| **Divestitures (Details) - USD ($) $ in Millions**                                                                                | 3 Months Ended | 6 Months Ended |
|-----------------------------------------------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]** |                |           |   |   |   |
| Sales Proceeds                                                                                                                    |                |           |   | $ 151 | $ 146 |
| Asset Retirement Obligations Associated with Assets Sold                                                                          |                |           |   | 15 | 43 |
| Gain on Divestitures                                                                                                              |                | $ (1)          | $ (44) | 0 | (42) |
| US Onshore Assets Sold [Member]                                                                                                   |                |           |   |   |   |
| **Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]** |                |           |   |   |   |
| Sales Proceeds                                                                                                                    |                |           |   | $ 151 | 110 |
| Net Book Value of Assets Sold                                                                                                     |                |           |   |   | (118) |
| Goodwill Allocated to Assets Sold                                                                                                 |                |           |   |   | (6) |
| Asset Retirement Obligations Associated with Assets Sold                                                                          |                |           |   |   | 20 |
| Gain on Divestitures                                                                                                              |                |           |   |   | 6 |
| CHINA                                                                                                                             |                |           |   |   |   |
| **Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]** |                |           |   |   |   |
| Other Significant Noncash Transaction, Value of Consideration Given                                                               |                |           |   |   | 150 |
| Sales Proceeds                                                                                                                    | [1]            |           |   |   | 186 |
| Net Book Value of Assets Sold                                                                                                     |                |           |   |   | 149 |
| Other Closing Adjustments                                                                                                         |                |           |   |   | 2 |
| Gain on Divestitures                                                                                                              |                |           |   |   | $ (35) |
|                                                                                                                                   |
| [1]Includes $150 million cash received on July 2, 2014, which was recorded as accounts receivable at June 30, 2014.               |

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| - 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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| - Definition
Amount of gain (loss) on sale or disposal of proven and unproven oil and gas properties.
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Amount of divestiture of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized.
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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.
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The value of the noncash (or part noncash) consideration received in a transaction. Noncash is defined as transactions during a period that do not result in cash receipts or cash payments in the period. "Part noncash" refers to that portion of a transaction not resulting in cash receipts or cash payments in the period.
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| - Definition
The cash inflow to dispose of long-lived, physical assets and mineral interests in oil and gas properties used for normal oil and gas operations.
+ References
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