Reclassifications from Accumulated Other Comprehensive Loss - Schedule of Amounts Reclassified from AOCI (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2024	Mar. 31, 2023	Mar. 31, 2024	Mar. 31, 2023
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other	$ 0.0	$ 0.0	$ (0.1)	$ 0.1
Total before tax	10.1	24.0	117.7	23.9
Tax benefit (expense)	(3.8)	(5.4)	(24.8)	(5.9)
Net income	6.3	18.6	92.9	18.0
Amount Reclassified from AOCI | Cash flow hedging items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	(4.2)	1.0	(7.4)	8.9
Tax benefit (expense)	1.0	(0.2)	1.7	(2.2)
Net income	(3.2)	0.8	(5.7)	6.7
Amount Reclassified from AOCI | Settlement charge
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other	(51.9)	0.0	(51.9)	0.0
Amount Reclassified from AOCI | Pension and other postretirement benefit plan items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Total before tax	(52.7)	(1.5)	(54.9)	(4.5)
Tax benefit (expense)	12.5	0.4	13.1	1.3
Net income	(40.2)	(1.1)	(41.8)	(3.2)
Amount Reclassified from AOCI | Net actuarial loss
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other	(1.3)	(2.0)	(4.3)	(6.0)
Amount Reclassified from AOCI | Prior service benefit
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Other	0.5	0.5	1.3	1.5
Commodity contracts | Amount Reclassified from AOCI | Cash flow hedging items
Reclassification Adjustment out of Accumulated Other Comprehensive Income [Line Items]
Cost of sales	$ (4.2)	$ 1.0	$ (7.4)	$ 8.9