Equipment on Operating Leases - Additional Information (Detail) $ in Millions	Dec. 31, 2017 USD ($)
Financial Services
Property Subject to or Available for Operating Lease [Line Items]
Minimum lease payments receivable for operating leases, in 2018	$ 628.5
Minimum lease payments receivable for operating leases, in 2019	433.2
Minimum lease payments receivable for operating leases, in 2020	267.1
Minimum lease payments receivable for operating leases, in 2021	138.2
Minimum lease payments receivable for operating leases, in 2022	49.4
Minimum lease payments receivable for operating leases, thereafter	9.6
Truck, Parts and Other
Property Subject to or Available for Operating Lease [Line Items]
Annual amortization of deferred lease revenues, in 2018	188.9
Annual amortization of deferred lease revenues, in 2019	123.8
Annual amortization of deferred lease revenues, in 2020	69.5
Annual amortization of deferred lease revenues, in 2021	42.3
Annual amortization of deferred lease revenues, in 2022	4.5
Annual amortization of deferred lease revenues, thereafter	0.2
Annual maturities of the residual value guarantees, in 2018	287.8
Annual maturities of the residual value guarantees, in 2019	269.9
Annual maturities of the residual value guarantees, in 2020	209.5
Annual maturities of the residual value guarantees, in 2021	79.8
Annual maturities of the residual value guarantees, in 2022	54.2
Annual maturities of the residual value guarantees, thereafter	$ 8.6