Income Taxes (Schedule of Income Tax Expense (Benefit)) (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Mar. 31, 2020	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2019
Current
Federal		$ 77.3	$ 18.7	$ (29.8)
State		16.9	7.9	(2.8)
Foreign		1.2	1.1	0.6
Current		95.4	27.7	(32.0)
Deferred
Federal		(6.5)	(42.6)	42.0
State		(2.0)	(17.5)	1.6
Foreign		0.1	0.2	(0.1)
Deferred		(8.4)	(59.9)	43.5
Income tax expense (benefit)	$ (26.9)	$ 87.0	$ (32.2)	$ 11.5