Amortized Cost Basis of Financing Receivables by Aging Category (Detail) - Financial Services - USD ($) $ in Millions	Jun. 30, 2022	Dec. 31, 2021
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	$ 12,637.9	$ 11,911.1
Current and up to 30 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	12,590.7	11,882.5
31 - 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	12.8	11.5
Greater than 60 days past due
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	34.4	17.1
Dealer
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	4,124.0	3,546.8
Dealer | Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	2,385.8	1,865.8
Dealer | Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	1,738.2	1,681.0
Dealer | Current and up to 30 days past due | Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	2,384.5	1,865.4
Dealer | Current and up to 30 days past due | Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	1,738.2	1,681.0
Dealer | 31 - 60 days past due | Wholesale
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	1.3	0.4
Customer Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	8,513.9	8,364.3
Customer Retail | Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	7,184.7	6,961.6
Customer Retail | Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	1,329.2	1,402.7
Customer Retail | Current and up to 30 days past due | Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	7,144.0	6,939.7
Customer Retail | Current and up to 30 days past due | Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	1,324.0	1,396.4
Customer Retail | 31 - 60 days past due | Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	9.6	9.3
Customer Retail | 31 - 60 days past due | Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	1.9	1.8
Customer Retail | Greater than 60 days past due | Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	31.1	12.6
Customer Retail | Greater than 60 days past due | Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Finance Receivable	$ 3.3	$ 4.5