Financing Receivables by Aging Category (Detail) (Financial Services, USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current and up to 30 days past due	$ 8,844.4	$ 8,776.2
31 - 60 days past due	21.3	17.2
Greater than 60 days past due	26.5	26.7
Financing Receivables	8,892.2	8,820.1
Dealer | Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current and up to 30 days past due	1,544.7	1,611.7
31 - 60 days past due	1.0	1.7
Greater than 60 days past due	2.9	3.1
Financing Receivables	1,548.6	1,616.5
Dealer | Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current and up to 30 days past due	1,503.0	1,525.6
Financing Receivables	1,503.0	1,525.6
Customer Retail | Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current and up to 30 days past due	4,619.5	4,417.5
31 - 60 days past due	12.0	9.2
Greater than 60 days past due	15.3	15.8
Financing Receivables	4,646.8	4,442.5
Customer Retail | Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Current and up to 30 days past due	1,177.2	1,221.4
31 - 60 days past due	8.3	6.3
Greater than 60 days past due	8.3	7.8
Financing Receivables	$ 1,193.8	$ 1,235.5