Quarterly Financial Information (Unaudited) (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Summarized quarterly financial information
Operating revenues	$ 3,927,000	$ 5,017,000	$ 4,246,000	$ 3,897,000	$ 3,703,000	$ 5,049,000	$ 4,181,000	$ 3,604,000	$ 17,087,000		$ 16,537,000		$ 17,657,000
Operating Income (Loss)	799,000	1,491,000	640,000	325,000	814,000	1,740,000	1,143,000	766,000	3,255,000		4,463,000		4,231,000
Net Income (Loss) After Dividends on Preferred and Preference Stock	414,000	852,000	297,000	81,000	383,000	976,000	623,000	368,000	1,644,000	[1],[2]	2,350,000	[1]	2,203,000	[1]
Basic Earnings, Per Common Share	$ 0.47	$ 0.97	$ 0.34	$ 0.09	$ 0.44	$ 1.11	$ 0.71	$ 0.42	$ 1.88		$ 2.70		$ 2.57
Diluted Earnings, Per Common Share	$ 0.47	$ 0.97	$ 0.34	$ 0.09	$ 0.44	$ 1.11	$ 0.71	$ 0.42	$ 1.87		$ 2.67		$ 2.55
Dividends, Per Common Share	$ 0.5075	$ 0.5075	$ 0.5075	$ 0.4900	$ 0.49	$ 0.49	$ 0.49	$ 0.4725
Trading Price Range, High, Per Common Share	$ 42.94	$ 45.75	$ 48.74	$ 46.95	$ 47.09	$ 48.59	$ 48.45	$ 46.06
Trading Price Range, Low, Per Common Share	$ 40.03	$ 40.63	$ 42.32	$ 42.82	$ 41.75	$ 44.64	$ 44.22	$ 43.71
Southern Power [Member]
Summarized quarterly financial information
Operating revenues	300,257	364,767	307,255	302,947	291,591	354,971	285,805	253,681	1,275,226		1,186,048		1,235,961
Operating Income (Loss)	53,781	116,497	55,024	64,673	65,816	119,234	90,038	56,343	289,975		331,431		336,451
Net Income (Loss) After Dividends on Preferred and Preference Stock	23,266	85,153	27,922	29,192	30,991	68,376	46,602	29,316
Mississippi Power [Member]
Summarized quarterly financial information
Operating revenues	267,582	325,206	306,435	245,934	235,779	305,419	266,084	228,714	1,145,157		1,035,996		1,112,877
Operating Income (Loss)	(24,412)	(79,890)	(388,395)	(429,148)	(46,338)	66,151	46,986	30,213	(921,845)		97,012		133,790
Net Income (Loss) After Dividends on Preferred and Preference Stock	12,921	(24,115)	(219,110)	(246,321)	(14,965)	54,625	35,027	25,255	(476,625)		99,942		94,182
Alabama Power [Member]
Summarized quarterly financial information
Operating revenues	1,314,000	1,604,000	1,392,000	1,308,000	1,290,000	1,637,000	1,377,000	1,216,000	5,618,000		5,520,000		5,702,000
Operating Income (Loss)	312,000	500,000	357,000	307,000	271,000	544,000	390,000	291,000	1,476,000		1,496,000		1,514,000
Net Income (Loss) After Dividends on Preferred and Preference Stock	140,000	258,000	173,000	141,000	113,000	280,000	185,000	126,000	712,000		704,000		708,000
Georgia Power [Member]
Summarized quarterly financial information
Operating revenues	1,866,000	2,484,000	2,042,000	1,882,000	1,735,000	2,498,000	2,020,000	1,745,000	8,274,000		7,998,000		8,800,000
Operating Income (Loss)	404,000	872,000	552,000	412,000	400,000	924,000	535,000	344,000	2,240,000		2,203,000		2,047,000
Net Income (Loss) After Dividends on Preferred and Preference Stock	208,000	487,000	282,000	197,000	181,000	525,000	295,000	167,000	1,174,000		1,168,000		1,145,000
Gulf Power [Member]
Summarized quarterly financial information
Operating revenues	343,493	399,361	371,173	326,274	331,490	421,819	370,208	316,245	1,440,301		1,439,762		1,519,812
Operating Income (Loss)	56,436	87,776	69,151	51,640	53,818	93,813	71,465	49,098	265,003		268,194		224,724
Net Income (Loss) After Dividends on Preferred and Preference Stock	$ 25,301	$ 44,754	$ 32,582	$ 21,792	$ 22,549	$ 47,754	$ 34,963	$ 20,666	$ 124,429		$ 125,932		$ 105,005

[1] (a) After dividends on preferred and preference stock of subsidiaries.

[2] (b) Segment net income (loss) in 2013 includes $1.2 billion in pre-tax charges ($729 million after tax) for estimated probable losses on the Kemper IGCC. See Note (3) under "Integrated Coal Gasification Combined Cycle – Kemper IGCC Construction Schedule and Cost Estimate" for additional information.