Segment Disclosures and Related Information - Assets (Details 2) - USD ($) $ in Millions |
Mar. 31, 2017 |
Dec. 31, 2016 |
|---|---|---|
| Assets [Abstract] | ||
| Consolidated total assets | $ 87,973 | $ 89,772 |
| Alaska [Member] | ||
| Assets [Abstract] | ||
| Consolidated total assets | 12,095 | 12,314 |
| Lower 48 [Member] | ||
| Assets [Abstract] | ||
| Consolidated total assets | 21,746 | 22,673 |
| Canada [Member] | ||
| Assets [Abstract] | ||
| Consolidated total assets | 17,707 | 17,548 |
| Europe and North Africa [Member] | ||
| Assets [Abstract] | ||
| Consolidated total assets | 11,562 | 11,727 |
| Asia Pacific and Middle East [Member] | ||
| Assets [Abstract] | ||
| Consolidated total assets | 20,058 | 20,451 |
| Other International [Member] | ||
| Assets [Abstract] | ||
| Consolidated total assets | 99 | 97 |
| Corporate and Other [Member] | ||
| Assets [Abstract] | ||
| Consolidated total assets | $ 4,706 | $ 4,962 |