Amortized Cost Basis of Finance Receivables that are on Non-accrual Status (Detail) - Financial Services - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized cost basis of finance receivables that are on non-accrual status	$ 74.4	$ 49.7
Dealer | Retail
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized cost basis of finance receivables that are on non-accrual status	1.5	2.3
Customer Retail | Fleet
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized cost basis of finance receivables that are on non-accrual status	62.8	40.2
Customer Retail | Owner/Operator
Financing Receivable, Recorded Investment, Past Due [Line Items]
Amortized cost basis of finance receivables that are on non-accrual status	$ 10.1	$ 7.2