v3.26.1
Retirement Plans - Components of Net Periodic Benefit Cost (Credit) (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2026
Mar. 31, 2025
Defined Benefit Pension Plan    
Defined Benefit Plan Disclosure [Line Items]    
Service cost $ 3.6 $ 3.6
Interest cost 5.7 4.7
Expected return on assets (5.3) (4.8)
Net (gain) loss (0.2) 0.1
Prior service cost (credit) 0.1 0.1
Total benefit cost (credit) 3.9 3.7
Retiree Health Care Plan    
Defined Benefit Plan Disclosure [Line Items]    
Service cost 0.0 0.0
Interest cost 0.1 0.1
Expected return on assets 0.0 0.0
Net (gain) loss 0.0 0.0
Prior service cost (credit) (0.2) (0.2)
Total benefit cost (credit) $ (0.1) $ (0.1)