(Income) or Expense Recognized in Earnings Related to Economic Hedges (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
Interest Rate Contract
Derivative [Line Items]
(Income) or expense recognized in earnings related to economic hedges	$ 1.0	$ 0.3
Interest Rate Contract | Financial Services | Interest and other borrowing expenses
Derivative [Line Items]
(Income) or expense recognized in earnings related to economic hedges	1.0	0.3
Foreign Exchange Contract
Derivative [Line Items]
(Income) or expense recognized in earnings related to economic hedges	(0.9)
Foreign Exchange Contract | Truck and Other | Cost of sales and revenues
Derivative [Line Items]
(Income) or expense recognized in earnings related to economic hedges		0.1
Foreign Exchange Contract | Truck and Other | Interest and other (income) expense, net
Derivative [Line Items]
(Income) or expense recognized in earnings related to economic hedges	(0.6)
Foreign Exchange Contract | Financial Services | Interest and other borrowing expenses
Derivative [Line Items]
(Income) or expense recognized in earnings related to economic hedges	$ (0.3)	$ (0.1)