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Derivatives (Details 1) (USD $)
In Millions
Jun. 30, 2011
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives $ 23
Liability Derivatives 144
Alabama Power [Member] | Cash flow and fair value hedging [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Alabama Power [Member] | 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 0
Alabama Power [Member] | 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 0
Alabama Power [Member] | 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 0
Alabama Power [Member] | Cash flow and fair value hedging [Member] | Foreign Exchange Contract [Member] | Other current assets [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Georgia Power [Member] | Cash flow and fair value hedging [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Georgia Power [Member] | 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 0
Georgia Power [Member] | 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 0
Georgia Power [Member] | 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 0
Georgia Power [Member] | Cash flow and fair value hedging [Member] | Foreign Exchange Contract [Member] | Other current assets [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Gulf Power [Member] | Cash flow and fair value hedging [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Gulf Power [Member] | 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 0
Gulf Power [Member] | 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 0
Gulf Power [Member] | 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 0
Gulf Power [Member] | Cash flow and fair value hedging [Member] | Foreign Exchange Contract [Member] | Other current assets [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Mississippi Power [Member] | Cash flow and fair value hedging [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 4
Mississippi Power [Member] | 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 0
Mississippi Power [Member] | 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 0
Mississippi Power [Member] | 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 0
Mississippi Power [Member] | Cash flow and fair value hedging [Member] | Foreign Exchange Contract [Member] | Other current assets [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 4
Southern Power [Member] | Cash flow and fair value hedging [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Southern Power [Member] | 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 0
Southern Power [Member] | 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 0
Southern Power [Member] | 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 0
Southern Power [Member] | Cash flow and fair value hedging [Member] | Foreign Exchange Contract [Member] | Other current assets [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Cash flow and fair value hedging [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 16
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 1
Cash flow and fair value hedging [Member] | Foreign Exchange Contract [Member] | Other current assets [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 4
Alabama Power [Member] | Hedging instruments for regulatory purposes [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 1
Liability Derivatives 25
Alabama Power [Member] | 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 0
Alabama Power [Member] | 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 1
Alabama Power [Member] | 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 20
Alabama Power [Member] | 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 5
Georgia Power [Member] | Hedging instruments for regulatory purposes [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 1
Liability Derivatives 68
Georgia Power [Member] | 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 0
Georgia Power [Member] | 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 1
Georgia Power [Member] | 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 54
Georgia Power [Member] | 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 14
Gulf Power [Member] | Hedging instruments for regulatory purposes [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 1
Liability Derivatives 10
Gulf Power [Member] | 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 1
Gulf Power [Member] | 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 0
Gulf Power [Member] | 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 6
Gulf Power [Member] | 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 4
Mississippi Power [Member] | Hedging instruments for regulatory purposes [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 1
Liability Derivatives 34
Mississippi Power [Member] | 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 0
Mississippi Power [Member] | 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 1
Mississippi Power [Member] | 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 22
Mississippi Power [Member] | 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 12
Hedging instruments for regulatory purposes [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 4
Liability Derivatives 137
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 1
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 3
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 102
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 35
Alabama Power [Member] | Not Designated as Hedging Instrument [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Liability Derivatives 0
Alabama Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Other current assets [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Alabama Power [Member] | 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 0
Alabama Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Assets from risk management activities [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Alabama Power [Member] | 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 0
Alabama Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Other deferred credits and liabilities [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Liability Derivatives 0
Georgia Power [Member] | Not Designated as Hedging Instrument [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Liability Derivatives 0
Georgia Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Other current assets [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Georgia Power [Member] | 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 0
Georgia Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Assets from risk management activities [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Georgia Power [Member] | 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 0
Georgia Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Other deferred credits and liabilities [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Liability Derivatives 0
Gulf Power [Member] | Not Designated as Hedging Instrument [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Liability Derivatives 0
Gulf Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Other current assets [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Gulf Power [Member] | 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 0
Gulf Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Assets from risk management activities [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Gulf Power [Member] | 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 0
Gulf Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Other deferred credits and liabilities [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Liability Derivatives 0
Mississippi Power [Member] | Not Designated as Hedging Instrument [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Liability Derivatives 0
Mississippi Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Other current assets [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Mississippi Power [Member] | 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 0
Mississippi Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Assets from risk management activities [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Mississippi Power [Member] | 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 0
Mississippi Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Other deferred credits and liabilities [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Liability Derivatives 0
Southern Power [Member] | Not Designated as Hedging Instrument [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 3
Liability Derivatives 6
Southern Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Other current assets [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
Southern Power [Member] | 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
Southern Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Assets from risk management activities [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 2
Southern Power [Member] | 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 5
Southern Power [Member] | Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Other deferred credits and liabilities [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Liability Derivatives 1
Not Designated as Hedging Instrument [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 3
Liability Derivatives 6
Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Other current assets [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 2
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] | Assets from risk management activities [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 0
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 5
Not Designated as Hedging Instrument [Member] | Energy-related derivatives [Member] | Other deferred credits and liabilities [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Liability Derivatives 1
Alabama Power [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 1
Liability Derivatives 25
Alabama Power [Member] | Energy-related derivatives [Member]
 
Pre-tax effect of unrealized derivative gains (losses)  
Regulatory hedge unrealized gain (loss) recognized on balance sheet (24)
Alabama 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 0
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 (20)
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 (5)
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 0
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 1
Georgia Power [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 1
Liability Derivatives 68
Georgia Power [Member] | Energy-related derivatives [Member]
 
Pre-tax effect of unrealized derivative gains (losses)  
Regulatory hedge unrealized gain (loss) recognized on balance sheet (67)
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 1
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 (54)
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 (14)
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 0
Georgia 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 0
Gulf Power [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 1
Liability Derivatives 10
Gulf Power [Member] | Energy-related derivatives [Member]
 
Pre-tax effect of unrealized derivative gains (losses)  
Regulatory hedge unrealized gain (loss) recognized on balance sheet (9)
Gulf 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 0
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 (6)
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 (4)
Gulf 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
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 0
Mississippi Power [Member]
 
Fair value of energy-related derivatives and interest rate derivatives  
Asset Derivatives 5
Liability Derivatives 34
Mississippi Power [Member] | Energy-related derivatives [Member]
 
Pre-tax effect of unrealized derivative gains (losses)  
Regulatory hedge unrealized gain (loss) recognized on balance sheet (33)
Mississippi 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 0
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 (22)
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 (12)
Mississippi 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 0
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 3
Liability Derivatives 6
Energy-related derivatives [Member]
 
Pre-tax effect of unrealized derivative gains (losses)  
Regulatory hedge unrealized gain (loss) recognized on balance sheet (133)
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 0
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 (102)
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 (35)
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
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 $ 3