Revenues - Contract Balances (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Dec. 31, 2019
Contract Balances
Accounts receivable, net	$ 616.3	$ 960.3
Unearned revenues	242.3	262.9
Revenue recognized from unearned revenue	118.5
Contracts in transit
Contract Balances
Accounts receivable, net	95.0	291.1
Vehicle receivables
Contract Balances
Accounts receivable, net	191.8	249.8
Manufacturer receivables
Contract Balances
Accounts receivable, net	161.2	244.6
Trade receivables
Contract Balances
Accounts receivable, net	$ 161.8	$ 164.7

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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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