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Pension And Other Post-Retirement Benefits (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | ---
Mar. 31, 2020 | Sep. 30, 2020 | Dec. 31, 2020 | Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position |  | $ (105.3) |  | $ (108.1)
Other Post-Retirement Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Contribution to pension plans for continuing operations | $ 0.3 |  |  |
Pension Benefits |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Expected required contributions |  |  | $ 12.3 |
Contribution to pension plans for continuing operations |  | 1.8 |  |
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year |  |  | $ 7.9 |
Accrued Expenses [Member] |  |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |  |
Liability, Defined Benefit Plan, Current |  | $ 0.7 |  |

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