Exit and Disposal Costs - Additional Information (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Restructuring And Related Activities [Abstract]
Severance expense	$ 18	$ 55	$ 13
Accrued severance costs paid	48	52	57
Other facility and exit related costs	14		15
Other facility and exit related costs paid	3	2	$ 21
Accrued severance costs	6	36
Restructuring Reserve	$ 28	$ 17
Expected period for all payments for severance cost	all severance costs are expected to be paid in 2018