Summary of Impaired Loans and Specific Reserve (Cash Basis Method) (Detail) (Financial Services, USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Interest income recognized:
Interest income recognized on a cash basis	$ 0.4	$ 0.5	$ 1.6	$ 2.2
Dealer wholesale financing
Interest income recognized:
Interest income recognized on a cash basis			0.1	0.3
Retail | Fleet
Interest income recognized:
Interest income recognized on a cash basis	0.2	0.3	0.9	1.2
Retail | Owner/Operator
Interest income recognized:
Interest income recognized on a cash basis	$ 0.2	$ 0.2	$ 0.6	$ 0.7