Financing Receivables by Aging Category (Detail) (Financial Services, USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current and up to 30 days past due	$ 8,776.2	$ 8,270.5
31 - 60 days past due	17.2	17.8
Greater than 60 days past due	26.7	28.0
Financing Receivables	8,820.1	8,316.3
Dealer wholesale financing
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current and up to 30 days past due	1,611.7	1,537.0
31 - 60 days past due	1.7	0.5
Greater than 60 days past due	3.1	3.5
Financing Receivables	1,616.5	1,541.0
Retail | Dealer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current and up to 30 days past due	1,525.6	1,429.7
Financing Receivables	1,525.6	1,429.7
Retail | Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current and up to 30 days past due	4,417.5	3,934.8
31 - 60 days past due	9.2	9.4
Greater than 60 days past due	15.8	12.4
Financing Receivables	4,442.5	3,956.6
Retail | Owner/operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current and up to 30 days past due	1,221.4	1,369.0
31 - 60 days past due	6.3	7.9
Greater than 60 days past due	7.8	12.1
Financing Receivables	$ 1,235.5	$ 1,389.0