Summary of Significant Accounting Policies - Summary of Accrued Warranty Obligation (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Warranty reserve
Balance at the beginning of the year	$ 22	$ 25	$ 4
Acquisition	0	0	21
Warranty expense	31	30	13
Warranty payments	(32)	(33)	(13)
Balance at the end of the year	$ 21	$ 22	$ 25