DEBT - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			$ 3,019
Ending balance	$ 2,658
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(46)	$ (45)	(21)	$ (22)	$ (9)	$ (6)
Other comprehensive loss before reclassifications	3	(1)	(24)	(4)	(13)	(3)
Reclassification to Income Statement	0	0	0	0	0	0
Net other comprehensive loss	3	(1)	(24)	(4)	(13)	(3)
Ending balance	$ (43)	$ (46)	$ (45)	$ (26)	$ (22)	$ (9)