DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Schedule of Derivative Activities Recorded in the Statement of Consolidated Operations (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Realized gain (loss):
Derivative settlements, realized gain (loss)	$ 9	$ (81)	$ 24
Amortization of put premium, realized loss	0	(39)	(100)
Unrealized gain (loss)	(44)	103	(59)
Derivative instrument losses, net	$ (35)	$ (17)	$ (135)