EQUITY METHOD INTERESTS - Summary of Investments (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Equity method interests	$ 527	$ 121
Altus Midstream Company
Schedule of Equity Method Investments [Line Items]
Equity method interests	$ 527	$ 91
Altus Midstream Company | Gulf Coast Express Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Interest	16.00%	15.00%
Equity method interests	$ 251	$ 91
Altus Midstream Company | EPIC Crude Holdings, LP
Schedule of Equity Method Investments [Line Items]
Interest	15.00%	0.00%
Equity method interests	$ 105	$ 0
Altus Midstream Company | Permian Highway Pipeline LLC
Schedule of Equity Method Investments [Line Items]
Interest	26.70%	0.00%
Equity method interests	$ 171	$ 0