Consolidated Statements of Common Stockholders Equity (USD $) Share data in Thousands	Total	Common Stock	Paid In Capital	Treasury Stock	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Preferred and Preference Stock of Subsidiaries	Alabama Power [Member]	Alabama Power [Member] Common Stock	Alabama Power [Member] Paid In Capital	Alabama Power [Member] Retained Earnings	Alabama Power [Member] Accumulated Other Comprehensive Income (Loss)	Georgia Power [Member]	Georgia Power [Member] Common Stock	Georgia Power [Member] Paid In Capital	Georgia Power [Member] Retained Earnings	Georgia Power [Member] Accumulated Other Comprehensive Income (Loss)	Gulf Power [Member]	Gulf Power [Member] Common Stock	Gulf Power [Member] Paid In Capital	Gulf Power [Member] Retained Earnings	Gulf Power [Member] Accumulated Other Comprehensive Income (Loss)	Mississippi Power [Member]	Mississippi Power [Member] Common Stock	Mississippi Power [Member] Paid In Capital	Mississippi Power [Member] Retained Earnings	Mississippi Power [Member] Accumulated Other Comprehensive Income (Loss)	Southern Power [Member]	Southern Power [Member] Common Stock	Southern Power [Member] Paid In Capital	Southern Power [Member] Retained Earnings	Southern Power [Member] Accumulated Other Comprehensive Income (Loss)
Beginning Balance at Dec. 31, 2008	$ 13,983,000,000	$ 3,888,000,000	$ 1,893,000,000	$ (12,000,000)	$ 7,612,000,000	$ (105,000,000)	$ 707,000,000	$ 4,854,000,000	$ 1,019,000,000	$ 2,091,000,000	$ 1,754,000,000	$ (10,000,000)	$ 6,879,000,000	$ 398,000,000	$ 3,656,000,000	$ 2,858,000,000	$ (33,000,000)	$ 822,092,000	$ 118,060,000	$ 511,547,000	$ 197,417,000	$ (4,932,000)	$ 636,451,000	$ 37,691,000	$ 319,958,000	$ 278,802,000	$ 0	$ 1,138,361,000	$ 0	$ 862,109,000	$ 302,309,000	$ (26,057,000)
Beginning Balance, Shares at Dec. 31, 2008		777,616		(424)					25,000					9,000					1,793					1,121					1
Net income after dividends on preferred and preference stock of subsidiaries	1,643,000,000				1,643,000,000			670,000,000			670,000,000		814,000,000			814,000,000		111,233,000			111,233,000		84,967,000			84,967,000
Net income	1,708,000,000							709,000,000					831,000,000					117,436,000					86,700,000					155,852,000			155,852,000
Capital contributions from parent company								28,000,000		28,000,000			937,000,000		937,000,000			23,030,000		23,030,000			5,604,000		5,604,000			2,353,000		2,353,000
Other comprehensive income (loss)	17,000,000					17,000,000		5,000,000				5,000,000	12,000,000				12,000,000	2,470,000				2,470,000						4,656,000				4,656,000
Stock issued	1,287,000,000	213,000,000	1,074,000,000					203,000,000	203,000,000									135,000,000	135,000,000
Stock issued, shares		42,536							5,000										1,350
Stock-based compensation	26,000,000		26,000,000
Cash dividends on common stock	(1,369,000,000)				(1,369,000,000)			(523,000,000)			(523,000,000)		(739,000,000)			(739,000,000)		(89,300,000)			(89,300,000)		(68,500,000)			(68,500,000)		(106,100,000)			(106,100,000)
Other	(2,000,000)		2,000,000	(3,000,000)	(1,000,000)
Other, shares				(81)					1,000
Change in benefit plan measurement date																		(233,000)			(233,000)
Ending Balance at Dec. 31, 2009	15,585,000,000	4,101,000,000	2,995,000,000	(15,000,000)	7,885,000,000	(88,000,000)	707,000,000	5,237,000,000	1,222,000,000	2,119,000,000	1,901,000,000	(5,000,000)	7,903,000,000	398,000,000	4,593,000,000	2,933,000,000	(21,000,000)	1,004,292,000	253,060,000	534,577,000	219,117,000	(2,462,000)	658,522,000	37,691,000	325,562,000	295,269,000	0	1,195,122,000	0	864,462,000	352,061,000	(21,401,000)
Ending Balance, Shares at Dec. 31, 2009		820,152		(505)					31,000					9,000					3,143					1,121					1
Net income after dividends on preferred and preference stock of subsidiaries	1,975,000,000				1,975,000,000			707,000,000			707,000,000		950,000,000			950,000,000		121,511,000			121,511,000		80,217,000			80,217,000
Net income	2,040,000,000							746,000,000					967,000,000					127,714,000					81,950,000					131,309,000			131,309,000
Capital contributions from parent company								37,000,000		37,000,000			698,000,000		698,000,000			3,798,000		3,798,000			67,228,000		67,228,000			36,507,000		36,507,000
Other comprehensive income (loss)	18,000,000					18,000,000		(2,000,000)				(2,000,000)	10,000,000				10,000,000	(265,000)				(265,000)	2,000				2,000	7,382,000				7,382,000
Stock issued	772,000,000	118,000,000	654,000,000															50,000,000	50,000,000
Stock issued, shares		23,662																	500
Stock-based compensation	52,000,000		52,000,000
Cash dividends on common stock	(1,496,000,000)				(1,496,000,000)			(586,000,000)			(586,000,000)		(820,000,000)			(820,000,000)		(104,300,000)			(104,300,000)		(68,600,000)			(68,600,000)		(107,100,000)			(107,100,000)
Other	3,000,000		1,000,000		2,000,000																		(1,000)			(1,000)
Other, shares				31
Ending Balance at Dec. 31, 2010	16,909,000,000	4,219,000,000	3,702,000,000	(15,000,000)	8,366,000,000	(70,000,000)	707,000,000	5,393,000,000	1,222,000,000	2,156,000,000	2,022,000,000	(7,000,000)	8,741,000,000	398,000,000	5,291,000,000	3,063,000,000	(11,000,000)	1,075,036,000	303,060,000	538,375,000	236,328,000	(2,727,000)	737,368,000	37,691,000	392,790,000	306,885,000	2,000	1,263,220,000	0	900,969,000	376,270,000	(14,019,000)
Ending Balance, Shares at Dec. 31, 2010		843,814		(474)					31,000					9,000					3,643					1,121					1
Net income after dividends on preferred and preference stock of subsidiaries	2,203,000,000				2,203,000,000			708,000,000			708,000,000		1,145,000,000			1,145,000,000		105,005,000			105,005,000		94,182,000			94,182,000
Net income	2,268,000,000							747,000,000					1,162,000,000					111,208,000					95,915,000					162,231,000			162,231,000
Capital contributions from parent company								26,000,000		26,000,000			231,000,000		231,000,000			4,334,000		4,334,000			302,065,000		302,065,000			127,241,000		127,241,000
Other comprehensive income (loss)	(41,000,000)					(41,000,000)		(11,000,000)				(11,000,000)	2,000,000				2,000,000	573,000				573,000	(8,899,000)				(8,899,000)	7,190,000				7,190,000
Stock issued	725,000,000	109,000,000	616,000,000															50,000,000	50,000,000
Stock issued, shares		21,850																	500
Stock-based compensation	89,000,000		89,000,000
Cash dividends on common stock	(1,601,000,000)				(1,601,000,000)			(774,000,000)			(774,000,000)		(1,096,000,000)			(1,096,000,000)		(110,000,000)			(110,000,000)		(75,500,000)			(75,500,000)		(91,200,000)			(91,200,000)
Other	1,000,000		3,000,000	(2,000,000)																			1,000			1,000
Other, shares				(65)
Ending Balance at Dec. 31, 2011	$ 18,285,000,000	$ 4,328,000,000	$ 4,410,000,000	$ (17,000,000)	$ 8,968,000,000	$ (111,000,000)	$ 707,000,000	$ 5,342,000,000	$ 1,222,000,000	$ 2,182,000,000	$ 1,956,000,000	$ (18,000,000)	$ 9,023,000,000	$ 398,000,000	$ 5,522,000,000	$ 3,112,000,000	$ (9,000,000)	$ 1,124,948,000	$ 353,060,000	$ 542,709,000	$ 231,333,000	$ (2,154,000)	$ 1,049,217,000	$ 37,691,000	$ 694,855,000	$ 325,568,000	$ (8,897,000)	$ 1,468,682,000	$ 0	$ 1,028,210,000	$ 447,301,000	$ (6,829,000)
Ending Balance, Shares at Dec. 31, 2011		865,664		(539)					31,000					9,000					4,143					1,121					1