Estimated Value of Returned Goods Assets and Related Return Liabilities (Detail) - Truck, Parts and Other - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Trucks
Significant Accounting Policies [Line Items]
Other current assets	$ 255.7	$ 179.0
Accounts payable, accrued expenses and other	264.0	195.2
Other noncurrent assets, net	403.6	448.9
Other liabilities	423.9	468.9
Assets	659.3	627.9
Liabilities	687.9	664.1
Parts Subsegment
Significant Accounting Policies [Line Items]
Accounts payable, accrued expenses and other	172.1	142.0
Other noncurrent assets, net	72.9	62.2
Assets	72.9	62.2
Liabilities	$ 172.1	$ 142.0