SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Non-Cash Impairments of Proved and Unproved Property and Equipment (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Oil and gas proved property
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	$ 0	$ 4,299
Oil and gas unproved properties
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	18	19
U.S. | Oil and gas proved property
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	0	3,938
U.S. | Oil and gas unproved properties
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	16	17
Egypt | Oil and gas proved property
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	0	354
Egypt | Oil and gas unproved properties
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	2	2
North Sea | Oil and gas proved property
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	$ 0	$ 7