Derivative and Financial Instruments - Commodity Gain (Loss) (Details) - Commodity Contract [Member] - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2020 |
Mar. 31, 2019 |
|
| Sales and other operating revenues [Member] | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Gains (losses) from commodity derivatives | $ 47 | $ 19 |
| Other Income [Member] | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Gains (losses) from commodity derivatives | 2 | (1) |
| Purchased commodities [Member] | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Gains (losses) from commodity derivatives | $ (27) | $ (20) |