FLOOR PLAN NOTES PAYABLE—NON-TRADE (Consist of) (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Debt Disclosure [Abstract]
Floor plan notes payable—new non-trade	$ 314.7	$ 715.9
Floor plan notes payable—used non-trade	294.0	0.0
Floor plan notes payable offset account	(81.5)	(78.6)
Total floor plan notes payable—non-trade, net	$ 527.2	637.3
Floor plan notes payable—non-trade, liabilities associated with assets held for sale		$ 9.1