Schedule of Revenues by Major Sources (Detail) - Truck, Parts and Other - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	$ 27,314.3	$ 21,834.5	$ 17,154.3
Trucks
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	21,486.2	16,799.7	13,164.8
Trucks | Truck Sales
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	20,644.8	15,989.7	12,466.9
Trucks | Revenues from extended warranties, operating leases and other
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	841.4	810.0	697.9
Parts Subsegment
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	5,764.3	4,944.3	3,912.9
Parts Subsegment | Parts
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	5,596.8	4,809.7	3,803.3
Parts Subsegment | Revenues from dealer services and other
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	167.5	134.6	109.6
Winch Sales and Other
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	$ 63.8	$ 90.5	$ 76.6