| **Divestitures (Details) (USD $)In Millions, unless otherwise specified**                                                                                                             | 3 Months Ended | 6 Months Ended |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|----------------|----------------|
||
| **Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]**                                                     |           |           |   |  |   |
| Sales Proceeds                                                                                                                                                                        |           |           | $ 146 |  | $ 114 |
| Asset Retirement Obligations Associated with Assets Sold                                                                                                                              |           |           | 43 |  | 10 |
| Gain on Divestitures                                                                                                                                                                  | 44             | (4)            | 42 |  | 12 |
| US Onshore Assets Sold [Member]                                                                                                                                                       |           |           |   |  |   |
| **Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]**                                                     |           |           |   |  |   |
| Sales Proceeds                                                                                                                                                                        | 18             |           | 110 |  |   |
| Net Book Value of Assets Sold                                                                                                                                                         | (11)           |           | (118) |  |   |
| Goodwill Allocated to Assets Sold                                                                                                                                                     | 0              |           | (6) |  |   |
| Asset Retirement Obligations Associated with Assets Sold                                                                                                                              | 0              |           | 20 |  |   |
| Gain on Divestitures                                                                                                                                                                  | 7              |           | 6 |  |   |
| China Assets Sold [Member]                                                                                                                                                            |           |           |   |  |   |
| **Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]**                                                     |           |           |   |  |   |
| Sales Proceeds                                                                                                                                                                        |           |           | 36 |  |   |
| Noncash Consideration Received                                                                                                                                                        |           |           | 150 |  |   |
| Consideration Received                                                                                                                                                                |           |           | 186 | [1] |   |
| Net Book Value of Assets Sold                                                                                                                                                         |           |           | 149 |  |   |
| Other Closing Adjustments                                                                                                                                                             |           |           | 2 |  |   |
| Gain on Divestitures                                                                                                                                                                  |           |           | $ 35 |  |   |
|                                                                                                                                                                                       |
| [1](1) Proceeds included $36 million cash received prior to June 30, 2014 and $150 million cash received on July 2, 2014, which was recorded as accounts receivable at June 30, 2014. |

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Write-off of the carrying amount (book value) associated with assets sold in the period.
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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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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
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| - Definition
Amount of gain (loss) on sale or disposal of proven and unproven oil and gas properties.
+ References
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
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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| - Definition
Amount of noncash consideration received for selling an asset or business through a noncash (or part noncash) transaction.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
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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