|**Asset Impairments (Tables)**                                                       | 6 Months Ended                                                                                                                                                                                                                                                                                           
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|**Asset Impairments [Abstract]**                                                     |                                                                                                                                                                                                                                                                                                          
|Details of Impairment of Long-Lived Assets Held and Used by Asset [Table Text Block] | Pre-tax (non-cash) asset impairment charges were as follows:Three Months EndedJune 30,Six Months Ended June 30,(millions)2014201320142013US Properties, Primarily Shelf and Deepwater Gulf of Mexico$18$—$23$—Mari-B (Offshore Israel)14—14—McCulloch and Other North Sea Properties2—94—Total$34$—$131$—
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|                                                                                     | Three Months EndedJune 30,                                                                                                                                                                                                                                                                               
|(millions)                                                                           | 2014                                                                                                                                                                                                                                                                                                     
|US Properties, Primarily Shelf and Deepwater Gulf of Mexico                          | $                                                                                                                                                                                                                                                                                                        
|Mari-B (Offshore Israel)                                                             | 14                                                                                                                                                                                                                                                                                                       
|McCulloch and Other North Sea Properties                                             | 2                                                                                                                                                                                                                                                                                                        
|Total                                                                                | $                                                                                                                                                                                                                                                                                                        

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                    duration X- DefinitionTabular disclosure for impairment of long-lived assets held and used by an entity which includes a description of the impaired long-lived asset and facts and circumstances leading to the impairment, aggregate amount of the impairment loss and where the loss is located in the income statement, method(s) for determining fair value, and the segment in which the impaired long-lived asset is reported.+ ReferencesReference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Staff Accounting Bulletin (SAB) -Number Topic 5 -Section CC -Subsection 3Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6391110&loc=d3e2921-110230+ Details**Name:**
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