SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES - Additional Information (Details) - USD ($)	3 Months Ended					9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Dec. 31, 2019
Schedule Of Significant Accounting Policies [Line Items]
Impairments	$ 0	$ 20,000,000	$ 4,500,000,000	$ 9,000,000		$ 4,492,000,000	$ 249,000,000
Impairments of oil and gas properties	0			9,000,000		4,492,000,000	249,000,000
Goodwill	0		87,000,000	0		87,000,000	0
Impairment for early termination of drilling rig leases			13,000,000
Inventory write-down			5,000,000
Divested unproved properties and leasehold	0			0		0	149,000,000
Receivables from contracts with customer, net	770,000,000					770,000,000		$ 945,000,000
Transaction, reorganization, and separation	7,000,000			7,000,000		44,000,000	17,000,000
Separation costs
Schedule Of Significant Accounting Policies [Line Items]
Transaction, reorganization, and separation						41,000,000
Consulting fees
Schedule Of Significant Accounting Policies [Line Items]
Transaction, reorganization, and separation						2,000,000
Office closure
Schedule Of Significant Accounting Policies [Line Items]
Transaction, reorganization, and separation						1,000,000
Reorganization
Schedule Of Significant Accounting Policies [Line Items]
Restructuring cumulative cost incurred to date	69,000,000					69,000,000
Oil and gas, purchased
Schedule Of Significant Accounting Policies [Line Items]
Oil and gas production revenues	74,000,000			30,000,000		237,000,000	72,000,000
Cost of goods and services sold	75,000,000			23,000,000		207,000,000	60,000,000
Altus Midstream
Schedule Of Significant Accounting Policies [Line Items]
Assets held-for-sale, fair value				18,000,000			18,000,000
Oklahoma And Texas
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties					$ 240,000,000
Oil and gas proved property
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties	$ 0			0		$ 4,319,000,000	86,000,000
Oil and gas properties impaired, fair value		$ 1,900,000,000	32,000,000
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					0.10
Oil and gas proved property | U.S.
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties	$ 0		3,900,000,000	0		$ 3,938,000,000	86,000,000
Oil and gas proved property | Egypt
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties	0		354,000,000	0		374,000,000	0
Oil and gas proved property | North Sea
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties	0		7,000,000	0		7,000,000	0
Oil and gas proved property | Oklahoma And Texas
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties					86,000,000
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					$ 46,000,000
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					0.10
Oil and gas unproved properties
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties	$ 36,000,000			12,000,000		$ 86,000,000	223,000,000
Oil and gas unproved properties | U.S.
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties	34,000,000			10,000,000		80,000,000	217,000,000
Oil and gas unproved properties | Egypt
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties	$ 2,000,000			$ 2,000,000		$ 6,000,000	$ 6,000,000
Oil and gas unproved properties | Oklahoma And Texas
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties					149,000,000
Divested unproved properties and leasehold					149,000,000
Other working capital | Oklahoma And Texas
Schedule Of Significant Accounting Policies [Line Items]
Impairments of oil and gas properties					$ 5,000,000
Altus Midstream Company
Schedule Of Significant Accounting Policies [Line Items]
Ownership percentage by noncontrolling owners	21.00%					21.00%
Sinopec | Apache’s Egypt Oil And Gas Business
Schedule Of Significant Accounting Policies [Line Items]
Ownership percentage by noncontrolling owners	33.33%					33.33%