Other Expense, Net (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Other Income And Expenses [Abstract]
Interest income	$ 0.2	$ 0.6	$ 0.6
Net periodic postretirement benefit cost	(4.1)	(4.7)	(6.5)
Realized gain on available for sale securities		2.0	4.4
Unrealized (loss) gain on equity securities	(0.2)	0.7	0.7
(Loss) gain on extinguishment of debt – Note 9	(35.9)		(20.3)
All other, net	1.1		0.4
Other expense, net	$ (38.9)	$ (1.4)	$ (20.7)