Condensed Consolidated Statements of Income (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Operating Revenues:
Retail electric revenues	$ 3,394	$ 3,377
Wholesale electric revenues	531	396
Other electric revenues	175	181
Natural gas revenues	1,530	0
Other revenues	141	38
Total operating revenues	5,771	3,992
Operating Expenses:
Fuel	996	911
Purchased power	179	165
Cost of natural gas	719	0
Cost of other sales	88	19
Other operations and maintenance	1,329	1,107
Depreciation and amortization	716	541
Taxes other than income taxes	330	256
Estimated loss on Kemper IGCC	108	53
Total operating expenses	4,465	3,052
Operating Income	1,306	940
Other Income and (Expense):
Allowance for equity funds used during construction	57	53
Earnings from equity method investments	39	0
Interest expense, net of amounts capitalized	(416)	(246)
Other income (expense), net	(6)	(29)
Total other income and (expense)	(326)	(222)
Earnings Before Income Taxes	980	718
Income taxes	315	217
Consolidated Net Income	665	501
Dividends on preferred and preference stock of subsidiaries	11	11
Net income (loss) attributable to noncontrolling interests	(4)	1
Consolidated Net Income Attributable to Southern Company	$ 658	$ 489
Earnings per share (EPS) —
Basic EPS (in dollars per share)	$ 0.66	$ 0.53
Diluted EPS (in dollars per share)	$ 0.66	$ 0.53
Average number of shares of common stock outstanding (in millions)
Basic (in shares)	993	916
Diluted (in shares)	1,000	922
Cash dividends paid per share of common stock (in dollars per share)	$ 0.5600	$ 0.5425
Alabama Power [Member]
Operating Revenues:
Retail electric revenues	$ 1,227	$ 1,193
Wholesale revenues, non-affiliates	66	63
Wholesale revenues, affiliates	33	22
Other revenues	56	53
Total operating revenues	1,382	1,331
Operating Expenses:
Fuel	298	268
Purchased power, non-affiliates	34	36
Purchased power, affiliates	28	33
Other operations and maintenance	369	392
Depreciation and amortization	181	172
Taxes other than income taxes	96	97
Total operating expenses	1,006	998
Operating Income	376	333
Other Income and (Expense):
Allowance for equity funds used during construction	8	10
Interest expense, net of amounts capitalized	(75)	(73)
Other income (expense), net	(5)	(8)
Total other income and (expense)	(72)	(71)
Earnings Before Income Taxes	304	262
Income taxes	126	102
Consolidated Net Income	178	160
Dividends on preferred and preference stock of subsidiaries	4	4
Consolidated Net Income Attributable to Southern Company	174	156
Georgia Power [Member]
Operating Revenues:
Retail electric revenues	1,689	1,717
Wholesale revenues, non-affiliates	39	41
Wholesale revenues, affiliates	8	5
Other revenues	96	109
Total operating revenues	1,832	1,872
Operating Expenses:
Fuel	371	376
Purchased power, non-affiliates	88	83
Purchased power, affiliates	172	139
Other operations and maintenance	381	457
Depreciation and amortization	221	211
Taxes other than income taxes	98	97
Total operating expenses	1,331	1,363
Operating Income	501	509
Other Income and (Expense):
Allowance for equity funds used during construction	13	14
Interest expense, net of amounts capitalized	(101)	(94)
Other income (expense), net	20	17
Total other income and (expense)	(81)	(77)
Earnings Before Income Taxes	420	432
Income taxes	156	159
Consolidated Net Income	264	273
Dividends on preferred and preference stock of subsidiaries	4	4
Consolidated Net Income Attributable to Southern Company	260	269
Gulf Power [Member]
Operating Revenues:
Retail electric revenues	279	283
Wholesale revenues, non-affiliates	17	16
Wholesale revenues, affiliates	37	21
Other revenues	17	15
Total operating revenues	350	335
Operating Expenses:
Fuel	108	94
Purchased power, non-affiliates	32	30
Purchased power, affiliates	2	2
Other operations and maintenance	84	77
Depreciation and amortization	18	38
Taxes other than income taxes	27	29
Loss on Plant Scherer Unit 3	33	0
Total operating expenses	304	270
Operating Income	46	65
Other Income and (Expense):
Interest expense, net of amounts capitalized	(12)	(13)
Other income (expense), net	0	(1)
Total other income and (expense)	(12)	(14)
Earnings Before Income Taxes	34	51
Income taxes	14	20
Consolidated Net Income	20	31
Dividends on preferred and preference stock of subsidiaries	2	2
Consolidated Net Income Attributable to Southern Company	18	29
Mississippi Power [Member]
Operating Revenues:
Retail electric revenues	200	183
Wholesale revenues, non-affiliates	62	60
Wholesale revenues, affiliates	5	9
Other revenues	5	5
Total operating revenues	272	257
Operating Expenses:
Fuel	78	76
Purchased power, non-affiliates	1	0
Purchased power, affiliates	7	5
Other operations and maintenance	74	69
Depreciation and amortization	40	38
Taxes other than income taxes	26	26
Estimated loss on Kemper IGCC	108	53
Total operating expenses	334	267
Operating Income	(62)	(10)
Other Income and (Expense):
Allowance for equity funds used during construction	35	29
Interest expense, net of amounts capitalized	(19)	(16)
Other income (expense), net	(1)	(2)
Total other income and (expense)	15	11
Earnings Before Income Taxes	(47)	1
Income taxes	(27)	(10)
Consolidated Net Income	(20)	11
Dividends on preferred and preference stock of subsidiaries	0	0
Consolidated Net Income Attributable to Southern Company	(20)	11
Southern Power [Member]
Operating Revenues:
Wholesale revenues, non-affiliates	347	215
Wholesale revenues, affiliates	100	97
Other revenues	3	3
Total operating revenues	450	315
Operating Expenses:
Fuel	132	91
Purchased power, non-affiliates	25	13
Purchased power, affiliates	5	6
Other operations and maintenance	92	79
Depreciation and amortization	119	73
Taxes other than income taxes	12	6
Total operating expenses	385	268
Operating Income	65	47
Other Income and (Expense):
Interest expense, net of amounts capitalized	(50)	(21)
Other income (expense), net	(1)	2
Total other income and (expense)	(51)	(19)
Earnings Before Income Taxes	14	28
Income taxes	(52)	(23)
Consolidated Net Income	66	51
Net income (loss) attributable to noncontrolling interests	(4)	1
Consolidated Net Income Attributable to Southern Company	70	50
Southern Company Gas [Member]
Operating Revenues:
Natural gas revenues	1,530
Other revenues	30
Total operating revenues	1,560
Operating Expenses:
Cost of natural gas	719
Cost of other sales	7
Other operations and maintenance	253
Depreciation and amortization	120
Merger-related expenses	0
Taxes other than income taxes	70
Total operating expenses	1,169
Operating Income	391
Other Income and (Expense):
Earnings from equity method investments	39
Interest expense, net of amounts capitalized	(46)
Other income (expense), net	5
Total other income and (expense)	(2)
Earnings Before Income Taxes	389
Income taxes	150
Consolidated Net Income	239
Net income (loss) attributable to noncontrolling interests	0
Consolidated Net Income Attributable to Southern Company	$ 239
Predecessor [Member] | Southern Company Gas [Member]
Operating Revenues:
Natural gas revenues		1,302
Other revenues		32
Total operating revenues		1,334
Operating Expenses:
Cost of natural gas		571
Cost of other sales		7
Other operations and maintenance		241
Depreciation and amortization		102
Merger-related expenses		3
Taxes other than income taxes		62
Total operating expenses		986
Operating Income		348
Other Income and (Expense):
Earnings from equity method investments		1
Interest expense, net of amounts capitalized		(48)
Other income (expense), net		3
Total other income and (expense)		(44)
Earnings Before Income Taxes		304
Income taxes		111
Consolidated Net Income		193
Net income (loss) attributable to noncontrolling interests		11
Consolidated Net Income Attributable to Southern Company		$ 182