Condensed Consolidated Statements of Cash Flows (Unaudited) - USD ($)	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Operating Activities:
Net income (loss)	$ 1,133,000,000	$ 1,169,000,000
Adjustments to reconcile net income (loss) to net cash provided from operating activities —
Depreciation and amortization, total	1,306,000,000	1,171,000,000
Deferred income taxes	279,000,000	783,000,000
Allowance for equity funds used during construction	(98,000,000)	(102,000,000)
Stock based compensation expense	69,000,000	66,000,000
Hedge settlements	(201,000,000)	(3,000,000)
Estimated loss on Kemper IGCC	134,000,000	32,000,000
Income taxes receivable, non-current	0	(444,000,000)
Other, net	(69,000,000)	(3,000,000)
Changes in certain current assets and liabilities —
-Receivables	(197,000,000)	(158,000,000)
-Fossil fuel stock	70,000,000	136,000,000
-Other current assets	(53,000,000)	(99,000,000)
-Accounts payable	(71,000,000)	(311,000,000)
-Accrued taxes	74,000,000	(60,000,000)
-Accrued compensation	(222,000,000)	(269,000,000)
-Mirror CWIP	0	82,000,000
-Other current liabilities	(39,000,000)	117,000,000
Net cash provided from (used for) operating activities	2,115,000,000	2,107,000,000
Investing Activities:
Business acquisitions, net of cash acquired	(897,000,000)	(408,000,000)
Property additions	(3,486,000,000)	(2,239,000,000)
Investment in restricted cash	(8,608,000,000)	0
Distributions of restricted cash	649,000,000	0
Nuclear decommissioning trust fund purchases	(585,000,000)	(933,000,000)
Nuclear decommissioning trust fund sales	580,000,000	928,000,000
Cost of removal, net of salvage	(99,000,000)	(87,000,000)
Change in construction payables	(260,000,000)	56,000,000
Prepaid long-term service agreement	(82,000,000)	(110,000,000)
Other investing activities	113,000,000	27,000,000
Net cash used for investing activities	(12,675,000,000)	(2,766,000,000)
Financing Activities:
Increase (decrease) in notes payable, net	471,000,000	184,000,000
Proceeds —
Long-term debt issuances	12,038,000,000	3,075,000,000
Common stock issuances	1,383,000,000	116,000,000
Short-term borrowings	0	320,000,000
Redemptions and repurchases —
Long-term debt	(1,272,000,000)	(939,000,000)
Interest-bearing refundable deposits	0	(275,000,000)
Common stock	0	(115,000,000)
Preferred and preference stock	0	(412,000,000)
Short-term borrowings	(475,000,000)	(250,000,000)
Distributions to noncontrolling interests	(11,000,000)	(1,000,000)
Capital contributions from noncontrolling interests	179,000,000	78,000,000
Purchase of membership interests from noncontrolling interests	(129,000,000)	0
Payment of common stock dividends	(1,023,000,000)	(972,000,000)
Other financing activities	(108,000,000)	(47,000,000)
Net cash provided from (used for) financing activities	11,053,000,000	762,000,000
Net Change in Cash and Cash Equivalents	493,000,000	103,000,000
Cash and Cash Equivalents at Beginning of Period	1,404,000,000	710,000,000
Cash and Cash Equivalents at End of Period	1,897,000,000	813,000,000
Cash paid (received) during the period for --
Interest (net of capitalized amounts)	458,000,000	374,000,000
Income taxes, net	(138,000,000)	(16,000,000)
Noncash Investing and Financing Items [Abstract]
Noncash transactions - Accrued property additions at end of period	549,000,000	345,000,000
Alabama Power [Member]
Operating Activities:
Net income (loss)	376,000,000	386,000,000
Adjustments to reconcile net income (loss) to net cash provided from operating activities —
Depreciation and amortization, total	419,000,000	387,000,000
Deferred income taxes	175,000,000	60,000,000
Allowance for equity funds used during construction	(16,000,000)	(29,000,000)
Other, net	(37,000,000)	(23,000,000)
Changes in certain current assets and liabilities —
-Receivables	64,000,000	(115,000,000)
-Fossil fuel stock	(32,000,000)	19,000,000
-Other current assets	(67,000,000)	(52,000,000)
-Accounts payable	(75,000,000)	(212,000,000)
-Accrued taxes	98,000,000	177,000,000
-Accrued compensation	(50,000,000)	(66,000,000)
-Retail fuel cost over recovery - short-term	(60,000,000)	25,000,000
-Other current liabilities	8,000,000	40,000,000
Net cash provided from (used for) operating activities	803,000,000	597,000,000
Investing Activities:
Property additions	(645,000,000)	(612,000,000)
Nuclear decommissioning trust fund purchases	(200,000,000)	(278,000,000)
Nuclear decommissioning trust fund sales	200,000,000	278,000,000
Cost of removal, net of salvage	(51,000,000)	(28,000,000)
Change in construction payables	(27,000,000)	28,000,000
Other investing activities	(18,000,000)	(14,000,000)
Net cash used for investing activities	(741,000,000)	(626,000,000)
Proceeds —
Senior notes issuances	400,000,000	975,000,000
Capital contributions from parent company	237,000,000	10,000,000
Pollution control revenue bonds	0	80,000,000
Other long-term debt	45,000,000	0
Redemptions and repurchases —
Pollution control revenue bonds	0	(134,000,000)
Senior notes	(200,000,000)	(250,000,000)
Preferred and preference stock	0	(412,000,000)
Payment of common stock dividends	(382,000,000)	(286,000,000)
Other financing activities	(13,000,000)	(32,000,000)
Net cash provided from (used for) financing activities	87,000,000	(49,000,000)
Net Change in Cash and Cash Equivalents	149,000,000	(78,000,000)
Cash and Cash Equivalents at Beginning of Period	194,000,000	273,000,000
Cash and Cash Equivalents at End of Period	343,000,000	195,000,000
Cash paid (received) during the period for --
Interest (net of capitalized amounts)	131,000,000	118,000,000
Income taxes, net	(122,000,000)	47,000,000
Noncash Investing and Financing Items [Abstract]
Noncash transactions - Accrued property additions at end of period	94,000,000	35,000,000
Georgia Power [Member]
Operating Activities:
Net income (loss)	625,000,000	522,000,000
Adjustments to reconcile net income (loss) to net cash provided from operating activities —
Depreciation and amortization, total	530,000,000	512,000,000
Deferred income taxes	157,000,000	(6,000,000)
Allowance for equity funds used during construction	(24,000,000)	(10,000,000)
Deferred expenses	39,000,000	28,000,000
Contract amendment	0	(118,000,000)
Settlement of asset retirement obligations	(52,000,000)	(9,000,000)
Other, net	6,000,000	9,000,000
Changes in certain current assets and liabilities —
-Receivables	(25,000,000)	(21,000,000)
-Fossil fuel stock	61,000,000	101,000,000
-Prepaid income taxes	(1,000,000)	86,000,000
-Other current assets	11,000,000	(38,000,000)
-Accounts payable	6,000,000	(110,000,000)
-Accrued taxes	(137,000,000)	(125,000,000)
-Accrued compensation	(44,000,000)	(61,000,000)
-Other current liabilities	17,000,000	14,000,000
Net cash provided from (used for) operating activities	1,169,000,000	774,000,000
Investing Activities:
Property additions	(1,058,000,000)	(853,000,000)
Nuclear decommissioning trust fund purchases	(386,000,000)	(655,000,000)
Nuclear decommissioning trust fund sales	380,000,000	649,000,000
Cost of removal, net of salvage	(34,000,000)	(46,000,000)
Change in construction payables, net of joint owner portion	(75,000,000)	26,000,000
Prepaid long-term service agreement	(14,000,000)	(40,000,000)
Other investing activities	17,000,000	28,000,000
Net cash used for investing activities	(1,170,000,000)	(891,000,000)
Financing Activities:
Increase (decrease) in notes payable, net	39,000,000	44,000,000
Proceeds —
Senior notes issuances	650,000,000	0
FFB loan	300,000,000	600,000,000
Capital contributions from parent company	239,000,000	23,000,000
Pollution control revenue bonds	0	170,000,000
Short-term borrowings	0	250,000,000
Redemptions and repurchases —
Pollution control revenue bonds	(4,000,000)	(65,000,000)
Senior notes	(500,000,000)	(125,000,000)
Short-term borrowings	0	(250,000,000)
Payment of common stock dividends	(653,000,000)	(517,000,000)
Other financing activities	(16,000,000)	(13,000,000)
Net cash provided from (used for) financing activities	55,000,000	117,000,000
Net Change in Cash and Cash Equivalents	54,000,000	0
Cash and Cash Equivalents at Beginning of Period	67,000,000	24,000,000
Cash and Cash Equivalents at End of Period	121,000,000	24,000,000
Cash paid (received) during the period for --
Interest (net of capitalized amounts)	174,000,000	170,000,000
Income taxes, net	78,000,000	240,000,000
Noncash Investing and Financing Items [Abstract]
Noncash transactions - Accrued property additions at end of period	288,000,000	171,000,000
Gulf Power [Member]
Operating Activities:
Net income (loss)	68,000,000	77,000,000
Adjustments to reconcile net income (loss) to net cash provided from operating activities —
Depreciation and amortization, total	83,000,000	64,000,000
Deferred income taxes	16,000,000	40,000,000
Allowance for equity funds used during construction	0	(8,000,000)
Other, net	(3,000,000)	3,000,000
Changes in certain current assets and liabilities —
-Receivables	(6,000,000)	(15,000,000)
-Fossil fuel stock	34,000,000	6,000,000
-Prepaid income taxes	2,000,000	12,000,000
-Other current assets	(1,000,000)	1,000,000
-Accounts payable	(7,000,000)	(9,000,000)
-Accrued taxes	17,000,000	15,000,000
-Accrued compensation	(12,000,000)	(10,000,000)
-Other current liabilities	4,000,000	(1,000,000)
Net cash provided from (used for) operating activities	195,000,000	183,000,000
Investing Activities:
Property additions	(68,000,000)	(148,000,000)
Cost of removal, net of salvage	(4,000,000)	(7,000,000)
Change in construction payables	(7,000,000)	(15,000,000)
Other investing activities	(5,000,000)	(4,000,000)
Net cash used for investing activities	(84,000,000)	(174,000,000)
Financing Activities:
Increase (decrease) in notes payable, net	46,000,000	4,000,000
Proceeds —
Common stock issuances	0	20,000,000
Short-term borrowings	0	40,000,000
Redemptions and repurchases —
Senior notes	(125,000,000)	0
Payment of common stock dividends	(60,000,000)	(65,000,000)
Other financing activities	0	(3,000,000)
Net cash provided from (used for) financing activities	(139,000,000)	(4,000,000)
Net Change in Cash and Cash Equivalents	(28,000,000)	5,000,000
Cash and Cash Equivalents at Beginning of Period	74,000,000	39,000,000
Cash and Cash Equivalents at End of Period	46,000,000	44,000,000
Cash paid (received) during the period for --
Interest (net of capitalized amounts)	28,000,000	26,000,000
Income taxes, net	(3,000,000)	(9,000,000)
Noncash Investing and Financing Items [Abstract]
Noncash transactions - Accrued property additions at end of period	13,000,000	28,000,000
Mississippi Power [Member]
Operating Activities:
Net income (loss)	14,000,000	85,000,000
Adjustments to reconcile net income (loss) to net cash provided from operating activities —
Depreciation and amortization, total	82,000,000	55,000,000
Deferred income taxes	(16,000,000)	694,000,000
Investment tax credits	0	32,000,000
Allowance for equity funds used during construction	(59,000,000)	(53,000,000)
Regulatory assets associated with Kemper IGCC	(10,000,000)	(50,000,000)
Estimated loss on Kemper IGCC	134,000,000	32,000,000
Income taxes receivable, non-current	0	(544,000,000)
Other, net	3,000,000	8,000,000
Changes in certain current assets and liabilities —
-Receivables	15,000,000	6,000,000
-Fossil fuel stock	6,000,000	5,000,000
-Prepaid income taxes	34,000,000	24,000,000
-Other current assets	(3,000,000)	(7,000,000)
-Accounts payable	(12,000,000)	(25,000,000)
-Accrued taxes	19,000,000	(51,000,000)
-Accrued interest	0	(7,000,000)
-Accrued compensation	(12,000,000)	(12,000,000)
-Over recovered regulatory clause revenues	4,000,000	32,000,000
-Mirror CWIP	0	82,000,000
-Customer liability associated with Kemper refunds	(69,000,000)	0
-Other current liabilities	7,000,000	3,000,000
Net cash provided from (used for) operating activities	137,000,000	309,000,000
Investing Activities:
Property additions	(403,000,000)	(428,000,000)
Change in construction payables	(11,000,000)	(15,000,000)
Capital grant proceeds	137,000,000	0
Other investing activities	(19,000,000)	(17,000,000)
Net cash used for investing activities	(296,000,000)	(460,000,000)
Financing Activities:
Increase (decrease) in notes payable, net	0	475,000,000
Proceeds —
Capital contributions from parent company	226,000,000	77,000,000
Short-term borrowings	0	30,000,000
Long-term debt issuance to parent company	200,000,000	0
Other long-term debt	900,000,000	0
Redemptions and repurchases —
Short-term borrowings	(475,000,000)	0
Long-term debt to parent company	(225,000,000)	0
Other long-term debt	(425,000,000)	(350,000,000)
Other financing activities	(3,000,000)	(2,000,000)
Net cash provided from (used for) financing activities	198,000,000	230,000,000
Net Change in Cash and Cash Equivalents	39,000,000	79,000,000
Cash and Cash Equivalents at Beginning of Period	98,000,000	133,000,000
Cash and Cash Equivalents at End of Period	137,000,000	212,000,000
Cash paid (received) during the period for --
Interest (net of capitalized amounts)	26,000,000	2,000,000
Income taxes, net	(122,000,000)	(181,000,000)
Noncash Investing and Financing Items [Abstract]
Noncash transactions - Accrued property additions at end of period	94,000,000	99,000,000
Issuance of promissory note to parent related to repayment of interest-bearing refundable deposits and accrued interest	0	301,000,000
Southern Power [Member]
Operating Activities:
Net income (loss)	152,000,000	85,000,000
Adjustments to reconcile net income (loss) to net cash provided from operating activities —
Depreciation and amortization, total	159,000,000	121,000,000
Deferred income taxes	(71,000,000)	59,000,000
Investment tax credits	0	153,000,000
Amortization of investment tax credits	(15,000,000)	(10,000,000)
Deferred revenues	(31,000,000)	(21,000,000)
Accrued income taxes, non-current	0	100,000,000
Other, net	9,000,000	10,000,000
Changes in certain current assets and liabilities —
-Receivables	(76,000,000)	(26,000,000)
-Prepaid income taxes	(147,000,000)	(102,000,000)
-Other current assets	5,000,000	5,000,000
-Accounts payable	4,000,000	(31,000,000)
-Accrued taxes	62,000,000	(110,000,000)
-Other current liabilities	0	18,000,000
Net cash provided from (used for) operating activities	51,000,000	251,000,000
Investing Activities:
Business acquisitions, net of cash acquired	(502,000,000)	(408,000,000)
Property additions	(1,281,000,000)	(154,000,000)
Investment in restricted cash	(646,000,000)	0
Distributions of restricted cash	649,000,000	0
Change in construction payables	(137,000,000)	38,000,000
Payments pursuant to long-term service agreements	(43,000,000)	(45,000,000)
Other investing activities	(25,000,000)	(1,000,000)
Net cash used for investing activities	(1,985,000,000)	(570,000,000)
Financing Activities:
Increase (decrease) in notes payable, net	695,000,000	(195,000,000)
Proceeds —
Senior notes issuances	1,241,000,000	650,000,000
Capital contributions from parent company	300,000,000	0
Redemptions and repurchases —
Distributions to noncontrolling interests	(11,000,000)	(1,000,000)
Capital contributions from noncontrolling interests	179,000,000	78,000,000
Purchase of membership interests from noncontrolling interests	(129,000,000)	0
Payment of common stock dividends	(136,000,000)	(65,000,000)
Other financing activities	(13,000,000)	(3,000,000)
Net cash provided from (used for) financing activities	2,126,000,000	464,000,000
Net Change in Cash and Cash Equivalents	192,000,000	145,000,000
Cash and Cash Equivalents at Beginning of Period	830,000,000	75,000,000
Cash and Cash Equivalents at End of Period	1,022,000,000	220,000,000
Cash paid (received) during the period for --
Interest (net of capitalized amounts)	42,000,000	35,000,000
Income taxes, net	115,000,000	(72,000,000)
Noncash Investing and Financing Items [Abstract]
Noncash transactions - Accrued property additions at end of period	$ 108,000,000	$ 38,000,000