SUPPLEMENTAL QUARTERLY FINANCIAL DATA (Unaudited) (Detail) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Oil and gas production revenues	$ 1,703	$ 1,976	$ 1,936	$ 1,733	$ 1,640	$ 1,389	$ 1,346	$ 1,512	$ 7,424	$ 6,423	$ 5,354
Gain on divestitures	13	1	2	7	11	296	(21)	341	23	627	21
Net income (loss) before income taxes	(344)	406	508	388	278	93	9	538	958	918	(1,682)
NET INCOME (LOSS) INCLUDING NONCONTROLLING INTEREST	(350)	161	269	206	518	105	613	267	286	1,503	(1,273)
Net income (loss) attributable to common stock	$ (381)	$ 81	$ 195	$ 145	$ 456	$ 63	$ 572	$ 213	$ 40	$ 1,304	$ (1,405)
Basic and diluted net loss per common share:
Basic net income (loss) per share (in USD per share)	$ (1.00)	$ 0.21	$ 0.51	$ 0.38	$ 1.20	$ 0.16	$ 1.50	$ 0.56	$ 0.11	$ 3.42	$ (3.71)
Diluted net income (loss) per share (in USD per share)	$ (1.00)	$ 0.21	$ 0.51	$ 0.38	$ 1.19	$ 0.16	$ 1.50	$ 0.56	$ 0.11	$ 3.41	$ (3.71)
Asset and leasehold impairments	$ 639	$ 49	$ 21	$ 16	$ 32	$ 160	$ 39	$ 23	$ 511	$ 8	$ 1,103