INVENTORIES - Schedule of Inventory (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022
Components of Inventory [Line Items]
Total inventories	$ 1,768.3	$ 959.2
Held-for-sale
Components of Inventory [Line Items]
Total inventories	84.5	3.4
New vehicles
Components of Inventory [Line Items]
Total inventories	1,252.5	527.7
Used vehicles
Components of Inventory [Line Items]
Total inventories	373.1	304.4
Parts and accessories
Components of Inventory [Line Items]
Total inventories	$ 142.7	$ 127.2