Inventories (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Inventory [Line Items]
Total inventories	$ 3,509.1	$ 3,129.0
Retail automotive dealership new vehicles
Inventory [Line Items]
Total inventories	1,326.5	869.1
Retail automotive dealership used vehicles
Inventory [Line Items]
Total inventories	1,279.6	1,420.0
Retail automotive parts, accessories, and other
Inventory [Line Items]
Total inventories	145.6	126.4
Retail commercial truck dealership vehicles and parts
Inventory [Line Items]
Total inventories	506.2	436.7
Commercial vehicle distribution vehicles, parts, and engines
Inventory [Line Items]
Total inventories	$ 251.2	$ 276.8