SUPPLEMENTAL INFORMATION ON OIL AND NATURAL GAS OPERATIONS (Unaudited) - Standardized Measure of Discounted Future Net Cash Flows - Proved Crude Oil and Natural Gas Reserves (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Discounted Future Net Cash Flows Relating to Proved Oil and Gas Reserves, Standardized Measure [Abstract]
Future cash inflows	$ 40,681	$ 43,578	$ 12,922
Future development costs	(3,809)	(3,560)	(1,124)
Future production costs	(9,319)	(7,727)	(2,995)
Future production taxes	(2,905)	(2,935)	(929)
Future income tax expenses	(2,635)	(3,913)	(84)
Future net cash flows	22,013	25,443	7,790
10% discount to reflect timing of cash flows	(11,829)	(13,767)	(4,033)
Standardized measure of discounted future net cash flows	$ 10,184	$ 11,676	$ 3,757	$ 1,711