Estimated Value of Returned Goods Assets and Related Return Liabilities (Detail) - Truck, Parts and Other - USD ($) $ in Millions	Jun. 30, 2024	Dec. 31, 2023
Trucks
Entity Wide Information Revenue From External Customer [Line Items]
Other current assets	$ 120.3	$ 147.3
Accounts payable, accrued expenses and other	123.3	149.5
Other noncurrent assets, net	161.6	186.7
Other liabilities	169.6	196.4
Assets	281.9	334.0
Liabilities	292.9	345.9
Parts Subsegment
Entity Wide Information Revenue From External Customer [Line Items]
Accounts payable, accrued expenses and other	223.5	216.3
Other noncurrent assets, net	90.7	86.8
Assets	90.7	86.8
Liabilities	$ 223.5	$ 216.3