v3.26.1
Pension and Other Postretirement Benefits - Summary of Reconciliation of Benefit Obligations, Plan Assets and Funded Status of the Plans (Details) - USD ($)
$ in Millions
 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2024
Pension Benefits      
Change in projected benefit obligation:      
Projected benefit obligation at beginning of year $ 678.6 $ 682.7  
Service cost 6.9 7.9 $ 8.2
Interest cost 37.6 38.7 43.7
Benefits paid (65.0) (59.3)  
Actuarial (gain) loss (17.4) 9.1  
Other (0.8) (0.5)  
Projected benefit obligation at end of year 639.9 678.6 682.7
Change in plan assets:      
Fair value of plan assets at beginning of year 528.4 471.8  
Actual return 57.4 48.0  
Benefits paid (65.0) (59.3)  
Contributions 27.0 67.9  
Plan settlements (0.7) 0.0  
Fair value of plan assets at end of year 547.1 528.4 471.8
Funded status of the plans, (underfunded) (92.8) (150.2)  
Amounts recognized in the consolidated balance sheets:      
Other assets - noncurrent 0.0 0.0  
Accrued liabilities - current (3.2) (3.3)  
Accrued pension and postretirement benefits - noncurrent (89.6) (146.9)  
Amounts recognized in the consolidated balance sheets (92.8) (150.2)  
Other Postretirement Plans      
Change in projected benefit obligation:      
Projected benefit obligation at beginning of year 171.1 172.8  
Service cost 1.4 1.4 1.5
Interest cost 9.5 9.9 10.2
Benefits paid (13.9) (13.6)  
Actuarial (gain) loss (3.8) 0.6  
Other 0.0 0.0  
Projected benefit obligation at end of year 164.3 171.1 172.8
Change in plan assets:      
Fair value of plan assets at beginning of year 143.3 136.3  
Actual return 25.8 17.0  
Benefits paid (13.9) (13.6)  
Contributions 4.0 3.6  
Plan settlements 0.0 0.0  
Fair value of plan assets at end of year 159.2 143.3 $ 136.3
Funded status of the plans, (underfunded) (5.1) (27.8)  
Amounts recognized in the consolidated balance sheets:      
Other assets - noncurrent 19.2 0.0  
Accrued liabilities - current (2.1) (15.3)  
Accrued pension and postretirement benefits - noncurrent (22.2) (12.5)  
Amounts recognized in the consolidated balance sheets $ (5.1) $ (27.8)