Pension Benefit Obligations - Schedule of Additional Year-End Information for Pension Plans With Accumulated Benefit Obligations In Excess of Plan Assets (Details) - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2023
U.S.
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	$ 165.8	$ 175.1	$ 168.8
Accumulated benefit obligation	165.8	175.1	168.8
Fair value of plan assets	104.9	109.0	98.8
Int’l
Defined Benefit Plan Disclosure [Line Items]
Projected benefit obligation	395.6	649.8	628.1
Accumulated benefit obligation	395.6	649.8	628.1
Fair value of plan assets	$ 325.9	$ 547.1	$ 506.5