Retirement Benefits (Assumptions in Calculating Net Periodic Benefit Cost) (Details)	12 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2017
U.S.
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	7.00%
International
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	5.30%
Defined Benefit Pension Plan | U.S.
Defined Benefit Plan Disclosure [Line Items]
Discount rate – Service cost	4.30%	3.90%	3.60%
Discount rate – Interest cost	4.00%	3.30%	3.00%
Expected return on plan assets	7.00%	7.50%	8.00%
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	2.50%	2.60%	2.10%
Discount rate – Interest cost	2.20%	2.20%	1.80%
Expected return on plan assets	5.30%	5.80%	6.10%
Rate of compensation increase	3.50%	3.60%	3.50%