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Concentrations of Credit Risk - Additional Information (Details) customer in Millions, $ in Millions | 12 Months Ended
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Sep. 30, 2020 USD ($) customer State counterparty
Concentration Risk [Line Items] |
Number of large counterparties for which credit risk is disclosed | counterparty | 5
Number of counterparties with investment-grade rating | counterparty | 4
Utility Companies And Their Marketing Affiliates |
Concentration Risk [Line Items] |
Accounts receivable | $ | $ 73.0
Five Largest Counterparties |
Concentration Risk [Line Items] |
Accounts receivable | $ | $ 35.7
Gas Utility |
Concentration Risk [Line Items] |
Number of customer serves | customer | 1.7
Number of state serves across multiple rate classes | State | 3

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- Definition Number of large counterparties in terms of net accounts receivable exposure for which credit risk is reported. + References No definition available. + Details
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- Definition Number of counterparties, investment-grade rated or owned by investment-grade rated integrated utilities. + References No definition available. + Details
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- Definition Number of customer serves. + References No definition available. + Details
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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 This item represents disclosure of all significant concentrations of credit risk or market risk arising from the subject financial instrument (as defined), whether from an individual counterparty or groups of counterparties. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03(5)) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(3)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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