Retirement Benefits (Amounts Recognized on Balance Sheet) (Details) - USD ($) $ in Millions	Sep. 30, 2025	Sep. 30, 2024
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	$ 210.9	$ 200.0
Accrued liabilities	15.8	11.3
Defined Benefit Pension Plan | U.S.
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	44.9	45.3
Accrued liabilities	9.8	7.3
Noncurrent liabilities	141.8	118.1
Net (Liability) Asset Recognized	(106.7)	(80.1)
Defined Benefit Pension Plan | International
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	166.0	154.7
Accrued liabilities	2.7	0.9
Noncurrent liabilities	124.3	118.0
Net (Liability) Asset Recognized	$ 39.0	$ 35.8