Equipment on Operating Leases - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014
Financial Services
Property Subject to or Available for Operating Lease [Line Items]
Minimum lease payments receivable for operating leases, in 2015	$ 527.7
Minimum lease payments receivable for operating leases, in 2016	377.2
Minimum lease payments receivable for operating leases, in 2017	243.4
Minimum lease payments receivable for operating leases, in 2018	118.1
Minimum lease payments receivable for operating leases, in 2019	37.0
Minimum lease payments receivable for operating leases, thereafter	6.8
Truck, Parts and Other
Property Subject to or Available for Operating Lease [Line Items]
Annual amortization of deferred lease revenues, in 2015	139.5
Annual amortization of deferred lease revenues, in 2016	100.5
Annual amortization of deferred lease revenues, in 2017	58.2
Annual amortization of deferred lease revenues, in 2018	33.3
Annual amortization of deferred lease revenues, in 2019	10.2
Annual amortization of deferred lease revenues, thereafter	0.1
Annual maturities of the residual value guarantees, in 2015	228.9
Annual maturities of the residual value guarantees, in 2016	169.1
Annual maturities of the residual value guarantees, in 2017	110.8
Annual maturities of the residual value guarantees, in 2018	64.4
Annual maturities of the residual value guarantees, in 2019	40.5
Annual maturities of the residual value guarantees, thereafter	$ 15.4