shared with customers			66.67%
Percentage of earnings above the top of allowed ROE range not shared with customers			33.33%
Cost recovery, new nuclear				99
Cost recovery, estimate, nuclear fuel				50
Under recovered CCR compliance cost				$ 135
Requested recovery of under recovered CCR compliance costs, period				3 years
Approved capacity of units for solar generation resources (mw) | MW				2,210
Approved capacity of units for investment portfolio (mw) | MW				80
Minimum
Public Utilities, General Disclosures [Line Items]
Allowed retail ROE			10.00%
Maximum
Public Utilities, General Disclosures [Line Items]
Allowed retail ROE			12.00%
Plant Hammond Units 1 Through 4
Public Utilities, General Disclosures [Line Items]
Net book value of planned units retirements				$ 500
Plant McIntosh Unit 1
Public Utilities, General Disclosures [Line Items]
Net book value of planned units retirements				40
Plant Mitchell Unit 3
Public Utilities, General Disclosures [Line Items]
Net book value of planned units retirements				$ 8
Subsequent Event
Public Utilities, General Disclosures [Line Items]
Rejected proposed capacity of units for certification | MW		25
Subsequent Event | Plant Hammond Units 1 Through 4
Public Utilities, General Disclosures [Line Items]
Capacity of units included in request for decertification of units (mw) | MW	840
Subsequent Event | Plant McIntosh Unit 1
Public Utilities, General Disclosures [Line Items]
Capacity of units included in request for decertification of units (mw) | MW	142.5
Remaining Net Book Value Of Retired Assets | Maximum
Public Utilities, General Disclosures [Line Items]
Regulatory asset, amortization period				3 years
Scenario, Forecast
Public Utilities, General Disclosures [Line Items]
Recovery of estimated under recovered CCR rule costs					$ 655	$ 395	$ 277

Regulatory Matters - Requested

Regulatory Matters - Requested Recovery of Proposed Increases (Details) - GEORGIA POWER CO $ in Millions	Jun. 30, 2019USD ($)
Public Utilities, General Disclosures [Line Items]
2020	$ 563
2021	145
2022	234
Levelized
Public Utilities, General Disclosures [Line Items]
2020	209
2021	0
2022	0
CCR ARO
Public Utilities, General Disclosures [Line Items]
2020	158
2021	140
2022	227
Environmental Compliance Cost Recovery
Public Utilities, General Disclosures [Line Items]
2020	165
2021	0
2022	0
Demand-Side Management
Public Utilities, General Disclosures [Line Items]
2020	14
2021	2
2022	1
Municipal Franchise Fee
Public Utilities, General Disclosures [Line Items]
2020	17
2021	3
2022	$ 5

Regulatory Matters - Nuclear Co

Regulatory Matters - Nuclear Construction (Details) - GEORGIA POWER CO $ in Millions

Jan. 01, 2021

Jan. 01, 2020

Aug. 30, 2019USD ($)

Feb. 19, 2019USD ($)

Jan. 11, 2018USD ($)

Jan. 01, 2016

Dec. 31, 2018USD ($)appeal

Aug. 31, 2018USD ($)

Jun. 30, 2019USD ($)

Dec. 31, 2019USD ($)

Dec. 31, 2018USD ($)

Dec. 31, 2012utilityMW

Dec. 31, 2009USD ($)

Dec. 31, 2022USD ($)

Dec. 31, 2014

Dec. 31, 2013

Loss Contingencies [Line Items]

Number of construction units approved | utility

2

Electric generating capacity in mega watts under consortium agreement | MW

1,100

Additional construction capital costs

$ 3,300

Estimated in-service capital cost

$ 4,418

Financing costs collected, net of tax

$ 2,000

Increase in NCCR tariff

$ 88

Amendment to estimated in-service capital cost

$ 5,680

Retail rate of return on common equity

10.95%

Number of appeals | appeal

2

Requested capital construction costs

$ 5,400

Deferred approval of expenditures related to administrative claim

$ 51.6

Scenario, Forecast

Loss Contingencies [Line Items]

Requested capital construction costs

$ 1,200

FFB Loan

Loss Contingencies [Line Items]

Long-term line of credit

3,460

Eligible project costs to be reimbursed

$ 5,130

Plant Vogtle Units 3 And 4

Loss Contingencies [Line Items]

Proportionate ownership share

45.70%

Construction financing costs

$ 2,000

Base project capital cost forecast, monthly

50

Monthly AFUDC

12

Percentage of ownership interest required for voting for continuing construction

90.00%

90.00%

Cost settlement agreement revised forecast, net of payments

$ 7,300

Public utilities, approved return on equity percentage

10.00%

Public utilities, approved return on equity, monthly percentage decrease

0.10%

Return on equity reduction, negative impact on earnings

$ 100

Requested capital construction costs

$ 578

Guarantor obligations

$ 1,700

Customer refund

$ 188

Plant Vogtle Units 3 And 4 | Scenario, Forecast

Loss Contingencies [Line Items]

Construction financing costs

$ 3,100

Public utilities, approved return on equity percentage

5.30%

8.30%

Return on equity reduction, negative impact on earnings

$ 70

$ 630

Plant Vogtle Units 3 And 4 | Vogtle Owners

Loss Contingencies [Line Items]

Period of notice required in the event letters of credit are not renewed

30 days

Regulatory Matters - Nuclear _2

Regulatory Matters - Nuclear Construction Cost and Schedule (Details) - GEORGIA POWER CO - Plant Vogtle Units 3 And 4 $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Loss Contingencies [Line Items]
Base project capital cost forecast	$ 8,000
Construction contingency estimate	400
Total project capital cost forecast	8,400
Net investment as of June 30, 2019	(5,200)
Remaining estimate to complete	3,200
Expected capitalized costs	315
Guarantor obligations	1,700
Customer refund	$ 188

Regulatory Matters - Mississipp

Regulatory Matters - Mississippi Power (Details) - USD ($) $ in Millions	Jan. 01, 2019	Jul. 09, 2019
MISSISSIPPI POWER CO | Subsequent Event
Loss Contingencies [Line Items]
Proportionate ownership share		50.00%
Total estimated cost		$ 66
MISSISSIPPI POWER CO | Subsequent Event | Ash Pond Closure
Loss Contingencies [Line Items]
Total estimated cost		17
MISSISSIPPI POWER CO | MRA Revenue
Loss Contingencies [Line Items]
Decrease in base rate under cost based electric tariff	$ 3.7
Mississippi Power And Gulf Power | Subsequent Event
Loss Contingencies [Line Items]
Total estimated cost		$ 125

Regulatory Matters - Kemper Cou

Regulatory Matters - Kemper County Energy Facility (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	6 Months Ended		48 Months Ended
	Dec. 31, 2018	Jun. 30, 2019	Dec. 31, 2019	Jun. 30, 2019	Dec. 31, 2023
Loss Contingencies [Line Items]
Liabilities incurred				$ 6
MISSISSIPPI POWER CO
Loss Contingencies [Line Items]
Liabilities incurred				0
MISSISSIPPI POWER CO | Kemper IGCC
Loss Contingencies [Line Items]
Pre-tax charge to income		$ 4		6
Asset retirement obligation, liabilities incurred, net of tax		3		5
Asset retirement obligation, expected cost		$ 10		$ 10
Government grants received	$ 387
MISSISSIPPI POWER CO | Kemper IGCC | Scenario, Forecast
Loss Contingencies [Line Items]
Liabilities incurred			$ 7
MISSISSIPPI POWER CO | Kemper IGCC | Minimum | Scenario, Forecast
Loss Contingencies [Line Items]
Liabilities incurred					$ 2
MISSISSIPPI POWER CO | Kemper IGCC | Maximum | Scenario, Forecast
Loss Contingencies [Line Items]
Liabilities incurred					$ 6

Regulatory Matters - Southern C

Regulatory Matters - Southern Company Gas (Details) $ in Millions	Jun. 03, 2019USD ($)	Apr. 16, 2019USD ($)intervenor	Apr. 08, 2019USD ($)	Dec. 31, 2018USD ($)	Dec. 31, 2018USD ($)	Nov. 30, 2018USD ($)	Dec. 31, 2017
Nicor Gas
Loss Contingencies [Line Items]
Approved increase (decrease) in fuel rates amount						$ 230
Public utilities, approved return on equity percentage		9.86%				10.60%
Regulatory equity ratio		54.00%				54.00%	52.00%
Number of intervenors | intervenor		2
Requested increase in rate amounts		$ 180
Atlanta Gas Light
Loss Contingencies [Line Items]
Public utilities, approved return on equity percentage	10.75%
Regulatory equity ratio	55.00%
Requested increase in rate amounts	$ 96
Virginia Natural Gas
Loss Contingencies [Line Items]
Approved increase (decrease) in fuel rates amount					$ (14)
Bill credits				$ 14
Virginia Natural Gas | SAVE
Loss Contingencies [Line Items]
Infrastructure replacement program, proposed investment amount			$ 370
Infrastructure replacement program, petitioned investment renewal term			5 years
Infrastructure replacement program, petitioned investment term			6 years
Infrastructure replacement program, proposed investment variance amount			$ 10
Virginia Natural Gas | SAVE | 2018
Loss Contingencies [Line Items]
Approved investment amount			35
Virginia Natural Gas | SAVE | 2019
Loss Contingencies [Line Items]
Infrastructure replacement program, proposed investment amount			40
Infrastructure replacement program, proposed investment variance amount			6
Virginia Natural Gas | SAVE | 2020
Loss Contingencies [Line Items]
Infrastructure replacement program, proposed investment amount			50
Infrastructure replacement program, proposed investment variance amount			8
Virginia Natural Gas | SAVE | 2021
Loss Contingencies [Line Items]
Infrastructure replacement program, proposed investment amount			60
Infrastructure replacement program, proposed investment variance amount			9
Virginia Natural Gas | SAVE | 2022
Loss Contingencies [Line Items]
Infrastructure replacement program, proposed investment amount			70
Infrastructure replacement program, proposed investment variance amount			10
Virginia Natural Gas | SAVE | 2023
Loss Contingencies [Line Items]
Infrastructure replacement program, proposed investment amount			70
Infrastructure replacement program, proposed investment variance amount			10
Virginia Natural Gas | SAVE | 2024
Loss Contingencies [Line Items]
Infrastructure replacement program, proposed investment amount			70
Infrastructure replacement program, proposed investment variance amount			$ 10
Minimum | Atlanta Gas Light
Loss Contingencies [Line Items]
Public utilities, approved return on equity percentage	10.55%
Maximum | Atlanta Gas Light
Loss Contingencies [Line Items]
Public utilities, approved return on equity percentage	10.95%

Regulatory Matters - FERC Matte

Regulatory Matters - FERC Matters (Details) - Open Access Transmission Tariff - SCS	May 10, 2018
Loss Contingencies [Line Items]
Public utilities, approved return on equity percentage	10.60%
Moratorium period	5 years

Contingencies - General Litigat

Contingencies - General Litigation Matters (Details) $ in Millions	Mar. 14, 2019plaintiff	Nov. 30, 2018USD ($)defendantplaintiff	May 31, 2018USD ($)agreement	Apr. 30, 2018	Jun. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Dec. 31, 2017claim
Loss Contingencies [Line Items]
Number of plaintiffs | plaintiff		10
Pending Litigation | Putative Securities Class Action
Loss Contingencies [Line Items]
Increase in the purported class period							1 day
Pending Litigation | Shareholder Derivative Lawsuits
Loss Contingencies [Line Items]
Pending number of claims | claim							2
Stay period			30 days	30 days
MISSISSIPPI POWER CO | Pending Litigation | Martin Product Sales, LLC Litigation
Loss Contingencies [Line Items]
Number of agreements | agreement			2
MISSISSIPPI POWER CO | Pending Litigation | Purported Violations Of Mississippi Consumer Protection Act
Loss Contingencies [Line Items]
Number of plaintiffs | plaintiff	4
Number of defendants | defendant		3
Underpayment of refunds		$ 23.5
Martin Product Sales, LLC Litigation | Martin Product Sales, LLC Litigation
Loss Contingencies [Line Items]
Damages sought by litigation			$ 143
SOUTHERN POWER CO
Loss Contingencies [Line Items]
Withholding of construction contract payments						$ 26
Gain on funds received in excess of initial replacement costs, after tax					$ 12
SOUTHERN POWER CO | RE Roserock, LLC | RE Roserock, LLC
Loss Contingencies [Line Items]
Ownership percentage by parent					51.00%	51.00%

Contingencies - Environmental R

Contingencies - Environmental Remediation (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
GEORGIA POWER CO
Loss Contingencies [Line Items]
Environmental remediation liability, current and former sites	$ 18	$ 23
SOUTHERN Co GAS
Loss Contingencies [Line Items]
Environmental remediation liability, current and former sites	283	$ 294
SOUTHERN Co GAS | Location One
Loss Contingencies [Line Items]
Environmental remediation liability, current and former sites	$ 2

Contingencies - Other Matters (

Contingencies - Other Matters (Details)	60 Months Ended
	Jan. 15, 2024USD ($)	Jun. 30, 2019USD ($)Facility	May 17, 2019USD ($)
ALABAMA POWER CO | Damage from Unpermitted Discharge of Fluids and/or Pollutants | Plant Gadsden
Loss Contingencies [Line Items]
Possible environmental penalty | $			$ 250,000
GULF POWER CO | Scenario, Forecast | Plant Daniel Units 1 And 2
Loss Contingencies [Line Items]
Undivided ownership interest to be sold	50.00%
Undivided ownership interest, ownership interest in individual unit	100.00%
MISSISSIPPI POWER CO | Scenario, Forecast | Plant Daniel Units 1 And 2
Loss Contingencies [Line Items]
Payments to acquire business | $	$ 1
Option to purchase, period	120 days
SOUTHERN Co GAS | Natural Gas Storage Facility
Loss Contingencies [Line Items]
Combined net book value | $		$ 438,000,000
SOUTHERN Co GAS | Natural Gas Storage Facility | Louisiana
Loss Contingencies [Line Items]
Number of facilities | Facility		2
Number of facilities to be restored | Facility		1
SOUTHERN Co GAS | Natural Gas Storage Facility | California
Loss Contingencies [Line Items]
Number of facilities | Facility		2

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Disaggregate Revenue Sources (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Disaggregation of Revenue [Line Items]
Total operating revenues	$ 5,098	$ 5,627	$ 10,510	$ 11,999
Revenue from leases	184		326
Total retail electric and gas distribution revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	4,103	4,378	8,347	9,146
Total retail electric revenues
Disaggregation of Revenue [Line Items]
Revenue from leases	8	18	16	36
Increase (decrease) in revenue from cost recovery mechanisms	(14)	68	(117)	101
Residential
Disaggregation of Revenue [Line Items]
Total operating revenues	1,488	1,579	2,776	3,118
Commercial
Disaggregation of Revenue [Line Items]
Total operating revenues	1,258	1,315	2,350	2,557
Industrial
Disaggregation of Revenue [Line Items]
Total operating revenues	763	814	1,440	1,569
Other
Disaggregation of Revenue [Line Items]
Total operating revenues	31	32	57	64
Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	562	642	1,724	1,865
Revenues not accounted for under ASC 606	5	5	8	8
Alternative revenue programs
Disaggregation of Revenue [Line Items]
Total operating revenues	1	(4)	0	(27)
Wholesale energy revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	410	464	777	937
Revenue from leases	115	118	182	187
Revenue from transactions accounted for as derivatives	30	61	82	155
Wholesale capacity revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	132	152	264	302
Revenue from leases	22	31	47	61
Other natural gas revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	126	68	439	476
Revenue from leases	8		16
Revenues not accounted for under ASC 606	10		27
Other revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	327	565	683	1,138
Revenue from leases	28	33	59	66
Revenues not accounted for under ASC 606	89	89	180	183
ALABAMA POWER CO
Disaggregation of Revenue [Line Items]
Total operating revenues	1,513	1,503	2,921	2,976
ALABAMA POWER CO | Total retail electric revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	1,378	1,338	2,592	2,624
Increase (decrease) in revenue from cost recovery mechanisms	(11)	78	(68)	125
ALABAMA POWER CO | Residential
Disaggregation of Revenue [Line Items]
Total operating revenues	588	557	1,128	1,127
ALABAMA POWER CO | Commercial
Disaggregation of Revenue [Line Items]
Total operating revenues	418	402	772	774
ALABAMA POWER CO | Industrial
Disaggregation of Revenue [Line Items]
Total operating revenues	366	372	679	710
ALABAMA POWER CO | Other
Disaggregation of Revenue [Line Items]
Total operating revenues	6	7	13	13
ALABAMA POWER CO | Wholesale energy revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	41	71	135	172
Revenue from transactions accounted for as derivatives	3	4	6	9
ALABAMA POWER CO | Wholesale capacity revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	25	25	51	49
ALABAMA POWER CO | Other revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	69	69	143	131
Revenues not accounted for under ASC 606	31	26	59	52
GEORGIA POWER CO
Disaggregation of Revenue [Line Items]
Total operating revenues	2,117	2,048	3,951	4,008
Revenue from leases	19		39
GEORGIA POWER CO | Total retail electric revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	1,946	1,889	3,614	3,688
Revenue from leases	8	18	16	36
Increase (decrease) in revenue from cost recovery mechanisms	(5)	3	(52)	12
GEORGIA POWER CO | Residential
Disaggregation of Revenue [Line Items]
Total operating revenues	831	785	1,519	1,529
GEORGIA POWER CO | Commercial
Disaggregation of Revenue [Line Items]
Total operating revenues	767	749	1,440	1,466
GEORGIA POWER CO | Industrial
Disaggregation of Revenue [Line Items]
Total operating revenues	327	335	616	650
GEORGIA POWER CO | Other
Disaggregation of Revenue [Line Items]
Total operating revenues	21	20	39	43
GEORGIA POWER CO | Wholesale energy revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	14	26	27	66
Revenue from transactions accounted for as derivatives	4	5	8	13
GEORGIA POWER CO | Wholesale capacity revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	22	13	40	27
GEORGIA POWER CO | Other revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	135	120	270	227
Revenue from leases	11	33	23	66
Revenues not accounted for under ASC 606	30	26	61	53
MISSISSIPPI POWER CO
Disaggregation of Revenue [Line Items]
Total operating revenues	313	297	600	598
Revenue from leases	2		5
MISSISSIPPI POWER CO | Total retail electric revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	215	212	418	406
Increase (decrease) in revenue from cost recovery mechanisms	2	(1)	3	(8)
MISSISSIPPI POWER CO | Residential
Disaggregation of Revenue [Line Items]
Total operating revenues	69	65	129	125
MISSISSIPPI POWER CO | Commercial
Disaggregation of Revenue [Line Items]
Total operating revenues	73	68	138	130
MISSISSIPPI POWER CO | Industrial
Disaggregation of Revenue [Line Items]
Total operating revenues	70	76	145	146
MISSISSIPPI POWER CO | Other
Disaggregation of Revenue [Line Items]
Total operating revenues	3	3	6	5
MISSISSIPPI POWER CO | Wholesale energy revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	93	77	170	176
Revenue from transactions accounted for as derivatives	1	1	1	2
MISSISSIPPI POWER CO | Wholesale capacity revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	1	1	2	5
MISSISSIPPI POWER CO | Other revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	4	7	10	11
SOUTHERN POWER CO
Disaggregation of Revenue [Line Items]
Total operating revenues	510	555	953	1,064
Revenue from leases	164		278
SOUTHERN POWER CO | Other revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	3	3	6	5
SOUTHERN POWER CO | PPA capacity revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	125	144	252	282
Revenue from leases	39	47	80	94
SOUTHERN POWER CO | PPA energy revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	291	302	518	556
Revenue from leases	125	127	198	203
SOUTHERN POWER CO | Non-PPA revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	91	106	177	221
Revenue from transactions accounted for as derivatives	22	50	67	129
SOUTHERN Co GAS
Disaggregation of Revenue [Line Items]
Total operating revenues	689	730	2,163	2,369
Revenue from leases	9		17
SOUTHERN Co GAS | Wholesale Gas Services | Third Party Gross Revenues
Disaggregation of Revenue [Line Items]
Revenue from transactions accounted for as derivatives	800	700	2,000	1,800
SOUTHERN Co GAS | Operating Segments
Disaggregation of Revenue [Line Items]
Total operating revenues	682	724	2,177	2,381
SOUTHERN Co GAS | Operating Segments | Wholesale Gas Services
Disaggregation of Revenue [Line Items]
Total operating revenues	48	(16)	134	150
SOUTHERN Co GAS | Operating Segments | Wholesale Gas Services | Third Party Gross Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	1,223	1,336	3,148	3,274
SOUTHERN Co GAS | Natural gas distribution revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	563	638	1,724	1,838
Revenues not accounted for under ASC 606	5	5	8	8
SOUTHERN Co GAS | Residential
Disaggregation of Revenue [Line Items]
Total operating revenues	229	273	830	933
SOUTHERN Co GAS | Commercial
Disaggregation of Revenue [Line Items]
Total operating revenues	65	76	235	268
SOUTHERN Co GAS | Transportation
Disaggregation of Revenue [Line Items]
Total operating revenues	213	228	469	505
SOUTHERN Co GAS | Industrial
Disaggregation of Revenue [Line Items]
Total operating revenues	5	7	22	24
SOUTHERN Co GAS | Other
Disaggregation of Revenue [Line Items]
Total operating revenues	50	58	168	135
SOUTHERN Co GAS | Alternative revenue programs
Disaggregation of Revenue [Line Items]
Total operating revenues	1	(4)	0	(27)
SOUTHERN Co GAS | Other natural gas revenues | Wholesale Gas Services | Third Party Gross Revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	1,200	1,300	3,100	3,300
SOUTHERN Co GAS | Other revenues
Disaggregation of Revenue [Line Items]
Total operating revenues	12	10	22	25
SOUTHERN Co GAS | Wholesale Gas Services
Disaggregation of Revenue [Line Items]
Total operating revenues	48	(15)	114	131
SOUTHERN Co GAS | Gas pipeline investments
Disaggregation of Revenue [Line Items]
Total operating revenues	8	8	16	16
Revenue from leases	8		16
SOUTHERN Co GAS | Gas marketing services
Disaggregation of Revenue [Line Items]
Total operating revenues	58	$ 89	287	359
Revenues not accounted for under ASC 606	$ 2		$ 11	$ 4

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Contract Balances (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Receivables	$ 2,343	$ 2,630
Contract Assets	70	102
Contract Liabilities	58	32
ALABAMA POWER CO
Disaggregation of Revenue [Line Items]
Receivables	629	520
Contract Assets	0	0
Contract Liabilities	10	12
GEORGIA POWER CO
Disaggregation of Revenue [Line Items]
Receivables	807	721
Contract Assets	30	58
Contract Liabilities	26	7
MISSISSIPPI POWER CO
Disaggregation of Revenue [Line Items]
Receivables	93	100
Contract Assets	0	0
Contract Liabilities	7	0
SOUTHERN POWER CO
Disaggregation of Revenue [Line Items]
Receivables	119	118
Contract Assets	0	0
Contract Liabilities	1	11
SOUTHERN Co GAS
Disaggregation of Revenue [Line Items]
Receivables	550	952
Contract Assets	0	0
Contract Liabilities	$ 1	$ 2

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
Disaggregation of Revenue [Line Items]
Contract assets	$ 70	$ 70	$ 102
Contract liabilities	58	58	32
Revenue from contracts with customers recognized	11	27
Unregulated Distributed Generation
Disaggregation of Revenue [Line Items]
Contract assets	32	32	39
Contract liabilities	14	14	11
ALABAMA POWER CO
Disaggregation of Revenue [Line Items]
Contract assets	0	0	0
Contract liabilities	10	10	12
Revenue from contracts with customers recognized	0	0
GEORGIA POWER CO
Disaggregation of Revenue [Line Items]
Contract assets	30	30	58
Contract liabilities	26	26	7
Revenue from contracts with customers recognized	0	0
SOUTHERN Co GAS
Disaggregation of Revenue [Line Items]
Contract assets	0	0	0
Contract liabilities	1	1	2
Revenue from contracts with customers recognized	0	0
MISSISSIPPI POWER CO
Disaggregation of Revenue [Line Items]
Contract assets	0	0	0
Contract liabilities	7	7	$ 0
Revenue, remaining performance obligation	$ 0	$ 0

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Revenue from Contracts with Customers (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers recognized	$ 11	$ 27
SOUTHERN POWER CO
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers recognized	$ 1	$ 11

Revenue from Contracts with C_7

Revenue from Contracts with Customers - Performance Obligations (Details) $ in Millions	Jun. 30, 2019USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 282
Performance obligation, expected timing of satisfaction	6 months
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 490
Performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 320
Performance obligation, expected timing of satisfaction	1 year
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 311
Performance obligation, expected timing of satisfaction	1 year
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	$ 302
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	$ 2,230
Performance obligation, expected timing of satisfaction
ALABAMA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 11
Performance obligation, expected timing of satisfaction	6 months
ALABAMA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 23
Performance obligation, expected timing of satisfaction	1 year
ALABAMA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 27
Performance obligation, expected timing of satisfaction	1 year
ALABAMA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 23
Performance obligation, expected timing of satisfaction	1 year
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	$ 22
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	$ 140
Performance obligation, expected timing of satisfaction
GEORGIA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 27
Performance obligation, expected timing of satisfaction	6 months
GEORGIA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 51
Performance obligation, expected timing of satisfaction	1 year
GEORGIA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 44
Performance obligation, expected timing of satisfaction	1 year
GEORGIA POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 31
Performance obligation, expected timing of satisfaction	1 year
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	$ 31
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	$ 83
Performance obligation, expected timing of satisfaction
MISSISSIPPI POWER CO
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 0
SOUTHERN POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2019-07-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 169
Performance obligation, expected timing of satisfaction	6 months
SOUTHERN POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 295
Performance obligation, expected timing of satisfaction	1 year
SOUTHERN POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 270
Performance obligation, expected timing of satisfaction	1 year
SOUTHERN POWER CO | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, remaining performance obligation	$ 276
Performance obligation, expected timing of satisfaction	1 year
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	$ 269
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	$ 2,154
Performance obligation, expected timing of satisfaction

Consolidated Entities and Equ_3

Consolidated Entities and Equity Method Investments - Narrative (Details) $ in Millions	May 29, 2019USD ($)	Jun. 30, 2019USD ($)investor
SOUTHERN POWER CO
Schedule of Equity Method Investments [Line Items]
Distribution made to limited partner, cash distributions paid, percentage		67.00%
Global Atlantic
Schedule of Equity Method Investments [Line Items]
Distribution made to limited partner, cash distributions paid, percentage		33.00%
Variable Interest Entity, Not Primary Beneficiary | SOUTHERN POWER CO
Schedule of Equity Method Investments [Line Items]
Carrying amount of investments		$ 144
SP Solar Holdings I, LP | Variable Interest Entity, Primary Beneficiary | SOUTHERN POWER CO
Schedule of Equity Method Investments [Line Items]
Assets		6,500
Liabilities		374
Noncontrolling interests related to other partners' interests		$ 1,100
SP Wind | SOUTHERN POWER CO
Schedule of Equity Method Investments [Line Items]
Distribution made to limited partner, cash distributions paid, percentage		60.00%
Number of financial investors | investor		3
SP Wind | Financial Investors
Schedule of Equity Method Investments [Line Items]
Distribution made to limited partner, cash distributions paid, percentage		40.00%
SP Wind | Variable Interest Entity, Primary Beneficiary | SOUTHERN POWER CO
Schedule of Equity Method Investments [Line Items]
Assets		$ 2,500
Liabilities		136
Noncontrolling interests related to other partners' interests		46
DSGP | Variable Interest Entity, Not Primary Beneficiary | SOUTHERN POWER CO
Schedule of Equity Method Investments [Line Items]
Carrying amount of investments		$ 116
Triton | SOUTHERN Co GAS
Schedule of Equity Method Investments [Line Items]
Pre tax loss on disposition of investment	$ 6
Income tax benefit on disposition of investment	13
After-tax gain on disposition of investment	$ 7

Consolidated Entities and Equ_4

Consolidated Entities and Equity Method Investments - Balance Sheet Equity Method Investment Carrying Amount (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Investment Balance	$ 1,557	$ 1,580
SOUTHERN Co GAS
Schedule of Equity Method Investments [Line Items]
Investment Balance	1,509	1,538
SOUTHERN Co GAS | SNG
Schedule of Equity Method Investments [Line Items]
Investment Balance	1,243	1,261
SOUTHERN Co GAS | Atlantic Coast Pipeline
Schedule of Equity Method Investments [Line Items]
Investment Balance	101	83
SOUTHERN Co GAS | PennEast Pipeline
Schedule of Equity Method Investments [Line Items]
Investment Balance	77	71
SOUTHERN Co GAS | Other
Schedule of Equity Method Investments [Line Items]
Investment Balance	$ 88	$ 123

Consolidated Entities and Equ_5

Consolidated Entities and Equity Method Investments - Income Statement Equity Method Investment Carrying Amount (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Schedule of Equity Method Investments [Line Items]
Earnings from Equity Method Investments	$ 33	$ 31	$ 81	$ 72
SOUTHERN Co GAS
Schedule of Equity Method Investments [Line Items]
Earnings from Equity Method Investments	31	31	80	74
SOUTHERN Co GAS | SNG
Schedule of Equity Method Investments [Line Items]
Earnings from Equity Method Investments	32	27	74	66
SOUTHERN Co GAS | Atlantic Coast Pipeline
Schedule of Equity Method Investments [Line Items]
Earnings from Equity Method Investments	3	1	6	3
SOUTHERN Co GAS | PennEast Pipeline
Schedule of Equity Method Investments [Line Items]
Earnings from Equity Method Investments	1	1	3	2
SOUTHERN Co GAS | Other
Schedule of Equity Method Investments [Line Items]
Earnings from Equity Method Investments	$ (5)	$ 2	$ (3)	$ 3

Consolidated Entities and Equ_6

Consolidated Entities and Equity Method Investments - Investment in SNG (Details) - SNG - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Income Statement Information
Revenues	$ 155	$ 146	$ 321	$ 306
Operating income	86	60	192	159
Net income	$ 64	$ 54	$ 148	$ 132

Financing - Narrative (Details)

Financing - Narrative (Details)	1 Months Ended				3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2019USD ($)loan	May 31, 2019USD ($)	Mar. 31, 2019USD ($)	Jan. 31, 2019USD ($)	Jun. 30, 2019USD ($)shares	Jun. 30, 2018shares	Jun. 30, 2019USD ($)loanshares	Jun. 30, 2018USD ($)shares	Dec. 31, 2014	Apr. 30, 2019USD ($)	Aug. 31, 2018
Debt Instrument [Line Items]
Variable rate pollution control revenue bonds outstanding	$ 1,400,000,000				$ 1,400,000,000		$ 1,400,000,000
Fixed rate pollution control revenue bonds outstanding	272,000,000				272,000,000		272,000,000
Borrowing capacity	7,583,000,000				$ 7,583,000,000		7,583,000,000
Repayments of short-term debt							$ 1,850,000,000	$ 550,000,000
Stock-based compensation awards not included in the diluted earnings per share calculation because they were anti-dilutive (in shares) | shares					0	5,300,000	0	0
Senior Notes
Debt Instrument [Line Items]
Repayments of debt				$ 1,200,000,000
Senior Notes | 1.85% Notes
Debt Instrument [Line Items]
Interest rate				1.85%
Repurchase amount				$ 522,000,000
Debt face amount				$ 1,000,000,000
Senior Notes | Series 2014B Notes
Debt Instrument [Line Items]
Interest rate				2.15%
Repurchase amount				$ 180,000,000
Debt face amount				350,000,000
Senior Notes | Series 2018A Notes
Debt Instrument [Line Items]
Repurchase amount				504,000,000
Debt face amount				750,000,000
Notes Payable to Banks | Uncommitted Bank Credit Arrangement
Debt Instrument [Line Items]
Repayments of short-term debt				250,000,000
Notes Payable to Banks | Floating Rate Bank Term Loan Agreement
Debt Instrument [Line Items]
Repayments of short-term debt				1,500,000,000
ALABAMA POWER CO
Debt Instrument [Line Items]
Variable rate pollution control revenue bonds outstanding	854,000,000				$ 854,000,000		$ 854,000,000
Fixed rate pollution control revenue bonds outstanding	87,000,000				87,000,000		87,000,000
Borrowing capacity	1,303,000,000				1,303,000,000		1,303,000,000
GEORGIA POWER CO
Debt Instrument [Line Items]
Variable rate pollution control revenue bonds outstanding	550,000,000				550,000,000		550,000,000
Fixed rate pollution control revenue bonds outstanding	185,000,000				185,000,000		185,000,000
Borrowing capacity	1,750,000,000				1,750,000,000		1,750,000,000
Repayments of short-term debt							0	$ 150,000,000
GEORGIA POWER CO | Municipal bonds | Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project) First Series 1992
Debt Instrument [Line Items]
Redeemed aggregate principal amount				13,000,000
GEORGIA POWER CO | Municipal bonds | Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Eighth Series 1994
Debt Instrument [Line Items]
Redeemed aggregate principal amount				20,000,000
GEORGIA POWER CO | Municipal bonds | Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Second Series 1995
Debt Instrument [Line Items]
Redeemed aggregate principal amount				$ 75,000,000
GEORGIA POWER CO | Municipal bonds | Development Authority of Bartow County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Bowen Project), First Series 2009
Debt Instrument [Line Items]
Debt face amount			$ 173,000,000
GEORGIA POWER CO | Municipal bonds | Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), First Series 2013
Debt Instrument [Line Items]
Debt face amount			105,000,000
GEORGIA POWER CO | Municipal bonds | Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Second Series 2008
Debt Instrument [Line Items]
Debt face amount			65,000,000
GEORGIA POWER CO | Municipal bonds | Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Fourth Series 1994
Debt Instrument [Line Items]
Debt face amount										$ 55,000,000
GEORGIA POWER CO | Municipal bonds | Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Fourth Series 1995
Debt Instrument [Line Items]
Debt face amount										30,000,000
GEORGIA POWER CO | Municipal bonds | Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Ninth Series 1994
Debt Instrument [Line Items]
Debt face amount										20,000,000
GEORGIA POWER CO | Municipal bonds | Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Second Series 1994
Debt Instrument [Line Items]
Debt face amount										10,000,000
GEORGIA POWER CO | Municipal bonds | Development Authority of Burke County (Georgia) Pollution Control Revenue Bonds (Georgia Power Company Plant Vogtle Project), Fifth Series 1994
Debt Instrument [Line Items]
Debt face amount	$ 55,000,000				55,000,000		55,000,000
GEORGIA POWER CO | Plant Vogtle Units 3 And 4
Debt Instrument [Line Items]
Undivided ownership interest									45.70%
GEORGIA POWER CO | Notes Payable to Banks
Debt Instrument [Line Items]
Number of short-term loans | loan	2
GEORGIA POWER CO | Notes Payable to Banks | First Short-Term Floating Rate Bank Loan
Debt Instrument [Line Items]
Debt face amount	$ 125,000,000				125,000,000		125,000,000
GEORGIA POWER CO | Notes Payable to Banks | Second Short-Term Floating Rate Bank Loan
Debt Instrument [Line Items]
Debt face amount	125,000,000				125,000,000		$ 125,000,000
GEORGIA POWER CO | Term Loan
Debt Instrument [Line Items]
Number of term loan facilities | loan							2
GEORGIA POWER CO | 2014 FFB Credit Facility
Debt Instrument [Line Items]
Eligible project costs to be reimbursed							$ 5,130,000,000
Eligible project costs to be reimbursed, percentage									70.00%
Borrowings made			$ 835,000,000
Interest rate			3.213%
Borrowings outstanding	3,460,000,000				3,460,000,000		3,460,000,000
Amortization period for line of credit facility									5 years
GEORGIA POWER CO | 2014 FFB Credit Facility | U.S. Treasury Rate
Debt Instrument [Line Items]
Basis spread									0.375%
GEORGIA POWER CO | Additional FFB Credit Facility
Debt Instrument [Line Items]
Eligible project costs to be reimbursed, percentage			70.00%
Amounts received under Guarantee Settlement Agreement, less Customer Refunds			$ 1,492,000,000
MISSISSIPPI POWER CO
Debt Instrument [Line Items]
Variable rate pollution control revenue bonds outstanding	40,000,000				40,000,000		40,000,000
Borrowing capacity	150,000,000				150,000,000		150,000,000
Repayments of short-term debt							0	200,000,000
MISSISSIPPI POWER CO | Municipal bonds | Mississippi Business Finance Corporation Pollution Control Revenue Refunding Bonds, Series 2002
Debt Instrument [Line Items]
Debt face amount			$ 43,000,000
MISSISSIPPI POWER CO | Credit Arrangement
Debt Instrument [Line Items]
Borrowing capacity	50,000,000				50,000,000		50,000,000
SOUTHERN Co GAS
Debt Instrument [Line Items]
Borrowing capacity	1,750,000,000				1,750,000,000		1,750,000,000
SOUTHERN POWER CO
Debt Instrument [Line Items]
Borrowing capacity	600,000,000	$ 600,000,000			600,000,000		600,000,000			750,000,000
Repayments of short-term debt							100,000,000	$ 0
SOUTHERN POWER CO | Notes Payable to Banks
Debt Instrument [Line Items]
Repayments of short-term debt		100,000,000
Southern Company Gas Capital
Debt Instrument [Line Items]
Borrowing capacity	1,250,000,000	$ 1,750,000,000			1,250,000,000		1,250,000,000			$ 1,900,000,000
Nicor Gas
Debt Instrument [Line Items]
Borrowing capacity	$ 500,000,000				$ 500,000,000		$ 500,000,000
Plant Vogtle Units 3 And 4 | GEORGIA POWER CO
Debt Instrument [Line Items]
Undivided ownership interest	45.70%				45.70%		45.70%
Failure to vote, percentage of ownership interests									90.00%		90.00%

Financing - Schedule of Credit

Financing - Schedule of Credit Arrangements (Details) - USD ($)	Jun. 30, 2019	May 31, 2019	Apr. 30, 2019
Line of Credit Facility [Line Items]
Expires, 2019	$ 3,000,000
Expires, 2020	530,000,000
Expires, 2022	150,000,000
Expires, 2024	6,900,000,000
Total	7,583,000,000
Unused	7,524,000,000
Due within One Year No Term Out	33,000,000
Southern Company
Line of Credit Facility [Line Items]
Expires, 2019	0
Expires, 2020	0
Expires, 2022	0
Expires, 2024	2,000,000,000
Total	2,000,000,000
Unused	1,999,000,000
Due within One Year No Term Out	0
ALABAMA POWER CO
Line of Credit Facility [Line Items]
Expires, 2019	3,000,000
Expires, 2020	500,000,000
Expires, 2022	0
Expires, 2024	800,000,000
Total	1,303,000,000
Unused	1,303,000,000
Due within One Year No Term Out	3,000,000
GEORGIA POWER CO
Line of Credit Facility [Line Items]
Expires, 2019	0
Expires, 2020	0
Expires, 2022	0
Expires, 2024	1,750,000,000
Total	1,750,000,000
Unused	1,736,000,000
Due within One Year No Term Out	0
MISSISSIPPI POWER CO
Line of Credit Facility [Line Items]
Expires, 2019	0
Expires, 2020	0
Expires, 2022	150,000,000
Expires, 2024	0
Total	150,000,000
Unused	150,000,000
Due within One Year No Term Out	0
SOUTHERN POWER CO
Line of Credit Facility [Line Items]
Expires, 2019	0
Expires, 2020	0
Expires, 2022	0
Expires, 2024	600,000,000
Total	600,000,000	$ 600,000,000	$ 750,000,000
Unused	561,000,000
Due within One Year No Term Out	0
SOUTHERN POWER CO | Standby Letters of Credit
Line of Credit Facility [Line Items]
Total	120,000,000
Unused	30,000,000
SOUTHERN Co GAS
Line of Credit Facility [Line Items]
Expires, 2019	0
Expires, 2020	0
Expires, 2022	0
Expires, 2024	1,750,000,000
Total	1,750,000,000
Unused	1,745,000,000
Due within One Year No Term Out	0
Other
Line of Credit Facility [Line Items]
Expires, 2019	0
Expires, 2020	30,000,000
Expires, 2022	0
Expires, 2024	0
Total	30,000,000
Unused	30,000,000
Due within One Year No Term Out	30,000,000
Southern Company Gas Capital
Line of Credit Facility [Line Items]
Total	1,250,000,000	$ 1,750,000,000	$ 1,900,000,000
Nicor Gas
Line of Credit Facility [Line Items]
Total	$ 500,000,000

Financing - Schedule of Long-Te

Financing - Schedule of Long-Term Debt Financing Activities (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Debt Instrument [Line Items]
Senior Note Maturities, Redemptions, and Repurchases	$ 2,300
Revenue Bond Issuances and Reofferings of Purchased Bonds	556
Revenue Bond Maturities, Redemptions, and Repurchases	248
Other Long-Term Debt Issuances	835
Other Long-Term Debt Redemptions and Maturities	12
Southern Company
Debt Instrument [Line Items]
Senior Note Maturities, Redemptions, and Repurchases	2,100
Revenue Bond Issuances and Reofferings of Purchased Bonds	0
Revenue Bond Maturities, Redemptions, and Repurchases	0
Other Long-Term Debt Issuances	0
Other Long-Term Debt Redemptions and Maturities	0
ALABAMA POWER CO
Debt Instrument [Line Items]
Senior Note Maturities, Redemptions, and Repurchases	200
Revenue Bond Issuances and Reofferings of Purchased Bonds	0
Revenue Bond Maturities, Redemptions, and Repurchases	0
Other Long-Term Debt Issuances	0
Other Long-Term Debt Redemptions and Maturities	0
GEORGIA POWER CO
Debt Instrument [Line Items]
Senior Note Maturities, Redemptions, and Repurchases	0
Revenue Bond Issuances and Reofferings of Purchased Bonds	513
Revenue Bond Maturities, Redemptions, and Repurchases	223
Other Long-Term Debt Issuances	835
Other Long-Term Debt Redemptions and Maturities	3
MISSISSIPPI POWER CO
Debt Instrument [Line Items]
Senior Note Maturities, Redemptions, and Repurchases	0
Revenue Bond Issuances and Reofferings of Purchased Bonds	43
Revenue Bond Maturities, Redemptions, and Repurchases	0
Other Long-Term Debt Issuances	0
Other Long-Term Debt Redemptions and Maturities	0
Other
Debt Instrument [Line Items]
Senior Note Maturities, Redemptions, and Repurchases	0
Revenue Bond Issuances and Reofferings of Purchased Bonds	0
Revenue Bond Maturities, Redemptions, and Repurchases	25
Other Long-Term Debt Issuances	0
Other Long-Term Debt Redemptions and Maturities	$ 9

Financing - Shares Used to Comp

Financing - Shares Used to Compute Diluted Earnings Per Share (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Debt Disclosure [Abstract]
As reported shares	1,044	1,014	1,041	1,012
Effect of stock-based compensation	8	0	8	5
Diluted shares	1,052	1,014	1,049	1,017

Income Taxes (Details)

Income Taxes (Details) - USD ($) $ in Billions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Income Tax Contingency [Line Items]
Effective tax (benefit) rate	33.50%	(3.20%)
GEORGIA POWER CO
Income Tax Contingency [Line Items]
Effective tax (benefit) rate	21.70%	(53.50%)
MISSISSIPPI POWER CO
Income Tax Contingency [Line Items]
Effective tax (benefit) rate	14.00%	18.70%
SOUTHERN POWER CO
Income Tax Contingency [Line Items]
Effective tax (benefit) rate	(35.50%)	(1386.50%)
SOUTHERN Co GAS
Income Tax Contingency [Line Items]
Effective tax (benefit) rate	18.00%	39.10%
Investment Tax Credit Carryforward
Income Tax Contingency [Line Items]
Federal ITC/PTC carryforward	$ 2		$ 2.4

Retirement Benefits (Details)

Retirement Benefits (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Amortization:
Net (gain)/loss
Pension Plans
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, expected future employer contributions, remainder of fiscal year	$ 0		$ 0
Pension Plans and Postretirement Plans
Service cost	73,000,000	89,000,000	146,000,000	$ 179,000,000
Interest cost	123,000,000	116,000,000	246,000,000	232,000,000
Expected return on plan assets	(221,000,000)	(235,000,000)	(442,000,000)	(471,000,000)
Amortization:
Prior service costs	1,000,000	1,000,000	1,000,000	2,000,000
Regulatory asset	0	0	0	0
Net (gain)/loss	30,000,000	54,000,000	60,000,000	107,000,000
Net periodic pension cost (income)	6,000,000	25,000,000	11,000,000	49,000,000
Pension Plans | ALABAMA POWER CO
Pension Plans and Postretirement Plans
Service cost	17,000,000	20,000,000	34,000,000	39,000,000
Interest cost	29,000,000	25,000,000	57,000,000	50,000,000
Expected return on plan assets	(52,000,000)	(53,000,000)	(103,000,000)	(104,000,000)
Amortization:
Prior service costs	1,000,000	1,000,000	1,000,000	1,000,000
Regulatory asset	0	0	0	0
Net (gain)/loss	9,000,000	13,000,000	18,000,000	27,000,000
Net periodic pension cost (income)	4,000,000	6,000,000	7,000,000	13,000,000
Pension Plans | GEORGIA POWER CO
Pension Plans and Postretirement Plans
Service cost	18,000,000	21,000,000	37,000,000	43,000,000
Interest cost	39,000,000	35,000,000	78,000,000	70,000,000
Expected return on plan assets	(73,000,000)	(74,000,000)	(146,000,000)	(148,000,000)
Amortization:
Prior service costs	1,000,000	1,000,000	1,000,000	1,000,000
Regulatory asset	0	0	0	0
Net (gain)/loss	11,000,000	17,000,000	22,000,000	34,000,000
Net periodic pension cost (income)	(4,000,000)	0	(8,000,000)	0
Pension Plans | MISSISSIPPI POWER CO
Pension Plans and Postretirement Plans
Service cost	3,000,000	4,000,000	6,000,000	8,000,000
Interest cost	5,000,000	5,000,000	11,000,000	10,000,000
Expected return on plan assets	(10,000,000)	(10,000,000)	(20,000,000)	(20,000,000)
Amortization:
Prior service costs	0	0	0	0
Regulatory asset	0	0	0	0
Net (gain)/loss	2,000,000	2,000,000	3,000,000	5,000,000
Net periodic pension cost (income)	0	1,000,000	0	3,000,000
Pension Plans | SOUTHERN POWER CO
Pension Plans and Postretirement Plans
Service cost	1,000,000	2,000,000	3,000,000	4,000,000
Interest cost	2,000,000	2,000,000	3,000,000	3,000,000
Expected return on plan assets	(3,000,000)	(2,000,000)	(5,000,000)	(5,000,000)
Amortization:
Prior service costs	0	0	0	0
Regulatory asset	0	0	0	0
Net (gain)/loss	0	0	0	1,000,000
Net periodic pension cost (income)	0	2,000,000	1,000,000	3,000,000
Pension Plans | SOUTHERN Co GAS
Pension Plans and Postretirement Plans
Service cost	6,000,000	8,000,000	12,000,000	16,000,000
Interest cost	9,000,000	9,000,000	18,000,000	19,000,000
Expected return on plan assets	(15,000,000)	(17,000,000)	(30,000,000)	(35,000,000)
Amortization:
Prior service costs	0	0	(1,000,000)	(1,000,000)
Regulatory asset	4,000,000	4,000,000	7,000,000	7,000,000
Net (gain)/loss	0	3,000,000	1,000,000	6,000,000
Net periodic pension cost (income)	4,000,000	7,000,000	7,000,000	12,000,000
Postretirement Benefits
Pension Plans and Postretirement Plans
Service cost	4,000,000	6,000,000	9,000,000	12,000,000
Interest cost	17,000,000	18,000,000	34,000,000	37,000,000
Expected return on plan assets	(17,000,000)	(17,000,000)	(33,000,000)	(34,000,000)
Amortization:
Prior service costs	1,000,000	1,000,000	2,000,000	3,000,000
Regulatory asset	0	0	0	0
Net (gain)/loss	0	4,000,000	(1,000,000)	7,000,000
Net periodic pension cost (income)	5,000,000	12,000,000	11,000,000	25,000,000
Postretirement Benefits | ALABAMA POWER CO
Pension Plans and Postretirement Plans
Service cost	1,000,000	2,000,000	2,000,000	3,000,000
Interest cost	4,000,000	4,000,000	8,000,000	8,000,000
Expected return on plan assets	(7,000,000)	(7,000,000)	(13,000,000)	(13,000,000)
Amortization:
Prior service costs	1,000,000	1,000,000	2,000,000	2,000,000
Regulatory asset	0	0	0	0
Net (gain)/loss	0	1,000,000	0	1,000,000
Net periodic pension cost (income)	(1,000,000)	1,000,000	(1,000,000)	1,000,000
Postretirement Benefits | GEORGIA POWER CO
Pension Plans and Postretirement Plans
Service cost	1,000,000	1,000,000	2,000,000	3,000,000
Interest cost	6,000,000	7,000,000	13,000,000	14,000,000
Expected return on plan assets	(6,000,000)	(7,000,000)	(12,000,000)	(13,000,000)
Amortization:
Prior service costs	0	1,000,000	0	1,000,000
Regulatory asset	0	0	0	0
Net (gain)/loss	0	2,000,000	0	4,000,000
Net periodic pension cost (income)	1,000,000	4,000,000	3,000,000	9,000,000
Postretirement Benefits | MISSISSIPPI POWER CO
Pension Plans and Postretirement Plans
Service cost	0	1,000,000	0	1,000,000
Interest cost	1,000,000	1,000,000	2,000,000	2,000,000
Expected return on plan assets	(1,000,000)	(1,000,000)	(1,000,000)	(1,000,000)
Amortization:
Prior service costs	0	0	0	0
Regulatory asset	0	0	0	0
Net (gain)/loss	0	0	0	0
Net periodic pension cost (income)	0	1,000,000	1,000,000	2,000,000
Postretirement Benefits | SOUTHERN POWER CO
Pension Plans and Postretirement Plans
Service cost	0	0	0	0
Interest cost	0	0	0	0
Expected return on plan assets	0	0	0	0
Amortization:
Prior service costs	0	0	0	0
Regulatory asset	0	0	0	0
Net (gain)/loss	0	0	0	0
Net periodic pension cost (income)	0	0	0	0
Postretirement Benefits | SOUTHERN Co GAS
Pension Plans and Postretirement Plans
Service cost	0	0	1,000,000	1,000,000
Interest cost	3,000,000	3,000,000	5,000,000	5,000,000
Expected return on plan assets	(1,000,000)	(2,000,000)	(3,000,000)	(4,000,000)
Amortization:
Prior service costs	0	0	0	0
Regulatory asset	1,000,000	2,000,000	3,000,000	3,000,000
Net (gain)/loss	(1,000,000)	0	(2,000,000)	0
Net periodic pension cost (income)	$ 2,000,000	$ 3,000,000	$ 4,000,000	$ 5,000,000

Fair Value Measurements - Asset

Fair Value Measurements - Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Assets:
Derivatives	$ 191	$ 313
Liabilities:
Derivatives	185	235
Collateral already posted, aggregate fair value	178
ALABAMA POWER CO
Assets:
Derivatives	3	2
Liabilities:
Derivatives	15	6
GEORGIA POWER CO
Assets:
Derivatives	0	0
Investments in trusts	30
Liabilities:
Derivatives	74	17
MISSISSIPPI POWER CO
Assets:
Derivatives	0	1
Liabilities:
Derivatives	16	7
SOUTHERN POWER CO
Assets:
Derivatives	61	76
Liabilities:
Derivatives	26	28
SOUTHERN Co GAS
Assets:
Derivatives	127	233
Liabilities:
Derivatives	39	124
Collateral already posted, aggregate fair value	178	$ 277
Fair Value, Measurements, Recurring
Assets:
Cash equivalents	846
Other investments	26
Total	3,361
Liabilities:
Contingent consideration	21
Total	712
Fair Value, Measurements, Recurring | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	841
Other investments	9
Total	1,936
Liabilities:
Contingent consideration	0
Total	405
Fair Value, Measurements, Recurring | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	5
Other investments	17
Total	1,359
Liabilities:
Contingent consideration	0
Total	264
Fair Value, Measurements, Recurring | Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0
Other investments	0
Total	12
Liabilities:
Contingent consideration	21
Total	43
Fair Value, Measurements, Recurring | Net Asset Value as a Practical Expedient (NAV)
Assets:
Total	54
Fair Value, Measurements, Recurring | Energy-related derivatives
Assets:
Derivatives	459
Liabilities:
Derivatives	616
Fair Value, Measurements, Recurring | Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivatives	270
Liabilities:
Derivatives	405
Fair Value, Measurements, Recurring | Energy-related derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	177
Liabilities:
Derivatives	189
Fair Value, Measurements, Recurring | Energy-related derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	12
Liabilities:
Derivatives	22
Fair Value, Measurements, Recurring | Foreign currency derivatives
Assets:
Derivatives	60
Liabilities:
Derivatives	23
Fair Value, Measurements, Recurring | Foreign currency derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | Foreign currency derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	60
Liabilities:
Derivatives	23
Fair Value, Measurements, Recurring | Foreign currency derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | Interest rate derivatives
Liabilities:
Derivatives	52
Fair Value, Measurements, Recurring | Interest rate derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | Interest rate derivatives | Significant Other Observable Inputs (Level 2)
Liabilities:
Derivatives	52
Fair Value, Measurements, Recurring | Interest rate derivatives | Significant Unobservable Inputs (Level 3)
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | Domestic equity
Assets:
Investments in trusts	827
Fair Value, Measurements, Recurring | Domestic equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	703
Fair Value, Measurements, Recurring | Domestic equity | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	124
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	268
Fair Value, Measurements, Recurring | Foreign equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	62
Fair Value, Measurements, Recurring | Foreign equity | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	206
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	307
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	307
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	72
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	72
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	16
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	16
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	322
Fair Value, Measurements, Recurring | Corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	23
Fair Value, Measurements, Recurring | Corporate bonds | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	299
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	74
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	74
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	54
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	54
Fair Value, Measurements, Recurring | Cash and cash equivalents
Assets:
Investments in trusts	1
Fair Value, Measurements, Recurring | Cash and cash equivalents | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	1
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	29
Fair Value, Measurements, Recurring | Other | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	27
Fair Value, Measurements, Recurring | Other | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	2
Fair Value, Measurements, Recurring | Other | Significant Unobservable Inputs (Level 3)
Assets:
Investments in trusts	0
Fair Value, Measurements, Recurring | ALABAMA POWER CO
Assets:
Cash equivalents	435
Other investments	17
Total	1,421
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	430
Other investments	0
Total	978
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	5
Other investments	17
Total	389
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	54
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Energy-related derivatives
Assets:
Derivatives	6
Liabilities:
Derivatives	18
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	6
Liabilities:
Derivatives	18
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	569
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Domestic equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	456
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Domestic equity | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	113
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	122
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Foreign equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	62
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Foreign equity | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	60
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	1
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	1
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	164
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Corporate bonds | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	23
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Corporate bonds | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	141
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	25
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	25
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	54
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	54
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Other
Assets:
Investments in trusts	7
Fair Value, Measurements, Recurring | ALABAMA POWER CO | Other | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	7
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	984
Liabilities:
Total	80
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total	267
Liabilities:
Total	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Other Observable Inputs (Level 2)
Assets:
Total	717
Liabilities:
Total	80
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Significant Unobservable Inputs (Level 3)
Assets:
Total	0
Liabilities:
Total	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Energy-related derivatives
Assets:
Derivatives	6
Liabilities:
Derivatives	43
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	6
Liabilities:
Derivatives	43
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
Liabilities:
Derivatives	37
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Interest rate derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Interest rate derivatives | Significant Other Observable Inputs (Level 2)
Liabilities:
Derivatives	37
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Interest rate derivatives | Significant Unobservable Inputs (Level 3)
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Domestic equity
Assets:
Investments in trusts	248
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Domestic equity | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	247
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	143
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	143
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	286
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	286
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	71
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	71
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	158
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	158
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	50
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	50
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	22
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Other | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Investments in trusts	20
Fair Value, Measurements, Recurring | GEORGIA POWER CO | Other | Significant Other Observable Inputs (Level 2)
Assets:
Investments in trusts	2
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
Assets:
Cash equivalents	170
Total	173
Fair Value, Measurements, Recurring | MISSISSIPPI POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	170
Total	170
Fair Value, Measurements, Recurring | MISSISSIPPI POWER CO | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	0
Total	3
Fair Value, Measurements, Recurring | MISSISSIPPI POWER CO | Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0
Total	0
Fair Value, Measurements, Recurring | MISSISSIPPI POWER CO | Energy-related derivatives
Assets:
Derivatives	3
Liabilities:
Derivatives	19
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	3
Liabilities:
Derivatives	19
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
Assets:
Cash equivalents	177
Total	239
Liabilities:
Contingent consideration	21
Total	48
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Cash equivalents	177
Total	177
Liabilities:
Contingent consideration	0
Total	0
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Significant Other Observable Inputs (Level 2)
Assets:
Cash equivalents	0
Total	62
Liabilities:
Contingent consideration	0
Total	27
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Significant Unobservable Inputs (Level 3)
Assets:
Cash equivalents	0
Total	0
Liabilities:
Contingent consideration	21
Total	21
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Energy-related derivatives
Assets:
Derivatives	2
Liabilities:
Derivatives	4
Fair Value, Measurements, Recurring | SOUTHERN 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 | SOUTHERN POWER CO | Energy-related derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	2
Liabilities:
Derivatives	4
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Energy-related derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Foreign currency derivatives
Assets:
Derivatives	60
Liabilities:
Derivatives	23
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Foreign currency derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Foreign currency derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	60
Liabilities:
Derivatives	23
Fair Value, Measurements, Recurring | SOUTHERN POWER CO | Foreign currency derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	0
Liabilities:
Derivatives	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS
Assets:
Total	473
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Total	271
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Other Observable Inputs (Level 2)
Assets:
Total	190
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Significant Unobservable Inputs (Level 3)
Assets:
Total	12
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Energy-related derivatives
Assets:
Derivatives	442
Liabilities:
Derivatives	532
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Energy-related derivatives | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Derivatives	270
Liabilities:
Derivatives	405
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Energy-related derivatives | Significant Other Observable Inputs (Level 2)
Assets:
Derivatives	160
Liabilities:
Derivatives	105
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Energy-related derivatives | Significant Unobservable Inputs (Level 3)
Assets:
Derivatives	12
Liabilities:
Derivatives	22
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Domestic equity
Assets:
Non-qualified deferred compensation trusts	10
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	10
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	4
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	4
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	16
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	16
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 and cash equivalents
Assets:
Non-qualified deferred compensation trusts	1
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Cash and cash equivalents | Quoted Prices in Active Markets for Identical Assets (Level 1)
Assets:
Non-qualified deferred compensation trusts	1
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Cash and cash equivalents | Significant Other Observable Inputs (Level 2)
Assets:
Non-qualified deferred compensation trusts	0
Fair Value, Measurements, Recurring | SOUTHERN Co GAS | Cash and cash equivalents | Significant Unobservable Inputs (Level 3)
Assets:
Non-qualified deferred compensation trusts	$ 0

Fair Value Measurements - Sched

Fair Value Measurements - Schedule of Increase (Decrease) In Fair Value Of Funds (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Fair Value, Option, Quantitative Disclosures [Line Items]
Increase (decrease) in fair value of funds	$ 75	$ 14	$ 227	$ 4
ALABAMA POWER CO
Fair Value, Option, Quantitative Disclosures [Line Items]
Increase (decrease) in fair value of funds	38	15	125	10
GEORGIA POWER CO
Fair Value, Option, Quantitative Disclosures [Line Items]
Increase (decrease) in fair value of funds	$ 37	$ (1)	$ 102	$ (6)

Fair Value Measurements - Narra

Fair Value Measurements - Narrative (Details) $ in Millions	Jun. 30, 2019USD ($)$ / MMBTU
ALABAMA POWER CO | Private equity
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair value	$ 54
Unfunded commitments	45
SOUTHERN Co GAS | Significant Unobservable Inputs (Level 3) | Energy-related derivatives
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Fair value of derivatives	$ (10)
SOUTHERN Co GAS | Significant Unobservable Inputs (Level 3) | Energy-related derivatives | Forward Price | Valuation, Market Approach | Minimum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Measurement input (usd per mmbtu) | $ / MMBTU	0.09
SOUTHERN Co GAS | Significant Unobservable Inputs (Level 3) | Energy-related derivatives | Forward Price | Valuation, Market Approach | Maximum
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Measurement input (usd per mmbtu) | $ / MMBTU	1.39

Fair Value Measurements - Finan

Fair Value Measurements - Financial Instruments for which Carrying Amount did not Equal Fair Value (Details) $ in Millions	Jun. 30, 2019USD ($)
Long-term debt, including securities due within one year:
Carrying amount	$ 42,596
Fair value	45,394
ALABAMA POWER CO
Long-term debt, including securities due within one year:
Carrying amount	7,922
Fair value	8,717
GEORGIA POWER CO
Long-term debt, including securities due within one year:
Carrying amount	10,969
Fair value	11,749
MISSISSIPPI POWER CO
Long-term debt, including securities due within one year:
Carrying amount	1,618
Fair value	1,657
SOUTHERN POWER CO
Long-term debt, including securities due within one year:
Carrying amount	5,011
Fair value	5,261
SOUTHERN Co GAS
Long-term debt, including securities due within one year:
Carrying amount	5,916
Fair value	$ 6,420

Fair Value Measurements - Fair

Fair Value Measurements - Fair Value of Commodity Derivative Contracts that Include a Significant Unobservable Component (Details) - SOUTHERN Co GAS - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ (19)	$ 0
Transfers to Level 3	(3)	(33)
Changes in fair value	12	23
Ending balance	$ (10)	$ (10)

Derivatives - Energy-Related an

Derivatives - Energy-Related and Interest Rate Derivatives (Details) MMBTU in Millions, $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)MMBTU
Energy-related, Natural Gas
Energy-related derivative contracts
Net Purchased mmBtu | MMBTU	536
Interest rate derivatives
Interest rate derivatives
Notional Amount	$ 3,000
Fair Value Gain (Loss) at June 30, 2019	$ (53)
ALABAMA POWER CO | Energy-related, Natural Gas
Energy-related derivative contracts
Net Purchased mmBtu | MMBTU	88
GEORGIA POWER CO | Energy-related, Natural Gas
Energy-related derivative contracts
Net Purchased mmBtu | MMBTU	200
GEORGIA POWER CO | Interest rate derivatives | March 2025 | Cash Flow Hedges of Forecasted Debt
Interest rate derivatives
Notional Amount	$ 250
Weighted Average Interest Rate Paid	2.23%
Fair Value Gain (Loss) at June 30, 2019	$ (6)
GEORGIA POWER CO | Interest rate derivatives | September 2029 | Cash Flow Hedges of Forecasted Debt
Interest rate derivatives
Notional Amount	$ 250
Weighted Average Interest Rate Paid	2.39%
Fair Value Gain (Loss) at June 30, 2019	$ (10)
GEORGIA POWER CO | Interest rate derivatives | March 2030 | Cash Flow Hedges of Forecasted Debt
Interest rate derivatives
Notional Amount	$ 250
Weighted Average Interest Rate Paid	2.40%
Fair Value Gain (Loss) at June 30, 2019	$ (9)
GEORGIA POWER CO | Interest rate derivatives | February 2044 | Cash Flow Hedges of Forecasted Debt
Interest rate derivatives
Notional Amount	$ 250
Weighted Average Interest Rate Paid	2.48%
Fair Value Gain (Loss) at June 30, 2019	$ (12)
GEORGIA POWER CO | Interest rate derivatives | December 2019 | Fair Value Hedges of Existing Debt
Interest rate derivatives
Notional Amount	$ 200
Interest Rate Received	4.25%
Fair Value Gain (Loss) at June 30, 2019	$ (1)
GEORGIA POWER CO | LIBOR | Interest rate derivatives | December 2019 | Fair Value Hedges of Existing Debt
Interest rate derivatives
Weighted Average Interest Rate Paid	2.46%
MISSISSIPPI POWER CO | Energy-related, Natural Gas
Energy-related derivative contracts
Net Purchased mmBtu | MMBTU	101
SOUTHERN POWER CO | Energy-related, Natural Gas
Energy-related derivative contracts
Net Purchased mmBtu | MMBTU	8
SOUTHERN Co GAS | Energy-related, Natural Gas
Energy-related derivative contracts
Net Purchased mmBtu | MMBTU	139
SOUTHERN Co GAS | Energy-related, Natural Gas | Derivatives not designated as hedging instruments | Long
Energy-related derivative contracts
Derivative nonmonetary notional amount net long short position volume | MMBTU	4,000
SOUTHERN Co GAS | Energy-related, Natural Gas | Derivatives not designated as hedging instruments | Short
Energy-related derivative contracts
Derivative nonmonetary notional amount net long short position volume | MMBTU	3,900
Southern Company | Interest rate derivatives | June 2020 | Fair Value Hedges of Existing Debt
Interest rate derivatives
Notional Amount	$ 300
Interest Rate Received	2.75%
Fair Value Gain (Loss) at June 30, 2019	$ (1)
Southern Company | Interest rate derivatives | July 2021 | Fair Value Hedges of Existing Debt
Interest rate derivatives
Notional Amount	$ 1,500
Interest Rate Received	2.35%
Fair Value Gain (Loss) at June 30, 2019	$ (14)
Southern Company | LIBOR | Interest rate derivatives | June 2020 | Fair Value Hedges of Existing Debt
Interest rate derivatives
Weighted Average Interest Rate Paid	0.92%
Southern Company | LIBOR | Interest rate derivatives | July 2021 | Fair Value Hedges of Existing Debt
Interest rate derivatives
Weighted Average Interest Rate Paid	0.87%

Derivatives - Narrative (Detail

Derivatives - Narrative (Details) MMBTU in Millions	6 Months Ended
	Jun. 30, 2019USD ($)MMBTU	Dec. 31, 2018USD ($)
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	25
Cash flow hedge gain (loss) to be reclassified within twelve months	$ (18,000,000)
Collateral already posted, aggregate fair value	$ 178,000,000
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
Cash flow hedge gain (loss) to be reclassified within twelve months	$ 0
GEORGIA POWER CO
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	8
Cash flow hedge gain (loss) to be reclassified within twelve months	$ 0
MISSISSIPPI POWER CO
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	4
Cash flow hedge gain (loss) to be reclassified within twelve months	$ 0
SOUTHERN POWER CO
Derivative [Line Items]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints | MMBTU	9
Cash flow hedge gain (loss) to be reclassified within twelve months	$ 0
Parent Company and Southern Power
Derivative [Line Items]
Foreign currency cash flow hedge gain (loss) to be reclassified during next 12 months	(23,000,000)
Registrants | Derivative Counterparties
Derivative [Line Items]
Collateral already posted, aggregate fair value	0
SOUTHERN Co GAS
Derivative [Line Items]
Cash flow hedge gain (loss) to be reclassified within twelve months	0
Collateral already posted, aggregate fair value	$ 178,000,000	$ 277,000,000

Derivatives - Foreign Currency

Derivatives - Foreign Currency Derivatives (Details) - 6 months ended Jun. 30, 2019 - Cash Flow Hedges of Forecasted Debt - Foreign currency derivatives € in Millions, $ in Millions	USD ($)	EUR (€)
Derivative [Line Items]
Pay Notional	$ 1,241
Receive Notional | €		€ 1,100
Fair Value Gain (Loss) at June 30, 2019	37
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) at June 30, 2019	$ 14
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) at June 30, 2019	$ 23

Derivatives - Derivative Financ

Derivatives - Derivative Financial Statement Presentation and Amounts With Balance Sheet Offsetting (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Derivatives, Fair Value [Line Items]
Derivatives, assets	$ 519	$ 837
Derivatives, liabilities	691	1,036
Derivative asset, Gross amounts offset	(328)	(524)
Derivative liability, Gross amounts offset	(506)	(801)
Derivative asset	191	313
Derivative liability	185	235
Collateral already posted, aggregate fair value	178
Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivatives, assets	442	741
Derivatives, liabilities	517	900
Derivatives not designated as hedging instruments | Gain (loss) on energy-related cash flow hedges | Other current assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	286	561
Derivatives not designated as hedging instruments | Gain (loss) on energy-related cash flow hedges | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	298	575
Derivatives not designated as hedging instruments | Gain (loss) on energy-related cash flow hedges | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	156	180
Derivatives not designated as hedging instruments | Gain (loss) on energy-related cash flow hedges | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	219	325
Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes
Derivatives, Fair Value [Line Items]
Derivatives, assets	16	17
Derivatives, liabilities	91	55
Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other current assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	7	8
Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	57	23
Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	9	9
Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	34	26
Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Assets held for sale, current
Derivatives, Fair Value [Line Items]
Derivatives, assets	0	0
Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Liabilities held for sale, current
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	0	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]
Derivatives, assets	61	79
Derivatives, liabilities	83	81
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other current assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	1	3
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	7	7
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	0	1
Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	1	2
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 assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	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 current liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	50	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 deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	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]
Derivatives, liabilities	2	30
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]
Derivatives, assets	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]
Derivatives, liabilities	23	23
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]
Derivatives, assets	60	75
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]
Derivatives, liabilities	0	0
ALABAMA POWER CO
Derivatives, Fair Value [Line Items]
Derivatives, assets	6	6
Derivatives, liabilities	18	10
Derivative asset, Gross amounts offset	(3)	(4)
Derivative liability, Gross amounts offset	(3)	(4)
Derivative asset	3	2
Derivative liability	15	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]
Derivatives, assets	6	6
Derivatives, liabilities	18	10
ALABAMA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other current assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	4	3
ALABAMA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	11	4
ALABAMA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	2	3
ALABAMA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	7	6
GEORGIA POWER CO
Derivatives, Fair Value [Line Items]
Derivatives, assets	6	6
Derivatives, liabilities	80	23
Derivative asset, Gross amounts offset	(6)	(6)
Derivative liability, Gross amounts offset	(6)	(6)
Derivative asset	0	0
Derivative liability	74	17
GEORGIA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes
Derivatives, Fair Value [Line Items]
Derivatives, assets	6	6
Derivatives, liabilities	43	21
GEORGIA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other current assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	1	2
GEORGIA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	26	8
GEORGIA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	5	4
GEORGIA POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	17	13
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]
Derivatives, assets	0	0
Derivatives, liabilities	37	2
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 assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	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 | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	37	2
MISSISSIPPI POWER CO
Derivatives, Fair Value [Line Items]
Derivatives, assets	3	3
Derivatives, liabilities	19	9
Derivative asset, Gross amounts offset	(3)	(2)
Derivative liability, Gross amounts offset	(3)	(2)
Derivative asset	0	1
Derivative liability	16	7
MISSISSIPPI POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes
Derivatives, Fair Value [Line Items]
Derivatives, assets	3	3
Derivatives, liabilities	19	9
MISSISSIPPI POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other current assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	1	1
MISSISSIPPI POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	10	3
MISSISSIPPI POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	2	2
MISSISSIPPI POWER CO | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	9	6
SOUTHERN POWER CO
Derivatives, Fair Value [Line Items]
Derivatives, assets	62	79
Derivatives, liabilities	27	31
Derivative asset, Gross amounts offset	(1)	(3)
Derivative liability, Gross amounts offset	(1)	(3)
Derivative asset	61	76
Derivative liability	26	28
SOUTHERN POWER CO | Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivatives, assets	1	0
Derivatives, liabilities	0	0
SOUTHERN POWER CO | Derivatives not designated as hedging instruments | Gain (loss) on energy-related cash flow hedges | Other current assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	1	0
SOUTHERN POWER CO | Derivatives not designated as hedging instruments | Gain (loss) on energy-related cash flow hedges | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	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]
Derivatives, assets	61	79
Derivatives, liabilities	27	31
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other current assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	1	3
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other current liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	3	6
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	0	1
SOUTHERN POWER CO | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	1	2
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]
Derivatives, assets	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]
Derivatives, liabilities	23	23
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]
Derivatives, assets	60	75
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]
Derivatives, liabilities	0	0
SOUTHERN Co GAS
Derivatives, Fair Value [Line Items]
Derivatives, assets	442	741
Derivatives, liabilities	532	909
Derivative asset, Gross amounts offset	(315)	(508)
Derivative liability, Gross amounts offset	(493)	(785)
Derivative asset	127	233
Derivative liability	39	124
Collateral already posted, aggregate fair value	178	277
Weather derivative premium		8
SOUTHERN Co GAS | Gain (loss) on energy-related cash flow hedges
Derivatives, Fair Value [Line Items]
Collateral already posted, aggregate fair value	12
SOUTHERN Co GAS | Derivatives not designated as hedging instruments
Derivatives, Fair Value [Line Items]
Derivatives, assets	441	739
Derivatives, liabilities	517	899
SOUTHERN Co GAS | Derivatives not designated as hedging instruments | Gain (loss) on energy-related cash flow hedges | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	156	180
SOUTHERN Co GAS | Derivatives not designated as hedging instruments | Gain (loss) on energy-related cash flow hedges | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	219	325
SOUTHERN Co GAS | Derivatives not designated as hedging instruments | Gain (loss) on energy-related cash flow hedges | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivatives, assets	285	559
SOUTHERN Co GAS | Derivatives not designated as hedging instruments | Gain (loss) on energy-related cash flow hedges | Liabilities from risk management activities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	298	574
SOUTHERN Co GAS | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes
Derivatives, Fair Value [Line Items]
Derivatives, assets	1	2
Derivatives, liabilities	11	9
SOUTHERN Co GAS | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred charges and assets
Derivatives, Fair Value [Line Items]
Derivatives, assets	0	0
SOUTHERN Co GAS | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Other deferred credits and liabilities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	1	1
SOUTHERN Co GAS | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivatives, assets	1	2
SOUTHERN Co GAS | Derivatives designated as hedging instruments for regulatory purposes | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Liabilities from risk management activities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	10	8
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]
Derivatives, assets	0	0
Derivatives, liabilities	4	1
SOUTHERN Co GAS | Derivatives designated as hedging instruments in cash flow and fair value hedges | Derivatives designated as hedging instruments for regulatory purposes | Gain (loss) on energy-related cash flow hedges | Assets from risk management activities
Derivatives, Fair Value [Line Items]
Derivatives, assets	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 | Gain (loss) on energy-related cash flow hedges | Liabilities from risk management activities
Derivatives, Fair Value [Line Items]
Derivatives, liabilities	$ 4	$ 1

Derivatives - Pre-tax Effects o

Derivatives - Pre-tax Effects of Derivatives Designated as Cash Flow Hedging Instruments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Collateral already posted, aggregate fair value	$ 178		$ 178
Gain (Loss) Recognized in OCI on Derivative	(44)	$ (73)	(82)	$ (11)
GEORGIA POWER CO
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	(37)	0	(37)	0
SOUTHERN POWER CO
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	(3)	(74)	(41)	(11)
SOUTHERN Co GAS
Derivative Instruments, Gain (Loss) [Line Items]
Collateral already posted, aggregate fair value	178		178		$ 277
Energy-related derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(65)		(65)		(40)
Gain (Loss) Recognized in OCI on Derivative	(6)	0	(6)	12
Energy-related derivatives | Other regulatory assets, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(48)		(48)		(19)
Energy-related derivatives | Other regulatory assets, deferred
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(23)		(23)		(16)
Energy-related derivatives | Assets held for sale, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)					(6)
Energy-related derivatives | Other regulatory liabilities, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	6		6		1
Energy-related derivatives | ALABAMA POWER CO
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(13)		(13)		(6)
Energy-related derivatives | ALABAMA POWER CO | Other regulatory assets, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(11)		(11)		(3)
Energy-related derivatives | ALABAMA POWER CO | Other regulatory assets, deferred
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(5)		(5)		(3)
Energy-related derivatives | ALABAMA POWER CO | Assets held for sale, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)					0
Energy-related derivatives | ALABAMA POWER CO | Other regulatory liabilities, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	3		3		0
Energy-related derivatives | GEORGIA POWER CO
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(37)		(37)		(15)
Energy-related derivatives | GEORGIA POWER CO | Other regulatory assets, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(25)		(25)		(6)
Energy-related derivatives | GEORGIA POWER CO | Other regulatory assets, deferred
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(12)		(12)		(9)
Energy-related derivatives | GEORGIA POWER CO | Assets held for sale, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)					0
Energy-related derivatives | GEORGIA POWER CO | Other regulatory liabilities, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	0		0		0
Energy-related derivatives | MISSISSIPPI POWER CO
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(16)		(16)		(6)
Energy-related derivatives | MISSISSIPPI POWER CO | Other regulatory assets, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(10)		(10)		(2)
Energy-related derivatives | MISSISSIPPI POWER CO | Other regulatory assets, deferred
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(6)		(6)		(4)
Energy-related derivatives | MISSISSIPPI POWER CO | Assets held for sale, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)					0
Energy-related derivatives | MISSISSIPPI POWER CO | Other regulatory liabilities, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	0		0		0
Energy-related derivatives | SOUTHERN POWER CO
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	(2)	(1)	(2)	10
Energy-related derivatives | SOUTHERN Co GAS
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	1		1		(7)
Collateral already posted, aggregate fair value	12		12
Energy-related derivatives | SOUTHERN Co GAS | Other regulatory assets, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	(2)		(2)		(8)
Energy-related derivatives | SOUTHERN Co GAS | Other regulatory assets, deferred
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	0		0		0
Energy-related derivatives | SOUTHERN Co GAS | Assets held for sale, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)					0
Energy-related derivatives | SOUTHERN Co GAS | Other regulatory liabilities, current
Derivative Instruments, Gain (Loss) [Line Items]
Total energy-related derivative gains (losses)	3		3		$ 1
Interest rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	(37)	0	(37)	(2)
Foreign currency derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	(1)	(73)	(39)	(21)
Foreign currency derivatives | SOUTHERN POWER CO
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	(1)	(73)	(39)	(21)
Total interest expense, net of amounts capitalized | Interest rate derivatives | GEORGIA POWER CO
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) Recognized in OCI on Derivative	$ (37)	$ 0	$ (37)	$ 0

Derivatives - Location and Amou

Derivatives - Location and Amount of Gain (Loss) Recognized in Income on Cash Flow and Fair Value Hedging Relationships (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative [Line Items]
Depreciation and amortization	$ 755	$ 783	$ 1,506	$ 1,552
Total interest expense, net of amounts capitalized	(429)	(470)	(859)	(928)
Total other income (expense), net	99	78	176	138
Cash Flow Hedging | Gain (loss) on energy-related cash flow hedges | Total depreciation and amortization
Derivative [Line Items]
Gain (loss) on hedge	(1)	1	(4)	2
Cash Flow Hedging | Interest rate derivatives | Total interest expense, net of amounts capitalized
Derivative [Line Items]
Gain (loss) on hedge	(5)	(6)	(9)	(11)
Cash Flow Hedging | Foreign currency derivatives | Total interest expense, net of amounts capitalized
Derivative [Line Items]
Gain (loss) on hedge	(6)	(7)	(12)	(12)
Cash Flow Hedging | Foreign currency derivatives | Total other income (expense), net
Derivative [Line Items]
Gain (loss) on hedge	16	(73)	(8)	(37)
Fair Value Hedging | Interest rate derivatives | Total interest expense, net of amounts capitalized
Derivative [Line Items]
Gain (loss) on hedge	19	(7)	33	(31)
SOUTHERN POWER CO
Derivative [Line Items]
Depreciation and amortization	119	125	237	240
Total interest expense, net of amounts capitalized	(41)	(46)	(84)	(93)
Total other income (expense), net	40	2	41	5
SOUTHERN POWER CO | Cash Flow Hedging | Gain (loss) on energy-related cash flow hedges | Total depreciation and amortization
Derivative [Line Items]
Gain (loss) on hedge	(1)	1	(4)	2
SOUTHERN POWER CO | Cash Flow Hedging | Foreign currency derivatives | Total interest expense, net of amounts capitalized
Derivative [Line Items]
Gain (loss) on hedge	(6)	(7)	(12)	(12)
SOUTHERN POWER CO | Cash Flow Hedging | Foreign currency derivatives | Total other income (expense), net
Derivative [Line Items]
Gain (loss) on hedge	$ 16	$ (73)	$ (8)	$ (37)

Derivatives - Cumulative Basis

Derivatives - Cumulative Basis Adjustments for Fair Value Hedges (Details) - Fair Value Hedging - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Securities due within one year
Derivative [Line Items]
Carrying Amount of the Hedged Item	$ (499)	$ (498)
Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item	1	2
Securities due within one year | GEORGIA POWER CO
Derivative [Line Items]
Carrying Amount of the Hedged Item	(499)	(498)
Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item	1	2
Long-term debt
Derivative [Line Items]
Carrying Amount of the Hedged Item	(2,087)	(2,052)
Cumulative Amount of Fair Value Hedging Adjustment included in Carrying Amount of the Hedged Item	$ 7	$ 41

Derivatives - Pre-tax Effects_2

Derivatives - Pre-tax Effects of Derivatives Not Designated as Hedging (Details) - Derivatives not designated as hedging instruments - Energy-related derivatives - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	$ 45	$ (26)	$ 86	$ (39)
Natural gas revenues
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	50	(28)	83	(43)
Cost of natural gas
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	(5)	2	3	4
SOUTHERN Co GAS
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	45	(26)	86	(39)
SOUTHERN Co GAS | Natural gas revenues
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	50	(28)	83	(43)
SOUTHERN Co GAS | Cost of natural gas
Derivative Instruments, Gain (Loss) [Line Items]
Derivative instruments not designated as hedging instruments, gain (loss), net	$ (5)	$ 2	$ 3	$ 4

Acquisitions and Dispositions -

Acquisitions and Dispositions - Southern Company Narrative (Details) - USD ($) $ in Millions	Jan. 01, 2019	Jun. 30, 2019	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2019	Jul. 22, 2019
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Preliminary gain			$ 2,512	$ (35)
Goodwill impairment		$ 32	$ 32
Disposal Group, Disposed of by Sale, Not Discontinued Operations | GULF POWER CO
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Proceeds from divestiture of businesses, net of cash divested	$ 5,800
Amount of indebtedness assumed at closing	$ 1,300
Disposal Group, Held-for-sale, Not Discontinued Operations | PowerSecure Utility Infrastructure Services Unit
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill impairment		$ 32
Scenario, Forecast | Disposal Group, Disposed of by Sale, Not Discontinued Operations | GULF POWER CO
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Preliminary gain					$ 2,500
Preliminary gain, net of tax					$ 1,300
Subsequent Event | Disposal Group, Disposed of by Sale, Not Discontinued Operations | PowerSecure Utility Infrastructure Services Unit
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Sale price						$ 71

Acquisitions and Dispositions_2

Acquisitions and Dispositions - Southern Power Narrative (Details) $ in Millions	Oct. 01, 2019USD ($)	Jun. 13, 2019USD ($)MW	Jun. 30, 2019USD ($)MW	Jun. 30, 2019USD ($)MW	Dec. 31, 2019USD ($)	May 31, 2019MW	May 04, 2019MW	Dec. 31, 2018USD ($)
Business Acquisition [Line Items]
Construction work in progress			$ 7,568	$ 7,568				$ 7,254
Property, plant, and equipment, subject to lien			114,867	114,867				116,914
SOUTHERN POWER CO
Business Acquisition [Line Items]
Construction work in progress			419	419				430
Property, plant, and equipment, subject to lien			14,518	14,518				$ 14,883
SOUTHERN POWER CO | Lien
Business Acquisition [Line Items]
Property, plant, and equipment, subject to lien			545	545
SOUTHERN POWER CO | Disposal Group, Held-for-sale, Not Discontinued Operations | Mankato expansion | Scenario, Forecast
Business Acquisition [Line Items]
Gain on termination fee	$ 15
SOUTHERN POWER CO | Disposal Group, Held-for-sale, Not Discontinued Operations | Nacogdoches Biomass-Fueled Facility
Business Acquisition [Line Items]
Approximate nameplate capacity (MW) | MW		115
Nacogdoches biomass-fueled facility		$ 461
After tax gain		$ 88
SOUTHERN POWER CO | Wind Generating Facility
Business Acquisition [Line Items]
Gain on sale				14
SOUTHERN POWER CO | Series of Construction Projects
Business Acquisition [Line Items]
Construction work in progress			186	186
SOUTHERN POWER CO | Series of Construction Projects | Minimum
Business Acquisition [Line Items]
Estimated future construction payments			405	405
SOUTHERN POWER CO | Series of Construction Projects | Maximum
Business Acquisition [Line Items]
Estimated future construction payments			450	$ 450
SOUTHERN POWER CO | Diamond State Generation Partners
Business Acquisition [Line Items]
Contributions to acquire majority interest			$ 116
SOUTHERN POWER CO | Diamond State Generation Partners | Scenario, Forecast
Business Acquisition [Line Items]
Contributions to acquire majority interest					$ 173
SOUTHERN POWER CO | Mankato expansion
Business Acquisition [Line Items]
Approximate nameplate capacity (MW) | MW			385	385		385	385

Acquisitions and Dispositions_3

Acquisitions and Dispositions - Schedule of Construction Projects (Details) - SOUTHERN POWER CO - MW	1 Months Ended	3 Months Ended
	May 31, 2019	Jun. 30, 2020	Dec. 31, 2019	Jun. 30, 2019	May 04, 2019	Aug. 31, 2018	May 31, 2018
Mankato expansion
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)	385			385	385
PPA Contract Period	20 years
Wild Horse Mountain | Wild Horse Mountain
Business Acquisition [Line Items]
Ownership percentage by parent							100.00%
Reading | Reading
Business Acquisition [Line Items]
Ownership percentage by parent						100.00%
Reading | Reading | Class B Membership Interest
Business Acquisition [Line Items]
Ownership percentage by parent						100.00%
Scenario, Forecast | Wild Horse Mountain
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)			100
PPA Contract Period			20 years
Scenario, Forecast | Reading
Business Acquisition [Line Items]
Approximate Nameplate Capacity (MW)		200
PPA Contract Period		12 years

Acquisitions and Dispositions_4

Acquisitions and Dispositions - Assets Held for Sale (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Assets Held for Sale:
Current assets	$ 58	$ 393
Liabilities Held for Sale:
Current liabilities	36	425
Other non-current liabilities	39	2,836
SOUTHERN POWER CO
Liabilities Held for Sale:
Current liabilities	10	15
Disposal Group, Held-for-sale, Not Discontinued Operations
Assets Held for Sale:
Current assets	58	393
Total property, plant, and equipment	588	4,583
Goodwill and other intangible assets	51	40
Other non-current assets	46	727
Total Assets Held for Sale	743	5,743
Liabilities Held for Sale:
Current liabilities	36	425
Other non-current liabilities	39	932
Long-term debt		1,286
Accumulated deferred income taxes		618
Total Liabilities Held for Sale	75	3,261
Disposal Group, Held-for-sale, Not Discontinued Operations | SOUTHERN POWER CO
Assets Held for Sale:
Current assets	10	8
Total property, plant, and equipment	559	536
Goodwill and other intangible assets	40	40
Other non-current assets	0	0
Total Assets Held for Sale	609	584
Liabilities Held for Sale:
Current liabilities	10	15
Other non-current liabilities	0	0
Long-term debt		0
Accumulated deferred income taxes		0
Total Liabilities Held for Sale	$ 10	$ 15

Acquisitions and Dispositions_5

Acquisitions and Dispositions - Pre-tax Profit (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
GULF POWER CO
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Earnings before income taxes	$ 0	$ 31	$ 0	$ 87
SOUTHERN POWER CO | Florida Plants
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Earnings before income taxes	0	14	0	24
SOUTHERN POWER CO | Plant Nacogdoches
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Earnings before income taxes	$ 9	$ 7	$ 16	$ 13

Leases - Major Categories of Le

Leases - Major Categories of Lease Obligations (Details) $ in Millions	Jun. 30, 2019USD ($)
Lessee, Lease, Description [Line Items]
Lease obligations	$ 2,218
Electric generating units
Lessee, Lease, Description [Line Items]
Lease obligations	1,072
Real estate/land
Lessee, Lease, Description [Line Items]
Lease obligations	800
Communication towers
Lessee, Lease, Description [Line Items]
Lease obligations	147
Railcars
Lessee, Lease, Description [Line Items]
Lease obligations	54
Other
Lessee, Lease, Description [Line Items]
Lease obligations	145
ALABAMA POWER CO
Lessee, Lease, Description [Line Items]
Lease obligations	190
ALABAMA POWER CO | Electric generating units
Lessee, Lease, Description [Line Items]
Lease obligations	150
ALABAMA POWER CO | Real estate/land
Lessee, Lease, Description [Line Items]
Lease obligations	4
ALABAMA POWER CO | Communication towers
Lessee, Lease, Description [Line Items]
Lease obligations	1
ALABAMA POWER CO | Railcars
Lessee, Lease, Description [Line Items]
Lease obligations	25
ALABAMA POWER CO | Other
Lessee, Lease, Description [Line Items]
Lease obligations	10
GEORGIA POWER CO
Lessee, Lease, Description [Line Items]
Lease obligations	1,686
GEORGIA POWER CO | Electric generating units
Lessee, Lease, Description [Line Items]
Lease obligations	1,580
GEORGIA POWER CO | Real estate/land
Lessee, Lease, Description [Line Items]
Lease obligations	62
GEORGIA POWER CO | Communication towers
Lessee, Lease, Description [Line Items]
Lease obligations	3
GEORGIA POWER CO | Railcars
Lessee, Lease, Description [Line Items]
Lease obligations	27
GEORGIA POWER CO | Other
Lessee, Lease, Description [Line Items]
Lease obligations	14
MISSISSIPPI POWER CO
Lessee, Lease, Description [Line Items]
Lease obligations	7
MISSISSIPPI POWER CO | Electric generating units
Lessee, Lease, Description [Line Items]
Lease obligations	0
MISSISSIPPI POWER CO | Real estate/land
Lessee, Lease, Description [Line Items]
Lease obligations	2
MISSISSIPPI POWER CO | Communication towers
Lessee, Lease, Description [Line Items]
Lease obligations	0
MISSISSIPPI POWER CO | Railcars
Lessee, Lease, Description [Line Items]
Lease obligations	3
MISSISSIPPI POWER CO | Other
Lessee, Lease, Description [Line Items]
Lease obligations	2
SOUTHERN POWER CO
Lessee, Lease, Description [Line Items]
Lease obligations	395
SOUTHERN POWER CO | Electric generating units
Lessee, Lease, Description [Line Items]
Lease obligations	0
SOUTHERN POWER CO | Real estate/land
Lessee, Lease, Description [Line Items]
Lease obligations	395
SOUTHERN POWER CO | Communication towers
Lessee, Lease, Description [Line Items]
Lease obligations	0
SOUTHERN POWER CO | Railcars
Lessee, Lease, Description [Line Items]
Lease obligations	0
SOUTHERN POWER CO | Other
Lessee, Lease, Description [Line Items]
Lease obligations	0
SOUTHERN Co GAS
Lessee, Lease, Description [Line Items]
Lease obligations	94
SOUTHERN Co GAS | Electric generating units
Lessee, Lease, Description [Line Items]
Lease obligations	0
SOUTHERN Co GAS | Real estate/land
Lessee, Lease, Description [Line Items]
Lease obligations	81
SOUTHERN Co GAS | Communication towers
Lessee, Lease, Description [Line Items]
Lease obligations	13
SOUTHERN Co GAS | Railcars
Lessee, Lease, Description [Line Items]
Lease obligations	0
SOUTHERN Co GAS | Other
Lessee, Lease, Description [Line Items]
Lease obligations	$ 0

Leases - Narrative (Details)

Leases - Narrative (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Lessee, Lease, Description [Line Items]
Remaining terms	14 years
Total estimate obligations of leases that have not yet commenced	$ 81
Maximum
Lessee, Lease, Description [Line Items]
Lease term, lease not yet commenced	31 years
Real estate | Maximum
Lessee, Lease, Description [Line Items]
Remaining terms	25 years
Communication towers | Maximum
Lessee, Lease, Description [Line Items]
Lessee, lease term	10 years
Lessee, renewal period	20 years
Fuel cells | Maximum
Lessee, Lease, Description [Line Items]
Lessor, lease term, operating lease	15 years
GEORGIA POWER CO
Lessee, Lease, Description [Line Items]
Remaining terms	10 years 6 months
Lease obligations	$ 1,517
GEORGIA POWER CO | Real estate | Maximum
Lessee, Lease, Description [Line Items]
Remaining terms	25 years
GEORGIA POWER CO | Electric generating units | Affiliate
Lessee, Lease, Description [Line Items]
Lease obligations	$ 660
GEORGIA POWER CO | Electric generating units | Minimum
Lessee, Lease, Description [Line Items]
Remaining terms	4 years
GEORGIA POWER CO | Electric generating units | Maximum
Lessee, Lease, Description [Line Items]
Remaining terms	18 years
GEORGIA POWER CO | Outdoor lighting | Maximum
Lessee, Lease, Description [Line Items]
Lessor, lease term, operating lease	5 years
SOUTHERN Co GAS
Lessee, Lease, Description [Line Items]
Remaining terms	9 years 8 months 12 days
Lease obligations	$ 94
SOUTHERN Co GAS | Maximum
Lessee, Lease, Description [Line Items]
Lessor, remaining term	24 years
SOUTHERN Co GAS | Real estate | Maximum
Lessee, Lease, Description [Line Items]
Remaining terms	25 years
SOUTHERN POWER CO
Lessee, Lease, Description [Line Items]
Remaining terms	33 years 6 months
Lease obligations	$ 395
Total estimate obligations of leases that have not yet commenced	$ 81
SOUTHERN POWER CO | Maximum
Lessee, Lease, Description [Line Items]
Lease term, lease not yet commenced	31 years
SOUTHERN POWER CO | Land | Maximum
Lessee, Lease, Description [Line Items]
Lessee, lease term	48 years
SOUTHERN POWER CO | Electric generating units | Maximum
Lessee, Lease, Description [Line Items]
Lessor, lease term, operating lease	28 years
ALABAMA POWER CO
Lessee, Lease, Description [Line Items]
Remaining terms	3 years 7 months 6 days
Lease obligations	$ 185
ALABAMA POWER CO | Electric generating units | Minimum
Lessee, Lease, Description [Line Items]
Remaining terms	4 years
ALABAMA POWER CO | Electric generating units | Maximum
Lessee, Lease, Description [Line Items]
Remaining terms	18 years
ALABAMA POWER CO | Outdoor lighting | Maximum
Lessee, Lease, Description [Line Items]
Lessor, lease term, operating lease	5 years
MISSISSIPPI POWER CO
Lessee, Lease, Description [Line Items]
Remaining terms	7 years
Lease obligations	$ 7
MISSISSIPPI POWER CO | Electric generating units | Maximum
Lessee, Lease, Description [Line Items]
Lessor, lease term, sales-type lease	20 years
MISSISSIPPI POWER CO | Outdoor lighting | Maximum
Lessee, Lease, Description [Line Items]
Lessor, lease term, operating lease	5 years

Leases - Balance Sheet Amounts

Leases - Balance Sheet Amounts Recorded for Operating and Financing Leases (Details) $ in Millions	Jun. 30, 2019USD ($)
Operating Leases
Operating lease ROU assets, net, including held for sale	$ 1,907
Operating lease ROU assets, net	1,862
Operating lease obligations - current, including held for sale	241
Operating lease obligations - current	228
Operating lease obligations - non current, including held for sale	1,733
Operating lease obligations - non current	1,702
Total operating lease obligations, including held for sale	1,974
Finance Leases
Finance lease ROU assets, net	237
Finance lease obligations - current	24
Finance lease obligations - noncurrent	220
Total finance lease obligations	244
ALABAMA POWER CO
Operating Leases
Operating lease ROU assets, net	152
Operating lease obligations - current	48
Operating lease obligations - non current	137
Total operating lease obligations	185
Finance Leases
Finance lease ROU assets, net	5
Finance lease obligations - current	1
Finance lease obligations - noncurrent	4
Total finance lease obligations	5
GEORGIA POWER CO
Operating Leases
Operating lease ROU assets, net	1,492
Operating lease obligations - current	140
Operating lease obligations - non current	1,377
Total operating lease obligations	1,517
Finance Leases
Finance lease ROU assets, net	142
Finance lease obligations - current	10
Finance lease obligations - noncurrent	159
Total finance lease obligations	169
MISSISSIPPI POWER CO
Operating Leases
Operating lease ROU assets, net	7
Operating lease obligations - current	2
Operating lease obligations - non current	5
Total operating lease obligations	7
Finance Leases
Finance lease ROU assets, net	0
Finance lease obligations - current	0
Finance lease obligations - noncurrent	0
Total finance lease obligations	0
SOUTHERN POWER CO
Operating Leases
Operating lease ROU assets, net	370
Operating lease obligations - current	22
Operating lease obligations - non current	373
Total operating lease obligations	395
Finance Leases
Finance lease ROU assets, net	0
Finance lease obligations - current	0
Finance lease obligations - noncurrent	0
Total finance lease obligations	0
SOUTHERN Co GAS
Operating Leases
Operating lease ROU assets, net	95
Operating lease obligations - current	15
Operating lease obligations - non current	79
Total operating lease obligations	94
Finance Leases
Finance lease ROU assets, net	0
Finance lease obligations - current	0
Finance lease obligations - noncurrent	0
Total finance lease obligations	$ 0

Leases - Lease Costs (Details)

Leases - Lease Costs (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Lease cost
Operating lease cost	$ 77	$ 147
Finance lease cost:
Amortization of ROU assets	7	14
Interest on lease obligations	3	6
Total finance lease cost	10	20
Short-term lease costs	13	30
Variable lease cost	29	48
Sublease income	0	0
Total lease cost	129	245
ALABAMA POWER CO
Lease cost
Operating lease cost	13	20
Finance lease cost:
Amortization of ROU assets	0	0
Interest on lease obligations	0	0
Total finance lease cost	0	0
Short-term lease costs	6	11
Variable lease cost	1	1
Sublease income	0	0
Total lease cost	20	32
GEORGIA POWER CO
Lease cost
Operating lease cost	50	99
Finance lease cost:
Amortization of ROU assets	4	7
Interest on lease obligations	4	9
Total finance lease cost	8	16
Short-term lease costs	6	12
Variable lease cost	25	41
Sublease income	0	0
Total lease cost	89	168
MISSISSIPPI POWER CO
Lease cost
Operating lease cost	1	1
Finance lease cost:
Amortization of ROU assets	0	0
Interest on lease obligations	0	0
Total finance lease cost	0	0
Short-term lease costs	0	0
Variable lease cost	0	0
Sublease income	0	0
Total lease cost	1	1
SOUTHERN POWER CO
Lease cost
Operating lease cost	7	14
Finance lease cost:
Amortization of ROU assets	0	0
Interest on lease obligations	0	0
Total finance lease cost	0	0
Short-term lease costs	0	0
Variable lease cost	1	3
Sublease income	0	0
Total lease cost	8	17
SOUTHERN Co GAS
Lease cost
Operating lease cost	5	9
Finance lease cost:
Amortization of ROU assets	0	0
Interest on lease obligations	0	0
Total finance lease cost	0	0
Short-term lease costs	0	0
Variable lease cost	0	0
Sublease income	0	0
Total lease cost	$ 5	$ 9

Leases - Other Information (Det

Leases - Other Information (Details) $ in Millions	6 Months Ended
	Jun. 30, 2019USD ($)
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 129
Operating cash flows from finance leases	2
Financing cash flows from finance leases	16
ROU assets obtained in exchange for new operating lease obligations	55
ROU assets obtained in exchange for new finance lease obligations	$ 33
Weighted-average remaining lease term in years:
Operating leases	14 years
Finance leases	18 years 3 months 18 days
Weighted-average discount rate:
Operating leases	4.53%
Finance leases	5.05%
ALABAMA POWER CO
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 20
Operating cash flows from finance leases	0
Financing cash flows from finance leases	0
ROU assets obtained in exchange for new operating lease obligations	5
ROU assets obtained in exchange for new finance lease obligations	$ 1
Weighted-average remaining lease term in years:
Operating leases	3 years 7 months 6 days
Finance leases	12 years 9 months 18 days
Weighted-average discount rate:
Operating leases	3.33%
Finance leases	3.67%
GEORGIA POWER CO
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 75
Operating cash flows from finance leases	10
Financing cash flows from finance leases	3
ROU assets obtained in exchange for new operating lease obligations	13
ROU assets obtained in exchange for new finance lease obligations	$ 28
Weighted-average remaining lease term in years:
Operating leases	10 years 6 months
Finance leases	11 years
Weighted-average discount rate:
Operating leases	4.46%
Finance leases	10.69%
MISSISSIPPI POWER CO
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 1
Operating cash flows from finance leases	0
Financing cash flows from finance leases	0
ROU assets obtained in exchange for new operating lease obligations	0
ROU assets obtained in exchange for new finance lease obligations	$ 0
Weighted-average remaining lease term in years:
Operating leases	7 years
Weighted-average discount rate:
Operating leases	4.06%
SOUTHERN POWER CO
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 12
Operating cash flows from finance leases	0
Financing cash flows from finance leases	0
ROU assets obtained in exchange for new operating lease obligations	0
ROU assets obtained in exchange for new finance lease obligations	$ 0
Weighted-average remaining lease term in years:
Operating leases	33 years 6 months
Weighted-average discount rate:
Operating leases	5.68%
SOUTHERN Co GAS
Cash paid for amounts included in the measurements of lease obligations:
Operating cash flows from operating leases	$ 9
Operating cash flows from finance leases	0
Financing cash flows from finance leases	0
ROU assets obtained in exchange for new operating lease obligations	13
ROU assets obtained in exchange for new finance lease obligations	$ 0
Weighted-average remaining lease term in years:
Operating leases	9 years 8 months 12 days
Weighted-average discount rate:
Operating leases	3.73%

Leases - Maturities of Lease Li

Leases - Maturities of Lease Liabilities (Details) $ in Millions	Jun. 30, 2019USD ($)
Operating leases:
2019 (remaining)	$ 178
2020	295
2021	279
2022	268
2023	204
Thereafter	1,661
Total	2,885
Less: Present value discount	911
Operating lease obligations, including held for sale	1,974
Finance leases:
2019 (remaining)	16
2020	33
2021	27
2022	23
2023	18
Thereafter	266
Total	383
Less: Present value discount	139
Finance lease obligations	244
ALABAMA POWER CO
Operating leases:
2019 (remaining)	33
2020	53
2021	52
2022	52
2023	4
Thereafter	2
Total	196
Less: Present value discount	11
Operating lease obligations	185
Finance leases:
2019 (remaining)	0
2020	1
2021	1
2022	1
2023	1
Thereafter	1
Total	5
Less: Present value discount	0
Finance lease obligations	5
GEORGIA POWER CO
Operating leases:
2019 (remaining)	129
2020	203
2021	198
2022	196
2023	197
Thereafter	990
Total	1,913
Less: Present value discount	396
Operating lease obligations	1,517
Finance leases:
2019 (remaining)	16
2020	28
2021	25
2022	25
2023	25
Thereafter	165
Total	284
Less: Present value discount	115
Finance lease obligations	169
MISSISSIPPI POWER CO
Operating leases:
2019 (remaining)	1
2020	2
2021	1
2022	1
2023	1
Thereafter	2
Total	8
Less: Present value discount	1
Operating lease obligations	7
Finance leases:
2019 (remaining)	0
2020	0
2021	0
2022	0
2023	0
Thereafter	0
Total	0
Less: Present value discount	0
Finance lease obligations	0
SOUTHERN POWER CO
Operating leases:
2019 (remaining)	13
2020	22
2021	23
2022	23
2023	24
Thereafter	849
Total	954
Less: Present value discount	559
Operating lease obligations	395
Finance leases:
2019 (remaining)	0
2020	0
2021	0
2022	0
2023	0
Thereafter	0
Total	0
Less: Present value discount	0
Finance lease obligations	0
SOUTHERN Co GAS
Operating leases:
2019 (remaining)	9
2020	17
2021	16
2022	13
2023	11
Thereafter	49
Total	115
Less: Present value discount	21
Operating lease obligations	94
Finance leases:
2019 (remaining)	0
2020	0
2021	0
2022	0
2023	0
Thereafter	0
Total	0
Less: Present value discount	0
Finance lease obligations	$ 0

Leases - Lease Income (Details)

Leases - Lease Income (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2019
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	$ 2	$ 5
Lease income - operating leases	67	139
Variable lease income	115	182
Total lease income	184	326
GEORGIA POWER CO
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	0	0
Lease income - operating leases	19	39
Variable lease income	0	0
Total lease income	19	39
MISSISSIPPI POWER CO
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	2	5
Lease income - operating leases	0	0
Variable lease income	0	0
Total lease income	2	5
SOUTHERN POWER CO
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	0	0
Lease income - operating leases	39	80
Variable lease income	125	198
Total lease income	164	278
SOUTHERN Co GAS
Lessor, Lease, Description [Line Items]
Lease income - interest income on sales-type leases	0	0
Lease income - operating leases	9	17
Variable lease income	0	0
Total lease income	$ 9	$ 17

Leases - Undiscounted Cash Flow

Leases - Undiscounted Cash Flows to be Received Under Tolling Arrangements Accounted for as Sales-type Leases (Details) $ in Millions	Jun. 30, 2019USD ($)
Lessor, Lease, Description [Line Items]
2019 (remaining)	$ 7
2020	14
2021	14
2022	13
2023	12
Thereafter	135
Total undiscounted cash flows	195
Lease receivable	106
Difference between undiscounted cash flows and discounted cash flows	89
MISSISSIPPI POWER CO
Lessor, Lease, Description [Line Items]
2019 (remaining)	7
2020	14
2021	14
2022	13
2023	12
Thereafter	135
Total undiscounted cash flows	195
Lease receivable	106
Difference between undiscounted cash flows and discounted cash flows	$ 89

Leases - Undiscounted Cash Fl_2

Leases - Undiscounted Cash Flows to be Received Under PPAs Accounted for as Operating Leases (Details) $ in Millions	Jun. 30, 2019USD ($)
Lessor, Lease, Description [Line Items]
2019 (remaining)	$ 75
2020	125
2021	118
2022	109
2023	103
Thereafter	1,142
Total	1,672
GEORGIA POWER CO
Lessor, Lease, Description [Line Items]
2019 (remaining)	13
2020	26
2021	18
2022	8
2023	2
Thereafter	0
Total	67
SOUTHERN POWER CO
Lessor, Lease, Description [Line Items]
2019 (remaining)	52
2020	65
2021	66
2022	68
2023	69
Thereafter	350
Total	670
SOUTHERN Co GAS
Lessor, Lease, Description [Line Items]
2019 (remaining)	17
2020	35
2021	35
2022	34
2023	34
Thereafter	497
Total	$ 652

Segment and Related Informati_3

Segment and Related Information - Narrative (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019USD ($)state	Jun. 30, 2018USD ($)	Jun. 30, 2019USD ($)statepipelinesegment	Jun. 30, 2018USD ($)
Segment Reporting Information [Line Items]
Number of states in which entity operates | state	3		3
Total operating revenues	$ 5,098	$ 5,627	$ 10,510	$ 11,999
Natural gas
Segment Reporting Information [Line Items]
Total operating revenues	689	706	2,163	2,314
SOUTHERN POWER CO
Segment Reporting Information [Line Items]
Total operating revenues	510	555	953	1,064
SOUTHERN POWER CO | Wholesale revenues, affiliates
Segment Reporting Information [Line Items]
Total operating revenues	117	109	204	192
SOUTHERN POWER CO | Traditional Electric Operating Companies | Wholesale revenues, affiliates
Segment Reporting Information [Line Items]
Total operating revenues	$ 117	109	$ 204	192
SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Number of states in which entity operates | state	4		4
Total operating revenues	$ 689	730	$ 2,163	2,369
Number of reportable segments | segment			4
SOUTHERN Co GAS | Pipeline
Segment Reporting Information [Line Items]
Number of pipeline construction projects | pipeline			2
SOUTHERN Co GAS | SNG
Segment Reporting Information [Line Items]
Ownership percentage, equity method investment	50.00%		50.00%
SOUTHERN Co GAS | Dalton Pipeline
Segment Reporting Information [Line Items]
Ownership percentage, equity method investment	50.00%		50.00%
SOUTHERN Co GAS | Natural gas
Segment Reporting Information [Line Items]
Total operating revenues	$ 688	710	$ 2,163	2,341
SOUTHERN Co GAS | Traditional Electric Operating Companies | Natural gas
Segment Reporting Information [Line Items]
Total operating revenues	0	0	0	0
SOUTHERN Co GAS | SOUTHERN POWER CO | Natural gas
Segment Reporting Information [Line Items]
Total operating revenues	$ 16	$ 22	$ 33	$ 58

Segment and Related Informati_4

Segment and Related Information - Financial Data for Business Segments (Details) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019USD ($)	Mar. 31, 2019USD ($)	Jun. 30, 2018USD ($)utility	Mar. 31, 2018USD ($)	Jun. 30, 2019USD ($)	Jun. 30, 2018USD ($)utility	Dec. 31, 2018USD ($)
Segment Reporting Information [Line Items]
Operating revenues	$ 5,098		$ 5,627		$ 10,510	$ 11,999
Segment net income (loss)	899	$ 2,084	(154)	$ 938	2,982	784
Goodwill	5,282				5,282		$ 5,315
Total assets	114,867				114,867		116,914
Goodwill impairment	32				32
Asset impairment					32	161
Loss on disposition	(8)		36		(2,506)	36
SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	689		730		2,163	2,369
Segment net income (loss)	106	270	(31)	279	376	248
Goodwill	5,015				5,015		5,015
Total assets	20,761				20,761		21,448
Goodwill impairment	0		0		0	42
Loss on disposition	0		$ 36		0	$ 36
SOUTHERN Co GAS | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Segment Reporting Information [Line Items]
Number of natural gas distribution utilities disposed | utility			3			3
SOUTHERN POWER CO
Segment Reporting Information [Line Items]
Operating revenues	510		$ 555		953	$ 1,064
Segment net income (loss)	174	$ 56	22	$ 121	230	143
Total assets	14,518				14,518		14,883
Asset impairment	0		119		0	119
Impairment charge, net of tax			89			89
Loss on disposition	(23)		0		(23)	0
SOUTHERN POWER CO | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Plant Nacogdoches
Segment Reporting Information [Line Items]
Pre-tax gain on the sale of Plant Nacogdoches	23				23
Gain on the sale of Plant Nacogdoches, after tax	88				88
Electric Utilities
Segment Reporting Information [Line Items]
Operating revenues	4,290		4,565		8,085	8,948
Segment net income (loss)	956		(26)		1,576	706
Goodwill	2				2		2
Total assets	92,049				92,049		93,959
Traditional Electric Operating Companies | GEORGIA POWER AND MISSISSIPPI POWER CO | Kemper County Energy Facility
Segment Reporting Information [Line Items]
Public utilities, property, plant and equipment, amount of loss (recovery) on plant abandonment	4		1,100		6	1,100
Public utilities, property, plant and equipment, amount of loss (recovery) on plant abandonment after tax	3		800		5	800
SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	689		730		2,163	2,369
SOUTHERN Co GAS | Disposal Group, Disposed of by Sale, Not Discontinued Operations | Pivotal Home Solutions
Segment Reporting Information [Line Items]
Goodwill impairment						42
All Other | Disposal Group, Disposed of by Sale, Not Discontinued Operations | GULF POWER CO
Segment Reporting Information [Line Items]
Preliminary pre-tax gain (reduction)	15				2,500
Preliminary after-tax gain (reduction)	(11)				1,300
Gas Distribution Operations | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Goodwill	4,034				4,034		4,034
Gas Distribution Operations | SOUTHERN Co GAS | Disposal Group, Disposed of by Sale, Not Discontinued Operations
Segment Reporting Information [Line Items]
Operating revenues			70			237
Gas Marketing Services | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Goodwill	981				981		981
Operating revenues			24			55
Loss on disposition			36			36
Operating Segments | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	682		724		2,177	2,381
Segment net income (loss)	103		(8)		376	284
Total assets	21,360				21,360		21,918
Operating Segments | Traditional Electric Operating Companies | Electric Utilities
Segment Reporting Information [Line Items]
Operating revenues	3,899		4,124		7,343	8,104
Segment net income (loss)	782		(48)		1,346	563
Goodwill	0				0		0
Total assets	78,314				78,314		79,382
Operating Segments | SOUTHERN POWER CO | Electric Utilities
Segment Reporting Information [Line Items]
Operating revenues	510		555		953	1,064
Segment net income (loss)	174		22		230	143
Goodwill	2				2		2
Total assets	14,518				14,518		14,883
Operating Segments | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	689		730		2,163	2,369
Segment net income (loss)	106		(31)		376	248
Goodwill	5,015				5,015		5,015
Total assets	20,761				20,761		21,448
Operating Segments | All Other
Segment Reporting Information [Line Items]
Operating revenues	186		381		368	782
Segment net income (loss)	(154)		(100)		1,041	(174)
Goodwill	265				265		298
Total assets	3,343				3,343		3,285
Operating Segments | All Other | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	13		11		24	26
Segment net income (loss)	3		(23)		0	(36)
Total assets	10,934				10,934		11,112
Operating Segments | Gas Distribution Operations | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	568		643		1,740	1,856
Segment net income (loss)	58		68		191	216
Total assets	17,397				17,397		17,266
Operating Segments | Gas Pipeline Investments | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	8		8		16	16
Segment net income (loss)	25		21		57	48
Total assets	1,768				1,768		1,763
Operating Segments | Wholesale Gas Services | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	48		(16)		134	150
Segment net income (loss)	23		(21)		70	83
Total assets	668				668		1,302
Less Gross Gas Costs	1,238		1,454		3,165	3,393
Operating Segments | Wholesale Gas Services | SOUTHERN Co GAS | Third Party Gross Revenues
Segment Reporting Information [Line Items]
Operating revenues	1,223		1,336		3,148	3,274
Operating Segments | Wholesale Gas Services | SOUTHERN Co GAS | Intercompany Revenues
Segment Reporting Information [Line Items]
Operating revenues	63		102		151	269
Operating Segments | Wholesale Gas Services | SOUTHERN Co GAS | Total Gross Revenues
Segment Reporting Information [Line Items]
Operating revenues	1,286		1,438		3,299	3,543
Operating Segments | Gas Marketing Services | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	58		89		287	359
Segment net income (loss)	(3)		(76)		58	(63)
Total assets	1,527				1,527		1,587
Eliminations
Segment Reporting Information [Line Items]
Operating revenues	(67)		(49)		(106)	(100)
Segment net income (loss)	(9)		3		(11)	4
Goodwill	0				0		0
Total assets	(1,286)				(1,286)		(1,778)
Eliminations | SOUTHERN Co GAS
Segment Reporting Information [Line Items]
Operating revenues	(6)		(5)		(38)	(38)
Segment net income (loss)	0		0		0	0
Total assets	(11,533)				(11,533)		(11,582)
Eliminations | Electric Utilities
Segment Reporting Information [Line Items]
Operating revenues	(119)		(114)		(211)	(220)
Segment net income (loss)	0		$ 0		0	$ 0
Goodwill	0				0		0
Total assets	$ (783)				$ (783)		$ (306)

Segment and Related Informati_5

Segment and Related Information - Financial Data for Products and Services (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Concentration Risk [Line Items]
Operating revenues	$ 5,098	$ 5,627	$ 10,510	$ 11,999
Retail
Concentration Risk [Line Items]
Operating revenues	3,540	3,740	6,623	7,308
Wholesale
Concentration Risk [Line Items]
Operating revenues	542	616	1,041	1,239
Other
Concentration Risk [Line Items]
Operating revenues	161	170	331	330
Gas Distribution Operations
Concentration Risk [Line Items]
Operating revenues	562	642	1,724	1,865
Electric Utilities' Revenues
Concentration Risk [Line Items]
Operating revenues	4,290	4,565	8,085	8,948
Electric Utilities' Revenues | Retail
Concentration Risk [Line Items]
Operating revenues	3,540	3,740	6,623	7,308
Electric Utilities' Revenues | Wholesale
Concentration Risk [Line Items]
Operating revenues	542	616	1,041	1,239
Electric Utilities' Revenues | Other
Concentration Risk [Line Items]
Operating revenues	208	209	421	401
Southern Company Gas' Revenues
Concentration Risk [Line Items]
Operating revenues	689	730	2,163	2,369
Southern Company Gas' Revenues | Gas Distribution Operations
Concentration Risk [Line Items]
Operating revenues	563	638	1,724	1,838
Southern Company Gas' Revenues | Gas Distribution Operations | Revenues | Product Concentration Risk | Three Gas Distribution Operations
Concentration Risk [Line Items]
Operating revenues		70		237
Southern Company Gas' Revenues | Gas Marketing Services
Concentration Risk [Line Items]
Operating revenues	58	89	287	359
Southern Company Gas' Revenues | Gas Marketing Services | Revenues | Product Concentration Risk | Pivotal Home Solutions
Concentration Risk [Line Items]
Operating revenues		24		55
Southern Company Gas' Revenues | Other
Concentration Risk [Line Items]
Operating revenues	$ 68	$ 3	$ 152	$ 172