Property, Plant and Equipment - Net Changes in Capitalized Exploratory Well Costs (Detail) $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) well	Dec. 31, 2020 USD ($) well	Dec. 31, 2019 USD ($) well
Property, Plant and Equipment [Abstract]
Beginning balance	$ 459	$ 584	$ 418
Additions to capitalized exploratory well costs pending the determination of proved reserves	222	111	224
Reclassifications to wells, facilities and equipment based on the determination of proved reserves	0	(111)	(58)
Capitalized exploratory well costs charged to expense	0	(125)	0
Ending balance	$ 681	$ 459	$ 584
Number of Wells at December 31 | well	35	22	31