Finance and Other Receivables (Detail) - USD ($) $ in Millions		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Financial Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		$ 4,630.5	$ 4,147.8
Direct financing leases		3,459.4	3,211.7
Sales-type finance leases		735.3	781.1
Dealer wholesale financing		2,342.3	1,880.6
Operating lease receivables and other		174.6	161.1
Unearned interest: Finance leases		(387.5)	(368.0)
Finance and other receivables, net of deferred income		10,954.6	9,814.3
Less allowance for losses		(113.8)	(117.2)	$ (111.2)	$ (114.8)
Finance and other receivables, net		10,840.8	9,697.1
Loans and Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(103.8)	(101.9)
Dealer | Wholesale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(6.8)	(6.0)
Dealer | Wholesale | Financial Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(6.8)	(6.0)	(5.5)	(7.3)
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(3.2)	(9.3)
Other | Financial Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses	[1]	$ (3.2)	$ (9.3)	$ (8.6)	$ (8.3)

[1] Operating lease and other trade receivables.