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Financial Instruments And Fair Value Measurements (Nonfinancial Assets Measured on a Nonrecurring Basis) (Details) $ in Millions | 3 Months Ended | 6 Months Ended |
--- | --- | --- | ---
Jun. 30, 2020 USD ($) | Mar. 31, 2020 USD ($) store | Jun. 30, 2019 USD ($) | Jun. 30, 2020 USD ($) | Jun. 30, 2019 USD ($) | Dec. 31, 2019 USD ($)
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Gain/(Loss) on goodwill | $ 0.0 |  | $ 0.0 | $ (318.3) | $ 0.0 |
Goodwill impairment | 0.0 |  | 0.0 | 318.3 | 0.0 |
Franchise rights impairment, number of stores | store |  | 8 |  |  |  |
Franchise rights impairment | 0.0 |  | 9.6 | 57.5 | 9.6 |
Fair Value, Nonrecurring [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Gain/(Loss) on goodwill |  | $ (318.3) |  |  | 0.0 |
Gain/(Loss) on franchise rights and other |  |  |  | (59.9) | (9.6) |
Gain/(Loss) on right-of-use assets |  |  |  | (0.4) | (0.2) |
Gain/(Loss) on assets held and used |  |  |  | (5.8) | 0.0 |
Goodwill impairment |  | 318.3 |  |  | 0.0 |
Impairment of intangible assets |  |  |  | 59.9 | 9.6 |
Impairment of long-lived assets held and used |  |  |  | 5.8 | 0.0 |
Impairment of right-of-use assets |  |  |  | 0.4 | 0.2 |
Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Goodwill | 457.5 |  | 0.0 | 457.5 | 0.0 |
Franchise rights and other | 26.2 |  | 8.9 | 26.2 | 8.9 |
Right-of-use assets | 1.4 |  | 0.1 | 1.4 | 0.1 |
Long-lived assets held and used | 1.8 |  | 0.0 | 1.8 | 0.0 |
Continuing Operations [Member] | Fair Value, Nonrecurring [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Gain/(Loss) on assets held for sale |  |  |  | 0.0 | (1.1) |
Impairment of assets held for sale |  |  |  | 0.0 | 1.1 |
Continuing Operations [Member] | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Long-lived assets held for sale in continuing operations | 0.0 |  | $ 21.3 | 0.0 | 21.3 |
Reported Value Measurement [Member] | Continuing Operations [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Assets held for sale | 37.6 |  |  | 37.6 |  | $ 40.6
Reported Value Measurement [Member] | Discontinued Operations [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Assets held for sale in discontinued operations | 8.0 |  |  | 8.0 |  | $ 8.0
Franchise Rights [Member] | Fair Value, Nonrecurring [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Franchise rights impairment | $ 0.0 | 57.5 |  |  | $ 9.6 |
Reporting Unit, Premium Luxury [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Gain/(Loss) on goodwill |  |  |  | (257.4) |  |
Goodwill impairment |  |  |  | 257.4 |  |
Reporting Unit, Premium Luxury [Member] | Fair Value, Nonrecurring [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Gain/(Loss) on goodwill |  | (257.4) |  |  |  |
Goodwill impairment |  | 257.4 |  |  |  |
Reporting Unit, Collision Centers [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Gain/(Loss) on goodwill |  |  |  | (41.6) |  |
Goodwill impairment |  |  |  | 41.6 |  |
Reporting Unit, Collision Centers [Member] | Fair Value, Nonrecurring [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Gain/(Loss) on goodwill |  | (41.6) |  |  |  |
Goodwill impairment |  | 41.6 |  |  |  |
Reporting Unit, Parts Centers [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Gain/(Loss) on goodwill |  |  |  | (19.3) |  |
Goodwill impairment |  |  |  | $ 19.3 |  |
Reporting Unit, Parts Centers [Member] | Fair Value, Nonrecurring [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Gain/(Loss) on goodwill |  | (19.3) |  |  |  |
Goodwill impairment |  | 19.3 |  |  |  |
Other Intangible Assets [Member] | Fair Value, Nonrecurring [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Gain/(Loss) on franchise rights and other |  | (2.4) |  |  |  |
Impairment of intangible assets |  | 2.4 |  |  |  |
Valuation Technique, Discounted Cash Flow [Member] | Franchise Rights [Member] | Fair Value, Nonrecurring [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Franchise rights and other |  | $ 24.6 |  |  |  |
Valuation Technique, Discounted Cash Flow [Member] | Franchise Rights [Member] | Fair Value, Nonrecurring [Member] | Measurement Input, Long-term Revenue Growth Rate [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Franchise rights, measurement input |  | 0.020 |  |  |  |
Valuation Technique, Discounted Cash Flow [Member] | Minimum [Member] | Franchise Rights [Member] | Fair Value, Nonrecurring [Member] | Measurement Input, Discount Rate [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Franchise rights, measurement input |  | 0.111 |  |  |  |
Valuation Technique, Discounted Cash Flow [Member] | Minimum [Member] | Franchise Rights [Member] | Fair Value, Nonrecurring [Member] | Measurement Input, Long-term Pretax Income Margin [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Franchise rights, measurement input |  | 0.006 |  |  |  |
Valuation Technique, Discounted Cash Flow [Member] | Minimum [Member] | Franchise Rights [Member] | Fair Value, Nonrecurring [Member] | Measurement Input, Contributory Asset Charges [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Franchise rights, measurement input |  | 0.042 |  |  |  |
Valuation Technique, Discounted Cash Flow [Member] | Maximum [Member] | Franchise Rights [Member] | Fair Value, Nonrecurring [Member] | Measurement Input, Discount Rate [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Franchise rights, measurement input |  | 0.143 |  |  |  |
Valuation Technique, Discounted Cash Flow [Member] | Maximum [Member] | Franchise Rights [Member] | Fair Value, Nonrecurring [Member] | Measurement Input, Long-term Pretax Income Margin [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Franchise rights, measurement input |  | 0.028 |  |  |  |
Valuation Technique, Discounted Cash Flow [Member] | Maximum [Member] | Franchise Rights [Member] | Fair Value, Nonrecurring [Member] | Measurement Input, Contributory Asset Charges [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Franchise rights, measurement input |  | 0.121 |  |  |  |
Valuation Technique, Discounted Cash Flow [Member] | Weighted Average [Member] | Franchise Rights [Member] | Fair Value, Nonrecurring [Member] | Measurement Input, Weighted Average Cost of Capital [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Franchise rights, measurement input |  | 0.085 |  |  |  |
Valuation Technique, Discounted Cash Flow [Member] | Weighted Average [Member] | Franchise Rights [Member] | Fair Value, Nonrecurring [Member] | Measurement Input, Discount Rate [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Franchise rights, measurement input |  | 0.121 |  |  |  |
Valuation Technique, Discounted Cash Flow [Member] | Weighted Average [Member] | Franchise Rights [Member] | Fair Value, Nonrecurring [Member] | Measurement Input, Long-term Pretax Income Margin [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Franchise rights, measurement input |  | 0.014 |  |  |  |
Valuation Technique, Discounted Cash Flow [Member] | Weighted Average [Member] | Franchise Rights [Member] | Fair Value, Nonrecurring [Member] | Measurement Input, Contributory Asset Charges [Member] | Fair Value, Inputs, Level 3 [Member] |  |  |  |  |  |
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] |  |  |  |  |  |
Franchise rights, measurement input |  | 0.062 |  |  |  |

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