Other Postretirement Benefit Plans (Details) - Postretirement Plan - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Interest cost	$ 0.4	$ 0.4
Amortization of prior service credit	(2.5)	(2.5)
Net periodic benefit cost (credit)	$ (2.1)	$ (2.1)