Retirement Benefits - Schedule of Significant Assumptions Used in Determining Benefit Obligations (Details)	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Expected gross health care cost trend rate	5.00%
Pension Benefits \| U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	6.10%	5.65%	3.10%
Compensation increase rate	3.60%	3.30%
Health care cost trend rate	0.00%	0.00%
Pension Benefits \| Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.65%	4.35%
Compensation increase rate	3.24%	3.03%
Health care cost trend rate	0.00%	0.00%
Other Postretirement Benefits \| U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	6.20%	5.70%
Compensation increase rate	0.00%	0.00%
Health care cost trend rate	6.50%	6.50%
Expected gross health care cost trend rate	0.00%
Other Postretirement Benefits \| Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Discount rate	5.75%	5.10%
Compensation increase rate	0.00%	0.00%
Health care cost trend rate	4.50%	4.50%

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

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- Definition

Weighted average rate increase of compensation, used to determine benefit obligation of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (k)(2)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

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Assumed rate, for next fiscal year, based on annual change in cost of health care cost benefits used to measure expected cost of benefits covered by defined benefit postretirement plan. Factors include, but are not limited to, estimate of health care inflation, change in health care utilization or delivery pattern, technological advances, and change in health status of participant. Excludes factors for change in composition of plan population by age and dependency status.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (l)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

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- Definition

Ultimate trend rate for health care cost for defined benefit postretirement plan.

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