Pre- and Post-Modification Recorded Investment Balances by Portfolio Class (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
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Investment	$ 15.3	$ 4.1	$ 47.4	$ 29.7
Post-Modification Recorded Investment	14.5	4.1	45.9	29.5
Retail | Fleet
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Investment	14.7	3.4	45.3	24.5
Post-Modification Recorded Investment	13.9	3.4	43.8	24.3
Retail | Owner/Operator
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Investment	0.6	0.7	2.1	5.2
Post-Modification Recorded Investment	$ 0.6	$ 0.7	$ 2.1	$ 5.2