Inventories (Components of Inventories, net) (Details) - USD ($) $ in Millions	Jun. 30, 2021	Dec. 31, 2020
Inventory [Line Items]
Total inventories	$ 2,238.8	$ 2,492.9
New vehicles
Inventory [Line Items]
Total inventories	872.5	1,556.6
Used vehicles
Inventory [Line Items]
Total inventories	1,238.4	835.9
Parts and accessories
Inventory [Line Items]
Total inventories	$ 127.9	$ 100.4

Amount after valuation and LIFO reserves of inventory expected to be sold, or consumed within one year or operating cycle, if longer.

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