Pension and Other Postretirement Benefits - Schedule of Amounts Recognized in the Consolidated Balance Sheets (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Pension Benefits
Amounts recognized in accumulated other comprehensive loss (income):
Net actuarial loss	$ 298.0	$ 487.2
Prior service cost (credit)	10.0	12.0
Total	308.0	499.2
Other changes in plan assets and benefit obligations recognized in other comprehensive loss consist of:
Net actuarial (gain) loss	(162.6)	56.9
Amortization of net loss	(15.3)	(15.5)
Amortization of prior service (cost) benefit	(2.1)	(2.1)
Settlement charge	(11.4)	0.0
Total, before tax effect	(191.4)	39.3
Additional information:
Accumulated benefit obligation for all pension plans	1,217.6	1,335.2
Other Benefits
Amounts recognized in accumulated other comprehensive loss (income):
Net actuarial loss	10.3	53.3
Prior service cost (credit)	(10.1)	(14.0)
Total	0.2	39.3
Other changes in plan assets and benefit obligations recognized in other comprehensive loss consist of:
Net actuarial (gain) loss	(39.4)	13.5
Amortization of net loss	(3.6)	(2.5)
Amortization of prior service (cost) benefit	3.9	3.9
Settlement charge	0.0	0.0
Total, before tax effect	$ (39.1)	$ 14.9