Income Taxes (Details 1) - USD ($) $ in Millions	12 Months Ended
	Apr. 30, 2021	Apr. 30, 2020	Apr. 30, 2019
Current:
Federal	$ 251.3	$ 188.7	$ 227.9
Foreign	11.7	8.5	16.0
State and local	46.7	42.4	36.8
Deferred:
Federal	(3.3)	7.1	(73.6)
Foreign	(7.9)	0.6	(0.1)
State and local	(2.9)	(0.1)	(19.8)
Total income tax expense (benefit)	$ 295.6	$ 247.2	$ 187.2