Employee Benefits - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Retirement Plans
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	$ 0.5	$ 0.5
Interest cost	1.0	1.0
Expected return on plan assets	(1.1)	(1.0)
Amortization of unrecognized net loss	0.0	0.2
Settlement charge	0.3	0.1
Net periodic benefit cost (credit)	0.7	0.8
PBOP
Defined Benefit Plan, Net Periodic Benefit Cost (Credit) [Abstract]
Service cost	0.0	0.0
Interest cost	0.3	0.3
Expected return on plan assets	(0.7)	(0.6)
Amortization of unrecognized net loss	0.0	0.0
Settlement charge	0.0	0.0
Net periodic benefit cost (credit)	$ (0.4)	$ (0.3)