Financing Receivables by Aging Category (Detail) - Financial Services - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	$ 8,978.9	$ 9,247.4
Financing Receivables	9,029.0	9,286.5
31 - 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	27.0	13.7
Greater than 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	23.1	25.4
Dealer | Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	1,736.0	1,949.8
Financing Receivables	1,736.5	1,950.1
Dealer | Wholesale | 31 - 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	0.3	0.0
Dealer | Wholesale | Greater than 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	0.2	0.3
Dealer | Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	1,446.8	1,561.3
Financing Receivables	1,446.8	1,561.3
Dealer | Retail | 31 - 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	0.0	0.0
Dealer | Retail | Greater than 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	0.0	0.0
Customer Retail | Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	4,826.6	4,733.6
Financing Receivables	4,865.8	4,761.4
Customer Retail | Fleet | 31 - 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	20.7	8.3
Customer Retail | Fleet | Greater than 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	18.5	19.5
Customer Retail | Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	969.5	1,002.7
Financing Receivables	979.9	1,013.7
Customer Retail | Owner/Operator | 31 - 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	6.0	5.4
Customer Retail | Owner/Operator | Greater than 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	$ 4.4	$ 5.6