Schedule of Accounts Payable and Other Current Liabilities (Detail) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Accounts Payable and Other Current Liabilities [Abstract]
Accounts payable	$ 359	$ 343
Accrued sales and use taxes	218	206
Accrued payroll and related	176	173
Public liability and property damage insurance liabilities – current	145	141
Deferred revenue – current	135	114
Accrued commissions	117	86
Accrued insurance	103	70
Other	366	355
Accounts payable and other current liabilities	$ 1,619	$ 1,488