Restructuring Costs - Additional Information (Detail) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Aug. 31, 2014 Employees	Dec. 31, 2015 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Restructuring and Related Activities [Abstract]
Pre-tax restructuring charges		$ 8	$ 4	$ 15	$ 82
Pre-tax restructuring charges related to employee severance and benefit costs			$ 2	$ 10	$ 70
Number of employee positions eliminated | Employees	650