Accumulated Other Comprehensive Income (Loss) Reclassification Adjustments (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Interest Expense	$ 49.7	$ 48.3	$ 98.4	$ 96.3
Total reclassifications for the period	0.9	3.1	3.0	14.4
Reclassification out of Accumulated Other Comprehensive Income [Member]
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	1.2	2.3	3.8	9.1
Accumulated Net Gain (Loss) from Interest Rate Hedge [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Interest Expense	$ 0.3	$ (0.8)	$ 0.8	$ (5.3)