Schedule of Revenues by Major Sources (Detail) - Truck, Parts and Other - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues		$ 31,564.3	$ 33,315.5	$ 27,314.3
Trucks
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues		24,838.4	26,846.4	21,486.2
Trucks | Truck Sales
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues		23,863.2	25,946.4	20,644.8
Trucks | Revenues from extended warranties, operating leases and other
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues		975.2	900.0	841.4
Parts Subsegment
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues		6,666.4	6,414.4	5,764.3
Parts Subsegment | Parts
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues		6,461.1	6,223.1	5,596.8
Parts Subsegment | Revenues from dealer services and other
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues		205.3	191.3	167.5
Winch Sales and Other
Entity Wide Information Revenue From External Customer [Line Items]
Total sales and revenues	[1]	$ 59.5	$ 54.7	$ 63.8

[1] Includes industrial winch business sales through October 31, 2024.