Financing - Scheduled Maturities and Redemptions of Securities Due Within One Year (Details) (USD $)									12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2012 Alabama Power [Member]	Dec. 31, 2011 Alabama Power [Member]	Dec. 31, 2012 Georgia Power [Member]	Dec. 31, 2011 Georgia Power [Member]	Dec. 31, 2012 Mississippi Power [Member]	Dec. 31, 2011 Mississippi Power [Member]	Dec. 31, 2012 4.92% Redeemable Preferred Stock [Member] Alabama Power [Member]		Dec. 31, 2012 4.72% Redeemable Preferred Stock [Member] Alabama Power [Member]		Dec. 31, 2012 4.64% Redeemable Preferred Stock [Member] Alabama Power [Member]		Dec. 31, 2012 4.60% Redeemable Preferred Stock [Member] Alabama Power [Member]		Dec. 31, 2012 4.52% Redeemable Preferred Stock [Member] Alabama Power [Member]		Dec. 31, 2012 4.20% Redeemable Preferred Stock [Member] Alabama Power [Member]		Dec. 31, 2012 5.83% Class A Preferred Stock [Member] Alabama Power [Member]	Dec. 31, 2012 5.20% Class A Preferred Stock [Member] Alabama Power [Member]	Dec. 31, 2012 5.30% Class A Preferred Stock [Member] Alabama Power [Member]	Dec. 31, 2012 5.625% Preference Stock [Member] Alabama Power [Member]	Dec. 31, 2012 6.450% Preference Stock [Member] Alabama Power [Member]		Dec. 31, 2012 6.500% Preference Stock [Member] Alabama Power [Member]
Redeemable Preferred/Preference Stock [Abstract]
Redeemable Preferred Stock/Preference Stock dividend rate percentage									0.0492		0.0472		0.0464		0.0460		0.0452		0.0420		0.0583	0.0520	0.0530	0.05625	0.06450		0.06500
Par Value/Stated Capital Per Share									$ 100		$ 100		$ 100		$ 100		$ 100		$ 100		$ 25	$ 25	$ 25	$ 25	$ 25		$ 25
Temporary Equity, Shares Outstanding							334,210	334,210	80,000	[1]	50,000	[1]	60,000	[1]	100,000	[1]	50,000	[1]	135,115	[1]	1,520,000	6,480,000	4,000,000	6,000,000	6,000,000	[1],[2]	2,000,000	[1],[2]
Redemption Price Per Share									$ 103.23		$ 102.18		$ 103.14		$ 104.20		$ 102.93		$ 105.00
Scheduled maturities and redemptions of securities due within one year
Pollution control revenue bonds							$ 51,500,000	$ 0
Capitalized leases	23,000,000	24,000,000			5,000,000	5,000,000	0	600,000
Bank term loans					0	250,000,000	175,000,000	240,000,000
Senior notes	2,085,000,000	1,200,000,000	250,000,000	500,000,000	1,675,000,000	200,000,000	50,000,000	0
Other long-term debt	227,000,000	493,000,000
Total	$ 2,335,000,000	$ 1,717,000,000	$ 250,000,000	$ 500,000,000	$ 1,680,000,000	$ 455,000,000	$ 276,471,000	$ 240,633,000

[1] *Redemption permitted any time after issuance

[2] **Prior to 10/01/2017: Stated Value Plus Make-Whole Premium; after 10/01/2017: Stated Capital