Derivative and Financial Instruments - Commodity GainLoss (Details) - Commodity Contract [Member] - USD ($) |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
| Sales and other operating revenues [Member] | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Gains (losses) from commodity derivatives | $ 141,000,000 | $ 45,000,000 | $ 77,000,000 |
| Other Income [Member] | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Gains (losses) from commodity derivatives | 4,000,000 | 7,000,000 | 0 |
| Purchased commodities [Member] | |||
| Derivative Instruments, Gain (Loss) [Line Items] | |||
| Gains (losses) from commodity derivatives | $ (118,000,000) | $ (41,000,000) | $ (61,000,000) |