Reclassifications Out of Accumulated Other Comprehensive Income (Parenthetical) (Detail) (Truck, Parts and Other, USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pension plans, Actuarial loss, pre- tax	$ 9.9	$ 21.2
Pension plans, Prior service costs, pre-tax	(0.6)
Cost of sales and revenues
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pension plans, Actuarial loss, pre- tax	5.6	11.5
Pension plans, Prior service costs, pre-tax	0.5	0.6
SG&A
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pension plans, Actuarial loss, pre- tax	4.3	9.6
Pension plans, Prior service costs, pre-tax	0.1
R&D
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pension plans, Actuarial loss, pre- tax		$ 0.1