v2.4.0.6
Fair Value Measurements (Schedule Of Carrying Value And Fair Value Measurement Information For Financial Assets And Liabilities) (Details) (USD $)
In Millions, unless otherwise specified
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Investments $ 84 $ 94  
Derivatives, assets 680 389  
Derivatives, liabilities (82) (192)  
Carrying Amount [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Debt (9,780) (5,630)  
Cash equivalents 5,123 2,335  
Total Fair Value [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Debt (11,380) (6,629)  
Cash equivalents 5,123 2,335  
Level 1 Inputs [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Cash equivalents 1,369 2,335  
Level 2 Inputs [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Debt (11,295) (6,485)  
Cash equivalents 3,754    
Level 3 Inputs [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Debt (85) (144)  
Short-Term Investments [Member] | Carrying Amount [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Investments 1,503 145  
Short-Term Investments [Member] | Total Fair Value [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Investments 1,503 145  
Short-Term Investments [Member] | Level 1 Inputs [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Investments 490 145  
Short-Term Investments [Member] | Level 2 Inputs [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Investments 1,013    
Long-Term Investments [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Investments 84 94 115
Long-Term Investments [Member] | Carrying Amount [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Investments 84 94  
Long-Term Investments [Member] | Total Fair Value [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Investments 84 94  
Long-Term Investments [Member] | Level 3 Inputs [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Investments 84 94  
Commodity Derivatives [Member] | Carrying Amount [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Derivatives, assets 628 249  
Derivatives, liabilities (82) (192)  
Commodity Derivatives [Member] | Total Fair Value [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Derivatives, assets 628 249  
Derivatives, liabilities (82) (192)  
Commodity Derivatives [Member] | Level 2 Inputs [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Derivatives, assets 628 249  
Derivatives, liabilities (82) (192)  
Interest Rate Derivatives [Member] | Carrying Amount [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Derivatives, assets 52 140  
Interest Rate Derivatives [Member] | Total Fair Value [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Derivatives, assets 52 140  
Interest Rate Derivatives [Member] | Level 2 Inputs [Member]
      
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]      
Derivatives, assets $ 52 $ 140