Pension Plans and Other Postretirement Benefits - Net Amounts Recognized (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022	Dec. 31, 2021
Net amounts recognized in the balance sheets at December 31
Benefit obligations	$ 237.8	$ 237.8	$ 274.7
Cash contributions and benefit payments to unfunded plans	1.4	6.1
Additional cash contributions, including benefit payments to unfunded plans	$ 2.7	$ 2.7