Impairments (Before Tax Impairment Charges) (Details) - USD ($) $ in Millions |
3 Months Ended | 12 Months Ended | ||
|---|---|---|---|---|
Dec. 31, 2021 |
Dec. 31, 2021 |
Dec. 31, 2020 |
Dec. 31, 2019 |
|
| Segment Reporting Information [Line Items] | ||||
| Impairments | $ 674 | $ 813 | $ 405 | |
| Alaska [Member] | Operating Segments [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Impairments | 5 | 0 | 0 | |
| Lower 48 [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Impairments | (89) | |||
| Lower 48 [Member] | Operating Segments [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Impairments | $ 84 | (8) | 804 | 402 |
| Canada | Operating Segments [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Impairments | 6 | 3 | 2 | |
| Europe, Middle East and North Africa [Member] | Operating Segments [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Impairments | (24) | 6 | 1 | |
| Asia Pacific [Member] | Operating Segments [Member] | ||||
| Segment Reporting Information [Line Items] | ||||
| Impairments | $ 695 | $ 0 | $ 0 | |