Non-operating Income (Expense) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Nonoperating Income (Expense) [Abstract]
Interest Expense	$ (11.7)	$ (12.8)	$ (35.4)	$ (37.4)
Amortization of Debt Issuance Costs	(0.5)	(0.5)	(1.7)	(1.5)
Interest Income, Other	0.0	0.0	0.0	0.7
Interest Expense, Net	(12.2)	(13.1)	(37.0)	(32.5)
Net Periodic Defined Benefits Expense (Reversal of Expense), Excluding Service Cost Component	(1.9)	(1.4)	(5.7)	(4.3)
Nonoperating Income (Expense)	(17.9)	(17.2)	(47.5)	(39.5)
Interest Costs Capitalized Adjustment	0.0	0.3	0.0	5.7
Term Loan [Member]
Nonoperating Income (Expense) [Abstract]
Write off of Deferred Debt Issuance Cost	3.9	2.7	4.8	2.7
Write off of Deferred Debt Issuance Cost	$ 3.9	$ 2.7	$ 4.8	$ 2.7