Commitments And Contingencies (Details) $ in Millions	6 Months Ended
Mar. 31, 2023 USD ($)
Commitments and Contingencies [Line Items]
Estimated minimum liability for environmental remediation	$ 3.8
Project Costs	$ 55.9
Less Than One Year [Member]
Commitments and Contingencies [Line Items]
Rate recovery period	1 year

Project costs included within Property, Plant and Equipment and Deferred Charges on the Consolidated Balance Sheet

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- Definition

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

No definition available.

+ Details

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- Definition

Reflects the estimated amount of loss from the specified contingency as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
-Section 50
-Paragraph 2
-URI https://asc.fasb.org/extlink&oid=124440162&loc=d3e12021-110248

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- Definition

Remaining recovery period of regulatory assets for which no return on investment during recovery period is provided, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 340
-Section 55
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