Pension and Other Post-Retirement Benefits - Projected and Accumulated Benefit Obligations (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Defined Benefit Plan, Pension Plan with Project Benefit Obligation in Excess of Plan Assets [Abstract]
Projected benefit obligations	$ 48.5	$ 380.7
Fair value of plan assets	0.0	321.6
Pension plans with an accumulated benefit obligation in excess of plan assets
Accumulated benefit obligations	42.1	41.7
Fair value of plan assets	$ 0.0	$ 0.0