Goodwill and Intangible Assets - Additional Information (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Dec. 31, 2014	Dec. 31, 2016
Fair Value Inputs, Assets, Quantitative Information [Line Items]
Amortization of Intangible Assets	$ 61	$ 95	$ 123	$ 196
Impairment of Intangible Assets	0	0
Goodwill accumulated impairment	0		$ 0			$ 0
Goodwill iImpairment loss	$ 0	$ 0			$ 0