Accumulated Other Comprehensive Income (Loss) - Summary of Components of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Accumulated other comprehensive income (loss), Beginning balance	$ 1,403
Other comprehensive loss	(8)	$ (89)	$ (45)
Accumulated other comprehensive income (loss), Ending balance	1,183	1,403
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated other comprehensive income (loss), Beginning balance	(134)
Other comprehensive loss	(8)	(89)	$ (45)
Accumulated other comprehensive income (loss), Ending balance	$ (142)	$ (134)