Derivative Instruments and Hedging Activities (Gains or Losses Recognized in AOCI for the Cash Flow Hedges) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax	$ 11.2	$ 12.0	$ 12.8
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax	(0.8)	(0.8)	(0.8)
Interest Rate Contract [Member]
Portion expected to be reclassified to earnings in the next twelve months	$ (0.8)
AOCI, Cash Flow Hedge, Cumulative Gain (Loss), after Tax		$ 12.0	$ 12.8	$ 13.6