Income Taxes - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Income Tax Disclosure [Abstract]
Effective income tax rate	32.80%	32.40%
Unrecognized tax benefits	$ 25
Unrecognized tax benefits, increase resulting from current period tax positions	1
Unrecognized tax benefits that, if recognized, would impact the effective tax rate	16
Net cash payments for income taxes, net of refunds	$ 43	$ 58