Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2014	Dec. 31, 2016
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Amortization of Intangible Assets	$ 62	$ 101
Impairment of Intangible Assets	0	0
Goodwill accumulated impairment	0			$ 0
Goodwill iImpairment loss	$ 0	$ 0	$ 0