Costs Associated with Exit and Restructuring - Summary of Exit and Restructuring Costs Incurred (Detail) - USD ($) $ in Millions	12 Months Ended			24 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2016	Dec. 31, 2015
Restructuring and Related Activities [Abstract]
Severance, stay bonuses, and other employee-related expenses	$ 17			$ 54	$ 37
Obligations for future non-cancellable lease payments	2			11	9
Total	$ 19	$ 40	$ 6	$ 65	$ 46