v3.25.2
Pension Plans - Schedule of Net Benefit Costs (Details) - Pension Plan - USD ($)
$ in Millions
 3 Months Ended 9 Months Ended
Jun. 30, 2025
Jun. 30, 2024
Jun. 30, 2025
Jun. 30, 2024
U.S.        
Defined Benefit Plan Disclosure [Line Items]        
Service cost $ 0.0 $ 0.0 $ 0.0 $ 0.0
Interest cost 3.0 3.7 9.1 10.9
Expected return on plan assets (4.0) (3.2) (11.9) (9.8)
Amortization of unrecognized net losses 0.5 0.5 1.4 1.4
Net periodic (benefit)/cost (0.5) 1.0 (1.4) 2.5
International        
Defined Benefit Plan Disclosure [Line Items]        
Service cost 0.2 0.1 0.4 0.3
Interest cost 0.9 0.9 2.5 2.6
Expected return on plan assets (0.9) (1.0) (2.6) (2.7)
Amortization of unrecognized net losses 0.5 0.2 1.5 0.7
Net periodic (benefit)/cost $ 0.7 $ 0.2 $ 1.8 $ 0.9