Employee Benefits - Accumulated Benefit Obligations (Details) - USD ($) $ in Millions	Dec. 31, 2022	Dec. 31, 2021
Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Accumulated benefit obligation	$ 2,250.6	$ 3,010.5
Information for pension or OPEB plans with an accumulated benefit obligation in excess of plan assets
Accumulated benefit obligation	185.7	372.4
Fair value of plan assets	32.8	186.3
Information for pension plans with a projected benefit obligation in excess of plan assets
Projected benefit obligation	191.3	383.0
Fair value of plan assets	32.8	186.3
OPEB Benefits
Information for pension or OPEB plans with an accumulated benefit obligation in excess of plan assets
Accumulated benefit obligation	20.6	25.1
Fair value of plan assets	$ 7.4	$ 2.8