INCOME TAXES - Reconciliation of Beginning and Ending Amount of Unrecognized Tax Benefits (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance at beginning of year	$ 26	$ 15	$ 19	$ 0
Additions based on tax positions related to the current year	12	15	19
Reductions for tax positions of prior years	(1)	(19)	0
Balance at end of year	$ 26	$ 15	$ 19	$ 0