Regulatory Matters	6 Months Ended
Regulatory Matters	Mar. 31, 2022
Regulatory Assets and Liabilities, Other Disclosures [Abstract]
Regulatory Matters	Regulatory Matters New York Jurisdiction Distribution Corporation's current delivery rates in its New York jurisdiction were approved by the NYPSC in an order issued on April 20, 2017 with rates becoming effective May 1, 2017. The order provided for a return on equity of 8.7%, and directed the implementation of an earnings sharing mechanism to be in place beginning on April 1, 2018. On August 13, 2021, the NYPSC issued an order extending the date through which qualified pipeline replacement costs incurred by the Company can be recovered using the existing system modernization tracker for two years (until March 31, 2023). The extension is contingent on the Company not filing a base rate case that would result in new rates becoming effective prior to April 1, 2023. In response to the COVID-19 pandemic, various legislative actions and NYPSC Staff requests resulted in the Company suspending service terminations and disconnections for a period of time. All legislative prohibitions have expired and the Company has agreed to refrain from terminating residential customers (1) with a pending application for arrears payments through the Emergency Rental Assistance Program administered by the Office of Temporary Disability and (2) participating in the Company’s Statewide Low Income Program (EAP) through September 1, 2022. Pennsylvania Jurisdiction Distribution Corporation’s current delivery rates in its Pennsylvania jurisdiction were approved by the PaPUC on November 30, 2006 as part of a settlement agreement that became effective January 1, 2007. The rate settlement does not specify any requirement to file a future rate case. On July 22, 2021, Distribution Corporation filed a supplement to its current Pennsylvania tariff proposing to reduce base rates effective October 1, 2021 by $7.7 million in order to stop collecting other post-employment benefit (“OPEB”) expenses from customers, to begin to refund to customers overcollected OPEB expenses in the amount of $50.0 million, to suspend all regulatory accounting for OPEB expenses and record the cumulative amount of OPEB income previously deferred as a regulatory liability, and to make certain other adjustments to further reduce Distribution Corporation’s regulatory liability associated with OPEB expenses. The PaPUC issued an order approving this tariff supplement on September 15, 2021 and new rates went into effect on October 1, 2021. On September 21, 2021, a complaint was filed in the proceeding. While new rates, including associated refunds, went into effect on October 1, 2021, the Company decided to wait for resolution of the complaint before suspending regulatory accounting for OPEB expenses and recording the cumulative amount of OPEB income previously deferred as a regulatory liability in its consolidated financial statements. The PaPUC assigned the matter to an Administrative Law Judge who, on January 6, 2022, issued a Recommended Decision approving a settlement reached by parties to the complaint proceeding. Under the terms of the settlement, customer refunds of overcollected OPEB expenses increased from $50.0 million to $54.0 million. The Recommended Decision was approved by the PaPUC on February 24, 2022. Accordingly, the Company suspended regulatory accounting for OPEB expenses at that time and recorded an $18.5 million adjustment during the quarter ended March 31, 2022 to reduce its regulatory liability for previously deferred OPEB income amounts through September 30, 2021 and to increase Other Income (Deductions) on the consolidated financial statements by a like amount. The refunds specified in the tariff supplement will be funded entirely by grantor trust assets held by the Company, most of which are included in a fixed income mutual fund that is a component of Other Investments on the Company’s Consolidated Balance Sheet. With the elimination of OPEB expenses in base rates, Distribution Corporation will no longer fund the grantor trust or its VEBA trusts in its Pennsylvania jurisdiction. FERC Jurisdiction Supply Corporation’s 2020 rate settlement provides that no party may make a rate filing for new rates to be effective before February 1, 2024, except that Supply Corporation may file an NGA general Section 4 rate case to change rates if the corporate federal income tax rate is increased. If no case has been filed, Supply Corporation must file for rates to be effective February 1, 2025. Empire’s 2019 rate settlement provides that Empire must make a rate case filing no later than May 1, 2025.