Regulatory Matters	6 Months Ended
Mar. 31, 2018
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. On July 28, 2017, Distribution Corporation filed an appeal with New York State Supreme Court, Albany County, seeking review of the Order. The appeal contends that portions of the Order should be invalidated because they fail to meet the applicable legal standard for agency decisions. On December 11, 2017, the appeal was transferred to the Supreme Court, Appellate Division, Third Department. The Company cannot predict the outcome of the appeal at this time. On December 29, 2017, the NYPSC issued an order instituting a proceeding to study the potential effects of the enactment of the 2017 Tax Reform Act on the tax expenses and liabilities of New York utilities, and the “regulatory treatment of any windfalls resulting from same in order to preserve the benefits for ratepayers.” In its order, the NYPSC stated that the effect of the 2017 Tax Reform Act on utilities’ taxation is likely to be material and complex and that the proceeding was needed to begin the process of addressing the impact on the State’s utilities and ratepayers. The order also declares that utilities are “put on notice that it is the [NYPSC]’s intent to ensure that net benefits accruing from the Tax Act are preserved for ratepayers, either through deferral accounting or another method, from the first day the Tax Act is put into effect. Utilities acting contrary to this intent do so at their own risk.” Pursuant to the order, a technical conference was held with the utilities in February 2018, and on March 29, 2018, the New York Department of Public Service Staff (Staff) issued a proposal for accounting and ratemaking treatment of the tax changes. Interested parties have been invited to comment on the Staff proposal, including whether and how to incorporate into utility rates any modifications necessary to reflect changes in federal tax law affecting utilities. Refer to Note 4 - Income Taxes for further discussion of the 2017 Tax Reform Act. Pennsylvania Jurisdiction Distribution Corporation’s Pennsylvania jurisdiction delivery rates are being charged to customers in accordance with a rate settlement approved by the PaPUC. The rate settlement does not specify any requirement to file a future rate case. By Secretarial Letter issued February 12, 2018, the PaPUC initiated a proceeding to determine the effects of the 2017 Tax Reform Act on the tax liabilities of PaPUC-regulated public utilities for 2018 and future years and the feasibility of reflecting such impacts on the rates charged to utility ratepayers. In connection with such letter, the PaPUC issued certain data requests to utilities regarding the 2017 Tax Reform Act, and Distribution Corporation filed responses in March 2018. On March 15, 2018, the PaPUC issued a Temporary Rates Order making Distribution Corporation’s rates (along with the rates of other Pennsylvania public utilities not presently in a general rate increase proceeding) temporary for a period of six months, which may be extended by the PaPUC for an additional six months. The order states that due to the decrease in federal tax rates associated with the 2017 Tax Reform Act, it appears that existing utility rates may be excessive and, therefore, no longer just and reasonable. The order states that the PaPUC is making rates temporary to maximize its authority to establish any negative surcharge, refund or other rate adjustment deemed to be necessary, just and reasonable to account for the tax rate reductions associated with the 2017 Tax Reform Act, and is consistent with the approach that the PaPUC took following federal tax reform in 1986. The order further states that the PaPUC anticipates that after further review and analysis of the responses to data requests, financial information and public comments, it will direct utilities to file appropriate tariffs to account for the tax reductions associated with the 2017 Tax Reform Act that became effective January 1, 2018. Refer to Note 4 - Income Taxes for further discussion of the 2017 Tax Reform Act. FERC Jurisdiction Supply Corporation currently has no active rate case on file. Supply Corporation's current rate settlement requires a rate case filing no later than December 31, 2019. Empire currently has no active rate case on file. Empire’s current rate settlement requires a rate case filing no later than July 1, 2021. On March 15, 2018, the FERC issued three documents regarding its plans to undertake review of the 2017 Tax Reform Act and its impact on pipelines: a Notice of Proposed Rulemaking which proposes to require pipelines to file a new form isolating the tax impact to each pipeline and also to make an election regarding the action the pipelines will take to address the lower tax rates, one of which is filing a Section 4 rate proceeding; a Policy Statement regarding the treatment of taxes by MLP entities; and a Notice of Inquiry regarding treatment of accumulated deferred income taxes and other tax issues associated with the 2017 Tax Reform Act. The Company cannot predict the outcome of any of these proceedings at this time. Refer to Note 4 - Income Taxes for further discussion of the 2017 Tax Reform Act.

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. On July 28, 2017, Distribution Corporation filed an appeal with New York State Supreme Court, Albany County, seeking review of the Order. The appeal contends that portions of the Order should be invalidated because they fail to meet the applicable legal standard for agency decisions. On December 11, 2017, the appeal was transferred to the Supreme Court, Appellate Division, Third Department. The Company cannot predict the outcome of the appeal at this time.

On December 29, 2017, the NYPSC issued an order instituting a proceeding to study the potential effects of the enactment of the 2017 Tax Reform Act on the tax expenses and liabilities of New York utilities, and the “regulatory treatment of any windfalls resulting from same in order to preserve the benefits for ratepayers.” In its order, the NYPSC stated that the effect of the 2017 Tax Reform Act on utilities’ taxation is likely to be material and complex and that the proceeding was needed to begin the process of addressing the impact on the State’s utilities and ratepayers. The order also declares that utilities are “put on notice that it is the [NYPSC]’s intent to ensure that net benefits accruing from the Tax Act are preserved for ratepayers, either through deferral accounting or another method, from the first day the Tax Act is put into effect. Utilities acting contrary to this intent do so at their own risk.” Pursuant to the order, a technical conference was held with the utilities in February 2018, and on March 29, 2018, the New York Department of Public Service Staff (Staff) issued a proposal for accounting and ratemaking treatment of the tax changes. Interested parties have been invited to comment on the Staff proposal, including whether and how to incorporate into utility rates any modifications necessary to reflect changes in federal tax law affecting utilities. Refer to Note 4 - Income Taxes for further discussion of the 2017 Tax Reform Act.

Pennsylvania Jurisdiction

Distribution Corporation’s Pennsylvania jurisdiction delivery rates are being charged to customers in accordance with a rate settlement approved by the PaPUC. The rate settlement does not specify any requirement to file a future rate case.

By Secretarial Letter issued February 12, 2018, the PaPUC initiated a proceeding to determine the effects of the 2017 Tax Reform Act on the tax liabilities of PaPUC-regulated public utilities for 2018 and future years and the feasibility of reflecting such impacts on the rates charged to utility ratepayers. In connection with such letter, the PaPUC issued certain data requests to utilities regarding the 2017 Tax Reform Act, and Distribution Corporation filed responses in March 2018. On March 15, 2018, the PaPUC issued a Temporary Rates Order making Distribution Corporation’s rates (along with the rates of other Pennsylvania public utilities not presently in a general rate increase proceeding) temporary for a period of six months, which may be extended by the PaPUC for an additional six months. The order states that due to the decrease in federal tax rates associated with the 2017 Tax Reform Act, it appears that existing utility rates may be excessive and, therefore, no longer just and reasonable. The order states that the PaPUC is making rates temporary to maximize its authority to establish any negative surcharge, refund or other rate adjustment deemed to be necessary, just and reasonable to account for the tax rate reductions associated with the 2017 Tax Reform Act, and is consistent with the approach that the PaPUC took following federal tax reform in 1986. The order further states that the PaPUC anticipates that after further review and analysis of the responses to data requests, financial information and public comments, it will direct utilities to file appropriate tariffs to account for the tax reductions associated with the 2017 Tax Reform Act that became effective January 1, 2018. Refer to Note 4 - Income Taxes for further discussion of the 2017 Tax Reform Act.

FERC Jurisdiction

Supply Corporation currently has no active rate case on file. Supply Corporation's current rate settlement requires a rate case filing no later than December 31, 2019.

Empire currently has no active rate case on file. Empire’s current rate settlement requires a rate case filing no later than July 1, 2021.

On March 15, 2018, the FERC issued three documents regarding its plans to undertake review of the 2017 Tax Reform Act and its impact on pipelines: a Notice of Proposed Rulemaking which proposes to require pipelines to file a new form isolating the tax impact to each pipeline and also to make an election regarding the action the pipelines will take to address the lower tax rates, one of which is filing a Section 4 rate proceeding; a Policy Statement regarding the treatment of taxes by MLP entities; and a Notice of Inquiry regarding treatment of accumulated deferred income taxes and other tax issues associated with the 2017 Tax Reform Act. The Company cannot predict the outcome of any of these proceedings at this time. Refer to Note 4 - Income Taxes for further discussion of the 2017 Tax Reform Act.