Schedule of Revenues by Major Sources (Detail) - Truck, Parts and Other - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	$ 21,834.5	$ 17,154.3	$ 24,119.7
Trucks
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	16,799.7	13,164.8	19,989.5
Trucks | Truck Sales
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	15,989.7	12,466.9	19,225.2
Trucks | Revenues from extended warranties, operating leases and other
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	810.0	697.9	764.3
Parts Subsegment
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	4,944.3	3,912.9	4,024.9
Parts Subsegment | Parts
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	4,809.7	3,803.3	3,912.1
Parts Subsegment | Revenues from dealer services and other
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	134.6	109.6	112.8
Winch Sales and Other
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	$ 90.5	$ 76.6	$ 105.3