Goodwill and Other Intangible Assets - Additional Information (Detail) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Goodwill And Intangible Assets Disclosure [Abstract]
Goodwill deductible for income tax purposes	$ 50,000,000
Impairment of amortizable intangible assets	0
Amortization expense, intangible assets	425,000,000	$ 408,000,000	$ 404,000,000
Amortization expense, computer software	$ 232,000,000	$ 219,000,000	$ 217,000,000