Pension Benefits and Postretirement Benefits Other Than Pensions - Pension Income (Details) - Pension Plans - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Defined Benefit Plan Disclosure [Line Items]
Interest Cost on Projected Benefit Obligation	$ 1.8	$ 4.5	$ 5.3	$ 13.5
Expected Return on Plan Assets	(2.3)	(7.3)	(7.0)	(22.0)
Amortization of Net Actuarial Loss	0.7	1.6	2.2	4.6
Total Pension (Benefit) Expense	$ 0.2	$ (1.2)	$ 0.5	$ (3.9)