DERIVATIVE INSTRUMENTS AND HEDGING ACTIVITIES - Derivative Activities Recorded in the Statement of Consolidated Operations (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain (loss), net	$ (136)	$ 9	$ (120)
Unrealized gain (loss), net	(87)	(44)	103
Derivative instrument losses, net	(223)	(35)	(17)
Commodity Derivative Instruments
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain (loss), net	(135)	27	(81)
Unrealized gain (loss), net	11	(44)	103
Amortization of put premium, realized loss
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain (loss), net	0	0	(39)
Foreign currency derivative instruments
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain (loss), net	(1)	0	0
Unrealized gain (loss), net	(1)	1	0
Treasury-lock
Derivative Instruments, Gain (Loss) [Line Items]
Realized gain (loss), net	0	(18)	0
Pipeline capacity embedded derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss), net	(61)	8	0
Preferred Units embedded derivative
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized gain (loss), net	$ (36)	$ (9)	$ 0