Regulatory Matters	9 Months Ended
Jun. 30, 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. The order stated the NYPSC’s intent to ensure that the net benefits resulting from tax reform were preserved for ratepayers. Pursuant to the order, a technical conference was held with the utilities in February 2018, and the New York Department of Public Service Staff subsequently issued a proposal for accounting and ratemaking treatment of the tax changes. The NYPSC has not yet acted on this proposal. On June 4, 2018, Distribution Corporation filed a petition with the NYPSC regarding Distribution Corporation’s proposed disposition of net federal income tax savings resulting from the 2017 Tax Reform Act seeking authorization to 1) implement a customer refund program to return the net effect of the recent federal income tax rate reduction to Distribution Corporation’s customers and 2) allow Distribution Corporation recovery for the improvements to the Company’s imputed equity ratio directly resulting from the recent federal tax rate reduction. Distribution Corporation has requested the NYPSC to act on its petition in advance of the 2018-2019 winter heating season, but cannot predict the timing or outcome of its petition at this time. 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. 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. On May 17, 2018, the PaPUC issued an Order to Distribution Corporation, superceding and canceling Distribution Corporation’s temporary rates filed pursuant to the March 15, 2018 order and requiring that Distribution Corporation file a tariff supplement establishing temporary rates to implement refunds of 2.2% on customer rates beginning July 1, 2018. Distribution Corporation has filed the necessary tariff supplement to implement such refunds effective July 1, 2018. The May 17, 2018 PaPUC Order provides for a number of options regarding the permanent or temporary status of these rates and associated cost and rate deferral options. The Company is currently evaluating these specific options. 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 filed a Section 4 rate case on June 29, 2018, proposing rate increases to be effective August 1, 2018. The proposed rates reflect an annual cost of service of $71.5 million, a rate base of $246.8 million and a proposed return on equity of 14%. The proposed rate increases are expected to be suspended, with an effective date of January 1, 2019, subject to refund. Lower storage rates are expected to be effective August 1, 2018. If the proposed rate increases finally approved at the end of the proceeding exceed the rates that were in effect at June 29, 2018, but are less than rates put into effect subject to refund on January 1, 2019, Empire would be required to refund the difference between the rates collected subject to refund and the final approved rates, with interest at the FERC-approved rate. If the rates approved at the end of the proceeding are lower than the rates in effect at June 29, 2018, such lower rates will become effective prospectively from the date of the applicable FERC order, and refunds with interest will be limited to the difference between the rates collected subject to refund and the rates in effect at June 29, 2018. On July 18, 2018, the FERC issued a Final Rule in RM18-11-000, et. al, (Order No. 849) which requires 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 or Notice of Inquiry regarding treatment of accumulated deferred income taxes and other tax issues associated with the 2017 Tax Reform Act. Supply Corporation will be required to address the Order by December 6, 2018. At this point, the Company cannot predict the outcome of any action proposed pursuant to the Order. 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. The order stated the NYPSC’s intent to ensure that the net benefits resulting from tax reform were preserved for ratepayers. Pursuant to the order, a technical conference was held with the utilities in February 2018, and the New York Department of Public Service Staff subsequently issued a proposal for accounting and ratemaking treatment of the tax changes. The NYPSC has not yet acted on this proposal. On June 4, 2018, Distribution Corporation filed a petition with the NYPSC regarding Distribution Corporation’s proposed disposition of net federal income tax savings resulting from the 2017 Tax Reform Act seeking authorization to 1) implement a customer refund program to return the net effect of the recent federal income tax rate reduction to Distribution Corporation’s customers and 2) allow Distribution Corporation recovery for the improvements to the Company’s imputed equity ratio directly resulting from the recent federal tax rate reduction. Distribution Corporation has requested the NYPSC to act on its petition in advance of the 2018-2019 winter heating season, but cannot predict the timing or outcome of its petition at this time. 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. 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. On May 17, 2018, the PaPUC issued an Order to Distribution Corporation, superceding and canceling Distribution Corporation’s temporary rates filed pursuant to the March 15, 2018 order and requiring that Distribution Corporation file a tariff supplement establishing temporary rates to implement refunds of 2.2% on customer rates beginning July 1, 2018. Distribution Corporation has filed the necessary tariff supplement to implement such refunds effective July 1, 2018. The May 17, 2018 PaPUC Order provides for a number of options regarding the permanent or temporary status of these rates and associated cost and rate deferral options. The Company is currently evaluating these specific options. 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 filed a Section 4 rate case on June 29, 2018, proposing rate increases to be effective August 1, 2018. The proposed rates reflect an annual cost of service of $71.5 million, a rate base of $246.8 million and a proposed return on equity of 14%. The proposed rate increases are expected to be suspended, with an effective date of January 1, 2019, subject to refund. Lower storage rates are expected to be effective August 1, 2018. If the proposed rate increases finally approved at the end of the proceeding exceed the rates that were in effect at June 29, 2018, but are less than rates put into effect subject to refund on January 1, 2019, Empire would be required to refund the difference between the rates collected subject to refund and the final approved rates, with interest at the FERC-approved rate. If the rates approved at the end of the proceeding are lower than the rates in effect at June 29, 2018, such lower rates will become effective prospectively from the date of the applicable FERC order, and refunds with interest will be limited to the difference between the rates collected subject to refund and the rates in effect at June 29, 2018.

On July 18, 2018, the FERC issued a Final Rule in RM18-11-000, et. al, (Order No. 849) which requires 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 or Notice of Inquiry regarding treatment of accumulated deferred income taxes and other tax issues associated with the 2017 Tax Reform Act. Supply Corporation will be required to address the Order by December 6, 2018. At this point, the Company cannot predict the outcome of any action proposed pursuant to the Order. Refer to Note 4 - Income Taxes for further discussion of the 2017 Tax Reform Act.