Estimated Value of Returned Goods Assets and Related Return Liabilities (Detail) - Truck, Parts and Other - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Trucks
Entity Wide Information Revenue From External Customer [Line Items]
Other current assets	$ 116.7	$ 147.3
Accounts payable, accrued expenses and other	121.7	149.5
Other noncurrent assets, net	135.9	186.7
Other liabilities	144.7	196.4
Assets	252.6	334.0
Liabilities	266.4	345.9
Parts Subsegment
Entity Wide Information Revenue From External Customer [Line Items]
Other current assets	101.7	86.8
Accounts payable, accrued expenses and other	244.4	216.3
Assets	101.7	86.8
Liabilities	$ 244.4	$ 216.3