Finance and Other Receivables (Detail) - USD ($) $ in Millions		Sep. 30, 2025	Dec. 31, 2024	Sep. 30, 2024	Dec. 31, 2023
Financial Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		$ 10,242.6	$ 9,442.4
Finance leases		5,243.0	4,906.6
Operating lease receivables and other		167.3	166.4
Finance and other receivables, net of deferred income		20,192.7	19,459.5
Less allowance for losses		(177.9)	(145.2)	$ (146.2)	$ (133.0)
Finance and other receivables, net		20,014.8	19,314.3
Loans and Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(172.4)	(139.2)
Dealer | Wholesale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(2.9)	(3.0)
Dealer | Wholesale | Financial Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Dealer wholesale financing		4,539.8	4,944.1
Less allowance for losses		(2.9)	(3.0)	(3.0)	(2.7)
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(2.6)	(3.0)
Other | Financial Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses	[1]	$ (2.6)	$ (3.0)	$ (2.9)	$ (3.3)

[1] Operating leases and other trade receivables.