Summary of Significant Accounting Policies - Summary of Accrued Warranty Obligation (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Warranty reserve
Balance at the beginning of the year	$ 25	$ 4	$ 4
Acquisition	0	21	0
Warranty expense	30	13	7
Warranty payments	(33)	(13)	(7)
Balance at the end of the year	$ 22	$ 25	$ 4