SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) - USD ($)	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Schedule Of Significant Accounting Policies [Line Items]
Impairments	$ 0	$ 4,472,000,000
Impairment for early termination of drilling rig leases		13,000,000
Inventory write-down		5,000,000
Goodwill	0	87,000,000
Gathering, processing and transmission facilities	671,000,000		$ 670,000,000
Accumulated depreciation	35,146,000,000		34,810,000,000
Receivables from contracts with customer, net	957,000,000		670,000,000
Revenue from non-customers	106,000,000	48,000,000
Restructuring cumulative cost incurred to date			79,000,000
Transaction, reorganization, and separation	0	27,000,000
Separation costs
Schedule Of Significant Accounting Policies [Line Items]
Transaction, reorganization, and separation		25,000,000
Consulting fees
Schedule Of Significant Accounting Policies [Line Items]
Transaction, reorganization, and separation		2,000,000
Egypt
Schedule Of Significant Accounting Policies [Line Items]
Goodwill		87,000,000
Oil and gas proved property
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties	$ 0	4,299,000,000
Oil and gas properties impaired, fair value		1,900,000,000
Oil and gas proved property | Discount Rate | Significant Unobservable Inputs (Level 3)
Schedule Of Significant Accounting Policies [Line Items]
Oil and gas properties, measurement inputs	0.10
Oil and gas proved property | U.S.
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties	$ 0	3,938,000,000
Oil and gas proved property | Egypt
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties	0	354,000,000
Oil and gas proved property | North Sea
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties	0	7,000,000
Gathering, processing, and transmission facilities
Schedule Of Significant Accounting Policies [Line Items]
Impairments		$ 68,000,000
Oil and gas properties impaired, fair value	46,000,000
Accumulated depreciation	$ 342,000,000		$ 323,000,000
Gathering, processing, and transmission facilities | Discount Rate | Significant Unobservable Inputs (Level 3)
Schedule Of Significant Accounting Policies [Line Items]
Oil and gas properties, measurement inputs	0.10
Sinopec | Apache Egypt
Schedule Of Significant Accounting Policies [Line Items]
Ownership percentage by noncontrolling owners	33.33%
Third-Party Investors | Altus Midstream Company
Schedule Of Significant Accounting Policies [Line Items]
Ownership percentage by noncontrolling owners	21.00%