DEBT AND FINANCING COSTS - Components of Financing Costs, Net (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2021	Mar. 31, 2020
Debt Disclosure [Abstract]
Interest expense		$ 112	$ 107
Amortization of debt issuance costs		2	2
Capitalized interest		0	(4)
Interest income		(2)	(2)
Interest income from APA Corporation, net		(5)	0
Financing costs, net	[1]	$ 107	$ 103

[1] Includes amounts of $5 million associated with APA Corporation for the first quarter of 2021. Refer to Note 2—Transactions with Parent Affiliate.