EQUITY METHOD INTERESTS - Summary of Investments (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Schedule of Equity Method Investments [Line Items]
Equity method interests	$ 1,524	$ 1,258
Altus Midstream Company
Schedule of Equity Method Investments [Line Items]
Equity method interests	$ 1,524	1,258
Altus Midstream Company | Gulf Coast Express Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Interest percentage	16.00%
Equity method interests	$ 284	291
Altus Midstream Company | EPIC Crude Holdings, LP
Schedule of Equity Method Investments [Line Items]
Interest percentage	15.00%
Equity method interests	$ 182	163
Altus Midstream Company | Permian Highway Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Interest percentage	26.70%
Equity method interests	$ 576	311
Altus Midstream Company | Breviloba, LLC (Shin Oak Pipeline)
Schedule of Equity Method Investments [Line Items]
Interest percentage	33.00%
Equity method interests	$ 482	$ 493