DERIVATIVES - GAINS AND LOSSES ON DERIVATIVES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments	$ (423)	$ 233	$ 0
Oil Collars and Calls | Net sales
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments	1,064	(107)	0
Marketing Derivatives | Net sales
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments	(393)	1,804	2,254
Interest Rate Swaps | Gains (losses) on interest rate swaps and warrants, net
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments	(428)	122	0
Other | Gains (losses) on interest rate swaps and warrants, net | WES
Derivative Instruments, Gain (Loss) [Line Items]
Gain (loss) on derivative instruments	$ 5	$ 111	$ 0