Derivative Financial Instruments (Amounts Included in AOCL) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Derivative Losses Included in AOCL
Beginning balance	$ 1,899.8	$ 2,303.8	$ 2,715.0
Net loss on cash flow hedges	0.0	0.0	(9.5)
Reclassification of net loss on cash flow hedges to income	3.5	3.5	3.5
Ending balance	1,684.9	1,899.8	2,303.8
Derivative Losses Included in AOCL
Derivative Losses Included in AOCL
Beginning balance	(51.5)	(55.0)	(49.0)
Ending balance	$ (48.0)	$ (51.5)	$ (55.0)