EQUITY METHOD INVESTMENTS - Income (Loss) of Equity Method Investments (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments	$ (6)	$ 0	$ 1
Epic Pipeline
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments	(6)	0	0
Gray Oak Pipeline
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments	1	0	0
Wink To Webster Pipeline
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments	(1)	0	0
OMOG JV LLC
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments	0	0	0
HMW LLC
Schedule of Equity Method Investments [Line Items]
Income (loss) from equity method investments	$ 0	$ 0	$ 1