ONE Gas (OGS) 10-K 24 Feb 22 2021 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($)	12 Months Ended
	Dec. 31, 2021	Feb. 21, 2022	Jun. 30, 2021
Document Information [Line Items]
Entity Central Index Key	0001587732
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Amendment Flag	false
Document Type	10-K
Entity Information
City Area Code	(918)
Document Period End Date	Dec. 31, 2021
Current Fiscal Year End Date	--12-31
Document Annual Report	true
Document Transition Report	false
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
Local Phone Number	947-7000
Entity Common Stock, Shares Outstanding		53,633,445
Entity Current Reporting Status	Yes
Entity Emerging Growth Company	false
Entity File Number	001-36108
Entity Incorporation, State or Country Code	OK
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Registrant Name	ONE Gas, Inc.
Entity Tax Identification Number	46-3561936
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Small Business	false
Entity Shell Company	false
Entity Public Float			$ 3,800,000,000
Title of 12(b) Security	Common Stock, par value $0.01 per share
Trading Symbol	OGS
Security Exchange Name	NYSE
ICFR Auditor Attestation Flag	true
Documents Incorporated by Reference [Text Block]	Portions of the definitive proxy statement to be delivered to shareholders in connection with the Annual Meeting of Shareholders to be held May 26, 2022, are incorporated by reference in Part III.

Audit Information

Audit Information	12 Months Ended
	Dec. 31, 2021
Audit Information [Abstract]
Auditor Name	PricewaterhouseCoopers LLP
Auditor Location	Tulsa, Oklahoma
Auditor Firm ID	238

STATEMENTS OF INCOME

STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Revenues	$ 1,808,597	$ 1,530,268	$ 1,652,730
Cost of natural gas	775,006	537,445	687,974
Operating expenses
Operations and maintenance	449,676	431,115	429,126
Depreciation and amortization	207,233	194,881	180,395
General taxes	66,424	63,311	59,977
Total operating expenses	723,333	689,307	669,498
Operating income	310,258	303,516	295,258
Other expense, net	(3,207)	(3,020)	(2,976)
Interest expense, net	(60,301)	(62,505)	(62,681)
Income before income taxes	246,750	237,991	229,601
Income taxes	(40,316)	(41,579)	(42,852)
Net income	$ 206,434	$ 196,412	$ 186,749
Earnings per share
Basic	$ 3.85	$ 3.70	$ 3.53
Diluted	$ 3.85	$ 3.68	$ 3.51
Average shares (thousands)
Basic	53,575	53,133	52,895
Diluted	53,674	53,370	53,240
Dividends declared per share of stock	$ 2.32	$ 2.16	$ 2

STATEMENTS OF COMPREHENSIVE INC

STATEMENTS OF COMPREHENSIVE INCOME STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net income	$ 206,434	$ 196,412	$ 186,749
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Change in pension and other postretirement benefit plans liability, net of tax of $(379), $289, and $479, respectively	1,250	(1,038)	(1,435)
Other comprehensive income (loss), net of tax	1,250	(1,038)	(1,435)
Comprehensive income	207,684	195,374	185,314
Pension and other postretirement benefit plans, Tax	$ (379)	$ 289	$ 479

STATEMENTS OF COMPREHENSIVE I_2

STATEMENTS OF COMPREHENSIVE INCOME (Parentheticals) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Pension and other postretirement benefit plans, Tax	$ (379)	$ 289	$ 479

BALANCE SHEETS

BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Property, plant and equipment
Property, plant and equipment	$ 7,274,268	$ 6,838,603
Accumulated depreciation and amortization	2,083,433	1,971,546
Net property, plant and equipment	5,190,835	4,867,057
Current assets
Cash and cash equivalents	8,852	7,993
Accounts receivable, net	341,756	292,985
Materials and supplies	54,892	52,766
Natural gas in storage	179,646	93,946
Regulatory assets	1,611,676	56,773
Other current assets	27,742	35,406
Total current assets	2,224,564	539,869
Goodwill and other assets
Regulatory assets	724,862	366,956
Goodwill	157,953	157,953
Other assets	103,906	96,877
Total goodwill and other assets	986,721	621,786
Total assets	8,402,120	6,028,712
Equity and long-term debt
Common stock, $0.01 par value: authorized 250,000,000 shares; issued and outstanding 53,633,210 shares at December 31, 2021; issued and outstanding 53,166,733 shares at December 31, 2020	536	532
Paid-in capital	1,790,362	1,756,921
Retained earnings	565,161	483,635
Accumulated other comprehensive income (loss)	(6,527)	(7,777)
Total equity	2,349,532	2,233,311
Long-term debt, excluding current maturities, and net of issuance costs of $12,418 and $13,159, respectively	3,683,378	1,582,428
Total equity and long-term debt	6,032,910	3,815,739
Current liabilities
Notes payable	494,000	418,225
Accounts payable	258,554	152,313
Accrued taxes other than income	67,035	63,800
Customer deposits	62,454	68,028
Regulatory liabilities	8,090	15,761
Other current liabilities	90,360	78,952
Total current liabilities	980,493	797,079
Deferred credits and other liabilities [Abstract]
Deferred Income Taxes	695,284	656,806
Regulatory Liability, Noncurrent	552,928	547,563
Employee benefit obligations	35,226	97,637
Other deferred credits	105,279	113,888
Total deferred credits and other liabilities	1,388,717	1,415,894
Commitments and Contingencies
Total liabilities and equity	$ 8,402,120	$ 6,028,712

BALANCE SHEETS BALANCE SHEETS P

BALANCE SHEETS BALANCE SHEETS Parenthetical - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares Authorized	250,000,000	250,000,000
Common Stock, Shares, Issued	53,674,199	53,166,733
Common Stock, Shares, Outstanding	53,674,199	53,166,733
Debt issuance costs	$ 12,418	$ 13,159

STATEMENTS OF CASH FLOWS

STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Operating activities
Net income	$ 206,434	$ 196,412	$ 186,749
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	207,233	194,881	180,395
Deferred income taxes	43,449	18,485	13,307
Share-based compensation expense	10,498	9,803	9,314
Provision for doubtful accounts	9,131	15,450	8,994
Changes in assets and liabilities:
Accounts receivable	(57,902)	(58,423)	30,415
Materials and supplies	(2,126)	2,966	(11,399)
Natural gas in storage	(85,700)	10,313	3,036
Asset removal costs	(49,029)	(40,833)	(47,784)
Accounts payable	107,207	28,376	(59,293)
Accrued taxes other than income	3,235	15,844	316
Customer deposits	(5,574)	10,041	(3,196)
Increase Decrease In Regulatory Assets And Liabilities Current	(1,562,574)	(38,773)	3,787
Increase Decrease In Regulatory Assets And Liabilities Non-current	(367,210)	23,648	24,416
Employee benefit obligation	0	(3,109)	(35,401)
Increase (Decrease) in Other Current Assets and Liabilities, Net	18,461	(12,877)	7,173
Increase (Decrease) in Other Noncurrent Assets and Liabilities, Net	(11,190)	(7,704)	(484)
Cash provided by operating activities	(1,535,657)	364,500	310,345
Investing activities
Capital expenditures	(495,246)	(471,345)	(417,322)
Payments to Acquire Assets, Investing Activities	(7,554)	(2,804)	(7,009)
Proceeds from Sale of Other Assets, Investing Activities	1,717	3,777	1,399
Cash used in investing activities	(501,083)	(470,372)	(422,932)
Financing activities
Borrowings (repayment) on notes payable, net	75,775	(98,275)	217,000
Proceeds from Issuance of Long-term Debt	2,498,895	298,428	0
Payments of Financing Costs	(35,110)	(2,885)	0
Issuance of common stock	26,662	19,383	5,116
Repayments of Long-term Debt	(400,000)	0	0
Dividends paid	(123,912)	(114,372)	(105,424)
Tax withholdings related to net share settlements of stock compensation	(4,711)	(6,267)	(7,575)
Cash provided by (used in) financing activities	2,037,599	96,012	109,117
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Excluding Exchange Rate Effect, Total	859	(9,860)	(3,470)
Cash and cash equivalents at beginning of period	7,993	17,853	21,323
Cash and cash equivalents at end of period	8,852	7,993	17,853
Supplemental cash flow information:
Interest Paid, Excluding Capitalized Interest, Operating Activities	70,066	60,126	61,160
Cash received for income taxes, net	$ (10,809)	$ 30,361	$ 30,152

STATEMENT OF CHANGES IN EQUITY

STATEMENT OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Additional Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Common Stock, Shares, Issued	52,598,005
Common Stock, Dividends, Declared, Annualized Basis	$ 2
Equity, beginning balance at Dec. 31, 2018	$ 2,042,656	$ 526	$ 1,727,492	$ 320,869	$ (2,145)	$ (4,086)
Net income	186,749	0	0	186,749	0	0
Other comprehensive loss	(1,435)	0	0	0	0	(1,435)
Income Tax Effects Allocated Directly to Equity, Cumulative Effect of Change in Accounting Principle	$ 0	0	0	1,218	0	(1,218)
Common stock issued, shares	173,744
Common stock issued, value	$ 6,844	2	4,697	0	2,145	0
Common stock dividends	(105,424)	0	903	(106,327)	0	0
Equity, ending balance at Dec. 31, 2019	$ 2,129,390	528	1,733,092	402,509	0	(6,739)
Common Stock, Shares, Issued	52,771,749
Common Stock, Dividends, Declared, Annualized Basis	$ 2.16
Net income	$ 196,412	0	0	196,412	0	0
Other comprehensive loss	$ (1,038)	0	0	0	0	(1,038)
Common stock issued, shares	394,984
Common stock issued, value	$ 22,919	4	22,915	0	0	0
Common stock dividends	(114,372)	0	914	(115,286)	0	0
Equity, ending balance at Dec. 31, 2020	$ 2,233,311	$ 532	1,756,921	483,635	0	(7,777)
Common Stock, Shares, Issued	53,166,733	(53,166,733)
Common Stock, Dividends, Declared, Annualized Basis	$ 2.32
Net income	$ 206,434	$ 0	0	206,434	0	0
Other comprehensive loss	$ 1,250	0	0	0	0	1,250
Common stock issued, shares	466,477
Common stock issued, value	$ 32,449	4	32,445	0	0	0
Common stock dividends	(123,912)	0	996	(124,908)	0	0
Equity, ending balance at Dec. 31, 2021	$ 2,349,532	$ 536	$ 1,790,362	$ 565,161	$ 0	$ (6,527)
Common Stock, Shares, Issued	53,674,199	(53,633,210)

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Notes)	12 Months Ended
	Dec. 31, 2021
Significant Accounting Policies [Line Items]
SIGNIFICANT ACCOUNTING POLICIES	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization and Nature of Operations - We provide natural gas distribution services to our approximately 2.2 million customers through our divisions in Oklahoma, Kansas and Texas through Oklahoma Natural Gas, Kansas Gas Service and Texas Gas Service, respectively. We primarily serve residential, commercial and transportation customers in all three states. We are a corporation incorporated under the laws of the state of Oklahoma, and our common stock is listed on the NYSE under the trading symbol “OGS.” Basis of Presentation - The consolidated financial statements include the accounts of our natural gas distribution business as set forth in “Organization and Nature of Operations” above. All significant balances and transactions between our subsidiaries have been eliminated. Use of Estimates - The preparation of our consolidated financial statements and related disclosures in accordance with GAAP requires us to make estimates and assumptions with respect to values or conditions that cannot be known with certainty that affect the reported amount of assets and liabilities, and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements. These estimates and assumptions also affect the reported amounts of revenue and expenses during the reporting period. Items that may be estimated include, but are not limited to, the economic useful life of assets, fair value of assets and liabilities, provisions for doubtful accounts receivable, unbilled revenues for natural gas delivered but for which meters have not been read, natural gas purchased but for which no invoice has been received, provision for income taxes, including any deferred income tax valuation allowances, the results of litigation and various other recorded or disclosed amounts. We evaluate these estimates on an ongoing basis using historical experience and other methods we consider reasonable based on the particular circumstances. Nevertheless, actual results may differ significantly from the estimates. Any effects on our financial position or results of operations from revisions to these estimates are recorded in the period when the facts that give rise to the revision become known. Revenues - We recognize revenue from contracts with customers to depict the transfers of goods and services to customers at an amount that we expect to be entitled to receive in exchange for these goods and services. Our sources of revenue are disaggregated by natural gas sales, transportation revenues, and miscellaneous revenues, which are primarily one-time service fees, that meet the requirements of ASC 606. Certain revenues that do not meet the requirements of ASC 606 are classified as other revenues in our Notes to Consolidated Financial Statements in this Annual Report. Our natural gas sales to customers and transportation revenues represent revenues from contracts with customers through implied contracts established by our tariffs approved by the regulatory authorities. Our customers receive the benefits of our performance when the commodity is delivered to the customer. The performance obligation is satisfied over time as the customer receives the natural gas. For deliveries of natural gas, we read meters and bill customers on a monthly cycle. We recognize revenues upon the delivery of natural gas commodity or services rendered to customers. The billing cycles for customers do not necessarily coincide with the accounting periods used for financial reporting purposes. We accrue unbilled revenues for natural gas that has been delivered but not yet billed at the end of an accounting period. We use the invoice method practical expedient, where we recognize revenue for volumes delivered for which we have a right to invoice. Our estimate of accrued unbilled revenue is based on a percentage estimate of amounts unbilled each month, which is dependent upon a number of factors, some of which require management’s judgment. These factors include customer consumption patterns and the impact of weather on usage. The accrued unbilled natural gas sales revenue at December 31, 2021 and 2020 was $183.2 million and $144.9 million, respectively, and is included in accounts receivable on our consolidated balance sheets. Our miscellaneous revenues from contracts with customers represent implied contracts established by our tariff rates approved by the regulatory authorities and include miscellaneous utility services with the performance obligation satisfied at a point in time when services are rendered to the customer. Total other revenues consist of revenues associated with regulatory mechanisms that do not meet the requirements of ASC 606 as revenue from contracts with customers, but authorize us to accrue revenues earned based on tariffs approved by the regulatory authorities. Other revenues - natural gas sales primarily relate to the WNA mechanism in Kansas. This mechanism adjusts our revenues earned for the variance between actual and normal HDDs. This mechanism can have either positive (warmer than normal) or negative (colder than normal) effects on revenues. We collect and remit other taxes on behalf of governmental authorities, and we record these amounts in accrued taxes other than income in our consolidated balance sheets. See Note 2 for additional discussion of revenues. Cost of Natural Gas - Cost of natural gas includes commodity purchases, fuel, storage, transportation and other gas purchase costs recovered through our cost of natural gas regulatory mechanisms and does not include an allocation of general operating costs or depreciation and amortization. These cost of natural gas regulatory mechanisms provide a method of recovering natural gas costs on an ongoing basis without a profit. See Note 10 for additional discussion of purchased gas cost recoveries. Cash and Cash Equivalents - Cash equivalents consist of highly liquid investments, which are readily convertible into cash and have original maturities of three months or less. Accounts Receivable - Accounts receivable represent valid claims against nonaffiliated customers for natural gas sold or services rendered, net of an allowance 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 2.2 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 credit environment and other information. We are able to recover natural gas costs related to uncollectible accounts through purchased-gas cost adjustment mechanisms. At December 31, 2021 and 2020, our allowance for doubtful accounts was $18.7 million and $16.6 million, respectively. Inventories - Natural gas in storage is accounted for on the basis of weighted-average cost. Natural gas inventories that are injected into storage are recorded in inventory based on actual purchase costs, including storage and transportation costs. Natural gas inventories that are withdrawn from storage are accounted for in our purchased-gas cost adjustment mechanisms at the weighted-average inventory cost. Materials and supplies inventories are stated at the lower of weighted-average cost or net realizable value. Leases - We determine if an arrangement is a lease at inception if the contract conveys the right to control the use and obtain substantially all the economic benefits from the use of an identified asset for a period of time in exchange for consideration. We identify a lease as a finance lease if the agreement includes any of the following criteria: transfer of ownership by the end of the lease term; an option to purchase the underlying asset that the lessee is reasonably certain to exercise; a lease term that represents 75 percent or more of the remaining economic life of the underlying asset; a present value of lease payments and any residual value guaranteed by the lessee that equals or exceeds 90 percent of the fair value of the underlying asset; or an underlying asset that is so specialized in nature that there is no expected alternative use to the lessor at the end of the lease term. A lease that does not meet any of these criteria is considered an operating lease. Lease right-of-use assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Right-of-use assets and liabilities are recognized at the commencement date of a lease based on the present value of lease payments over the lease term. Our lease terms may include options to extend or terminate the lease. We include these extension or termination options in the determination of the lease term when it is reasonably certain that we will exercise that option. We have lease agreements with lease and non-lease components, which are accounted for separately. Additionally, for certain office equipment leases, we apply a portfolio approach to effectively account for the operating lease right-of-use assets and liabilities. We do not recognize leases having a term of less than one year in our consolidated balance sheets. For purposes of determining the present value of the lease payments, we use a lease’s implicit interest rate when readily determinable. As most of our leases do not provide an implicit interest rate, we use an incremental borrowing rate based on available information at the commencement of the lease. Lease cost for operating leases is recognized on a straight-line basis over the lease term. See Note 5 for additional information regarding our leases. Derivatives and Risk Management Activities - 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 - 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 See Note 9 for additional information regarding our hedging activities using derivatives. 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. See Note 9 for additional information regarding our fair value measurements. Property, Plant and Equipment - Our properties are stated at cost, which includes direct construction costs such as direct labor, materials, burden and AFUDC. Generally, the cost of our property retired or sold, plus removal costs, less salvage, is charged to accumulated depreciation. Gains and losses from sales or retirement of an entire operating unit or system of our properties are recognized in income. Maintenance and repairs are charged directly to expense. AFUDC represents the cost of borrowed funds used to finance construction activities. We capitalize interest costs during the construction or upgrade of qualifying assets. Capitalized interest is recorded as a reduction to interest expense. Our properties are depreciated using the straight-line method over their estimated useful lives. Generally, we apply composite depreciation rates to functional groups of property having similar economic circumstances. We periodically conduct depreciation studies to assess the economic lives of our assets. These depreciation studies are completed as a part of our regulatory proceedings, and the changes in economic lives, if applicable, are implemented prospectively when the new rates are approved by our regulators and become effective. Changes in the estimated economic lives of our property, plant and equipment could have a material effect on our financial position, results of operations or cash flows. Property, plant and equipment on our Consolidated Balance Sheets includes construction work in process for capital projects that have not yet been placed in service and therefore are not being depreciated. Assets are transferred out of construction work in process when they are substantially complete and ready for their intended use. See Note 11 for additional information regarding our property, plant and equipment. Impairment of Goodwill and Long-Lived Assets - We assess our goodwill for impairment at least annually as of July 1, unless events or a change in circumstances indicate an impairment may have occurred before that time. As part of our goodwill impairment test, we first assess qualitative factors (including macroeconomic conditions, industry and market considerations, cost factors and overall financial performance) to determine whether it is more likely than not that our fair value is less than the carrying amount of our net assets. If further testing is necessary or a quantitative test is elected to refresh our recurring qualitative assessment, we perform a quantitative impairment test for goodwill. Our impairment test is made by comparing our fair value with our book value, including goodwill. If the fair value is less than the book value, an impairment is measured by the amount of our carrying value that exceeds fair value, not to exceed the carrying amount of our goodwill. To estimate fair value, we use two generally accepted valuation approaches, an income approach and a market approach, using assumptions consistent with a market participant’s perspective. Under the income approach, we use anticipated cash flows over a period of years plus a terminal value and discount these amounts to their present value using appropriate discount rates. Under the market approach, we apply acquisition multiples to forecasted cash flows. The acquisition multiples used are consistent with historical market transactions. The forecasted cash flows are based on average forecasted cash flows over a period of years. We performed a quantitative analysis in 2019, which did not result in any impairment indicators, nor did our analysis reflect our reporting unit at risk. Our goodwill impairment analysis performed in 2021 and 2020 utilized a qualitative assessment and did not result in any impairment indicators, nor did our analysis reflect our reporting unit at risk. Subsequent to July 1, 2021, no event has occurred indicating that it is more likely than not that our fair value is less than the carrying value of our net assets. We assess our long-lived assets for impairment whenever events or changes in circumstances indicate that an asset’s carrying amount may not be recoverable. An impairment is indicated if the carrying amount of a long-lived asset exceeds the sum of the undiscounted future cash flows expected to result from the use and eventual disposition of the asset. If an impairment is indicated, we record an impairment loss equal to the difference between the carrying value and the fair value of the long-lived asset. We determined that there were no material asset impairments in 2021, 2020 or 2019. Regulation - We are subject to the rate regulation and accounting requirements of the OCC, KCC, RRC and various municipalities in Texas. We follow the accounting and reporting guidance for regulated operations. During the ratemaking process, regulatory authorities set the framework for what we can charge customers for our services and establish the manner that our costs are accounted for, including allowing us to defer recognition of certain costs and permitting recovery of the amounts through rates over time, as opposed to expensing such costs as incurred. Examples include weather normalization, unrecovered purchased-gas costs, extraordinary costs associated with Winter Storm Uri, pension and postemployment benefit costs and ad-valorem taxes. This allows us to stabilize rates over time rather than passing such costs on to the customer for immediate recovery. Actions by regulatory authorities could have an effect on the amount recovered from customers. Any difference in the amount recoverable and the amount deferred is recorded as income or expense at the time of the regulatory action. A write-off of regulatory assets and costs not recovered may be required if all or a portion of the regulated operations have rates that are no longer: • established by independent regulators; • designed to recover our costs of providing regulated services; and • set at levels that will recover our costs when considering the demand and competition for our services. See Note 10 for additional information regarding our regulatory assets and liabilities disclosures. Pension and Other Postemployment Employee Benefits - We have defined benefit pension plans covering eligible employees. We also sponsor welfare plans that provide other postemployment medical and life insurance benefits to eligible employees who retire with at least five years of service. To calculate the costs and liabilities related to our plans, we utilize an outside actuarial consultant, which uses statistical and other factors to anticipate future events. These factors include assumptions about the discount rate, expected return on plan assets, rate of future compensation increases, age and mortality and employment periods. We use tables issued by the Society of Actuaries to estimate mortality rates. In determining the projected benefit obligations and costs, assumptions can change from period to period and may result in material changes in the cost and liabilities we recognize. Income Taxes - Deferred income taxes are recorded for the difference between the financial statement and income tax basis of assets and liabilities and carryforward items, based on income tax laws and rates existing at the time the temporary differences are expected to reverse. The effect on deferred income taxes of a change in tax rates is deferred and amortized for operations regulated by the OCC, KCC, RRC and various municipalities in Texas, if, as a result of an action by a regulator, it is probable that the effect of the change in tax rates will be recovered from or returned to customers through future rates. We continue to amortize previously deferred investment tax credits for ratemaking purposes over the periods prescribed by our regulators. A valuation allowance for deferred income tax assets is recognized when it is more likely than not that some or all of the benefit from the deferred income tax asset will not be realized. To assess that likelihood, we use estimates and judgment regarding our future taxable income, as well as the jurisdiction in which such taxable income is generated, to determine whether a valuation allowance is required. Such evidence can include our current financial position, our results of operations, both actual and forecasted, the reversal of deferred income tax liabilities, as well as the current and forecasted business economics of our industry. We had no valuation allowance at December 31, 2021 and 2020. We utilize a more-likely-than-not recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position that is taken or expected to be taken in a tax return. We reflect penalties and interest as part of income tax expense as they become applicable for tax provisions that do not meet the more-likely-than-not recognition threshold and measurement attribute. There were no material uncertain tax positions at December 31, 2021 and 2020. Changes in tax laws or tax rates are recognized in the financial reporting period that includes the enactment date. See Note 14 for additional information regarding income taxes. Asset Retirement Obligations - Asset retirement obligations represent legal obligations associated with the retirement of long-lived assets that result from the acquisition, construction, development and/or normal use of the asset. Certain long-lived assets that comprise our natural gas distribution systems, primarily our pipeline assets, are subject to agreements or regulations that give rise to an asset retirement obligation for removal or other disposition costs associated with retiring the assets in place upon the discontinued use of the natural gas distribution system. We recognize the fair value of a liability for an asset retirement obligation in the period when it is incurred if a reasonable estimate of the fair value can be made. We are not able to estimate reasonably the fair value of the asset retirement obligations for portions of our assets because the settlement dates are indeterminable given our expected continued use of the assets with proper maintenance. We expect our natural gas distribution systems will continue in operation for the foreseeable future. Based on our proximity to significant natural gas reserves and infrastructure and the widespread use of natural gas for heating and cooking activities by residential and commercial customers in our service areas, we expect supply and demand to exist for the foreseeable future. In accordance with long-standing regulatory treatment, we collect through rates the estimated costs of removal on certain regulated properties through depreciation expense as a portion of the net salvage value component of our composite deprecation rates, with a corresponding credit to accumulated depreciation and amortization. These removal costs collected through our rates include costs attributable to legal and nonlegal removal obligations. These costs are addressed prospectively in depreciation rates, rather than as a regulatory liability, in each general rate order. For financial reporting purposes, if the removal costs collected have exceeded our removal costs incurred, we estimate a regulatory liability using current rates since the last general rate order in each of our jurisdictions. At December 31, 2021 and 2020, we have not recorded a regulatory liability as our removal costs incurred have exceeded amounts collected through our depreciation rates. Significant uncertainty exists regarding the recording of these regulatory liabilities, pending, among other issues, clarification of regulatory intent. We continue to monitor the regulatory requirements, and any future regulatory liabilities incurred may be adjusted as more information is obtained. To the extent these estimated liabilities are adjusted, such amounts will be reclassified between accumulated depreciation and amortization and regulatory liabilities on our balance sheet and therefore will not have an impact on earnings. Contingencies - Our accounting for contingencies covers a variety of business activities, including contingencies for legal and environmental exposures. We accrue these contingencies when our assessments indicate that it is probable that a liability has been incurred or an asset will not be recovered and an amount can be estimated reasonably. We expense legal fees as incurred and base our legal liability estimates on currently available facts and our estimates of the ultimate outcome or resolution. Accruals for the estimated cost of environmental remediation obligations generally are recognized no later than the completion of a remediation feasibility study. Recoveries of environmental remediation costs from other parties are recorded as assets when their receipt is deemed probable. Actual results may differ from our estimates resulting in an impact, positive or negative, on earnings. See Note 16 for additional information regarding contingencies. Share-Based Payments - We expense the fair value of share-based payments net of estimated forfeitures. We estimate forfeiture rates based on historical forfeitures under our share-based payment plans. Earnings per share - Basic EPS is based on net income and is calculated based upon the daily weighted-average number of common shares outstanding during the periods presented. Also, this calculation includes fully vested stock awards that have not yet been issued as common stock. Diluted EPS includes the above, plus unvested stock awards granted under our compensation plans, but only to the extent these instruments dilute earnings per share. Segments - We operate in one reportable business segment: regulated public utilities that deliver natural gas primarily to residential, commercial and transportation customers. We define reportable business segments as components of an organization for which discrete financial information is available and operating results are evaluated on a regular basis by the chief operating decision maker (“CODM”) in order to assess performance and allocate resources. Our CODM is our Chief Executive Officer. Characteristics of our organization that were relied upon in making this determination include the similar nature of services we provide, the functional alignment of our organizational structure, and the reports that are regularly reviewed by the CODM for the purpose of assessing performance and allocating resources. Our management is functionally aligned and centralized, with performance evaluated based upon results of the entire distribution business. Capital allocation decisions are driven by asset integrity management, operating efficiency, growth opportunities and government-requested pipeline relocations, not geographic location or regulatory jurisdiction. In 2021, 2020 and 2019, we had no single external customer from which we received 10 percent or more of our gross revenues. Treasury Stock - We record treasury stock purchases at cost, which includes incremental direct transaction costs. Amounts are recorded as reductions in equity in our consolidated balance sheets. We record the reissuance of treasury stock at our weighted average cost of treasury shares recorded in equity in our consolidated balance sheets. Reclassifications - Certain reclassifications have been made in the prior-year financial statements to conform to the current-year presentation. We have updated our 2020 and 2019 Statements of Cash Flows to disaggregate “regulatory assets and liabilities” and “other assets and liabilities” into current and non-current components that are presented on our balance sheet to conform to our current year presentation. Recently Issued Accounting Standards Update - In March 2020, the FASB issued ASU 2020-04, “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting,” which provides relief from the accounting analysis and impacts that may otherwise be required for modifications to agreements (e.g., loans, debt securities, derivatives, borrowings) necessitated by reference rate reform. It also provides optional expedients to enable companies to continue to apply hedge accounting to certain hedging relationships impacted by reference rate reform. In the first quarter 2020, we adopted this new guidance effective for contracts modified between March 12, 2020 and December 31, 2022. Our revolving line of credit under the ONE Gas Credit Agreement and our floating-rate senior notes utilize LIBOR as the reference rate. If modified, we may elect the optional practical expedients to account for the modifications prospectively. Our adoption did not result in a material impact to our consolidated financial statements. In December 2019, the FASB issued ASU 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes,” which removes certain exceptions for recognizing deferred taxes for investments, performing intra-period allocation and calculating income taxes in interim periods. ASU 2019-12 also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. This standard is effective for interim and annual periods in fiscal years beginning after December 15, 2020. We adopted this new guidance in the first quarter of 2021 and our adoption did not result in a material impact to our financial position or results of operations or to our consolidated financial statements. In August 2018, the FASB issued ASU 2018-15, “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (a consensus of the FASB Emerging Issues Task Force).” Under this guidance, a company should defer implementation costs that it incurs if a company would capitalize those same costs under the internal-use software guidance for an arrangement that is a software license. The deferred implementation costs should be amortized over the term of the hosting arrangement, including any probable renewals. We are party to hosting arrangements identified as service contracts for various information systems used in our operations. We adopted this new guidance using the prospective transition approach for implementation costs incurred in hosting arrangement service contracts beginning January 1, 2020. In certain jurisdictions, we have orders from our regulators allowing us to amortize deferred implementation costs for hosting arrangements entered into after January 1, 2020, over the life approved by our regulators for our internal-use software systems rather than the term of the hosting arrangement. The difference in amortization calculated between the term of the hosting arrangement and internal-use software life approved by our regulators is deferred as a regulatory asset and amortized over the remaining internal-use software life that exceeds the term of the hosting arrangement. Our adoption did not result in a material impact to our consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-14, an amendment to ASC 715, “Compensation - Retirement Benefits.” This guidance eliminates requirements for certain disclosures such as the amount and timing of plan assets expected to be returned to the employer and the amount of future annual benefits covered by insurance contracts. The standard is effective for periods ending afte

REVENUE (Notes)

REVENUE (Notes)	12 Months Ended
	Dec. 31, 2021
Revenue [Policy Text Block]	REVENUE The following table sets forth our revenues disaggregated by source for the periods indicated: Year Ended December 31, 2021 2020 2019 (Thousands of dollars) Natural gas sales to customers $ 1,652,566 $ 1,381,141 $ 1,512,886 Transportation revenues 118,492 113,855 114,014 Miscellaneous revenues 16,757 15,505 20,579 Total revenues from contracts with customers 1,787,815 1,510,501 1,647,479 Other revenues - natural gas sales related 9,650 8,299 (4,699) Other revenues 11,132 11,468 9,950 Total other revenues 20,782 19,767 5,251 Total revenues $ 1,808,597 $ 1,530,268 $ 1,652,730

CREDIT FACILITY AND SHORT-TERM

CREDIT FACILITY AND SHORT-TERM NOTES PAYABLE (Notes)	12 Months Ended
	Dec. 31, 2021
Short-term Debt [Line Items]
Short-term Debt [Text Block]	CREDIT FACILITY AND SHORT-TERM NOTES PAYABLE On March 16, 2021, we entered into the second amended and restated ONE Gas Credit Agreement, which was previously amended and restated on October 5, 2017. 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. We will be able to extend the maturity date by one year, subject to the lenders’ consent, up to two times. The ONE Gas Credit Agreement expires in March 2026, and 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 utilizes LIBOR as the reference rate for determining interest to accrue on the borrowings. In the event LIBOR is not available, and such circumstances are unlikely to be temporary, our lenders may establish an alternative interest rate for the senior notes by replacing LIBOR with one or more secured overnight financing-based rates or another alternate benchmark rate. 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 72.5 percent at the end of any calendar quarter through December 31, 2021, and 70 percent at the end of any calendar quarter thereafter. At December 31, 2021, our total debt-to-capital ratio was 64 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 December 31, 2021, 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 available to repay our commercial paper borrowings. In connection with the second amendment and restatement of the ONE Gas Credit Agreement on March 16, 2021, all commitments under the ONE Gas 364-day Credit Agreement were terminated and all obligations under the ONE Gas 364-day Credit Agreement were discharged. On June 22, 2021, we increased the size of our commercial paper program to permit the issuance of commercial paper to fund short-term borrowing needs in an aggregate principal amount not to exceed $1.0 billion outstanding at any time. The maturities of the commercial paper notes may vary, but may not exceed 270 days from the date of issue. The commercial paper notes are sold generally at par less a discount representing an interest factor. At December 31, 2021 and 2020, we had $494.0 million and $418.2 million of commercial paper outstanding, respectively. The weighted-average interest rate on our commercial paper was 0.38 percent and 0.18 percent at December 31, 2021 and 2020, respectively.

LONG-TERM DEBT (Notes)

LONG-TERM DEBT (Notes)	12 Months Ended
	Dec. 31, 2021
Debt Instrument [Line Items]
Long-term Debt [Text Block]	LONG-TERM DEBT Senior Notes - In March 2021, we issued $1.0 billion of 0.85 percent senior notes due 2023, $700 million of 1.10 percent senior notes due 2024, and $800 million of floating-rate senior notes due 2023. The floating-rate senior notes bear interest at a rate equal to three-month LIBOR plus 61 basis points per year reset quarterly for the applicable interest period (0.81 percent at December 31, 2021). The net proceeds from the issuance were used for general corporate purposes, including payment of gas purchase costs resulting from Winter Storm Uri. In the event LIBOR is not available, and such circumstances are unlikely to be temporary, we or our designee may establish an alternative interest rate for our floating-rate senior notes due 2023 by replacing LIBOR with one or more secured financing-based rates or another alternate benchmark rate. On September 21, 2021, we called $400 million of the floating-rate senior notes due 2023 at par, using a combination of cash on hand and commercial paper. We did not have the right to call these senior notes prior to September 11, 2021. In April 2020, ONE Gas issued $300 million of 2.00 percent senior notes due 2030. The proceeds from the issuance were used to reduce the amount of outstanding commercial paper and for general corporate purposes. Our long-term debt includes $1.0 billion of 0.85 percent senior notes due 2023, $400 million of floating-rate senior notes due 2023, $300 million of 3.61 percent senior notes due in 2024, $700 million of 1.10 percent senior notes due 2024, $300 million of 2.00 percent senior notes due 2030, $600 million of 4.658 percent senior notes due 2044, and $400 million of 4.50 percent senior notes due 2048. 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 the 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. ONE Gas 2021 Term Loan Facility - On February 22, 2021, we entered into the ONE Gas 2021 Term Loan Facility as part of the financing of our natural gas purchases in order to provide sufficient liquidity to satisfy our obligations as a result of Winter Storm Uri. The net proceeds of the March 2021 debt issuance reduced the commitments under the ONE Gas 2021 Term Loan Facility on a dollar-for-dollar basis, and as a result no commitments remained outstanding and the facility was terminated concurrently with the closing of the debt issuance.

LEASES (Notes)

LEASES (Notes)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Lessee, Operating Leases [Text Block]	LEASES We have operating leases for office facilities, gas storage facilities, IT equipment and right-of-way contracts. Our leases have remaining lease terms of one year to eight years, some of which include options to extend the leases for up to 10 years, and some of which include options to terminate the leases within specified time frames. We have not entered into any finance leases. Our right-of-use asset is $30.9 million and $37.2 million as of December 31, 2021 and 2020, respectively, and is reported within other assets in our Consolidated Balance Sheets. Operating lease liabilities are reported within our other current liabilities and other liabilities in our consolidated balance sheets. Total operating lease cost including immaterial amounts attributable to short-term operating leases was $8.2 million, $8.4 million, and $8.5 million in 2021, 2020 and 2019, respectively. In 2021, we reassessed certain operating leases for office facilities and IT which were extended or modified, resulting in an increase in our right-of-use asset and operating lease liability of $0.4 million and $0.4 million, respectively. Years Ended December 31, Other information related to operating leases 2021 2020 2019 (Millions of dollars) Weighted-average remaining lease term 6 years 7 years 7 years Weighted-average discount rate 2.78 % 2.81 % 3.62 % Supplemental cash flows information Lease payments $ (8.0) $ (8.0) $ (8.4) Right-of-use assets obtained in exchange for lease obligations $ 0.4 $ 9.8 $ 9.5 December 31, Future minimum lease payments under non-cancellable operating leases 2021 (Millions of dollars) 2022 $ 7.5 2023 6.3 2024 4.8 2025 4.1 2026 3.3 Thereafter 7.7 Total future minimum lease payments $ 33.7 Imputed interest (2.5) Total operating lease liability $ 31.2 Consolidated balance sheets as of December 31, 2021 Current operating lease liability $ 6.8 Long-term operating lease liability 24.4 Total operating lease liability $ 31.2

EQUITY (Notes)

EQUITY (Notes)	12 Months Ended
	Dec. 31, 2021
Class of Stock [Line Items]
Stockholders' Equity Note Disclosure [Text Block]	EQUITY Preferred Stock - At December 31, 2021, we had 50 million, $0.01 par value, authorized shares of preferred stock available. We have not issued or established any classes or series of shares of preferred stock. Common Stock - At December 31, 2021, we had approximately 196.4 million shares of authorized common stock available for issuance. Treasury Shares - In 2019, we were authorized to purchase treasury shares to be used to offset shares issued under our equity compensation plan and the ESPP. Our Board of Directors established an annual limit of $20 million of treasury stock purchases, exclusive of funds received through the dividend reinvestment and the ESPP. Stock purchases could have been made in the open market or in private transactions at times, and in amounts that we deemed appropriate. There was no guarantee as to the exact number of shares that we would have purchased, and we terminated the program in 2019. At-the-Market Equity Program - In February 2020, we initiated an at-the-market equity program by entering into an equity distribution agreement under which we may issue and sell shares of our common stock with an aggregate offering price up to $250 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). 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. For the years ended December 31, 2021 and 2020, we issued and sold 281,124 and 179,514 shares of our common stock for $21.4 million and $13.6 million, respectively, generating proceeds, net of issuance costs, of $21.1 million and $13.5 million, respectively. At December 31, 2021, we had $215.0 million of equity available for issuance under the program. Dividends Declared - For the years ended December 31, 2021 and 2020, we declared and paid dividends of 2.32 per share (0.58 per share quarterly) and 2.16 per share (0.54 per share quarterly), respectively. In January 2022, we declared a dividend of $0.62 per share ($2.48 per share on an annualized basis) for shareholders of record on February 25, 2022, payable on March 11, 2022.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Notes)	12 Months Ended
	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Comprehensive Income (Loss) Note [Text Block]	ACCUMULATED OTHER COMPREHENSIVE LOSS The following table sets forth the balance in accumulated other comprehensive loss for the periods indicated: Accumulated Other Comprehensive Loss (Thousands of dollars) January 1, 2020 $ (6,739) Pension and other postemployment benefit plans obligations Other comprehensive income before reclassification, net of tax of $587 (1,932) Amounts reclassified from accumulated other comprehensive loss, net of tax of $(298) 894 Other comprehensive loss (1,038) December 31, 2020 (7,777) Pension and other postemployment benefit plans obligations Other comprehensive loss before reclassification, net of tax of $11 78 Amounts reclassified from accumulated other comprehensive loss, net of tax of $(390) 1,172 Other comprehensive income 1,250 December 31, 2021 (6,527) The following table sets forth the effect of reclassifications from accumulated other comprehensive loss on our Consolidated Statements of Income for the periods indicated: Affected Line Item in the Details about Accumulated Other Comprehensive Years Ended December 31, Consolidated Statements of Loss Components 2021 2020 2019 Income ( Thousands of dollars ) Pension and other postemployment benefit plan obligations (a) Amortization of net loss $ 45,896 $ 42,492 $ 35,283 Amortization of unrecognized prior service cost (279) (117) (673) 45,617 42,375 34,610 Regulatory adjustments (b) (44,055) (41,183) (33,758) 1,562 1,192 852 Income before income taxes (390) (298) (213) Income tax expense Total reclassifications for the period $ 1,172 $ 894 $ 639 Net income (a) These components of accumulated other comprehensive loss are included in the computation of net periodic benefit cost. See Note 13 for additional information regarding 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 10 for additional information regarding our regulatory assets and liabilities.

EARNINGS PER SHARE (Notes)

EARNINGS PER SHARE (Notes)	12 Months Ended
	Dec. 31, 2021
EARNINGS PER SHARE OF COMMON STOCK, BASIC AND DILUTED [Line Items]
Earnings Per Share [Text Block]	EARNINGS PER SHARE The following tables set forth the computation of basic and diluted EPS from continuing operations for the periods indicated: Year Ended December 31, 2021 Income Shares Per Share ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 206,434 53,575 $ 3.85 Diluted EPS Calculation Effect of dilutive securities — 99 Net income available for common stock and common stock equivalents $ 206,434 53,674 $ 3.85 Year Ended December 31, 2020 Income Shares Per Share ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 196,412 53,133 $ 3.70 Diluted EPS Calculation Effect of dilutive securities — 237 Net income available for common stock and common stock equivalents $ 196,412 53,370 $ 3.68 Year Ended December 31, 2019 Income Shares Per Share ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 186,749 52,895 $ 3.53 Diluted EPS Calculation Effect of dilutive securities — 345 Net income available for common stock and common stock equivalents $ 186,749 53,240 $ 3.51

DERIVATIVE FINANCIAL INSTRUMENT

DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Notes)	12 Months Ended
	Dec. 31, 2021
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Fair Value Disclosures	DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS Derivative Instruments - At December 31, 2021, we held purchased natural gas call options for the heating season ending March 2022, with total notional amounts of 13.2 Bcf, for which we paid premiums of $9.5 million, and which had a fair value of $2.3 million. At December 31, 2020, we held purchased natural gas call options for the heating season ended March 2021, with total notional amounts of 14.7 Bcf, for which we paid premiums of $6.7 million, and which had a fair value of $0.8 million. 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, accounts receivable and accounts payable is equal to book value, due to the short-term nature of these items. Our cash and cash equivalents are comprised of cash and money market accounts, which we consider to be Level 1. At December 31, 2021, other current and noncurrent assets included $6.9 million of corporate bonds and $3.5 million of United States treasury notes, for which the fair value approximates our cost, and are classified as Level 2 and Level 1, respectively. At December 31, 2020, other current and noncurrent assets included $1.6 million of corporate bonds and $3.2 million of United States treasury notes, for which the fair value approximates our cost, and are classified as Level 2 and Level 1, respectively. Short-term notes payable and commercial paper are due upon demand and, therefore, the carrying amounts approximate fair value and are classified as Level 1. The book value of our long-term debt, including current maturities, was $3.7 billion and $1.6 billion at December 31, 2021 and 2020, respectively. The estimated fair value of our long-term debt, including current maturities, was $3.9 billion and $2.0 billion at December 31, 2021 and 2020, respectively. The estimated fair value of our long-term debt was determined using quoted market prices, and is considered Level 2.

REGULATORY ASSETS AND LIABILITI

REGULATORY ASSETS AND LIABILITIES (Notes)	12 Months Ended
	Dec. 31, 2021
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, net of amortization, and liabilities for the periods indicated: December 31, 2021 Remaining Recovery Period Current Noncurrent Total ( Thousands of dollars ) Winter weather event costs (a) $ 1,536,054 $ 428,023 $ 1,964,077 Under-recovered purchased-gas costs 1 year 31,863 — 31,863 Pension and other postemployment benefit costs See Note 13 11,507 260,559 272,066 Reacquired debt costs 6 years 812 4,070 4,882 MGP remediation costs 15 years 98 29,841 29,939 Ad-valorem tax 1 year 8,561 — 8,561 WNA 1 year 10,044 — 10,044 Customer credit deferrals 1 year 10,685 — 10,685 Other 1 to 18 years 2,052 2,369 4,421 Total regulatory assets, net of amortization 1,611,676 724,862 2,336,538 Income tax rate changes (a) — (552,928) (552,928) Over-recovered purchased-gas costs 1 year (8,090) — (8,090) Total regulatory liabilities (8,090) (552,928) (561,018) Net regulatory assets and liabilities $ 1,603,586 $ 171,934 $ 1,775,520 (a) Recovery period varies by jurisdiction. See discussion below for additional information regarding our regulatory assets related to winter weather event costs and regulatory liabilities related to federal income tax rate changes. December 31, 2020 Remaining Recovery Period Current Noncurrent Total ( Thousands of dollars ) Under-recovered purchased-gas costs 1 year $ 16,502 $ — $ 16,502 Pension and other postemployment benefit costs See Note 13 16,541 341,266 357,807 Reacquired debt costs 7 years 812 4,866 5,678 MGP remediation costs 15 years 98 18,711 18,809 Ad-valorem tax 1 year 5,558 — 5,558 WNA 1 year 4,806 — 4,806 Customer credit deferrals 1 year 10,267 — 10,267 Other 1 to 18 years 2,189 2,113 4,302 Total regulatory assets, net of amortization 56,773 366,956 423,729 Income tax rate changes (a) — (547,563) (547,563) Over-recovered purchased-gas costs 1 year (15,761) — (15,761) Total regulatory liabilities (15,761) (547,563) (563,324) Net regulatory assets and liabilities $ 41,012 $ (180,607) $ (139,595) (a) Recovery period varies by jurisdiction. See discussion below for additional information regarding our regulatory liabilities related to federal income tax rate changes. 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 or base rates, and we believe that we will be able to recover such costs consistent with our historical recoveries. 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 Kansas, Oklahoma, and Texas. During this time, the governors of Kansas, Oklahoma, 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 Kansas, Oklahoma, and Texas jurisdictions, which resulted in aggregated natural gas purchases for the month of February 2021 of approximately $2.1 billion. On February 16, 2021, the OCC approved an emergency order (i) directing natural gas and electric utilities to prioritize deliveries of natural gas and electricity for services necessary for life, health, and public safety, and of natural gas to electric generation facilities that serve human needs customers, and (ii) directing local utilities to communicate with their customers in order to reduce all non-essential energy consumption, and to reduce load in a safe and reasonable manner. The OCC order recognized that the severe weather conditions resulted in increased commodity prices for both gas and electric utilities, along with issues relating to commodity acquisition, line pressure, and supply shortages. The OCC order expired on February 20, 2021. In response to a motion filed by Oklahoma Natural Gas, on March 2, 2021, the OCC issued an order stating that Oklahoma Natural Gas shall defer to a regulatory asset the extraordinary costs associated with this unprecedented winter weather event, including commodity costs, operational costs and carrying costs. The order further states that after all deferred costs have been accumulated and recorded, Oklahoma Natural Gas shall file a compliance report detailing the extent of such costs incurred. The order also provided that recovery of the deferred costs will be addressed in a future proceeding that will include a prudence review. In April 2021, a bill permitting the state to pursue securitized financing of extraordinary expenses, such as fuel costs, financing costs and other operational costs incurred by regulated utilities during extreme weather events, was signed into law by the Oklahoma governor. This bill gives the OCC the authority to approve amounts to be recovered from the issuance of ratepayer-backed securitized bonds by the ODFA. On April 29, 2021, Oklahoma Natural Gas submitted an initial application requesting a financing order pursuant to this legislation. On July 30, 2021, Oklahoma Natural Gas filed a supplemental motion with its compliance report pursuant to the March 2, 2021 order from the OCC detailing the extent of extraordinary costs incurred and all required components pursuant to the legislation for the issuance of a financing order, which includes a proposed period of 20 years over which these costs will be collected from customers. On October 4, 2021, the Public Utility Division of the OCC filed responsive testimony recommending that a financing order for securitization be approved. A joint stipulation and settlement was filed on November 18, 2021, ahead of the hearing before the administrative law judge on November 22, 2021. The joint stipulation and settlement agreement includes an agreement that a financing order should be issued to recover through securitization all extreme gas purchase and extraordinary costs over a 25-year period. At the hearing on November 22, 2021, the administrative law judge recommended approval of the joint stipulation and settlement agreement. On January 25, 2022, the OCC approved a financing order, which reflected the terms of the settlement agreement. Following the issuance of the financing order, there is a 30-day period during which parties to our application may appeal the financing order to the Oklahoma Supreme Court. The securitization legislation allows the ODFA 24 months to complete the process to issue the securitized bonds; however, the financing order requests the ODFA to issue bonds and provide the net proceeds to Oklahoma Natural Gas as soon as feasible, but no later than December 31, 2022. At December 31, 2021, Oklahoma Natural Gas has deferred approximately $1.3 billion in extraordinary costs attributable to Winter Storm Uri. On February 15, 2021, the KCC issued an emergency order (i) directing all jurisdictional natural gas and electric utilities to coordinate efforts and take all reasonably feasible, lawful, and appropriate actions to ensure adequate delivery of natural gas and electricity to interconnected, non-jurisdictional utilities in Kansas, (ii) 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 in Kansas, and (iii) allowing those electric and natural gas distribution utilities who incur extraordinary costs to ensure their customers and other interconnected customers continued to receive utility service during this unprecedented cold weather event to defer those costs and carrying costs to a regulatory asset account. Each jurisdictional utility was required to file a compliance report detailing the extent of such costs incurred and presenting a plan to minimize the financial impacts of this event on ratepayers over a reasonable time frame. These costs were subject to review for reasonableness and accuracy in future regulatory proceedings. In March 2021, the KCC issued an order adopting the KCC staff’s recommendation to open company-specific dockets to accept each utility’s filing of financial impact compliance reports and permit the KCC staff to conduct a review of the utility’s compliance report and its actions during the winter weather event. In April 2021, a bill permitting the utilities to pursue securitization to finance extraordinary expenses incurred during extreme weather events, was signed into law by the Kansas governor. The bill gives the KCC the authority to oversee and authorize the issuance of ratepayer-backed securitized bonds issued by a public utility. 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 October 2021, a nonunanimous settlement agreement was filed with the KCC to reach a resolution on these penalties. Prior to a hearing on the amended settlement in January 2022, all parties reached a unanimous settlement, which was filed with a motion requesting approval of the unanimous settlement. Under the terms of the amended unanimous settlement, if approved, the carrying charge on assessed penalties was reduced to two percent, consistent with the nonunanimous agreement in the financial docket. Any amounts collected from these penalties would reduce the regulatory asset for the winter weather event by no more than $52.4 million. A hearing on the settlement was held on February 4, 2022. The KCC has until March 7, 2022, to issue an order on the motion. In July 2021, Kansas Gas Service submitted its financial plan to the KCC as required by the company-specific docket opened by the KCC in March 2021. The plan includes a proposal to issue securitized bonds to recover the extraordinary costs resulting from Winter Storm Uri from its customers over a period of either 5, 7, or 10 years. In November 2021, a nonunanimous settlement agreement was filed with the KCC that would allow Kansas Gas Service to recover extraordinary costs as of October 31, 2021, net of any penalties recovered from marketers and individually-balanced transportation customers, plus carrying costs calculated at two percent. Subsequently, all parties reached agreement on the settlement’s terms which resulted in the nonunanimous agreement becoming a unanimous settlement agreement. The extraordinary costs, other than purchased gas costs, will be trued-up and validated. The settlement agreement supports Kansas Gas Service seeking a financing order from the KCC for the issuance of securitized utility tariff bonds. The KCC issued an order approving the unanimous settlement agreement on February 8, 2022. Kansas Gas Service expects to file an application, in a separate proceeding, requesting a financing order in the first quarter of 2022. The KCC will have 180 days from the date of the filing to consider Kansas Gas Service’s application. If the KCC approves the financing order, we can begin the process to issue the securitized bonds. At December 31, 2021, Kansas Gas Service has deferred approximately $388.3 million in extraordinary costs associated with Winter Storm Uri and has not collected any penalties from marketers or individually-balanced transportation customers. On February 13, 2021, the RRC issued a Notice to Local Distribution Companies acknowledging that due to the demand for natural gas expected during the upcoming winter weather event, natural gas utility LDCs may be required to pay extraordinarily high prices in the market for natural gas and may be subjected to other extraordinary costs when responding to the event. The RRC also encouraged natural gas utilities to continue to work to ensure that the citizens of the State of Texas were provided with safe and reliable natural gas service. To partially defer and reduce the impact on customers for these costs that ultimately are reflected in customer bills, the RRC authorized LDCs to record a regulatory asset to account for the extraordinary costs associated with this winter weather event, including but not limited to gas cost and other costs related to the procurement and transportation of gas supply. These costs will be subject to review for reasonableness and accuracy in future regulatory proceedings. In June 2021, a bill permitting the state to pursue securitized financing of extraordinary expenses, such as fuel costs, financing costs and other operational costs incurred by utilities during Winter Storm Uri, was signed into law by the Texas governor. This bill gives the RRC the authority to approve amounts to be recovered from the issuance of ratepayer-backed securitized bonds by the TPFA. Pursuant to this legislation and a June 17, 2021 RRC Notice to Gas Utilities, Texas Gas Service submitted an application to the RRC on July 30, 2021, for an order authorizing the amount of extraordinary costs for recovery and other such specifications necessary for the issuance of securitized bonds. In October 2021, Texas Gas Service, the other natural gas utilities in Texas participating in the securitization process, the staff of the RRC and all intervenors filed a unanimous settlement agreement with the RRC. The settlement agreement provides that all costs to purchase natural gas during Winter Storm Uri by Texas Gas Service were reasonable, necessary and prudently incurred. Texas Gas Service agreed to reduce its regulatory asset amount to be securitized by the amount of extraordinary costs attributable to the West Texas service area, which will be recovered through a separate surcharge over a three-year period. The unanimous settlement agreement was approved by the RRC in November 2021. On February 8, 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 Texas Natural Gas Securitization Finance Corporation, a new independent public authority, for purposes of issuing the securitized bonds and has begun the process to issue the securitized bonds. At December 31, 2021, Texas Gas Service has deferred approximately $256.6 million in extraordinary costs associated with Winter Storm Uri, which includes $59.5 million attributable to the West Texas service area. Pursuant to the approved settlement order, Texas Gas Service began collecting the extraordinary costs, including carrying costs, associated with Winter Storm Uri attributable to the West Texas service area from those customers in January 2022. We intend to use the proceeds of these securitized bonds to satisfy our senior notes coming due in March 2023. In accordance with these regulatory orders associated with the winter weather event, we have deferred approximately $2.0 billion in extraordinary costs for natural gas purchases, related financing and carrying costs and other operational costs, which includes $1.3 billion of costs attributable to Oklahoma Natural Gas customers, $388.3 million of costs attributable to Kansas Gas Service customers and $256.6 million of costs attributable to Texas Gas Service customers, including $59.5 million attributable to the West Texas service area that will be recovered over a three year period beginning January 1, 2022. The amounts deferred at December 31, 2021, include invoiced costs for natural gas purchases that have not been paid as we work with our suppliers to resolve discrepancies in invoiced amounts. The amounts deferred may be adjusted as the differences are resolved. In addition, as a result of Winter Storm Uri, we were assessed penalties as a result of over- or under-deliveries of natural gas during periods that operational flow orders were imposed on us. Regarding Kansas Gas Service’s motion requesting a limited waiver of penalty provisions of its tariff, if the nonunanimous settlement agreement filed with the KCC is approved, we anticipate assessing penalties on the marketers and individually-balanced transport customers we serve or their agents. Amounts recorded reflect management’s best estimate of the amounts we may pay or receive and may be adjusted in future periods as the disposition of such penalties is determined. As these amounts are related to the extraordinary gas purchase costs associated with Winter Storm Uri, which are deferred, future adjustments to the amounts we have deferred 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 KCC. 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. Ad-valorem tax represents an increase or decrease in Kansas Gas Service’s taxes above or below the amount approved in base rates. 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. At December 31, 2021, the noncurrent regulatory liability for income tax rate changes includes the reclassification of $29.3 million of deferred taxes related to the reduction of the state income tax rate in Oklahoma. Additionally, it includes the reclassification of $84.2 million of deferred taxes related to the elimination of state income tax for utilities in Kansas at December 31, 2021 and 2020. See Note 14 for additional information regarding the impact of income tax rate changes during the year ended December 31, 2021. See Note 16 for additional information regarding our regulatory assets for MGP remediation costs. We have received accounting orders in each of our jurisdictions authorizing us to accumulate and defer for regulatory purposes certain incremental costs incurred, including bad debt expenses, and certain lost revenues, net of offsetting expense reductions associated with COVID-19. Pursuant to these orders, the recovery of any net incremental costs and lost revenues will be determined in future rate cases or alternative rate recovery filings in each jurisdiction. For financial reporting purposes, any amounts deferred as a regulatory asset for future recovery under these accounting orders must be probable of recovery. At December 31, 2021, no regulatory assets have been recorded. We continue to evaluate the impacts of COVID-19 on our business and will record regulatory assets for financial reporting purposes at such time as recovery is deemed probable.

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Notes)	12 Months Ended
	Dec. 31, 2021
Entity Information
PROPERTY, PLANT AND EQUIPMENT	PROPERTY, PLANT AND EQUIPMENT The following table sets forth our property, plant and equipment by property type, for the periods indicated: December 31, December 31, 2021 2020 ( Thousands of dollars ) Natural gas distribution pipelines and related equipment $ 5,836,066 $ 5,517,488 Natural gas transmission pipelines and related equipment 624,528 586,360 General plant and other 712,659 657,037 Construction work in process 101,015 77,718 Property, plant and equipment 7,274,268 6,838,603 Accumulated depreciation and amortization (2,083,433) (1,971,546) Net property, plant and equipment $ 5,190,835 $ 4,867,057 We compute depreciation expense by applying composite, straight-line rates of approximately 2.5 percent to 3.5 percent that were approved by various regulatory authorities. We recorded capitalized interest of $4.2 million, $4.2 million and $4.6 million for the years ended December 31, 2021, 2020 and 2019, respectively. We incurred liabilities for construction work in process that had not been paid at December 31, 2021, 2020 and 2019 of $25.6 million , $24.3 million and $20.9 million, respectively. Such amounts are not included in capital expenditures or in the change of working capital items on our Consolidated Statements of Cash Flows.

SHARE-BASED PAYMENTS (Notes)

SHARE-BASED PAYMENTS (Notes)	12 Months Ended
	Dec. 31, 2021
Share-based Payments [Line Items]
Disclosure of Compensation Related Costs, Share-based Payments	SHARE-BASED PAYMENTS The ECP provides for the granting of stock-based compensation, including incentive stock options, nonstatutory stock options, stock bonus awards, restricted stock awards, restricted stock unit awards, performance stock awards and performance unit awards to eligible employees and the granting of stock awards to nonemployee directors. At December 31, 2021, we have 4.3 million shares of common stock reserved for issuance under the ECP. At December 31, 2021, we had approximately 1.8 million shares available for issuance under the ECP, which reflect shares issued and estimated shares expected to be issued upon vesting of outstanding awards granted under the plan, less forfeitures. The plan allows for the deferral of awards granted in stock or cash, in accordance with the Code section 409A requirements. Compensation expense for our ECP share-based payment plans was $7.5 million, net of tax benefits of $2.5 million, for 2021, $7.0 million, net of tax benefits of $2.3 million, for 2020, and $6.8 million, net of tax benefits of $2.2 million, for 2019. Restricted Stock Unit Awards - We have granted restricted stock unit awards to key employees that vest over a service period of generally three years and entitle the grantee to receive shares of our common stock. Restricted stock unit awards granted accrue dividend equivalents in the form of additional restricted stock units prior to vesting. Restricted stock unit awards are measured at fair value as if they were vested and issued on the grant date and adjusted for estimated forfeitures. Compensation expense is recognized on a straight-line basis over the vesting period of the award. A forfeiture rate of 3 percent per year based on historical forfeitures under our share-based payment plans is used. Performance Stock Unit Awards - We have granted performance stock unit awards to key employees. The shares of common stock underlying the performance stock units vest at the expiration of a service period of generally three years if certain performance criteria are met by us as determined by the Executive Compensation Committee of the Board of Directors. Upon vesting, a holder of performance stock units is entitled to receive a number of shares of common stock equal to a percentage (0 percent to 200 percent) of the performance stock units granted, based on our total shareholder return over the vesting period, compared with the total shareholder return of a peer group of other utilities over the same period. If paid, the outstanding performance stock unit awards entitle the grantee to receive shares of our common stock. The outstanding performance stock unit awards are equity awards with a market-based condition, which results in the compensation expense for these awards being recognized on a straight-line basis over the requisite service period, provided that the requisite service period is fulfilled, regardless of when, if ever, the market condition is satisfied. The performance stock unit awards granted accrue dividend equivalents in the form of additional performance stock units prior to vesting. The fair value of these performance stock units was estimated on the grant date based on a Monte Carlo model. The compensation expense on these awards will only be adjusted for forfeitures. A forfeiture rate of 3 percent per year based on historical forfeitures under our share-based payment plans is used. Restricted Stock Unit Award Activity As of December 31, 2021, there was $3.6 million of total unrecognized compensation expense related to the nonvested restricted stock unit awards, which is expected to be recognized over a weighted-average period of 1.7 years. The following tables set forth activity and various statistics for restricted stock unit awards outstanding under the respective plans for the period indicated: Number of Weighted- Nonvested at December 31, 2020 99,800 $ 82.29 Granted 50,353 $ 72.69 Vested (42,821) $ 71.67 Forfeited (13,058) $ 81.07 Nonvested at December 31, 2021 94,274 $ 82.16 2021 2020 2019 Weighted-average grant date fair value (per share) $ 72.69 $ 96.21 $ 83.94 Fair value of shares granted (thousands of dollars) $ 3,660 $ 3,005 $ 3,001 For the years ended December 31, 2021, 2020 and 2019, the fair value of restricted stock vested was $3.4 million, $3.3 million, and $3.3 million, respectively. Performance Stock Unit Award Activity As of December 31, 2021, there was $6.6 million of total unrecognized compensation expense related to the nonvested performance stock unit awards, which is expected to be recognized over a weighted-average period of 1.7 years. The following tables set forth activity and various statistics related to our performance stock unit awards and the assumptions used by us in the valuations of the 2021, 2020 and 2019 grants at the grant date: Number of Weighted- Nonvested at December 31, 2020 208,520 $ 87.97 Granted 107,381 $ 82.51 Vested (76,483) $ 74.04 Forfeited (40,819) $ 89.19 Nonvested at December 31, 2021 198,599 $ 90.13 2021 2020 2019 Volatility (a) 32.70% 16.40% 18.70% Dividend yield 3.19% 2.25% 2.38% Risk-free interest rate (b) 0.20% 1.40% 2.50% (a) - Volatility based on historical volatility over three years using daily stock price observations of our peer utilities. (b) - Using 3-year treasury. 2021 2020 2019 Weighted-average grant date fair value (per share) $ 82.51 $ 102.77 $ 89.86 Fair value of shares granted (thousands of dollars) $ 8,860 $ 6,502 $ 6,401 For the years ended December 31, 2021, 2020 and 2019, the fair value of performance stock vested was $7.2 million, $10.2 million, and $12.7 million, respectively. Employee Stock Purchase Plan We have reserved a total of 1.25 million shares of common stock for issuance under our ESPP. Employees can choose to have up to 10 percent of their annual base pay withheld to purchase our common stock, subject to terms and limitations of the plan. The purchase price of the stock is 85 percent of the lower of the average market price of our common stock on the grant date or exercise date. Approximately 44 percent, 50 percent and 44 percent of employees participated in the plan in 2021, 2020 and 2019, respectively. For the years ended December 31, 2021, 2020 and 2019, employees purchased 89,240, 92,507, and 71,613 shares, respectively, at an average price of $63.41, $64.77 and $71.42, respectively. Compensation expense, before taxes, was $1.1 million, $1.1 million and $1.5 million in 2021, 2020 and 2019, respectively.

EMPLOYEE BENEFIT PLANS (Notes)

EMPLOYEE BENEFIT PLANS (Notes)	12 Months Ended
	Dec. 31, 2021
EMPLOYEE BENEFIT PLANS [Abstract]
Pension and Other Postemployment Benefits Disclosure [Text Block]	EMPLOYEE BENEFIT PLANS Defined Benefit Pension and Other Postemployment Benefit Plans Defined Benefit Pension Plans - We have a defined benefit pension plan and a supplemental executive retirement plan, both of which are closed to new participants. Certain employees of the Texas Gas Service division are entitled to benefits under a frozen cash-balance pension plan. We fund our defined benefit pension costs at a level needed to maintain or exceed the minimum funding levels required by the Employee Retirement Income Security Act of 1974, as amended, and the Pension Protection Act of 2006. Other Postemployment Benefit Plans - We sponsor health and welfare plans that provide postemployment medical and life insurance benefits to certain employees who retire with at least five years of service. The postemployment medical plan is contributory based on hire date, age and years of service, with retiree contributions adjusted periodically, and contains other cost-sharing features such as deductibles and coinsurance. Actuarial Assumptions - The following table sets forth the weighted-average assumptions used to determine benefit obligations for pension and postemployment benefits for the periods indicated: December 31, 2021 2020 Discount rate - pension plans 3.05% 2.80% Discount rate - other postemployment plans 3.00% 2.70% Compensation increase rate 3.10% - 5.00% 3.10% - 3.90% The following table sets forth the weighted-average assumptions used by us to determine the periodic benefit costs for the periods indicated: Years Ended December 31, 2021 2020 2019 Discount rate - pension plans 2.80% 3.50% 4.40% Discount rate - other postemployment plans 2.70% 3.40% 4.40% Expected long-term return on plan assets - pension plans 7.15% 7.20% 7.20% Expected long-term return on plan assets - other postemployment plans 7.50% 7.65% 7.35% Compensation increase rate 3.10% - 3.90% 3.10% - 4.00% 3.20% - 4.00% We determine our discount rates annually. We estimate our discount rate based upon a comparison of the expected cash flows associated with our future payments under our defined benefit pension and other postemployment obligations to a hypothetical bond portfolio created using high-quality bonds that closely match expected cash flows. Bond portfolios are developed by selecting a bond for each of the next 60 years based on the maturity dates of the bonds. Bonds selected to be included in the portfolios are only those rated by Moody’s as AA- or better and exclude callable bonds, bonds with less than a minimum issue size, yield outliers and other filtering criteria to remove unsuitable bonds. We determine our overall expected long-term rate of return on plan assets, based on our review of historical returns and economic growth models. We update our assumed mortality rates to incorporate new tables issued by the Society of Actuaries as needed. Regulatory Treatment - 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 current funding requirements and 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 capitalize all eligible service cost and non-service cost components pursuant to the accounting requirements of ASC Topic 980 (Regulated Operations) for rate-regulated entities, as these costs are authorized by our regulators to be included in capitalized costs. Our consolidated balance sheets reflect the capitalized non-service cost components as a regulatory asset. We have recognized a regulatory asset of $6.1 million and $6.0 million as of December 31, 2021 and December 31, 2020, respectively. See Note 10 for additional information. Obligations and Funded Status - The following table sets forth our defined benefit pension and other postemployment benefit plans, benefit obligations and fair value of plan assets for the periods indicated: Pension Benefits Other Postemployment Benefits December 31, December 31, 2021 2020 2021 2020 Changes in Benefit Obligation (Thousands of dollars) Benefit obligation, beginning of period $ 1,077,641 $ 1,001,368 $ 239,530 $ 230,490 Service cost 13,811 12,869 1,587 1,692 Interest cost 29,458 34,179 6,251 7,557 Plan participants’ contributions — — 3,226 3,500 Actuarial loss (gain) (19,587) 91,566 (8,894) 14,013 Benefits paid (51,333) (62,341) (18,894) (17,722) Benefit obligation, end of period 1,049,990 1,077,641 222,806 239,530 Change in Plan Assets Fair value of plan assets, beginning of period 987,583 907,974 230,895 207,182 Actual return (loss) on plan assets 75,999 140,939 14,786 35,837 Employer contributions 995 1,011 1,981 2,098 Plan participants’ contributions — — 3,226 3,500 Benefits paid (51,333) (62,341) (18,894) (17,722) Settlements — — — — Fair value of assets, end of period 1,013,244 987,583 231,994 230,895 Benefit Asset (Obligation), net at December 31 $ (36,746) $ (90,058) $ 9,188 $ (8,635) Other noncurrent assets — — 9,188 — Current liabilities (1,521) (1,056) — — Noncurrent liabilities (35,225) (89,002) — (8,635) Benefit Asset (Obligation), net at December 31 $ (36,746) $ (90,058) $ 9,188 $ (8,635) The accumulated benefit obligation for our defined benefit pension plans was $1.0 billion and $1.0 billion at December 31, 2021 and 2020, respectively. At December 31, 2021 and 2020, the accumulated benefit obligations of each of our plans exceeded the fair value of the related plan’s assets. For the year ended December 31, 2021, the pension benefit obligations experienced an actuarial gain of $19.6 million primarily due to the impact of increases in the discount rates used to calculate the benefit obligations. For the year ended December 31, 2020, the pension benefit obligations experienced an actuarial loss of $91.6 million primarily due to the impact of decreases in the discount rates used to calculate the benefit obligations. Benefits paid for 2020 reflects $12.5 million of lump sum payments to certain terminated-vested participants. In 2022, our contributions are expected to be $1.5 million to our defined benefit pension plans, and no contributions are expected to be made to our other postemployment benefit plans. Components of Net Periodic Benefit Cost - The following tables set forth the components of net periodic benefit cost, prior to regulatory deferrals, for our defined benefit pension and other postemployment benefit plans for the period indicated: Pension Benefits Year Ended December 31, 2021 2020 2019 (Thousands of dollars) Components of net periodic benefit cost Service cost $ 13,811 $ 12,869 $ 12,030 Interest cost (a) 29,458 34,179 40,670 Expected return on assets (a) (62,382) (61,119) (61,939) Amortization of net loss (a) 45,523 42,319 33,039 Net periodic benefit cost $ 26,410 $ 28,248 $ 23,800 (a) These amounts, net of any amounts capitalized as a regulatory asset since adoption of ASU 2017-07 on January 1, 2018, have been recognized as other income (expense), net in the Consolidated Statements of Income. See Note 15 for additional detail of our other income (expense), net. Other Postemployment Benefits Year Ended December 31, 2021 2020 2019 (Thousands of dollars) Components of net periodic benefit cost Service cost $ 1,587 $ 1,692 $ 1,734 Interest cost (a) 6,251 7,557 9,318 Expected return on assets (a) (16,807) (15,469) (12,586) Amortization of unrecognized prior service cost (a) (279) (117) (673) Amortization of net loss (a) 373 173 2,244 Net periodic benefit cost (credit) $ (8,875) $ (6,164) $ 37 (a) These amounts, net of any amounts capitalized as a regulatory asset since adoption of ASU 2017-07 on January 1, 2018, have been recognized as other income (expense), net in the Consolidated Statements of Income. See Note 15 for additional detail of our other income (expense), net. Other Comprehensive Income (Loss) - The following table sets forth the amounts recognized in other comprehensive income (loss), net of regulatory deferrals, related to our defined benefit pension benefits for the period indicated: Pension Benefits Year Ended December 31, 2021 2020 2019 (Thousands of dollars) Net gain (loss) arising during the period $ 67 $ (2,519) $ (2,766) Amortization of loss 1,562 1,192 852 Deferred income taxes (379) 289 479 Total recognized in other comprehensive income (loss) $ 1,250 $ (1,038) $ (1,435) Due to our regulatory deferrals, there were no amounts recognized in other comprehensive income (loss) related to our other postemployment benefits for the periods presented. The tables below set forth the amounts in accumulated other comprehensive loss that had not yet been recognized as components of net periodic benefit expense for the periods indicated: Pension Benefits December 31, 2021 2020 (Thousands of dollars) Accumulated loss $ (272,332) $ (351,059) Accumulated other comprehensive loss (272,332) (351,059) Regulatory asset for regulated entities 264,027 341,125 Accumulated other comprehensive loss (8,305) (9,934) Deferred income taxes 1,778 2,157 Accumulated other comprehensive loss, $ (6,527) $ (7,777) Other Postemployment Benefits December 31, 2021 2020 (Thousands of dollars) Prior service credit $ (194) $ 85 Accumulated loss (5,887) (13,134) Accumulated other comprehensive loss $ (6,081) $ (13,049) Regulatory asset for regulated entities 6,081 13,049 Accumulated other comprehensive loss $ — $ — Health Care Cost Trend Rates - The following table sets forth the assumed health care cost-trend rates for the periods indicated: 2021 2020 Health care cost-trend rate assumed for next year 6.00% 6.25% Rate to which the cost-trend rate is assumed to decline 4.50% 4.50% Year that the rate reaches the ultimate trend rate 2028 2026 Plan Assets - Our investment strategy is to invest plan assets in accordance with sound investment practices that emphasize long-term fundamentals. The goal of this strategy is to maximize investment returns while managing risk in order to meet the plan’s current and projected financial obligations. To achieve this strategy, we have established a liability-driven investment strategy to change the allocations as the funded status of the defined benefit pension plan increases. The plan’s investments include a diverse blend of various domestic and international equities, investment-grade debt securities which mirror the cash flows of our liability, insurance contracts and alternative investments. The current target allocation for the assets of our defined benefit pension plan is as follows: Investment-grade bonds 60.0 % U.S. large-cap equities 14.0 % Alternative investments 10.0 % Developed foreign large-cap equities 7.0 % Mid-cap equities 5.0 % Emerging markets equities 1.0 % Small-cap equities 3.0 % Total 100 % As part of our risk management for the plans, minimums and maximums have been set for each of the asset classes listed above. All investment managers for the plan are subject to certain restrictions on the securities they purchase and, with the exception of indexing purposes, are prohibited from owning our stock. The current target allocation for the assets of our other postemployment benefits plan is 65 percent fixed income securities and 35 percent equity securities. The following tables set forth our pension benefits and other postemployment benefits plan assets by fair value category as of the measurement date: Pension Benefits December 31, 2021 Asset Category Level 1 Level 2 Level 3 Total (Thousands of dollars) Investments: Equity securities (a) $ 223,871 $ — $ — $ 223,871 Government obligations — 205,741 — 205,741 Corporate obligations (b) — 440,445 — 440,445 Cash and money market funds (c) 3,864 30,546 — 34,410 Insurance contracts and group annuity contracts — — 17,301 17,301 Other investments (d) — 20 91,456 91,476 Total assets $ 227,735 $ 676,752 $ 108,757 $ 1,013,244 (a) - This category represents securities of the various market sectors from diverse industries. (b) - This category represents bonds from diverse industries. (c) - This category primarily represents money market funds. (d) - This category represents alternative investments such as hedge funds and other financial instruments. Pension Benefits December 31, 2020 Asset Category Level 1 Level 2 Level 3 Total (Thousands of dollars) Investments: Equity securities (a) $ 392,639 $ 35,454 $ — $ 428,093 Government obligations — 78,080 — 78,080 Corporate obligations (b) — 343,118 — 343,118 Cash and money market funds (c) 1,589 23,311 — 24,900 Insurance contracts and group annuity contracts — — 24,603 24,603 Other investments (d) — 1,155 87,634 88,789 Total assets $ 394,228 $ 481,118 $ 112,237 $ 987,583 (a) - This category represents securities of the various market sectors from diverse industries. (b) - This category represents bonds from diverse industries. (c) - This category primarily represents money market funds. (d) - This category represents alternative investments such as hedge funds and other financial instruments. Other Postemployment Benefits December 31, 2021 Asset Category Level 1 Level 2 Level 3 Total (Thousands of dollars) Investments: Equity securities (a) $ 25,577 $ — $ — $ 25,577 Government obligations — 41,366 — 41,366 Corporate obligations (b) — 41,601 — 41,601 Cash and money market funds (c) 542 12,990 — 13,532 Insurance contracts and group annuity contracts (d) — 109,918 — 109,918 Total assets $ 26,119 $ 205,875 $ — $ 231,994 (a) - This category represents securities of the various market sectors from diverse industries. (b) - This category represents bonds from diverse industries. (c) - This category primarily represents money market funds. (d) - This category includes equity securities and bonds held in a captive insurance product. Other Postemployment Benefits December 31, 2020 Asset Category Level 1 Level 2 Level 3 Total (Thousands of dollars) Investments: Equity securities (a) $ 73,578 $ — $ — $ 73,578 Government obligations — — — — Corporate obligations (b) — 39,115 — 39,115 Cash and money market funds (c) 52 8,071 — 8,123 Insurance contracts and group annuity contracts (d) — 110,079 — 110,079 Total assets $ 73,630 $ 157,265 $ — $ 230,895 (a) - This category represents securities of the various market sectors from diverse industries. (b) - This category represents bonds from diverse industries. (c) - This category primarily represents money market funds. (d) - This category includes equity securities and bonds held in a captive insurance product. Insurance contracts and group annuity contracts include investments in the Immediate Participation Guarantee Fund (“IPG Fund”) with John Hancock and are valued at fair value. John Hancock invests the IPG Fund in its general fund portfolio. The contract value of the IPG Fund at the end of the year, which approximates fair value, is estimated. The difference between this estimated balance and the actual balance, as subsequently determined by John Hancock, is charged or credited to the net assets of the plans. Certain investments that are categorized as money market funds in Level 2 and “Other investments” in Level 3 represent alternative investments such as hedge funds and other financial instruments measured using the net asset value per share (or its equivalent) practical expedient. The following tables set forth additional information regarding commitments and redemption limitations of these other investments at the periods indicated: December 31, 2021 Fair Value Unfunded Commitments Redemption Frequency Redemption Notice Period (in thousands) (in days) Grosvenor Registered Multi Limited Partnership $ 44,818 $ — quarterly 65 K2 Institutional Investors II Limited Partnership $ 46,638 $ — quarterly 91 December 31, 2020 Fair Value Unfunded Commitments Redemption Frequency Redemption Notice Period (in thousands) (in days) Grosvenor Registered Multi Limited Partnership $ 42,632 $ — quarterly 65 K2 Institutional Investors II Limited Partnership $ 45,002 $ — quarterly 91 The following table sets forth the reconciliation of Level 3 fair value measurements of our pension plans for the periods indicated: Pension Benefits Insurance Other Total (Thousands of dollars) January 1, 2020 $ 25,988 $ 81,793 $ 107,781 Unrealized gains 1,764 4,849 6,613 Purchases — 992 992 Settlements (3,149) — (3,149) December 31, 2020 $ 24,603 $ 87,634 $ 112,237 Unrealized gains — 1,625 1,625 Unrealized losses (3,368) — (3,368) Purchases — 2,197 2,197 Settlements (3,934) — (3,934) December 31, 2021 $ 17,301 $ 91,456 $ 108,757 Pension and Other Postemployment Benefit Payments - Benefit payments for our defined benefit pension and other postemployment benefit plans for the year ended December 31, 2021 were $51.3 million and $18.9 million, respectively. The following table sets forth the pension benefits and other postemployment benefits payments expected to be paid in 2022-2031: Pension Other Postemployment Benefits to be paid in: (Thousands of dollars) 2022 $ 52,936 $ 15,744 2023 $ 53,745 $ 15,571 2024 $ 54,440 $ 15,184 2025 $ 55,075 $ 14,940 2026 $ 55,852 $ 14,580 2027 through 2031 $ 283,344 $ 67,566 The expected benefits to be paid are based on the same assumptions used to measure our benefit obligation at December 31, 2021, and include estimated future employee service. Other Employee Benefit Plans 401(k) Plan - We have a 401(k) plan which covers all full-time employees, and employee contributions are discretionary. We match 100 percent of each participant’s eligible contribution up to 6 percent of eligible compensation, subject to certain limits. Our contributions to the plan were $14.3 million, $13.8 million and $12.8 million in 2021, 2020 and 2019, respectively. Profit-Sharing Plan - We have a profit-sharing plan for all employees who do not participate in our defined benefit pension plan. We plan to make a contribution to the profit-sharing plan each quarter equal to 1 percent of each participant’s eligible compensation during the quarter. Additional discretionary employer contributions may be made at the end of each year.

INCOME TAXES (Notes)

INCOME TAXES (Notes)	12 Months Ended
	Dec. 31, 2021
Income tax [Line Items]
INCOME TAXES	INCOME TAXES The following table sets forth our provision for income taxes for the periods indicated: Years Ended December 31, 2021 2020 2019 ( Thousands of dollars ) Current income tax provision (benefit) Federal $ (1,568) $ 20,129 $ 24,537 State (1,565) 2,965 5,008 Total current income tax provision (benefit) (3,133) 23,094 29,545 Deferred income tax provision Federal 37,810 10,757 8,375 State 5,639 7,728 4,932 Total deferred income tax provision 43,449 18,485 13,307 Total provision for income taxes $ 40,316 $ 41,579 $ 42,852 The following table is a reconciliation of our income tax provision for the periods indicated: Years Ended December 31, 2021 2020 2019 ( Thousands of dollars ) Income before income taxes $ 246,750 $ 237,991 $ 229,601 Federal statutory income tax rate 21 % 21 % 21 % Provision for federal income taxes 51,817 49,978 48,215 State income taxes, net of federal tax benefit 4,074 10,693 9,758 Amortization of EDIT regulatory liability (17,289) (17,031) (12,828) Tax benefit of employee share-based compensation (469) (1,489) (2,116) Other, net 2,183 (572) (177) Total provision for income taxes $ 40,316 $ 41,579 $ 42,852 As of December 31, 2021, 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. As a regulated entity, the change in ADIT resulting from a change in tax laws or tax rates is recorded as a regulatory liability and is subject to refund to our customers. In May 2021, a bill amending the Oklahoma state income tax code was signed into law that reduced the state income tax rate to four percent from six percent beginning January 1, 2022. As a result of the enactment of this legislation, we remeasured our ADIT. As a regulated entity, the reduction in ADIT of $29.3 million was recorded as a regulatory liability. The impact of the change in the state income tax rate on Oklahoma Natural Gas’ rates, as well as the timing and amount of the impact on the annual crediting mechanism for the EDIT regulatory liability, will be addressed during the processing of the March 15, 2022 PBRC filing. In May 2020, a bill amending the Kansas state income tax code was signed into law that exempts public utilities regulated by the KCC from paying Kansas state income taxes beginning January 1, 2021. As a result of the enactment of this legislation, we remeasured our ADIT. As a regulated entity, the reduction in ADIT of $84.2 million was recorded as an EDIT regulatory liability and will be refunded to our customers. This adjustment had no material impact on our income tax expense and no impact on our cash flows for the years ended December 31, 2021 and 2020. The bill stipulates that, if requested by the utility, this EDIT will be returned to Kansas customers over a period of no less than 30 years, with the exact timing to be determined in our next general rate proceeding. In August 2020, Kansas Gas Service submitted an application to the KCC to reduce its base rates to reflect the elimination of Kansas state income taxes by approximately $4.9 million. In December 2020, the KCC approved the reduction, effective January 1, 2021. The following table sets forth the tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and liabilities for the periods indicated: December 31, 2021 2020 ( Thousands of dollars ) Deferred tax assets Employee benefits and other accrued liabilities $ 11,126 $ 28,127 Regulatory adjustments for enacted tax rate changes 120,051 121,738 Net operating loss 424,861 — Lease obligation basis 6,906 9,319 Other 12,597 4,790 Total deferred tax assets 575,541 163,974 Deferred tax liabilities Excess of tax over book depreciation 734,051 717,492 Winter weather event costs 421,070 — Purchased-gas cost adjustment - other 37,433 5,240 Other regulatory assets and liabilities, net 71,541 88,260 Right-of-use asset basis 6,730 9,788 Total deferred tax liabilities 1,270,825 820,780 Net deferred tax liabilities $ 695,284 $ 656,806 We deduct our purchased gas costs for federal income tax purposes in the period they are paid. As a result of the impacts from Winter Storm Uri, we recorded a $421.1 million (tax effected) increase in our deferred tax liability and an increase in our net operating loss carryforward as of December 31, 2021. At December 31, 2021, we had $386.0 million (tax effected) of federal net operating loss carryforwards and $38.9 million (tax effected) of state net operating loss carryforwards available to offset future taxable income. We have filed our consolidated federal and state income tax returns for years 2018, 2019 and 2020. We are no longer subject to income tax examination for years prior to 2018.

OTHER INCOME AND EXPENSE (Notes

OTHER INCOME AND EXPENSE (Notes)	12 Months Ended
	Dec. 31, 2021
Other Income and Expenses [Abstract]
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: Years Ended December 31, 2021 2020 2019 ( Thousands of dollars ) Net periodic benefit cost other than service cost $ (3,930) $ (5,071) $ (5,895) Earnings on investments associated with nonqualified employee benefit plans 3,699 4,616 5,268 Other, net (2,976) (2,565) (2,349) Total other expense, net $ (3,207) $ (3,020) $ (2,976)

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Notes)	12 Months Ended
	Dec. 31, 2021
Commitments and Contingencies [Line Items]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Commitments - See Note 5 of the Notes to Consolidated Financial Statements in this Annual Report for discussion of operating leases. COVID-19 - Throughout the COVID-19 pandemic, we have continued to provide essential services to our customers. We have implemented a comprehensive set of policies, procedures and guidelines to protect the safety of our employees, customers and communities. Safety protocols developed during the pandemic include remote work for our office-based employees, limiting direct contact with our customers and requiring the use of PPE and a self-assessment health screening mobile application. Impacts on our results of operations as a result of COVID-19 include but are not limited to: • lower late payment, reconnect and collection fees and incremental expenses for bad debts related to the suspension of disconnects for nonpayment until the second quarter of 2021; • incremental expenses for PPE, cleaning supplies, outside services and other expenses; and • lower expenses for travel and employee training that have been impacted by the pandemic. We have received accounting orders in each of our jurisdictions authorizing us to accumulate and defer for regulatory purposes certain incremental costs incurred, including bad debt expenses, and certain lost revenues, net of offsetting expense reductions associated with COVID-19. Recovery of any net incremental costs and lost revenue deferred pursuant to these orders will be determined in future rate cases or alternative rate recovery filings in each jurisdiction. At December 31, 2021, we have not requested recovery of any deferrals pursuant to these orders and no regulatory assets have been recorded. We continue to evaluate the impacts of COVID-19 on our business and will record regulatory assets for financial reporting purposes at such time as recovery is deemed probable. 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 2021, 2020, or 2019. 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 December 31, 2021 and 2020, we have deferred $29.9 million and $18.8 million, respectively, 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 and anticipates that filing will occur in 2022. 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. A remediation plan was submitted to the KDHE concerning this site in 2020 and the KDHE has provided comments that we are addressing. We are also working on a remediation plan that we expect to submit to the KDHE in 2022 for an additional site. During the year ended December 31, 2021, we increased the estimates for contractor costs due to increased demand for the types of resources needed to conduct work contemplated in our remediation plans, resulting in an increase in our reserves of $11.2 million. At December 31, 2021 and 2020, the reserve for remediation of our MGP sites was $22.8 million and $14.5 million, respectively. We also own or retain legal responsibility for certain environmental conditions at a former MGP site in Texas. At the request of the Texas Commission on Environmental Quality, 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. Until the investigation is complete, we are unable to determine what, if any, active remediation will be required. A reliable estimate of potential remediation costs is not feasible at this point due to the amount of uncertainty as to the levels and extent of contamination. 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 years ended December 31, 2021, 2020 and 2019. Environmental issues may exist with respect to MGP sites that are unknown to us. Accordingly, future costs are dependent on the final determination and regulatory approval of any remedial actions, the complexity of the site, level of remediation required, changing technology and governmental regulations, and to the extent not recovered by insurance or recoverable in rates from our customers, could be material to our financial condition, results of operations or cash flows. We are subject to environmental regulation by federal, state and local authorities. Due to the inherent uncertainties surrounding the development of federal and state environmental laws and regulations, we cannot determine with specificity the impact such laws and regulations may have on our existing and future facilities. With the trend toward stricter standards, greater regulation and more extensive permit requirements for the types of assets operated by us, our environmental expenditures could increase in the future, and such expenditures may not be fully recovered by insurance or recoverable in rates from our customers, and those costs may adversely affect our financial condition, results of operations and cash flows. 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 regulating pipeline safety, PHMSA promulgates various regulations. For example, in April 2016, PHMSA published a NPRM, the Safety of Gas Transmission & Gathering Lines Rule, in the Federal Register to revise pipeline safety regulations applicable to the safety of onshore natural gas transmission and gathering pipelines. Proposals included changes to pipeline integrity management requirements and other safety-related requirements. Subsequently, PHMSA announced they would split this NPRM into three separate final rulemakings: • the first final rule addresses the legislative mandates from the Pipeline Safety, Regulatory Certainty and Job Creation Act and is called the Safety of Gas Transmission Pipelines: MAOP Reconfirmation, Expansion of Assessment Requirements, and Other Related Amendments; • the second final rule will be called the Safety of Gas Transmission Pipelines: Repair Criteria, Integrity Management Improvements, Cathodic Protection, Management of Change, and Other Related Amendments and will cover all remaining elements of the NPRM (except for gas gathering pipelines); and • the third final rule will be called the Safety of Gas Gathering Pipelines and will address gas gathering pipelines. On October 1, 2019, PHMSA published the first of the three final rules referenced above, which addressed the 2011 congressional mandates. This final rule expands integrity management principles beyond HCAs and requires operators to collect traceable, verifiable and complete records moving forward, retain existing and new records for the life of the pipeline, and reconfirm pipeline MAOP in populated areas. The final rule also outlines methods for reconfirming a pipeline’s MAOP within 15 years. The first final rule became effective July 1, 2020. Our estimated capital and operating expenditures associated with compliance with the first final rulemaking were not material. PHMSA has not yet issued the second final rule. The potential capital and operating expenditures associated with compliance with this rule are currently being evaluated and could be significant depending on the final regulation. We do not expect to be impacted by the third final rule, as we do not own gas gathering pipelines. Separately, as part of the Consolidated Appropriations Act, 2021, the PIPES Act of 2020 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 final outcome of such matters will not have a material adverse effect on our results of operations, financial position or cash flows.

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2021
Significant Accounting Policies [Line Items]
Basis of Accounting	Basis of Presentation - The consolidated financial statements include the accounts of our natural gas distribution business as set forth in “Organization and Nature of Operations” above. All significant balances and transactions between our subsidiaries have been eliminated.
Use of Estimates	Use of Estimates - The preparation of our consolidated financial statements and related disclosures in accordance with GAAP requires us to make estimates and assumptions with respect to values or conditions that cannot be known with certainty that affect the reported amount of assets and liabilities, and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements. These estimates and assumptions also affect the reported amounts of revenue and expenses during the reporting period. Items that may be estimated include, but are not limited to, the economic useful life of assets, fair value of assets and liabilities, provisions for doubtful accounts receivable, unbilled revenues for natural gas delivered but for which meters have not been read, natural gas purchased but for which no invoice has been received, provision for income taxes, including any deferred income tax valuation allowances, the results of litigation and various other recorded or disclosed amounts. We evaluate these estimates on an ongoing basis using historical experience and other methods we consider reasonable based on the particular circumstances. Nevertheless, actual results may differ significantly from the estimates. Any effects on our financial position or results of operations from revisions to these estimates are recorded in the period when the facts that give rise to the revision become known.
Revenue	Revenues - We recognize revenue from contracts with customers to depict the transfers of goods and services to customers at an amount that we expect to be entitled to receive in exchange for these goods and services. Our sources of revenue are disaggregated by natural gas sales, transportation revenues, and miscellaneous revenues, which are primarily one-time service fees, that meet the requirements of ASC 606. Certain revenues that do not meet the requirements of ASC 606 are classified as other revenues in our Notes to Consolidated Financial Statements in this Annual Report. Our natural gas sales to customers and transportation revenues represent revenues from contracts with customers through implied contracts established by our tariffs approved by the regulatory authorities. Our customers receive the benefits of our performance when the commodity is delivered to the customer. The performance obligation is satisfied over time as the customer receives the natural gas. For deliveries of natural gas, we read meters and bill customers on a monthly cycle. We recognize revenues upon the delivery of natural gas commodity or services rendered to customers. The billing cycles for customers do not necessarily coincide with the accounting periods used for financial reporting purposes. We accrue unbilled revenues for natural gas that has been delivered but not yet billed at the end of an accounting period. We use the invoice method practical expedient, where we recognize revenue for volumes delivered for which we have a right to invoice. Our estimate of accrued unbilled revenue is based on a percentage estimate of amounts unbilled each month, which is dependent upon a number of factors, some of which require management’s judgment. These factors include customer consumption patterns and the impact of weather on usage. The accrued unbilled natural gas sales revenue at December 31, 2021 and 2020 was $183.2 million and $144.9 million, respectively, and is included in accounts receivable on our consolidated balance sheets. Our miscellaneous revenues from contracts with customers represent implied contracts established by our tariff rates approved by the regulatory authorities and include miscellaneous utility services with the performance obligation satisfied at a point in time when services are rendered to the customer. Total other revenues consist of revenues associated with regulatory mechanisms that do not meet the requirements of ASC 606 as revenue from contracts with customers, but authorize us to accrue revenues earned based on tariffs approved by the regulatory authorities. Other revenues - natural gas sales primarily relate to the WNA mechanism in Kansas. This mechanism adjusts our revenues earned for the variance between actual and normal HDDs. This mechanism can have either positive (warmer than normal) or negative (colder than normal) effects on revenues. We collect and remit other taxes on behalf of governmental authorities, and we record these amounts in accrued taxes other than income in our consolidated balance sheets. See Note 2 for additional discussion of revenues.
Cost of Natural Gas [Policy Text Block]	Cost of Natural Gas - Cost of natural gas includes commodity purchases, fuel, storage, transportation and other gas purchase costs recovered through our cost of natural gas regulatory mechanisms and does not include an allocation of general operating costs or depreciation and amortization. These cost of natural gas regulatory mechanisms provide a method of recovering natural gas costs on an ongoing basis without a profit. See Note 10 for additional discussion of purchased gas cost recoveries.
Cash and Cash Equivalents	Cash and Cash Equivalents - Cash equivalents consist of highly liquid investments, which are readily convertible into cash and have original maturities of three months or less.
Accounts Receivable	Accounts Receivable - Accounts receivable represent valid claims against nonaffiliated customers for natural gas sold or services rendered, net of an allowance 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 2.2 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 credit environment and other information. We are able to recover natural gas costs related to uncollectible accounts through purchased-gas cost adjustment mechanisms. At December 31, 2021 and 2020, our allowance for doubtful accounts was $18.7 million and $16.6 million, respectively.
Inventories	Inventories - Natural gas in storage is accounted for on the basis of weighted-average cost. Natural gas inventories that are injected into storage are recorded in inventory based on actual purchase costs, including storage and transportation costs. Natural gas inventories that are withdrawn from storage are accounted for in our purchased-gas cost adjustment mechanisms at the weighted-average inventory cost. Materials and supplies inventories are stated at the lower of weighted-average cost or net realizable value.
Lessee, Leases [Policy Text Block]	Leases - We determine if an arrangement is a lease at inception if the contract conveys the right to control the use and obtain substantially all the economic benefits from the use of an identified asset for a period of time in exchange for consideration. We identify a lease as a finance lease if the agreement includes any of the following criteria: transfer of ownership by the end of the lease term; an option to purchase the underlying asset that the lessee is reasonably certain to exercise; a lease term that represents 75 percent or more of the remaining economic life of the underlying asset; a present value of lease payments and any residual value guaranteed by the lessee that equals or exceeds 90 percent of the fair value of the underlying asset; or an underlying asset that is so specialized in nature that there is no expected alternative use to the lessor at the end of the lease term. A lease that does not meet any of these criteria is considered an operating lease. Lease right-of-use assets represent our right to use an underlying asset for the lease term and lease liabilities represent our obligation to make lease payments arising from the lease. Right-of-use assets and liabilities are recognized at the commencement date of a lease based on the present value of lease payments over the lease term. Our lease terms may include options to extend or terminate the lease. We include these extension or termination options in the determination of the lease term when it is reasonably certain that we will exercise that option. We have lease agreements with lease and non-lease components, which are accounted for separately. Additionally, for certain office equipment leases, we apply a portfolio approach to effectively account for the operating lease right-of-use assets and liabilities. We do not recognize leases having a term of less than one year in our consolidated balance sheets. For purposes of determining the present value of the lease payments, we use a lease’s implicit interest rate when readily determinable. As most of our leases do not provide an implicit interest rate, we use an incremental borrowing rate based on available information at the commencement of the lease. Lease cost for operating leases is recognized on a straight-line basis over the lease term. See Note 5 for additional information regarding our leases.
Derivatives and Risk Management Activities	Derivatives and Risk Management Activities - 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 - 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 See Note 9 for additional information regarding our hedging activities using derivatives.
Fair Value Measurement, Policy [Policy Text Block]	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. See Note 9 for additional information regarding our fair value measurements.
Property, Plant and Equipment	Property, Plant and Equipment - Our properties are stated at cost, which includes direct construction costs such as direct labor, materials, burden and AFUDC. Generally, the cost of our property retired or sold, plus removal costs, less salvage, is charged to accumulated depreciation. Gains and losses from sales or retirement of an entire operating unit or system of our properties are recognized in income. Maintenance and repairs are charged directly to expense. AFUDC represents the cost of borrowed funds used to finance construction activities. We capitalize interest costs during the construction or upgrade of qualifying assets. Capitalized interest is recorded as a reduction to interest expense. Our properties are depreciated using the straight-line method over their estimated useful lives. Generally, we apply composite depreciation rates to functional groups of property having similar economic circumstances. We periodically conduct depreciation studies to assess the economic lives of our assets. These depreciation studies are completed as a part of our regulatory proceedings, and the changes in economic lives, if applicable, are implemented prospectively when the new rates are approved by our regulators and become effective. Changes in the estimated economic lives of our property, plant and equipment could have a material effect on our financial position, results of operations or cash flows. Property, plant and equipment on our Consolidated Balance Sheets includes construction work in process for capital projects that have not yet been placed in service and therefore are not being depreciated. Assets are transferred out of construction work in process when they are substantially complete and ready for their intended use.
Impairment of Goodwill and Long-Lived Assets	Impairment of Goodwill and Long-Lived Assets - We assess our goodwill for impairment at least annually as of July 1, unless events or a change in circumstances indicate an impairment may have occurred before that time. As part of our goodwill impairment test, we first assess qualitative factors (including macroeconomic conditions, industry and market considerations, cost factors and overall financial performance) to determine whether it is more likely than not that our fair value is less than the carrying amount of our net assets. If further testing is necessary or a quantitative test is elected to refresh our recurring qualitative assessment, we perform a quantitative impairment test for goodwill. Our impairment test is made by comparing our fair value with our book value, including goodwill. If the fair value is less than the book value, an impairment is measured by the amount of our carrying value that exceeds fair value, not to exceed the carrying amount of our goodwill. To estimate fair value, we use two generally accepted valuation approaches, an income approach and a market approach, using assumptions consistent with a market participant’s perspective. Under the income approach, we use anticipated cash flows over a period of years plus a terminal value and discount these amounts to their present value using appropriate discount rates. Under the market approach, we apply acquisition multiples to forecasted cash flows. The acquisition multiples used are consistent with historical market transactions. The forecasted cash flows are based on average forecasted cash flows over a period of years. We performed a quantitative analysis in 2019, which did not result in any impairment indicators, nor did our analysis reflect our reporting unit at risk. Our goodwill impairment analysis performed in 2021 and 2020 utilized a qualitative assessment and did not result in any impairment indicators, nor did our analysis reflect our reporting unit at risk. Subsequent to July 1, 2021, no event has occurred indicating that it is more likely than not that our fair value is less than the carrying value of our net assets. We assess our long-lived assets for impairment whenever events or changes in circumstances indicate that an asset’s carrying amount may not be recoverable. An impairment is indicated if the carrying amount of a long-lived asset exceeds the sum of the undiscounted future cash flows expected to result from the use and eventual disposition of the asset. If an impairment is indicated, we record an impairment loss equal to the difference between the carrying value and the fair value of the long-lived asset. We determined that there were no material asset impairments in 2021, 2020 or 2019.
Regulation	Regulation - We are subject to the rate regulation and accounting requirements of the OCC, KCC, RRC and various municipalities in Texas. We follow the accounting and reporting guidance for regulated operations. During the ratemaking process, regulatory authorities set the framework for what we can charge customers for our services and establish the manner that our costs are accounted for, including allowing us to defer recognition of certain costs and permitting recovery of the amounts through rates over time, as opposed to expensing such costs as incurred. Examples include weather normalization, unrecovered purchased-gas costs, extraordinary costs associated with Winter Storm Uri, pension and postemployment benefit costs and ad-valorem taxes. This allows us to stabilize rates over time rather than passing such costs on to the customer for immediate recovery. Actions by regulatory authorities could have an effect on the amount recovered from customers. Any difference in the amount recoverable and the amount deferred is recorded as income or expense at the time of the regulatory action. A write-off of regulatory assets and costs not recovered may be required if all or a portion of the regulated operations have rates that are no longer: • established by independent regulators; • designed to recover our costs of providing regulated services; and • set at levels that will recover our costs when considering the demand and competition for our services. See Note 10 for additional information regarding our regulatory assets and liabilities disclosures.
Pension and Other Postretirement Plans	Pension and Other Postemployment Employee Benefits - We have defined benefit pension plans covering eligible employees. We also sponsor welfare plans that provide other postemployment medical and life insurance benefits to eligible employees who retire with at least five years of service. To calculate the costs and liabilities related to our plans, we utilize an outside actuarial consultant, which uses statistical and other factors to anticipate future events. These factors include assumptions about the discount rate, expected return on plan assets, rate of future compensation increases, age and mortality and employment periods. We use tables issued by the Society of Actuaries to estimate mortality rates. In determining the projected benefit obligations and costs, assumptions can change from period to period and may result in material changes in the cost and liabilities we recognize.
Income Taxes	Income Taxes - Deferred income taxes are recorded for the difference between the financial statement and income tax basis of assets and liabilities and carryforward items, based on income tax laws and rates existing at the time the temporary differences are expected to reverse. The effect on deferred income taxes of a change in tax rates is deferred and amortized for operations regulated by the OCC, KCC, RRC and various municipalities in Texas, if, as a result of an action by a regulator, it is probable that the effect of the change in tax rates will be recovered from or returned to customers through future rates. We continue to amortize previously deferred investment tax credits for ratemaking purposes over the periods prescribed by our regulators. A valuation allowance for deferred income tax assets is recognized when it is more likely than not that some or all of the benefit from the deferred income tax asset will not be realized. To assess that likelihood, we use estimates and judgment regarding our future taxable income, as well as the jurisdiction in which such taxable income is generated, to determine whether a valuation allowance is required. Such evidence can include our current financial position, our results of operations, both actual and forecasted, the reversal of deferred income tax liabilities, as well as the current and forecasted business economics of our industry. We had no valuation allowance at December 31, 2021 and 2020. We utilize a more-likely-than-not recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position that is taken or expected to be taken in a tax return. We reflect penalties and interest as part of income tax expense as they become applicable for tax provisions that do not meet the more-likely-than-not recognition threshold and measurement attribute. There were no material uncertain tax positions at December 31, 2021 and 2020. Changes in tax laws or tax rates are recognized in the financial reporting period that includes the enactment date. See Note 14 for additional information regarding income taxes.
Asset Retirement Obligations	Asset Retirement Obligations - Asset retirement obligations represent legal obligations associated with the retirement of long-lived assets that result from the acquisition, construction, development and/or normal use of the asset. Certain long-lived assets that comprise our natural gas distribution systems, primarily our pipeline assets, are subject to agreements or regulations that give rise to an asset retirement obligation for removal or other disposition costs associated with retiring the assets in place upon the discontinued use of the natural gas distribution system. We recognize the fair value of a liability for an asset retirement obligation in the period when it is incurred if a reasonable estimate of the fair value can be made. We are not able to estimate reasonably the fair value of the asset retirement obligations for portions of our assets because the settlement dates are indeterminable given our expected continued use of the assets with proper maintenance. We expect our natural gas distribution systems will continue in operation for the foreseeable future. Based on our proximity to significant natural gas reserves and infrastructure and the widespread use of natural gas for heating and cooking activities by residential and commercial customers in our service areas, we expect supply and demand to exist for the foreseeable future. In accordance with long-standing regulatory treatment, we collect through rates the estimated costs of removal on certain regulated properties through depreciation expense as a portion of the net salvage value component of our composite deprecation rates, with a corresponding credit to accumulated depreciation and amortization. These removal costs collected through our rates include costs attributable to legal and nonlegal removal obligations. These costs are addressed prospectively in depreciation rates, rather than as a regulatory liability, in each general rate order.
Contingencies	Contingencies - Our accounting for contingencies covers a variety of business activities, including contingencies for legal and environmental exposures. We accrue these contingencies when our assessments indicate that it is probable that a liability has been incurred or an asset will not be recovered and an amount can be estimated reasonably. We expense legal fees as incurred and base our legal liability estimates on currently available facts and our estimates of the ultimate outcome or resolution. Accruals for the estimated cost of environmental remediation obligations generally are recognized no later than the completion of a remediation feasibility study. Recoveries of environmental remediation costs from other parties are recorded as assets when their receipt is deemed probable. Actual results may differ from our estimates resulting in an impact, positive or negative, on earnings. See Note 16 for additional information regarding contingencies.
Share-Based Payments	Share-Based Payments - We expense the fair value of share-based payments net of estimated forfeitures. We estimate forfeiture rates based on historical forfeitures under our share-based payment plans.
Earnings Per Share	Earnings per share - Basic EPS is based on net income and is calculated based upon the daily weighted-average number of common shares outstanding during the periods presented. Also, this calculation includes fully vested stock awards that have not yet been issued as common stock. Diluted EPS includes the above, plus unvested stock awards granted under our compensation plans, but only to the extent these instruments dilute earnings per share.
Segments	Segments - We operate in one reportable business segment: regulated public utilities that deliver natural gas primarily to residential, commercial and transportation customers. We define reportable business segments as components of an organization for which discrete financial information is available and operating results are evaluated on a regular basis by the chief operating decision maker (“CODM”) in order to assess performance and allocate resources. Our CODM is our Chief Executive Officer. Characteristics of our organization that were relied upon in making this determination include the similar nature of services we provide, the functional alignment of our organizational structure, and the reports that are regularly reviewed by the CODM for the purpose of assessing performance and allocating resources. Our management is functionally aligned and centralized, with performance evaluated based upon results of the entire distribution business. Capital allocation decisions are driven by asset integrity management, operating efficiency, growth opportunities and government-requested pipeline relocations, not geographic location or regulatory jurisdiction. In 2021, 2020 and 2019, we had no single external customer from which we received 10 percent or more of our gross revenues.
Treasury Stock	Treasury Stock - We record treasury stock purchases at cost, which includes incremental direct transaction costs. Amounts are recorded as reductions in equity in our consolidated balance sheets. We record the reissuance of treasury stock at our weighted average cost of treasury shares recorded in equity in our consolidated balance sheets.
Recently Issues Accounting Standards Updates	Recently Issued Accounting Standards Update - In March 2020, the FASB issued ASU 2020-04, “Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting,” which provides relief from the accounting analysis and impacts that may otherwise be required for modifications to agreements (e.g., loans, debt securities, derivatives, borrowings) necessitated by reference rate reform. It also provides optional expedients to enable companies to continue to apply hedge accounting to certain hedging relationships impacted by reference rate reform. In the first quarter 2020, we adopted this new guidance effective for contracts modified between March 12, 2020 and December 31, 2022. Our revolving line of credit under the ONE Gas Credit Agreement and our floating-rate senior notes utilize LIBOR as the reference rate. If modified, we may elect the optional practical expedients to account for the modifications prospectively. Our adoption did not result in a material impact to our consolidated financial statements. In December 2019, the FASB issued ASU 2019-12, “Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes,” which removes certain exceptions for recognizing deferred taxes for investments, performing intra-period allocation and calculating income taxes in interim periods. ASU 2019-12 also adds guidance to reduce complexity in certain areas, including recognizing deferred taxes for tax goodwill and allocating taxes to members of a consolidated group. This standard is effective for interim and annual periods in fiscal years beginning after December 15, 2020. We adopted this new guidance in the first quarter of 2021 and our adoption did not result in a material impact to our financial position or results of operations or to our consolidated financial statements. In August 2018, the FASB issued ASU 2018-15, “Intangibles - Goodwill and Other - Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Implementation Costs Incurred in a Cloud Computing Arrangement That Is a Service Contract (a consensus of the FASB Emerging Issues Task Force).” Under this guidance, a company should defer implementation costs that it incurs if a company would capitalize those same costs under the internal-use software guidance for an arrangement that is a software license. The deferred implementation costs should be amortized over the term of the hosting arrangement, including any probable renewals. We are party to hosting arrangements identified as service contracts for various information systems used in our operations. We adopted this new guidance using the prospective transition approach for implementation costs incurred in hosting arrangement service contracts beginning January 1, 2020. In certain jurisdictions, we have orders from our regulators allowing us to amortize deferred implementation costs for hosting arrangements entered into after January 1, 2020, over the life approved by our regulators for our internal-use software systems rather than the term of the hosting arrangement. The difference in amortization calculated between the term of the hosting arrangement and internal-use software life approved by our regulators is deferred as a regulatory asset and amortized over the remaining internal-use software life that exceeds the term of the hosting arrangement. Our adoption did not result in a material impact to our consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-14, an amendment to ASC 715, “Compensation - Retirement Benefits.” This guidance eliminates requirements for certain disclosures such as the amount and timing of plan assets expected to be returned to the employer and the amount of future annual benefits covered by insurance contracts. The standard is effective for periods ending after December 15, 2020, and we adopted this guidance in the first quarter 2020. The guidance added new disclosure requirements for sponsors of the defined benefit plans to provide information relating to the weighted-average interest crediting rate for cash balance plans and other plans with promised interest crediting rates and an explanation for significant gains or losses related to changes in the benefit obligations for the period. We have reflected these changes as presented in Note 13 to our consolidated financial statements. In August 2018, the FASB issued ASU No. 2018-13, “Fair Value Measurement (Topic 820): Disclosure Framework - Changes to the Disclosure Requirements for Fair Value Measurement,” which removes, modifies and adds to certain disclosure requirements of fair value measurements. The guidance was effective for the Company beginning January 1, 2020, and we adopted this guidance in the first quarter 2020. Disclosure requirements removed include the amount of and reasons for transfers between Level 1 and Level 2 of the fair value hierarchy, the policy for timing of transfers between levels and the valuation processes for Level 3 fair value measurements. Modifications include considerations around the requirement to disclose the timing of liquidation of an investee’s assets and the date when restrictions from redemption might lapse. The additions include the requirement to disclose changes in unrealized gains and losses for the period in other comprehensive income for recurring Level 3 fair value measurements held and the range and weighted average of significant unobservable inputs used to develop Level 3 fair value measurements. The guidance did not have a material impact on the Company’s fair value disclosure, and we have reflected these changes as presented in Note 13 to our consolidated financial statements. In February 2018, the FASB issued ASU 2018-02, “Income Statement - Reporting Comprehensive Income (Topic 220): Reclassification of Certain Tax Effects from Accumulated Other Comprehensive Income,” which allows a reclassification from accumulated other comprehensive income (loss) to retained earnings for stranded tax effects resulting from the Tax Cuts and Jobs Act of 2017. We adopted this new guidance in the first quarter 2019 and our adoption did not result in a material impact to our consolidated financial statements. This change is reflected in our consolidated statements of equity. In June 2016, the FASB issued ASU 2016-13, “Financial Instruments - Credit Losses: Measurement of Credit Losses on Financial Instruments,” which introduces new guidance to the accounting for credit losses on instruments within its scope, including trade receivables. We adopted this new guidance in the first quarter 2020 using the modified retrospective method. Our financial assets within scope of this guidance primarily include our trade receivables from customers. Our policy for measuring our allowance for doubtful accounts is disclosed in the aforementioned policy for accounts receivable. We did not create any new accounting policies, nor did we modify any of our existing policies, as a result of adopting this guidance. Our adoption did not result in a cumulative adjustment to our opening retained earnings or have a material impact to our consolidated financial statements.

REVENUE (Tables)

REVENUE (Tables)	12 Months Ended
	Dec. 31, 2021
Revenues Disaggregated by Source [Table]	The following table sets forth our revenues disaggregated by source for the periods indicated: Year Ended December 31, 2021 2020 2019 (Thousands of dollars) Natural gas sales to customers $ 1,652,566 $ 1,381,141 $ 1,512,886 Transportation revenues 118,492 113,855 114,014 Miscellaneous revenues 16,757 15,505 20,579 Total revenues from contracts with customers 1,787,815 1,510,501 1,647,479 Other revenues - natural gas sales related 9,650 8,299 (4,699) Other revenues 11,132 11,468 9,950 Total other revenues 20,782 19,767 5,251 Total revenues $ 1,808,597 $ 1,530,268 $ 1,652,730

LEASES (Tables)

LEASES (Tables)	12 Months Ended
	Dec. 31, 2021
Leases [Abstract]
Other Information Related to Operating Leases [Table Text Block]	Years Ended December 31, Other information related to operating leases 2021 2020 2019 (Millions of dollars) Weighted-average remaining lease term 6 years 7 years 7 years Weighted-average discount rate 2.78 % 2.81 % 3.62 % Supplemental cash flows information Lease payments $ (8.0) $ (8.0) $ (8.4) Right-of-use assets obtained in exchange for lease obligations $ 0.4 $ 9.8 $ 9.5
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	December 31, Future minimum lease payments under non-cancellable operating leases 2021 (Millions of dollars) 2022 $ 7.5 2023 6.3 2024 4.8 2025 4.1 2026 3.3 Thereafter 7.7 Total future minimum lease payments $ 33.7 Imputed interest (2.5) Total operating lease liability $ 31.2 Consolidated balance sheets as of December 31, 2021 Current operating lease liability $ 6.8 Long-term operating lease liability 24.4 Total operating lease liability $ 31.2

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	12 Months Ended
	Dec. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Line Items]
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table sets forth the balance in accumulated other comprehensive loss for the periods indicated: Accumulated Other Comprehensive Loss (Thousands of dollars) January 1, 2020 $ (6,739) Pension and other postemployment benefit plans obligations Other comprehensive income before reclassification, net of tax of $587 (1,932) Amounts reclassified from accumulated other comprehensive loss, net of tax of $(298) 894 Other comprehensive loss (1,038) December 31, 2020 (7,777) Pension and other postemployment benefit plans obligations Other comprehensive loss before reclassification, net of tax of $11 78 Amounts reclassified from accumulated other comprehensive loss, net of tax of $(390) 1,172 Other comprehensive income 1,250 December 31, 2021 (6,527)
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	The following table sets forth the effect of reclassifications from accumulated other comprehensive loss on our Consolidated Statements of Income for the periods indicated: Affected Line Item in the Details about Accumulated Other Comprehensive Years Ended December 31, Consolidated Statements of Loss Components 2021 2020 2019 Income ( Thousands of dollars ) Pension and other postemployment benefit plan obligations (a) Amortization of net loss $ 45,896 $ 42,492 $ 35,283 Amortization of unrecognized prior service cost (279) (117) (673) 45,617 42,375 34,610 Regulatory adjustments (b) (44,055) (41,183) (33,758) 1,562 1,192 852 Income before income taxes (390) (298) (213) Income tax expense Total reclassifications for the period $ 1,172 $ 894 $ 639 Net income (a) These components of accumulated other comprehensive loss are included in the computation of net periodic benefit cost. See Note 13 for additional information regarding 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 10 for additional information regarding our regulatory assets and liabilities.

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	12 Months Ended
	Dec. 31, 2021
EARNINGS PER SHARE OF COMMON STOCK, BASIC AND DILUTED [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: Year Ended December 31, 2021 Income Shares Per Share ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 206,434 53,575 $ 3.85 Diluted EPS Calculation Effect of dilutive securities — 99 Net income available for common stock and common stock equivalents $ 206,434 53,674 $ 3.85 Year Ended December 31, 2020 Income Shares Per Share ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 196,412 53,133 $ 3.70 Diluted EPS Calculation Effect of dilutive securities — 237 Net income available for common stock and common stock equivalents $ 196,412 53,370 $ 3.68 Year Ended December 31, 2019 Income Shares Per Share ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 186,749 52,895 $ 3.53 Diluted EPS Calculation Effect of dilutive securities — 345 Net income available for common stock and common stock equivalents $ 186,749 53,240 $ 3.51

REGULATORY ASSETS AND LIABILI_2

REGULATORY ASSETS AND LIABILITIES (Tables)	12 Months Ended
	Dec. 31, 2021
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES	The tables below present a summary of regulatory assets, net of amortization, and liabilities for the periods indicated: December 31, 2021 Remaining Recovery Period Current Noncurrent Total ( Thousands of dollars ) Winter weather event costs (a) $ 1,536,054 $ 428,023 $ 1,964,077 Under-recovered purchased-gas costs 1 year 31,863 — 31,863 Pension and other postemployment benefit costs See Note 13 11,507 260,559 272,066 Reacquired debt costs 6 years 812 4,070 4,882 MGP remediation costs 15 years 98 29,841 29,939 Ad-valorem tax 1 year 8,561 — 8,561 WNA 1 year 10,044 — 10,044 Customer credit deferrals 1 year 10,685 — 10,685 Other 1 to 18 years 2,052 2,369 4,421 Total regulatory assets, net of amortization 1,611,676 724,862 2,336,538 Income tax rate changes (a) — (552,928) (552,928) Over-recovered purchased-gas costs 1 year (8,090) — (8,090) Total regulatory liabilities (8,090) (552,928) (561,018) Net regulatory assets and liabilities $ 1,603,586 $ 171,934 $ 1,775,520 (a) Recovery period varies by jurisdiction. See discussion below for additional information regarding our regulatory assets related to winter weather event costs and regulatory liabilities related to federal income tax rate changes. December 31, 2020 Remaining Recovery Period Current Noncurrent Total ( Thousands of dollars ) Under-recovered purchased-gas costs 1 year $ 16,502 $ — $ 16,502 Pension and other postemployment benefit costs See Note 13 16,541 341,266 357,807 Reacquired debt costs 7 years 812 4,866 5,678 MGP remediation costs 15 years 98 18,711 18,809 Ad-valorem tax 1 year 5,558 — 5,558 WNA 1 year 4,806 — 4,806 Customer credit deferrals 1 year 10,267 — 10,267 Other 1 to 18 years 2,189 2,113 4,302 Total regulatory assets, net of amortization 56,773 366,956 423,729 Income tax rate changes (a) — (547,563) (547,563) Over-recovered purchased-gas costs 1 year (15,761) — (15,761) Total regulatory liabilities (15,761) (547,563) (563,324) Net regulatory assets and liabilities $ 41,012 $ (180,607) $ (139,595)

PROPERTY, PLANT AND EQUIPMENT_2

PROPERTY, PLANT AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2021
Regulated [Member]
Entity Information
Property, Plant and Equipment by Property Type	The following table sets forth our property, plant and equipment by property type, for the periods indicated: December 31, December 31, 2021 2020 ( Thousands of dollars ) Natural gas distribution pipelines and related equipment $ 5,836,066 $ 5,517,488 Natural gas transmission pipelines and related equipment 624,528 586,360 General plant and other 712,659 657,037 Construction work in process 101,015 77,718 Property, plant and equipment 7,274,268 6,838,603 Accumulated depreciation and amortization (2,083,433) (1,971,546) Net property, plant and equipment $ 5,190,835 $ 4,867,057

SHARE-BASED PAYMENTS (Tables)

SHARE-BASED PAYMENTS (Tables)	12 Months Ended
	Dec. 31, 2021
Share-based Payments [Line Items]
Schedule of Share-based Compensation, Restricted Stock Units Activity	The following tables set forth activity and various statistics for restricted stock unit awards outstanding under the respective plans for the period indicated: Number of Weighted- Nonvested at December 31, 2020 99,800 $ 82.29 Granted 50,353 $ 72.69 Vested (42,821) $ 71.67 Forfeited (13,058) $ 81.07 Nonvested at December 31, 2021 94,274 $ 82.16 2021 2020 2019 Weighted-average grant date fair value (per share) $ 72.69 $ 96.21 $ 83.94 Fair value of shares granted (thousands of dollars) $ 3,660 $ 3,005 $ 3,001
Schedule of Nonvested Performance-based Units Activity	The following tables set forth activity and various statistics related to our performance stock unit awards and the assumptions used by us in the valuations of the 2021, 2020 and 2019 grants at the grant date: Number of Weighted- Nonvested at December 31, 2020 208,520 $ 87.97 Granted 107,381 $ 82.51 Vested (76,483) $ 74.04 Forfeited (40,819) $ 89.19 Nonvested at December 31, 2021 198,599 $ 90.13 2021 2020 2019 Volatility (a) 32.70% 16.40% 18.70% Dividend yield 3.19% 2.25% 2.38% Risk-free interest rate (b) 0.20% 1.40% 2.50% (a) - Volatility based on historical volatility over three years using daily stock price observations of our peer utilities. (b) - Using 3-year treasury. 2021 2020 2019 Weighted-average grant date fair value (per share) $ 82.51 $ 102.77 $ 89.86 Fair value of shares granted (thousands of dollars) $ 8,860 $ 6,502 $ 6,401

EMPLOYEE BENEFIT PLANS (Tables)

EMPLOYEE BENEFIT PLANS (Tables)	12 Months Ended
	Dec. 31, 2021
Defined Benefit Plans and Other Postemployment Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Assumptions [Table Text Block]	Actuarial Assumptions - The following table sets forth the weighted-average assumptions used to determine benefit obligations for pension and postemployment benefits for the periods indicated: December 31, 2021 2020 Discount rate - pension plans 3.05% 2.80% Discount rate - other postemployment plans 3.00% 2.70% Compensation increase rate 3.10% - 5.00% 3.10% - 3.90% The following table sets forth the weighted-average assumptions used by us to determine the periodic benefit costs for the periods indicated: Years Ended December 31, 2021 2020 2019 Discount rate - pension plans 2.80% 3.50% 4.40% Discount rate - other postemployment plans 2.70% 3.40% 4.40% Expected long-term return on plan assets - pension plans 7.15% 7.20% 7.20% Expected long-term return on plan assets - other postemployment plans 7.50% 7.65% 7.35% Compensation increase rate 3.10% - 3.90% 3.10% - 4.00% 3.20% - 4.00%
Schedule of Defined Benefit Plans Disclosures [Table Text Block]	The following table sets forth our defined benefit pension and other postemployment benefit plans, benefit obligations and fair value of plan assets for the periods indicated: Pension Benefits Other Postemployment Benefits December 31, December 31, 2021 2020 2021 2020 Changes in Benefit Obligation (Thousands of dollars) Benefit obligation, beginning of period $ 1,077,641 $ 1,001,368 $ 239,530 $ 230,490 Service cost 13,811 12,869 1,587 1,692 Interest cost 29,458 34,179 6,251 7,557 Plan participants’ contributions — — 3,226 3,500 Actuarial loss (gain) (19,587) 91,566 (8,894) 14,013 Benefits paid (51,333) (62,341) (18,894) (17,722) Benefit obligation, end of period 1,049,990 1,077,641 222,806 239,530 Change in Plan Assets Fair value of plan assets, beginning of period 987,583 907,974 230,895 207,182 Actual return (loss) on plan assets 75,999 140,939 14,786 35,837 Employer contributions 995 1,011 1,981 2,098 Plan participants’ contributions — — 3,226 3,500 Benefits paid (51,333) (62,341) (18,894) (17,722) Settlements — — — — Fair value of assets, end of period 1,013,244 987,583 231,994 230,895 Benefit Asset (Obligation), net at December 31 $ (36,746) $ (90,058) $ 9,188 $ (8,635) Other noncurrent assets — — 9,188 — Current liabilities (1,521) (1,056) — — Noncurrent liabilities (35,225) (89,002) — (8,635) Benefit Asset (Obligation), net at December 31 $ (36,746) $ (90,058) $ 9,188 $ (8,635)
Schedule of Net Benefit Costs [Table Text Block]	Components of Net Periodic Benefit Cost - The following tables set forth the components of net periodic benefit cost, prior to regulatory deferrals, for our defined benefit pension and other postemployment benefit plans for the period indicated: Pension Benefits Year Ended December 31, 2021 2020 2019 (Thousands of dollars) Components of net periodic benefit cost Service cost $ 13,811 $ 12,869 $ 12,030 Interest cost (a) 29,458 34,179 40,670 Expected return on assets (a) (62,382) (61,119) (61,939) Amortization of net loss (a) 45,523 42,319 33,039 Net periodic benefit cost $ 26,410 $ 28,248 $ 23,800 (a) These amounts, net of any amounts capitalized as a regulatory asset since adoption of ASU 2017-07 on January 1, 2018, have been recognized as other income (expense), net in the Consolidated Statements of Income. See Note 15 for additional detail of our other income (expense), net. Other Postemployment Benefits Year Ended December 31, 2021 2020 2019 (Thousands of dollars) Components of net periodic benefit cost Service cost $ 1,587 $ 1,692 $ 1,734 Interest cost (a) 6,251 7,557 9,318 Expected return on assets (a) (16,807) (15,469) (12,586) Amortization of unrecognized prior service cost (a) (279) (117) (673) Amortization of net loss (a) 373 173 2,244 Net periodic benefit cost (credit) $ (8,875) $ (6,164) $ 37
Schedule of Amounts Recognized in Other Comprehensive Income (Loss) [Table Text Block]	Other Comprehensive Income (Loss) - The following table sets forth the amounts recognized in other comprehensive income (loss), net of regulatory deferrals, related to our defined benefit pension benefits for the period indicated: Pension Benefits Year Ended December 31, 2021 2020 2019 (Thousands of dollars) Net gain (loss) arising during the period $ 67 $ (2,519) $ (2,766) Amortization of loss 1,562 1,192 852 Deferred income taxes (379) 289 479 Total recognized in other comprehensive income (loss) $ 1,250 $ (1,038) $ (1,435)
Schedule of Net Periodic Benefit Cost Not yet Recognized [Table Text Block]	The tables below set forth the amounts in accumulated other comprehensive loss that had not yet been recognized as components of net periodic benefit expense for the periods indicated: Pension Benefits December 31, 2021 2020 (Thousands of dollars) Accumulated loss $ (272,332) $ (351,059) Accumulated other comprehensive loss (272,332) (351,059) Regulatory asset for regulated entities 264,027 341,125 Accumulated other comprehensive loss (8,305) (9,934) Deferred income taxes 1,778 2,157 Accumulated other comprehensive loss, $ (6,527) $ (7,777) Other Postemployment Benefits December 31, 2021 2020 (Thousands of dollars) Prior service credit $ (194) $ 85 Accumulated loss (5,887) (13,134) Accumulated other comprehensive loss $ (6,081) $ (13,049) Regulatory asset for regulated entities 6,081 13,049 Accumulated other comprehensive loss $ — $ —
Schedule of Health Care Cost Trend Rates [Table Text Block]	Health Care Cost Trend Rates - The following table sets forth the assumed health care cost-trend rates for the periods indicated: 2021 2020 Health care cost-trend rate assumed for next year 6.00% 6.25% Rate to which the cost-trend rate is assumed to decline 4.50% 4.50% Year that the rate reaches the ultimate trend rate 2028 2026
Schedule of Allocation of Plan Assets [Table Text Block]	Plan Assets - Our investment strategy is to invest plan assets in accordance with sound investment practices that emphasize long-term fundamentals. The goal of this strategy is to maximize investment returns while managing risk in order to meet the plan’s current and projected financial obligations. To achieve this strategy, we have established a liability-driven investment strategy to change the allocations as the funded status of the defined benefit pension plan increases. The plan’s investments include a diverse blend of various domestic and international equities, investment-grade debt securities which mirror the cash flows of our liability, insurance contracts and alternative investments. The current target allocation for the assets of our defined benefit pension plan is as follows: Investment-grade bonds 60.0 % U.S. large-cap equities 14.0 % Alternative investments 10.0 % Developed foreign large-cap equities 7.0 % Mid-cap equities 5.0 % Emerging markets equities 1.0 % Small-cap equities 3.0 % Total 100 % As part of our risk management for the plans, minimums and maximums have been set for each of the asset classes listed above. All investment managers for the plan are subject to certain restrictions on the securities they purchase and, with the exception of indexing purposes, are prohibited from owning our stock. The current target allocation for the assets of our other postemployment benefits plan is 65 percent fixed income securities and 35 percent equity securities. The following tables set forth our pension benefits and other postemployment benefits plan assets by fair value category as of the measurement date: Pension Benefits December 31, 2021 Asset Category Level 1 Level 2 Level 3 Total (Thousands of dollars) Investments: Equity securities (a) $ 223,871 $ — $ — $ 223,871 Government obligations — 205,741 — 205,741 Corporate obligations (b) — 440,445 — 440,445 Cash and money market funds (c) 3,864 30,546 — 34,410 Insurance contracts and group annuity contracts — — 17,301 17,301 Other investments (d) — 20 91,456 91,476 Total assets $ 227,735 $ 676,752 $ 108,757 $ 1,013,244 (a) - This category represents securities of the various market sectors from diverse industries. (b) - This category represents bonds from diverse industries. (c) - This category primarily represents money market funds. (d) - This category represents alternative investments such as hedge funds and other financial instruments. Pension Benefits December 31, 2020 Asset Category Level 1 Level 2 Level 3 Total (Thousands of dollars) Investments: Equity securities (a) $ 392,639 $ 35,454 $ — $ 428,093 Government obligations — 78,080 — 78,080 Corporate obligations (b) — 343,118 — 343,118 Cash and money market funds (c) 1,589 23,311 — 24,900 Insurance contracts and group annuity contracts — — 24,603 24,603 Other investments (d) — 1,155 87,634 88,789 Total assets $ 394,228 $ 481,118 $ 112,237 $ 987,583 (a) - This category represents securities of the various market sectors from diverse industries. (b) - This category represents bonds from diverse industries. (c) - This category primarily represents money market funds. (d) - This category represents alternative investments such as hedge funds and other financial instruments. Other Postemployment Benefits December 31, 2021 Asset Category Level 1 Level 2 Level 3 Total (Thousands of dollars) Investments: Equity securities (a) $ 25,577 $ — $ — $ 25,577 Government obligations — 41,366 — 41,366 Corporate obligations (b) — 41,601 — 41,601 Cash and money market funds (c) 542 12,990 — 13,532 Insurance contracts and group annuity contracts (d) — 109,918 — 109,918 Total assets $ 26,119 $ 205,875 $ — $ 231,994 (a) - This category represents securities of the various market sectors from diverse industries. (b) - This category represents bonds from diverse industries. (c) - This category primarily represents money market funds. (d) - This category includes equity securities and bonds held in a captive insurance product. Other Postemployment Benefits December 31, 2020 Asset Category Level 1 Level 2 Level 3 Total (Thousands of dollars) Investments: Equity securities (a) $ 73,578 $ — $ — $ 73,578 Government obligations — — — — Corporate obligations (b) — 39,115 — 39,115 Cash and money market funds (c) 52 8,071 — 8,123 Insurance contracts and group annuity contracts (d) — 110,079 — 110,079 Total assets $ 73,630 $ 157,265 $ — $ 230,895 (a) - This category represents securities of the various market sectors from diverse industries. (b) - This category represents bonds from diverse industries. (c) - This category primarily represents money market funds. (d) - This category includes equity securities and bonds held in a captive insurance product.
Schedule of Employee Pension Plans Investments at Fair Value	The following tables set forth additional information regarding commitments and redemption limitations of these other investments at the periods indicated: December 31, 2021 Fair Value Unfunded Commitments Redemption Frequency Redemption Notice Period (in thousands) (in days) Grosvenor Registered Multi Limited Partnership $ 44,818 $ — quarterly 65 K2 Institutional Investors II Limited Partnership $ 46,638 $ — quarterly 91 December 31, 2020 Fair Value Unfunded Commitments Redemption Frequency Redemption Notice Period (in thousands) (in days) Grosvenor Registered Multi Limited Partnership $ 42,632 $ — quarterly 65 K2 Institutional Investors II Limited Partnership $ 45,002 $ — quarterly 91
Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets [Table Text Block]	The following table sets forth the reconciliation of Level 3 fair value measurements of our pension plans for the periods indicated: Pension Benefits Insurance Other Total (Thousands of dollars) January 1, 2020 $ 25,988 $ 81,793 $ 107,781 Unrealized gains 1,764 4,849 6,613 Purchases — 992 992 Settlements (3,149) — (3,149) December 31, 2020 $ 24,603 $ 87,634 $ 112,237 Unrealized gains — 1,625 1,625 Unrealized losses (3,368) — (3,368) Purchases — 2,197 2,197 Settlements (3,934) — (3,934) December 31, 2021 $ 17,301 $ 91,456 $ 108,757
Schedule of Expected Benefit Payments [Table Text Block]	The following table sets forth the pension benefits and other postemployment benefits payments expected to be paid in 2022-2031: Pension Other Postemployment Benefits to be paid in: (Thousands of dollars) 2022 $ 52,936 $ 15,744 2023 $ 53,745 $ 15,571 2024 $ 54,440 $ 15,184 2025 $ 55,075 $ 14,940 2026 $ 55,852 $ 14,580 2027 through 2031 $ 283,344 $ 67,566

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2021
Income tax [Line Items]
Reconciliation of Income Tax Provision	The following table sets forth our provision for income taxes for the periods indicated: Years Ended December 31, 2021 2020 2019 ( Thousands of dollars ) Current income tax provision (benefit) Federal $ (1,568) $ 20,129 $ 24,537 State (1,565) 2,965 5,008 Total current income tax provision (benefit) (3,133) 23,094 29,545 Deferred income tax provision Federal 37,810 10,757 8,375 State 5,639 7,728 4,932 Total deferred income tax provision 43,449 18,485 13,307 Total provision for income taxes $ 40,316 $ 41,579 $ 42,852
Schedule of Effective Income Tax Rate Reconciliation	The following table is a reconciliation of our income tax provision for the periods indicated: Years Ended December 31, 2021 2020 2019 ( Thousands of dollars ) Income before income taxes $ 246,750 $ 237,991 $ 229,601 Federal statutory income tax rate 21 % 21 % 21 % Provision for federal income taxes 51,817 49,978 48,215 State income taxes, net of federal tax benefit 4,074 10,693 9,758 Amortization of EDIT regulatory liability (17,289) (17,031) (12,828) Tax benefit of employee share-based compensation (469) (1,489) (2,116) Other, net 2,183 (572) (177) Total provision for income taxes $ 40,316 $ 41,579 $ 42,852
Schedule of Deferred Tax Assets and Liabilities	The following table sets forth the tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and liabilities for the periods indicated: December 31, 2021 2020 ( Thousands of dollars ) Deferred tax assets Employee benefits and other accrued liabilities $ 11,126 $ 28,127 Regulatory adjustments for enacted tax rate changes 120,051 121,738 Net operating loss 424,861 — Lease obligation basis 6,906 9,319 Other 12,597 4,790 Total deferred tax assets 575,541 163,974 Deferred tax liabilities Excess of tax over book depreciation 734,051 717,492 Winter weather event costs 421,070 — Purchased-gas cost adjustment - other 37,433 5,240 Other regulatory assets and liabilities, net 71,541 88,260 Right-of-use asset basis 6,730 9,788 Total deferred tax liabilities 1,270,825 820,780 Net deferred tax liabilities $ 695,284 $ 656,806

Other Income and Expenses (Tabl

Other Income and Expenses (Tables)	12 Months Ended
	Dec. 31, 2021
Other Income and Expenses [Abstract]
Schedule of Other Nonoperating Income (Expense)	The following table sets forth the components of other income and other expense for the periods indicated: Years Ended December 31, 2021 2020 2019 ( Thousands of dollars ) Net periodic benefit cost other than service cost $ (3,930) $ (5,071) $ (5,895) Earnings on investments associated with nonqualified employee benefit plans 3,699 4,616 5,268 Other, net (2,976) (2,565) (2,349) Total other expense, net $ (3,207) $ (3,020) $ (2,976)

SUMMARY OF SIGNIFICANT ACCOUN_3

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)	Dec. 31, 2019USD ($)
Significant Accounting Policies [Line Items]
Number of natural gas distribution services customers	2,200,000
Unbilled Receivables, Current	$ 183,200	$ 144,900
Accounts Receivable, Allowance for Credit Loss, Current	18,700	16,600
Asset Impairment Charges	0	0	$ 0
Goodwill, Impairment Loss	0	0	$ 0
Deferred Tax Assets, Valuation Allowance	0	0
Liability for Uncertainty in Income Taxes, Current	$ 0	$ 0
Segment Reporting, Disclosure of Major Customer	0

REVENUE (Details)

REVENUE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Regulated Operating Revenue, Gas	$ 1,787,815	$ 1,510,501	$ 1,647,479
Regulated Operating Revenue, Other	11,132	11,468	9,950
Regulated Operating Revenue	1,808,597	1,530,268	1,652,730
Natural gas sales to customers [Member]
Regulated Operating Revenue, Gas	1,652,566	1,381,141	1,512,886
Transportation revenues [Member]
Regulated Operating Revenue, Gas	118,492	113,855	114,014
Miscellaneous revenues [Member]
Regulated Operating Revenue, Gas	16,757	15,505	20,579
Other revenues - natural gas sales related [Member]
Other revenues - natural gas sales related	9,650	8,299	(4,699)
Other revenues [Member]
Regulated Operating Revenue, Other	$ 20,782	$ 19,767	$ 5,251

CREDIT FACILITY AND SHORT-TER_2

CREDIT FACILITY AND SHORT-TERM NOTES PAYABLE (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 1,000,000
Line of Credit Facility Sublimit	20,000
Swingline subfacility	60,000
Line of Credit Facility Option to Increase Borrowing Capacity	$ 500,000
Line of Credit Facility, Interest Rate Description	The ONE Gas Credit Agreement utilizes LIBOR as the reference rate for determining interest to accrue on the borrowings. In the event LIBOR is not available, and such circumstances are unlikely to be temporary, our lenders may establish an alternative interest rate for the senior notes by replacing LIBOR with one or more secured overnight financing-based rates or another alternate benchmark rate.
Approved Debt to Capital Ratio through December 31, 2021	0.725
Approved Debt to Capital Ratio After December 31, 2021	0.70
Ratio of Indebtedness to Net Capital	0.64
Letters of Credit Outstanding, Amount	$ 1,200
Short-term Debt	0
Line of Credit Facility, Remaining Borrowing Capacity	998,800
Commercial paper maximum borrowing capacity	1,000,000
Commercial Paper	$ 494,000	$ 418,225
Short-term Debt, Weighted Average Interest Rate, over Time	0.38%	0.18%

LONG-TERM DEBT (Details)

LONG-TERM DEBT (Details) - USD ($) $ in Thousands	Sep. 21, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Mar. 31, 2021
Debt Instrument [Line Items]
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate		0.81%
Repayments of Long-term Debt		$ 400,000	$ 0	$ 0
Debt Instrument, Covenant Compliance, Default Provision, Indebtnedness Threshold		$ 100,000
Debt Instrument, Covenant Compliance, Default Provision, Debt Holders		0.25
Debt Instrument, Redemption Price, Percentage		100.00%
Debt Instrument, Covenant Description		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 the aggregate principal amount of the outstanding Senior Notes to declare those senior notes immediately due and payable in full.
Debt Instrument, Call Feature		We may redeem our Senior Notes at par, plus accrued and unpaid interest to the redemption date, starting one month, three months, and six months, respectively, 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 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.
Notes Payable at 0.85% Due 2023
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 1,000,000
Debt Instrument, Interest Rate, Stated Percentage		0.85%
OGS Note Payable at 1.10% Due 2024
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 700,000
Debt Instrument, Interest Rate, Stated Percentage		1.10%
OGS Note Payable with Floating-Rate Due 2023
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 400,000			$ 800,000
Debt Instrument, Interest Rate Terms		The floating-rate senior notes bear interest at a rate equal to three-month LIBOR plus 61 basis points per year reset quarterly for the applicable interest period (
Repayments of Long-term Debt	$ 400,000
Note Payable Due 2030 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 300,000
Debt Instrument, Interest Rate, Stated Percentage		2.00%
Note Payable Due 2024 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 300,000
Debt Instrument, Interest Rate, Stated Percentage		3.61%
Notes Payable Due 2044 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 600,000
Debt Instrument, Interest Rate, Stated Percentage		4.658%
Note Payable Due 2048 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross		$ 400,000
Debt Instrument, Interest Rate, Stated Percentage		4.50%

LEASES (Details)

LEASES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Option to Extend	10 years
Operating Lease, Expense	$ 8.2	$ 8.4	$ 8.5
Right-of-Use Asset Obtained in Exchange for Operating Lease Liability	0.4	$ 9.8	$ 9.5
Lease Obligation Incurred	$ 0.4
Operating Lease, Weighted Average Remaining Lease Term	6 years	7 years	7 years
Operating Lease, Weighted Average Discount Rate, Percent	2.78%	2.81%	3.62%
Operating Lease, Payments	$ (8)	$ (8)	$ (8.4)
Lessee, Operating Lease, Liability, Payments, Due Next Twelve Months	7.5
Lessee, Operating Lease, Liability, Payments, Due Year Two	6.3
Lessee, Operating Lease, Liability, Payments, Due Year Three	4.8
Lessee, Operating Lease, Liability, Payments, Due Year Four	4.1
Lessee, Operating Lease, Liability, Payments, Due Year Five	3.3
Lessee, Operating Lease, Liability, Payments, Due after Year Five	7.7
Lessee, Operating Lease, Liability, Payments, Due	33.7
Lessee, Operating Lease, Liability, Undiscounted Excess Amount	(2.5)
Operating Lease, Liability	31.2
Other Assets
Lessee, Lease, Description [Line Items]
Operating Lease, Right-of-Use Asset	30.9	$ 37.2
Other Noncurrent Liabilities
Lessee, Lease, Description [Line Items]
Operating Lease, Liability, Noncurrent	24.4
Other Current Liabilities
Lessee, Lease, Description [Line Items]
Operating Lease, Liability, Current	$ 6.8
Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	1 year
Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee, Operating Lease, Term of Contract	8 years

EQUITY (Details)

EQUITY (Details) - USD ($)	3 Months Ended									12 Months Ended
	Mar. 31, 2022	Dec. 31, 2021	Sep. 30, 2021	Jun. 30, 2021	Mar. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Preferred Stock, Shares Authorized		50,000,000								50,000,000
Preferred Stock, Par or Stated Value Per Share		$ 0.01								$ 0.01
Common stock authorized and available for issuance		196,400,000								196,400,000
Stock Repurchase Program, Authorized Amount		$ 20,000,000								$ 20,000,000
At-the-Market Equity Program, Aggregate Offering Price Limit										250,000,000
At the Market Equity Program Shares Issued										281,124	$ 179,514
At-the-Market Equity Program, Gross Proceeds										21,400,000	13,600,000
At-the-Market Equity Program, Proceeds Net of Issuance Costs										21,100,000	$ 13,500,000
At-the-Market Equity Program, Equity Available for Issuance										$ 215,000,000
Dividends declared per share of stock		$ 0.58	$ 0.58	$ 0.58	$ 0.58	$ 0.54	$ 0.54	$ 0.54	$ 0.54	$ 2.32	$ 2.16	$ 2
Common Stock, Dividends, Declared, Annualized Basis										$ 2.32	$ 2.16	$ 2
Dividend Declared [Member]
Common Stock, Dividends, Per Share, Declared	$ 0.62
Common Stock, Dividends, Declared, Annualized Basis	$ 2.48

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), beginning balance	$ (7,777)	$ (6,739)
Pension and other postretirement benefit plans obligations [Abstract]
Other comprehensive income (loss), before reclassification, net of tax	78	(1,932)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax	1,172	894
Other comprehensive income (loss), net of tax	1,250	(1,038)	$ (1,435)
Accumulated Other Comprehensive Income (Loss), ending balance	(6,527)	(7,777)	(6,739)
Pension and other postretirement benefit plans obligations [Abstract]
Amortization of net loss	45,896	42,492	35,283
Amortization of unrecognized prior service cost	(279)	(117)	(673)
Other comprehensive income (loss) reclassification adjustment, before tax and regulatory adjustments	45,617	42,375	34,610
Other comprehensive income (loss) reclassification - regulatory adjustments	(44,055)	(41,183)	(33,758)
Other comprehensive income (loss) reclassification adjustment, before tax	1,562	1,192	852
Other comprehensive income (loss) reclassification adjustment, Tax	(390)	(298)	(213)
Other comprehensive income (loss) reclassification adjustment, net of tax	1,172	894	$ 639
Other Comprehensive Income (Loss) before Reclassifications, Tax	11	587
Reclassification from AOCI, Current Period, Tax	$ 390	$ 298

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
EARNINGS PER SHARE OF COMMON STOCK, BASIC AND DILUTED [Line Items]
Net income	$ 206,434	$ 196,412	$ 186,749
Weighted Average Number of Shares Outstanding, Basic	53,575	53,133	52,895
Earnings Per Share, Basic	$ 3.85	$ 3.70	$ 3.53
Dilutive Securities, Effect on Basic Earnings Per Share	$ 0	$ 0	$ 0
Weighted Average Number Diluted Shares Outstanding Adjustment	99	237	345
Net Income (Loss) Available to Common Stockholders, Diluted	$ 206,434	$ 196,412	$ 186,749
Weighted Average Number of Shares Outstanding, Diluted	53,674	53,370	53,240
Earnings Per Share, Diluted	$ 3.85	$ 3.68	$ 3.51

DERIVATIVE FINANCIAL INSTRUME_2

DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Details)	12 Months Ended
	Dec. 31, 2021USD ($)Bcf	Dec. 31, 2020USD ($)Bcf
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative, Nonmonetary Notional Amount | Bcf	13.2	14.7
Premiums recorded in other current assets on natural gas contracts held	$ 9,500,000	$ 6,700,000
Fair Value Assets, Transfers between Levels	0	0
Corporate bonds in other assets	6,900,000	1,600,000
Treasury notes in other assets	3,500,000	3,200,000
Long-term Debt	3,700,000,000	1,600,000,000
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value of natural gas call options held	2,300,000	800,000
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Long-term Debt, Fair Value	$ 3,900,000,000	$ 2,000,000,000

REGULATORY ASSETS AND LIABILI_3

REGULATORY ASSETS AND LIABILITIES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Feb. 28, 2021
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Assets, Current	$ 1,611,676	$ 56,773
Regulatory Assets, Noncurrent	724,862	366,956
Regulatory Liability, Current	(8,090)	(15,761)
Regulatory Liability, Noncurrent	(552,928)	(547,563)
Net regulatory assets and liabilities, current	1,603,586	41,012
Net regulatory assets and liabilities, noncurrent	171,934	(180,607)
Net Regulatory Assets	1,775,520	(139,595)
February 2021 Natural Gas Purchases				$ 2,100,000
ONG Deferred Extraordinary Costs from 2021 Winter Storm Uri	1,300,000
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	52,400
KGS Deferred Extraordinary Costs from 2021 Winter Storm Uri	388,300
TGS Deferred Extraordinary Costs from 2021 Winter Storm Uri	256,600
Deferred Extraordinary Costs from 2021 Winter Storm Uri	2,000,000
Reduction in ADIT recorded as an EDIT regulatory liability associated with reduction of Oklahoma state income tax	29,300
Kansas Gas Service tax reform regulatory liability	84,200
Amortization of Rate Deferral	5,500	3,200	$ 2,500
North Texas Service Area [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
TGS Deferred Extraordinary Costs from 2021 Winter Storm Uri	59,500
Federal income tax rate changes [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Liability, Current	0	0
Regulatory Liability, Noncurrent	(552,928)	(547,563)
Regulatory Liabilities	$ (552,928)	$ (547,563)
Over-recovered purchased-gas costs [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Asset, Amortization Period	1 year	1 year
Regulatory Liability, Current	$ (8,090)	$ (15,761)
Regulatory Liability, Noncurrent	0	0
Regulatory Liabilities	(8,090)	(15,761)
Total regulated liabilities [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Liability, Current	(8,090)	(15,761)
Regulatory Liability, Noncurrent	(552,928)	(547,563)
Regulatory Liabilities	(561,018)	$ (563,324)
Winter weather event costs
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Assets, Current	1,536,054
Regulatory Assets, Noncurrent	428,023
Regulatory Assets	$ 1,964,077
Under-recovered purchased-gas costs [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Asset, Amortization Period	1 year	1 year
Regulatory Assets, Current	$ 31,863	$ 16,502
Regulatory Assets, Noncurrent	0	0
Regulatory Assets	31,863	16,502
Pension and postretirement benefit costs [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Assets, Current	11,507	16,541
Regulatory Assets, Noncurrent	260,559	341,266
Regulatory Assets	$ 272,066	$ 357,807
Reacquired debt costs [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Asset, Amortization Period	6 years	7 years
Regulatory Assets, Current	$ 812	$ 812
Regulatory Assets, Noncurrent	4,070	4,866
Regulatory Assets	$ 4,882	$ 5,678
MGP Costs [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Asset, Amortization Period	15 years	15 years
Regulatory Assets, Current	$ 98	$ 98
Regulatory Assets, Noncurrent	29,841	18,711
Regulatory Assets	$ 29,939	$ 18,809
Ad valorem tax [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Asset, Amortization Period	1 year	1 year
Regulatory Assets, Current	$ 8,561	$ 5,558
Regulatory Assets, Noncurrent	0	0
Regulatory Assets	$ 8,561	$ 5,558
Weather normalization [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Asset, Amortization Period	1 year	1 year
Regulatory Assets, Current	$ 10,044	$ 4,806
Regulatory Assets, Noncurrent	0	0
Regulatory Assets	$ 10,044	$ 4,806
Customer Credit Deferrals
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Asset, Amortization Period	1 year	1 year
Regulatory Assets, Current	$ 10,685	$ 10,267
Regulatory Assets, Noncurrent	0	0
Regulatory Assets	$ 10,685	$ 10,267
Other regulatory assets [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Asset, Amortization Period	1 to 18 years	1 to 18 years
Regulatory Assets, Current	$ 2,052	$ 2,189
Regulatory Assets, Noncurrent	2,369	2,113
Regulatory Assets	4,421	4,302
Total regulatory assets, net of amortization [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Assets, Current	1,611,676	56,773
Regulatory Assets, Noncurrent	724,862	366,956
Regulatory Assets	$ 2,336,538	$ 423,729

PROPERTY, PLANT AND EQUIPMENT_3

PROPERTY, PLANT AND EQUIPMENT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 7,274,268	$ 6,838,603
Accumulated depreciation and amortization	(2,083,433)	(1,971,546)
Net property, plant and equipment	$ 5,190,835	4,867,057
Minimum [Member]
Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	2.50%
Maximum [Member]
Property, Plant and Equipment [Line Items]
Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service	3.50%
Regulated [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 7,274,268	6,838,603
Accumulated depreciation and amortization	(2,083,433)	(1,971,546)
Net property, plant and equipment	5,190,835	4,867,057
Interest costs capitalized	4,200	4,200	$ 4,600
Construction work in process expenditures incurred but not yet paid	25,600	24,300	$ 20,900
Natural gas distribution pipelines and related equipment | Regulated [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	5,836,066	5,517,488
Natural gas transmission pipelines and related equipment | Regulated [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	624,528	586,360
General plant and other | Regulated [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	712,659	657,037
Construction work in process | Regulated [Member]
Property, Plant and Equipment [Line Items]
Property, plant and equipment	$ 101,015	$ 77,718

SHARE-BASED PAYMENTS (Details)

SHARE-BASED PAYMENTS (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Share-based Payments [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant	1,800,000
Share-based compensation expense, net of tax	$ 7,500	$ 7,000	$ 6,800
Share-based compensation, tax benefit	2,500	2,300	2,200
Fair value of shares granted (thousands of dollars)	$ 3,660	3,005	3,001
Common Stock, Capital Shares Reserved for Future Issuance	4,300,000
Restricted Stock Units (RSUs) [Member]
Share-based Payments [Line Items]
Award vesting period	3 years
Forfeiture rate maximum (in hundredths)	3.00%
Total compensation cost not yet recognized	$ 3,600
Total compensation cost not yet recognized, period for recognition	1 year 8 months 12 days
Fair value of vested shares	$ 3,400	$ 3,300	$ 3,300
Nonvested beginning balance (in units)	99,800
Nonvested beginning balance (in dollars per unit)	$ 82.29
Granted (in units)	50,353
Weighted -average grant date fair value (per unit)	$ 72.69	$ 96.21	$ 83.94
Vested (in units)	(42,821)
Vested (in dollars per unit)	$ 71.67
Forfeited (in units)	(13,058)
Forfeited (in dollars per unit)	$ 81.07
Nonvested ending balance (in units)	94,274	99,800
Nonvested ending balance (in dollars per unit)	$ 82.16	$ 82.29
Performance Unit Awards [Member]
Share-based Payments [Line Items]
Award vesting period	3 years
Forfeiture rate maximum (in hundredths)	3.00%
Description	Upon vesting, a holder of performance stock units is entitled to receive a number of shares of common stock equal to a percentage (0 percent to 200 percent) of the performance stock units granted, based on our total shareholder return over the vesting period, compared with the total shareholder return of a peer group of other utilities over the same period.
Total compensation cost not yet recognized	$ 6,600
Total compensation cost not yet recognized, period for recognition	1 year 8 months 12 days
Fair value of vested shares	$ 7,200	$ 10,200	$ 12,700
Nonvested beginning balance (in units)	208,520
Nonvested beginning balance (in dollars per unit)	$ 87.97
Granted (in units)	107,381
Weighted -average grant date fair value (per unit)	$ 82.51	$ 102.77	$ 89.86
Vested (in units)	(76,483)
Vested (in dollars per unit)	$ 74.04
Forfeited (in units)	(40,819)
Forfeited (in dollars per unit)	$ 89.19
Nonvested ending balance (in units)	198,599	208,520
Nonvested ending balance (in dollars per unit)	$ 90.13	$ 87.97
Fair value of shares granted (thousands of dollars)	$ 8,860	$ 6,502	$ 6,401
Expected volatility rate	32.70%	16.40%	18.70%
Expected dividend yield	3.19%	2.25%	2.38%
Risk-free interest rate	0.20%	1.40%	2.50%
Employee Stock Purchase Plan [Member]
Share-based Payments [Line Items]
Description	Subject to certain exclusions, all employees who work at least 20 hours per week are eligible to participate in the ESPP.  Employees can choose to have up to 10 percent of their annual base pay withheld to purchase our common stock, subject to terms and limitations of the plan. The purchase price of the stock is 85 percent of the lower of the average market price of our common stock on the grant date or exercise date.
Common Stock, Capital Shares Reserved for Future Issuance	1,250,000
Maximum allowable percentage of annual base pay withheld to purchase common stock	10.00%
Purchase price percentage of the lower of its grant date or exercise date market price (in hundredths)	85.00%
Percent of employees who participated in the Employee Stock Purchase Plan	44.00%	50.00%	44.00%
Shares sold under employee stock purchase plan	89,240	92,507	71,613
Share price of shares sold under Employee Stock Purchase Plan in dollars per share	$ 63.41	$ 64.77	$ 71.42
Share-based Payment Arrangement, Expense	$ 1,100	$ 1,100	$ 1,500

EMPLOYEE BENEFIT PLANS (Details

EMPLOYEE BENEFIT PLANS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plans and Other Postemployment Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan Assumptions Used To Determine Benefit Obligations Rate of Compensation Increase, Minimum	3.10%	3.10%
Defined Benefit Plan Assumptions Used To Determine Benefit Obligations Rate of Compensation Increase, Maximum	5.00%	3.90%
Compensation increase rate - minimum	3.10%	3.10%	3.20%
Compensation increase rate- maximum	3.90%	4.00%	4.00%
Description of basis used to determine overall expected long-term rate of return on plan assets	We determine our discount rates annually. We estimate our discount rate based upon a comparison of the expected cash flows associated with our future payments under our defined benefit pension and other postemployment obligations to a hypothetical bond portfolio created using high-quality bonds that closely match expected cash flows. Bond portfolios are developed by selecting a bond for each of the next 60 years based on the maturity dates of the bonds. Bonds selected to be included in the portfolios are only those rated by Moody’s as AA- or better and exclude callable bonds, bonds with less than a minimum issue size, yield outliers and other filtering criteria to remove unsuitable bonds.
Regulatory Assets, Noncurrent	$ 724,862,000	$ 366,956,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Liability, Defined Benefit Plan, Noncurrent	(35,226,000)	(97,637,000)
Lump Sum benefit payments paid		12,500,000
Amortization of unrecognized prior service cost	(279,000)	(117,000)	$ (673,000)
Defined Benefit Plan, Amortization of Gain (Loss)	45,896,000	42,492,000	35,283,000
Total recognized in other comprehensive income (loss)	1,250,000	$ (1,038,000)	$ (1,435,000)
Amount recognized in other comprehensive income	$ 0
Health care cost-trend rate assumed for next year	6.00%	6.25%
Rate to which the cost-trend rate is assumed to decline (the ultimate trend rate)	4.50%	4.50%
Year that the rate reaches the ultimate trend rate	2028	2026
Target asset allocation	100.00%
Grosvenor Registered Multi Limited Partnership
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	$ 42,632,000
Fair value of plan assets, end of period	44,818,000	$ 42,632,000
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 0	$ 0
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Frequency	quarterly	quarterly
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Description	65	65
K2 Institutional Investors II Limited Partnership
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	$ 45,002,000
Fair value of plan assets, end of period	46,638,000	$ 45,002,000
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Unfunded Commitments	$ 0	$ 0
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Frequency	quarterly	quarterly
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share, Investment Redemption, Description	91	91
Investment-grade bonds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Target asset allocation	60.00%
US Large-Cap Equity [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Target asset allocation	14.00%
Alternative investments [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Target asset allocation	10.00%
Developed foreign large-cap equities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Target asset allocation	7.00%
Mid-cap equities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Target asset allocation	5.00%
Emerging market equities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Target asset allocation	1.00%
Small-cap equities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Target asset allocation	3.00%
Fixed Income Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	65 percent
Equity Securities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Defined Benefit Plan, Plan Assets, Investment Policy and Strategy, Description	35 percent
Pension Plan [Member]
Defined Benefit Plans and Other Postemployment Benefit Plans Table Text Block [Line Items]
Discount rate	3.05%	2.80%
Weighted average discount rate	2.80%	3.50%	4.40%
Expected long-term return on plan assets	7.15%	7.20%	7.20%
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant	$ 0	$ 0
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of period	1,077,641,000	1,001,368,000
Service cost	13,811,000	12,869,000	$ 12,030,000
Interest cost	29,458,000	34,179,000	40,670,000
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant	0	0
Actuarial loss (gain)	(19,587,000)	91,566,000
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(51,333,000)	(62,341,000)
Benefit obligation, end of period	1,049,990,000	1,077,641,000	1,001,368,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	987,583,000	907,974,000
Actual return on plan assets	75,999,000	140,939,000
Employer contributions	995,000	1,011,000
Benefits paid	(51,333,000)	(62,341,000)
Settlements	0	0
Fair value of plan assets, end of period	1,013,244,000	987,583,000	907,974,000
Defined Benefit Plan, Funded (Unfunded) Status of Plan	(36,746,000)	(90,058,000)
Assets for Plan Benefits, Defined Benefit Plan	0	0
Liability, Defined Benefit Plan, Current	(1,521,000)	(1,056,000)
Liability, Defined Benefit Plan, Noncurrent	(35,225,000)	(89,002,000)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	(36,746,000)	(90,058,000)
Accumulated benefit obligation	1,000,000,000	1,000,000,000
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	1,500,000
Service cost	13,811,000	12,869,000	12,030,000
Interest cost	29,458,000	34,179,000	40,670,000
Expected return on assets	(62,382,000)	(61,119,000)	(61,939,000)
Amortization of unrecognized prior service cost	1,562,000	1,192,000	852,000
Defined Benefit Plan, Amortization of Gain (Loss)	45,523,000	42,319,000	33,039,000
Net periodic benefit cost	26,410,000	28,248,000	23,800,000
Net loss arising during the period	67,000	(2,519,000)	(2,766,000)
Deferred income taxes	(379,000)	289,000	479,000
Total recognized in other comprehensive income (loss)	1,250,000	(1,038,000)	(1,435,000)
Accumulated loss	(272,332,000)	(351,059,000)
Accumulated other comprehensive loss before regulatory assets	(272,332,000)	(351,059,000)
Regulatory asset for regulated entities	264,027,000	341,125,000
Accumulated other comprehensive loss after regulatory assets	(8,305,000)	(9,934,000)
Deferred income taxes	1,778,000	2,157,000
Accumulated other comprehensive loss, net of tax	(6,527,000)	(7,777,000)
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Level 3 fair value measurement, January 1	112,237,000	107,781,000
Net realized and unrealized gains (losses)		6,613,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Period Increase	1,625,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Period Decrease	(3,368,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	2,197,000	992,000
Settlements	(3,934,000)	(3,149,000)
Level 3 fair value measurement, December 31	108,757,000	112,237,000	107,781,000
2021	52,936,000
2022	53,745,000
2023	54,440,000
2024	55,075,000
2025	55,852,000
2026 through 2030	283,344,000
Pension Plan [Member] | Equity Securities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	428,093,000
Fair value of plan assets, end of period	223,871,000	428,093,000
Pension Plan [Member] | Government Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	78,080,000
Fair value of plan assets, end of period	205,741,000	78,080,000
Pension Plan [Member] | Corporate Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	343,118,000
Fair value of plan assets, end of period	440,445,000	343,118,000
Pension Plan [Member] | Cash and Money Market Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	24,900,000
Fair value of plan assets, end of period	34,410,000	24,900,000
Pension Plan [Member] | Insurance contracts and group annuity contracts [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	24,603,000
Fair value of plan assets, end of period	17,301,000	24,603,000
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Level 3 fair value measurement, January 1	24,603,000	25,988,000
Net realized and unrealized gains (losses)		1,764,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Period Increase	0
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Period Decrease	(3,368,000)
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	0	0
Settlements	(3,934,000)	(3,149,000)
Level 3 fair value measurement, December 31	17,301,000	24,603,000	25,988,000
Pension Plan [Member] | Other Investments [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	88,789,000
Fair value of plan assets, end of period	91,476,000	88,789,000
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Level 3 fair value measurement, January 1	87,634,000	81,793,000
Net realized and unrealized gains (losses)		4,849,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Period Increase	1,625,000
Fair Value Measurement With Unobservable Inputs Reconciliation Recurring Basis Asset Period Decrease	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset, Purchases	2,197,000	992,000
Settlements	0	0
Level 3 fair value measurement, December 31	91,456,000	87,634,000	$ 81,793,000
Pension Plan [Member] | Level 1 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	394,228,000
Fair value of plan assets, end of period	227,735,000	394,228,000
Pension Plan [Member] | Level 1 [Member] | Equity Securities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	392,639,000
Fair value of plan assets, end of period	223,871,000	392,639,000
Pension Plan [Member] | Level 1 [Member] | Government Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Pension Plan [Member] | Level 1 [Member] | Corporate Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Pension Plan [Member] | Level 1 [Member] | Cash and Money Market Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	1,589,000
Fair value of plan assets, end of period	3,864,000	1,589,000
Pension Plan [Member] | Level 1 [Member] | Insurance contracts and group annuity contracts [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Pension Plan [Member] | Level 1 [Member] | Other Investments [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Pension Plan [Member] | Level 2 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	481,118,000
Fair value of plan assets, end of period	676,752,000	481,118,000
Pension Plan [Member] | Level 2 [Member] | Equity Securities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	35,454,000
Fair value of plan assets, end of period	0	35,454,000
Pension Plan [Member] | Level 2 [Member] | Government Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	78,080,000
Fair value of plan assets, end of period	205,741,000	78,080,000
Pension Plan [Member] | Level 2 [Member] | Corporate Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	343,118,000
Fair value of plan assets, end of period	440,445,000	343,118,000
Pension Plan [Member] | Level 2 [Member] | Cash and Money Market Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	23,311,000
Fair value of plan assets, end of period	30,546,000	23,311,000
Pension Plan [Member] | Level 2 [Member] | Insurance contracts and group annuity contracts [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Pension Plan [Member] | Level 2 [Member] | Other Investments [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	1,155,000
Fair value of plan assets, end of period	20,000	1,155,000
Pension Plan [Member] | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	112,237,000
Fair value of plan assets, end of period	108,757,000	112,237,000
Pension Plan [Member] | Level 3 [Member] | Equity Securities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Pension Plan [Member] | Level 3 [Member] | Government Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Pension Plan [Member] | Level 3 [Member] | Corporate Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Pension Plan [Member] | Level 3 [Member] | Cash and Money Market Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Pension Plan [Member] | Level 3 [Member] | Insurance contracts and group annuity contracts [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	24,603,000
Fair value of plan assets, end of period		24,603,000
Pension Plan [Member] | Level 3 [Member] | Other Investments [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	$ 87,634,000
Fair value of plan assets, end of period		$ 87,634,000
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postemployment Benefit Plans Table Text Block [Line Items]
Minimum number of years of service for certain employees to be eligible to participate in shared welfare plans that provide postemployment medical and life insurance benefits	five years
Discount rate	3.00%	2.70%
Weighted average discount rate	2.70%	3.40%	4.40%
Expected long-term return on plan assets	7.50%	7.65%	7.35%
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant	$ 3,226,000	$ 3,500,000
Defined Benefit Plan, Change in Benefit Obligation [Roll Forward]
Benefit obligation, beginning of period	239,530,000	230,490,000
Service cost	1,587,000	1,692,000	$ 1,734,000
Interest cost	6,251,000	7,557,000	9,318,000
Defined Benefit Plan, Benefit Obligation, Contributions by Plan Participant	3,226,000	3,500,000
Actuarial loss (gain)	(8,894,000)	14,013,000
Defined Benefit Plan, Benefit Obligation, Benefits Paid	(18,894,000)	(17,722,000)
Benefit obligation, end of period	222,806,000	239,530,000	230,490,000
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	230,895,000	207,182,000
Actual return on plan assets	14,786,000	35,837,000
Employer contributions	1,981,000	2,098,000
Benefits paid	(18,894,000)	(17,722,000)
Settlements	0	0
Fair value of plan assets, end of period	231,994,000	230,895,000	207,182,000
Defined Benefit Plan, Funded (Unfunded) Status of Plan	9,188,000	(8,635,000)
Assets for Plan Benefits, Defined Benefit Plan	9,188,000	0
Liability, Defined Benefit Plan, Current	0	0
Liability, Defined Benefit Plan, Noncurrent	0	(8,635,000)
Defined Benefit Plan, Amounts for Asset (Liability) Recognized in Statement of Financial Position	9,188,000	(8,635,000)
Defined Benefit Plan, Expected Future Employer Contributions, Next Fiscal Year	0
Service cost	1,587,000	1,692,000	1,734,000
Interest cost	6,251,000	7,557,000	9,318,000
Expected return on assets	(16,807,000)	(15,469,000)	(12,586,000)
Amortization of unrecognized prior service cost	(279,000)	(117,000)	(673,000)
Defined Benefit Plan, Amortization of Gain (Loss)	373,000	173,000	2,244,000
Net periodic benefit cost	(8,875,000)	(6,164,000)	37,000
Prior service credit (cost)	(194,000)	85,000
Accumulated loss	(5,887,000)	(13,134,000)
Accumulated other comprehensive loss before regulatory assets	(6,081,000)	(13,049,000)
Regulatory asset for regulated entities	6,081,000	13,049,000
Accumulated other comprehensive loss after regulatory assets	0	0
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
2021	15,744,000
2022	15,571,000
2023	15,184,000
2024	14,940,000
2025	14,580,000
2026 through 2030	67,566,000
Other Postretirement Benefits Plan [Member] | Equity Securities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	73,578,000
Fair value of plan assets, end of period	25,577,000	73,578,000
Other Postretirement Benefits Plan [Member] | Government Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	41,366,000	0
Other Postretirement Benefits Plan [Member] | Corporate Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	39,115,000
Fair value of plan assets, end of period	41,601,000	39,115,000
Other Postretirement Benefits Plan [Member] | Cash and Money Market Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	8,123,000
Fair value of plan assets, end of period	13,532,000	8,123,000
Other Postretirement Benefits Plan [Member] | Insurance contracts and group annuity contracts [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	110,079,000
Fair value of plan assets, end of period	109,918,000	110,079,000
Other Postretirement Benefits Plan [Member] | Level 1 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	73,630,000
Fair value of plan assets, end of period	26,119,000	73,630,000
Other Postretirement Benefits Plan [Member] | Level 1 [Member] | Equity Securities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	73,578,000
Fair value of plan assets, end of period	25,577,000	73,578,000
Other Postretirement Benefits Plan [Member] | Level 1 [Member] | Government Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Other Postretirement Benefits Plan [Member] | Level 1 [Member] | Corporate Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Other Postretirement Benefits Plan [Member] | Level 1 [Member] | Cash and Money Market Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	52,000
Fair value of plan assets, end of period	542,000	52,000
Other Postretirement Benefits Plan [Member] | Level 1 [Member] | Insurance contracts and group annuity contracts [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Other Postretirement Benefits Plan [Member] | Level 2 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	157,265,000
Fair value of plan assets, end of period	205,875,000	157,265,000
Other Postretirement Benefits Plan [Member] | Level 2 [Member] | Equity Securities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Other Postretirement Benefits Plan [Member] | Level 2 [Member] | Government Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	41,366,000	0
Other Postretirement Benefits Plan [Member] | Level 2 [Member] | Corporate Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	39,115,000
Fair value of plan assets, end of period	41,601,000	39,115,000
Other Postretirement Benefits Plan [Member] | Level 2 [Member] | Cash and Money Market Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	8,071,000
Fair value of plan assets, end of period	12,990,000	8,071,000
Other Postretirement Benefits Plan [Member] | Level 2 [Member] | Insurance contracts and group annuity contracts [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	110,079,000
Fair value of plan assets, end of period	109,918,000	110,079,000
Other Postretirement Benefits Plan [Member] | Level 3 [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Other Postretirement Benefits Plan [Member] | Level 3 [Member] | Equity Securities [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Other Postretirement Benefits Plan [Member] | Level 3 [Member] | Government Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Other Postretirement Benefits Plan [Member] | Level 3 [Member] | Corporate Obligations [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Other Postretirement Benefits Plan [Member] | Level 3 [Member] | Cash and Money Market Funds [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	0	0
Other Postretirement Benefits Plan [Member] | Level 3 [Member] | Insurance contracts and group annuity contracts [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward]
Fair value of plan assets, beginning of period	0
Fair value of plan assets, end of period	$ 0	0
ONE Gas 401(k) Plan [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Percent of employee contributions matched of eligible compensation (in hundredths)	100.00%
Maximum percentage of each participants eligible compensation subject to certain limits matching (in hundredths)	6.00%
Contributions made to 401(k) plan	$ 14,300,000	13,800,000	12,800,000
ONE Gas Profit-Sharing Plan [Member]
Defined Benefit Plan, Change in Fair Value of Plan Assets, Level 3 Reconciliation [Roll Forward]
Profit sharing contribution percentage	1.00%
Contributions made to profit-sharing plan	$ 9,900,000	9,400,000	$ 8,500,000
Non-service Costs [Member]
Defined Benefit Plans and Other Postemployment Benefit Plans Table Text Block [Line Items]
Regulatory Assets, Noncurrent	$ 6,100,000	$ 6,000,000

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Current income tax provision (benefit)
Federal	$ (1,568)	$ 20,129	$ 24,537
State	(1,565)	2,965	5,008
Total current income tax provision (benefit)	(3,133)	23,094	29,545
Deferred income tax provision
Federal	37,810	10,757	8,375
State	5,639	7,728	4,932
Total deferred income tax provision	43,449	18,485	13,307
Income Tax Reconciliation [Abstract]
Income before income taxes	$ 246,750	$ 237,991	$ 229,601
Federal Statutory Income Tax Rate	21.00%	21.00%	21.00%
Provision for federal income taxes	$ 51,817	$ 49,978	$ 48,215
State income taxes, net of federal benefit	4,074	10,693	9,758
Amortization of EDIT regulatory liability	(17,289)	(17,031)	(12,828)
Effective Income Tax Rate Reconciliation, tax benefit of employee share based compensation	(469)	(1,489)	(2,116)
Other, net	2,183	(572)	(177)
Income tax provision	40,316	41,579	$ 42,852
Deferred tax assets
Deferred tax assets, employee benefits and other accrued liabilities	11,126	28,127
Deferred tax asset, regulatory adjustments	120,051	121,738
Net operating loss	424,861	0
Deferred Tax Assets, Leasing Arrangements	6,906	9,319
Other	12,597	4,790
Total deferred tax assets	575,541	163,974
Deferred tax liabilities
Excess of tax over book depreciation	734,051	717,492
Purchased-gas cost adjustment - winter weather event	421,070	0
Purchased-gas cost adjustment - other	37,433	5,240
Other regulatory assets and liabilities, net	71,541	88,260
Deferred Tax Liabilities, Leasing Arrangements	6,730	9,788
Total deferred tax liabilities	1,270,825	820,780
Net deferred tax liabilities	695,284	$ 656,806
Reduction in ADIT recorded as an EDIT regulatory liability associated with reduction of Oklahoma state income tax	29,300
Kansas Gas Service tax reform regulatory liability	84,200
Reduction to base rates due to Kansas Gas Service tax reform regulatory liability	4,900
Deferred Tax Liabilities, Regulatory Assets and Liabilities - Winter Storm Uri	421,100
Domestic Tax Authority
Deferred tax assets
Net operating loss	386,000
State and Local Jurisdiction
Deferred tax assets
Net operating loss	$ 38,900

OTHER INCOME AND EXPENSE (Detai

OTHER INCOME AND EXPENSE (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Net periodic cost other than service cost	$ (3,930)	$ (5,071)	$ (5,895)
Earnings (losses) on investments associated with nonqualified employee benefit plans	3,699	4,616	5,268
Other, net	(2,976)	(2,565)	(2,349)
Other expense, net	$ (3,207)	$ (3,020)	$ (2,976)

COMMITMENTS AND CONTINGENCIES -

COMMITMENTS AND CONTINGENCIES - (Details) - MGP Costs [Member] $ in Millions	12 Months Ended
	Dec. 31, 2021USD ($)	Dec. 31, 2020USD ($)
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
Regulatory Asset for Costs Associated with Manufactured Gas Sites	$ 29.9	$ 18.8
Number of sites with ongoing groundwater monitoring	7
Accrual for Environmental Loss Contingencies, Revision in Estimates	$ 11.2
Accrual for Environmental Loss Contingencies	$ 22.8	$ 14.5