| **Asset Retirement Obligations (Details) - USD ($) $ in Millions**                                       | 6 Months Ended |
|----------------------------------------------------------------------------------------------------------|----------------|
||
| **Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]**                                    |                |   |   |
| Asset Retirement Obligations, Beginning Balance                                                          |                | $ 751 | $ 586 |
| Liabilities Incurred                                                                                     |                | 16 | 22 |
| Liabilities Settled                                                                                      |                | (15) | (43) |
| Revision of Estimate                                                                                     |                | 79 | 120 |
| Accretion Expense                                                                                        | [1]            | (21) | (19) |
| Asset Retirement Obligations, Ending Balance                                                             |                | 852 | 704 |
| Onshore US [Member]                                                                                      |                |   |   |
| **Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]**                                    |                |   |   |
| Revision of Estimate                                                                                     |                | 28 | 21 |
| Eastern Mediterranean [Member]                                                                           |                |   |   |
| **Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]**                                    |                |   |   |
| Revision of Estimate                                                                                     |                | $ 43 | 9 |
| Deepwater Gulf of Mexico [Member]                                                                        |                |   |   |
| **Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]**                                    |                |   |   |
| Revision of Estimate                                                                                     |                |   | 7 |
| North Sea [Member]                                                                                       |                |   |   |
| **Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]**                                    |                |   |   |
| Revision of Estimate                                                                                     |                |   | 67 |
| Equatorial Guinea                                                                                        |                |   |   |
| **Asset Retirement Obligation, Roll Forward Analysis [Roll Forward]**                                    |                |   |   |
| Revision of Estimate                                                                                     |                |   | $ 16 |
|                                                                                                          |
| [1]Accretion expense is included in DD&A expense in the consolidated statements of operations. |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
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| - Definition
The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.
+ References
Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Asset Retirement Obligation -URI http://asc.fasb.org/extlink&oid=6505190
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of accretion expense recognized during the period that is associated with an asset retirement obligation. Accretion expense measures and incorporates changes due to the passage of time into the carrying amount of the liability.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                    |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of asset retirement obligations incurred during the period.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                       |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of asset retirement obligations settled, or otherwise disposed of, during the period. This may include asset retirement obligations transferred to third parties associated with the sale of a long-lived asset.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of the Increase or Decrease in the amount of the asset retirement obligation during the current period for changes in the amount or timing of the estimated cash flows associated with the settlement of the obligation.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.
+ References
No definition available.
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