CAPITALIZED EXPLORATORY WELL COSTS - Capitalized Exploratory Well Costs Rollforward (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Increase (Decrease) in Capitalized Exploratory Well Costs that are Pending Determination of Proved Reserves [Roll Forward]
Capitalized well costs at beginning of year	$ 141	$ 159	$ 350
Additions pending determination of proved reserves	226	286	602
Divestitures and other	(38)	(100)	(82)
Reclassifications to proved properties	(56)	(179)	(647)
Charged to exploration expense	(76)	(25)	(64)
Capitalized well costs at end of year	$ 197	$ 141	$ 159