Derivatives (Effect of Commodity Derivative Instruments in Statements of Income) (Detail) - Commodity derivatives - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	$ (340)	$ (75)
Sales and other operating revenues
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	0	(10)
Cost of revenues
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	(342)	(65)
Other income
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss)	$ 2	$ 0