Reclassifications Out of Accumulated Other Comprehensive Income (Parenthetical) (Detail) (Truck, Parts and Other, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pension plans, prior service costs, pre-tax expense	$ 1.3
Pension plans, actuarial (loss), pre-tax expense	(41.7)
Cost of sales and revenues
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pension plans, prior service costs, pre-tax expense	0.4
Pension plans, actuarial (loss), pre-tax expense	21.4
SG&A
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pension plans, prior service costs, pre-tax expense	0.6
Pension plans, actuarial (loss), pre-tax expense	20.3
R&D
Accumulated Other Comprehensive Income (Loss) [Line Items]
Pension plans, prior service costs, pre-tax expense	$ 0.3