SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Non-Cash Impairments of Proved and Unproved Property and Equipment (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	$ 0		$ 9	$ 4,492	$ 249
Oil and gas proved property
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	0		0	4,319	86
Oil and gas unproved properties
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	36		12	86	223
U.S. | Oil and gas proved property
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	0	$ 3,900	0	3,938	86
U.S. | Oil and gas unproved properties
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	34		10	80	217
Egypt | Oil and gas proved property
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	0	354	0	374	0
Egypt | Oil and gas unproved properties
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	2		2	6	6
North Sea | Oil and gas proved property
Schedule Of Significant Accounting Policies [Line Items]
Asset impairments for property and equipment	$ 0	$ 7	$ 0	$ 7	$ 0