XML 66 R49.htm IDEA: XBRL DOCUMENT v2.4.0.6
Derivatives And Other Financial Instruments (Schedule Of Derivative Contract Assets And Liabilities That Are Measured And Recognized At Fair Value On A Recurring Basis) (Details) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2012
Dec. 31, 2011
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Fair value asset derivatives $ 81 $ 94
Fair value liability derivatives 781 737
Level 1 [Member]
   
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Fair value asset derivatives 46 57
Fair value liability derivatives 22 64
Level 2 [Member]
   
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Fair value asset derivatives 45 47
Fair value liability derivatives 47 44
Level 3 [Member]
   
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Fair value asset derivatives 8 12
Fair value liability derivatives 712 630
Margin Held [Member]
   
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Margin held (18) (22)
Margin Posted [Member]
   
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]    
Margin posted   $ (1)