Retirement Benefits (Assumptions in Calculating Net Periodic Benefit Cost) (Details)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
U.S.
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	5.80%
International
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	4.20%
Defined Benefit Pension Plan | U.S.
Defined Benefit Plan Disclosure [Line Items]
Discount rate – Service cost	5.70%	3.00%	3.00%
Discount rate – Interest cost	5.50%	2.30%	2.10%
Expected return on plan assets	5.80%	5.80%	6.80%
Rate of compensation increase	3.50%	3.50%	3.50%
Defined Benefit Pension Plan | International
Defined Benefit Plan Disclosure [Line Items]
Discount rate – Service cost	4.60%	1.90%	1.60%
Discount rate – Interest cost	5.00%	1.60%	1.20%
Expected return on plan assets	4.20%	4.00%	4.70%
Rate of compensation increase	3.40%	3.30%	3.30%