v3.26.1
Pension and Other Postretirement Benefits - Summary of Components of Net Periodic Benefit Cost (Details) - USD ($)
$ in Millions
 12 Months Ended
Jun. 30, 2026
Jun. 30, 2025
Jun. 30, 2024
Defined Benefit Plan Disclosure [Line Items]      
Settlement charge $ 0.3 $ 0.0 $ 51.9
Pension Benefits      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 6.9 7.9 8.2
Interest cost 37.6 38.7 43.7
Expected return on plan assets (34.6) (29.7) (35.9)
Amortization of net loss (gain) 6.6 7.3 8.0
Amortization of prior service cost (benefit) 1.5 2.1 2.1
Settlement charge 0.3 0.0 51.9
Net pension expense (income) 18.3 26.3 78.0
Other Postretirement Plans      
Defined Benefit Plan Disclosure [Line Items]      
Service cost 1.4 1.4 1.5
Interest cost 9.5 9.9 10.2
Expected return on plan assets (8.9) (8.4) (7.3)
Amortization of net loss (gain) (5.9) (5.6) (2.5)
Amortization of prior service cost (benefit) 0.2 1.2 (3.9)
Settlement charge 0.0 0.0 0.0
Net pension expense (income) $ (3.7) $ (1.5) $ (2.0)