EQUITY METHOD INTERESTS - Narrative (Details) - USD ($)	3 Months Ended
	Mar. 31, 2019	Sep. 30, 2019	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Equity method interests		$ 1,095,000,000	$ 121,000,000
Marine Well Containment Company
Schedule of Equity Method Investments [Line Items]
Equity method interests	$ 30,000,000
Gain (loss) on disposal of investment	$ 0
Altus Midstream Company
Schedule of Equity Method Investments [Line Items]
Difference between carrying amount and underlying equity amount		26,000,000	6,000,000
Equity method interests		$ 1,095,000,000	$ 91,000,000