ONE Gas (OGS) 10-Q 29 Oct 15 2015 Q3 Quarterly report Financial data

Document And Entity Information

Document And Entity Information - shares	9 Months Ended
	Sep. 30, 2015	Oct. 20, 2015
Document Information [Line Items]
Entity Registrant Name	ONE Gas, Inc.
Entity Central Index Key	1,587,732
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		52,154,655
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2015

STATEMENTS OF INCOME

STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Gross Margin
Revenues	$ 225,226	$ 241,522	$ 1,158,543	$ 1,304,538
Cost of natural gas	54,724	75,070	548,226	701,757
Net margin	170,502	166,452	610,317	602,781
Operating expenses
Operations and maintenance	98,698	101,829	304,681	309,154
Depreciation and amortization	33,956	31,217	98,592	93,995
General taxes	12,897	14,287	41,818	44,348
Total operating expenses	145,551	147,333	445,091	447,497
Operating income	24,951	19,119	165,226	155,284
Other income	166	8	1,051	1,005
Other expense	(1,884)	(652)	(2,840)	(1,829)
Interest expense, net	(11,233)	(11,160)	(33,592)	(35,886)
Income before income taxes	12,000	7,315	129,845	118,574
Income taxes	(4,629)	(2,662)	(50,017)	(45,391)
Net income	$ 7,371	$ 4,653	$ 79,828	$ 73,183
Earnings per share
Basic	$ 0.14	$ 0.09	$ 1.52	$ 1.40
Diluted	$ 0.14	$ 0.09	$ 1.50	$ 1.38
Average shares (thousands)
Basic	52,408	52,361	52,627	52,353
Diluted	53,072	53,014	53,315	52,848
Dividends declared per share of stock	$ 0.30	$ 0.28	$ 0.90	$ 0.56

STATEMENTS OF COMPREHENSIVE INC

STATEMENTS OF COMPREHENSIVE INCOME STATEMENTS OF COMPREHENSIVE INCOME Parenthetical - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
STATEMENTS OF COMPREHENSIVE INCOME Parenthetical [Abstract]
Pension and other postretirement benefit plans, tax	$ (88)	$ 49	$ (264)	$ 98

STATEMENTS OF COMPREHENSIVE IN4

STATEMENTS OF COMPREHENSIVE INCOME STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Net income	$ 7,371	$ 4,653	$ 79,828	$ 73,183
Other comprehensive income (loss), net of tax
Change in pension and postretirement benefit plan liability, net of tax of $(88), $49, $(264) and $98, respectively	141	(78)	423	(156)
Other comprehensive income (loss), net of tax	141	(78)	423	(156)
Comprehensive income	$ 7,512	$ 4,575	$ 80,251	$ 73,027

BALANCE SHEETS

BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
Property, plant and equipment
Property, plant and equipment	$ 5,040,313	$ 4,850,201
Accumulated depreciation and amortization	1,604,509	1,556,481
Net property, plant and equipment	3,435,804	3,293,720
Current assets
Cash and cash equivalents	52,974	11,943
Accounts receivable, net	103,406	326,749
Materials and supplies	33,400	27,511
Income tax receivable	23,725	43,800
Natural gas in storage	159,912	185,300
Regulatory assets	31,703	50,193
Other current assets	12,227	22,005
Total current assets	417,347	667,501
Goodwill and other assets
Regulatory assets	440,312	478,723
Goodwill	157,953	157,953
Other assets	54,905	51,313
Total goodwill and other assets	653,170	687,989
Total assets	4,506,321	4,649,210
Equity and long-term debt
Common stock, $0.01 par value: authorized 250,000,000 shares; issued 52,598,005 shares and outstanding 52,151,279 shares at September 30, 2015; issued and outstanding 52,083,859 at December 31, 2014	526	521
Paid-in Capital	1,762,508	1,758,796
Retained earnings	71,746	39,894
Accumulated other comprehensive income (loss)	(4,751)	(5,174)
Treasury stock	(19,108)	0
Total equity	1,810,921	1,794,037
Long-term debt, excluding current maturities	1,201,306	1,201,311
Total equity and long-term debt	3,012,227	2,995,348
Current liabilities
Current maturities of long-term debt	7	6
Notes payable	0	42,000
Accounts payable	57,240	159,064
Accrued interest	7,647	18,872
Accrued taxes other than income	40,429	44,742
Accrued liabilities	18,000	26,019
Customer deposits	58,331	60,003
Regulatory liabilities	41,337	32,467
Other current liabilities	10,478	9,260
Total current liabilities	233,469	392,433
Deferred credits and other liabilities [Abstract]
Deferred income taxes	907,647	894,585
Employee benefit obligations	274,073	287,779
Other deferred credits	78,905	79,065
Total deferred credits and other liabilities	$ 1,260,625	$ 1,261,429
Commitments and contingencies
Total liabilities and equity	$ 4,506,321	$ 4,649,210

BALANCE SHEETS BALANCE SHEETS P

BALANCE SHEETS BALANCE SHEETS Parenthetical - $ / shares	Sep. 30, 2015	Dec. 31, 2014
Common stock, par value per share	$ 0.01	$ 0.01
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	52,598,005	52,083,859
Common stock, shares outstanding	52,151,279	52,083,859
Treasury Stock, Shares	446,726	0

STATEMENTS OF CASH FLOWS

STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Operating activities
Net income	$ 79,828	$ 73,183
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	98,592	93,995
Deferred income taxes	19,384	2,828
Share-based compensation expense	3,863	5,651
Provision for doubtful accounts	2,951	5,019
Changes in assets and liabilities:
Accounts receivable	220,392	216,219
Materials and supplies	(5,889)	6,238
Income tax receivable	20,075	(4,862)
Natural gas in storage	25,388	(51,192)
Asset removal costs	(33,744)	(34,963)
Accounts payable	(104,948)	(70,063)
Accrued interest	(11,225)	7,521
Accrued taxes other than income	(4,313)	11,060
Accrued liabilities	(8,019)	15,977
Customer deposits	(1,672)	(43)
Regulatory assets and liabilities	64,368	23,308
Other assets and liabilities	(15,493)	(49,868)
Cash provided by operating activities	349,538	250,008
Investing activities
Capital expenditures	(199,678)	(224,619)
Cash used in investing activities	(199,678)	(224,619)
Financing activities
Repayments on notes payable, net	(42,000)	0
Repurchase of common stock	(24,122)	0
Issuance of debt, net of discounts	0	1,199,994
Long-term debt financing costs	0	(11,078)
Cash Payment to ONEOK Upon Separation	0	(1,130,000)
Issuance of common stock	4,471	1,330
Dividends paid	(47,178)	(29,121)
Cash provided by (used in) financing activities	(108,829)	31,125
Change in cash and cash equivalents	41,031	56,514
Cash and cash equivalents at beginning of period	11,943	3,171
Cash and cash equivalents at end of period	$ 52,974	$ 59,685

STATEMENT OF CHANGES IN EQUITY

STATEMENT OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Paid-in Capital [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Accumulated Other Comprehensive Income (Loss) [Member]
Treasury stock	$ 0				$ 0
Net income	79,828	$ 0	$ 0	$ 79,828	0	$ 0
Other comprehensive income	423	0	0	0		423
Treasury Stock, Value, Acquired, Cost Method	(24,122)	$ 0	0	0	(24,122)	0
Common stock issued, shares		514,146
Common stock issued, value	$ 7,933	$ 5	2,914	0	5,014	0
Common Stock Issued (in shares), beginning balance at Dec. 31, 2014	52,083,859	52,083,859
Common Stock Issued, beginning balance at Dec. 31, 2014	$ 521	$ 521
Paid-in Capital, beginning balance at Dec. 31, 2014	1,758,796
Retained earnings, beginning balance at Dec. 31, 2014	39,894			39,894
Accumulated Other Comprehensive Income (Loss), beginning balance at Dec. 31, 2014	(5,174)		1,758,796			(5,174)
Total equity, beginning balance at Dec. 31, 2014	$ 1,794,037
Common Stock Issued (in share), ending balance at Sep. 30, 2015	52,598,005	52,598,005
Common Stock Issued, ending balance at Sep. 30, 2015	$ 526	$ 526
Paid-in Capital, ending balance at Sep. 30, 2015	1,762,508
Retained earnings, ending balance at Sep. 30, 2015	71,746			71,746
Accumulated Other Comprehensive Income (Loss), ending balance at Sep. 30, 2015	(4,751)		1,762,508			(4,751)
Common stock dividends - $0.90 per share	(47,178)	$ 0	$ 798	$ (47,976)	0	$ 0
Total equity, ending balance at Sep. 30, 2015	1,810,921
Treasury stock	$ (19,108)				$ (19,108)

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Notes)	9 Months Ended
	Sep. 30, 2015
Significant Accounting Policies [Line Items]
SIGNIFICANT ACCOUNTING POLICIES	1. SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Our accompanying unaudited financial statements have been prepared pursuant to the rules and regulations of the SEC. These statements also have been prepared in accordance with GAAP and reflect all adjustments that, in our opinion, are necessary for a fair statement of the results for the interim periods presented. All such adjustments are of a normal recurring nature. The 2014 year-end balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. These unaudited financial statements should be read in conjunction with the audited financial statements and footnotes in our Annual Report. Due to the seasonal nature of our business, the results of operations for the three and nine months ended September 30, 2015 , are not necessarily indicative of the results that may be expected for a 12-month period. Separation - Prior to January 31, 2014, ONE Gas, Inc. was a wholly owned subsidiary of ONEOK and comprised its former natural gas distribution business. On January 31, 2014, we became an independent, publicly traded company as a result of a distribution by ONEOK of our common stock to ONEOK’s shareholders. Our common stock began trading “regular-way” under the ticker symbol “OGS” on the NYSE on February 3, 2014. We provide natural gas distribution services to more than 2 million customers in Oklahoma, Kansas and Texas through Oklahoma Natural Gas, Kansas Gas Service and Texas Gas Service, respectively. We serve residential, commercial, industrial and transportation customers in all three states. In addition, we also provide natural gas distribution services to wholesale and public authority customers. Basis of Presentation - Prior to our separation from ONEOK, our financial statements were derived from ONEOK’s financial statements, which included its natural gas distribution business as if we, for accounting purposes, had been a separate company for all periods presented. The financial statements for periods prior to the separation also include expense allocations for certain corporate functions historically performed by ONEOK, including allocations of general corporate expenses related to executive oversight, accounting, treasury, tax, legal, information technology and other services. We believe our assumptions underlying the financial statements, including the assumptions regarding the allocation of general corporate expenses from ONEOK, are reasonable. However, the financial statements may not include all of the actual expenses that would have been incurred by us and may not reflect our results of operations, financial position and cash flows had we been a separate publicly traded company during the periods presented prior to the separation. All financial information presented after the separation represents the results of operations, financial position and cash flows of ONE Gas. Accordingly: • Our Statements of Income and Comprehensive Income for the three and nine months ended September 30, 2014 , consist of the results of ONE Gas for the three and eight months ended September 30, 2014 , and the results of ONE Gas Predecessor for the one month ended January 31, 2014. • Our Statement of Cash Flows for the nine months ended September 30, 2014 , consists of the results of ONE Gas for the eight months ended September 30, 2014 , and the results of ONE Gas Predecessor for the one month ended January 31, 2014. Use of Estimates - The preparation of our 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 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, provision for doubtful accounts, 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 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. Related-Party Transactions - Prior to our separation from ONEOK on January 31, 2014, we had certain transactions with ONEOK, including, but not limited to, natural gas supply, allocated corporate services, employee benefits, cash management, derivatives and long-term lines of credit. Following the separation, any services we receive from ONEOK are now third-party transactions. The remaining related-party transactions are not material. Segments - We operate in one reportable business segment: regulated public utilities that deliver natural gas to residential, commercial, industrial, wholesale, public authority and transportation customers. The accounting policies for our segment are the same as described in Note 1 of our Notes to Financial Statements in our Annual Report. We evaluate our financial performance principally on operating income. For the three and nine months ended September 30, 2015 , and 2014 , we had no single external customer from which we received 10 percent or more of our gross revenues. Goodwill Impairment Test - We assess our goodwill for impairment at least annually as of July 1. At July 1, 2015, we assessed qualitative factors to determine whether it was more likely than not that the fair value of our reporting unit was less than its carrying amount. After assessing qualitative factors (including macroeconomic conditions, industry and market considerations, cost factors and overall financial performance), we determined that no further testing was necessary. Recently Issued Accounting Standards Update - In August 2015, the FASB issued ASU 2015-15, “Interest-Imputation of Interest (Subtopic 835-30),” which specifically addresses the presentation and subsequent measurement of debt issuance costs associated with line of credit arrangements. We do not expect this issued guidance, which will be adopted concurrently with ASU 2015-03, to have a material impact on our financial statements. In April 2015, the FASB issued ASU 2015-03, “Interest-Imputation of Interest,” which requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability. We do not expect this issued guidance, which is required to be adopted for our interim and annual reports for periods beginning after December 15, 2015, to have a material impact on our financial statements. In April 2015, the FASB issued ASU 2015-05, “Intangibles-Goodwill and Other-Internal-Use Software,” which helps entities evaluate the accounting for fees paid by a customer in a cloud computing arrangement. We are evaluating the impact of this issued guidance, which is required to be adopted for our interim and annual reports for periods beginning after December 15, 2015. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers,” which clarifies and converges the revenue recognition principles under GAAP and International Financial Reporting Standards. In July 2015, FASB delayed the effective date for one year. We are evaluating the impact of this issued guidance, which is required to be adopted for our interim and annual reports beginning with the first quarter 2018.

REGULATORY ASSETS AND LIABILITI

REGULATORY ASSETS AND LIABILITIES (Notes)	9 Months Ended
	Sep. 30, 2015
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Schedule of Regulatory Assets and Liabilities	2. REGULATORY ASSETS AND LIABILITIES The tables below present a summary of regulatory assets, net of amortization, and liabilities for the periods indicated: September 30, 2015 Current Noncurrent Total ( Thousands of dollars ) Under-recovered purchased-gas costs $ 10,354 $ — $ 10,354 Pension and postretirement benefit costs (see Note 8) 19,445 429,346 448,791 Reacquired debt costs 812 9,122 9,934 Other 1,092 1,844 2,936 Total regulatory assets, net of amortization 31,703 440,312 472,015 Accumulated removal costs (a) — (11,846 ) (11,846 ) Weather normalization (5,821 ) — (5,821 ) Over-recovered purchased-gas costs (33,363 ) — (33,363 ) Ad valorem tax (2,153 ) — (2,153 ) Total regulatory liabilities (41,337 ) (11,846 ) (53,183 ) Net regulatory assets (liabilities) $ (9,634 ) $ 428,466 $ 418,832 (a) Included in other deferred credits in our Balance Sheets. December 31, 2014 Current Noncurrent Total ( Thousands of dollars ) Under-recovered purchased-gas costs $ 28,712 $ — $ 28,712 Pension and postretirement benefit costs 18,108 466,684 484,792 Reacquired debt costs 812 9,730 10,542 Other 2,561 2,309 4,870 Total regulatory assets, net of amortization 50,193 478,723 528,916 Accumulated removal costs (a) — (15,451 ) (15,451 ) Weather normalization (16,516 ) — (16,516 ) Over-recovered purchased-gas costs (13,055 ) — (13,055 ) Ad valorem tax (2,896 ) — (2,896 ) Total regulatory liabilities (32,467 ) (15,451 ) (47,918 ) Net regulatory assets (liabilities) $ 17,726 $ 463,272 $ 480,998 (a) Included in other deferred credits in our Balance Sheets. Regulatory assets on our Balance Sheets, as authorized by various regulatory authorities, are probable of recovery. Base rates are designed to provide a recovery of costs during the period 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. Purchased-gas costs include the costs that have been over- or under-recovered from customers through the purchased-gas cost adjustment mechanisms and also include natural gas utilized in our operations, premiums paid and any cash settlements received from our purchased natural gas call options.

CREDIT FACILITIES (Notes)

CREDIT FACILITIES (Notes)	9 Months Ended
	Sep. 30, 2015
Line of Credit Facility [Line Items]
Short-term Debt [Text Block]	3. CREDIT FACILITY AND SHORT-TERM NOTES PAYABLE ONE Gas Credit Agreement - The ONE Gas Credit Agreement contains certain financial, operational and legal covenants. Among other things, these covenants include maintaining ONE Gas’ debt-to-capital ratio of no more than 70 percent at the end of any calendar quarter. The ONE Gas Credit Agreement also contains customary affirmative and negative covenants, including covenants relating to liens, indebtedness of subsidiaries, investments, changes in the nature of business, fundamental changes, transactions with affiliates, burdensome agreements and use of proceeds. In the event of a breach of certain covenants by ONE Gas, amounts outstanding under the ONE Gas Credit Agreement may become due and payable immediately. At September 30, 2015 , our debt-to-capital ratio was 40 percent and we were in compliance with all covenants under the ONE Gas Credit Agreement. The ONE Gas Credit Agreement includes a $50 million sublimit for the issuance of standby letters of credit and also features an option to request an increase in the size of the facility to an aggregate of $1.2 billion from $700 million upon satisfaction of customary conditions, including receipt of commitments from new lenders or increased commitments from existing lenders. Borrowings made under the facility are available for general corporate purposes. The ONE Gas Credit Agreement contains provisions for an applicable margin rate and an annual facility fee, both of which adjust with changes in our credit rating. Based on our current credit ratings, borrowings, if any, will accrue interest at LIBOR plus 79.5 basis points, and the annual facility fee is 8 basis points. We have a commercial paper program under which we may issue unsecured commercial paper up to a maximum amount of $700 million to fund short-term borrowing needs. 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 generally sold at par less a discount representing an interest factor. The ONE Gas Credit Agreement is available to repay the commercial paper notes, if necessary. Amounts outstanding under the commercial paper program reduce the borrowing capacity under the ONE Gas Credit Agreement. At September 30, 2015 , we had no short-term borrowings, $1.0 million in letters of credit issued under the ONE Gas Credit Agreement and $699.0 million of remaining credit available under the ONE Gas Credit Agreement.

LONG-TERM DEBT (Notes)

LONG-TERM DEBT (Notes)	9 Months Ended
	Sep. 30, 2015
Long-term Debt, Unclassified [Abstract]
Long-term Debt [Text Block]	4. LONG-TERM DEBT Senior Notes - We have senior notes, consisting of $300 million of 2.07 percent senior notes due in 2019 , $300 million of 3.61 percent senior notes due in 2024 and $600 million of 4.658 percent senior notes due in 2044 (collectively, our “Senior Notes”). The indenture governing our Senior Notes includes an event of default upon the acceleration of other indebtedness of $100 million or more. Such events of default would entitle the trustee or the holders of 25 percent in aggregate principal amount of the outstanding Senior Notes to declare those Senior Notes immediately due and payable in full.

EQUITY EQUITY (Notes)

EQUITY EQUITY (Notes)	9 Months Ended
	Sep. 30, 2015
EQUITY [Line Items]
EQUITY	5. EQUITY Dividends - In October 2015, a dividend of $0.30 per share ( $1.20 per share on an annualized basis) was declared for shareholders of record on November 13, 2015, payable December 1, 2015.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Notes)	9 Months Ended
	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Comprehensive Income (Loss) Note [Text Block]	6. ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) The following table sets forth the effect of reclassifications from accumulated other comprehensive income (loss) in our Statements of Income for the periods indicated: Three Months Ended Nine Months Ended Details about Accumulated Other Comprehensive September 30, September 30, Affected Line Item in the Income (Loss) Components 2015 2014 2015 2014 Statements of Income ( Thousands of dollars ) Pension and other postretirement benefit plan obligations (a) Amortization of net loss $ 12,564 $ 8,542 $ 37,694 $ 25,625 Amortization of unrecognized prior service cost (374 ) (303 ) (1,120 ) (909 ) 12,190 8,239 36,574 24,716 Regulatory adjustments (b) (11,961 ) (8,366 ) (35,887 ) (24,970 ) 229 (127 ) 687 (254 ) Income before income taxes (88 ) 49 (264 ) 98 Income tax expense Total reclassifications for the period $ 141 $ (78 ) $ 423 $ (156 ) Net income (a) These components of accumulated other comprehensive income (loss) are included in the computation of net periodic benefit cost. See Note 8 for additional detail of our net periodic benefit cost . (b) Regulatory adjustments represent pension and other postretirement benefit costs expected to be recovered through rates and are deferred as part of our regulatory assets. See Note 2 for additional disclosures of regulatory assets and liabilities.

EARNINGS PER SHARE (Notes)

EARNINGS PER SHARE (Notes)	9 Months Ended
	Sep. 30, 2015
EARNINGS PER SHARE [Line Items]
Earnings Per Share [Text Block]	7. 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 basic EPS, plus unvested stock awards granted under our compensation plans, but only to the extent these instruments dilute earnings per share. The following tables set forth the computation of basic and diluted EPS from continuing operations for the periods indicated: Three Months Ended September 30, 2015 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 7,371 52,408 $ 0.14 Diluted EPS Calculation Effect of dilutive securities — 664 Net income available for common stock and common stock equivalents $ 7,371 53,072 $ 0.14 Three Months Ended September 30, 2014 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 4,653 52,361 $ 0.09 Diluted EPS Calculation Effect of dilutive securities — 653 Net income available for common stock and common stock equivalents $ 4,653 53,014 $ 0.09 Nine Months Ended September 30, 2015 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 79,828 52,627 $ 1.52 Diluted EPS Calculation Effect of dilutive securities — 688 Net income available for common stock and common stock equivalents $ 79,828 53,315 $ 1.50 Nine Months Ended September 30, 2014 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 73,183 52,353 $ 1.40 Diluted EPS Calculation Effect of dilutive securities — 495 Net income available for common stock and common stock equivalents $ 73,183 52,848 $ 1.38 On January 31, 2014, 51,941,236 shares of our common stock were distributed to ONEOK shareholders in conjunction with the separation. For comparative purposes, and to provide a more meaningful calculation of weighted-average shares outstanding, we have assumed this amount and any shares associated with fully vested stock awards that have not been issued to be outstanding as of the beginning of each period prior to the separation presented in the calculation of weighted-average shares.

EMPLOYEE BENEFIT PLANS (Notes)

EMPLOYEE BENEFIT PLANS (Notes)	9 Months Ended
	Sep. 30, 2015
Employee Benefit Plans [Line Items]
EMPLOYEE BENEFIT PLANS	8. EMPLOYEE BENEFIT PLANS The following tables set forth the components of net periodic benefit cost for our pension and other postretirement benefit plans for the periods indicated: Pension Benefits Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 ( Thousands of dollars ) Components of net periodic benefit cost Service cost $ 3,497 $ 3,554 $ 10,518 $ 9,227 Interest cost 10,652 10,948 31,956 32,844 Expected return on assets (15,363 ) (14,965 ) (46,087 ) (44,895 ) Amortization of unrecognized prior service cost 66 137 200 411 Amortization of net loss 11,054 7,550 33,164 22,649 Net periodic benefit cost $ 9,906 $ 7,224 $ 29,751 $ 20,236 Other Postretirement Benefits Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 ( Thousands of dollars ) Components of net periodic benefit cost Service cost $ 849 $ 867 $ 2,547 $ 2,908 Interest cost 2,665 2,901 7,997 8,703 Expected return on assets (2,908 ) (2,848 ) (8,724 ) (8,544 ) Amortization of unrecognized prior service cost (440 ) (440 ) (1,320 ) (1,320 ) Amortization of net loss 1,510 992 4,530 2,976 Net periodic benefit cost $ 1,676 $ 1,472 $ 5,030 $ 4,723 We recover qualified pension benefit plan and other postretirement benefit plan costs through rates charged to our customers. Certain utility commissions require that the recovery of these costs be based on specific guidelines. The difference between these regulatory-based amounts and the periodic benefit cost calculated pursuant to GAAP is deferred as a regulatory asset or liability and amortized to expense over periods in which this difference will be recovered in rates, as authorized by the applicable utility commission. Measurement - In October 2015, plan amendments were approved to merge our frozen cash-balance defined benefit pension plan covering certain Texas Gas Service employees with our defined benefit pension plan covering nonbargaining unit employees and certain bargaining unit employees. In addition, we announced to certain pre-65 participants in our postretirement medical plans a change from a self-insured postretirement medical plan to a plan providing participants an annual benefit that will allow them to select coverage on a healthcare exchange. As a result, we will remeasure the respective plan assets and benefit obligations in the fourth quarter 2015.

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Notes)	9 Months Ended
	Sep. 30, 2015
Commitments and Contingencies [Line Items]
COMMITMENTS AND CONTINGENCIES	9. COMMITMENTS AND CONTINGENCIES Environmental Matters - We are subject to multiple historical, wildlife preservation and environmental laws and/or regulations 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, hazardous materials 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 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 Clean Air Act 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, results of operations and cash flows. We own or retain legal responsibility for the environmental conditions at 12 former manufactured natural gas sites in Kansas. These sites contain potentially harmful materials that are subject to control or remediation under various environmental laws and regulations. A consent agreement with the KDHE governs all work at these sites. The terms of the consent agreement allow 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. We have completed or addressed removal of the source of soil contamination at 11 of the 12 sites according to plans approved by the KDHE. Regulatory closure has been achieved at three of the sites. We have begun site assessment at the remaining site where no active remediation has occurred. 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 nine months ended September 30, 2015 and 2014 . We do not expect expenditures for these matters to have a material adverse affect on our financial condition, results of operations or cash flows. Pipeline Safety - We are subject to PHMSA regulations, including integrity-management regulations. PHMSA regulations require pipeline companies operating high-pressure transmission pipelines to perform integrity assessments on pipeline segments that pass through densely populated areas or near specifically designated high-consequence areas. In January 2012, the Pipeline Safety, Regulatory Certainty and Job Creation Act was signed into law. The law increased maximum penalties for violating federal pipeline safety regulations and directs the DOT and the Secretary of Transportation to conduct further review or studies on issues that may or may not be material to us. These issues include, but are not limited to, the following: • an evaluation of whether natural gas pipeline integrity-management requirements should be expanded beyond current high-consequence areas; • a verification of records for pipelines in class 3 and 4 locations and high-consequence areas to confirm maximum allowable operating pressures; and • a requirement to test previously untested pipelines operating above 30 percent yield strength in high-consequence areas. The potential capital and operating expenditures related to this legislation, the associated regulations or other new pipeline safety regulations are unknown. 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.

DERIVATIVE FINANCIAL INSTRUMENT

DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Notes)	9 Months Ended
	Sep. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair Value Disclosures	10. DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS Accounting Treatment - We record all derivative instruments at fair value, with the exception of normal purchases and normal sales that are expected to result in physical delivery. The accounting for changes in the fair value of a derivative instrument depends on whether it has been designated and qualifies as part of a hedging relationship and, if so, the reason for holding it, or if regulatory rulings require a different accounting treatment. If certain conditions are met, we may elect to designate a derivative instrument as a hedge to mitigate the risk of exposure to changes in fair values or cash flows. The table below summarizes the various ways in which we account for our derivative instruments and the impact on our financial statements: Recognition and Measurement Accounting Treatment Balance Sheet Income Statement Normal purchases and normal sales - Recorded at historical cost - Change in fair value not recognized in earnings Mark-to-market - Recorded at fair value - Change in fair value recognized in, and recoverable through, the purchased-gas cost adjustment mechanisms We have not elected to designate any of our derivative instruments as hedges. Premiums paid and any cash settlements received associated with the commodity derivative instruments entered into by us are included in, and recoverable through, the purchased-gas cost adjustment mechanisms. Determining Fair Value - 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 financial statements based on the observability of inputs used to estimate such fair value. The levels of the hierarchy are described below: • Level 1 - Unadjusted quoted prices in active markets for identical assets or liabilities; • Level 2 - Significant observable pricing inputs other than quoted prices included within Level 1 that are, either directly or indirectly, observable as of the reporting date. Essentially, this represents inputs that are derived principally from or corroborated by observable market data; and • Level 3 - May include one or more unobservable inputs that are significant in establishing a fair value estimate. These unobservable inputs are developed based on the best information available and may include our own internal data. We recognize transfers into and out of the levels as of the end of each reporting period. Determining the appropriate classification of our fair value measurements within the fair value hierarchy requires management’s judgment regarding the degree to which market data is observable or corroborated by observable market data. We categorize derivatives for which fair value is determined using multiple inputs within a single level, based on the lowest level input that is significant to the fair value measurement in its entirety. Derivative Instruments - At September 30, 2015 , we held purchased natural gas call options for the heating season ending March 2016, with total notional amounts of 38.1 Bcf, for which we paid premiums of $11.6 million , and had a fair value of $4.4 million . At December 31, 2014 , we held purchased natural gas call options for the heating season ended March 2015, with total notional amounts of 16.0 Bcf, for which we paid premiums of $6.4 million , and had a fair value of $0.1 million . The premiums paid and any cash settlements received are recorded as part of our unrecovered purchased-gas costs in current regulatory assets as these contracts are included in, and recoverable through, the purchased-gas cost adjustment mechanisms. Additionally, changes in fair value associated with these contracts are deferred as part of our unrecovered purchased-gas costs in our 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 NYMEX-settled prices. There were no transfers between levels for the three and nine months ended September 30, 2015 and 2014 . 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 bank deposits and money market accounts, and are classified as Level 1. 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 $1.2 billion at both September 30, 2015 and December 31, 2014. The estimated fair value of our long-term debt, including current maturities, was $1.2 billion and $1.3 billion at September 30, 2015 and December 31, 2014 , respectively. The estimated fair value of our Senior Notes at September 30, 2015 and December 31, 2014 , was determined using quoted market prices, and are considered Level 2.

SUMMARY OF SIGNIFICANT ACCOUN19

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2015
Significant Accounting Policies [Line Items]
Basis of Presentation	Basis of Presentation - Prior to our separation from ONEOK, our financial statements were derived from ONEOK’s financial statements, which included its natural gas distribution business as if we, for accounting purposes, had been a separate company for all periods presented. The financial statements for periods prior to the separation also include expense allocations for certain corporate functions historically performed by ONEOK, including allocations of general corporate expenses related to executive oversight, accounting, treasury, tax, legal, information technology and other services. We believe our assumptions underlying the financial statements, including the assumptions regarding the allocation of general corporate expenses from ONEOK, are reasonable. However, the financial statements may not include all of the actual expenses that would have been incurred by us and may not reflect our results of operations, financial position and cash flows had we been a separate publicly traded company during the periods presented prior to the separation. All financial information presented after the separation represents the results of operations, financial position and cash flows of ONE Gas. Accordingly: • Our Statements of Income and Comprehensive Income for the three and nine months ended September 30, 2014 , consist of the results of ONE Gas for the three and eight months ended September 30, 2014 , and the results of ONE Gas Predecessor for the one month ended January 31, 2014. • Our Statement of Cash Flows for the nine months ended September 30, 2014 , consists of the results of ONE Gas for the eight months ended September 30, 2014 , and the results of ONE Gas Predecessor for the one month ended January 31, 2014.
Use of Estimates	Use of Estimates - The preparation of our 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 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, provision for doubtful accounts, 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 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.
Related-Party Transactions	Related-Party Transactions - Prior to our separation from ONEOK on January 31, 2014, we had certain transactions with ONEOK, including, but not limited to, natural gas supply, allocated corporate services, employee benefits, cash management, derivatives and long-term lines of credit. Following the separation, any services we receive from ONEOK are now third-party transactions. The remaining related-party transactions are not material.
Segments	Segments - We operate in one reportable business segment: regulated public utilities that deliver natural gas to residential, commercial, industrial, wholesale, public authority and transportation customers. The accounting policies for our segment are the same as described in Note 1 of our Notes to Financial Statements in our Annual Report. We evaluate our financial performance principally on operating income. For the three and nine months ended September 30, 2015 , and 2014 , we had no single external customer from which we received 10 percent or more of our gross revenues.
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]	Goodwill Impairment Test - We assess our goodwill for impairment at least annually as of July 1. At July 1, 2015, we assessed qualitative factors to determine whether it was more likely than not that the fair value of our reporting unit was less than its carrying amount. After assessing qualitative factors (including macroeconomic conditions, industry and market considerations, cost factors and overall financial performance), we determined that no further testing was necessary.
Recently Issued Accounting Standards Update	Recently Issued Accounting Standards Update - In August 2015, the FASB issued ASU 2015-15, “Interest-Imputation of Interest (Subtopic 835-30),” which specifically addresses the presentation and subsequent measurement of debt issuance costs associated with line of credit arrangements. We do not expect this issued guidance, which will be adopted concurrently with ASU 2015-03, to have a material impact on our financial statements. In April 2015, the FASB issued ASU 2015-03, “Interest-Imputation of Interest,” which requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability. We do not expect this issued guidance, which is required to be adopted for our interim and annual reports for periods beginning after December 15, 2015, to have a material impact on our financial statements. In April 2015, the FASB issued ASU 2015-05, “Intangibles-Goodwill and Other-Internal-Use Software,” which helps entities evaluate the accounting for fees paid by a customer in a cloud computing arrangement. We are evaluating the impact of this issued guidance, which is required to be adopted for our interim and annual reports for periods beginning after December 15, 2015. In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers,” which clarifies and converges the revenue recognition principles under GAAP and International Financial Reporting Standards. In July 2015, FASB delayed the effective date for one year. We are evaluating the impact of this issued guidance, which is required to be adopted for our interim and annual reports beginning with the first quarter 2018.

DERIVATIVE FINANCIAL INSTRUME20

DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Policies)	9 Months Ended
	Sep. 30, 2015
Derivatives and Fair Value Measurement [Abstract]
Derivatives	Accounting Treatment - We record all derivative instruments at fair value, with the exception of normal purchases and normal sales that are expected to result in physical delivery. The accounting for changes in the fair value of a derivative instrument depends on whether it has been designated and qualifies as part of a hedging relationship and, if so, the reason for holding it, or if regulatory rulings require a different accounting treatment. If certain conditions are met, we may elect to designate a derivative instrument as a hedge to mitigate the risk of exposure to changes in fair values or cash flows. The table below summarizes the various ways in which we account for our derivative instruments and the impact on our financial statements: Recognition and Measurement Accounting Treatment Balance Sheet Income Statement Normal purchases and normal sales - Recorded at historical cost - Change in fair value not recognized in earnings Mark-to-market - Recorded at fair value - Change in fair value recognized in, and recoverable through, the purchased-gas cost adjustment mechanisms We have not elected to designate any of our derivative instruments as hedges. Premiums paid and any cash settlements received associated with the commodity derivative instruments entered into by us are included in, and recoverable through, the purchased-gas cost adjustment mechanisms.
Fair Value Measurement	Determining Fair Value - 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 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.

REGULATORY ASSETS AND LIABILI21

REGULATORY ASSETS AND LIABILITIES (Tables)	9 Months Ended
	Sep. 30, 2015
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: September 30, 2015 Current Noncurrent Total ( Thousands of dollars ) Under-recovered purchased-gas costs $ 10,354 $ — $ 10,354 Pension and postretirement benefit costs (see Note 8) 19,445 429,346 448,791 Reacquired debt costs 812 9,122 9,934 Other 1,092 1,844 2,936 Total regulatory assets, net of amortization 31,703 440,312 472,015 Accumulated removal costs (a) — (11,846 ) (11,846 ) Weather normalization (5,821 ) — (5,821 ) Over-recovered purchased-gas costs (33,363 ) — (33,363 ) Ad valorem tax (2,153 ) — (2,153 ) Total regulatory liabilities (41,337 ) (11,846 ) (53,183 ) Net regulatory assets (liabilities) $ (9,634 ) $ 428,466 $ 418,832 (a) Included in other deferred credits in our Balance Sheets. December 31, 2014 Current Noncurrent Total ( Thousands of dollars ) Under-recovered purchased-gas costs $ 28,712 $ — $ 28,712 Pension and postretirement benefit costs 18,108 466,684 484,792 Reacquired debt costs 812 9,730 10,542 Other 2,561 2,309 4,870 Total regulatory assets, net of amortization 50,193 478,723 528,916 Accumulated removal costs (a) — (15,451 ) (15,451 ) Weather normalization (16,516 ) — (16,516 ) Over-recovered purchased-gas costs (13,055 ) — (13,055 ) Ad valorem tax (2,896 ) — (2,896 ) Total regulatory liabilities (32,467 ) (15,451 ) (47,918 ) Net regulatory assets (liabilities) $ 17,726 $ 463,272 $ 480,998 (a) Included in other deferred credits in our Balance Sheets.

ACCUMULATED OTHER COMPREHENSI22

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	9 Months Ended
	Sep. 30, 2015
Accumulated Other Comprehensive Income (Loss) [Line Items]
Reclassification out of Accumulated Other Comprehensive Income [Table Text Block]	The following table sets forth the effect of reclassifications from accumulated other comprehensive income (loss) in our Statements of Income for the periods indicated: Three Months Ended Nine Months Ended Details about Accumulated Other Comprehensive September 30, September 30, Affected Line Item in the Income (Loss) Components 2015 2014 2015 2014 Statements of Income ( Thousands of dollars ) Pension and other postretirement benefit plan obligations (a) Amortization of net loss $ 12,564 $ 8,542 $ 37,694 $ 25,625 Amortization of unrecognized prior service cost (374 ) (303 ) (1,120 ) (909 ) 12,190 8,239 36,574 24,716 Regulatory adjustments (b) (11,961 ) (8,366 ) (35,887 ) (24,970 ) 229 (127 ) 687 (254 ) Income before income taxes (88 ) 49 (264 ) 98 Income tax expense Total reclassifications for the period $ 141 $ (78 ) $ 423 $ (156 ) Net income (a) These components of accumulated other comprehensive income (loss) are included in the computation of net periodic benefit cost. See Note 8 for additional detail of our net periodic benefit cost . (b) Regulatory adjustments represent pension and other postretirement benefit costs expected to be recovered through rates and are deferred as part of our regulatory assets. See Note 2 for additional disclosures of regulatory assets and liabilities.

EARNINGS PER SHARE (Tables)

EARNINGS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2015
EARNINGS PER SHARE [Line Items]
Schedule of Earnings Per Share, Basic and Diluted [Table Text Block]	The following tables set forth the computation of basic and diluted EPS from continuing operations for the periods indicated: Three Months Ended September 30, 2015 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 7,371 52,408 $ 0.14 Diluted EPS Calculation Effect of dilutive securities — 664 Net income available for common stock and common stock equivalents $ 7,371 53,072 $ 0.14 Three Months Ended September 30, 2014 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 4,653 52,361 $ 0.09 Diluted EPS Calculation Effect of dilutive securities — 653 Net income available for common stock and common stock equivalents $ 4,653 53,014 $ 0.09 Nine Months Ended September 30, 2015 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 79,828 52,627 $ 1.52 Diluted EPS Calculation Effect of dilutive securities — 688 Net income available for common stock and common stock equivalents $ 79,828 53,315 $ 1.50 Nine Months Ended September 30, 2014 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Calculation Net income available for common stock $ 73,183 52,353 $ 1.40 Diluted EPS Calculation Effect of dilutive securities — 495 Net income available for common stock and common stock equivalents $ 73,183 52,848 $ 1.38

EMPLOYEE BENEFIT PLANS (Tables)

EMPLOYEE BENEFIT PLANS (Tables)	9 Months Ended
	Sep. 30, 2015
Employee Benefit Plans [Line Items]
Schedule of Net Benefit Costs [Table Text Block]	The following tables set forth the components of net periodic benefit cost for our pension and other postretirement benefit plans for the periods indicated: Pension Benefits Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 ( Thousands of dollars ) Components of net periodic benefit cost Service cost $ 3,497 $ 3,554 $ 10,518 $ 9,227 Interest cost 10,652 10,948 31,956 32,844 Expected return on assets (15,363 ) (14,965 ) (46,087 ) (44,895 ) Amortization of unrecognized prior service cost 66 137 200 411 Amortization of net loss 11,054 7,550 33,164 22,649 Net periodic benefit cost $ 9,906 $ 7,224 $ 29,751 $ 20,236 Other Postretirement Benefits Three Months Ended Nine Months Ended September 30, September 30, 2015 2014 2015 2014 ( Thousands of dollars ) Components of net periodic benefit cost Service cost $ 849 $ 867 $ 2,547 $ 2,908 Interest cost 2,665 2,901 7,997 8,703 Expected return on assets (2,908 ) (2,848 ) (8,724 ) (8,544 ) Amortization of unrecognized prior service cost (440 ) (440 ) (1,320 ) (1,320 ) Amortization of net loss 1,510 992 4,530 2,976 Net periodic benefit cost $ 1,676 $ 1,472 $ 5,030 $ 4,723

SUMMARY OF SIGNIFICANT ACCOUN25

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) number in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Significant Accounting Policies [Line Items]
Number of natural gas distribution services customers	2		2
Segment Reporting, Disclosure of Major Customers	0	0	0	0

REGULATORY ASSETS AND LIABILI26

REGULATORY ASSETS AND LIABILITIES (Details) - USD ($) $ in Thousands	Sep. 30, 2015	Dec. 31, 2014
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Assets, Current	$ 31,703	$ 50,193
Regulatory Assets, Noncurrent	440,312	478,723
Regulatory Liability, Current	(41,337)	(32,467)
Net regulatory assets (liabilities), current	(9,634)	17,726
Net regulatory assets (liabilities), noncurrent	428,466	463,272
Net Regulatory Assets	418,832	480,998
Accumulated removal costs [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Liability, Current	0	0
Regulatory Liability, Noncurrent	(11,846)	(15,451)
Regulatory Liabilities	(11,846)	(15,451)
Weather normalization [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Liability, Current	(5,821)	(16,516)
Regulatory Liability, Noncurrent	0	0
Regulatory Liabilities	(5,821)	(16,516)
Over-recovered purchased-gas costs [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Liability, Current	(33,363)	(13,055)
Regulatory Liability, Noncurrent	0	0
Regulatory Liabilities	(33,363)	(13,055)
Ad valorem tax [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Liability, Current	(2,153)	(2,896)
Regulatory Liability, Noncurrent	0	0
Regulatory Liabilities	(2,153)	(2,896)
Total regulated liabilities [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Liability, Current	(41,337)	(32,467)
Regulatory Liability, Noncurrent	(11,846)	(15,451)
Regulatory Liabilities	(53,183)	(47,918)
Under-recovered purchased-gas costs [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Assets, Current	10,354	28,712
Regulatory Assets, Noncurrent	0	0
Regulatory Assets	10,354	28,712
Pension and postretirement benefit costs [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Assets, Current	19,445	18,108
Regulatory Assets, Noncurrent	429,346	466,684
Regulatory Assets	448,791	484,792
Reacquired debt costs [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Assets, Current	812	812
Regulatory Assets, Noncurrent	9,122	9,730
Regulatory Assets	9,934	10,542
Other regulatory assets [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Assets, Current	1,092	2,561
Regulatory Assets, Noncurrent	1,844	2,309
Regulatory Assets	2,936	4,870
Total regulatory assets, net of amortization [Member]
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
Regulatory Assets, Current	31,703	50,193
Regulatory Assets, Noncurrent	440,312	478,723
Regulatory Assets	$ 472,015	$ 528,916

CREDIT FACILITIES (Details)

CREDIT FACILITIES (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2015USD ($)	Dec. 31, 2014USD ($)
Line of Credit Facility [Line Items]
Ratio of Indebtedness to Net Capital	0.4
Commercial paper maximum borrowing capacity	$ 700,000
Commercial Paper	0	$ 42,000
Letters of Credit Outstanding, Amount	1,000
Line of Credit Facility, Remaining Borrowing Capacity	$ 699,000
Line of Credit [Member]
Line of Credit Facility [Line Items]
Debt Instrument, Covenant Description	The ONE Gas Credit Agreement contains certain financial, operational and legal covenants. Among other things, these covenants include maintaining ONE Gas’ debt-to-capital ratio of no more than 70 percent at the end of any calendar quarter. The ONE Gas Credit Agreement also contains customary affirmative and negative covenants, including covenants relating to liens, indebtedness of subsidiaries, investments, changes in the nature of business, fundamental changes, transactions with affiliates, burdensome agreements and use of proceeds. In the event of a breach of certain covenants by ONE Gas, amounts outstanding under the ONE Gas Credit Agreement may become due and payable immediately.
Line of Credit Facility, Interest Rate Description	Borrowings, if any, will accrue interest at LIBOR plus 79.5 basis points.
Line of credit facility sublimit	$ 50,000
Line Of Credit Facility Option To Increase Borrowing Capacity	1,200,000
Line of Credit Facility, Maximum Borrowing Capacity	$ 700,000
Line of Credit Facility, Commitment Fee Description	The annual facility fee is 8 basis points.

LONG-TERM DEBT (Details)

LONG-TERM DEBT (Details) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Debt Instrument [Line Items]
Cash payment to ONEOK upon separation	$ 0	$ (1,130,000)
Note Payable Due 2019 [Member]
Debt Instrument [Line Items]
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 aggregate principal amount of the outstanding Senior Notes to declare those senior notes immediately due and payable in full.
Long-term Debt, Gross	$ 300,000
Debt Instrument, Interest Rate, Stated Percentage	2.07%
Note Payable Due 2024 [Member]
Debt Instrument [Line Items]
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 aggregate principal amount of the outstanding Senior Notes to declare those senior notes immediately due and payable in full.
Long-term Debt, Gross	$ 300,000
Debt Instrument, Interest Rate, Stated Percentage	3.61%
Notes Payable Due 2044 [Member]
Debt Instrument [Line Items]
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 aggregate principal amount of the outstanding Senior Notes to declare those senior notes immediately due and payable in full.
Long-term Debt, Gross	$ 600,000
Debt Instrument, Interest Rate, Stated Percentage	4.658%

EQUITY DIVIDENDS (Details)

EQUITY DIVIDENDS (Details)	3 Months Ended
	Sep. 30, 2015$ / shares
Dividends Declared [Line Items]
Common Stock, Dividends, Per Share, Declared	$ 0.30
Common Stock, Dividends, Declared, Annualized Basis	$ 1.20

ACCUMULATED OTHER COMPREHENSI30

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Amortization of net loss	$ 12,564	$ 8,542	$ 37,694	$ 25,625
Amortization of unrecognized prior service cost	(374)	(303)	(1,120)	(909)
Reclassification adjustment, before tax and regulatory adjustments	12,190	8,239	36,574	24,716
Regulatory adjustments	(11,961)	(8,366)	(35,887)	(24,970)
Reclassification adjustment, before tax	229	(127)	687	(254)
Reclassification adjustment, Tax	(88)	49	(264)	98
Reclassification adjustment, net of tax	$ 141	$ (78)	$ 423	$ (156)

EARNINGS PER SHARE (Details)

EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014	Jan. 31, 2014
EARNINGS PER SHARE [Line Items]
Common stock, shares issued	52,598,005		52,598,005		52,083,859	51,941,236
Basic EPS Calculation
Net income available for common stock	$ 7,371	$ 4,653	$ 79,828	$ 73,183
Weighted Average Number of Shares Outstanding, Basic	52,408,000	52,361,000	52,627,000	52,353,000
Earnings Per Share, Basic	$ 0.14	$ 0.09	$ 1.52	$ 1.40
Diluted EPS Calculation
Net income available for common stock	$ 7,371	$ 4,653	$ 79,828	$ 73,183
Effect of dilutive securities on income	$ 0	$ 0	$ 0	$ 0
Effect of dilutive securities on shares	664,000	653,000	688,000	495,000
Weighted Average Number of Shares Outstanding, Diluted	53,072,000	53,014,000	53,315,000	52,848,000
Earnings Per Share, Diluted	$ 0.14	$ 0.09	$ 1.50	$ 1.38

EMPLOYEE BENEFIT PLANS (Details

EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Components of net periodic benefit cost:
Amortization of unrecognized prior service cost	$ (374)	$ (303)	$ (1,120)	$ (909)
Amortization of net loss	12,564	8,542	37,694	25,625
ONE Gas Pension Plans [Member]
Components of net periodic benefit cost:
Service cost	3,497	3,554	10,518	9,227
Interest cost	10,652	10,948	31,956	32,844
Expected return on assets	(15,363)	(14,965)	(46,087)	(44,895)
Amortization of unrecognized prior service cost	66	137	200	411
Amortization of net loss	11,054	7,550	33,164	22,649
Net periodic benefit cost	9,906	7,224	29,751	20,236
ONE Gas Postretirement Benefit Plans [Member]
Components of net periodic benefit cost:
Service cost	849	867	2,547	2,908
Interest cost	2,665	2,901	7,997	8,703
Expected return on assets	(2,908)	(2,848)	(8,724)	(8,544)
Amortization of unrecognized prior service cost	(440)	(440)	(1,320)	(1,320)
Amortization of net loss	1,510	992	4,530	2,976
Net periodic benefit cost	$ 1,676	$ 1,472	$ 5,030	$ 4,723

COMMITMENTS AND CONTINGENCIES33

COMMITMENTS AND CONTINGENCIES (Details)	Sep. 30, 2015
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 we have completed or addressed removal of the source of soil contamination according to plans approved by KDHE	11
Number of sites where regulatory closure has been achieved	3
Percentage yield of high consequence pipeline areas	30.00%

DERIVATIVE FINANCIAL INSTRUME34

DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2015USD ($)MMcf	Sep. 30, 2014USD ($)	Sep. 30, 2015USD ($)MMcf	Sep. 30, 2014USD ($)	Dec. 31, 2014USD ($)MMcf	Dec. 31, 2013USD ($)
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Derivative, Nonmonetary Notional Amount | MMcf	38,100		38,100		16,000
Premiums recorded in other current assets on natural gas contracts held	$ 11,600,000		$ 11,600,000		$ 6,400,000
Fair Value Assets, Transfers between Levels	0	$ 0	0	$ 0
Long-term Debt, including current maturities	1,201,306,000		1,201,306,000		1,201,311,000
Cash and Cash Equivalents, at Carrying Value	52,974,000	$ 59,685,000	52,974,000	$ 59,685,000	11,943,000	$ 3,171,000
Long-term Debt	1,200,000,000		1,200,000,000		1,200,000,000
Fair Value, Inputs, Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Fair value, natural gas call options	4,400,000		4,400,000		100,000
Fair Value, Inputs, Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
Long-term Debt, Fair Value	$ 1,200,000,000		$ 1,200,000,000		$ 1,300,000,000