v2.4.0.6
Property And Equipment (Narrative) (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended 26 Months Ended 12 Months Ended 3 Months Ended 26 Months Ended
Dec. 31, 2011
Dec. 31, 2010
Dec. 31, 2009
Dec. 31, 2011
Dec. 31, 2011
Sinopec International Petroleum Exploration And Production Corporation [Member]
Dec. 31, 2011
Future Drilling Costs [Member]
Sinopec International Petroleum Exploration And Production Corporation [Member]
Dec. 31, 2011
Received At Closing [Member]
Sinopec International Petroleum Exploration And Production Corporation [Member]
Mar. 31, 2009
Gross [Member]
Mar. 31, 2009
After Taxes [Member]
Dec. 31, 2011
After Taxes [Member]
Property, Plant and Equipment [Line Items]                    
Gain on divestiture of operations $ 2,552 $ 1,818 $ 17              
Gain on divestiture of operations, after-tax 2,552 1,732 17              
Reduction of carrying value of oil and gas properties     6,408         6,400 4,100  
Cash Proceeds       10,002           8,000
Payments to acquire interest in joint venture         $ 2,500 $ 1,600 $ 900      
Percentage interest in joint venture 33.30%