Summary of Impaired Loans and Specific Reserve (Detail) (Financial Services, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
Impaired loans with a specific reserve	$ 22.4	$ 54.3
Associated allowance	(4.1)	(10.7)
Net carrying amount of impaired loans	18.3	43.6
Average recorded investment	39.7	53.6
Dealer wholesale financing
Financing Receivable, Impaired [Line Items]
Impaired loans with a specific reserve	8.5	3.6
Associated allowance	(1.4)	(2.2)
Net carrying amount of impaired loans	7.1	1.4
Average recorded investment	5.8	9.4
Retail | Fleet
Financing Receivable, Impaired [Line Items]
Impaired loans with a specific reserve	10.8	43.9
Associated allowance	(2.1)	(7.3)
Net carrying amount of impaired loans	8.7	36.6
Average recorded investment	28.9	35.0
Retail | Owner/operator
Financing Receivable, Impaired [Line Items]
Impaired loans with a specific reserve	3.1	6.8
Associated allowance	(0.6)	(1.2)
Net carrying amount of impaired loans	2.5	5.6
Average recorded investment	$ 5.0	$ 9.2