Winter Storm Uri	9 Months Ended
Winter Storm Uri	Jun. 30, 2021
Unusual or Infrequent Items, or Both [Abstract]
Winter Storm Uri	Winter Storm Uri Overview A historic winter storm impacted supply, market pricing and demand for natural gas in our service territories in mid-February. During this time, the governors of Kansas and Texas each declared a state of emergency, and certain regulatory agencies issued emergency orders that impacted the utility and natural gas industries, including statewide utilities curtailment programs and orders encouraging or requiring jurisdictional natural gas utilities to work to ensure customers were provided with safe and reliable natural gas service. Due to the historic nature of this winter storm, we experienced unforeseeable and unprecedented market pricing for gas costs, which resulted in aggregated natural gas purchases during the month of February of approximately $2.3 billion. These gas costs were paid by the end of March 2021. Incremental Financing As discussed in Note 6 to the unaudited condensed consolidated financial statements, on March 9, 2021, we completed a public offering of $2.2 billion in debt securities and the net proceeds from the offering, after the underwriting discount and offering expenses, were used to substantially fund these purchased gas costs. As a result of this unplanned debt issuance, S&P lowered its long-term/short-term credit ratings from A/A-1 to A-/A-2 and placed our ratings under negative outlook. Moody’s reaffirmed its long-term and short-term credit ratings and placed our ratings under negative outlook. These credit rating adjustments and the issuance of unplanned debt did not impact our ability to satisfy our debt covenants. Regulatory Asset Accounting Our purchased gas costs are recoverable through purchased gas cost adjustment mechanisms in each state where we operate. Due to the unprecedented level of purchased gas costs incurred during Winter Storm Uri, the Kansas Corporation Commission (KCC) and the Railroad Commission of Texas (RRC) issued orders authorizing natural gas utilities to record a regulatory asset to account for the extraordinary costs associated with the winter storm. Pursuant to these orders, as of June 30, 2021, we have recorded a $2.1 billion regulatory asset for incremental costs, including carrying costs, incurred in Kansas ($77.1 million) and Texas ($2,016.7 million) within deferred charges and other assets on our condensed consolidated balance sheet. These costs are subject to review for prudency by each commission and may be adjusted. Income Taxes We deduct our purchased gas costs for federal income tax purposes in the period they are paid. Based on our current projection of taxable income for fiscal 2021 and the expected magnitude of the purchased gas cost deduction, we recorded a $469.4 million (tax effected) increase in our net operating loss carryforwards and a corresponding increase to our deferred tax liability as of June 30, 2021. At June 30, 2021, we had $804.7 million (tax effected) of federal net operating loss carryforwards. The federal net operating loss carryforwards are available to offset future taxable income. Net operating loss carryforwards incurred prior to December 22, 2017 begin to expire in 2029. The Company also has $57.0 million (tax effected) of state net operating loss carryforwards (net of $15.2 million of federal effects) and $1.8 million of state tax credits carryforwards (net of $0.5 million of federal effects). Depending on the jurisdiction in which the state net operating loss was generated, the carryforwards are subject to expiration through the remainder of fiscal 2021. Securitization Legislation To minimize the impact on the customer bill by extending the recovery periods for these unprecedented purchased gas costs, the Kansas and Texas State Legislatures each introduced securitization legislation. The following summarizes the status of the legislation as of the date of this filing. Kansas The Kansas securitization legislation, which became effective April 9, 2021, permits a natural gas public utility, in its sole discretion, to apply to the KCC for a financing order for the recovery of qualified extraordinary costs through the issuance of bonds. Within 25 days after a complete application is filed, the KCC shall establish a procedural schedule that requires it to issue a decision on the application within 180 days from the date a complete application was filed. Utilities may apply for a recovery period of up to 32 years. We plan to file with the KCC an application to securitize the extraordinary gas costs incurred during Winter Storm Uri. Texas On June 16, 2021, House Bill 1520, relating to certain extraordinary costs incurred by certain gas utilities relating to Winter Storm Uri and a study of measures to mitigate similar future costs; providing authority to issue bonds and impose fees and assessments, became effective. House Bill 1520 authorizes the RRC to issue a statewide securitization financing order directing the Texas Public Finance authority to issue bonds (customer rate relief bonds) for gas utilities that choose to participate to recover extraordinary costs incurred to secure gas supply and to provide service during Winter Storm Uri, and to restore gas utility systems after that event, thereby providing rate relief to customers by extending the period during which these extraordinary costs would otherwise be recovered and supporting the financial strength and stability of gas utility companies. The legislation provides that natural gas utilities file an application with the RRC and submit extraordinary gas costs incurred during Winter Storm Uri for a prudency review by July 30, 2021. The RRC has 150 days to approve each application. Following the approval of all applications, the RRC will issue a financing order to the Texas Public Financing Authority authorizing the issuance of customer rate relief bonds to securitize the aggregated extraordinary costs for all participating utilities within 180 days. The participating utilities, as servicers acting on behalf of the state of the securitization financing, will bill and collect customer rate relief charges from their current and future customers and remit the collections to the state issuer of the securitization financing. On July 30, 2021, we filed with the RRC an application to securitize $2.0 billion of extraordinary gas costs incurred during Winter Storm Uri. This amount also includes an estimate of carrying costs and administrative costs that we expect to incur in connection with the resolution of this filing.