ONE GAS, INC., 10-Q filed on 5/2/2023
Quarterly Report
v3.23.1
Cover Page - shares
 3 Months Ended
Mar. 31, 2023
Apr. 25, 2023
Document Information [Line Items]    
Document Type 10-Q  
Document Period End Date Mar. 31, 2023  
Entity Registrant Name ONE Gas, Inc.  
Entity Central Index Key 0001587732  
Current Fiscal Year End Date --12-31  
Document Fiscal Year Focus 2023  
Document Fiscal Period Focus Q1  
Amendment Flag false  
Entity Information [Line Items]    
Document Quarterly Report true  
Document Transition Report false  
Entity File Number 001-36108  
Entity Incorporation, State or Country Code OK  
Entity Tax Identification Number 46-3561936  
Entity Address, Address Line One 15 East Fifth Street  
Entity Address, City or Town Tulsa,  
Entity Address, State or Province OK  
Entity Address, Postal Zip Code 74103  
City Area Code (918)  
Local Phone Number 947-7000  
Title of 12(b) Security Common Stock, par value $0.01 per share  
Trading Symbol OGS  
Security Exchange Name NYSE  
Entity Current Reporting Status Yes  
Entity Interactive Data Current Yes  
Entity Filer Category Large Accelerated Filer  
Entity Small Business false  
Entity Emerging Growth Company false  
Entity Shell Company false  
Entity Common Stock, Shares Outstanding   55,389,948
v3.23.1
STATEMENTS OF INCOME - USD ($)
shares in Thousands, $ in Thousands
 3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Regulated Operating Revenue $ 1,032,143 $ 971,459
Cost of natural gas 665,799 639,946
Operating expenses    
Operations and maintenance 126,683 115,095
Depreciation and amortization 71,264 57,137
General taxes 19,166 18,524
Total operating expenses 217,113 190,756
Operating income 149,231 140,757
Other income (expense), net 2,581 (4,145)
Interest expense, net (30,115) (15,595)
Income before income taxes 121,697 121,017
Income taxes (19,076) (22,083)
Net income $ 102,621 $ 98,934
Earnings per share    
Basic $ 1.85 $ 1.83
Diluted $ 1.84 $ 1.83
Weighted Average Number of Shares Outstanding, Basic [Abstract]    
Basic 55,538 53,922
Weighted Average Number of Shares Outstanding, Diluted [Abstract]    
Diluted 55,800 54,030
Common Stock, Dividends, Per Share, Declared $ 0.65 $ 0.62
v3.23.1
STATEMENTS OF COMPREHENSIVE INCOME STATEMENTS OF COMPREHENSIVE INCOME - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Net income $ 102,621 $ 98,934
Other comprehensive income (loss), net of tax    
Change in pension and other postemployment benefit plan liability, net of tax of $— and $(19), respectively 0 69
Other comprehensive income, net of tax 0 69
Comprehensive income $ 102,621 $ 99,003
v3.23.1
STATEMENTS OF COMPREHENSIVE INCOME STATEMENTS OF COMPREHENSIVE INCOME Parenthetical - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Pension and other postemployment benefit plans, tax $ 0 $ (19)
v3.23.1
BALANCE SHEETS - USD ($)
$ in Thousands
Mar. 31, 2023
Dec. 31, 2022
Property, plant and equipment    
Property, plant and equipment $ 7,957,407 $ 7,834,557
Accumulated depreciation and amortization 2,226,565 2,205,717
Net property, plant and equipment 5,730,842 5,628,840
Cash and Cash Equivalents 7,809 9,681
Restricted Cash and Cash Equivalents 19,117 8,446
Cash, cash equivalents, restricted cash and restricted cash equivalents 26,926 18,127
Current assets    
Accounts receivable, net 493,573 553,834
Materials and supplies 73,033 70,873
Natural Gas in Storage 98,966 269,205
Regulatory assets, Current 66,198 275,572
Other current assets 29,773 29,997
Total current assets 788,469 1,217,608
Goodwill and other assets    
Regulatory assets, Noncurrent 308,960 330,831
Other Intangible Assets, Net 316,749 323,838
Goodwill 157,953 157,953
Other assets 117,279 117,326
Total goodwill and other assets 900,941 929,948
Total assets 7,420,252 7,776,396
Equity and long-term debt    
Common stock, $0.01 par value: authorized 250,000,000 shares; issued and outstanding 55,389,050 shares at March 31, 2023; issued and outstanding 55,349,954 shares at December 31, 2022 553 553
Paid-in Capital 1,933,468 1,932,714
Retained earnings 718,163 651,863
Accumulated other comprehensive loss (704) (704)
Total equity 2,651,480 2,584,426
Other Long-Term Debt, Noncurrent 1,580,018 2,352,400
Securitized utility tariff bonds, excluding current maturities, net of issuance costs 295,555 309,343
Long-Term Debt, Excluding Current Maturities, Total 1,875,573 2,661,743
Total equity and long-term debt 4,527,053 5,246,169
Current liabilities    
Long-term Debt, Current Maturities 772,742 12
Current maturities of securitized utility tariff bonds 34,497 20,716
Short-term debt 280,000 552,000
Accounts payable 197,619 360,493
Accrued taxes other than income 76,148 78,352
Regulatory Liability, Current 48,405 47,867
Customer deposits 56,467 57,854
Other current liabilities 76,397 72,125
Total current liabilities 1,542,275 1,189,419
Deferred credits and other liabilities    
Deferred income taxes 720,640 698,456
Regulatory Liability, Noncurrent 516,625 529,441
Employee benefit obligations 19,599 19,587
Other deferred credits 94,060 93,324
Liabilities, Other than Long-term Debt, Noncurrent 1,350,924 1,340,808
Commitments and contingencies
Total liabilities and equity $ 7,420,252 $ 7,776,396
v3.23.1
BALANCE SHEETS BALANCE SHEETS Parenthetical - $ / shares
Mar. 31, 2023
Dec. 31, 2022
Common stock, par value per share $ 0.01  
Common stock, shares authorized 250,000,000  
Common stock, shares issued 55,389,050 55,349,954
Common stock, shares outstanding 55,389,050 55,349,954
v3.23.1
STATEMENTS OF CASH FLOWS - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Operating activities    
Net income $ 102,621 $ 98,934
Adjustments to reconcile net income to net cash provided by operating activities:    
Depreciation and amortization 71,264 57,137
Deferred income taxes 9,364 (6,849)
Share-based compensation expense 2,821 2,695
Provision for doubtful accounts 3,925 1,338
Proceeds from Securitization Bonds, Operating Activities 197,366 0
Changes in assets and liabilities:    
Accounts receivable 56,336 (154,278)
Materials and supplies (2,160) 705
Natural gas in storage 170,239 100,701
Payments for Removal Costs (13,567) (9,554)
Accounts payable (157,533) (56,863)
Accrued taxes other than income (2,204) 8,118
Customer deposits (1,387) (1,349)
Increase (Decrease) In Regulatory Assets And Liabilities Current, net 5,585 36,374
Increase (Decrease) In Regulatory Assets And Liabilities Noncurrent, net 21,871 66,002
Increase (Decrease) in Other Current Assets and Liabilities, Net 3,573 (12,438)
Increase (Decrease) in Other Noncurrent Assets and Liabilities, Net 952 (23,037)
Cash provided by operating activities 469,066 107,636
Investing activities    
Capital expenditures (151,030) (113,307)
Payments for Other Investing Activities (292) (608)
Proceeds from Sale of Other Assets, Investing Activities 1,443 549
Cash used in investing activities (149,879) (113,366)
Financing activities    
Borrowings (repayments) of short-term debt, net (272,000) 11,165
Proceeds from Issuance of Common Stock 0 34,468
Dividends paid (36,002) (33,285)
Payment, Tax Withholding, Share-based Payment Arrangement (2,386) (3,023)
Cash used in financing activities (310,388) 9,325
Change in cash and cash equivalents 8,799 3,595
Cash, cash equivalents, restricted cash and restricted cash equivalents at beginning of period 18,127 8,852
Cash, cash equivalents, restricted cash and restricted cash equivalents at end of period 26,926 12,447
Interest Paid, Excluding Capitalized Interest, Operating Activities 33,729 28,017
Income Taxes Paid, Net $ (1,870) $ 0
v3.23.1
STATEMENT OF CHANGES IN EQUITY - USD ($)
$ in Thousands
Total
Common Stock [Member]
Paid-in Capital [Member]
Retained Earnings [Member]
Accumulated Other Comprehensive Income (Loss) [Member]
Shares issued, beginning balance at Dec. 31, 2021   53,633,210      
Common stock issued, shares   456,607      
Shares issued, ending balance at Mar. 31, 2022   54,089,817      
Equity, beginning balance at Dec. 31, 2021 $ 2,349,532 $ 536 $ 1,790,362 $ 565,161 $ (6,527)
Net income 98,934 0 0 98,934 0
Other comprehensive income 69 0 0 0 69
Common stock issued, value 34,140 5 34,135 0 0
Common stock dividends - $0.65 and $0.62 per share per quarter as of 2022 and 2021, respectively (33,285) 0 274 (33,559) 0
Equity, ending balance at Mar. 31, 2022 $ 2,449,390 $ 541 1,824,771 630,536 (6,458)
Shares issued, beginning balance at Dec. 31, 2022 55,349,954 55,349,954      
Common stock issued, shares   39,096      
Shares issued, ending balance at Mar. 31, 2023 55,389,050 55,389,050      
Equity, beginning balance at Dec. 31, 2022 $ 2,584,426 $ 553 1,932,714 651,863 (704)
Net income 102,621 0 0 102,621 0
Other comprehensive income 0        
Common stock issued, value 435 0 435 0 0
Common stock dividends - $0.65 and $0.62 per share per quarter as of 2022 and 2021, respectively (36,002) 0 319 (36,321) 0
Equity, ending balance at Mar. 31, 2023 $ 2,651,480 $ 553 $ 1,933,468 $ 718,163 $ (704)
v3.23.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Notes)
 3 Months Ended
Mar. 31, 2023
Significant Accounting Policies [Line Items]  
SIGNIFICANT ACCOUNTING POLICIES SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
Our accompanying unaudited consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC. These statements also have been prepared in accordance with GAAP and reflect all adjustments that, in our opinion, are necessary for a fair statement of the results for the interim periods presented. All such adjustments are of a normal recurring nature. The 2022 year-end consolidated balance sheet data was derived from audited consolidated financial statements but does not include all disclosures required by GAAP. These unaudited consolidated financial statements should be read in conjunction with the audited consolidated financial statements and footnotes in our Annual Report. Our significant accounting policies are described in Note 1 of our Notes to Consolidated Financial Statements in our Annual Report. The preparation of these financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the amounts and disclosures in the financial statements. Although management believes these estimates are reasonable, actual results could differ materially from these estimates. Due to the seasonal nature of our business, the results of operations for the three months ended March 31, 2023, are not necessarily indicative of the results that may be expected for a 12-month period.

We provide natural gas distribution services to approximately 2.3 million customers in Oklahoma, Kansas and Texas through our three divisions, Oklahoma Natural Gas, Kansas Gas Service and Texas Gas Service, respectively. We primarily serve residential, commercial and transportation customers in all three states.

Segments - We operate in one reportable business segment: regulated public utilities that deliver natural gas primarily to residential, commercial and transportation customers. Our accounting policies are the same as those described in Note 1 of the Notes to Consolidated Financial Statements in our Annual Report. We evaluate our financial performance principally on net income. For the three months ended March 31, 2023 and 2022, we had no single external customer from which we received 10 percent or more of our gross revenues.

Property, Plant and Equipment and Asset Removal Costs - Accounts payable for construction work in progress and asset removal costs decreased by approximately $5.3 million and $8.1 million for the three months ended March 31, 2023 and 2022, respectively. Such amounts are not included in capital expenditures or asset removal costs in our consolidated statements of cash flows.

Accounts Receivable - Accounts receivable represent valid claims against nonaffiliated customers for natural gas sold or services rendered, net of allowances for doubtful accounts. We assess the creditworthiness of our customers. Those customers who do not meet minimum standards may be required to provide security, including deposits and other forms of collateral, when appropriate and allowed by our tariffs. With approximately 2.3 million customers across three states, we are not exposed materially to a concentration of credit risk. We maintain an allowance for doubtful accounts based upon factors surrounding the credit risk of customers, historical trends, consideration of the current environment and other information. We recover natural gas costs related to accounts written off when they are deemed uncollectible through the purchased-gas cost adjustment mechanisms in each of our jurisdictions. At March 31, 2023 and December 31, 2022, our allowance for doubtful accounts was $19.7 million and $16.7 million, respectively.

Reclassifications -A reclassification has been made in the prior-year financial statements to conform to the current-year presentation. We have updated our consolidated balance sheet at December 31, 2022, to disaggregate “current maturities of other long-term debt,” which had previously been included in “other current liabilities,” to conform to our current-year presentation.
v3.23.1
REVENUE (Notes)
 3 Months Ended
Mar. 31, 2023
Revenue from Contract with Customer REVENUE
The following table sets forth our revenues disaggregated by source for the periods indicated:
Three Months Ended
March 31,
20232022
(Thousands of dollars)
Natural gas sales to customers$966,359 $925,157 
Transportation revenues38,527 36,316 
Securitization customer charges (Note 14)11,933 — 
Miscellaneous revenues5,898 4,496 
Total revenues from contracts with customers1,022,717 965,969 
Other revenues - natural gas sales related5,790 2,346 
Other revenues 3,636 3,144 
Total other revenues9,426 5,490 
Total revenues$1,032,143 $971,459 
Accrued unbilled natural gas sales revenues at March 31, 2023 and December 31, 2022, were $146.8 million and $269.5 million, respectively, and are included in accounts receivable on our consolidated balance sheets.
v3.23.1
REGULATORY ASSETS AND LIABILITIES (Notes)
 3 Months Ended
Mar. 31, 2023
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]  
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
CurrentNoncurrentTotal
(Thousands of dollars)
Winter weather event costs$22,633 $28,577 $51,210 
Pension and postemployment benefit costs4,159 243,561 247,720 
Reacquired debt costs812 3,166 3,978 
MGP remediation costs98 29,719 29,817 
Ad-valorem tax11,386 — 11,386 
WNA7,994 — 7,994 
Customer credit deferrals15,475 — 15,475 
Other3,641 3,937 7,578 
Total regulatory assets, net of amortization66,198 308,960 375,158 
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
CurrentNoncurrentTotal
(Thousands of dollars)
Winter weather event costs$221,926 $36,291 $258,217 
Under-recovered purchased-gas costs19,755 — 19,755 
Pension and postemployment benefit costs— 258,257 258,257 
Reacquired debt costs812 3,347 4,159 
MGP remediation costs98 29,743 29,841 
Ad-valorem tax13,359 — 13,359 
WNA8,474 — 8,474 
Customer credit deferrals9,504 — 9,504 
Other1,644 3,193 4,837 
Total regulatory assets, net of amortization275,572 330,831 606,403 
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.
v3.23.1
CREDIT FACILITIES (Notes)
 3 Months Ended
Mar. 31, 2023
Short-term Debt [Line Items]  
Short-term Debt [Text Block] CREDIT FACILITY AND SHORT-TERM DEBT
In March 2023, we entered into an extension agreement related to the ONE Gas Credit Agreement that extends the maturity date to March 16, 2028, from March 16, 2027. All other terms and conditions of the ONE Gas Credit Agreement remain in full force and effect.

The ONE Gas Credit Agreement provides for a $1.0 billion revolving unsecured credit facility and includes a $20 million letter of credit subfacility and a $60 million swingline subfacility. We can request an increase in commitments of up to an additional
$500 million upon satisfaction of customary conditions, including receipt of commitments from either new lenders or increased commitments from existing lenders. The ONE Gas Credit Agreement is available to provide liquidity for working capital, capital expenditures, acquisitions and mergers, the issuance of letters of credit and for other general corporate purposes.

The ONE Gas Credit Agreement contains certain financial, operational and legal covenants. Among other things, these covenants include maintaining ONE Gas’ total debt-to-capital ratio of no more than 70 percent at the end of any calendar quarter. At March 31, 2023, our total debt-to-capital ratio was 53 percent and we were in compliance with all covenants under the ONE Gas Credit Agreement. We may reduce the unutilized portion of the ONE Gas Credit Agreement in whole or in part without premium or penalty. The ONE Gas Credit Agreement contains customary events of default. Upon the occurrence of certain events of default, the obligations under the ONE Gas Credit Agreement may be accelerated and the commitments may be terminated.

At March 31, 2023, we had $1.2 million in letters of credit issued and no borrowings under the ONE Gas Credit Agreement, with $998.8 million of remaining credit, which is available to repay any of our commercial paper borrowings.

We have a commercial paper program under which we may issue unsecured commercial paper up to a maximum amount of $1.0 billion to fund short-term borrowing needs. The maturities of the commercial paper vary but may not exceed 270 days from the date of issue. Commercial paper is generally sold at par less a discount representing an interest factor. At March 31, 2023 and December 31, 2022, we had $280.0 million and $552.0 million of commercial paper outstanding with a weighted-average interest rate of 5.41 percent and 4.75 percent, respectively.
v3.23.1
LONG-TERM DEBT (Notes)
 3 Months Ended
Mar. 31, 2023
Long-Term Debt, Unclassified [Abstract]  
Long-term Debt [Text Block] LONG-TERM DEBT
The table below presents a summary of our long-term debt outstanding for the periods indicated:

Interest rate at March 31, 2023
March 31, 2023December 31, 2022
(Thousands of dollars)
Senior unsecured notes:
Senior unsecured notes due February 20243.610%$300,000 $300,000 
Senior unsecured notes due March 20241.100%473,000 473,000 
Senior unsecured notes due May 20302.000%300,000 300,000 
Senior unsecured notes due September 20324.250%300,000 300,000 
Senior unsecured notes due February 20444.658%600,000 600,000 
Senior unsecured notes due November 20484.500%400,000 400,000 
Total senior unsecured notes2,373,000 2,373,000 
KGSS-I Securitized Utility Tariff Bonds5.486%336,000 336,000 
Other8.000%1,247 1,250 
Unamortized discounts on long-term debt(7,531)(7,636)
Debt issuance costs(19,904)(20,143)
Total long-term debt, net2,682,812 2,682,471 
Less: current maturities of securitized utility tariff bonds34,497 20,716 
Less: current maturities of long-term debt772,742 12 
Noncurrent portion of long-term debt, net$1,875,573 $2,661,743 

Senior Notes - The indenture governing our Senior Notes includes an event of default upon the acceleration of other indebtedness of $100 million or more. Such events of default would entitle the trustee or the holders of 25 percent in aggregate principal amount of the outstanding Senior Notes to declare those Senior Notes immediately due and payable in full.

Depending on the series, we may redeem our Senior Notes at par, plus accrued and unpaid interest to the redemption date, starting three months or six months before their maturity dates. Prior to these dates, we may redeem these Senior Notes, in whole or in part, at a redemption price equal to the principal amount, plus accrued and unpaid interest and a make-whole premium. The redemption price will never be less than 100 percent of the principal amount of the respective Senior Note plus accrued and unpaid interest to the redemption date. Our Senior Notes are senior unsecured obligations, ranking equally in right of payment with all of our existing and future unsecured senior indebtedness.
Securitized Utility Tariff Bonds - The KGSS-I Securitized Utility Tariff Bonds are governed by an indenture between KGSS-I and the indenture trustee. The indenture contains certain covenants that restrict KGSS-I’s ability to sell, transfer, convey, exchange, or otherwise dispose of its assets. See Note 14 for additional discussion of the Kansas securitization transaction.
v3.23.1
EQUITY (Notes)
 3 Months Ended
Mar. 31, 2023
Class of Stock [Line Items]  
Stockholders' Equity Note Disclosure [Text Block] EQUITY
Equity Forward Agreement - In March 2023, we entered into an underwriting agreement and a forward sale agreement for 2.0 million shares of our common stock. The forward sale agreement provides for settlement on a date, or dates, to be specified at our discretion, but which will occur no later than December 29, 2023, for 1.4 million shares of common stock and by December 31, 2024, for the remaining balance. Had we settled this forward agreement as of March 31, 2023, we would have generated net proceeds of approximately $152.7 million.

At-the-Market Equity Program - In February 2023, we entered into an at-the-market equity distribution agreement under which we may issue and sell shares of our common stock with an aggregate offering price up to $300 million (including any shares of common stock that may be sold pursuant to the master forward sale confirmation entered into in connection with the equity distribution agreement and the related supplemental confirmations). This at-the-market equity program replaced our previous at-the-market equity program, which began in February 2020, and expired in February 2023. The program allows us to offer and sell our common stock at prices we deem appropriate. Sales of common stock are made by means of ordinary brokers’ transactions on the NYSE, in block transactions or as otherwise agreed to between us and the sales agent. We are under no obligation to offer and sell common stock under the program. At March 31, 2023, we had $300 million of equity available for issuance under the program.

For the three months ended March 31, 2022, we issued and sold 403,792 shares of our common stock for $35.0 million, generating proceeds, net of issuance costs, of $34.7 million.

Had we settled all shares under our outstanding forward sale agreements as of March 31, 2023, we would have generated net proceeds of approximately $174.4 million, as detailed below:

MaturityShares SoldNet Proceeds Available
(in thousands)		Forward Price
At-the-Market Equity Program
December 29, 2023289,403 $21,748 $75.15 
Equity Forward Agreement
December 29, 20231,400,000 106,863 76.33 
December 31, 2024600,000 45,798 76.33 
Total March 2023 Equity Forward Agreement2,000,000 152,661 76.33 
Total forward sale agreements2,289,403 $174,409 $76.18 

Dividends Declared - In May 2023, we declared a dividend of $0.65 per share ($2.60 per share on an annualized basis) for shareholders of record as of May 17, 2023, payable on June 2, 2023.
v3.23.1
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Notes)
 3 Months Ended
Mar. 31, 2023
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]  
Comprehensive Income (Loss) Note ACCUMULATED OTHER COMPREHENSIVE LOSS
The following table sets forth the effect of reclassifications from accumulated other comprehensive loss in our consolidated statements of income for the periods indicated:
Three Months EndedAffected Line Item in the
Details About Accumulated OtherMarch 31,Consolidated Statements
Comprehensive Loss Components20232022of Income
(Thousands of dollars)
Pension and other postemployment benefit plan obligations (a)
Amortization of net loss$490 $8,201 
Amortization of unrecognized prior service cost (credit)131 10 
621 8,211 
Regulatory adjustments (b)(621)(8,123)
— 88 Income before income taxes
— (19)Income tax expense
Total reclassifications for the period$— $69 Net income
(a) These components of accumulated other comprehensive loss are included in the computation of net periodic benefit cost. See Note 9 for additional detail of our net periodic benefit cost.
(b) Regulatory adjustments represent pension and other postemployment benefit costs expected to be recovered through rates and are deferred as part of our regulatory assets. See Note 3 for additional disclosures of regulatory assets and liabilities.
v3.23.1
EARNINGS PER SHARE (Notes)
 3 Months Ended
Mar. 31, 2023
EARNINGS PER SHARE [Line Items]  
Earnings Per Share [Text Block] EARNINGS PER SHARE
Basic EPS is calculated by dividing net income by the daily weighted-average number of common shares outstanding during the periods presented, which includes fully vested stock awards that have not yet been issued as common stock. Diluted EPS is based on shares outstanding for the calculation of basic EPS, plus unvested stock awards granted under our compensation plans and equity forward sale agreements, but only to the extent these instruments dilute earnings per share.

The following tables set forth the computation of basic and diluted EPS from continuing operations for the periods indicated:
Three Months Ended March 31, 2023
IncomeSharesPer Share
Amount
(Thousands, except per share amounts)
Basic EPS Calculation
Net income available for common stock
$102,621 55,538 $1.85 
Diluted EPS Calculation
Effect of dilutive securities— 262 
Net income available for common stock and common stock equivalents$102,621 55,800 $1.84 
Three Months Ended March 31, 2022
IncomeSharesPer Share
Amount
(Thousands, except per share amounts)
Basic EPS Calculation
Net income available for common stock
$98,934 53,922 $1.83 
Diluted EPS Calculation
Effect of dilutive securities— 108 
Net income available for common stock and common stock equivalents$98,934 54,030 $1.83 
v3.23.1
EMPLOYEE BENEFIT PLANS (Notes)
 3 Months Ended
Mar. 31, 2023
Defined Benefit Plans and Other Postretirement Benefit Plans Disclosures [Abstract]  
Employee Benefit Plans (Notes) EMPLOYEE BENEFIT PLANS
The following tables set forth the components of net periodic benefit cost for our pension and other postemployment benefit plans for the periods indicated:
Pension Benefits
Three Months Ended
March 31,
20232022
(Thousands of dollars)
Components of net periodic benefit cost (credit)
Service cost$1,811 $3,094 
Interest cost 10,607 7,804 
Expected return on assets (14,879)(14,613)
Amortization of unrecognized prior service cost93 — 
Amortization of net loss 502 8,147 
Net periodic benefit cost (credit)$(1,866)$4,432 

Other Postemployment Benefits
Three Months Ended
March 31,
20232022
(Thousands of dollars)
Components of net periodic benefit cost (credit)
Service cost$183 $318 
Interest cost 2,288 1,612 
Expected return on assets (2,432)(3,295)
Amortization of unrecognized prior service cost38 10 
Amortization of net (gain) loss (12)54 
Net periodic benefit cost (credit)$65 $(1,301)

We recover qualified pension benefit plan and other postemployment benefit plan costs through rates charged to our customers. Certain regulatory authorities require that the recovery of these costs be based on specific guidelines. The difference between these regulatory-based amounts and the periodic benefit cost calculated pursuant to GAAP is deferred as a regulatory asset or liability and amortized to expense over periods in which this difference will be recovered in rates, as authorized by the applicable regulatory authorities. For the three months ended March 31, 2023 and 2022, regulatory deferrals related to net periodic benefit cost were not material.

We capitalize all eligible service cost and non-service cost components under the accounting requirements of ASC Topic 980 (Regulated Operations) for rate-regulated entities. Our consolidated balance sheets reflect the capitalized non-service cost components as a regulatory asset in the amount of $1.4 million and $2.8 million at March 31, 2023 and December 31, 2022, respectively. See Note 3 of the Notes to Consolidated Financial Statements in this Quarterly Report for additional information.
v3.23.1
INCOME TAXES (Notes)
 3 Months Ended
Mar. 31, 2023
Income Tax Disclosure [Abstract]  
Income Tax Disclosure INCOME TAXES
We use an estimated annual effective tax rate for purposes of determining the income tax provision during interim reporting periods. In calculating our estimated annual effective tax rate, we consider forecasted annual pre-tax income and estimated permanent book versus tax differences, as well as tax credits. Adjustments to the effective tax rate and estimates will occur as information and assumptions change.

At March 31, 2023, we have no uncertain tax positions. Changes in tax laws or tax rates are recognized in the financial reporting period that includes the enactment date. We are no longer subject to income tax examination for years prior to 2019.

Income tax expense reflects credits for the amortization of the regulatory liability associated with EDIT that was returned to customers of $9.9 million and $7.9 million for the three months ended March 31, 2023 and 2022, respectively.
v3.23.1
OTHER INCOME AND OTHER EXPENSE (Notes)
 3 Months Ended
Mar. 31, 2023
Other Income and Other Expense Disclosure [Text Block] OTHER INCOME AND OTHER EXPENSE
The following table sets forth the components of other income and other expense for the periods indicated:
Three Months Ended
March 31,
20232022
(Thousands of dollars)
Net periodic benefit (cost) credit other than service cost$908 $(588)
Earnings (losses) on investments associated with nonqualified employee benefit plans1,613 (2,833)
Other, net60 (724)
Total other income (expense), net$2,581 $(4,145)
v3.23.1
COMMITMENTS AND CONTINGENCIES (Notes)
 3 Months Ended
Mar. 31, 2023
Commitments and Contingencies [Line Items]  
COMMITMENTS AND CONTINGENCIES COMMITMENTS AND CONTINGENCIES
Environmental Matters - We are subject to multiple laws and regulations regarding protection of the environment and natural and cultural resources, which affect many aspects of our present and future operations. Regulated activities include, but are not limited to, those involving air emissions, storm water and wastewater discharges, handling and disposal of solid and hazardous wastes, wetland preservation, plant and wildlife protection, hazardous materials use, storage and transportation, and pipeline and facility construction. These laws and regulations require us to obtain and/or comply with a wide variety of environmental clearances, registrations, licenses, permits and other approvals. Failure to comply with these laws, regulations, licenses and permits or the discovery of presently unknown environmental conditions may expose us to fines, penalties and/or interruptions in our operations that could be material to our results of operations. In addition, emission controls and/or other regulatory or permitting mandates under the CAA and other similar federal and state laws could require unexpected capital expenditures. We cannot assure that existing environmental statutes and regulations will not be revised or that new regulations will not be adopted or become applicable to us. Revised or additional statutes or regulations that result in increased compliance costs or additional operating restrictions could have a material adverse effect on our business, financial condition and results of operations. Our expenditures for environmental investigation and remediation compliance to-date have not been significant in relation to our financial position, results of operations or cash flows, and our expenditures related to environmental matters had no material effects on earnings or cash flows during the three months ended March 31, 2023 and 2022.

We own or retain legal responsibility for certain environmental conditions at 12 former MGP sites in Kansas. These sites contain contaminants generally associated with MGP sites and are subject to control or remediation under various environmental laws and regulations. A consent agreement with the KDHE governs all environmental investigation and remediation work at these sites. The terms of the consent agreement require us to investigate these sites and set remediation activities based upon the results of the investigations and risk analysis. Remediation typically involves the management of contaminated soils and may involve removal of structures and monitoring and/or remediation of groundwater. Regulatory closure has been achieved at five of the 12 sites, but these sites remain subject to potential future requirements that may result in additional costs.

We have an AAO that allows Kansas Gas Service to defer and seek recovery of costs necessary for investigation and remediation at, and nearby, these 12 former MGP sites that are incurred after January 1, 2017, up to a cap of $15.0 million, net of any related insurance recoveries. Costs approved for recovery in a future rate proceeding would then be amortized over a 15-year period. The unamortized amounts will not be included in rate base or accumulate carrying charges. Following a determination that future investigation and remediation work approved by the KDHE is expected to exceed $15.0 million, net of any related insurance recoveries, Kansas Gas Service will be required to file an application with the KCC for approval to increase the $15.0 million cap. At March 31, 2023 and December 31, 2022, we have deferred $29.8 million for accrued investigation and remediation costs pursuant to our AAO. Kansas Gas Service expects to file an application as soon as practicable after the KDHE approves the plans we have submitted.

We have completed or are addressing removal of the source of soil contamination at all 12 sites and continue to monitor groundwater at seven of the 12 sites according to plans approved by the KDHE. In 2019, we completed a project to remove a source of contamination and associated contaminated materials at the twelfth site where no active soil remediation had previously occurred. In 2022, we completed a remediation project to remove a source of contamination and contaminated materials at one of the MGP sites. Remediation plans concerning various sites were submitted to the KDHE in 2021 and 2020 and the KDHE has provided comments that we are addressing. We are also working on a remediation plan for an additional site for submission to the KDHE.
We also own or retain legal responsibility for certain environmental conditions at a former MGP site in Texas. At the request of the TCEQ, we began investigating the level and extent of contamination associated with the site under their Texas Risk Reduction Program. A preliminary site investigation revealed that this site contains contaminants generally associated with MGP sites and is subject to control or remediation under various environmental laws and regulations. Impacts have been identified in the soil and groundwater at the site with limited impacts observed in surrounding areas. In April 2022, we submitted a remediation work plan to address the areas impacted to the TCEQ. At March 31, 2023, estimated costs associated with expected remediation activities for this site are not material.

Our expenditures for environmental evaluation, mitigation, remediation and compliance to date have not been significant in relation to our financial position, results of operations or cash flows, and our expenditures related to environmental matters had no material effects on earnings or cash flows during the three months ended March 31, 2023 and 2022. The reserve for remediation of our MGP sites was $12.7 million at March 31, 2023 and December 31, 2022.

Pipeline Safety - We are subject to regulation under federal pipeline safety statutes and any analogous state regulations. These include safety requirements for the design, construction, operation, and maintenance of pipelines, including transmission and distribution pipelines. At the federal level, we are regulated by PHMSA. PHMSA regulations require the following for certain pipelines: inspection and maintenance plans; integrity management programs, including the determination of pipeline integrity risks and periodic assessments on certain pipeline segments; an operator qualification program, which includes certain trainings; a public awareness program that provides certain information; and a control room management plan.

As part of the Consolidated Appropriations Act, 2021, the PIPES Act reauthorized PHMSA through 2023 and directed the agency to move forward with several regulatory actions, including the “Pipeline Safety: Class Location Change Requirements” and the “Pipeline Safety: Safety of Gas Transmission and Gathering Pipelines” proposed rulemakings. Congress has also instructed PHMSA to issue final regulations that will require operators of non-rural gas gathering lines and new and existing transmission and distribution pipeline facilities to conduct certain leak detection and repair programs and to require facility inspection and maintenance plans to align with those regulations. To the extent such rulemakings impose more stringent requirements on our facilities, we may be required to incur expenditures that may be material.

Legal Proceedings - We are a party to various litigation matters and claims that have arisen in the normal course of our operations. While the results of litigation and claims cannot be predicted with certainty, we believe the reasonably possible losses from such matters, individually and in the aggregate, are not material. Additionally, we believe the probable outcome of such matters will not have a material adverse effect on our results of operations, financial position or cash flows.
v3.23.1
DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Notes)
 3 Months Ended
Mar. 31, 2023
Fair Value Disclosures [Abstract]  
Fair Value Disclosures DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS
Accounting Treatment - We record all derivative instruments at fair value, with the exception of normal purchases and normal sales that are expected to result in physical delivery. The accounting for changes in the fair value of a derivative instrument depends on whether it has been designated and qualifies as part of a hedging relationship and, if so, the reason for holding it, or if regulatory requirements impose a different accounting treatment.

If certain conditions are met, we may elect to designate a derivative instrument as a hedge of exposure to changes in fair values or cash flows. We have not elected to designate any of our derivative instruments as hedges.

The table below summarizes the various ways in which we account for our derivative instruments and the impact on our consolidated financial statements:
  Recognition and Measurement
Accounting Treatment Balance Sheet Income Statement
Normal purchases and
normal sales		-Fair value not recorded-Change in fair value not recognized in earnings
Mark-to-market-Recorded at fair value-Change in fair value recognized in, and recoverable through, the purchased-gas cost adjustment mechanisms

Fair Value Measurements - We define fair value as the price that would be received from the sale of an asset or the transfer of a liability in an orderly transaction between market participants at the measurement date. We use the market and income approaches to determine the fair value of our assets and liabilities and consider the markets in which the transactions are
executed. We measure the fair value of a group of financial assets and liabilities consistent with how a market participant would price the net risk exposure at the measurement date.

Fair Value Hierarchy - At each balance sheet date, we utilize a fair value hierarchy to classify fair value amounts recognized or disclosed in our consolidated financial statements based on the observability of inputs used to estimate such fair value. The levels of the hierarchy are described below:

•Level 1 - Unadjusted quoted prices in active markets for identical assets or liabilities;
•Level 2 - Significant observable pricing inputs other than quoted prices included within Level 1 that are, either directly or indirectly, observable as of the reporting date. Essentially, this represents inputs that are derived principally from or corroborated by observable market data; and
•Level 3 - May include one or more unobservable inputs that are significant in establishing a fair value estimate. These unobservable inputs are developed based on the best information available and may include our own internal data.

We recognize transfers into and out of the levels as of the end of each reporting period.

Determining the appropriate classification of our fair value measurements within the fair value hierarchy requires management’s judgment regarding the degree to which market data is observable or corroborated by observable market data. We categorize derivatives for which fair value is determined using multiple inputs within a single level, based on the lowest level input that is significant to the fair value measurement in its entirety.

Derivative Instruments - At March 31, 2023, we had no purchased natural gas call options. At December 31, 2022, we held purchased natural gas call options for the heating season ended March 2023, with total notional amounts of 19.4 Bcf, for which we paid premiums of $14.1 million, and which had no fair value. These contracts are included in, and recoverable through, our purchased-gas cost adjustment mechanisms. Additionally, premiums paid, changes in fair value and any settlements received associated with these contracts are deferred as part of our unrecovered purchased-gas costs in our consolidated balance sheets. Our natural gas call options are classified as Level 1, as fair value amounts are based on unadjusted quoted prices in active markets including settled prices on the New York Mercantile Exchange. There were no transfers between levels for the periods presented.

Other Financial Instruments - The approximate fair value of cash and cash equivalents, restricted cash and cash equivalents, accounts receivable and accounts payable is equal to book value, due to the short-term nature of these items. Our cash and cash equivalents and restricted cash and cash equivalents are comprised of cash and money market accounts, which are classified as Level 1.

We record certain financial assets and liabilities at fair value at each balance sheet date. The table below summarizes the balances of these assets at March 31, 2023 and December 31, 2022:
March 31, 2023
Level 1Level 2Total
Other Current Assets:
United States treasury notes$726 $— $726 
Corporate bonds— 2,359 2,359 
Other Assets:
United States treasury notes3,326 — 3,326 
Corporate bonds— 6,913 6,913 

December 31, 2022
Level 1Level 2Total
Other Current Assets:
United States treasury notes$1,204 $— $1,204 
Corporate bonds— 2,086 2,086 
Other Assets:
United States treasury notes3,491 — 3,491 
Corporate bonds— 7,624 7,624 

Commercial paper is due upon demand and, therefore, the carrying amounts approximate fair value and are classified as Level 1. The estimated fair value of our long-term debt, including current maturities, was $2.5 billion at March 31, 2023 and
December 31, 2022. The estimated fair value of our long-term debt was determined using quoted market prices, and is classified as Level 2.
v3.23.1
VARIABLE INTEREST ENTITES (Notes)
 3 Months Ended
Mar. 31, 2023
Organization, Consolidation and Presentation of Financial Statements [Abstract]  
Variable Interest Entity Disclosure VARIABLE INTEREST ENTITY
KGSS-I is a special-purpose, wholly owned subsidiary of ONE Gas that was formed for the purpose of issuing securitized utility tariff bonds to recover extraordinary costs incurred by Kansas Gas Service resulting from Winter Storm Uri. On November 18, 2022, the securitized financing was complete. KGSS-I’s assets cannot be used to settle ONE Gas’ obligations and the holders of the Securitized Utility Tariff Bonds have no recourse against ONE Gas. See Note 5 for additional information about the securitization financing.

Because KGSS-I’s equity at risk is less than 1 percent of its total assets, it is considered to be a variable interest entity. Through its equity ownership interest and role as servicer, ONE Gas has the power to direct the most significant financial and operating activities of KGSS-I, including billing, collections, and remittance of customer cash receipts to enable KGSS-I to service the principal and interest payments due under the Securitized Utility Tariff Bonds. Therefore, ONE Gas is the primary beneficiary of KGSS-I, and as a result, KGSS-I is included in the consolidated financial statements of ONE Gas. No gain or loss was recognized upon initial consolidation.

The following table summarizes the impact of KGSS-I on our consolidated balance sheets, for the periods indicated:
March 31,December 31,
20232022
(Thousands of dollars)
Restricted cash and cash equivalents$19,117 $8,446 
Accounts receivable4,051 4,862 
Securitized intangible asset, net316,749 323,838 
Current maturities of securitized utility tariff bonds34,497 20,716 
Accounts payable1,374 3,204 
Accrued interest6,810 2,202 
Securitized utility tariff bonds, excluding current maturities, net of issuance costs295,555 309,343 
Equity1,681 1,681 

The following table summarizes the impact of KGSS-I on our consolidated statements of income, for the period indicated:
Three Months Ended
March 31,
2023
(Thousands of dollars)
Operating revenues$11,933 
Operating expense(110)
Amortization expense(7,089)
Interest income75 
Interest expense(4,809)
Income before income taxes$— 
v3.23.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)
 3 Months Ended
Mar. 31, 2023
Significant Accounting Policies [Line Items]  
Segments Segments - We operate in one reportable business segment: regulated public utilities that deliver natural gas primarily to residential, commercial and transportation customers. Our accounting policies are the same as those described in Note 1 of the Notes to Consolidated Financial Statements in our Annual Report. We evaluate our financial performance principally on net income. For the three months ended March 31, 2023 and 2022, we had no single external customer from which we received 10 percent or more of our gross revenues.
Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block] Accounts Receivable - Accounts receivable represent valid claims against nonaffiliated customers for natural gas sold or services rendered, net of allowances for doubtful accounts. We assess the creditworthiness of our customers. Those customers who do not meet minimum standards may be required to provide security, including deposits and other forms of collateral, when appropriate and allowed by our tariffs. With approximately 2.3 million customers across three states, we are not exposed materially to a concentration of credit risk. We maintain an allowance for doubtful accounts based upon factors surrounding the credit risk of customers, historical trends, consideration of the current environment and other information. We recover natural gas costs related to accounts written off when they are deemed uncollectible through the purchased-gas cost adjustment mechanisms in each of our jurisdictions. At March 31, 2023 and December 31, 2022, our allowance for doubtful accounts was $19.7 million and $16.7 million, respectively.
Reclassification, Comparability Adjustment Reclassifications -A reclassification has been made in the prior-year financial statements to conform to the current-year presentation. We have updated our consolidated balance sheet at December 31, 2022, to disaggregate “current maturities of other long-term debt,” which had previously been included in “other current liabilities,” to conform to our current-year presentation.
v3.23.1
DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Policies)
 3 Months Ended
Mar. 31, 2023
Accounting Policies [Abstract]  
Derivatives
Accounting Treatment - We record all derivative instruments at fair value, with the exception of normal purchases and normal sales that are expected to result in physical delivery. The accounting for changes in the fair value of a derivative instrument depends on whether it has been designated and qualifies as part of a hedging relationship and, if so, the reason for holding it, or if regulatory requirements impose a different accounting treatment.

If certain conditions are met, we may elect to designate a derivative instrument as a hedge of exposure to changes in fair values or cash flows. We have not elected to designate any of our derivative instruments as hedges.

The table below summarizes the various ways in which we account for our derivative instruments and the impact on our consolidated financial statements:
  Recognition and Measurement
Accounting Treatment Balance Sheet Income Statement
Normal purchases and
normal sales		-Fair value not recorded-Change in fair value not recognized in earnings
Mark-to-market-Recorded at fair value-Change in fair value recognized in, and recoverable through, the purchased-gas cost adjustment mechanisms
Fair Value Measurement Fair Value Measurements - We define fair value as the price that would be received from the sale of an asset or the transfer of a liability in an orderly transaction between market participants at the measurement date. We use the market and income approaches to determine the fair value of our assets and liabilities and consider the markets in which the transactions are
executed. We measure the fair value of a group of financial assets and liabilities consistent with how a market participant would price the net risk exposure at the measurement date.

Fair Value Hierarchy - At each balance sheet date, we utilize a fair value hierarchy to classify fair value amounts recognized or disclosed in our consolidated financial statements based on the observability of inputs used to estimate such fair value. The levels of the hierarchy are described below:

•Level 1 - Unadjusted quoted prices in active markets for identical assets or liabilities;
•Level 2 - Significant observable pricing inputs other than quoted prices included within Level 1 that are, either directly or indirectly, observable as of the reporting date. Essentially, this represents inputs that are derived principally from or corroborated by observable market data; and
•Level 3 - May include one or more unobservable inputs that are significant in establishing a fair value estimate. These unobservable inputs are developed based on the best information available and may include our own internal data.

We recognize transfers into and out of the levels as of the end of each reporting period.

Determining the appropriate classification of our fair value measurements within the fair value hierarchy requires management’s judgment regarding the degree to which market data is observable or corroborated by observable market data. We categorize derivatives for which fair value is determined using multiple inputs within a single level, based on the lowest level input that is significant to the fair value measurement in its entirety.
v3.23.1
REVENUE (Tables)
 3 Months Ended
Mar. 31, 2023
Revenues Disaggregated by Source [Table]
The following table sets forth our revenues disaggregated by source for the periods indicated:
Three Months Ended
March 31,
20232022
(Thousands of dollars)
Natural gas sales to customers$966,359 $925,157 
Transportation revenues38,527 36,316 
Securitization customer charges (Note 14)11,933 — 
Miscellaneous revenues5,898 4,496 
Total revenues from contracts with customers1,022,717 965,969 
Other revenues - natural gas sales related5,790 2,346 
Other revenues 3,636 3,144 
Total other revenues9,426 5,490 
Total revenues$1,032,143 $971,459 
v3.23.1
REGULATORY ASSETS AND LIABILITIES (Tables)
 3 Months Ended
Mar. 31, 2023
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]  
SCHEDULE OF REGULATED ASSETS AND LIABILITIES
The tables below present a summary of regulatory assets and liabilities, net of amortization, for the periods indicated:
March 31, 2023
CurrentNoncurrentTotal
(Thousands of dollars)
Winter weather event costs$22,633 $28,577 $51,210 
Pension and postemployment benefit costs4,159 243,561 247,720 
Reacquired debt costs812 3,166 3,978 
MGP remediation costs98 29,719 29,817 
Ad-valorem tax11,386 — 11,386 
WNA7,994 — 7,994 
Customer credit deferrals15,475 — 15,475 
Other3,641 3,937 7,578 
Total regulatory assets, net of amortization66,198 308,960 375,158 
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
CurrentNoncurrentTotal
(Thousands of dollars)
Winter weather event costs$221,926 $36,291 $258,217 
Under-recovered purchased-gas costs19,755 — 19,755 
Pension and postemployment benefit costs— 258,257 258,257 
Reacquired debt costs812 3,347 4,159 
MGP remediation costs98 29,743 29,841 
Ad-valorem tax13,359 — 13,359 
WNA8,474 — 8,474 
Customer credit deferrals9,504 — 9,504 
Other1,644 3,193 4,837 
Total regulatory assets, net of amortization275,572 330,831 606,403 
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 
v3.23.1
LONG-TERM DEBT (Tables)
 3 Months Ended
Mar. 31, 2023
Long-Term Debt, Unclassified [Abstract]  
Schedule of Long-Term Debt Instruments
The table below presents a summary of our long-term debt outstanding for the periods indicated:

Interest rate at March 31, 2023
March 31, 2023December 31, 2022
(Thousands of dollars)
Senior unsecured notes:
Senior unsecured notes due February 20243.610%$300,000 $300,000 
Senior unsecured notes due March 20241.100%473,000 473,000 
Senior unsecured notes due May 20302.000%300,000 300,000 
Senior unsecured notes due September 20324.250%300,000 300,000 
Senior unsecured notes due February 20444.658%600,000 600,000 
Senior unsecured notes due November 20484.500%400,000 400,000 
Total senior unsecured notes2,373,000 2,373,000 
KGSS-I Securitized Utility Tariff Bonds5.486%336,000 336,000 
Other8.000%1,247 1,250 
Unamortized discounts on long-term debt(7,531)(7,636)
Debt issuance costs(19,904)(20,143)
Total long-term debt, net2,682,812 2,682,471 
Less: current maturities of securitized utility tariff bonds34,497 20,716 
Less: current maturities of long-term debt772,742 12 
Noncurrent portion of long-term debt, net$1,875,573 $2,661,743 
v3.23.1
Equity (Tables)
 3 Months Ended
Mar. 31, 2023
Equity [Abstract]  
Schedule of Forward Contracts Indexed to Issuer's Equity
Had we settled all shares under our outstanding forward sale agreements as of March 31, 2023, we would have generated net proceeds of approximately $174.4 million, as detailed below:

MaturityShares SoldNet Proceeds Available
(in thousands)		Forward Price
At-the-Market Equity Program
December 29, 2023289,403 $21,748 $75.15 
Equity Forward Agreement
December 29, 20231,400,000 106,863 76.33 
December 31, 2024600,000 45,798 76.33 
Total March 2023 Equity Forward Agreement2,000,000 152,661 76.33 
Total forward sale agreements2,289,403 $174,409 $76.18 
v3.23.1
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)
 3 Months Ended
Mar. 31, 2023
Accumulated Other Comprehensive Income (Loss) [Line Items]  
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]
The following table sets forth the effect of reclassifications from accumulated other comprehensive loss in our consolidated statements of income for the periods indicated:
Three Months EndedAffected Line Item in the
Details About Accumulated OtherMarch 31,Consolidated Statements
Comprehensive Loss Components20232022of Income
(Thousands of dollars)
Pension and other postemployment benefit plan obligations (a)
Amortization of net loss$490 $8,201 
Amortization of unrecognized prior service cost (credit)131 10 
621 8,211 
Regulatory adjustments (b)(621)(8,123)
— 88 Income before income taxes
— (19)Income tax expense
Total reclassifications for the period$— $69 Net income
(a) These components of accumulated other comprehensive loss are included in the computation of net periodic benefit cost. See Note 9 for additional detail of our net periodic benefit cost.
(b) Regulatory adjustments represent pension and other postemployment benefit costs expected to be recovered through rates and are deferred as part of our regulatory assets. See Note 3 for additional disclosures of regulatory assets and liabilities.
v3.23.1
EARNINGS PER SHARE (Tables)
 3 Months Ended
Mar. 31, 2023
EARNINGS PER SHARE [Line Items]  
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] The following tables set forth the computation of basic and diluted EPS from continuing operations for the periods indicated:
Three Months Ended March 31, 2023
IncomeSharesPer Share
Amount
(Thousands, except per share amounts)
Basic EPS Calculation
Net income available for common stock
$102,621 55,538 $1.85 
Diluted EPS Calculation
Effect of dilutive securities— 262 
Net income available for common stock and common stock equivalents$102,621 55,800 $1.84 
Three Months Ended March 31, 2022
IncomeSharesPer Share
Amount
(Thousands, except per share amounts)
Basic EPS Calculation
Net income available for common stock
$98,934 53,922 $1.83 
Diluted EPS Calculation
Effect of dilutive securities— 108 
Net income available for common stock and common stock equivalents$98,934 54,030 $1.83 
v3.23.1
EMPLOYEE BENEFIT PLANS (Tables)
 3 Months Ended
Mar. 31, 2023
Employee Benefit Plans [Line Items]  
Schedule of Net Benefit Costs [Table Text Block]
The following tables set forth the components of net periodic benefit cost for our pension and other postemployment benefit plans for the periods indicated:
Pension Benefits
Three Months Ended
March 31,
20232022
(Thousands of dollars)
Components of net periodic benefit cost (credit)
Service cost$1,811 $3,094 
Interest cost 10,607 7,804 
Expected return on assets (14,879)(14,613)
Amortization of unrecognized prior service cost93 — 
Amortization of net loss 502 8,147 
Net periodic benefit cost (credit)$(1,866)$4,432 

Other Postemployment Benefits
Three Months Ended
March 31,
20232022
(Thousands of dollars)
Components of net periodic benefit cost (credit)
Service cost$183 $318 
Interest cost 2,288 1,612 
Expected return on assets (2,432)(3,295)
Amortization of unrecognized prior service cost38 10 
Amortization of net (gain) loss (12)54 
Net periodic benefit cost (credit)$65 $(1,301)
v3.23.1
OTHER INCOME AND OTHER EXPENSE (Tables)
 3 Months Ended
Mar. 31, 2023
Schedule of Other Nonoperating Income (Expense)
The following table sets forth the components of other income and other expense for the periods indicated:
Three Months Ended
March 31,
20232022
(Thousands of dollars)
Net periodic benefit (cost) credit other than service cost$908 $(588)
Earnings (losses) on investments associated with nonqualified employee benefit plans1,613 (2,833)
Other, net60 (724)
Total other income (expense), net$2,581 $(4,145)
v3.23.1
DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Tables)
 3 Months Ended
Mar. 31, 2023
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]  
Fair Value Measurements, Recurring and Nonrecurring
We record certain financial assets and liabilities at fair value at each balance sheet date. The table below summarizes the balances of these assets at March 31, 2023 and December 31, 2022:
March 31, 2023
Level 1Level 2Total
Other Current Assets:
United States treasury notes$726 $— $726 
Corporate bonds— 2,359 2,359 
Other Assets:
United States treasury notes3,326 — 3,326 
Corporate bonds— 6,913 6,913 

December 31, 2022
Level 1Level 2Total
Other Current Assets:
United States treasury notes$1,204 $— $1,204 
Corporate bonds— 2,086 2,086 
Other Assets:
United States treasury notes3,491 — 3,491 
Corporate bonds— 7,624 7,624 
v3.23.1
VARIABLE INTEREST ENTITES (Tables)
 3 Months Ended
Mar. 31, 2023
Kansas Gas Service Securitization I LLC  
Variable Interest Entity [Line Items]  
Schedule of Variable Interest Entities
The following table summarizes the impact of KGSS-I on our consolidated balance sheets, for the periods indicated:
March 31,December 31,
20232022
(Thousands of dollars)
Restricted cash and cash equivalents$19,117 $8,446 
Accounts receivable4,051 4,862 
Securitized intangible asset, net316,749 323,838 
Current maturities of securitized utility tariff bonds34,497 20,716 
Accounts payable1,374 3,204 
Accrued interest6,810 2,202 
Securitized utility tariff bonds, excluding current maturities, net of issuance costs295,555 309,343 
Equity1,681 1,681 

The following table summarizes the impact of KGSS-I on our consolidated statements of income, for the period indicated:
Three Months Ended
March 31,
2023
(Thousands of dollars)
Operating revenues$11,933 
Operating expense(110)
Amortization expense(7,089)
Interest income75 
Interest expense(4,809)
Income before income taxes$— 
v3.23.1
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)
number in Millions, $ in Millions
 3 Months Ended
Mar. 31, 2023
USD ($)
Mar. 31, 2022
USD ($)
Dec. 31, 2022
USD ($)
Significant Accounting Policies [Line Items]      
Number of natural gas distribution services customers 2.3    
Segment Reporting, Disclosure of Major Customers no no  
Capital Expenditures Incurred but Not yet Paid $ 5.3 $ 8.1  
Allowance for Doubtful Accounts, Premiums and Other Receivables $ 19.7   $ 16.7
v3.23.1
REVENUE (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Dec. 31, 2022
Regulated Operating Revenue, Gas $ 1,022,717 $ 965,969  
Regulated Operating Revenue, Other 9,426 5,490  
Regulated Operating Revenue 1,032,143 971,459  
Unbilled Receivables, Current 146,800   $ 269,500
Natural gas sales to customers [Member]      
Regulated Operating Revenue, Gas 966,359 925,157  
Transportation revenues [Member]      
Regulated Operating Revenue, Gas 38,527 36,316  
Securitization Custoer Charges      
Regulated Operating Revenue, Gas 11,933 0  
Miscellaneous revenues [Member]      
Regulated Operating Revenue, Gas 5,898 4,496  
Other revenues - natural gas sales related [Member]      
Regulated Operating Revenue, Other 5,790 2,346  
Other revenues [Member]      
Regulated Operating Revenue, Other $ 3,636 $ 3,144  
v3.23.1
REGULATORY ASSETS AND LIABILITIES (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Dec. 31, 2022
Feb. 28, 2021
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
Regulatory Assets, Current $ 66,198   $ 275,572  
Regulatory Assets, Noncurrent 308,960   330,831  
Regulatory Assets 375,158   606,403  
Regulatory Liability, Current (48,405)   (47,867)  
Regulatory Liability, Noncurrent (516,625)   (529,441)  
Regulatory Liabilities (565,030)   (577,308)  
Net regulatory assets (liabilities), current 17,793   227,705  
Net regulatory assets (liabilities), noncurrent (207,665)   (198,610)  
Net Regulatory Assets (189,872)   29,095  
February 2021 Natural Gas Purchases       $ 2,100,000
Maximum amount the regulatory asset for the winter storm can be reduced by for collections of penalties assessed on marketers and individually balanced transportation customers 52,600      
Collections of penalties assessed on marketers and individually balanced transportation customers as a result of Winter Storm Uri 51,600      
TGS Proceeds from Securitization Bonds 197,000      
Amortization of Rate Deferral 7,000 $ 4,400    
West Texas Service Area        
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
TGS Deferred Extraordinary Costs from 2021 Winter Storm Uri 36,100      
Pension and postretirement benefit costs [Member]        
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
Regulatory Liability, Current     (8,228)  
Regulatory Liability, Noncurrent     0  
Regulatory Liabilities     (8,228)  
Income tax rate changes [Member] [Domain]        
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
Regulatory Liability, Current 0   0  
Regulatory Liability, Noncurrent (516,625)   (529,441)  
Regulatory Liabilities (516,625)   (529,441)  
Over-recovered purchased-gas costs [Member]        
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
Regulatory Liability, Current (48,405)   (39,639)  
Regulatory Liability, Noncurrent 0   0  
Regulatory Liabilities (48,405)   (39,639)  
Winter weather event costs        
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
Regulatory Assets, Current 22,633   221,926  
Regulatory Assets, Noncurrent 28,577   36,291  
Regulatory Assets 51,210   258,217  
Under-recovered purchased-gas costs [Member]        
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
Regulatory Assets, Current     19,755  
Regulatory Assets, Noncurrent     0  
Regulatory Assets     19,755  
Pension and postretirement benefit costs [Member]        
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
Regulatory Assets, Current 4,159   0  
Regulatory Assets, Noncurrent 243,561   258,257  
Regulatory Assets 247,720   258,257  
Reacquired debt costs [Member]        
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
Regulatory Assets, Current 812   812  
Regulatory Assets, Noncurrent 3,166   3,347  
Regulatory Assets 3,978   4,159  
MGP Costs [Member] [Member]        
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
Regulatory Assets, Current 98   98  
Regulatory Assets, Noncurrent 29,719   29,743  
Regulatory Assets 29,817   29,841  
Ad valorem tax [Member]        
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
Regulatory Assets, Current 11,386   13,359  
Regulatory Assets, Noncurrent 0   0  
Regulatory Assets 11,386   13,359  
Weather normalization [Member]        
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
Regulatory Assets, Current 7,994   8,474  
Regulatory Assets, Noncurrent 0   0  
Regulatory Assets 7,994   8,474  
Customer credit deferrals        
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
Regulatory Assets, Current 15,475   9,504  
Regulatory Assets, Noncurrent 0   0  
Regulatory Assets 15,475   9,504  
Other regulatory assets [Member]        
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]        
Regulatory Assets, Current 3,641   1,644  
Regulatory Assets, Noncurrent 3,937   3,193  
Regulatory Assets $ 7,578   $ 4,837  
v3.23.1
CREDIT FACILITIES (Details)
$ in Thousands
Mar. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Short-term Debt [Line Items]    
Line of Credit Facility, Maximum Borrowing Capacity $ 1,000,000  
Line of Credit Facility Sublimit 20,000  
Bridge Loan 60,000  
Line of Credit Facility Option to Increase Borrowing Capacity $ 500,000  
Approved Debt to Capital Ratio 0.70  
Ratio of Indebtedness to Net Capital 0.53  
Commercial paper maximum borrowing capacity $ 1,000,000  
Commercial Paper $ 280,000 $ 552,000
Short-Term Debt, Weighted Average Interest Rate, at Point in Time 5.41% 4.75%
Letters of Credit Outstanding, Amount $ 1,200  
Line of Credit Facility, Remaining Borrowing Capacity $ 998,800  
v3.23.1
LONG-TERM DEBT (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2023
Dec. 31, 2022
Debt Instrument [Line Items]    
Debt issuance costs $ (7,531) $ (7,636)
Debt Issuance Costs, Net (19,904) (20,143)
Long-Term Debt and Lease Obligation, Including Current Maturities 2,682,812 2,682,471
Current maturities of securitized utility tariff bonds 34,497 20,716
Long-term Debt, Current Maturities 772,742 12
Long-term Debt, including current maturities 1,875,573 2,661,743
Debt Instrument, Covenant Compliance, Default Provision, Indebtnedness Threshold $ 100,000  
Debt Instrument, Covenant Compliance, Default Provision, Debt Holders 25.00%  
Debt Instrument, Redemption Price, Percentage 100.00%  
3.61% Senior Unsecured Notes Due 2024    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 3.61%  
Long-term Debt, Gross $ 300,000 300,000
1.10% Senior Unsecured Notes Due 2024    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 1.10%  
Long-term Debt, Gross $ 473,000 473,000
2.00% Senior Unsecured Notes Due 2024    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 2.00%  
Long-term Debt, Gross $ 300,000 300,000
4.25% Senior Unsecured Notes Due 2032    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.25%  
Long-term Debt, Gross $ 300,000 300,000
4.658% Senior Unsecured Notes Due 2044    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.658%  
Long-term Debt, Gross $ 600,000 600,000
4.50% Senior Unsecured Notes Due 2048    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 4.50%  
Long-term Debt, Gross $ 400,000 400,000
Total Senior Unsecured Notes    
Debt Instrument [Line Items]    
Long-term Debt, Gross $ 2,373,000 2,373,000
5.486% KGSS-I Securitized Utility Tariff Bonds Due 2032    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 5.486%  
Long-term Debt, Gross $ 336,000 336,000
Current maturities of securitized utility tariff bonds $ 34,497 20,716
8.00% Other Long Term Debt    
Debt Instrument [Line Items]    
Debt Instrument, Interest Rate, Stated Percentage 8.00%  
Long-term Debt, Gross $ 1,247 $ 1,250
v3.23.1
EQUITY (Details) - USD ($)
$ / shares in Units, $ in Thousands
 3 Months Ended
Jun. 30, 2023
Mar. 31, 2023
Mar. 31, 2022
Common stock issued, value   $ 435 $ 34,140
Proceeds from Issuance of Common Stock   $ 0 $ 34,468
Forward Contract Indexed to Issuer's Equity, Indexed Shares   2,289,403  
Forward Contract Indexed to Equity, Settlement, Cash, Amount   $ 174,409  
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share   $ 76.18  
Common Stock, Dividends, Per Share, Declared   $ 0.65 $ 0.62
Subsequent Event [Member]      
Common Stock, Dividends, Per Share, Declared $ 0.65    
Common Stock, Dividends, Declared, Annualized Basis $ 2.60    
Dividends Payable, Date of Record May 17, 2023    
Dividends Payable, Date to be Paid Jun. 02, 2023    
At-The-Market Program      
Aggregate Offering Price Limit   $ 300,000  
Common stock issued, shares     403,792
Common stock issued, value     $ 35,000
Proceeds from Issuance of Common Stock     $ 34,700
Equity Available for Issuance   $ 300,000  
Forward Contract Indexed to Issuer's Equity, Indexed Shares   289,403  
Forward Contract Indexed to Equity, Settlement, Cash, Amount   $ 21,748  
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share   $ 75.15  
March 2023 Equity Forward Agreement      
Forward Contract Indexed to Issuer's Equity, Indexed Shares   2,000,000  
Forward Contract Indexed to Equity, Settlement, Cash, Amount   $ 152,661  
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share   $ 76.33  
March 2023 Equity Forward Agreement | December 29, 2023      
Forward Contract Indexed to Issuer's Equity, Indexed Shares   1,400,000  
Forward Contract Indexed to Equity, Settlement, Cash, Amount   $ 106,863  
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share   $ 76.33  
March 2023 Equity Forward Agreement | December 31, 2024      
Forward Contract Indexed to Issuer's Equity, Indexed Shares   600,000  
Forward Contract Indexed to Equity, Settlement, Cash, Amount   $ 45,798  
Forward Contract Indexed to Issuer's Equity, Forward Rate Per Share   $ 76.33  
v3.23.1
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Accumulated Other Comprehensive Income (Loss) [Line Items]    
Amortization of net loss $ 490 $ 8,201
Amortization of unrecognized prior service cost 131 10
Reclassification adjustment, before tax and regulatory adjustments 621 8,211
Regulatory adjustments (621) (8,123)
Reclassification adjustment, before tax 0 88
Reclassification adjustment, Tax 0 (19)
Reclassification adjustment, net of tax $ 0 $ 69
v3.23.1
EARNINGS PER SHARE (Details) - USD ($)
$ / shares in Units, shares in Thousands, $ in Thousands
 3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Basic EPS Calculation    
Net income available for common stock $ 102,621 $ 98,934
Weighted Average Number of Shares Outstanding, Basic 55,538 53,922
Earnings Per Share, Basic $ 1.85 $ 1.83
Diluted EPS Calculation    
Net Income (Loss) Available to Common Stockholders, Diluted $ 102,621 $ 98,934
Effect of dilutive securities on shares 262 108
Weighted Average Number of Shares Outstanding, Diluted 55,800 54,030
Earnings Per Share, Diluted $ 1.84 $ 1.83
v3.23.1
EMPLOYEE BENEFIT PLANS (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Dec. 31, 2022
Components of net periodic benefit cost:      
Amortization of unrecognized prior service cost $ (131) $ (10)  
Amortization of net loss (490) (8,201)  
Capitalized non-service cost components as a regulatory asset 1,400   $ 2,800
ONE Gas Pension Plans [Member]      
Components of net periodic benefit cost:      
Service cost 1,811 3,094  
Interest cost 10,607 7,804  
Expected return on assets (14,879) (14,613)  
Amortization of unrecognized prior service cost 93 0  
Amortization of net loss 502 8,147  
Net periodic benefit cost (1,866) 4,432  
ONE Gas Postretirement Benefit Plans [Member]      
Components of net periodic benefit cost:      
Service cost 183 318  
Interest cost 2,288 1,612  
Expected return on assets (2,432) (3,295)  
Amortization of unrecognized prior service cost 38 10  
Amortization of net loss (12) 54  
Net periodic benefit cost $ 65 $ (1,301)  
v3.23.1
INCOME TAXES (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Income Tax Disclosure [Abstract]    
Reduction in income tax expense for the amortization of the regulatory liability associated with excess ADIT that was returned to customers $ 9.9 $ 7.9
v3.23.1
OTHER INCOME AND OTHER EXPENSE (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2023
Mar. 31, 2022
Other, net $ 2,581 $ (4,145)
Net periodic cost other than service cost [Member]    
Other, net 908 (588)
Earnings (losses) on investments associated with nonqualified employee benefit plans [Member]    
Other, net 1,613 (2,833)
Other, net [Member]    
Other, net $ 60 $ (724)
v3.23.1
COMMITMENTS AND CONTINGENCIES (Details)
$ in Millions
Mar. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Commitments and Contingencies [Line Items]    
Number Of Former Manufactured Gas Sites Where We Own Or Retain Legal Responsibility For Environmental Conditions 12  
Number of sites where regulatory closure has been achieved 5  
Deferred MGP Costs, Maximum $ 15.0  
Regulatory Asset for Costs Associated with Manufactured Gas Sites $ 29.8 $ 29.8
Number of sites with ongoing groundwater monitoring 7  
Accrual for Environmental Loss Contingencies $ 12.7 $ 12.7
v3.23.1
DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Details) Table - USD ($)
$ in Thousands
Mar. 31, 2023
Dec. 31, 2022
Other Current Assets | Corporate Bond Securities    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Financial Instruments, Owned, at Fair Value $ 2,359 $ 2,086
Other Current Assets | Corporate Bond Securities | Fair Value, Inputs, Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Financial Instruments, Owned, at Fair Value 0 0
Other Current Assets | Corporate Bond Securities | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Financial Instruments, Owned, at Fair Value 2,359 2,086
Other Current Assets | US Treasury Securities    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Financial Instruments, Owned, at Fair Value 726 1,204
Other Current Assets | US Treasury Securities | Fair Value, Inputs, Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Financial Instruments, Owned, at Fair Value 726 1,204
Other Current Assets | US Treasury Securities | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Financial Instruments, Owned, at Fair Value 0 0
Other Assets | Corporate Bond Securities    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Financial Instruments, Owned, at Fair Value 6,913 7,624
Other Assets | Corporate Bond Securities | Fair Value, Inputs, Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Financial Instruments, Owned, at Fair Value 0 0
Other Assets | Corporate Bond Securities | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Financial Instruments, Owned, at Fair Value 6,913 7,624
Other Assets | US Treasury Securities    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Financial Instruments, Owned, at Fair Value 3,326 3,491
Other Assets | US Treasury Securities | Fair Value, Inputs, Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Financial Instruments, Owned, at Fair Value 3,326 3,491
Other Assets | US Treasury Securities | Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Financial Instruments, Owned, at Fair Value $ 0 $ 0
v3.23.1
DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Details) Note
$ in Millions
 3 Months Ended
Mar. 31, 2023
USD ($)
Dec. 31, 2022
USD ($)
Bcf
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Derivative, Nonmonetary Notional Amount | Bcf   19.4
Premiums recorded in other current assets on natural gas contracts held   $ 14.1
Fair Value Assets, Transfers between Levels $ 0.0  
Fair Value, Inputs, Level 1 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Fair value, natural gas call options   $ 0.0
Fair Value, Inputs, Level 2 [Member]    
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]    
Long-term Debt, Fair Value $ 2,500.0  
v3.23.1
VARIABLE INTEREST ENTITES (Details) - USD ($)
 3 Months Ended
Mar. 31, 2023
Dec. 31, 2022
Mar. 31, 2022
Dec. 31, 2021
Variable Interest Entity [Line Items]        
Variable Interest Entity, Initial Consolidation, Gain (Loss) $ 0      
Restricted Cash and Cash Equivalents 19,117,000 $ 8,446,000    
Accounts receivable, net 493,573,000 553,834,000    
Current maturities of securitized utility tariff bonds 34,497,000 20,716,000    
Accounts payable 197,619,000 360,493,000    
Stockholders' Equity Attributable to Parent 2,651,480,000 2,584,426,000 $ 2,449,390,000 $ 2,349,532,000
Kansas Gas Service Securitization I LLC        
Variable Interest Entity [Line Items]        
Restricted Cash and Cash Equivalents 19,117,000 8,446,000    
Accounts receivable, net 4,051,000 4,862,000    
Finite-Lived Intangible Assets, Net 316,749,000 323,838,000    
Current maturities of securitized utility tariff bonds 34,497,000 20,716,000    
Accounts payable 1,374,000 3,204,000    
Interest Payable 6,810,000 2,202,000    
Securitized utility tariff bonds 295,555,000 309,343,000    
Stockholders' Equity Attributable to Parent 1,681,000 $ 1,681,000    
Forward Contract Indexed to Equity, Settlement, Cash, Amount 11,933,000      
Utilities Operating Expense (110,000)      
Depreciation and amortization (7,089,000)      
Interest Income, Other 75,000      
Interest Expense (4,809,000)      
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest $ 0