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Pension And Other Postretirement Benefits (Narrative) (Details) $ in Millions | 3 Months Ended
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Mar. 31, 2021 USD ($)
Pension Plan |
Defined Benefit Plan Disclosure [Line Items] |
Employer contributions | $ 0.7
Defined Benefit Plan, Pension Asset, (Increase)Decrease For Remeasurement Due To Settlement | (5.8)
Change in Regulatory Assets Due to Interim Measurement | 2.1
Change in Accumulated Other Comprehensive Income Due to Interim Measurement | 0.4
Change to Defined Benefit Plan Net Periodic Costs Due to Interim Measurement | 4.0
Other Postretirement Benefit Plan |
Defined Benefit Plan Disclosure [Line Items] |
Employer contributions | $ 5.1

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