Allowance for Credit Losses (Detail) - USD ($) $ in Millions		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017
Financing Receivable, Allowance for Credit Losses [Line Items]
Provision for losses		$ 14.8	$ 17.4
Dealer | Wholesale
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		6.0
Ending Balance		6.6
Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		9.3
Ending Balance		4.4
Financial Services
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		117.2	111.2
Provision for losses		14.8	17.4
Charge-offs		(22.0)	(18.3)
Recoveries		7.0	3.5
Currency translation and other		(1.3)	5.9
Ending Balance		115.7	119.7
Financial Services | Dealer | Wholesale
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		6.0	5.5
Provision for losses		0.6	0.4
Charge-offs		0.0	0.0
Recoveries		0.0	0.0
Currency translation and other		0.0	0.6
Ending Balance		6.6	6.5
Financial Services | Dealer | Retail
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		9.4	9.6
Provision for losses		(0.1)	(0.6)
Charge-offs		0.0	0.0
Recoveries		0.0	0.0
Currency translation and other		0.0	0.2
Ending Balance		9.3	9.2
Financial Services | Customer Retail
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance		92.5	87.5
Provision for losses		12.8	17.2
Charge-offs		(15.5)	(17.7)
Recoveries		6.7	3.3
Currency translation and other		(1.1)	4.5
Ending Balance		95.4	94.8
Financial Services | Other
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	[1]	9.3	8.6
Provision for losses	[1]	1.5	0.4
Charge-offs	[1]	(6.5)	(0.6)
Recoveries	[1]	0.3	0.2
Currency translation and other	[1]	(0.2)	0.6
Ending Balance	[1]	$ 4.4	$ 9.2

[1] Operating leases and other trade receivables.