|**Fair Value Measurements and Disclosures (Details 3) (USD $)In Millions, unless otherwise specified**                                                 | Jun. 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                                                                                                             | $ 4,121                                                                                                                              | [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                                                                                                             | $ 4,712                                                                                                                              | [1]                                                                                                                                 
|                                                                                                                                                      
|[1]
              Excludes Aseng FPSO lease obligation. No floating rate debt was outstanding at June 30, 2012 or December 31, 2011. See Note 5. Debt. | [1]                                                                                                                                  | Excludes Aseng FPSO lease obligation. No floating rate debt was outstanding at June 30, 2012 or December 31, 2011. See Note 5. Debt.
|[1]                                                                                                                                                    | Excludes Aseng FPSO lease obligation. No floating rate debt was outstanding at June 30, 2012 or December 31, 2011. See Note 5. Debt.

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