|**Fair Value Measurements and Disclosures (Details 3) (USD $)In Millions, unless otherwise specified**                                                      | Sep. 30, 2012                                                                                                                             | Dec. 31, 2011                                                                                                                            
|----------------------------------------------------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------- | -----------------------------------------------------------------------------------------------------------------------------------------
|Carrying (Reported) Amount, Fair Value Disclosure                                                                                                           |                                                                                                                                           |                                                                                                                                          
|**Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                           |                                                                                                                                           |                                                                                                                                          
|Long Term Debt Net Of Unamortized Discount                                                                                                                  | $ 3,795                                                                                                                                   | [1]                                                                                                                                      
|Estimate of Fair Value, Fair Value Disclosure                                                                                                               |                                                                                                                                           |                                                                                                                                          
|**Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                                           |                                                                                                                                           |                                                                                                                                          
|Long Term Debt Net Of Unamortized Discount                                                                                                                  | $ 4,500                                                                                                                                   | [1]                                                                                                                                      
|                                                                                                                                                           
|[1]
              Excludes Aseng FPSO lease obligation. No floating rate debt was outstanding at September 30, 2012 or December 31, 2011. See Note 5. Debt. | [1]                                                                                                                                       | Excludes Aseng FPSO lease obligation. No floating rate debt was outstanding at September 30, 2012 or December 31, 2011. See Note 5. Debt.
|[1]                                                                                                                                                         | Excludes Aseng FPSO lease obligation. No floating rate debt was outstanding at September 30, 2012 or December 31, 2011. See Note 5. Debt.

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