Revenues - Retail Commercial Truck Dealership (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Revenues
Total revenues	$ 30,455.2	$ 29,527.4	$ 27,814.8
Retail commercial truck dealership
Revenues
Total revenues	3,521.1	3,684.3	3,541.3
New vehicle | Retail commercial truck dealership
Revenues
Total revenues	2,359.5	2,480.2	2,308.7
Used vehicle | Retail commercial truck dealership
Revenues
Total revenues	227.0	229.9	301.3
Finance and insurance, net | Retail commercial truck dealership
Revenues
Total revenues	18.8	21.9	20.5
Service and parts | Retail commercial truck dealership
Revenues
Total revenues	886.3	907.3	852.2
Other | Retail commercial truck dealership
Revenues
Total revenues	$ 29.5	$ 45.0	$ 58.6