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Pension And Other Postretirement Benefits (Narrative) (Details) - USD ($)
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
Defined Benefit Plan Disclosure [Line Items]        
Regulatory Assets $ 5.7   $ 5.7  
Postemployment Benefits [Abstract]        
Regulatory Liabilities $ 23.3   23.3  
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Remeasurement due to Settlement     $ 5.6  
Defined Benefit Plan, Ultimate Health Care Cost Trend Rate 475.00%   475.00%  
Defined Benefit Plan, Assumed Health Care Cost Trend Rate, Description     9.97  
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Change Due to Subsequent Interim Measurement, Weighted-Average Expected Long-Term Rate of Return on Plan Assets     688.00%  
Discount rate 553.00%   553.00%  
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement     $ 1.7  
Other Comprehensive Income (Loss), Defined Benefit Plan, Settlement and Curtailment Gain (Loss), before Tax     17.6  
Pension Plan        
Defined Benefit Plan Disclosure [Line Items]        
Employer contributions     1,500,000 $ 1,900,000
Postemployment Benefits [Abstract]        
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement $ (5,600,000) $ (5,900,000) (5,600,000) (5,900,000)
Defined Benefit Plan, Expected Return (Loss) on Plan Assets 23,100,000 23,800,000 69,300,000 71,400,000
Other Postretirement Benefit Plan        
Defined Benefit Plan Disclosure [Line Items]        
Employer contributions     15,400,000 18,300,000
Postemployment Benefits [Abstract]        
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement 0 0   0
Defined Benefit Plan, Expected Return (Loss) on Plan Assets $ 4,200,000 $ 4,000,000.0 $ 12,600,000 $ 12,000,000.0