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Goodwill and Intangible Assets, Net (Intangible Assets) (Details) - USD ($) $ in Millions | Dec. 31, 2017 | Dec. 31, 2016
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Indefinite-lived Intangible Assets by Segment [Line Items] |  |
Franchise rights - indefinite-lived | $ 572.2 | $ 589.4
AN Reportable Segment, Domestic [Member] |  |
Indefinite-lived Intangible Assets by Segment [Line Items] |  |
Franchise rights - indefinite-lived | 168.0 |
AN Reportable Segment, Import [Member] |  |
Indefinite-lived Intangible Assets by Segment [Line Items] |  |
Franchise rights - indefinite-lived | 108.9 |
AN Reportable Segment, Premium Luxury [Member] |  |
Indefinite-lived Intangible Assets by Segment [Line Items] |  |
Franchise rights - indefinite-lived | $ 295.3 |

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- Definition Carrying amount (original costs adjusted for previously recognized amortization and impairment) as of the balance sheet date for the rights acquired through a franchise arrangement having an indefinite period of benefit. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 350 -SubTopic 30 -Section 50 -Paragraph 2 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=66006027&loc=d3e16323-109275 + Details
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- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
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- Details
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- Details
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