Derivatives - Effect of Commodity Derivative Instruments in Statements of Income (Detail) - Commodity derivatives - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2017 |
Mar. 31, 2016 |
|
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Gain (Loss) | $ (8) | $ (57) |
| Sales and other operating revenues | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Gain (Loss) | 16 | 6 |
| Cost of revenues | ||
| Derivative Instruments, Gain (Loss) [Line Items] | ||
| Gain (Loss) | $ (24) | $ (63) |