Property, Plant and Equipment (Detail) (USD $) In Millions, unless otherwise specified						12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Truck, Parts and Other	Dec. 31, 2012 Truck, Parts and Other	Dec. 31, 2013 Truck, Parts and Other Building and Building Improvements Minimum	Dec. 31, 2013 Truck, Parts and Other Building and Building Improvements Maximum	Dec. 31, 2013 Truck, Parts and Other Machinery Equipment And Production Tooling Minimum	Dec. 31, 2013 Truck, Parts and Other Machinery Equipment And Production Tooling Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life						10 years	40 years	3 years	12 years
Land				$ 238.5	$ 231.0
Buildings and improvements				1,024.9	960.1
Machinery, equipment and production tooling				3,345.8	2,678.6
Construction in progress				321.2	667.9
Property, Plant and Equipment, Gross, Total				4,930.4	4,537.6
Less allowance for depreciation				(2,417.1)	(2,224.7)
Property, plant and equipment, net	$ 2,513.3	$ 2,312.9	$ 1,973.3	$ 2,513.3	$ 2,312.9