Revenues - Retail Commercial Truck Dealership (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Revenues
Total revenues	$ 7,696.7	$ 7,468.5	$ 15,144.5	$ 14,807.5
Retail commercial truck dealership
Revenues
Total revenues	892.3	919.2	1,684.1	1,814.8
New truck | Retail commercial truck dealership
Revenues
Total revenues	615.4	616.4	1,109.6	1,216.6
Used truck | Retail commercial truck dealership
Revenues
Total revenues	48.7	52.4	111.1	101.9
Finance and insurance, net | Retail commercial truck dealership
Revenues
Total revenues	4.2	5.0	9.5	10.0
Service and parts | Retail commercial truck dealership
Revenues
Total revenues	219.2	232.1	442.8	460.1
Other | Retail commercial truck dealership
Revenues
Total revenues	$ 4.8	$ 13.3	$ 11.1	$ 26.2