Derivatives (Details) In Millions, unless otherwise specified	6 Months Ended		6 Months Ended		6 Months Ended								6 Months Ended
	Jun. 30, 2012 USD ($)	Jun. 30, 2012 Fair Value Hedging [Member] USD ($)	Jun. 30, 2012 Alabama Power [Member] USD ($)	Jun. 30, 2012 Alabama Power [Member] Cash Flow Hedging [Member] USD ($)	Jun. 30, 2012 Georgia Power [Member] USD ($)	Jun. 30, 2012 Gulf Power [Member] USD ($)	Jun. 30, 2012 Mississippi Power [Member] USD ($)	Jun. 30, 2012 Mississippi Power [Member] EUR (€)	Jun. 30, 2012 Mississippi Power [Member] Derivatives not designated as hedges [Member] USD ($)	Jun. 30, 2012 Mississippi Power [Member] Derivatives not designated as hedges [Member] EUR (€)	Jun. 30, 2012 Mississippi Power [Member] Fair Value Hedging [Member] USD ($)	Jun. 30, 2012 Mississippi Power [Member] Fair Value Hedging [Member] EUR (€)	Jun. 30, 2012 Southern Power [Member] USD ($)	Jun. 30, 2012 Gas [Member] MMBTU	Jun. 30, 2012 Gas [Member] Alabama Power [Member] MMBTU	Jun. 30, 2012 Gas [Member] Georgia Power [Member] MMBTU	Jun. 30, 2012 Gas [Member] Gulf Power [Member] MMBTU	Jun. 30, 2012 Gas [Member] Mississippi Power [Member] MMBTU	Jun. 30, 2012 Gas [Member] Southern Power [Member] MMBTU
Energy-related derivative contracts
Net Purchased mmBtu														242,000,000	43,000,000	96,000,000	51,000,000	34,000,000	18,000,000
Longest Hedge Date														2017	2017	2017	2017	2017	2012
Longest Non-Hedge Date														2017					2017
Notional amount of interest rate derivatives
Notional Amount			$ 300
Notional Amount, Fair Value	350
Notional Amount of interest rate derivatives, Total	650
Interest Rate Received		0.0415		3-month LIBOR
Interest Rate Paid		3-month LIBOR + 1.96%		0.0290
Hedge Maturity Date		May 01, 2014		Dec. 01, 2022
Fair Value Gain (Loss) June 30, 2012	(16)	12		(28)
Total deferred gains and losses are expected to be amortized into earnings
Estimated Gain (Loss) to be Reclassified for the 12 Months Ending June 30, 2013	(17)		(1)		(3)	(1)	(1)						(11)
Total Deferred Gains (Losses) Amortized Through	2037		2035		2037	2020	2022	2022					2016
Notional amount of outstanding foreign currency derivatives
Notional Amount								24.4		18.1		6.3
Forward Rate									1.3186		1.3850
Hedge maturity date											Various through March 2014	Various through March 2014
Fair Value Gain (Loss) June 30, 2012							$ (2)		$ (1)		$ (1)