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Employee Benefits - Summary of Components of Net Periodic Postretirement Benefit Cost (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2025
Mar. 31, 2024
Defined Benefit Plan Disclosure [Line Items]    
Total net periodic postretirement and postemployment benefit cost (credit) $ 1.2 $ 0.3
Pension Plans    
Defined Benefit Plan Disclosure [Line Items]    
Service cost 0.9 0.9
Interest cost 0.4 0.4
Expected return on plan assets (0.4) (0.3)
Amortization of prior service cost (credit) 0.2 0.2
Total net periodic postretirement and postemployment benefit cost (credit) 1.1 1.2
Other Postretirement Benefits Plan    
Defined Benefit Plan Disclosure [Line Items]    
Service cost 0.2 0.3
Interest cost 0.9 0.8
Amortization of net actuarial gain (0.5) (0.3)
Total net periodic postretirement and postemployment benefit cost (credit) 0.6 0.8
Postretirement Health Coverage | Salaried VEBA    
Defined Benefit Plan Disclosure [Line Items]    
Interest cost 0.5 0.5
Expected return on plan assets (0.5) (0.5)
Amortization of prior service cost (credit) 0.7 (0.5)
Amortization of net actuarial gain (0.1)  
Total net periodic postretirement and postemployment benefit cost (credit) $ 0.6 $ (0.5)