CAPITALIZED EXPLORATORY WELL COSTS - Aging of Suspended Well Balances (Details) $ in Millions	Dec. 31, 2020 USD ($) Project	Dec. 31, 2019 USD ($) Project	Dec. 31, 2018 USD ($) Project	Dec. 31, 2017 USD ($)
Extractive Industries [Abstract]
Exploratory well costs capitalized for a period of one year or less	$ 184	$ 108	$ 126
Exploratory well costs capitalized for a period greater than one year	13	33	33
Capitalized exploratory well costs	$ 197	$ 141	$ 159	$ 350
Number of projects with exploratory well costs capitalized for a period greater than one year | Project	5	2	2