Retirement Benefits - Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Contributions by employer		$ 2.6
Actuarial loss	$ 9.7
Deferred pension cost (reversal of cost)	10.7
Increase in plan assets	$ 1.0
Other current assets
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, assets		4.4
Pension Benefits
Defined Benefit Plan Disclosure [Line Items]
Expected contribution for next fiscal year		4.0
Other Postretirement Benefits
Defined Benefit Plan Disclosure [Line Items]
Expected contribution for next fiscal year		$ 1.2