Finance and Other Receivables (Detail) - USD ($) $ in Millions		Jun. 30, 2018	Dec. 31, 2017		Jun. 30, 2017	Dec. 31, 2016
Financial Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Loans		$ 4,436.1	$ 4,147.8
Direct financing leases		3,285.5	3,211.7
Sales-type finance leases		712.5	781.1
Dealer wholesale financing		2,069.7	1,880.6
Operating lease receivables and other		157.8	161.1
Unearned interest: Finance leases		(363.4)	(368.0)
Finance and other receivables, net of deferred income		10,298.2	9,814.3
Less allowance for losses		(112.7)	(117.2)		$ (119.0)	$ (111.2)
Finance and other receivables, net		10,185.5	9,697.1	[1]
Loans and Leases
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(102.7)	(101.9)
Dealer | Wholesale
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(6.2)	(6.0)
Dealer | Wholesale | Financial Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(6.2)	(6.0)		(5.9)	(5.5)
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses		(3.8)	(9.3)
Other | Financial Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Less allowance for losses	[2]	$ (3.8)	$ (9.3)		$ (9.2)	$ (8.6)

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

[2] Operating leases and other trade receivables.