Accounting For Certain Long-Lived Assets (Details) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2016 |
Dec. 31, 2015 |
Dec. 31, 2014 |
|
| Schedule of Impaired Long-Lived Assets Held and Used [Line Items] | |||
| Proved oil and gas properties, other property, plant and equipment and other assets carrying amount | $ 667 | $ 9,154 | |
| Amortization and impairments of unproved oil and gas property costs including amortization of capitalized interest | 291 | 288 | $ 168 |
| Proved oil and gas properties, other property, plant and equipment, and other assets written down to fair value | 537 | 2,828 | |
| Pretax impairment charges for proved oil and gas properties, other property, plant and equipment and other assets | $ 130 | 6,326 | |
| Net of tax impairment charges for proved oil and gas properties, other property, plant and equipment and other assets | $ 4,141 | ||