Finance and Other Receivables (Detail) - USD ($) $ in Millions		Mar. 31, 2018	Dec. 31, 2017		Mar. 31, 2017	Dec. 31, 2016
Financial Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		$ 4,284.2	$ 4,147.8
Direct financing leases		3,306.8	3,211.7
Sales-type finance leases		738.7	781.1
Dealer wholesale financing		2,103.9	1,880.6
Operating lease receivables and other		165.3	161.1
Unearned interest: Finance leases		(373.2)	(368.0)
Finance and other receivables, net of deferred income		10,225.7	9,814.3
Less allowance for losses		(121.8)	(117.2)		$ (113.9)	$ (111.2)
Finance and other receivables, net		10,103.9	9,697.1	[1]
Loans and Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(105.4)	(101.9)
Dealer | Wholesale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(6.5)	(6.0)
Dealer | Wholesale | Financial Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(6.5)	(6.0)		(5.6)	(5.5)
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(9.9)	(9.3)
Other | Financial Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses	[2]	$ (9.9)	$ (9.3)		$ (8.6)	$ (8.6)

[1] The December 31, 2017 consolidated balance sheet has been derived from audited financial statements.

[2] Operating leases and other trade receivables.