SUPPLEMENTAL OIL AND GAS DISCLOSURES (Unaudited) - Principal Sources of Change In Discounted Future Net Cash Flows (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Extractive Industries [Abstract]
Sales, net of production costs	$ (5,335)	$ (4,158)	$ (3,479)
Net change in prices and production costs	3,902	3,651	(3,835)
Discoveries and improved recovery, net of related costs	3,889	2,273	1,153
Change in future development costs	47	(279)	309
Previously estimated development costs incurred during the period	910	719	986
Revision of quantities	(648)	(344)	(574)
Purchases of minerals in-place	6	9	8
Accretion of discount	1,216	952	1,313
Change in income taxes	(1,125)	(617)	1,070
Sales of minerals in-place	(1)	(809)	(52)
Change in production rates and other	777	626	567
Change in the discounted future net cash flows, Total	$ 3,638	$ 2,023	$ (2,534)