Allowance for Credit Losses (Detail) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for losses		$ 5.9	$ 5.9
Dealer | Wholesale
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		6.0
Ending Balance		6.5
Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		9.3
Ending Balance		9.9
Financial Services
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		117.2	111.2
Provision for losses		5.9	5.9
Charge-offs		(4.4)	(6.8)
Recoveries		1.7	1.4
Currency translation and other		1.4	2.2
Ending Balance		121.8	113.9
Financial Services | Dealer | Wholesale
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		6.0	5.5
Provision for losses		0.3	0.0
Charge-offs			0.0
Recoveries		0.1	0.0
Currency translation and other		0.1	0.1
Ending Balance		6.5	5.6
Financial Services | Dealer | Retail
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		9.4	9.6
Provision for losses			(0.3)
Charge-offs			0.0
Recoveries			0.0
Currency translation and other			0.1
Ending Balance		9.4	9.4
Financial Services | Customer Retail
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		92.5	87.5
Provision for losses		5.0	5.9
Charge-offs		(4.2)	(6.5)
Recoveries		1.6	1.4
Currency translation and other		1.1	2.0
Ending Balance		96.0	90.3
Financial Services | Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	[1]	9.3	8.6
Provision for losses	[1]	0.6	0.3
Charge-offs	[1]	(0.2)	(0.3)
Recoveries	[1]		0.0
Currency translation and other	[1]	0.2	0.0
Ending Balance	[1]	$ 9.9	$ 8.6

[1] Operating leases and other trade receivables.