Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($)	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill deductible for income tax purposes	$ 71,000,000
Impairment of amortizable intangible assets	0
Amortization expense, intangible assets	111,000,000	$ 101,000,000
Amortization expense, computer software	$ 62,000,000	$ 53,000,000