Consolidated Statements of Comprehensive Income (Parenthetical) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Changes in fair value of qualifying hedges, tax	$ (7,000,000)	$ (10,000,000)	$ 0
Reclassification adjustment for amounts of qualifying hedges included in net income, tax	7,000,000	6,000,000	9,000,000
Change in fair value of marketable securities, tax	0	(2,000,000)	(2,000,000)
Benefit plan net gain (loss), tax	(2,000,000)	(1,000,000)	1,000,000
Reclassification adjustment for amounts of pension and other post retirement benefit plans included in net income, tax	(4,000,000)	(14,000,000)	1,000,000
Alabama Power [Member]
Changes in fair value of qualifying hedges, tax	(7,000,000)	(5,000,000)	0
Reclassification adjustment for amounts of qualifying hedges included in net income, tax	1,000,000	(1,000,000)	(1,000,000)
Georgia Power [Member]
Reclassification adjustment for amounts of qualifying hedges included in net income, tax	1,000,000	2,000,000	6,000,000
Gulf Power [Member]
Changes in fair value of qualifying hedges, tax	0	0	(542,000)
Reclassification adjustment for amounts of qualifying hedges included in net income, tax	360,000	360,000	376,000
Mississippi Power [Member]
Changes in fair value of qualifying hedges, tax	(296,000)	(5,494,000)	1,000
Reclassification adjustment for amounts of qualifying hedges included in net income, tax	411,000	(18,000)	0
Southern Power [Member]
Changes in fair value of qualifying hedges, tax	(90,000)	55,000	591,000
Reclassification adjustment for amounts of qualifying hedges included in net income, tax	$ 3,919,000	$ 4,837,000	$ 3,894,000