Reclassifications from Accumulated Other Comprehensive Loss - Schedule of Amounts Reclassified from AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2023
Amount reclassified from AOCI
Other expense, net	$ (6.1)	$ (60.5)	$ (6.5)
Income before income taxes	467.3	211.6	72.5
Tax benefit (expense)	(91.3)	(25.1)	(16.1)
Net income	376.0	186.5	$ 56.4
Amount Reclassified from AOCI | Cash flow hedging items
Amount reclassified from AOCI
Cost of sales	(4.2)	(11.0)
Income before income taxes	(4.2)	(11.0)
Tax benefit (expense)	1.0	2.6
Net income	(3.2)	(8.4)
Amount Reclassified from AOCI | Pension and other postretirement benefit plan items
Amount reclassified from AOCI
Income before income taxes	(5.0)	(55.6)
Tax benefit (expense)	1.2	13.2
Net income	(3.8)	(42.4)
Amount Reclassified from AOCI | Net actuarial loss
Amount reclassified from AOCI
Other expense, net	(1.7)	(5.5)
Amount Reclassified from AOCI | Prior service (cost) benefit
Amount reclassified from AOCI
Other expense, net	(3.3)	1.8
Amount Reclassified from AOCI | Settlement charge
Amount reclassified from AOCI
Other expense, net	$ 0.0	$ (51.9)