Pension and Other Postretirement Benefits - Schedule of Amounts Recognized in the Consolidated Balance Sheets (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024
Pension Benefits
Amounts recognized in accumulated other comprehensive loss:
Net actuarial loss (gain)	$ 198.9	$ 215.4
Prior service cost	2.1	4.2
Total	201.0	219.6
Other changes in plan assets and benefit obligations recognized in other comprehensive income consist of:
Net actuarial (gain) loss	(9.2)	15.5
Amortization of net (loss) gain	(7.3)	(8.0)
Amortization of prior service (cost) benefit	(2.1)	(2.1)
Settlement charge	0.0	(51.9)
Total, before tax effect	(18.6)	(46.5)
Additional information:
Accumulated benefit obligation for all pension plans	674.2	678.5
Other Benefits
Amounts recognized in accumulated other comprehensive loss:
Net actuarial loss (gain)	(66.8)	(64.3)
Prior service cost	0.3	1.5
Total	(66.5)	(62.8)
Other changes in plan assets and benefit obligations recognized in other comprehensive income consist of:
Net actuarial (gain) loss	(8.1)	(27.2)
Amortization of net (loss) gain	5.6	2.5
Amortization of prior service (cost) benefit	(1.2)	3.9
Settlement charge	0.0	0.0
Total, before tax effect	$ (3.7)	$ (20.8)