Revenues - Retail Commercial Truck Dealership (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Revenues
Total revenues	$ 7,662.3	$ 7,696.7	$ 15,266.8	$ 15,144.5
Retail commercial truck dealership
Revenues
Total revenues	943.6	892.3	1,767.3	1,684.1
New truck | Retail commercial truck dealership
Revenues
Total revenues	655.6	615.4	1,182.8	1,109.6
Used truck | Retail commercial truck dealership
Revenues
Total revenues	52.7	48.7	116.5	111.1
Finance and insurance, net | Retail commercial truck dealership
Revenues
Total revenues	4.0	4.2	8.5	9.5
Service and parts | Retail commercial truck dealership
Revenues
Total revenues	226.7	219.2	448.7	442.8
Other | Retail commercial truck dealership
Revenues
Total revenues	$ 4.6	$ 4.8	$ 10.8	$ 11.1