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Quarterly Financial Data (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended | 12 Months Ended | 28 Months Ended
--- | --- | --- | ---
Sep. 30, 2020 | Jun. 30, 2020 | Mar. 31, 2020 | Dec. 31, 2019 | Jun. 30, 2019 | Mar. 31, 2019 | Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2020
Quarterly Financial Data [Line Items] |  |  |  |  |  |  |  |  |  |
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down |  |  |  |  |  |  | $ 412.4 |  |  |
Proceeds From Insurance Settlement |  |  |  |  | $ 297.0 | $ 108.0 |  |  |  | $ 800.0
Loss on early extinguishment of long-term debt | $ 243.4 |  |  |  |  |  | $ (243.5) | $ 0.0 | $ (45.5) |
Columbia Of Massachusetts |  |  |  |  |  |  |  |  |  |
Quarterly Financial Data [Line Items] |  |  |  |  |  |  |  |  |  |
Disposal Group, Not Discontinued Operation, Loss (Gain) on Write-down |  | $ 84.4 | $ 280.2 |  |  |  |  |  |  |
Goodwill, Impairment Loss |  |  |  | $ 204.8 |  |  |  |  |  |
Impairment of Intangible Assets, Finite-lived |  |  |  | $ 209.7 |  |  |  |  |  |

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- Definition Amount, before tax, of (gain) loss recognized for the (reversal of write-down) write-down to fair value, less cost to sell, of a disposal group. Excludes discontinued operations. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=109226691&loc=d3e2941-110230 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3602-108585 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 360 -SubTopic 10 -Section 45 -Paragraph 5 -URI http://asc.fasb.org/extlink&oid=109226348&loc=d3e2443-110228 + Details
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