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Goodwill and Intangible Assets, Net (Goodwill) (Details) - USD ($) $ in Millions | 12 Months Ended |
--- | --- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Goodwill [Roll Forward] |  |  |  |
Goodwill, beginning balance | [1] | $ 1,513.2 | $ 1,515.0 |
Acquisitions, dispositions, and other adjustments, net | [2] | (11.3) | (1.8) |
Goodwill, ending balance | [1] | 1,501.9 | 1,513.2 |
Accumulated impairment losses |  | 1,470.0 | 1,470.0 | $ 1,470.0
Reporting Unit, Domestic [Member] |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Goodwill, beginning balance | [1] | 232.5 | 231.7 |
Acquisitions, dispositions, and other adjustments, net | [2] | (5.2) | 0.8 |
Goodwill, ending balance | [1] | 227.3 | 232.5 |
Accumulated impairment losses |  | 140.0 | 140.0 | $ 140.0
Reporting Unit, Import [Member] |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Goodwill, beginning balance | [1] | 520.9 | 532.4 |
Acquisitions, dispositions, and other adjustments, net | [2] | (22.0) | (11.5) |
Goodwill, ending balance | [1] | 498.9 | 520.9 |
Reporting Unit, Premium Luxury [Member] |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Goodwill, beginning balance | [1] | 717.7 | 712.1 |
Acquisitions, dispositions, and other adjustments, net | [2] | (2.8) | 5.6 |
Goodwill, ending balance | [1] | 714.9 | 717.7 |
Reporting Unit, Collision Centers [Member] |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Goodwill, beginning balance | [1] | 42.1 | 38.8 |
Acquisitions, dispositions, and other adjustments, net | [2] | (0.4) | 3.3 |
Goodwill, ending balance | [1] | 41.7 | 42.1 |
Reporting Unit, Parts Distribution Centers [Member] |  |  |  |
Goodwill [Roll Forward] |  |  |  |
Goodwill, beginning balance | [1] | 0.0 | 0.0 |
Acquisitions, dispositions, and other adjustments, net | [2] | 19.1 | 0.0 |
Goodwill, ending balance | [1] | $ 19.1 | $ 0.0 |
[1] | Net of accumulated impairment losses of $1.47 billion associated with our single reporting unit (prior to September 30, 2008, our reporting unit structure was comprised of a single reporting unit) and $140.0 million associated with our Domestic reporting unit, both of which were recorded during the year ended December 31, 2008.
[2] | Includes amounts reclassified to held for sale and related adjustments, which are presented in Other Current Assets in our Consolidated Balance Sheet as of period end.

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