Financing Receivables by Aging Category (Detail) - Financial Services - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	$ 9,000.6	$ 9,247.4
Financing Receivables	9,042.4	9,286.5
31 - 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	22.4	13.7
Greater than 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	19.4	25.4
Dealer | Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	1,763.2	1,949.8
Financing Receivables	1,764.0	1,950.1
Dealer | Wholesale | 31 - 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	0.6	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	1,421.7	1,561.3
Financing Receivables	1,421.7	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	4,870.7	4,733.6
Financing Receivables	4,900.5	4,761.4
Customer Retail | Fleet | 31 - 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	15.9	8.3
Customer Retail | Fleet | Greater than 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	13.9	19.5
Customer Retail | Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	945.0	1,002.7
Financing Receivables	956.2	1,013.7
Customer Retail | Owner/Operator | 31 - 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	5.9	5.4
Customer Retail | Owner/Operator | Greater than 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	$ 5.3	$ 5.6