Derivatives (Details Textual) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2012
Derivatives (Textual) [Abstract]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints		8,000,000
Maximum potential collateral requirements arising the from credit-risk-related contingent features	$ 27	$ 27
Energy-related derivatives [Member]
Derivatives (Textual) [Abstract]
Pre-tax gains from energy-related derivatives not designated as hedging instruments on the statements of income	10	4
Alabama Power [Member]
Derivatives (Textual) [Abstract]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints		1,000,000
Maximum potential collateral requirements arising the from credit-risk-related contingent features	27	27
Georgia Power [Member]
Derivatives (Textual) [Abstract]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints		3,000,000
Maximum potential collateral requirements arising the from credit-risk-related contingent features	27	27
Gulf Power [Member]
Derivatives (Textual) [Abstract]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints		1,000,000
Maximum potential collateral requirements arising the from credit-risk-related contingent features	27	27
Mississippi Power [Member]
Derivatives (Textual) [Abstract]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints		1,000,000
Maximum potential collateral requirements arising the from credit-risk-related contingent features	27	27
Southern Power [Member]
Derivatives (Textual) [Abstract]
Expected volume of natural gas subject to option to sell back excess gas due to operational constraints		2,000,000
Maximum potential collateral requirements arising the from credit-risk-related contingent features	$ 27	$ 27