SHAREHOLDERS' EQUITY - Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017
Equity [Abstract]
Cumulative translation adjustments, net	$ 266	$ 282
Unrealized loss on interest rate swaps, net	(10)	(12)
Unrecognized net loss and prior service cost, net	(383)	(335)
Accumulated other comprehensive loss	(127)	(65)
Income tax benefit on cumulative translation adjustment	2
Income tax benefit on unrealized loss on interest rate swap securities	4
Income tax benefit on prior service cost and net loss	$ 98	$ 154