Revenues - Contract Balances (Details) - USD ($) $ in Millions	6 Months Ended
Jun. 30, 2021	Dec. 31, 2020
Contract Balances
Accounts receivable, net	$ 913.3	$ 806.9
Unearned revenues	276.1	262.9
Unearned revenue recognized as revenue	122.3
Contracts in transit
Contract Balances
Accounts receivable, net	293.1	254.0
Vehicle receivables
Contract Balances
Accounts receivable, net	242.3	216.2
Manufacturer receivables
Contract Balances
Accounts receivable, net	178.4	193.6
Trade receivables
Contract Balances
Accounts receivable, net	$ 186.2	$ 135.3

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as current.

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