Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Operating Revenues:
Operating revenues	$ 5,910	$ 5,018
Operating Expenses:
Total cost of sales	583	439
Other operations and maintenance	1,372	1,296
Depreciation and amortization	871	857
Taxes other than income taxes	345	330
Estimated loss on Plant Vogtle Units 3 and 4	48	0
(Gain) loss on dispositions, net	(44)	(39)
Total operating expenses	4,312	3,755
Operating Income	1,598	1,263
Other Income and (Expense):
Allowance for equity funds used during construction	46	34
Earnings from equity method investments	45	42
Interest expense, net of amounts capitalized	(450)	(456)
Other income (expense), net	58	103
Total other income and (expense)	(301)	(277)
Earnings Before Income Taxes	1,297	986
Income taxes (benefit)	190	145
Comprehensive Income	1,135	794
Consolidated Net Income	1,107	841
Dividends on preferred stock of subsidiaries	4	4
Net loss attributable to noncontrolling interests	(32)	(31)
Net Income	$ 1,135	$ 868
Earnings per share -
Basic (in dollars per share)	$ 1.07	$ 0.82
Diluted (in dollars per share)	$ 1.06	$ 0.81
Average number of shares of common stock outstanding (in millions)
Basic (in shares)	1,060	1,057
Diluted (in shares)	1,066	1,067
Retail electric revenues
Operating Revenues:
Operating revenues	$ 3,342	$ 3,078
Wholesale electric revenues
Operating Revenues:
Operating revenues	545	418
Other electric revenues
Operating Revenues:
Operating revenues	170	151
Natural gas
Operating Revenues:
Operating revenues	1,694	1,249
Operating Expenses:
Total cost of sales	583	439
Other
Operating Revenues:
Operating revenues	159	122
Operating Expenses:
Total cost of sales	82	55
Fuel
Operating Expenses:
Total cost of sales	848	636
Purchased power
Operating Expenses:
Total cost of sales	207	181
Alternative revenue programs
Operating Revenues:
Operating revenues	2	9
ALABAMA POWER CO
Operating Revenues:
Operating revenues	1,559	1,351
Operating Expenses:
Other operations and maintenance	361	350
Depreciation and amortization	211	200
Taxes other than income taxes	103	106
Total operating expenses	1,046	929
Operating Income	513	422
Other Income and (Expense):
Allowance for equity funds used during construction	12	10
Interest expense, net of amounts capitalized	(84)	(88)
Other income (expense), net	32	24
Total other income and (expense)	(40)	(54)
Earnings Before Income Taxes	473	368
Income taxes (benefit)	110	84
Comprehensive Income	364	285
Consolidated Net Income	363	284
Dividends on preferred stock of subsidiaries	4	4
Net Income	359	280
ALABAMA POWER CO | Retail electric revenues
Operating Revenues:
Operating revenues	1,352	1,205
ALABAMA POWER CO | Wholesale electric revenues
Operating Revenues:
Operating revenues	92	56
ALABAMA POWER CO | Wholesale revenues, affiliates
Operating Revenues:
Operating revenues	32	19
ALABAMA POWER CO | Other
Operating Revenues:
Operating revenues	83	71
ALABAMA POWER CO | Fuel
Operating Expenses:
Total cost of sales	291	215
ALABAMA POWER CO | Purchased power
Operating Expenses:
Total cost of sales	50	40
ALABAMA POWER CO | Purchased power, affiliates
Operating Expenses:
Total cost of sales	30	18
GEORGIA POWER CO
Operating Revenues:
Operating revenues	1,970	1,825
Operating Expenses:
Other operations and maintenance	474	465
Depreciation and amortization	338	352
Taxes other than income taxes	116	113
Estimated loss on Plant Vogtle Units 3 and 4	48	0
Total operating expenses	1,569	1,419
Operating Income	401	406
Other Income and (Expense):
Interest expense, net of amounts capitalized	(104)	(111)
Other income (expense), net	72	52
Total other income and (expense)	(32)	(59)
Earnings Before Income Taxes	369	347
Income taxes (benefit)	18	16
Comprehensive Income	353	330
Consolidated Net Income	351	331
GEORGIA POWER CO | Retail electric revenues
Operating Revenues:
Operating revenues	1,787	1,675
GEORGIA POWER CO | Wholesale electric revenues
Operating Revenues:
Operating revenues	43	26
GEORGIA POWER CO | Other
Operating Revenues:
Operating revenues	140	124
GEORGIA POWER CO | Fuel
Operating Expenses:
Total cost of sales	313	231
GEORGIA POWER CO | Purchased power
Operating Expenses:
Total cost of sales	144	129
GEORGIA POWER CO | Purchased power, affiliates
Operating Expenses:
Total cost of sales	136	129
MISSISSIPPI POWER CO
Operating Revenues:
Operating revenues	307	277
Operating Expenses:
Other operations and maintenance	68	76
Depreciation and amortization	47	42
Taxes other than income taxes	31	29
Total operating expenses	252	231
Operating Income	55	46
Other Income and (Expense):
Interest expense, net of amounts capitalized	(14)	(16)
Other income (expense), net	8	8
Total other income and (expense)	(6)	(8)
Earnings Before Income Taxes	49	38
Income taxes (benefit)	4	6
Comprehensive Income	45	32
Consolidated Net Income	45	32
MISSISSIPPI POWER CO | Retail electric revenues
Operating Revenues:
Operating revenues	204	199
MISSISSIPPI POWER CO | Wholesale electric revenues
Operating Revenues:
Operating revenues	63	51
MISSISSIPPI POWER CO | Wholesale revenues, affiliates
Operating Revenues:
Operating revenues	33	21
MISSISSIPPI POWER CO | Other
Operating Revenues:
Operating revenues	7	6
MISSISSIPPI POWER CO | Fuel
Operating Expenses:
Total cost of sales	101	79
MISSISSIPPI POWER CO | Purchased power
Operating Expenses:
Total cost of sales	5	5
SOUTHERN POWER CO
Operating Revenues:
Operating revenues	440	375
Operating Expenses:
Other operations and maintenance	101	79
Depreciation and amortization	119	117
Taxes other than income taxes	12	9
(Gain) loss on dispositions, net	(39)	(39)
Total operating expenses	354	287
Operating Income	86	88
Other Income and (Expense):
Interest expense, net of amounts capitalized	(38)	(39)
Other income (expense), net	7	2
Total other income and (expense)	(31)	(37)
Earnings Before Income Taxes	55	51
Income taxes (benefit)	(10)	7
Comprehensive Income	81	11
Consolidated Net Income	65	44
Net loss attributable to noncontrolling interests	(32)	(31)
Net Income	97	75
SOUTHERN POWER CO | Wholesale electric revenues
Operating Revenues:
Operating revenues	355	286
SOUTHERN POWER CO | Wholesale revenues, affiliates
Operating Revenues:
Operating revenues	81	86
SOUTHERN POWER CO | Other
Operating Revenues:
Operating revenues	4	3
SOUTHERN POWER CO | Fuel
Operating Expenses:
Total cost of sales	141	107
SOUTHERN POWER CO | Purchased power
Operating Expenses:
Total cost of sales	20	14
SOUTHERN Co GAS
Operating Revenues:
Operating revenues	$ 1,694	$ 1,249
Operating Expenses:
Cost, Product and Service [Extensible List]	Natural gas	Natural gas
Other operations and maintenance	$ 299	$ 258
Depreciation and amortization	130	120
Taxes other than income taxes	81	72
Total operating expenses	1,093	889
Operating Income	601	360
Other Income and (Expense):
Earnings from equity method investments	41	43
Interest expense, net of amounts capitalized	(60)	(58)
Other income (expense), net	(63)	9
Total other income and (expense)	(82)	(6)
Earnings Before Income Taxes	519	354
Income taxes (benefit)	121	79
Comprehensive Income	402	260
Consolidated Net Income	398	275
Net Income	398	275
SOUTHERN Co GAS | Natural gas
Operating Revenues:
Operating revenues	1,692	1,240
Operating Expenses:
Total cost of sales	583	439
SOUTHERN Co GAS | Alternative revenue programs
Operating Revenues:
Operating revenues	$ 2	$ 9