Schedule of Regulatory Assets and Liabilities | REGULATORY ASSETS AND LIABILITIES The tables below present a summary of regulatory assets and liabilities, net of amortization, for the periods indicated: March 31, 2023 Current Noncurrent Total ( Thousands of dollars ) Winter weather event costs $ 22,633 $ 28,577 $ 51,210 Pension and postemployment benefit costs 4,159 243,561 247,720 Reacquired debt costs 812 3,166 3,978 MGP remediation costs 98 29,719 29,817 Ad-valorem tax 11,386 — 11,386 WNA 7,994 — 7,994 Customer credit deferrals 15,475 — 15,475 Other 3,641 3,937 7,578 Total regulatory assets, net of amortization 66,198 308,960 375,158 Income tax rate changes — (516,625) (516,625) Over-recovered purchased-gas costs (48,405) — (48,405) Total regulatory liabilities (48,405) (516,625) (565,030) Net regulatory assets and liabilities $ 17,793 $ (207,665) $ (189,872) December 31, 2022 Current Noncurrent Total ( Thousands of dollars ) Winter weather event costs $ 221,926 $ 36,291 $ 258,217 Under-recovered purchased-gas costs 19,755 — 19,755 Pension and postemployment benefit costs — 258,257 258,257 Reacquired debt costs 812 3,347 4,159 MGP remediation costs 98 29,743 29,841 Ad-valorem tax 13,359 — 13,359 WNA 8,474 — 8,474 Customer credit deferrals 9,504 — 9,504 Other 1,644 3,193 4,837 Total regulatory assets, net of amortization 275,572 330,831 606,403 Pension and other postemployment benefit costs (8,228) — (8,228) Income tax rate changes — (529,441) (529,441) Over-recovered purchased-gas costs (39,639) — (39,639) Total regulatory liabilities (47,867) (529,441) (577,308) Net regulatory assets and liabilities $ 227,705 $ (198,610) $ 29,095 Regulatory assets in our consolidated balance sheets, as authorized by various regulatory authorities, are probable of recovery. Base rates and certain riders are designed to provide a recovery of costs during the period such rates are in effect, but do not generally provide for a return on investment for amounts we have deferred as regulatory assets. All of our regulatory assets are subject to review by the respective regulatory authorities during future regulatory proceedings. We are not aware of any evidence that these costs will not be recoverable through either riders, base rates, or securitization. Winter weather event costs - In February 2021, the U.S. experienced Winter Storm Uri, a historic winter weather event impacting supply, market pricing and demand for natural gas in a number of states, including our service territories of Oklahoma, Kansas, and Texas. During this time, the governors of Oklahoma, 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 utility curtailment programs and orders requiring jurisdictional natural gas and electric utilities to do all things possible and necessary to ensure that natural gas and electricity utility services continued to be provided to their customers. Due to the historic nature of this winter weather event, we experienced unforeseeable and unprecedented market pricing for natural gas in our Oklahoma, Kansas, and Texas jurisdictions, which resulted in aggregated natural gas purchases for the month of February 2021 of approximately $2.1 billion. Each state enacted securitization legislation to allow for recovery of the extraordinary gas costs, as well as other authorized expenses related to Winter Storm Uri. Securitization proceeds were received for Oklahoma and Kansas in 2022, and for Texas in 2023. See our Annual Report for more discussion of events surrounding Winter Storm Uri and the securitization of the related regulatory assets. Kansas - In May 2021, Kansas Gas Service filed a motion in its company-specific docket opened by the KCC, requesting a limited waiver of the penalty provisions of its tariff to eliminate the multipliers in the penalty calculation when calculating the penalties to assess on marketers and individually-balanced transportation customers for their unauthorized natural gas usage during Winter Storm Uri. In March 2022, the KCC issued an order approving a settlement which modified the penalty provisions of Kansas Gas Service’s tariffs and included a carrying charge of two percent on amounts due to Kansas Gas Service. Amounts collected from these penalties will reduce the regulatory asset for the winter weather event, up to $52.6 million. Through March 31, 2023, we have collected $51.6 million of these penalties. See Note 14 for additional information about the securitization transaction in Kansas. Texas - Pursuant to securitization legislation enacted in Texas as a result of Winter Storm Uri and a June 2021 RRC Notice to Gas Utilities, Texas Gas Service submitted an application to the RRC in July 2021, for an order authorizing the amount of extraordinary costs for recovery and other such specifications necessary for the issuance of securitized bonds. In February 2022, the RRC issued a single financing order for Texas Gas Service and other natural gas utilities in Texas participating in the securitization process, which included a determination that the approved costs will be collected from customers over a period of not more than 30 years. The TPFA formed the TNG Corporation, a new independent public authority, to issue the securitized bonds. In March 2023, the TNG Corporation completed the issuance of the Customer Rate Relief (Winter Storm Uri), Taxable Series 2023 Bonds and we received our portion of the net proceeds, which was approximately $197 million. The proceeds were used to repay certain indebtedness and for general corporate purposes. Interest costs that exceeded the amount securitized have been deferred and will be addressed in the next general rate proceeding in each jurisdiction in Texas. At March 31, 2023, Texas Gas Service had deferred approximately $36.1 million in extraordinary costs associated with Winter Storm Uri attributable to its former West Texas service area. Pursuant to the approved settlement order, Texas Gas Service began collecting the extraordinary costs, including carrying costs, from those customers in January 2022. The deferred winter weather events costs also include invoiced costs for natural gas purchases during Winter Storm Uri that have not been paid as we work with our suppliers for Kansas and Texas to resolve discrepancies in invoiced amounts. These amounts may be adjusted as the differences with suppliers are resolved. Future adjustments to the amounts are not expected to have a material impact on earnings. Other regulatory assets and liabilities - Purchased-gas costs represent the natural gas costs that have been over- or under-recovered from customers through the purchased-gas cost adjustment mechanisms, and includes natural gas utilized in our operations and premiums paid and any cash settlements received from our purchased natural gas call options. The OCC, KCC and regulatory authorities in Texas have approved the recovery of pension costs and other postemployment benefits costs through rates for Oklahoma Natural Gas, Kansas Gas Service and Texas Gas Service, respectively. The costs recovered through rates are based on the net periodic benefit cost for defined benefit pension and other postemployment costs. Differences, if any, between the net periodic benefit cost, net of deferrals, and the amount recovered through rates are reflected in earnings. We historically have recovered defined benefit pension and other postemployment benefit costs through rates. We believe it is probable that regulators will continue to include the net periodic pension and other postemployment benefit costs in our cost of service. We amortize reacquired debt costs in accordance with the accounting guidelines prescribed by the OCC and the KCC. See Note 12 for additional information regarding our regulatory assets for MGP remediation costs. Ad-valorem tax represents the difference in Kansas Gas Service’s taxes incurred each year above or below the amount approved in base rates. This difference is deferred as a regulatory asset or liability for a 12-month period. Kansas Gas Service then applies an adjustment to customers’ bills to refund the over-collected revenue or bill the under-collected revenue over the subsequent 12 months. Weather normalization represents revenue over- or under-recovered through the WNA rider in Kansas. This amount is deferred as a regulatory asset or liability for a 12-month period. Kansas Gas Service then applies an adjustment to the customers’ bills for 12 months to refund the over-collected revenue or bill the under-collected revenue. The customer credit deferrals and the noncurrent regulatory liability for income tax rate changes represents deferral of the effects of enacted federal and state income tax rate changes on our ADIT and the effects of these changes on our rates. See Note 10 for additional information regarding the impact of income tax rate changes. Recovery through rates resulted in amortization of regulatory assets of approximately $7.0 million and $4.4 million for the three months ended March 31, 2023 and 2022, respectively. |