Pre- and Post-Modification Recorded Investment Balances by Portfolio Class (Detail) (Financial Services, USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Investment	$ 12.9
Post-Modification Recorded Investment	12.2
Retail | Fleet
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Investment	11.9
Post-Modification Recorded Investment	11.2
Retail | Owner/Operator
Financing Receivable, Modifications [Line Items]
Pre-Modification Recorded Investment	1.0
Post-Modification Recorded Investment	$ 1.0