Retirement Benefits (Schedule of Assumptions Used) (Details)	12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2016
Defined Benefit Pension Plan [Member] | UNITED STATES
Weighted-average assumptions to determine benefit obligation at September 30:
Discount rate	4.35%	3.80%	3.65%
Weighted-average assumptions to determine periodic benefit costs for years ending September 30:
Discount rate	3.80%	3.65%	4.39%
Long-term rate of return on plan assets	7.39%	7.38%	7.62%
Defined Benefit Pension Plan [Member] | JAPAN
Weighted-average assumptions to determine benefit obligation at September 30:
Discount rate	0.62%	0.58%	0.46%
Rate of compensation increase	2.00%	2.00%	2.02%
Weighted-average assumptions to determine periodic benefit costs for years ending September 30:
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate, Service Cost	0.72%	0.59%	1.27%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate, Interest Cost	0.38%	0.45%	0.59%
Rate of compensation increase	2.00%	2.02%	2.00%
Long-term rate of return on plan assets	2.50%	2.50%	3.00%
Defined Benefit Pension Plan [Member] | UNITED KINGDOM
Weighted-average assumptions to determine benefit obligation at September 30:
Discount rate	2.68%	2.56%	2.28%
Rate of compensation increase	3.60%	3.60%	3.40%
Weighted-average assumptions to determine periodic benefit costs for years ending September 30:
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate, Service Cost	2.58%	2.33%	3.86%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate, Interest Cost	2.36%	2.24%	3.63%
Rate of compensation increase	3.60%	3.40%	3.40%
Long-term rate of return on plan assets	4.75%	4.75%	5.00%
Defined Benefit Pension Plan [Member] | GERMANY
Weighted-average assumptions to determine benefit obligation at September 30:
Discount rate	1.87%
Rate of compensation increase	2.50%
Weighted-average assumptions to determine periodic benefit costs for years ending September 30:
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate, Service Cost	2.05%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate, Interest Cost	1.49%
Rate of compensation increase	2.50%
Other Postretirement Benefit Plans [Member]
Weighted-average assumptions to determine benefit obligation at September 30:
Discount rate	4.30%	3.78%	3.63%
Weighted-average assumptions to determine periodic benefit costs for years ending September 30:
Discount rate	3.80%	3.63%	4.01%