SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Non-Cash Impairments of Proved and Unproved Property and Equipment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Oil and Gas Properties, Proved
Schedule Of Significant Accounting Policies [Line Items]
Impairment of Oil and Gas properties	$ 328	$ 0	$ 427
Oil And Gas Properties, Unproved
Schedule Of Significant Accounting Policies [Line Items]
Impairment of Oil and Gas properties	224	246	272
United States | Oil and Gas Properties, Proved
Schedule Of Significant Accounting Policies [Line Items]
Impairment of Oil and Gas properties	265	0	61
United States | Oil And Gas Properties, Unproved
Schedule Of Significant Accounting Policies [Line Items]
Impairment of Oil and Gas properties	96	244	200
Canada | Oil and Gas Properties, Proved
Schedule Of Significant Accounting Policies [Line Items]
Impairment of Oil and Gas properties	0	0	366
Canada | Oil And Gas Properties, Unproved
Schedule Of Significant Accounting Policies [Line Items]
Impairment of Oil and Gas properties	0	2	72
Egypt | Oil and Gas Properties, Proved
Schedule Of Significant Accounting Policies [Line Items]
Impairment of Oil and Gas properties	63	0	0
North Sea | Oil And Gas Properties, Unproved
Schedule Of Significant Accounting Policies [Line Items]
Impairment of Oil and Gas properties	$ 128	$ 0	$ 0