DEBT AND FINANCING COSTS - Components of Financing Costs, Net (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Debt Disclosure [Abstract]
Interest expense	$ 110	$ 107	$ 222	$ 214
Amortization of debt issuance costs	3	2	5	4
Capitalized interest	0	(2)	0	(6)
Gain on extinguishment of debt	(1)	(140)	(1)	(140)
Interest income	(3)	(1)	(5)	(3)
Interest income from APA Corporation, net	(15)	0	(20)	0
Financing costs, net	$ 94	$ (34)	$ 201	$ 69