Retirement Benefits (Amounts Recognized on Balance Sheet) (Details) - USD ($) $ in Millions	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	$ 133.9	$ 219.2
Accrued liabilities	11.1	25.6
Defined Benefit Pension Plan | U.S.
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	36.4	90.5
Accrued liabilities	5.8	19.6
Noncurrent liabilities	77.4	62.5
Net Asset (Liability) Recognized	(46.8)	8.4
Defined Benefit Pension Plan | International
Defined Benefit Plan Disclosure [Line Items]
Noncurrent assets	97.5	128.7
Accrued liabilities	0.4	0.5
Noncurrent liabilities	112.6	192.8
Net Asset (Liability) Recognized	$ (15.5)	$ (64.6)