Costs Associated with Exit and Restructuring - Rollforward of Exit and Restructuring Accrual (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring Reserve [Roll Forward]
Balance at beginning of year	$ 10	$ 15
Charged to earnings	16	19	$ 40
Cash paid	(18)	(22)
WLAN Divestiture	0	(2)
Balance at the end of year	$ 8	$ 10	$ 15