Residual Value Obligation and Deferred Lease Revenue (Detail) - Truck, Parts and Other - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Property Subject to or Available for Operating Lease [Line Items]
Residual value guarantees	$ 909.8	$ 699.2
Deferred lease revenues	429.2	373.4
Residual value guarantees and deferred revenues, Total	$ 1,339.0	$ 1,072.6