Allowance for Credit Losses (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		$ 61.7	$ 65.7	$ 68.2
Provision for losses		8.1	(4.7)	(2.2)
Charge-offs		(9.8)	(1.7)	(2.5)
Recoveries		1.0	2.4	2.2
Ending Balance		61.0	61.7	65.7
Dealer | Wholesale
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		1.0	1.0	1.3
Provision for losses				(0.3)
Ending Balance		1.0	1.0	1.0
Dealer | Retail
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		1.8	6.5	7.5
Provision for losses		(0.1)	(4.7)	(1.0)
Ending Balance		1.7	1.8	6.5
Customer Retail
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		57.9	57.1	57.7
Provision for losses		8.0
Charge-offs		(9.8)	(1.6)	(2.5)
Recoveries		0.8	2.4	1.9
Ending Balance		56.9	57.9	57.1
Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	[1]	1.0	1.1	1.7
Provision for losses	[1]	0.2		(0.9)
Charge-offs	[1]		(0.1)
Recoveries	[1]	0.2		0.3
Ending Balance	[1]	$ 1.4	$ 1.0	$ 1.1

[1] Operating lease and other trade receivables.