Property, Plant and Equipment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property, Plant and Equipment [Line Items]
Property, plant and equipment, net	$ 2,260.0	$ 2,176.4	$ 2,313.3
Truck, Parts and Other
Property, Plant and Equipment [Line Items]
Land	221.2	222.1
Buildings and improvements	1,134.1	1,061.7
Machinery, equipment and production tooling	3,285.2	3,237.1
Construction in progress	352.8	248.4
Property, Plant and Equipment, Gross, Total	4,993.3	4,769.3
Less allowance for depreciation	(2,733.3)	(2,592.9)
Property, plant and equipment, net	$ 2,260.0	$ 2,176.4
Truck, Parts and Other | Building and Building Improvements | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	10 years
Truck, Parts and Other | Building and Building Improvements | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Truck, Parts and Other | Machinery Equipment And Production Tooling | Minimum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Truck, Parts and Other | Machinery Equipment And Production Tooling | Maximum
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	12 years