Financing Receivables by Aging Category (Detail) - Financial Services - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	$ 11,990.8	$ 10,745.4
Financing Receivables	12,055.8	10,780.0
31 - 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	31.7	18.0
Greater than 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	33.3	16.6
Dealer | Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	2,907.4	2,342.1
Financing Receivables	2,907.4	2,342.3
Dealer | Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	1,645.6	1,464.6
Financing Receivables	1,645.6	1,464.6
Dealer | 31 - 60 days past due | Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due		0.1
Dealer | Greater than 60 days past due | Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due		0.1
Customer Retail | Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	6,297.1	5,835.6
Financing Receivables	6,347.7	5,857.5
Customer Retail | Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, current and up to 30 days past due	1,140.7	1,103.1
Financing Receivables	1,155.1	1,115.6
Customer Retail | 31 - 60 days past due | Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	23.0	11.2
Customer Retail | 31 - 60 days past due | Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	8.7	6.7
Customer Retail | Greater than 60 days past due | Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	27.6	10.7
Customer Retail | Greater than 60 days past due | Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Financing receivables, past due	$ 5.7	$ 5.8