REDEMABLE NONCONTROLLING INTEREST - ALTUS - Activity Related to Preferred Units (Details) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2021 USD ($) shares	Jun. 30, 2020 USD ($)	Jun. 30, 2021 USD ($) shares	Jun. 30, 2020 USD ($) shares	Dec. 31, 2020 USD ($) shares
Increase (Decrease) in Temporary Equity [Roll Forward]
Beginning balance			$ 608
Ending balance	$ 617		617		$ 608
Altus Preferred Unit limited partners
Increase (Decrease) in Temporary Equity [Roll Forward]
Beginning balance	605	$ 573	608	$ 555	555
Dividends payable to Altus Preferred Unit limited partners	(12)		(11)
Allocation of Altus Midstream LP net income	24	19	43	37
Ending balance	617	$ 592	617	$ 592	$ 608
Altus Midstream LP
Increase (Decrease) in Temporary Equity [Roll Forward]
Preferred Units embedded derivative	125		125
Redeemable noncontrolling interest, net of embedded derivative liability	$ 742		$ 742
Preferred units, redemption terms, internal rate of return	11.50%		11.50%
Preferred units, invested capital	$ 813		$ 813
Preferred units, redemption value	$ 721		$ 721
Altus Midstream LP | Altus Preferred Unit limited partners
Movement In Preferred Units [Roll Forward]
Preferred units: beginning of period (in shares) | shares			660,694	638,163	638,163
Distribution of in-kind additional preferred units (in shares) | shares					22,531
Preferred units: end of period (in shares) | shares	660,694		660,694		660,694
Increase (Decrease) in Temporary Equity [Roll Forward]
Beginning balance			$ 608	$ 555	$ 555
Distribution of in-kind additional Preferred Units					0
Cash distributions to Altus Preferred Unit limited partners			(23)		(23)
Dividends payable to Altus Preferred Unit limited partners			(11)
Allocation of Altus Midstream LP net income			39		76
Accreted value adjustment			4
Ending balance	$ 617		$ 617		$ 608
Preferred units, redemption terms, multiple of invested capital	1.3		1.3