Employee Benefits - Accumulated Benefit Obligations (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 2,156.8	$ 2,279.6
Information for pension or OPEB plans with an accumulated benefit obligation in excess of plan assets
Accumulated benefit obligation	286.0	300.7
Fair value of plan assets	143.2	147.3
Information for pension plans with a projected benefit obligation in excess of plan assets
Projected benefit obligation	290.5	306.7
Fair value of plan assets	143.2	147.3
OPEB Benefits
Information for pension or OPEB plans with an accumulated benefit obligation in excess of plan assets
Accumulated benefit obligation	194.0	21.0
Fair value of plan assets	$ 177.0	$ 6.9