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Pension and Postretirement Health and Life Benefits (Schedule of Net Benefit Costs) (Details) - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Sep. 30, 2025
Sep. 30, 2024
Sep. 30, 2025
Sep. 30, 2024
May 28, 2024
Defined Benefit Plan, Net Periodic Benefit Cost (Credit), Gain (Loss) Due to Settlement and Curtailment $ 0.0 $ (0.2) $ 0.0 $ (16.8)  
Defined Benefit Plan, Pension Plan Obligations Transferred   15.4   15.4 $ 234.0
Defined Benefit Plan, Pension Plan Assets Transferred         $ 224.0
Pension Plan, Defined Benefit [Member]          
Service costs 0.1 0.5 0.3 1.5  
Interest costs 0.4 0.2 1.2 7.8  
Amortization of prior service costs (credits), net 0.0 0.1 (0.1) 0.0  
Expected return on plan assets (gains) (0.5) (0.2) (1.4) (9.5)  
Net periodic benefit cost (credit) 0.0 0.4 0.0 (17.0)  
Postretirement Health and Life Benefits Plans [Member]          
Interest costs 1.2 1.2 3.4 3.4  
Amortization of prior service costs (credits), net (0.1) (0.1) (0.1) (0.1)  
Net periodic benefit cost (credit) $ 1.1 $ 1.1 $ 3.3 $ 3.3