Regulatory Matters	3 Months Ended
Dec. 31, 2017
Regulatory Assets and Liabilities, Other Disclosures [Abstract]
Regulatory Matters	Regulatory Matters On April 28, 2016, Distribution Corporation commenced a rate case by filing proposed tariff amendments and supporting testimony requesting approval to increase its annual revenues by approximately $41.7 million. Distribution Corporation explained in the filing that its request for rate relief was necessitated by a revenue requirement driven primarily by rate base growth, higher operating expense and higher depreciation expense, among other things. On January 23, 2017, the administrative law judge assigned to the proceeding issued a recommended decision (RD) in the case. The RD, as revised on January 26, 2017, recommended a rate increase designed to provide additional annual revenues of $8.5 million, an equity ratio, subject to update of 42.3% based on the Company’s equity ratio, and a cost of equity, subject to update of 8.6%. On April 20, 2017, the NYPSC issued an Order adopting some provisions of the RD and modifying or rejecting others. The Order provides for an annual rate increase of $5.9 million. The rate increase became effective May 1, 2017. The Order further provides for a return on equity of 8.7%, and established an equity ratio of 42.9%. The Order also directs the implementation of an earnings sharing mechanism to be in place beginning on April 1, 2018. 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 22, 2017, the federal Tax Cuts and Jobs Act (the 2017 Tax Reform Act) was enacted into law. 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 establishes that the first steps in such process will be soliciting information from its regulated utilities to quantify the impact of the 2017 Tax Reform Act, scheduling a technical conference with the utilities, and the issuance of a NY Department of Public Service Staff (Staff) proposal for accounting and ratemaking treatment of the tax changes. The order further states that once Staff’s proposal is issued, utilities and other interested parties will be invited to comment on Staff’s recommendation. 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.” The Company cannot predict the outcome of this proceeding at this time. Refer to Note 4 - Income Taxes for further discussion of the 2017 Tax Reform Act. FERC Rate Proceedings 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.

Regulatory Matters

On April 28, 2016, Distribution Corporation commenced a rate case by filing proposed tariff amendments and supporting testimony requesting approval to increase its annual revenues by approximately $41.7 million. Distribution Corporation explained in the filing that its request for rate relief was necessitated by a revenue requirement driven primarily by rate base growth, higher operating expense and higher depreciation expense, among other things. On January 23, 2017, the administrative law judge assigned to the proceeding issued a recommended decision (RD) in the case. The RD, as revised on January 26, 2017, recommended a rate increase designed to provide additional annual revenues of $8.5 million, an equity ratio, subject to update of 42.3% based on the Company’s equity ratio, and a cost of equity, subject to update of 8.6%. On April 20, 2017, the NYPSC issued an Order adopting some provisions of the RD and modifying or rejecting others. The Order provides for an annual rate increase of $5.9 million. The rate increase became effective May 1, 2017. The Order further provides for a return on equity of 8.7%, and established an equity ratio of 42.9%. The Order also directs the implementation of an earnings sharing mechanism to be in place beginning on April 1, 2018.

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 22, 2017, the federal Tax Cuts and Jobs Act (the 2017 Tax Reform Act) was enacted into law. 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 establishes that the first steps in such process will be soliciting information from its regulated utilities to quantify the impact of the 2017 Tax Reform Act, scheduling a technical conference with the utilities, and the issuance of a NY Department of Public Service Staff (Staff) proposal for accounting and ratemaking treatment of the tax changes. The order further states that once Staff’s proposal is issued, utilities and other interested parties will be invited to comment on Staff’s recommendation. 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.” The Company cannot predict the outcome of this proceeding at this time. Refer to Note 4 - Income Taxes for further discussion of the 2017 Tax Reform Act.

FERC Rate Proceedings

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.