|**Fair Value Measurements and Disclosures (Details 2) (USD $)In Millions, unless otherwise specified**                                | Mar. 31, 2013                                                                                                       | Dec. 31, 2012                                                                                                      
|------------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------
|Carrying Amount                                                                                                                       |                                                                                                                     |                                                                                                                    
|**Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                     |                                                                                                                     |                                                                                                                    
|Long Term Debt Net Of Unamortized Discount                                                                                            | $ 3,798                                                                                                             | [1]                                                                                                                
|Fair Value                                                                                                                            |                                                                                                                     |                                                                                                                    
|**Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]**                                                     |                                                                                                                     |                                                                                                                    
|Long Term Debt Net Of Unamortized Discount                                                                                            | $ 4,539                                                                                                             | [1]                                                                                                                
|                                                                                                                                     
|[1]
              Excludes Aseng FPSO lease obligation. No floating rate debt was outstanding at March 31, 2013 or December 31, 2012. | [1]                                                                                                                 | Excludes Aseng FPSO lease obligation. No floating rate debt was outstanding at March 31, 2013 or December 31, 2012.
|[1]                                                                                                                                   | Excludes Aseng FPSO lease obligation. No floating rate debt was outstanding at March 31, 2013 or December 31, 2012.

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