PROPERTY, PLANT AND EQUIPMENT - Property, Plant and Equipment Impairment in Bison (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 31, 2011	Dec. 31, 2018	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Schedule of Investments [Line Items]
Impairment of long-lived assets					$ 537
Bison
Schedule of Investments [Line Items]
Reduction in future revenue			$ 47	$ 47
Original contracts term	10 years
Bison
Schedule of Investments [Line Items]
Impairment of long-lived assets		$ 537