| **Asset Impairments (Tables)**              | 12 Months Ended                                                                                                                                                                                                                                                                                                    |
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| **Asset Impairment Charges [Abstract]**     |                                                                                                                                                                                                                                                                                                               |
| Asset Impairment Charges Pre Tax (non-cash) | Pre-tax (non-cash) asset impairment charges were as follows: Year Ended December 31,(millions)2017 2016 2015Gulf of Mexico$63 $— $158Israel— 88 36Equatorial Guinea— — 339Other International7 4 —Total$70 $92 $533 |

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| - References
No definition available.
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| - Definition
Tabular 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.
+ References
Reference 1: 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=84176398&loc=d3e2921-110230Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section S99 -Paragraph 2 -Subparagraph (SAB Topic 5.CC) -URI http://asc.fasb.org/extlink&oid=27011434&loc=d3e125687-122742
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