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Benefit Plans Asset Holdings (Details) - USD ($)	12 Months Ended
	Sep. 30, 2023	Sep. 30, 2022	Sep. 30, 2021
Defined Benefit Plan Disclosure
Target Allocation	100.00%
Plan Asset Allocations	100.00%	100.00%
Growth Assets
Defined Benefit Plan Disclosure
Target Allocation	17.00%
Plan Asset Allocations	22.00%	20.00%
Defensive growth assets
Defined Benefit Plan Disclosure
Target Allocation	30.00%
Plan Asset Allocations	33.00%	34.00%
Defensive Assets
Defined Benefit Plan Disclosure
Target Allocation	33.00%
Plan Asset Allocations	17.00%	18.00%
Inflation-sensitive Assets
Defined Benefit Plan Disclosure
Target Allocation	20.00%
Plan Asset Allocations	28.00%	28.00%
Other Post-retirement Benefits
Defined Benefit Plan Disclosure
Actuarial assumption COLA	$ 0.06	$ 0.035	$ 0.0113

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- Definition

Percentage of target investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 55
-Paragraph 17
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480482/715-20-55-17

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

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Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 715
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480506/715-20-50-1

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