Recorded Investment for Finance Receivables that are on Non-accrual Status (Detail) (Financial Services, USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Schedule Of Financing Receivables [Line Items]
Recorded investment of finance receivables that are on non-accrual status	$ 55.3	$ 57.7
Dealer wholesale financing
Schedule Of Financing Receivables [Line Items]
Recorded investment of finance receivables that are on non-accrual status	9.1	3.1
Retail | Dealer
Schedule Of Financing Receivables [Line Items]
Recorded investment of finance receivables that are on non-accrual status		0.1
Retail | Fleet
Schedule Of Financing Receivables [Line Items]
Recorded investment of finance receivables that are on non-accrual status	36.7	42.8
Retail | Owner/Operator
Schedule Of Financing Receivables [Line Items]
Recorded investment of finance receivables that are on non-accrual status	$ 9.5	$ 11.7