Derivatives (Details 1) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	$ 36
Liability Derivatives	224
Energy-related derivatives [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(164)
Energy-related derivatives [Member] | Other regulatory assets, current [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(123)
Energy-related derivatives [Member] | Other regulatory assets, deferred [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(64)
Energy-related derivatives [Member] | Other regulatory liabilities, current [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	14
Energy-related derivatives [Member] | Other regulatory liabilities, deferred [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	9
Alabama Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	3
Liability Derivatives	63
Alabama Power [Member] | Energy-related derivatives [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(32)
Alabama Power [Member] | Energy-related derivatives [Member] | Other regulatory assets, current [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(26)
Alabama Power [Member] | Energy-related derivatives [Member] | Other regulatory assets, deferred [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(9)
Alabama Power [Member] | Energy-related derivatives [Member] | Other regulatory liabilities, current [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	1
Alabama Power [Member] | Energy-related derivatives [Member] | Other regulatory liabilities, deferred [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	2
Georgia Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	17
Liability Derivatives	75
Georgia Power [Member] | Energy-related derivatives [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(58)
Georgia Power [Member] | Energy-related derivatives [Member] | Other deferred credits and liabilities [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	4
Georgia Power [Member] | Energy-related derivatives [Member] | Other regulatory assets, current [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(52)
Georgia Power [Member] | Energy-related derivatives [Member] | Other regulatory assets, deferred [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(23)
Georgia Power [Member] | Energy-related derivatives [Member] | Other regulatory liabilities, current [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	13
Gulf Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	2
Liability Derivatives	39
Gulf Power [Member] | Energy-related derivatives [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(37)
Gulf Power [Member] | Energy-related derivatives [Member] | Other regulatory assets, current [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(20)
Gulf Power [Member] | Energy-related derivatives [Member] | Other regulatory assets, deferred [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(19)
Gulf Power [Member] | Energy-related derivatives [Member] | Other regulatory liabilities, deferred [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	2
Mississippi Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	1
Liability Derivatives	40
Mississippi Power [Member] | Energy-related derivatives [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(37)
Mississippi Power [Member] | Energy-related derivatives [Member] | Other regulatory assets, current [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(25)
Mississippi Power [Member] | Energy-related derivatives [Member] | Other regulatory assets, deferred [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	(13)
Mississippi Power [Member] | Energy-related derivatives [Member] | Other regulatory liabilities, deferred [Member]
Pre-tax effect of unrealized derivative gains (losses)
Regulatory hedge unrealized gain (loss) recognized on balance sheet	1
Southern Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	1
Liability Derivatives	7
Cash Flow and Fair Value Hedging [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	12
Liability Derivatives	30
Cash Flow and Fair Value Hedging [Member] | Energy-related derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	1
Cash Flow and Fair Value Hedging [Member] | Interest rate derivatives [Member] | Other Current Assets [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	6
Cash Flow and Fair Value Hedging [Member] | Interest rate derivatives [Member] | Other deferred charges and assets [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	6
Cash Flow and Fair Value Hedging [Member] | Interest rate derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	28
Cash Flow and Fair Value Hedging [Member] | Foreign currency derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	1
Cash Flow and Fair Value Hedging [Member] | Alabama Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	28
Cash Flow and Fair Value Hedging [Member] | Alabama Power [Member] | Interest rate derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	28
Cash Flow and Fair Value Hedging [Member] | Mississippi Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	1
Cash Flow and Fair Value Hedging [Member] | Mississippi Power [Member] | Foreign currency derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	1
Cash Flow and Fair Value Hedging [Member] | Southern Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	1
Cash Flow and Fair Value Hedging [Member] | Southern Power [Member] | Energy-related derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	1
Hedging Instruments for Regulatory Purposes [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	23
Liability Derivatives	187
Hedging Instruments for Regulatory Purposes [Member] | Energy-related derivatives [Member] | Other Current Assets [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	14
Hedging Instruments for Regulatory Purposes [Member] | Energy-related derivatives [Member] | Other deferred charges and assets [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	9
Hedging Instruments for Regulatory Purposes [Member] | Energy-related derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	123
Hedging Instruments for Regulatory Purposes [Member] | Energy-related derivatives [Member] | Other deferred credits and liabilities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	64
Hedging Instruments for Regulatory Purposes [Member] | Alabama Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	3
Liability Derivatives	35
Hedging Instruments for Regulatory Purposes [Member] | Alabama Power [Member] | Energy-related derivatives [Member] | Other Current Assets [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	1
Hedging Instruments for Regulatory Purposes [Member] | Alabama Power [Member] | Energy-related derivatives [Member] | Other deferred charges and assets [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	2
Hedging Instruments for Regulatory Purposes [Member] | Alabama Power [Member] | Energy-related derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	26
Hedging Instruments for Regulatory Purposes [Member] | Alabama Power [Member] | Energy-related derivatives [Member] | Other deferred credits and liabilities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	9
Hedging Instruments for Regulatory Purposes [Member] | Georgia Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	17
Liability Derivatives	75
Hedging Instruments for Regulatory Purposes [Member] | Georgia Power [Member] | Energy-related derivatives [Member] | Other Current Assets [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	13
Hedging Instruments for Regulatory Purposes [Member] | Georgia Power [Member] | Energy-related derivatives [Member] | Other deferred charges and assets [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	4
Hedging Instruments for Regulatory Purposes [Member] | Georgia Power [Member] | Energy-related derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	52
Hedging Instruments for Regulatory Purposes [Member] | Georgia Power [Member] | Energy-related derivatives [Member] | Other deferred credits and liabilities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	23
Hedging Instruments for Regulatory Purposes [Member] | Gulf Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	2
Liability Derivatives	39
Hedging Instruments for Regulatory Purposes [Member] | Gulf Power [Member] | Energy-related derivatives [Member] | Other deferred charges and assets [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	2
Hedging Instruments for Regulatory Purposes [Member] | Gulf Power [Member] | Energy-related derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	20
Hedging Instruments for Regulatory Purposes [Member] | Gulf Power [Member] | Energy-related derivatives [Member] | Other deferred credits and liabilities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	19
Hedging Instruments for Regulatory Purposes [Member] | Mississippi Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	1
Liability Derivatives	38
Hedging Instruments for Regulatory Purposes [Member] | Mississippi Power [Member] | Energy-related derivatives [Member] | Other deferred charges and assets [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	1
Hedging Instruments for Regulatory Purposes [Member] | Mississippi Power [Member] | Energy-related derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	25
Hedging Instruments for Regulatory Purposes [Member] | Mississippi Power [Member] | Energy-related derivatives [Member] | Other deferred credits and liabilities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	13
Not Designated as Hedging Instrument [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	7
Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Other deferred charges and assets [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	1
Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	6
Not Designated as Hedging Instrument [Member] | Foreign currency derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	1
Not Designated as Hedging Instrument [Member] | Mississippi Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	1
Not Designated as Hedging Instrument [Member] | Mississippi Power [Member] | Foreign currency derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	1
Not Designated as Hedging Instrument [Member] | Southern Power [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	6
Not Designated as Hedging Instrument [Member] | Southern Power [Member] | Energy-related derivatives [Member] | Other deferred charges and assets [Member]
Fair value of energy-related derivatives and interest rate derivatives
Asset Derivatives	1
Not Designated as Hedging Instrument [Member] | Southern Power [Member] | Energy-related derivatives [Member] | Liabilities from risk management activities [Member]
Fair value of energy-related derivatives and interest rate derivatives
Liability Derivatives	$ 6