|**Capitalized Exploratory Well Costs (Details) (USD $)In Millions, unless otherwise specified**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       | 12 Months Ended                                                                                                                                                                                                                                                                                                                                  
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
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|**Capitalized Exploratory Well Costs [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                  
|Capitalized Exploratory Well Costs, Beginning of Period                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | $ 696                                                                                                                                                                                                                                                                                                                                            
|Additions to Capitalized Exploratory Well Costs Pending Determination of Proved Reserves                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              | 360                                                                                                                                                                                                                                                                                                                                              
|Reclassified to Proved Oil and Gas Properties Based on Determination of Proved Reserves                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               | (18)                                                                                                                                                                                                                                                                                                                                             
|Capitalized Exploratory Well Costs Charged to Expense (1)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | (114)                                                                                                                                                                                                                                                                                                                                            
|Other (2)                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             | (24)                                                                                                                                                                                                                                                                                                                                             
|Capitalized Exploratory Well Costs, End of Period                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     | 900                                                                                                                                                                                                                                                                                                                                              
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 271                                                                                                                                                                                                                                                                                                                                              
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 55                                                                                                                                                                                                                                                                                                                                               
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 219                                                                                                                                                                                                                                                                                                                                              
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 545                                                                                                                                                                                                                                                                                                                                              
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period of One Year or Less                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | 355                                                                                                                                                                                                                                                                                                                                              
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 545                                                                                                                                                                                                                                                                                                                                              
|Capitalized Exploratory Well Costs,                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | 900                                                                                                                                                                                                                                                                                                                                              
|Number of Projects with Exploratory Well Costs That Have Been Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           | 14                                                                                                                                                                                                                                                                                                                                               
|Carla Offshore Equatorial Guinea                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 12                                                                                                                                                                                                                                                                                                                                               
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 0                                                                                                                                                                                                                                                                                                                                                
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 0                                                                                                                                                                                                                                                                                                                                                
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 12                                                                                                                                                                                                                                                                                                                                               
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 12                                                                                                                                                                                                                                                                                                                                               
|Carmen Offshore Equatorial Guinea                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 1                                                                                                                                                                                                                                                                                                                                                
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 1                                                                                                                                                                                                                                                                                                                                                
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 20                                                                                                                                                                                                                                                                                                                                               
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 22                                                                                                                                                                                                                                                                                                                                               
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 22                                                                                                                                                                                                                                                                                                                                               
|Diega Offshore Equatorial Guinea                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 45                                                                                                                                                                                                                                                                                                                                               
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 2                                                                                                                                                                                                                                                                                                                                                
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 35                                                                                                                                                                                                                                                                                                                                               
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 82                                                                                                                                                                                                                                                                                                                                               
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 82                                                                                                                                                                                                                                                                                                                                               
|Felicita Offshore Equatorial Guinea                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 2                                                                                                                                                                                                                                                                                                                                                
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 2                                                                                                                                                                                                                                                                                                                                                
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 31                                                                                                                                                                                                                                                                                                                                               
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 35                                                                                                                                                                                                                                                                                                                                               
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 35                                                                                                                                                                                                                                                                                                                                               
|Yolanda Offshore Equatorial Guinea                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 1                                                                                                                                                                                                                                                                                                                                                
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 1                                                                                                                                                                                                                                                                                                                                                
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 16                                                                                                                                                                                                                                                                                                                                               
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 18                                                                                                                                                                                                                                                                                                                                               
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 18                                                                                                                                                                                                                                                                                                                                               
|YoYo Offshore Cameron                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 5                                                                                                                                                                                                                                                                                                                                                
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 2                                                                                                                                                                                                                                                                                                                                                
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 38                                                                                                                                                                                                                                                                                                                                               
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 45                                                                                                                                                                                                                                                                                                                                               
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 45                                                                                                                                                                                                                                                                                                                                               
|Leviathan Offshore Israel                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 67                                                                                                                                                                                                                                                                                                                                               
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 41                                                                                                                                                                                                                                                                                                                                               
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 0                                                                                                                                                                                                                                                                                                                                                
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 108                                                                                                                                                                                                                                                                                                                                              
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 108                                                                                                                                                                                                                                                                                                                                              
|Leviathan-1 Deep Offshore Israel                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 28                                                                                                                                                                                                                                                                                                                                               
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 0                                                                                                                                                                                                                                                                                                                                                
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 0                                                                                                                                                                                                                                                                                                                                                
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 28                                                                                                                                                                                                                                                                                                                                               
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 28                                                                                                                                                                                                                                                                                                                                               
|Tanin 1 Offshore Israel                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 31                                                                                                                                                                                                                                                                                                                                               
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 0                                                                                                                                                                                                                                                                                                                                                
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 0                                                                                                                                                                                                                                                                                                                                                
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 31                                                                                                                                                                                                                                                                                                                                               
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 31                                                                                                                                                                                                                                                                                                                                               
|Dolphin 1 Offshore Israel                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 22                                                                                                                                                                                                                                                                                                                                               
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 0                                                                                                                                                                                                                                                                                                                                                
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 0                                                                                                                                                                                                                                                                                                                                                
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 22                                                                                                                                                                                                                                                                                                                                               
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 22                                                                                                                                                                                                                                                                                                                                               
|Dalit Offshore Israel                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 0                                                                                                                                                                                                                                                                                                                                                
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 1                                                                                                                                                                                                                                                                                                                                                
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 21                                                                                                                                                                                                                                                                                                                                               
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 22                                                                                                                                                                                                                                                                                                                                               
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 22                                                                                                                                                                                                                                                                                                                                               
|Cyprus A-1 Offshore Cyprus                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 57                                                                                                                                                                                                                                                                                                                                               
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 0                                                                                                                                                                                                                                                                                                                                                
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 0                                                                                                                                                                                                                                                                                                                                                
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 57                                                                                                                                                                                                                                                                                                                                               
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 57                                                                                                                                                                                                                                                                                                                                               
|Gunflint Deepwater Gulf Of Mexico                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 0                                                                                                                                                                                                                                                                                                                                                
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 0                                                                                                                                                                                                                                                                                                                                                
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 54                                                                                                                                                                                                                                                                                                                                               
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 54                                                                                                                                                                                                                                                                                                                                               
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 54                                                                                                                                                                                                                                                                                                                                               
|Projects of $10 million or less each                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |                                                                                                                                                                                                                                                                                                                                                  
|**Projects with Exploratory Well Costs Capitalized for More than One Year Since The Commencement of Drilling [Line Items]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           |                                                                                                                                                                                                                                                                                                                                                  
|2011                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 0                                                                                                                                                                                                                                                                                                                                                
|2010                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 5                                                                                                                                                                                                                                                                                                                                                
|2009 & Prior                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          | 4                                                                                                                                                                                                                                                                                                                                                
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | 9                                                                                                                                                                                                                                                                                                                                                
|**Capitalized Exploratory Well Costs Aging [Abstract]**                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                               |                                                                                                                                                                                                                                                                                                                                                  
|Exploratory Well Costs Capitalized for a Period Greater Than One Year Since Commencement of Drilling                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  | $ 9                                                                                                                                                                                                                                                                                                                                              
|                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     
|[1]
              Amount primarily represents Deep Blue (deepwater Gulf of Mexico) exploratory well costs capitalized prior to December 31, 2012. Although hydrocarbons were found in both the initial exploration well and subsequent sidetrack, we and our partners decided not to proceed with additional appraisal activities.[2]
              Amount relates to Selkirk (North Sea) exploratory well costs capitalized prior to December 31, 2012. During the fourth quarter of 2012, our Selkirk field, which is included in discontinued operations, was determined to be uneconomic for joint development and was charged to exploration expense. See Note 3. Acquisitions and Divestitures. | [1]                                                                                                                                                                                                                                                                                                                                              
|[1]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | Amount primarily represents Deep Blue (deepwater Gulf of Mexico) exploratory well costs capitalized prior to December 31, 2012. Although hydrocarbons were found in both the initial exploration well and subsequent sidetrack, we and our partners decided not to proceed with additional appraisal activities.                                 
|[2]                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   | Amount relates to Selkirk (North Sea) exploratory well costs capitalized prior to December 31, 2012. During the fourth quarter of 2012, our Selkirk field, which is included in discontinued operations, was determined to be uneconomic for joint development and was charged to exploration expense. See Note 3. Acquisitions and Divestitures.

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