Cumulative Effect of Change in Consolidated Balance Sheet (Detail) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Retained earnings	$ 13,402.4	$ 12,025.8
Truck, Parts and Other
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Inventories, net	2,198.8	1,976.0
Other liabilities	1,490.1	1,487.6
Retained earnings	13,402.4	12,025.8
Originally Reported | Truck, Parts and Other
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Inventories, net		1,768.3
Other liabilities		1,436.5
Retained earnings		11,869.2
Adjustment | Truck, Parts and Other
New Accounting Pronouncements Or Change In Accounting Principle [Line Items]
Inventories, net	257.1	207.7
Other liabilities		51.1
Retained earnings	$ 193.8	$ 156.6