Accumulated Other Comprehensive Income (Loss) Reclassification Adjustments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Interest Expense	$ 48.7	$ 48.0
Total reclassifications for the period	2.1	11.3
Reclassification out of Accumulated Other Comprehensive Income [Member]
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	2.6	6.8
Accumulated Net Gain (Loss) from Interest Rate Hedge [Member] | Reclassification out of Accumulated Other Comprehensive Income [Member]
Interest Expense	$ 0.5	$ (4.5)