DEBT - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
AOCI Attributable to Parent, Net of Tax
Beginning balance	$ 3,019
Ending balance	2,651	$ 3,019
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
AOCI Attributable to Parent, Net of Tax
Beginning balance	(21)	(6)	$ 0
Other comprehensive loss before reclassifications	(18)	(15)	(6)
Reclassification to Income Statement	0	0	0
Net other comprehensive loss	(18)	(15)	(6)
Ending balance	$ (39)	$ (21)	$ (6)