Schedule of Other Current Assets (Detail) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Disclosure Schedule Of Other Current Assets [Abstract]
Accrued payroll and related	$ 173	$ 199
Prepaid expenses	212	192
Sales and use tax	153	159
Other	154	156
Total other current assets	$ 519	$ 507