Derivatives (Effect of Commodity Derivative Instruments in Statements of Income) (Detail) - Commodity derivatives - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	$ 64	$ (340)
Sales and other operating revenues
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	2	0
Cost of revenues
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	61	(342)
Other income
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	$ 1	$ 2