Estimated Value of Returned Goods Assets and Related Return Liabilities (Detail) - Truck, Parts and Other - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Trucks
Entity Wide Information Revenue From External Customer [Line Items]
Other current assets	$ 147.3	$ 183.0
Accounts payable, accrued expenses and other	149.5	185.0
Other noncurrent assets, net	186.7	284.6
Other liabilities	196.4	298.9
Assets	334.0	467.6
Liabilities	345.9	483.9
Parts Subsegment
Entity Wide Information Revenue From External Customer [Line Items]
Other current assets	86.8	77.7
Accounts payable, accrued expenses and other	216.3	181.4
Assets	86.8	77.7
Liabilities	$ 216.3	$ 181.4