SUPPLEMENTAL OIL AND GAS DISCLOSURES (Unaudited) - Principal Sources of Change In Discounted Future Net Cash Flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Extractive Industries [Abstract]
Sales, net of production costs	$ (2,422)	$ (4,291)	$ (5,335)
Net change in prices and production costs	(5,753)	(3,034)	3,902
Discoveries and improved recovery, net of related costs	751	2,042	3,889
Change in future development costs	20	(75)	47
Previously estimated development costs incurred during the period	576	983	910
Revision of quantities	(418)	(741)	(648)
Purchases of minerals in-place	0	0	6
Accretion of discount	1,236	1,693	1,216
Change in income taxes	1,533	720	(1,125)
Sales of minerals in-place	(104)	(817)	(1)
Change in production rates and other	11	(319)	777
Change in the discounted future net cash flows, Total	$ (4,570)	$ (3,839)	$ 3,638