Other Income/(Expense), Net (Schedule of Other Income/(Expense), Net) (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 31, 2021	Aug. 31, 2020
Other Income/(Expense), Net [Abstract]
Interest income on corporate investments	$ 0.2	$ 0.6
Interest expense	(9.2)	(9.0)
Other	10.0	0.5
Other income/(expense), net	$ 1.0	$ (7.9)