Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating Revenues:
Total operating revenues	$ 5,995	$ 6,159	$ 16,505	$ 18,158
Operating Expenses:
Other operations and maintenance	1,292	1,404	3,888	4,217
Depreciation and amortization	760	787	2,267	2,338
Taxes other than income taxes	303	319	931	990
Estimated loss on plants under construction	4	1	10	1,105
Impairment charges	110	36	142	197
(Gain) loss on dispositions, net	(6)	(353)	(2,512)	(317)
Total operating expenses	3,982	3,985	9,459	14,545
Operating Income (Loss)	2,013	2,174	7,046	3,613
Other Income and (Expense):
Allowance for equity funds used during construction	33	36	96	99
Earnings from equity method investments	39	36	120	108
Interest expense, net of amounts capitalized	(434)	(458)	(1,294)	(1,386)
Other income (expense), net	61	57	239	195
Total other income and (expense)	(301)	(329)	(839)	(984)
Earnings (Loss) Before Income Taxes	1,712	1,845	6,207	2,629
Income taxes	367	623	1,872	598
Consolidated Net Income	1,345	1,222	4,335	2,031
Dividends on preferred stock of subsidiaries	4	4	11	12
Net income attributable to noncontrolling interests	25	54	26	71
Net Income (Loss)	$ 1,316	$ 1,164	$ 4,298	$ 1,948
Earnings per share -
Basic (in dollars per share)	$ 1.26	$ 1.14	$ 4.12	$ 1.92
Diluted (in dollars per share)	$ 1.25	$ 1.13	$ 4.09	$ 1.91
Average number of shares of common stock outstanding (in millions)
Basic (in shares)	1,048	1,023	1,043	1,016
Diluted (in shares)	1,057	1,029	1,051	1,021
Retail electric revenues
Operating Revenues:
Total operating revenues	$ 4,512	$ 4,605	$ 11,136	$ 11,913
Wholesale electric revenues
Operating Revenues:
Total operating revenues	625	698	1,667	1,937
Other electric revenues
Operating Revenues:
Total operating revenues	163	165	492	495
Natural gas
Operating Revenues:
Total operating revenues	498	492	2,661	2,806
Operating Expenses:
Total cost of natural gas	79	104	956	1,053
Other
Operating Revenues:
Total operating revenues	197	199	549	1,007
Operating Expenses:
Total cost of natural gas	114	120	316	688
Fuel
Operating Expenses:
Total cost of natural gas	1,072	1,310	2,836	3,514
Purchased power
Operating Expenses:
Total cost of natural gas	254	257	625	760
Alternative revenue programs
Operating Revenues:
Total operating revenues	0	5	0	(23)
ALABAMA POWER CO
Operating Revenues:
Total operating revenues	1,841	1,740	4,762	4,716
Operating Expenses:
Other operations and maintenance	409	401	1,221	1,191
Depreciation and amortization	195	192	593	570
Taxes other than income taxes	101	97	301	289
Total operating expenses	1,165	1,179	3,303	3,403
Operating Income (Loss)	676	561	1,459	1,313
Other Income and (Expense):
Allowance for equity funds used during construction	13	16	41	43
Interest expense, net of amounts capitalized	(83)	(82)	(248)	(240)
Other income (expense), net	11	9	36	24
Total other income and (expense)	(59)	(57)	(171)	(173)
Earnings (Loss) Before Income Taxes	617	504	1,288	1,140
Income taxes	144	127	295	272
Consolidated Net Income	473	377	993	868
Dividends on preferred stock of subsidiaries	4	4	11	11
Net Income (Loss)	469	373	982	857
ALABAMA POWER CO | Retail electric revenues
Operating Revenues:
Total operating revenues	1,694	1,584	4,286	4,208
ALABAMA POWER CO | Wholesale electric revenues
Operating Revenues:
Total operating revenues	71	74	194	213
ALABAMA POWER CO | Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	2	14	66	96
ALABAMA POWER CO | Other
Operating Revenues:
Total operating revenues	74	68	216	199
ALABAMA POWER CO | Fuel
Operating Expenses:
Total cost of natural gas	310	356	864	1,028
ALABAMA POWER CO | Purchased power
Operating Expenses:
Total cost of natural gas	77	64	160	176
ALABAMA POWER CO | Purchased power, affiliates
Operating Expenses:
Total cost of natural gas	73	69	164	149
GEORGIA POWER CO
Operating Revenues:
Total operating revenues	2,755	2,593	6,706	6,601
Operating Expenses:
Other operations and maintenance	473	460	1,385	1,325
Depreciation and amortization	250	232	733	690
Taxes other than income taxes	127	118	348	332
Estimated loss on plants under construction	0	0	0	1,060
Total operating expenses	1,594	1,602	4,451	5,569
Operating Income (Loss)	1,161	991	2,255	1,032
Other Income and (Expense):
Allowance for equity funds used during construction			49	50
Interest expense, net of amounts capitalized	(103)	(95)	(304)	(303)
Other income (expense), net	36	30	113	104
Total other income and (expense)	(67)	(65)	(191)	(199)
Earnings (Loss) Before Income Taxes	1,094	926	2,064	833
Income taxes	255	262	466	212
Consolidated Net Income	839	664	1,598	621
Net Income (Loss)	839	664
GEORGIA POWER CO | Retail electric revenues
Operating Revenues:
Total operating revenues	2,567	2,425	6,181	6,112
GEORGIA POWER CO | Wholesale electric revenues
Operating Revenues:
Total operating revenues	36	43	98	123
GEORGIA POWER CO | Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	3	4	9	17
GEORGIA POWER CO | Other
Operating Revenues:
Total operating revenues	149	121	418	349
GEORGIA POWER CO | Fuel
Operating Expenses:
Total cost of natural gas	443	480	1,132	1,269
GEORGIA POWER CO | Purchased power
Operating Expenses:
Total cost of natural gas	151	106	393	338
GEORGIA POWER CO | Purchased power, affiliates
Operating Expenses:
Total cost of natural gas	150	206	460	555
MISSISSIPPI POWER CO
Operating Revenues:
Total operating revenues	370	358	970	956
Operating Expenses:
Other operations and maintenance	68	80	194	222
Depreciation and amortization	48	42	144	126
Taxes other than income taxes	30	28	85	83
Estimated loss on plants under construction	4	1	10	45
Total operating expenses	277	278	767	815
Operating Income (Loss)	93	80	203	141
Other Income and (Expense):
Interest expense, net of amounts capitalized	(17)	(19)	(52)	(59)
Other income (expense), net	4	0	15	28
Total other income and (expense)	(13)	(19)	(37)	(31)
Earnings (Loss) Before Income Taxes	80	61	166	110
Income taxes	15	14	27	23
Consolidated Net Income	65	47	139	87
Dividends on preferred stock of subsidiaries	0	0	0	1
Net Income (Loss)	65	47	139	86
MISSISSIPPI POWER CO | Retail electric revenues
Operating Revenues:
Total operating revenues	251	254	669	660
MISSISSIPPI POWER CO | Wholesale electric revenues
Operating Revenues:
Total operating revenues	64	70	178	197
MISSISSIPPI POWER CO | Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	51	28	109	81
MISSISSIPPI POWER CO | Other
Operating Revenues:
Total operating revenues	4	6	14	18
MISSISSIPPI POWER CO | Fuel
Operating Expenses:
Total cost of natural gas	121	116	319	312
MISSISSIPPI POWER CO | Purchased power
Operating Expenses:
Total cost of natural gas	6	11	15	27
SOUTHERN POWER CO
Operating Revenues:
Total operating revenues	574	635	1,527	1,699
Operating Expenses:
Other operations and maintenance	85	94	250	278
Depreciation and amortization	120	130	357	370
Taxes other than income taxes	10	12	32	36
Impairment charges	0	36	0	155
(Gain) loss on dispositions, net	0	0	(23)	0
Total operating expenses	407	499	1,147	1,487
Operating Income (Loss)	167	136	380	212
Other Income and (Expense):
Interest expense, net of amounts capitalized	(43)	(45)	(127)	(138)
Other income (expense), net	6	17	48	22
Total other income and (expense)	(37)	(28)	(79)	(116)
Earnings (Loss) Before Income Taxes	130	108	301	96
Income taxes	19	(38)	(41)	(210)
Consolidated Net Income	111	146	342	306
Net income attributable to noncontrolling interests	25	54	26	71
Net Income (Loss)	86	92	316	235
SOUTHERN POWER CO | Wholesale electric revenues
Operating Revenues:
Total operating revenues	455	496	1,197	1,363
SOUTHERN POWER CO | Wholesale revenues, affiliates
Operating Revenues:
Total operating revenues	116	134	320	326
SOUTHERN POWER CO | Other
Operating Revenues:
Total operating revenues	3	5	10	10
SOUTHERN POWER CO | Fuel
Operating Expenses:
Total cost of natural gas	166	190	449	511
SOUTHERN POWER CO | Purchased power
Operating Expenses:
Total cost of natural gas	26	37	82	137
SOUTHERN Co GAS
Operating Revenues:
Total operating revenues	498	492	2,661	2,861
Operating Expenses:
Other operations and maintenance	208	216	642	730
Depreciation and amortization	121	119	359	374
Taxes other than income taxes	33	32	161	157
Impairment charges	92	0	92	42
(Gain) loss on dispositions, net	0	(353)	0	(317)
Total operating expenses	533	118	2,210	2,051
Operating Income (Loss)	(35)	374	451	810
Other Income and (Expense):
Earnings from equity method investments	35	34	115	108
Interest expense, net of amounts capitalized	(56)	(52)	(174)	(170)
Other income (expense), net	5	6	16	21
Total other income and (expense)	(16)	(12)	(43)	(41)
Earnings (Loss) Before Income Taxes	(51)	362	408	769
Income taxes	(22)	316	61	475
Consolidated Net Income	(29)	46	347	294
Net Income (Loss)	(29)	46	347	294
SOUTHERN Co GAS | Natural gas
Operating Revenues:
Total operating revenues	498	487	2,661	2,829
Operating Expenses:
Total cost of natural gas	79	104	956	1,053
SOUTHERN Co GAS | Other
Operating Revenues:
Total operating revenues	0	0	0	55
Operating Expenses:
Total cost of natural gas	0	0	0	12
SOUTHERN Co GAS | Alternative revenue programs
Operating Revenues:
Total operating revenues	$ 0	$ 5	$ 0	$ (23)