ONE GAS, INC., 10-K/A filed on 2/27/2015
Amended Annual Report
Document And Entity Information (USD $)
In Billions, except Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Feb. 6, 2015
Jun. 30, 2014
Document Information [Line Items]
 
 
 
Entity Registrant Name
ONE Gas, Inc.  
 
 
Entity Central Index Key
0001587732 
 
 
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 Public Float
 
 
$ 1.9 
Entity Common Stock, Shares Outstanding
 
52,145,396 
 
Document Fiscal Year Focus
2014 
 
 
Document Fiscal Period Focus
FY 
 
 
Document Type
10-K/A 
 
 
Amendment Flag
true 
 
 
Amendment Description
This Amendment No. 1 to the annual report on Form 10-K of ONE Gas, Inc. (the “Company”) for the year ended December 31, 2014, originally filed on February 19, 2015, is being filed to correct a typographical error in the listing on the cover page of the number of shares of Common Stock outstanding as of February 6, 2015. The correct number of shares outstanding as of such date is 52,145,396, as indicated on the cover page of this Amendment No. 1. This Amendment No. 1 does not reflect events occurring after February 19, 2015 and does not update or modify in any way the results of operations, financial position, cash flows or other disclosures in the Company’s Form 10-K filed on February 19, 2015. As required by Rule 12b-15 under the Securities and Exchange Act of 1934, as amended, new certifications by our principal executive officer and principal financial officer are filed as exhibits to this Amendment No. 1 to the Company’s Form 10-K under Item 15 of Part IV. 
 
 
Document Period End Date
Dec. 31, 2014 
 
 
STATEMENTS OF INCOME (USD $)
In Thousands, except Per Share data, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Gross Margin
 
 
 
Revenues
$ 1,818,906 
$ 1,689,952 
$ 1,376,649 
Cost of natural gas
991,949 
876,944 
620,260 
Net margin
826,957 
813,008 
756,389 
Operating expenses
 
 
 
Operations and maintenance
420,686 
393,072 
363,120 
Depreciation and amortization
125,722 
144,758 
130,150 
General taxes
55,255 
54,830 
47,405 
Total operating expenses
601,663 
592,660 
540,675 
Operating income
225,294 
220,348 
215,714 
Other income
1,625 
6,165 
3,664 
Other expense
(2,949)
(3,680)
(2,225)
Interest expense
(45,842)
(61,366)
(60,793)
Income before income taxes
178,128 
161,467 
156,360 
Income taxes
(68,338)
(62,272)
(59,851)
Net income
$ 109,790 
$ 99,195 
$ 96,509 
Earnings per share (Note 7)
 
 
 
Basic
$ 2.10 
$ 1.90 
$ 1.84 
Diluted
$ 2.07 
$ 1.90 
$ 1.84 
Average shares (thousands)
 
 
 
Basic
52,364 
52,319 
52,319 
Diluted
52,946 
52,319 
52,319 
Dividends declared per share of stock
$ 0.84 
$ 0.00 
$ 0.00 
STATEMENTS OF COMPREHENSIVE INCOME STATEMENTS OF COMPREHENSIVE INCOME (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Net income
$ 109,790 
$ 99,195 
$ 96,509 
Other Comprehensive Income (Loss), Net of Tax [Abstract]
 
 
 
Change in pension and other postretirement benefit plans liability, net of tax of $1,244, $0, and $0, respectively
(1,781)
0 
0 
Other comprehensive loss
(1,781)
0 
0 
Comprehensive income
$ 108,009 
$ 99,195 
$ 96,509 
STATEMENTS OF COMPREHENSIVE INCOME (Parentheticals) (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
STATEMENTS OF COMPREHENSIVE INCOME [Abstract]
 
 
 
Pension and other postretirement benefit plans, Tax
$ 1,244 
$ 0 
$ 0 
BALANCE SHEETS (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Property, plant and equipment
 
 
Property, plant and equipment
$ 4,850,201 
$ 4,534,074 
Accumulated depreciation and amortization
1,556,481 
1,489,216 
Net property, plant and equipment (Note 10)
3,293,720 
3,044,858 
Current assets
 
 
Cash and cash equivalents
11,943 
3,171 
Accounts receivable, net
326,749 
356,988 
Income tax receivable
43,800 
0 
Natural gas in storage
185,300 
166,128 
Regulatory assets (Note 9)
50,193 
21,657 
Other current assets
49,516 
54,240 
Total current assets
667,501 
602,184 
Goodwill and other assets
 
 
Regulatory assets (Note 9)
478,723 
23,822 
Goodwill
157,953 
157,953 
Other assets
51,313 
17,658 
Total goodwill and other assets
687,989 
199,433 
Total assets
4,649,210 
3,846,475 
Equity and long-term debt
 
 
Common stock, $0.01 par value: authorized 250,000,000 shares; issued and outstanding 52,083,859 shares at December 31, 2014; authorized 1,000 shares, issued and outstanding 100 shares at December 31, 2013
521 
0 
Paid-in capital
1,758,796 
0 
Retained earnings
39,894 
0 
Accumulated other comprehensive income (loss)
(5,174)
0 
Owner's net investment
0 
1,239,023 
Total equity
1,794,037 
1,239,023 
Long-term debt, excluding current maturities
1,201,311 
1,318 
Long-term line of credit with ONEOK
0 
1,027,631 
Total equity and long-term debt
2,995,348 
2,267,972 
Current liabilities
 
 
Current maturities of long-term debt
6 
6 
Notes payable
42,000 
0 
Short-term note payable to ONEOK
0 
444,960 
Affiliate payables
0 
22,403 
Accounts payable
159,064 
169,500 
Accrued taxes other than income
44,742 
32,426 
Accrued liabilities
26,019 
4,791 
Customer deposits
60,003 
57,360 
Regulatory liability, current
32,467 
17,796 
Other current liabilities
28,132 
19,835 
Total current liabilities
392,433 
769,077 
Deferred credits and other liabilities [Abstract]
 
 
Deferred income taxes
894,585 
743,452 
Employee benefit obligations
287,779 
0 
Other deferred credits
79,065 
65,974 
Total deferred credits and other liabilities
1,261,429 
809,426 
Commitments and contingencies (Note 14)
   
   
Total liabilities and equity
$ 4,649,210 
$ 3,846,475 
BALANCE SHEETS BALANCE SHEETS Parenthetical (USD $)
Dec. 31, 2014
Dec. 31, 2013
Statement of Financial Position [Abstract]
 
 
Common Stock, Par or Stated Value Per Share
$ 0.01 
$ 0.01 
Common Stock, Shares Authorized
250,000,000 
1,000 
Common Stock, Shares, Issued
52,083,859 
100 
Common Stock, Shares, Outstanding
52,083,859 
100 
STATEMENTS OF CASH FLOWS (USD $)
In Thousands, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Net income
$ 109,790 
$ 99,195 
$ 96,509 
Adjustments to reconcile net income to net cash provided by operating activities:
 
 
 
Depreciation and amortization
125,722 
144,758 
130,150 
Deferred income taxes
49,935 
62,205 
59,491 
Share-based Compensation
7,613 
0 
0 
Provision for doubtful accounts
7,195 
5,460 
2,528 
Changes in assets and liabilities:
 
 
 
Accounts receivable
23,044 
(102,142)
10,016 
Income Tax Receivable
(43,800)
0 
0 
Natural gas in storage
(19,172)
(63,139)
30,154 
Asset removal costs
(47,125)
(46,567)
(47,658)
Affiliate payable
0 
(8,140)
(7,229)
Accounts payable
(6,881)
37,241 
(3,950)
Accrued taxes other than income
12,316 
2,449 
174 
Accrued Liabilities
21,228 
(5,443)
(4,511)
Customer deposits
2,643 
(727)
(1,254)
Regulatory assets and liabilities
30,067 
29,436 
(59,338)
Employee benefit obligation
(10,102)
0 
0 
Other assets and liabilities
(15,810)
(378)
(8,495)
Cash provided by operating activities
246,663 
154,208 
196,587 
Investing activities
 
 
 
Capital expenditures
(297,103)
(292,080)
(272,014)
Proceeds from sale of assets
0 
1,327 
1,462 
Cash used in investing activities
(297,103)
(290,753)
(270,552)
Financing activities
 
 
 
Settlement of short-term notes payable to ONEOK, net
0 
150,851 
58,692 
Borrowings on notes payable, net
42,000 
0 
0 
Issuance of debt, net of discounts
1,199,994 
0 
0 
Long-term debt financing costs
(11,087)
0 
0 
Borrowings on long-term line of credit with ONEOK
0 
0 
115,235 
Cash payment to ONEOK upon separation
(1,130,000)
0 
0 
Issuance of common stock
2,001 
0 
0 
Dividends paid
(43,696)
0 
0 
Repayment of long-term debt
0 
(206)
(330)
Distributions to ONEOK
0 
(14,969)
(100,067)
Cash provided by financing activities
59,212 
135,676 
73,530 
Change in cash and cash equivalents
8,772 
(869)
(435)
Cash and cash equivalents at beginning of period
3,171 
4,040 
4,475 
Cash and cash equivalents at end of period
11,943 
3,171 
4,040 
Supplemental cash flow information:
 
 
 
Cash paid for interest, net of amounts capitalized
21,066 
0 
0 
Cash paid to ONEOK for interest, net of amounts capitalized
0 
61,366 
60,793 
Cash paid for income taxes
44,603 
0 
0 
Cash paid to ONEOK for income taxes
$ 0 
$ 67 
$ 360 
STATEMENT OF CHANGES IN EQUITY (USD $)
In Thousands, except Share data
Total
Common Stock [Member]
Paid-in Capital [Member]
Retained Earnings [Member]
Owner's Net Investment [Member]
Accumulated Other Comprehensive Income (Loss) [Member]
Equity, beginning balance at Dec. 31, 2011
$ 1,158,355 
$ 0 
$ 0 
$ 0 
$ 1,158,355 
$ 0 
Shares Issued, beginning balance at Dec. 31, 2011
 
0 
 
 
 
 
Net income
96,509 
0 
0 
0 
96,509 
0 
Distributions to ONEOK
(100,067)
0 
0 
0 
(100,067)
0 
Other comprehensive loss
0 
 
 
 
 
 
Equity, ending balance at Dec. 31, 2012
1,154,797 
0 
0 
0 
1,154,797 
0 
Shares Issued, ending balance at Dec. 31, 2012
 
0 
 
 
 
 
Net income
99,195 
0 
0 
0 
99,195 
0 
Distributions to ONEOK
(14,969)
0 
0 
0 
(14,969)
0 
Other comprehensive loss
0 
 
 
 
 
 
Common stock issued, shares
 
100 
 
 
 
 
Common stock issued, value
0 
0 
0 
0 
0 
0 
Equity, ending balance at Dec. 31, 2013
1,239,023 
0 
0 
0 
1,239,023 
0 
Shares Issued, ending balance at Dec. 31, 2013
 
100 
 
 
 
 
Net income
109,790 
0 
0 
84,214 
25,576 
0 
Other comprehensive loss
(1,781)
0 
0 
0 
0 
(1,781)
Net transfers from ONEOK
481,086 
0 
0 
0 
484,479 
(3,393)
Reclassification of Owner's investment to paid-in capital
0 
0 
1,749,078 
0 
(1,749,078)
0 
Net issuance of common stock at the separation, Shares
 
51,941,136 
 
 
 
 
Common stock issued, shares
 
142,623 
 
 
 
 
Issuance of common stock at the separation, value
0 
520 
(520)
0 
0 
0 
Common stock issued, value
9,615 
1 
9,614 
0 
0 
0 
Equity, ending balance at Dec. 31, 2014
1,794,037 
521 
1,758,796 
39,894 
0 
(5,174)
Common stock dividends - $0.84 per share at Dec. 31, 2014
$ (43,696)
$ 0 
$ 624 
$ (44,320)
$ 0 
$ 0 
Shares Issued, ending balance at Dec. 31, 2014
 
52,083,859 
 
 
 
 
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Notes)
SIGNIFICANT ACCOUNTING POLICIES
1.
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES

Organization and Nature of Operations - ONE Gas, Inc. was a wholly owned subsidiary of ONEOK as of December 31, 2013. We are comprised of ONEOK’s former natural gas distribution business. On January 8, 2014, ONEOK’s board of directors approved the distribution of all the shares of our common stock to holders of ONEOK common stock. 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 through our divisions 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 assets and liabilities in the financial statements have been reflected on a historical basis. 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.

Because the operations of the natural gas distribution business within ONEOK were conducted through separate divisions, ONEOK’s net investment in us, excluding the long-term line of credit with ONEOK, is shown as owner’s net investment in lieu of equity in the financial statements prior to the separation. Transactions between ONEOK and us that were not part of the long-term line of credit with ONEOK or the short-term note payable to ONEOK have been identified in the Statements of Equity as a net transfer from ONEOK. Transactions with ONEOK’s other operating businesses, which generally settled monthly, are shown as accounts receivable-affiliate or accounts payable-affiliate in periods 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 year ended December 31, 2014, consist of the results of ONE Gas for the eleven months ended December 31, 2014, and the results of ONE Gas Predecessor for the one month ended January 31, 2014. Our Statements of Income and Comprehensive Income for the year ended December 31, 2013 and 2012, consist entirely of the results of ONE Gas Predecessor. Our net income for the period prior to January 31, 2014, was recorded to owner’s net investment.
•
Our balance sheet at December 31, 2014, consists of the balances of ONE Gas, while at December 31, 2013, it consists of the balances of ONE Gas and ONE Gas Predecessor.
•
Our Statement of Cash Flows for the year ended December 31, 2014, consists of the results of ONE Gas for the eleven months ended December 31, 2014, and the results of ONE Gas Predecessor for the one month ended January 31, 2014. Our Statements of Cash Flows for the year ended December 31, 2013 and 2012, consist entirely of the results of ONE Gas Predecessor.
•
Our Statements of Equity for the year ended December 31, 2014, consists of both the activity for ONE Gas Predecessor prior to January 31, 2014, and the activity for ONE Gas completed in connection with, and subsequent to, the separation on January 31, 2014. Our Statements of Equity for the years ended December 31, 2013 and 2012, consist entirely of the results of ONE Gas Predecessor.

The financial statements include the accounts of the natural gas distribution business as set forth in “Organization and Nature of Operations” above. All significant balances and transactions between our divisions have been eliminated.

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, 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 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.

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 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 8 for additional disclosures of our fair value measurements.

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. Prior to our separation, we participated in ONEOK’s cash management program rather than maintaining significant cash equivalent balances. Amounts due to ONEOK resulting from the cash management program were recorded as a short-term note payable to ONEOK. See Note 2 for additional information on the cash management program.

Revenue Recognition - For regulated deliveries of natural gas, we read meters and bill customers on a monthly cycle. We recognize revenues upon the delivery of the 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. Revenues are accrued for natural gas delivered and services rendered to customers, but not yet billed. 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 amounts of accrued unbilled natural gas sales revenues at December 31, 2014 and 2013, were $141.7 million and $143.7 million, respectively.

Accounts Receivable - Accounts receivable represent valid claims against nonaffiliated customers for natural gas sold or services rendered, net of allowances for doubtful accounts. We assess the creditworthiness of our customers. Those customers who do not meet minimum standards are required to provide security, including deposits and other forms of collateral, when appropriate. With more than 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. In Oklahoma, Kansas and most jurisdictions we serve in Texas, we are able to recover natural gas costs related to doubtful accounts through purchased-gas cost adjustment mechanisms. At December 31, 2014 and 2013, our allowance for doubtful accounts was $4.0 million and $3.3 million, respectively.

Inventories - Natural gas in storage is maintained 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, which are included in other current assets on our balance sheets, are stated at the lower of weighted-average cost or net realizable value. Our materials and supplies inventories totaled $27.5 million and $16.6 million at December 31, 2014 and 2013, respectively.

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 rulings require 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.

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
-
Fair value not recorded
-
Change in fair value not recognized in earnings
Mark-to-market
-
Recorded at fair value
-
Change in fair value recognized in, and
recoverable through, the purchased-gas cost adjustment mechanisms

We have not elected to designate any of our derivative instruments as hedges. Gains or losses associated with the fair value of commodity derivative instruments entered into by us are included in, and recoverable through, the purchased-gas cost adjustment mechanisms.

See Note 8 for more discussion of our fair value measurements and hedging activities using derivatives.

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 rate proceedings, and the changes in economic lives, if applicable, are implemented prospectively when the new rates are 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 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 10 for disclosures of 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. Total goodwill was $158.0 million at December 31, 2014 and 2013, respectively. Our goodwill impairment analysis performed in 2014, 2013 and 2012, utilized a qualitative assessment and did not result in any impairment indicators. Subsequent to July 1, 2014, no event has occurred indicating that it is more likely that not that our fair value is less than our carrying value of our net assets.

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 our carrying amount. If further testing is necessary, we perform a two-step impairment test for goodwill. In the first step, an initial assessment 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 indicated, and we must perform a second test to measure the amount of the impairment. In the second test, we calculate the implied fair value of the goodwill by deducting the fair value of all tangible and intangible net assets from the fair value determined in step one of the assessment. If the carrying value of the goodwill exceeds the implied fair value of the goodwill, we will record an impairment charge.

To estimate our 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 asset transactions. The forecasted cash flows are based on average forecasted cash flows over a period of years.

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 asset impairments in 2014, 2013 or 2012.

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, 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 rate payers. 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 the specific entity’s 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 9 for our regulatory asset and liability disclosures.

Pension and Other Postretirement Employee Benefits - We have defined benefit retirement plans covering certain full-time employees. We also sponsor welfare plans that provide postretirement medical and life insurance benefits to certain employees who retire with at least five years of service. Our actuarial consultant calculates the expense and liability related to these plans and uses statistical and other factors that attempt to anticipate future events. These factors include assumptions about the discount rate, expected return on plan assets, rate of future compensation increases, age and employment periods. 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.

Prior to the separation, certain employees participated in the Plans sponsored by ONEOK. We accounted for these plans as multiemployer benefit plans. Accordingly, we did not record an asset or liability to recognize the funded status of the Plans. We recognized a liability only for any required contributions to the Plans that were accrued and unpaid at the balance sheet date. The related pension and other postretirement expenses were allocated to us based on plan participants who directly supported our operations. These pension and other postretirement benefit costs included amounts associated with vested participants who are no longer employees.

Prior to the separation, certain benefit costs associated with employees who directly supported our operations were determined based on a specific employee basis. We were also allocated benefit costs associated with employees of ONEOK that provided general corporate services. These amounts were charged to us by ONEOK as described in Note 2. Prior to the separation, we were not the plan sponsor for the Plans. Accordingly, our balance sheets prior to the separation do not reflect any assets or liabilities related to the Plans. See Note 12 for additional information regarding pension and other postretirement employee benefit plans.

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 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 tax assets is recognized when it is more likely than not that some or all of the benefit from the deferred 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 tax liabilities, as well as the current and forecasted business economics of our industry. We had no valuation allowance at December 31, 2014 and 2013.

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, 2014 and 2013.

See Note 13 for additional discussion of 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 as long as natural gas supply and demand for natural gas distribution service exists. Based on the widespread use of natural gas for heating and cooking activities by residential and commercial customers in our service areas, management expects 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, 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; however, the amounts collected that are in excess of these nonlegal asset-removal costs incurred are accounted for as a regulatory liability for financial reporting purposes. Historically, with the exception of the regulatory authority in Kansas, the regulatory authorities that have jurisdiction over our regulated operations have not required us to quantify or disclose this amount; rather, these costs are addressed prospectively in depreciation rates and are set in each general rate order. We have made an estimate of our regulatory liability using current rates since the last general rate order in each of our jurisdictions; however, for financial reporting purposes, significant uncertainty exists regarding the future disposition of this regulatory liability, pending, among other issues, clarification of regulatory intent. We continue to monitor the regulatory requirements, and the liability may be adjusted as more information is obtained. We record the estimated asset removal obligation in noncurrent liabilities in other deferred credits on our balance sheets. To the extent this estimated liability is adjusted, such amounts will be reclassified between accumulated depreciation and amortization and other deferred credits 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 estimated losses from 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 14 for additional discussion of 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.

Prior to the separation, ONEOK charged us for compensation expense related to stock-based compensation awards granted to our employees that directly supported our operations. Share-based compensation was also a component of allocated amounts charged to us by ONEOK for general and administrative personnel providing services on our behalf.

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 to residential, commercial, industrial 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 (CEO). 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 and operating efficiency, not geographic location.

We evaluate performance based principally on operating income. Affiliate sales are recorded on the same basis as sales to unaffiliated customers and are discussed in further detail in Note 2. Net margin is comprised of total revenues less cost of natural gas. Cost of natural gas includes commodity purchases, fuel, storage and transportation costs and does not include an allocation of general operating costs or depreciation and amortization.

In 2014, 2013 and 2012, we had no single external customer from which we received 10 percent or more of our gross revenues.

Recently Issued Accounting Standards Update - 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. We are evaluating the impact of this recently issued guidance, which is required to be adopted for our quarterly and annual reports beginning with the first quarter 2017.
CREDIT FACILITY AND SHORT-TERM NOTES PAYABLE (Notes)
Short-term Debt [Text Block]
3.
CREDIT FACILITY AND SHORT-TERM NOTES PAYABLE

ONE Gas Credit Agreement - In December 2013, we entered into the ONE Gas Credit Agreement, which became effective upon our separation from ONEOK on January 31, 2014, and is scheduled to expire on January 31, 2019. The ONE Gas Credit Agreement contains certain financial, operational and legal covenants. Among other things, these covenants include maintaining ONE Gas’ total debt-to-capital ratio of no more than 70 percent at the end of any calendar quarter. 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 December 31, 2014, our total debt-to-capital ratio was 41 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 by either 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 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.

In July 2014, we entered into 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 sold generally 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 December 31, 2014, we had $42.0 million of commercial paper and $1.0 million in letters of credit issued under the ONE Gas Credit Agreement, with no borrowings and $657.0 million of remaining credit available under the ONE Gas Credit Agreement. The weighted-average interest rate on our commercial paper was 0.32 percent at December 31, 2014.
LONG-TERM DEBT (Notes)
Long-term Debt [Text Block]
4.
LONG-TERM DEBT

Senior notes issuance - In January 2014, we completed a private placement of senior notes, consisting of $300 million of 2.07 percent senior notes due 2019, $300 million of 3.61 percent senior notes due 2024 and $600 million of 4.658 percent senior notes due 2044 (collectively, our “Senior Notes”). The net proceeds from the private placement were approximately $1.19 billion and were used to fund a one-time cash payment to ONEOK of approximately $1.13 billion as part of the separation. The remaining portion of the net proceeds was retained in order to provide sufficient financial flexibility and to support working capital requirements and capital expenditures.

In connection with the issuance of our Senior Notes, we entered into a registration rights agreement, pursuant to which we were obligated to use our commercially reasonable efforts to file with the SEC and cause to become effective a registration statement with respect to an offer to exchange each series of Senior Notes for new notes, with terms substantially identical in all material respects to such series of our Senior Notes. Our registration statement, as amended, was declared effective by the SEC on September 5, 2014. We completed the noncash exchange of our Senior Notes for our registered senior notes in October 2014.

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.

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.
EQUITY (Notes)
Stockholders' Equity Note Disclosure [Text Block]
5.
EQUITY

Preferred Stock - At December 31, 2014, we have 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, 2014, we had approximately 197.9 million shares of authorized common stock available for issuance.

Treasury Shares - In February 2015, our Board of Directors authorized us to purchase treasury shares to be used to offset shares issued under our employee and non-employee director equity compensation, dividend reinvestment and employee stock purchase plans. The Board of Directors established an annual limit of $20 million of treasury stock purchases, exclusive of funds received through the dividend reinvestment and employee stock purchase plans. Stock purchases may be made in the open market or in private transactions at times, and in amounts that we deem appropriate. There is no guarantee as to the exact number of shares that we will purchase, and we can terminate or limit the program at any time. We may hold the purchased shares as treasury shares and will account for them using the cost method.

Dividends - Dividends paid totaled $43.7 million in 2014. The following table sets forth the dividends per share declared and paid on our common stock for the periods indicated:
 
 
2014
First Quarter
 
$
—

Second Quarter
 
$
0.28

Third Quarter
 
$
0.28

Fourth Quarter
 
$
0.28

Total
 
$
0.84



Additionally, a dividend of $0.30 per share ($1.20 per share on an annualized basis) was declared in January 2015, payable in the first quarter 2015.
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Notes)
Comprehensive Income (Loss) Note [Text Block]
6.
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)

The following table sets forth the balance in accumulated other comprehensive income (loss) for the period indicated:
 
 
Accumulated Other Comprehensive Income (Loss)
January 1, 2014
 
$
—

Transfers in upon separation
 
(3,393
)
Pension and other postretirement benefit plans obligations
 
 
Other comprehensive income (loss) before reclassification, net of tax of $1,442
 
(2,096
)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax of $(198)
 
315

Other comprehensive income (loss)
 
(1,781
)
December 31, 2014
 
$
(5,174
)


The following table sets forth the effect of reclassifications from accumulated other comprehensive income (loss) on our Statements of Income for the period indicated:
Details about Accumulated Other Comprehensive Income (Loss) Components
 
Year Ended December 31, 2014
Affected Line Item in the Statements of Income
 
 
(Thousands of dollars)
 
Pension and other postretirement benefit plan obligations (a)

 
 
 
Amortization of net loss

 
$
34,169

 
Amortization of unrecognized prior service cost
 
(1,211
)
 
 
 
32,958

 
Regulatory adjustments (b)
 
(32,445
)
 
 
 
513

Income before income taxes
 
 
(198
)
Income tax expense
Total reclassifications for the period
 
$
315

Net income
(a) These components of accumulated other comprehensive income (loss) are included in the computation of net periodic benefit cost. See Note 12 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 9 for additional disclosures of regulatory assets and liabilities.
EARNINGS PER SHARE (Notes)
Earnings Per Share [Text Block]
7.
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, 2014
 
Income
 
Shares
 
Per Share
Amount
 
(Thousands, except per share amounts)
Basic EPS Calculation
 
 
 
 
 
Net income available for common stock
$
109,790

 
52,364

 
$
2.10

Diluted EPS Calculation
 

 
 

 
 

Effect of dilutive securities
—

 
582

 
 

Net income available for common stock and common stock equivalents
$
109,790

 
52,946

 
$
2.07


 
Year Ended December 31, 2013
 
Income
 
Shares
 
Per Share
Amount
 
(Thousands, except per share amounts)
Basic EPS Calculation
 
 
 
 
 
Net income available for common stock
$
99,195

 
52,319

 
$
1.90

Diluted EPS Calculation
 
 
 

 
 

Effect of dilutive securities
—

 
—

 
 

Net income available for common stock and common stock equivalents
$
99,195

 
52,319

 
$
1.90


 
Year Ended December 31, 2012
 
Income
 
Shares
 
Per Share
Amount
 
(Thousands, except per share amounts)
Basic EPS Calculation
 
 
 
 
 
Net income available for common stock
$
96,509

 
52,319

 
$
1.84

Diluted EPS Calculation
 

 
 

 
 

Effect of dilutive securities
—

 
—

 
 

Net income available for common stock and common stock equivalents
$
96,509

 
52,319

 
$
1.84



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.
DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Notes)
Fair Value Disclosures
8.
DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS

Derivative Instruments - At December 31, 2014, we held purchased natural gas call options for the heating season ending 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. At December 31, 2013, we held purchased natural gas call options for the heating season ended March 2014, with total notional amounts of 26.6 Bcf, for which we paid premiums of $8.6 million, and had a fair value of $8.7 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 purchase 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 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 bank and money market accounts and are classified as Level 1.

The short-term notes payable were due upon demand and, therefore, the carrying amounts approximate fair value and are classified as Level 1. The estimated fair value and book value of our long-term debt, including current maturities, was $1.3 billion and $1.2 billion, respectively, at December 31, 2014. The estimated fair value of our Senior Notes was determined using quoted market prices, and are considered Level 2.

The estimated fair value and book value of our long-term line of credit with ONEOK at December 31, 2013, was $1.2 billion and $1.0 billion, respectively. The estimated fair value of our long-term line of credit with ONEOK was valued using the income approach by discounting the future payments and are considered Level 3. Significant unobservable inputs include the discount rate, which we estimated using a rate at which we could have borrowed at each measurement date.
REGULATORY ASSETS AND LIABILITIES (Notes)
Schedule of Regulatory Assets and Liabilities
9.
REGULATORY ASSETS AND LIABILITIES

The table below presents a summary of regulatory assets, net of amortization, and liabilities for the periods indicated:
 
 
 
 
December 31, 2014
 
 
Remaining Recovery Period
 
Current
 
Noncurrent
 
Total
 
 
 
 
(Thousands of dollars)
Under-recovered purchased-gas costs
 
1 year
 
$
28,712

 
$
—

 
$
28,712

Pension and other postretirement benefit costs
 
See Note 12
 
18,108

 
466,684

 
484,792

Reacquired debt costs
 
13 years
 
812

 
9,730

 
10,542

Other
 
1 to 24 years
 
2,561

 
2,309

 
4,870

Total regulatory assets, net of amortization
 
 
 
50,193

 
478,723

 
528,916

Accumulated removal costs (a)
 
up to 50 years
 
—

 
(15,451
)
 
(15,451
)
Weather normalization
 
1 year
 
(16,516
)
 
—

 
(16,516
)
Over-recovered purchased-gas costs
 
1 year
 
(13,055
)
 
—

 
(13,055
)
Ad valorem tax
 
1 year
 
(2,896
)
 
—

 
(2,896
)
Total regulatory liabilities
 
 
 
(32,467
)
 
(15,451
)
 
(47,918
)
Net regulatory assets and liabilities
 
 
 
$
17,726

 
$
463,272

 
$
480,998

(a) Included in other deferred credits in our balance sheets.
 
 
 
 
December 31, 2013
 
 
Remaining Recovery Period
 
Current
 
Noncurrent
 
Total
 
 
 
 
(Thousands of dollars)
Under-recovered purchased-gas costs
 
1 year
 
$
12,393

 
$
—

 
$
12,393

Pension and other postretirement benefit costs
 
See Note 12
 
298

 
9,556

 
9,854

Reacquired debt costs
 
14 years
 
812

 
10,541

 
11,353

Other
 
1 to 25 years
 
8,154

 
3,725

 
11,879

Total regulatory assets, net of amortization
 
 
 
21,657

 
23,822

 
45,479

Accumulated removal costs (a)
 
up to 50 years
 
—

 
(21,375
)
 
(21,375
)
Over-recovered purchased-gas costs
 
1 year
 
(17,796
)
 
—

 
(17,796
)
Total regulatory liabilities
 
 
 
(17,796
)
 
(21,375
)
 
(39,171
)
Net regulatory assets and liabilities
 
 
 
$
3,861

 
$
2,447

 
$
6,308

(a) Included in other deferred credits in our balance sheets.

Regulatory assets on our balance sheets, as authorized by the various regulatory commissions, are probable of recovery. Base rates are designed to provide a recovery of cost 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 recoverable through base rates are subject to review by the respective regulatory commissions during future rate proceedings. We are not aware of any evidence that these costs will not be recoverable through either rate riders or base rates, and we believe that we will be able to recover such costs, consistent with our historical recoveries.

Unrecovered purchased-gas costs represents the 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, premiums paid and any cash settlements received from our purchased natural gas call options.

We amortize reacquired debt costs in accordance with the accounting guidelines prescribed by the OCC and KCC.

In December 2013, the KCC approved a settlement agreement between ONEOK, the staff of the KCC, and the Citizens’ Utility Ratepayer Board that authorized the transfer of ONEOK’s Kansas Gas Service natural gas distribution assets to us. As a result, Kansas Gas Service expensed certain transition costs associated with ONEOK’s acquisition of Kansas Gas Service in 1997 that previously had been recorded as a regulatory asset and amortized and recovered in rates over a 40-year period. As such, we recorded a noncash charge to income of approximately $10.2 million before taxes during 2013 in depreciation and amortization.

Weather normalization represents revenue over- or under-recovered through the weather normalization adjustment 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 a rate case. 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.

Recovery through rates resulted in amortization of regulatory assets of approximately $6.4 million for the year ended December 31, 2014. Amortization of regulatory assets of approximately $32.0 million for the year ended December 31, 2013, included amounts recovered through rates totaling $21.8 million and $10.2 million related to certain transition costs as described above. Recovery through rates resulted in amortization of regulatory assets of approximately $18.3 million for the year ended December 31, 2012.
  
We collect, through our rates, the estimated costs of removal on certain regulated properties through depreciation expense, with a corresponding credit to accumulated depreciation and amortization. These removal costs are nonlegal obligations; however, the amounts collected that are in excess of these nonlegal asset-removal costs incurred are accounted for as a regulatory liability. We have made an estimate of our regulatory liability using current rates since the last general rate order in each of our jurisdictions. We record the estimated nonlegal asset removal obligation in noncurrent liabilities in other deferred credits on our balance sheets.
PROPERTY, PLANT AND EQUIPMENT (Notes)
PROPERTY, PLANT AND EQUIPMENT
10.
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,
 
 
2014
 
2013
 
 
(Thousands of dollars)
Natural gas distribution pipelines and related equipment
 
$
3,909,881

 
$
3,703,593

Natural gas transmission pipelines and related equipment
 
450,810

 
430,042

General plant and other
 
418,157

 
326,004

Construction work in process
 
71,353

 
74,435

Property, plant and equipment
 
4,850,201

 
4,534,074

Accumulated depreciation and amortization
 
(1,556,481
)
 
(1,489,216
)
Net property, plant and equipment
 
$
3,293,720

 
$
3,044,858



We compute depreciation expense for distribution operations by applying composite, straight-line rates approved by various regulatory agencies. The average depreciation rates for our property are set forth in the following table for the periods indicated:
Years Ended December 31,
2014
 
2013
 
2012
2.0% - 3.0%
 
2.0% - 3.0%
 
2.0% - 3.0%


We recorded capitalized interest of $2.5 million, $1.3 million and $1.3 million for the years ended December 31, 2014, 2013 and 2012, respectively. We incurred liabilities for construction work in process that had not been paid at December 31, 2014, 2013 and 2012 of $7.0 million, $10.5 million and $12.0 million, respectively. Such amounts are not included in capital expenditures on the Statements of Cash Flows.

Amounts recorded for regulatory accounting purposes that were not reflected in our financial statements were not material for the year ending December 31, 2014.
SHARE-BASED PAYMENTS (Notes)
Disclosure of Compensation Related Costs, Share-based Payments
11.
SHARE-BASED PAYMENTS

The ONE Gas Equity Compensation Plan (ECP or ONE Gas Plan) 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. We have reserved 2.8 million shares of common stock for issuance under the ECP. At December 31, 2014, we had approximately 1.3 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 Internal Revenue Code section 409A requirements.

Prior to our separation, certain employees assigned to us in the separation participated in ONEOK’s share-based awards plans (ONEOK Plans). The ONEOK Plans provided for ONEOK common stock based awards to both employees and ONEOK’s nonmanagement directors. The plans permitted the granting of various types of awards including, but not limited to, performance stock units and restricted stock units. Awards could be granted for no consideration other than prior and future services or based on certain financial performance targets. In connection with the separation, awards granted by ONEOK in 2012 and 2013 were cancelled and replaced with awards of ONE Gas shares. The number of restricted stock units held by a ONE Gas participant was multiplied by a ratio of 2.04 which was determined by the ONEOK volume-weighted average share price of $68.22 on January 31, 2014, and the ONE Gas volume-weighted average share price of $33.50 on February 3, 2014, rounded to the nearest whole share.

The same ratio of 2.04 was used to convert the outstanding performance stock units awarded by ONEOK prior to the separation into awards for ONE Gas shares. A pre-distribution payout factor was applied to each grant based on ONEOK’s total shareholder return performance compared with its peer group for the number of days lapsed from the date of the grant to January 31, 2014, and these awards were frozen or “banked” and are not subject to an additional payout factor. The remaining units from each grant will continue to be at-risk based on our performance and the relative total shareholder return of our peer group.

No incremental cost was recorded in our financial statements upon cancellation and replacement of the 2012 and 2013 restricted stock units and performance stock units because the previous awards were cancelled and replaced pursuant to anti-dilution provisions of the ONEOK Plans and the fair value of the awards immediately following the cancellation and replacement was not higher than the fair value of the awards immediately before the cancellation and replacement.

We were charged by ONEOK for share-based compensation expense related to employees that directly supported our operations. ONEOK also charged us for the allocated costs of certain employees of ONEOK (including stock-based compensation) who provided general and administrative services on our behalf. Information included in this note is limited to share-based compensation associated with employees in 2014, and employees that directly supported our operations as part of ONEOK prior to our separation. See Note 2 for total costs charged to us by ONEOK.

Compensation cost expensed for our share-based payment plans was $7.0 million, net of tax benefits of $4.4 million, for 2014. Compensation cost charged to us for employees directly supporting our operations by ONEOK for 2013 and 2012 totaled $9.7 million and $4.8 million, respectively, which is net of $6.1 million and $3.0 million of tax benefits, respectively. Compensation costs capitalized for employees were not material for 2014, 2013 and 2012.

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. The awards granted that replaced awards granted by ONEOK in 2012 vested, and 2013 will vest, consistent with their original vesting dates in 2015 and 2016, respectively. No dividends accrue prior to vesting on the restricted stock units granted that replaced the awards granted by ONEOK in 2012. Restricted stock unit awards granted in 2014 and that replaced awards granted by ONEOK in 2013 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, reduced by expected dividend payments for awards that do not accrue dividends 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. The awards granted that replaced awards granted by ONEOK in 2012 vested, and 2013 will vest, consistent with their original vesting dates in 2015 and 2016, respectively, if certain performance criteria are met by us for the at-risk portion of the awards as described above. 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 cost for these awards being recognized over the requisite service period, provided that the requisite service period is fulfilled, regardless of when, if ever, the market condition is satisfied. No dividends accrue prior to vesting on performance stock units granted to replace awards granted by ONEOK in 2012. The new performance stock unit awards granted in 2014 and the grants that replaced awards granted by ONEOK in 2013 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. A forfeiture rate of 3 percent per year based on historical forfeitures under our and, prior to the separation, ONEOK’s share-based payment plans was used. Compensation expense is recognized on a straight-line basis over the period of the award. The compensation expense on these awards will only be adjusted for changes in forfeitures.

Restricted Stock Unit Award Activity

As of December 31, 2014, there was $2.8 million of total unrecognized compensation costs related to the nonvested restricted stock unit awards, which is expected to be recognized over a weighted-average period of 1.8 years. The following tables set forth activity and various statistics for restricted stock unit awards outstanding under the respective plans for the period indicated:
 
 
ONE Gas Plan
 
ONEOK Plans
 
 
Number of
Shares
 
Weighted-
Average Price
 
Number of
Shares
 
Weighted-
Average Price
Nonvested December 31, 2013
 
—

 
$
—

 
137,670

 
$
34.57

Released to participants prior to separation
 
—

 
$
—

 
(66,960
)
 
$
28.50

Cancelled and replaced upon separation
 
246,683

 
$
19.71

 
(70,710
)
 
$
40.31

Granted
 
94,865

 
$
33.19

 
—

 
$
—

Released to participants
 
(7,217
)
 
$
19.85

 
—

 
$
—

Forfeited
 
(8,601
)
 
$
25.76

 
—

 
$
—

Nonvested December 31, 2014
 
325,730

 
$
23.47

 
—

 
$
—

 
 
2014
 
2013
 
2012
Weighted-average grant date fair value (per share)
 
$
33.19

 
$
47.36

 
$
36.60

Fair value of shares granted (thousands of dollars)
 
$
3,149

 
$
1,323

 
$
2,046



Performance Stock Unit Award Activity

As of December 31, 2014, there was $4.9 million of total unrecognized compensation cost 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, and ONEOK prior to 2014, in the valuations of the 2014, 2013 and 2012 grants at the grant date:
 
 
ONE Gas Plan
 
ONEOK Plans
 
 
Number of
Units
 
Weighted-
Average Price
 
Number of
Units
 
Weighted-
Average Price
Nonvested December 31, 2013
 
—

 
$
—

 
264,537

 
$
40.45

Released to participants prior to separation
 
—

 
$
—

 
(128,458
)
 
$
34.68

Cancelled and replaced upon separation
 
739,521

 
$
14.57

 
(136,079
)
 
$
45.90

Granted
 
124,015

 
$
35.98

 
—

 
$
—

Forfeited
 
(15,585
)
 
$
19.15

 
—

 
$
—

Nonvested December 31, 2014
 
847,951

 
$
17.62

 
—

 
$
—

 
 
2014
 
2013
 
2012
 
Volatility
 
18.40%
(a)
22.27%
(b)
27.00%
(b)
Dividend yield
 
3.37%
 
3.04%
 
2.86%
 
Risk-free interest rate
 
0.67%
 
0.42%
 
0.38%
 
(a) - Volatility based on historical volatility over three years using daily stock price observations of our peer utilities.
 
(b) - Volatility based on historical volatility over three years using daily ONEOK stock price observations.
 
 
 
2014
 
2013
 
2012
Weighted-average grant date fair value (per share)
 
$
35.98

 
$
52.30

 
$
42.39

Fair value of shares granted (thousands of dollars)
 
$
4,462

 
$
2,926

 
$
4,286



Employee Stock Purchase Plan

We have reserved a total of 0.7 million shares of common stock for issuance under our Employee Stock Purchase Plan (the ESPP).  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. Approximately 36 percent of employees participated in the plan in 2014 and purchased 51,418 shares at $32.29. Compensation expense, before taxes, was $0.4 million in 2014. All eligible employees of ONEOK were eligible to participate in a similar ESPP plan, but enrollment of our employees in that plan was terminated upon the separation. Compensation expense, before tax, charged to us by ONEOK for employees who directly supported our operations was $2.7 million and $0.8 million for 2013 and 2012, respectively.

Employee Stock Award Program

Under the program, each time the per-share closing price of our common stock on the NYSE closed for the first time at or above each $1.00 increment above its previous historical high closing price, we issued, for no monetary consideration, one share of our common stock to all eligible employees. Shares issued to employees under this program during 2014 totaled 35,324, and compensation expense, before taxes, related to the Employee Stock Award Program was $2.5 million. Compensation expense, before taxes, charged to us by ONEOK related to a similar program to ours that was administered by ONEOK for employees who directly supported our operations was $4.2 million and $1.2 million for 2013 and 2012, respectively.
EMPLOYEE BENEFIT PLANS (Notes)
Pension and Other Postretirement Benefits Disclosure [Text Block]
12.
EMPLOYEE BENEFIT PLANS

Retirement and Other Postretirement Benefit Plans

Prior to separation, certain employees participated in the Plans sponsored by ONEOK. We accounted for the Plans as multiemployer benefit plans. Accordingly, we did not record an asset or liability to recognize the funded status of the Plans. We recognized a liability only for any required contributions to the Plans that were accrued and unpaid at the balance sheet date. These defined benefit pension and other postretirement benefit costs included amounts associated with vested participants who are no longer employees. As described in Note 2, prior to 2014, ONEOK also charged us for the allocated cost of certain employees of ONEOK who provided general and administrative services on our behalf. ONEOK included an allocation of the benefit costs associated with these ONEOK employees based upon its allocation methodology, not necessarily specific to the employees providing general and administrative services on our behalf.

Retirement Plans - We have a defined benefit pension plan covering nonbargaining-unit employees hired before January 1, 2005, and certain bargaining-unit employees hired before December 15, 2011. Nonbargaining unit employees hired after December 31, 2004; employees represented by Local No. 304 of the International Brotherhood of Electrical Workers (IBEW) hired on or after July 1, 2010; employees represented by the United Steelworkers hired on or after December 15, 2011; and employees who accepted a one-time opportunity to opt out of the defined benefit pension plan are covered by a profit-sharing plan. Certain employees of the Texas Gas Services division were entitled to benefits under a frozen cash-balance pension plan. In addition, we have a supplemental executive retirement plan for the benefit of certain officers. No new participants in the supplemental executive retirement plan have been approved since 2005, and it was formally closed to new participants as of January 1, 2014. 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. Pension expense in 2014 was $27.1 million. Pension expense charged to us by ONEOK for employees directly supporting our operations totaled $35.0 million and $22.8 million for 2013 and 2012, respectively.

Other Postretirement Benefit Plans - We sponsor health and welfare plans that provide postretirement medical and life insurance benefits to certain employees who retire with at least five years of service. The postretirement 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. Other postretirement benefit expense in 2014 was $5.9 million. Other postretirement benefit expense charged to us by ONEOK for employees directly supporting our operations totaled $12.3 million and $16.6 million for 2013 and 2012, respectively.

Actuarial Assumptions - The following table sets forth the weighted-average assumptions used by us, and ONEOK prior to 2014, to determine the periodic benefit costs for the periods indicated:
 
 
Years Ended December 31,
 
 
2014
 
2013
 
2012
Discount rate - pension plans
 
5.25%
 
4.25%
 
5.00%
Discount rate - other postretirement plans
 
5.00%
 
4.00%
 
5.00%
Expected long-term return on plan assets
 
7.75%
 
8.25%
 
8.25%
Compensation increase rate
 
3.35% - 3.50%
 
3.45% - 3.50%
 
3.20% - 3.80%


We determine our overall expected long-term rate of return on plan assets, based on our review of historical returns and economic growth models. As of December 31, 2014, we updated our assumed mortality rates to incorporate the new set of mortality tables issued by the Society of Actuaries in October 2014.

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 postretirement 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 Treatment - The OCC, KCC and regulatory authorities in Texas have approved the recovery of pension costs and other postretirement 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 postretirement costs. Differences, if any, between the expense and the amount recovered through rates would be reflected in earnings, net of authorized deferrals. The KCC has authorized Kansas Gas Service’s recovery of defined benefit pension and other postretirement benefit costs in excess of the amounts included in rates over a period of 5 years.

We historically have recovered defined benefit pension and other postretirement benefit costs through rates. We believe it is probable that regulators will continue to include the net periodic pension and other postretirement benefit costs in our cost of service.

Obligations and Funded Status - In connection with the separation from ONEOK, we entered into an Employee Matters Agreement with ONEOK, which provides that our employees no longer participate in benefit plans sponsored or maintained by ONEOK as of the separation date. Effective January 1, 2014, the ONEOK defined benefit pension plans and other postretirement benefit plans transferred assets and obligations related to those employees transferring to ONE Gas and vested participants who are no longer employees to the new ONE Gas plans. As a result, we recorded sponsored pension and other postretirement plan obligations of approximately $1.1 billion, and sponsored defined benefit pension and other postretirement plan assets of approximately $1.0 billion, which are reflected below as our balances at the beginning of the period. Additionally, as a result of the transfer of unrecognized losses from ONEOK, our regulatory assets and deferred income taxes increased $331 million and $86 million, respectively.

The following table sets forth our defined benefit pension and other postretirement benefit plans, benefit obligations and fair value of plan assets for the periods indicated:

 
Pension Benefits
 
Other Postretirement Benefits
 
Year Ended December 31, 2014
Changes in Benefit Obligation
(Thousands of dollars)
Benefit obligation, beginning of period
$
863,620

 
$
239,171

Service cost
11,620

 
3,468

Interest cost
43,791

 
11,605

Plan participants’ contributions
—

 
2,642

Actuarial loss
159,275

 
14,998

Benefits paid
(50,135
)
 
(14,196
)
   Benefit obligation, end of period
1,028,171

 
257,688

 
 
 
 
Change in Plan Assets
 
 
 
Fair value of plan assets, beginning of period
840,699

 
147,237

Actual return on plan assets
53,907

 
6,912

Employer contributions
925

 
9,182

Plan participants’ contributions
—

 
2,642

Benefits paid
(50,135
)
 
(14,196
)
   Fair value of assets, end of period
845,396

 
151,777

   Balance at December 31
$
(182,775
)
 
$
(105,911
)
 
 
 
 
Current liabilities
$
(907
)
 
$
—

Noncurrent liabilities
(181,868
)
 
(105,911
)
   Balance at December 31
$
(182,775
)
 
$
(105,911
)


The accumulated benefit obligation for our defined benefit pension plans was $970.7 million at December 31, 2014.

There are no plan assets expected to be withdrawn and returned to us in 2015.

Components of Net Periodic Benefit Cost - The following table sets forth the components of net periodic benefit cost for our defined benefit pension and other postretirement benefit plans for the period indicated:

 
Pension Benefits
 
Other Postretirement Benefits
 
Year Ended December 31, 2014
 
(Thousands of dollars)
Components of net periodic benefit cost
 
 
 
Service cost
$
11,620

 
$
3,468

Interest cost
43,791

 
11,605

Expected return on assets
(59,862
)
 
(11,393
)
Amortization of unrecognized prior service cost
549

 
(1,760
)
Amortization of net loss
30,200

 
3,969

Settlements
773

 
—

   Net periodic benefit cost
$
27,071

 
$
5,889



Other Comprehensive Income (Loss) - The following table sets forth the amounts recognized in other comprehensive income (loss) related to our defined benefit pension benefits and other postretirement benefits for the period indicated:

 
Pension Benefits
 
Other Postretirement Benefits
 
Year Ended December 31, 2014
 
(Thousands of dollars)
Net loss arising during the period
$
(3,543
)
 
$
—

Amortization of loss
518

 
—

Deferred income taxes
1,244

 
—

   Total recognized in other comprehensive income (loss)
$
(1,781
)
 
$
—



The table below sets forth the amounts in accumulated other comprehensive income (loss) that had not yet been recognized as components of net periodic benefit expense for the period indicated:

 
Pension Benefits
 
Other Postretirement Benefits
 
December 31, 2014
 
(Thousands of dollars)
Prior service credit (cost)
$
(266
)
 
$
4,337

Accumulated loss
(426,862
)
 
(64,861
)
Accumulated other comprehensive loss
  before regulatory assets
(427,128
)
 
(60,524
)
Regulatory asset for regulated entities
418,699

 
60,524

Accumulated other comprehensive loss
  after regulatory assets
(8,429
)
 
—

Deferred income taxes
3,255

 
—

Accumulated other comprehensive loss,
  net of tax
$
(5,174
)
 
$
—



The following tables set forth the amounts recognized in either accumulated comprehensive income (loss) or regulatory assets expected to be recognized as components of net periodic benefit expense in the next fiscal year:


Pension Benefits

Other Postretirement Benefits
Amounts to be recognized in 2015
(Thousands of dollars)
Prior service credit (cost)
$
266


$
(1,760
)
Actuarial net loss
$
44,219


$
6,040



Health Care Cost Trend Rates - The following table sets forth the assumed health care cost-trend rates for the periods indicated:


2014
Health care cost-trend rate assumed for next year
4.00% - 7.75%
Rate to which the cost-trend rate is assumed to decline
  (the ultimate trend rate)
4.00% - 5.00%
Year that the rate reaches the ultimate trend rate
2022


Assumed health care cost-trend rates have a significant effect on the amounts reported for our health care plans. A one percentage point change in assumed health care cost-trend rates would have the following effects:


One Percentage

One Percentage

Point Increase

Point Decrease

(Thousands of dollars)
Effect on total of service and interest cost
$
484


$
(463
)
Effect on other postretirement benefit obligation
$
6,903


$
(6,675
)


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 plan reaches certain funded status. 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:

U.S. large-cap equities
37.4
%
Investment-grade bonds
30.0
%
Developed foreign large-cap equities
10.6
%
Alternative investments
7.7
%
Mid-cap equities
5.6
%
Emerging markets equities
5.0
%
Small-cap equities
3.7
%
  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 following tables set forth our pension benefits and other postretirement benefits plan assets by fair value category as of the measurement date:


Pension Benefits

December 31, 2014
Asset Category
Level 1
Level 2
Level 3
Total

(Thousands of dollars)
Investments:




Equity Securities (a)
$
439,165

$
66,766

$
—

$
505,931

Government obligations
—

47,769

—

47,769

Corporate obligations (b)
—

153,412

—

153,412

Cash and money market funds (c)
4,152

16,341

—

20,493

Insurance contracts and group annuity contracts
—

—

59,877

59,877

Other investments (d)
—

—

57,914

57,914

  Total assets
$
443,317

$
284,288

$
117,791

$
845,396

(a) - This category represents securities of the respective market sector from diverse industries.
(b) - This category represents bonds from diverse industries.
(c) - This category is primarily money market funds.
(d) - This category represents alternative investments such as hedge funds.

 
Other Postretirement Benefits
 
December 31, 2014
Asset Category
Level 1
Level 2
Level 3
Total
 
(Thousands of dollars)
Investments:
 
 
 
 
Equity Securities (a)
$
49,553

$
12,589

$
—

$
62,142

Government obligations
—

78

—

78

Corporate obligations (b)
—

251

—

251

Cash and money market funds (c)
964

5,894

—

6,858

Insurance contracts and group annuity contracts
—

82,353

—

82,353

Other investments (d)
—

—

95

95

  Total assets
$
50,517

$
101,165

$
95

$
151,777

(a) - This category represents securities of the respective market sector from diverse industries.
(b) - This category represents bonds from diverse industries.
(c) - This category is primarily money market funds.
(d) - This category represents alternative investments such as hedge funds.

The following table sets forth the reconciliation of Level 3 fair value measurements of our pension plans:

 
Pension Benefits
 
December 31, 2014
 
Insurance
Contracts
 
Other
Investments
 
Total
 
(Thousands of dollars)
January 1, 2014
$
63,454

 
$
73,590

 
$
137,044

Net realized and unrealized gains (losses)
3,446

 
(15,676
)
 
(12,230
)
Settlements
(7,023
)
 
—

 
(7,023
)
December 31, 2014
$
59,877

 
$
57,914

 
$
117,791



Contributions - During 2014, we contributed $0.9 million to our defined benefit pension plans and we contributed $9.2 million to our other postretirement benefit plans. In 2015, we expect to contribute $0.9 million to our defined benefit pension plans and expect to contribute $3.9 million to our other postretirement benefit plans.

Pension and Other Postretirement Benefit Payments - Benefit payments for our defined benefit pension and other postretirement benefit plans for the period ended December 31, 2014 were $50.1 million and $14.2 million, respectively. The following table sets forth the pension benefits and other postretirement benefits payments expected to be paid in 2015-2024:

 
Pension
Benefits
 
Other Postretirement
Benefits
Benefits to be paid in:
(Thousands of dollars)
2015
$
51,253

 
$
13,611

2016
$
52,366

 
$
14,283

2017
$
53,622

 
$
15,084

2018
$
55,068

 
$
15,776

2019
$
56,236

 
$
16,398

2020 through 2024
$
301,502

 
$
88,596



The expected benefits to be paid are based on the same assumptions used to measure our benefit obligation at December 31, 2014, 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 each participant’s eligible compensation, subject to certain limits. Our contributions made to the plan were $9.7 million in 2014. Prior to our separation, ONEOK maintained a similar 401(k) Plan and compensation expense charged to us for employees who directly supported our operations by ONEOK totaled $8.3 million and $8.4 million in 2013 and 2012, respectively for ONEOK’s matching contributions to this plan.

Profit-Sharing Plan - We have a profit-sharing plan for all nonbargaining unit employees hired after December 31, 2004, and employees covered by the IBEW collective bargaining agreement hired after June 30, 2010, and employees covered by USW collective bargaining agreement hired after December 15, 2011. Nonbargaining unit employees who were employed prior to January 1, 2005, employees covered by the IBEW collective bargaining agreement employed prior to July 1, 2010, and employees covered by the United Steelworker collective bargaining agreement employed prior to December 16, 2011, were given a one-time opportunity to make an irrevocable election to participate in the profit-sharing plan and not accrue any additional benefits under ONEOK’s defined benefit pension plan after December 31, 2004, and June 30, 2010, respectively. 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. Employee contributions are not allowed under the plan. Our contributions made to the plan were $4.0 million in 2014. ONEOK maintained a similar Profit-Sharing Plan and compensation expense associated with ONEOK’s contributions made to the plan for employees who directly supported our operations prior to the separation were $1.6 million and $2.1 million in 2013 and 2012, respectively.

Employee Deferred Compensation Plan - Our Nonqualified Deferred Compensation Plan provides select employees, as approved by our Board of Directors, with the option to defer portions of their compensation and provides nonqualified deferred compensation benefits that are not available due to limitations on employer and employee contributions to qualified defined contribution plans under the federal tax laws. Contributions made to the plan were not material in 2014. ONEOK maintained a similar plan and contributions made to the plan for employees who directly supported our operations prior to the separation were not material in 2013 and 2012.
INCOME TAXES (Notes)
INCOME TAXES
13.
INCOME TAXES

The following table sets forth our provision for income taxes for the periods indicated:

 
Years Ended December 31,
 
2014
 
2013
 
2012
 
(Thousands of dollars)
Current income tax provision
 
 
 
 
 
Federal
$
17,006

 
$
—

 
$
—

State
1,397

 
67

 
360

Total current income tax provision
18,403

 
67

 
360

Deferred income tax provision
 
 
 
 
 
Federal
42,024

 
53,562

 
51,481

State
7,911

 
8,643

 
8,010

Total deferred income tax provision
49,935

 
62,205

 
59,491

Total provision for income taxes
$
68,338

 
$
62,272

 
$
59,851



The following table is a reconciliation of our income tax provision for the periods indicated:
 
Years Ended December 31,
 
2014
 
2013
 
2012
 
(Thousands of dollars)
Income before income taxes
$
178,128

 
$
161,467

 
$
156,360

Federal statutory income tax rate
35
%
 
35
%
 
35
%
Provision for federal income taxes
62,345

 
56,513

 
54,726

State income taxes, net of federal tax benefit
6,051

 
5,661

 
5,423

Other, net
(58
)
 
98

 
(298
)
Total provision for income taxes
$
68,338

 
$
62,272

 
$
59,851



Prior to separation, our operations were included in the consolidated federal and state income tax returns of ONEOK. Our income tax provision was calculated on a separate return basis. Accordingly, we recognized deferred tax assets and liabilities for the difference between the financial statement and income tax basis of assets and liabilities and carry-forward items, based on income tax laws and rates existing at the time the temporary differences are expected to reverse as if we had been a corporation for federal and state income tax purposes. In addition, ONEOK managed its tax position based upon the tax attributes of the consolidated group. Certain attributes may not be available to use if we had been operating as an independent company.

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,
 
2014
 
2013
 
(Thousands of dollars)
Deferred tax assets
 
 
 
Employee benefits and other accrued liabilities
$
128,715

 
$
—

Net operating loss
8,144

 
40,125

Other
5,655

 
8,249

Total deferred tax assets
142,514

 
48,374

Deferred tax liabilities
 
 
 
Excess of tax over book depreciation
820,853

 
750,305

Purchased-gas cost adjustment
16,177

 
4,695

Other regulatory assets and liabilities, net
193,159

 
2,563

Total deferred tax liabilities
1,030,189

 
757,563

Net deferred tax liabilities
$
887,675

 
$
709,189



At December 31, 2014, we had income taxes receivable of $43.8 million. We had no income taxes payable or receivable at December 31, 2013.

In accordance with the Tax Matters Agreement, a cash settlement of $3.8 million is expected from ONEOK related to both the filing of ONEOK’s income tax return for the calendar year ended December 31, 2013 and for the January 1, 2014, through January 31, 2014 period. Our net deferred tax liabilities were adjusted to reflect this settlement.

The net operating loss of $8.1 million expires in 2035. We expect to utilize all of the net operating loss prior to its expiration date.
COMMITMENTS AND CONTINGENCIES (Notes)
COMMITMENTS AND CONTINGENCIES
14.
COMMITMENTS AND CONTINGENCIES

Commitments - Operating leases represent future minimum lease payments under noncancelable leases covering office space, facilities and information technology hardware and software. Rental expense was $5.0 million in 2014 and $4.8 million in each of 2013 and 2012. The following table sets forth our operating lease payments for the periods indicated:
Operating Leases
(Millions of dollars)
2015
 
$
4.7

2016
 
4.5

2017
 
4.3

2018
 
4.0

2019
 
3.4

Thereafter
 
10.4

Total
 
$
31.3




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 involves typically 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 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 2014, 2013 and 2012. We do not expect to incur material expenditures for these matters in the future.

Pipeline Safety - We are subject to PHMSA regulations, including integrity-management regulations. The Pipeline Safety Improvement Act requires pipeline companies operating high-pressure 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 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.
QUARTERLY FINANCIAL DATA (UNAUDITED) (Notes)
QUARTERLY FINANCIAL DATA (UNAUDITED)
15.
QUARTERLY FINANCIAL DATA (UNAUDITED)

 
 
First
Quarter
 
Second
Quarter
 
Third
Quarter
 
Fourth
Quarter
Year Ended December 31, 2014
 
 
 
 
 
 
(Thousands of dollars)
Revenues
 
$
766,178

 
$
296,838

 
$
241,522

 
$
514,368

Net margin
 
$
259,836

 
$
176,493

 
$
166,452

 
$
224,176

Operating income
 
$
109,353

 
$
26,812

 
$
19,119

 
$
70,010

Net income
 
$
59,076

 
$
9,454

 
$
4,653

 
$
36,607

Earnings per share
 
 
 
 
 
 
 
 
   Basic
 
$
1.13

 
$
0.18

 
$
0.09

 
$
0.70

   Diluted
 
$
1.13

 
$
0.18

 
$
0.09

 
$
0.69

 
 
First
Quarter
 
Second
Quarter
 
Third
Quarter
 
Fourth
Quarter
Year Ended December 31, 2013
 
 
 
 
 
 
(Thousands of dollars)
Revenues
 
$
635,933

 
$
311,608

 
$
219,725

 
$
522,686

Net margin
 
$
251,674

 
$
178,447

 
$
159,233

 
$
223,654

Operating income
 
$
101,838

 
$
39,307

 
$
14,189

 
$
65,014

Net income
 
$
53,492

 
$
14,951

 
$
434

 
$
30,318

Earnings per share
 
 
 
 
 
 
 
 
   Basic and diluted
 
$
1.02

 
$
0.29

 
$
0.01

 
$
0.58

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)
Basis of Accounting 
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 assets and liabilities in the financial statements have been reflected on a historical basis. 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.

Because the operations of the natural gas distribution business within ONEOK were conducted through separate divisions, ONEOK’s net investment in us, excluding the long-term line of credit with ONEOK, is shown as owner’s net investment in lieu of equity in the financial statements prior to the separation. Transactions between ONEOK and us that were not part of the long-term line of credit with ONEOK or the short-term note payable to ONEOK have been identified in the Statements of Equity as a net transfer from ONEOK. Transactions with ONEOK’s other operating businesses, which generally settled monthly, are shown as accounts receivable-affiliate or accounts payable-affiliate in periods 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 year ended December 31, 2014, consist of the results of ONE Gas for the eleven months ended December 31, 2014, and the results of ONE Gas Predecessor for the one month ended January 31, 2014. Our Statements of Income and Comprehensive Income for the year ended December 31, 2013 and 2012, consist entirely of the results of ONE Gas Predecessor. Our net income for the period prior to January 31, 2014, was recorded to owner’s net investment.
•
Our balance sheet at December 31, 2014, consists of the balances of ONE Gas, while at December 31, 2013, it consists of the balances of ONE Gas and ONE Gas Predecessor.
•
Our Statement of Cash Flows for the year ended December 31, 2014, consists of the results of ONE Gas for the eleven months ended December 31, 2014, and the results of ONE Gas Predecessor for the one month ended January 31, 2014. Our Statements of Cash Flows for the year ended December 31, 2013 and 2012, consist entirely of the results of ONE Gas Predecessor.
•
Our Statements of Equity for the year ended December 31, 2014, consists of both the activity for ONE Gas Predecessor prior to January 31, 2014, and the activity for ONE Gas completed in connection with, and subsequent to, the separation on January 31, 2014. Our Statements of Equity for the years ended December 31, 2013 and 2012, consist entirely of the results of ONE Gas Predecessor.

The financial statements include the accounts of the natural gas distribution business as set forth in “Organization and Nature of Operations” above. All significant balances and transactions between our divisions have been eliminated.
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, 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 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.
Fair Value Measurement 
Fair Value Measurements - We define fair value as the price that would be received from the sale of an asset or the transfer of a liability in an orderly transaction between market participants at the measurement date. We use the market and income approaches to determine the fair value of our assets and liabilities and consider the markets in which the transactions are executed. We measure the fair value of a group of financial assets and liabilities consistent with how a market participant would price the net risk exposure at the measurement date.

Fair Value Hierarchy - At each balance sheet date, we utilize a fair value hierarchy to classify fair value amounts recognized or disclosed in our 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 8 for additional disclosures of our fair value measurements.
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. Prior to our separation, we participated in ONEOK’s cash management program rather than maintaining significant cash equivalent balances. Amounts due to ONEOK resulting from the cash management program were recorded as a short-term note payable to ONEOK. See Note 2 for additional information on the cash management program.
Revenue Recognition 
Revenue Recognition - For regulated deliveries of natural gas, we read meters and bill customers on a monthly cycle. We recognize revenues upon the delivery of the 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. Revenues are accrued for natural gas delivered and services rendered to customers, but not yet billed. 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 amounts of accrued unbilled natural gas sales revenues at December 31, 2014 and 2013, were $141.7 million and $143.7 million, respectively.
Trade and Other Accounts Receivable 
Accounts Receivable - Accounts receivable represent valid claims against nonaffiliated customers for natural gas sold or services rendered, net of allowances for doubtful accounts. We assess the creditworthiness of our customers. Those customers who do not meet minimum standards are required to provide security, including deposits and other forms of collateral, when appropriate. With more than 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. In Oklahoma, Kansas and most jurisdictions we serve in Texas, we are able to recover natural gas costs related to doubtful accounts through purchased-gas cost adjustment mechanisms. At December 31, 2014 and 2013, our allowance for doubtful accounts was $4.0 million and $3.3 million, respectively.
Inventory 
Inventories - Natural gas in storage is maintained 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, which are included in other current assets on our balance sheets, are stated at the lower of weighted-average cost or net realizable value. Our materials and supplies inventories totaled $27.5 million and $16.6 million at December 31, 2014 and 2013, respectively.
Derivatives and Risk Management 
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 rulings require 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.

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
-
Fair value not recorded
-
Change in fair value not recognized in earnings
Mark-to-market
-
Recorded at fair value
-
Change in fair value recognized in, and
recoverable through, the purchased-gas cost adjustment mechanisms

We have not elected to designate any of our derivative instruments as hedges. Gains or losses associated with the fair value of commodity derivative instruments entered into by us are included in, and recoverable through, the purchased-gas cost adjustment mechanisms.

See Note 8 for more discussion of our fair value measurements and hedging activities using derivatives.
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 rate proceedings, and the changes in economic lives, if applicable, are implemented prospectively when the new rates are 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 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 10 for disclosures of our property, plant and equipment.

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. Total goodwill was $158.0 million at December 31, 2014 and 2013, respectively. Our goodwill impairment analysis performed in 2014, 2013 and 2012, utilized a qualitative assessment and did not result in any impairment indicators. Subsequent to July 1, 2014, no event has occurred indicating that it is more likely that not that our fair value is less than our carrying value of our net assets.

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 our carrying amount. If further testing is necessary, we perform a two-step impairment test for goodwill. In the first step, an initial assessment 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 indicated, and we must perform a second test to measure the amount of the impairment. In the second test, we calculate the implied fair value of the goodwill by deducting the fair value of all tangible and intangible net assets from the fair value determined in step one of the assessment. If the carrying value of the goodwill exceeds the implied fair value of the goodwill, we will record an impairment charge.

To estimate our 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 asset transactions. The forecasted cash flows are based on average forecasted cash flows over a period of years.

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 asset impairments in 2014, 2013 or 2012.
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, 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 rate payers. 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 the specific entity’s 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 9 for our regulatory asset and liability disclosures.
Pension and Other Postretirement Plans 
Pension and Other Postretirement Employee Benefits - We have defined benefit retirement plans covering certain full-time employees. We also sponsor welfare plans that provide postretirement medical and life insurance benefits to certain employees who retire with at least five years of service. Our actuarial consultant calculates the expense and liability related to these plans and uses statistical and other factors that attempt to anticipate future events. These factors include assumptions about the discount rate, expected return on plan assets, rate of future compensation increases, age and employment periods. 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.

Prior to the separation, certain employees participated in the Plans sponsored by ONEOK. We accounted for these plans as multiemployer benefit plans. Accordingly, we did not record an asset or liability to recognize the funded status of the Plans. We recognized a liability only for any required contributions to the Plans that were accrued and unpaid at the balance sheet date. The related pension and other postretirement expenses were allocated to us based on plan participants who directly supported our operations. These pension and other postretirement benefit costs included amounts associated with vested participants who are no longer employees.

Prior to the separation, certain benefit costs associated with employees who directly supported our operations were determined based on a specific employee basis. We were also allocated benefit costs associated with employees of ONEOK that provided general corporate services. These amounts were charged to us by ONEOK as described in Note 2. Prior to the separation, we were not the plan sponsor for the Plans. Accordingly, our balance sheets prior to the separation do not reflect any assets or liabilities related to the Plans. See Note 12 for additional information regarding pension and other postretirement employee benefit plans.

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 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 tax assets is recognized when it is more likely than not that some or all of the benefit from the deferred 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 tax liabilities, as well as the current and forecasted business economics of our industry. We had no valuation allowance at December 31, 2014 and 2013.

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, 2014 and 2013.

See Note 13 for additional discussion of 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 as long as natural gas supply and demand for natural gas distribution service exists. Based on the widespread use of natural gas for heating and cooking activities by residential and commercial customers in our service areas, management expects 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, 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; however, the amounts collected that are in excess of these nonlegal asset-removal costs incurred are accounted for as a regulatory liability for financial reporting purposes. Historically, with the exception of the regulatory authority in Kansas, the regulatory authorities that have jurisdiction over our regulated operations have not required us to quantify or disclose this amount; rather, these costs are addressed prospectively in depreciation rates and are set in each general rate order. We have made an estimate of our regulatory liability using current rates since the last general rate order in each of our jurisdictions; however, for financial reporting purposes, significant uncertainty exists regarding the future disposition of this regulatory liability, pending, among other issues, clarification of regulatory intent. We continue to monitor the regulatory requirements, and the liability may be adjusted as more information is obtained. We record the estimated asset removal obligation in noncurrent liabilities in other deferred credits on our balance sheets. To the extent this estimated liability is adjusted, such amounts will be reclassified between accumulated depreciation and amortization and other deferred credits and therefore will not have an impact on earnings.
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 estimated losses from 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 14 for additional discussion of contingencies.
Share-based Compensation, Option and Incentive Plans 
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.

Prior to the separation, ONEOK charged us for compensation expense related to stock-based compensation awards granted to our employees that directly supported our operations. Share-based compensation was also a component of allocated amounts charged to us by ONEOK for general and administrative personnel providing services on our behalf.
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.
Segment Reporting 
Segments - We operate in one reportable business segment: regulated public utilities that deliver natural gas to residential, commercial, industrial 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 (CEO). 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 and operating efficiency, not geographic location.

We evaluate performance based principally on operating income. Affiliate sales are recorded on the same basis as sales to unaffiliated customers and are discussed in further detail in Note 2. Net margin is comprised of total revenues less cost of natural gas. Cost of natural gas includes commodity purchases, fuel, storage and transportation costs and does not include an allocation of general operating costs or depreciation and amortization.

In 2014, 2013 and 2012, we had no single external customer from which we received 10 percent or more of our gross revenues.
New Accounting Pronouncements, Policy [Policy Text Block] 
Recently Issued Accounting Standards Update - 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. We are evaluating the impact of this recently issued guidance, which is required to be adopted for our quarterly and annual reports beginning with the first quarter 2017.
EQUITY (Tables)
Dividends Declared [Table Text Block]
Dividends - Dividends paid totaled $43.7 million in 2014. The following table sets forth the dividends per share declared and paid on our common stock for the periods indicated:
 
 
2014
First Quarter
 
$
—

Second Quarter
 
$
0.28

Third Quarter
 
$
0.28

Fourth Quarter
 
$
0.28

Total
 
$
0.84

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] 
The following table sets forth the balance in accumulated other comprehensive income (loss) for the period indicated:
 
 
Accumulated Other Comprehensive Income (Loss)
January 1, 2014
 
$
—

Transfers in upon separation
 
(3,393
)
Pension and other postretirement benefit plans obligations
 
 
Other comprehensive income (loss) before reclassification, net of tax of $1,442
 
(2,096
)
Amounts reclassified from accumulated other comprehensive income (loss), net of tax of $(198)
 
315

Other comprehensive income (loss)
 
(1,781
)
December 31, 2014
 
$
(5,174
)
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) on our Statements of Income for the period indicated:
Details about Accumulated Other Comprehensive Income (Loss) Components
 
Year Ended December 31, 2014
Affected Line Item in the Statements of Income
 
 
(Thousands of dollars)
 
Pension and other postretirement benefit plan obligations (a)

 
 
 
Amortization of net loss

 
$
34,169

 
Amortization of unrecognized prior service cost
 
(1,211
)
 
 
 
32,958

 
Regulatory adjustments (b)
 
(32,445
)
 
 
 
513

Income before income taxes
 
 
(198
)
Income tax expense
Total reclassifications for the period
 
$
315

Net income
(a) These components of accumulated other comprehensive income (loss) are included in the computation of net periodic benefit cost. See Note 12 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 9 for additional disclosures of regulatory assets and liabilities.
EARNINGS PER SHARE (Tables)
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, 2014
 
Income
 
Shares
 
Per Share
Amount
 
(Thousands, except per share amounts)
Basic EPS Calculation
 
 
 
 
 
Net income available for common stock
$
109,790

 
52,364

 
$
2.10

Diluted EPS Calculation
 

 
 

 
 

Effect of dilutive securities
—

 
582

 
 

Net income available for common stock and common stock equivalents
$
109,790

 
52,946

 
$
2.07


 
Year Ended December 31, 2013
 
Income
 
Shares
 
Per Share
Amount
 
(Thousands, except per share amounts)
Basic EPS Calculation
 
 
 
 
 
Net income available for common stock
$
99,195

 
52,319

 
$
1.90

Diluted EPS Calculation
 
 
 

 
 

Effect of dilutive securities
—

 
—

 
 

Net income available for common stock and common stock equivalents
$
99,195

 
52,319

 
$
1.90


 
Year Ended December 31, 2012
 
Income
 
Shares
 
Per Share
Amount
 
(Thousands, except per share amounts)
Basic EPS Calculation
 
 
 
 
 
Net income available for common stock
$
96,509

 
52,319

 
$
1.84

Diluted EPS Calculation
 

 
 

 
 

Effect of dilutive securities
—

 
—

 
 

Net income available for common stock and common stock equivalents
$
96,509

 
52,319

 
$
1.84

REGULATORY ASSETS AND LIABILITIES (Tables)
SCHEDULE OF REGULATED ASSETS AND LIABILITIES
The table below presents a summary of regulatory assets, net of amortization, and liabilities for the periods indicated:
 
 
 
 
December 31, 2014
 
 
Remaining Recovery Period
 
Current
 
Noncurrent
 
Total
 
 
 
 
(Thousands of dollars)
Under-recovered purchased-gas costs
 
1 year
 
$
28,712

 
$
—

 
$
28,712

Pension and other postretirement benefit costs
 
See Note 12
 
18,108

 
466,684

 
484,792

Reacquired debt costs
 
13 years
 
812

 
9,730

 
10,542

Other
 
1 to 24 years
 
2,561

 
2,309

 
4,870

Total regulatory assets, net of amortization
 
 
 
50,193

 
478,723

 
528,916

Accumulated removal costs (a)
 
up to 50 years
 
—

 
(15,451
)
 
(15,451
)
Weather normalization
 
1 year
 
(16,516
)
 
—

 
(16,516
)
Over-recovered purchased-gas costs
 
1 year
 
(13,055
)
 
—

 
(13,055
)
Ad valorem tax
 
1 year
 
(2,896
)
 
—

 
(2,896
)
Total regulatory liabilities
 
 
 
(32,467
)
 
(15,451
)
 
(47,918
)
Net regulatory assets and liabilities
 
 
 
$
17,726

 
$
463,272

 
$
480,998

(a) Included in other deferred credits in our balance sheets.
 
 
 
 
December 31, 2013
 
 
Remaining Recovery Period
 
Current
 
Noncurrent
 
Total
 
 
 
 
(Thousands of dollars)
Under-recovered purchased-gas costs
 
1 year
 
$
12,393

 
$
—

 
$
12,393

Pension and other postretirement benefit costs
 
See Note 12
 
298

 
9,556

 
9,854

Reacquired debt costs
 
14 years
 
812

 
10,541

 
11,353

Other
 
1 to 25 years
 
8,154

 
3,725

 
11,879

Total regulatory assets, net of amortization
 
 
 
21,657

 
23,822

 
45,479

Accumulated removal costs (a)
 
up to 50 years
 
—

 
(21,375
)
 
(21,375
)
Over-recovered purchased-gas costs
 
1 year
 
(17,796
)
 
—

 
(17,796
)
Total regulatory liabilities
 
 
 
(17,796
)
 
(21,375
)
 
(39,171
)
Net regulatory assets and liabilities
 
 
 
$
3,861

 
$
2,447

 
$
6,308

(a) Included in other deferred credits in our balance sheets.
PROPERTY, PLANT AND EQUIPMENT (Tables) (Regulated [Member])
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,
 
 
2014
 
2013
 
 
(Thousands of dollars)
Natural gas distribution pipelines and related equipment
 
$
3,909,881

 
$
3,703,593

Natural gas transmission pipelines and related equipment
 
450,810

 
430,042

General plant and other
 
418,157

 
326,004

Construction work in process
 
71,353

 
74,435

Property, plant and equipment
 
4,850,201

 
4,534,074

Accumulated depreciation and amortization
 
(1,556,481
)
 
(1,489,216
)
Net property, plant and equipment
 
$
3,293,720

 
$
3,044,858

Average Depreciation Rates for Regulated Property 
We compute depreciation expense for distribution operations by applying composite, straight-line rates approved by various regulatory agencies. The average depreciation rates for our property are set forth in the following table for the periods indicated:
Years Ended December 31,
2014
 
2013
 
2012
2.0% - 3.0%
 
2.0% - 3.0%
 
2.0% - 3.0%
SHARE-BASED PAYMENTS (Tables)
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:
 
 
ONE Gas Plan
 
ONEOK Plans
 
 
Number of
Shares
 
Weighted-
Average Price
 
Number of
Shares
 
Weighted-
Average Price
Nonvested December 31, 2013
 
—

 
$
—

 
137,670

 
$
34.57

Released to participants prior to separation
 
—

 
$
—

 
(66,960
)
 
$
28.50

Cancelled and replaced upon separation
 
246,683

 
$
19.71

 
(70,710
)
 
$
40.31

Granted
 
94,865

 
$
33.19

 
—

 
$
—

Released to participants
 
(7,217
)
 
$
19.85

 
—

 
$
—

Forfeited
 
(8,601
)
 
$
25.76

 
—

 
$
—

Nonvested December 31, 2014
 
325,730

 
$
23.47

 
—

 
$
—

 
 
2014
 
2013
 
2012
Weighted-average grant date fair value (per share)
 
$
33.19

 
$
47.36

 
$
36.60

Fair value of shares granted (thousands of dollars)
 
$
3,149

 
$
1,323

 
$
2,046

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, and ONEOK prior to 2014, in the valuations of the 2014, 2013 and 2012 grants at the grant date:
 
 
ONE Gas Plan
 
ONEOK Plans
 
 
Number of
Units
 
Weighted-
Average Price
 
Number of
Units
 
Weighted-
Average Price
Nonvested December 31, 2013
 
—

 
$
—

 
264,537

 
$
40.45

Released to participants prior to separation
 
—

 
$
—

 
(128,458
)
 
$
34.68

Cancelled and replaced upon separation
 
739,521

 
$
14.57

 
(136,079
)
 
$
45.90

Granted
 
124,015

 
$
35.98

 
—

 
$
—

Forfeited
 
(15,585
)
 
$
19.15

 
—

 
$
—

Nonvested December 31, 2014
 
847,951

 
$
17.62

 
—

 
$
—

 
 
2014
 
2013
 
2012
 
Volatility
 
18.40%
(a)
22.27%
(b)
27.00%
(b)
Dividend yield
 
3.37%
 
3.04%
 
2.86%
 
Risk-free interest rate
 
0.67%
 
0.42%
 
0.38%
 
(a) - Volatility based on historical volatility over three years using daily stock price observations of our peer utilities.
 
(b) - Volatility based on historical volatility over three years using daily ONEOK stock price observations.
 
 
 
2014
 
2013
 
2012
Weighted-average grant date fair value (per share)
 
$
35.98

 
$
52.30

 
$
42.39

Fair value of shares granted (thousands of dollars)
 
$
4,462

 
$
2,926

 
$
4,286

EMPLOYEE BENEFIT PLANS (Tables)
Schedule of Assumptions Used [Table Text Block] 
Actuarial Assumptions - The following table sets forth the weighted-average assumptions used by us, and ONEOK prior to 2014, to determine the periodic benefit costs for the periods indicated:
 
 
Years Ended December 31,
 
 
2014
 
2013
 
2012
Discount rate - pension plans
 
5.25%
 
4.25%
 
5.00%
Discount rate - other postretirement plans
 
5.00%
 
4.00%
 
5.00%
Expected long-term return on plan assets
 
7.75%
 
8.25%
 
8.25%
Compensation increase rate
 
3.35% - 3.50%
 
3.45% - 3.50%
 
3.20% - 3.80%
Schedule of Defined Benefit Plans Disclosures [Table Text Block] 
The following table sets forth our defined benefit pension and other postretirement benefit plans, benefit obligations and fair value of plan assets for the periods indicated:

 
Pension Benefits
 
Other Postretirement Benefits
 
Year Ended December 31, 2014
Changes in Benefit Obligation
(Thousands of dollars)
Benefit obligation, beginning of period
$
863,620

 
$
239,171

Service cost
11,620

 
3,468

Interest cost
43,791

 
11,605

Plan participants’ contributions
—

 
2,642

Actuarial loss
159,275

 
14,998

Benefits paid
(50,135
)
 
(14,196
)
   Benefit obligation, end of period
1,028,171

 
257,688

 
 
 
 
Change in Plan Assets
 
 
 
Fair value of plan assets, beginning of period
840,699

 
147,237

Actual return on plan assets
53,907

 
6,912

Employer contributions
925

 
9,182

Plan participants’ contributions
—

 
2,642

Benefits paid
(50,135
)
 
(14,196
)
   Fair value of assets, end of period
845,396

 
151,777

   Balance at December 31
$
(182,775
)
 
$
(105,911
)
 
 
 
 
Current liabilities
$
(907
)
 
$
—

Noncurrent liabilities
(181,868
)
 
(105,911
)
   Balance at December 31
$
(182,775
)
 
$
(105,911
)
Schedule of Net Benefit Costs [Table Text Block] 
Components of Net Periodic Benefit Cost - The following table sets forth the components of net periodic benefit cost for our defined benefit pension and other postretirement benefit plans for the period indicated:

 
Pension Benefits
 
Other Postretirement Benefits
 
Year Ended December 31, 2014
 
(Thousands of dollars)
Components of net periodic benefit cost
 
 
 
Service cost
$
11,620

 
$
3,468

Interest cost
43,791

 
11,605

Expected return on assets
(59,862
)
 
(11,393
)
Amortization of unrecognized prior service cost
549

 
(1,760
)
Amortization of net loss
30,200

 
3,969

Settlements
773

 
—

   Net periodic benefit cost
$
27,071

 
$
5,889

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) related to our defined benefit pension benefits and other postretirement benefits for the period indicated:

 
Pension Benefits
 
Other Postretirement Benefits
 
Year Ended December 31, 2014
 
(Thousands of dollars)
Net loss arising during the period
$
(3,543
)
 
$
—

Amortization of loss
518

 
—

Deferred income taxes
1,244

 
—

   Total recognized in other comprehensive income (loss)
$
(1,781
)
 
$
—

Schedule of Net Periodic Benefit Cost Not yet Recognized [Table Text Block] 
The table below sets forth the amounts in accumulated other comprehensive income (loss) that had not yet been recognized as components of net periodic benefit expense for the period indicated:

 
Pension Benefits
 
Other Postretirement Benefits
 
December 31, 2014
 
(Thousands of dollars)
Prior service credit (cost)
$
(266
)
 
$
4,337

Accumulated loss
(426,862
)
 
(64,861
)
Accumulated other comprehensive loss
  before regulatory assets
(427,128
)
 
(60,524
)
Regulatory asset for regulated entities
418,699

 
60,524

Accumulated other comprehensive loss
  after regulatory assets
(8,429
)
 
—

Deferred income taxes
3,255

 
—

Accumulated other comprehensive loss,
  net of tax
$
(5,174
)
 
$
—

Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year [Table Text Block] 
The following tables set forth the amounts recognized in either accumulated comprehensive income (loss) or regulatory assets expected to be recognized as components of net periodic benefit expense in the next fiscal year:


Pension Benefits

Other Postretirement Benefits
Amounts to be recognized in 2015
(Thousands of dollars)
Prior service credit (cost)
$
266


$
(1,760
)
Actuarial net loss
$
44,219


$
6,040

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:


2014
Health care cost-trend rate assumed for next year
4.00% - 7.75%
Rate to which the cost-trend rate is assumed to decline
  (the ultimate trend rate)
4.00% - 5.00%
Year that the rate reaches the ultimate trend rate
2022
Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block] 
Assumed health care cost-trend rates have a significant effect on the amounts reported for our health care plans. A one percentage point change in assumed health care cost-trend rates would have the following effects:


One Percentage

One Percentage

Point Increase

Point Decrease

(Thousands of dollars)
Effect on total of service and interest cost
$
484


$
(463
)
Effect on other postretirement benefit obligation
$
6,903


$
(6,675
)
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 plan reaches certain funded status. 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:

U.S. large-cap equities
37.4
%
Investment-grade bonds
30.0
%
Developed foreign large-cap equities
10.6
%
Alternative investments
7.7
%
Mid-cap equities
5.6
%
Emerging markets equities
5.0
%
Small-cap equities
3.7
%
  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 following tables set forth our pension benefits and other postretirement benefits plan assets by fair value category as of the measurement date:


Pension Benefits

December 31, 2014
Asset Category
Level 1
Level 2
Level 3
Total

(Thousands of dollars)
Investments:




Equity Securities (a)
$
439,165

$
66,766

$
—

$
505,931

Government obligations
—

47,769

—

47,769

Corporate obligations (b)
—

153,412

—

153,412

Cash and money market funds (c)
4,152

16,341

—

20,493

Insurance contracts and group annuity contracts
—

—

59,877

59,877

Other investments (d)
—

—

57,914

57,914

  Total assets
$
443,317

$
284,288

$
117,791

$
845,396

(a) - This category represents securities of the respective market sector from diverse industries.
(b) - This category represents bonds from diverse industries.
(c) - This category is primarily money market funds.
(d) - This category represents alternative investments such as hedge funds.

 
Other Postretirement Benefits
 
December 31, 2014
Asset Category
Level 1
Level 2
Level 3
Total
 
(Thousands of dollars)
Investments:
 
 
 
 
Equity Securities (a)
$
49,553

$
12,589

$
—

$
62,142

Government obligations
—

78

—

78

Corporate obligations (b)
—

251

—

251

Cash and money market funds (c)
964

5,894

—

6,858

Insurance contracts and group annuity contracts
—

82,353

—

82,353

Other investments (d)
—

—

95

95

  Total assets
$
50,517

$
101,165

$
95

$
151,777

(a) - This category represents securities of the respective market sector from diverse industries.
(b) - This category represents bonds from diverse industries.
(c) - This category is primarily money market funds.
(d) - This category represents alternative investments such as hedge funds.
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:

 
Pension Benefits
 
December 31, 2014
 
Insurance
Contracts
 
Other
Investments
 
Total
 
(Thousands of dollars)
January 1, 2014
$
63,454

 
$
73,590

 
$
137,044

Net realized and unrealized gains (losses)
3,446

 
(15,676
)
 
(12,230
)
Settlements
(7,023
)
 
—

 
(7,023
)
December 31, 2014
$
59,877

 
$
57,914

 
$
117,791

Schedule of Expected Benefit Payments [Table Text Block] 
The following table sets forth the pension benefits and other postretirement benefits payments expected to be paid in 2015-2024:

 
Pension
Benefits
 
Other Postretirement
Benefits
Benefits to be paid in:
(Thousands of dollars)
2015
$
51,253

 
$
13,611

2016
$
52,366

 
$
14,283

2017
$
53,622

 
$
15,084

2018
$
55,068

 
$
15,776

2019
$
56,236

 
$
16,398

2020 through 2024
$
301,502

 
$
88,596

INCOME TAXES (Tables)
Reconciliation of Income Tax Provision 
The following table sets forth our provision for income taxes for the periods indicated:

 
Years Ended December 31,
 
2014
 
2013
 
2012
 
(Thousands of dollars)
Current income tax provision
 
 
 
 
 
Federal
$
17,006

 
$
—

 
$
—

State
1,397

 
67

 
360

Total current income tax provision
18,403

 
67

 
360

Deferred income tax provision
 
 
 
 
 
Federal
42,024

 
53,562

 
51,481

State
7,911

 
8,643

 
8,010

Total deferred income tax provision
49,935

 
62,205

 
59,491

Total provision for income taxes
$
68,338

 
$
62,272

 
$
59,851

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,
 
2014
 
2013
 
2012
 
(Thousands of dollars)
Income before income taxes
$
178,128

 
$
161,467

 
$
156,360

Federal statutory income tax rate
35
%
 
35
%
 
35
%
Provision for federal income taxes
62,345

 
56,513

 
54,726

State income taxes, net of federal tax benefit
6,051

 
5,661

 
5,423

Other, net
(58
)
 
98

 
(298
)
Total provision for income taxes
$
68,338

 
$
62,272

 
$
59,851

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,
 
2014
 
2013
 
(Thousands of dollars)
Deferred tax assets
 
 
 
Employee benefits and other accrued liabilities
$
128,715

 
$
—

Net operating loss
8,144

 
40,125

Other
5,655

 
8,249

Total deferred tax assets
142,514

 
48,374

Deferred tax liabilities
 
 
 
Excess of tax over book depreciation
820,853

 
750,305

Purchased-gas cost adjustment
16,177

 
4,695

Other regulatory assets and liabilities, net
193,159

 
2,563

Total deferred tax liabilities
1,030,189

 
757,563

Net deferred tax liabilities
$
887,675

 
$
709,189

COMMITMENTS AND CONTINGENCIES (Tables)
Future Minimum Rental Payments for Operating Leases
The following table sets forth our operating lease payments for the periods indicated:
Operating Leases
(Millions of dollars)
2015
 
$
4.7

2016
 
4.5

2017
 
4.3

2018
 
4.0

2019
 
3.4

Thereafter
 
10.4

Total
 
$
31.3

QUARTERLY FINANCIAL DATA (UNAUDITED) (Tables)
Quarterly Financial Data
 
 
First
Quarter
 
Second
Quarter
 
Third
Quarter
 
Fourth
Quarter
Year Ended December 31, 2014
 
 
 
 
 
 
(Thousands of dollars)
Revenues
 
$
766,178

 
$
296,838

 
$
241,522

 
$
514,368

Net margin
 
$
259,836

 
$
176,493

 
$
166,452

 
$
224,176

Operating income
 
$
109,353

 
$
26,812

 
$
19,119

 
$
70,010

Net income
 
$
59,076

 
$
9,454

 
$
4,653

 
$
36,607

Earnings per share
 
 
 
 
 
 
 
 
   Basic
 
$
1.13

 
$
0.18

 
$
0.09

 
$
0.70

   Diluted
 
$
1.13

 
$
0.18

 
$
0.09

 
$
0.69

 
 
First
Quarter
 
Second
Quarter
 
Third
Quarter
 
Fourth
Quarter
Year Ended December 31, 2013
 
 
 
 
 
 
(Thousands of dollars)
Revenues
 
$
635,933

 
$
311,608

 
$
219,725

 
$
522,686

Net margin
 
$
251,674

 
$
178,447

 
$
159,233

 
$
223,654

Operating income
 
$
101,838

 
$
39,307

 
$
14,189

 
$
65,014

Net income
 
$
53,492

 
$
14,951

 
$
434

 
$
30,318

Earnings per share
 
 
 
 
 
 
 
 
   Basic and diluted
 
$
1.02

 
$
0.29

 
$
0.01

 
$
0.58

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Significant Accounting Policies [Line Items]
 
 
 
Unbilled Receivables, Current
$ 141,700,000 
$ 143,700,000 
 
Number of natural gas distribution services customers
2,000,000 
 
 
Allowance for Doubtful Accounts Receivable, Current
4,000,000 
3,300,000 
 
Materials, Supplies, and Other
27,500,000 
16,600,000 
 
Goodwill
157,953,000 
157,953,000 
 
Goodwill, Impairment Loss
0 
0 
0 
Asset Impairment Charges
0 
0 
0 
Deferred Tax Assets, Valuation Allowance
0 
0 
 
Liability for Uncertain Tax Positions, Current
$ 0 
$ 0 
 
Segment Reporting, Disclosure of Major Customers
0 
0 
0 
CREDIT FACILITY AND SHORT-TERM NOTES PAYABLE (Details) (USD $)
12 Months Ended 1 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Jan. 31, 2014
Line of Credit [Member]
Line of Credit Facility [Line Items]
 
 
 
Ratio of Indebtedness to Net Capital
0.41 
 
 
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’ total 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 sublimit
 
 
$ 50,000,000 
Line Of Credit Facility Option To Increase Borrowing Capacity
 
 
1,200,000,000 
Line of Credit Facility, Maximum Borrowing Capacity
 
 
700,000,000 
Line of Credit Facility, Interest Rate Description
 
 
Borrowings, if any, will accrue interest at LIBOR plus 79.5 basis points. 
Line of Credit Facility, Commitment Fee Description
 
 
The annual facility fee is 8 basis points. 
Commercial paper maximum borrowing capacity
700,000,000 
 
 
Commercial Paper
42,000,000 
0 
 
Letters of Credit Outstanding, Amount
1,000,000 
 
 
Line of Credit Facility, Remaining Borrowing Capacity
$ 657,000,000 
 
 
Short-term Debt, Weighted Average Interest Rate
0.32% 
 
 
LONG-TERM DEBT (Details) (USD $)
1 Months Ended
Jan. 31, 2014
Debt Instrument [Line Items]
 
Proceeds from Issuance of Private Placement
$ 1,190,000,000 
Cash Payment to ONEOK Upon Separation
1,130,000,000 
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 the aggregate principal amount of the outstanding Senior Notes to declare those senior notes immediately due and payable in full. 
Long-term Debt, Gross
300,000,000 
Debt Instrument, Interest Rate, Stated Percentage
2.07% 
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. 
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 the aggregate principal amount of the outstanding Senior Notes to declare those senior notes immediately due and payable in full. 
Long-term Debt, Gross
300,000,000 
Debt Instrument, Interest Rate, Stated Percentage
3.61% 
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 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 the aggregate principal amount of the outstanding Senior Notes to declare those senior notes immediately due and payable in full.  
Long-term Debt, Gross
$ 600,000,000 
Debt Instrument, Interest Rate, Stated Percentage
4.658% 
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. 
EQUITY (Details) (USD $)
In Millions, except Per Share data, unless otherwise specified
3 Months Ended 12 Months Ended 3 Months Ended
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jan. 31, 2014
Feb. 17, 2015
Subsequent Event [Member]
Mar. 31, 2015
Dividend Declared [Member]
Dividends declared per share of stock
$ 0.28 
$ 0.28 
$ 0.28 
$ 0.00 
$ 0.84 
$ 0.00 
$ 0.00 
 
 
 
Preferred Stock, Shares Authorized
50 
 
 
 
50 
 
 
50 
 
 
Preferred Stock, Par or Stated Value Per Share
$ 0.01 
 
 
 
$ 0.01 
 
 
 
 
 
Common stock authorized and available for issuance
197.9 
 
 
 
197.9 
 
 
 
 
 
Stock Repurchase Program, Authorized Amount
 
 
 
 
 
 
 
 
$ 20 
 
Payments of Dividends
 
 
 
 
$ 43.7 
 
 
 
 
 
Common Stock, Dividends, Per Share, Declared
 
 
 
 
 
 
 
 
 
$ 0.30 
Common Stock, Dividends, Declared, Annualized Basis
 
 
 
 
 
 
 
 
 
$ 1.20 
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) (USD $)
In Thousands, unless otherwise specified
1 Months Ended 12 Months Ended
Jan. 31, 2014
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss) [Line Items]
 
 
 
 
Pension and other postretirement benefit plans, Tax
 
$ 1,244 
$ 0 
$ 0 
Accumulated Other Comprehensive Income (Loss), beginning balance
0 
0 
 
 
Accumulated Other Comprehensive Income (Loss), ending balance
 
(5,174)
0 
 
Transfers in upon separation
3,393 
 
 
 
Pension and other postretirement benefit plans obligations [Abstract]
 
 
 
 
Other comprehensive income (loss), before reclassification, net of tax of $1,442
 
(2,096)
 
 
Amounts reclassified from accumulated other comprehensive income (loss), net of tax of $(198)
 
315 
 
 
Other comprehensive loss
 
(1,781)
0 
0 
Pension and other postretirement benefit plans obligations [Abstract]
 
 
 
 
Amortization of net loss
 
34,169 
 
 
Amortization of unrecognized prior service cost
 
1,211 
 
 
Other comprehensive income (loss) reclassification adjustment, before tax and regulatory adjustments
 
32,958 
 
 
Other comprehensive income (loss) reclassification - regulatory adjustments
 
(32,445)
 
 
Other comprehensive income (loss) reclassification adjustment, before tax
 
513 
 
 
Other comprehensive income (loss) reclassification adjustment, Tax
 
(198)
 
 
Other comprehensive income (loss) reclassification adjustment, net of tax
 
$ 315 
 
 
EARNINGS PER SHARE (Details) (USD $)
In Thousands, except Share data, unless otherwise specified
3 Months Ended 12 Months Ended
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jan. 31, 2014
EARNINGS PER SHARE OF COMMON STOCK, BASIC AND DILUTED [Line Items]
 
 
 
 
 
 
 
 
 
 
 
 
Common Stock, Shares, Issued
52,083,859 
 
 
 
100 
 
 
 
52,083,859 
100 
 
51,941,236 
Net income
$ 36,607 
$ 4,653 
$ 9,454 
$ 59,076 
$ 30,318 
$ 434 
$ 14,951 
$ 53,492 
$ 109,790 
$ 99,195 
$ 96,509 
 
Weighted Average Number of Shares Outstanding, Basic
 
 
 
 
 
 
 
 
52,364,000 
52,319,000 
52,319,000 
 
Earnings Per Share, Basic
$ 0.70 
$ 0.09 
$ 0.18 
$ 1.13 
 
 
 
 
$ 2.10 
$ 1.90 
$ 1.84 
 
Dilutive Securities, Effect on Basic Earnings Per Share
 
 
 
 
 
 
 
 
0 
0 
0 
 
Weighted Average Number Diluted Shares Outstanding Adjustment
 
 
 
 
 
 
 
 
582,000 
0 
0 
 
Net Income (Loss) Available to Common Stockholders, Diluted
 
 
 
 
 
 
 
 
$ 109,790 
$ 99,195 
$ 96,509 
 
Weighted Average Number of Shares Outstanding, Diluted
 
 
 
 
 
 
 
 
52,946,000 
52,319,000 
52,319,000 
 
Earnings Per Share, Diluted
$ 0.69 
$ 0.09 
$ 0.18 
$ 1.13 
 
 
 
 
$ 2.07 
$ 1.90 
$ 1.84 
 
DERIVATIVE FINANCIAL INSTRUMENTS AND FAIR VALUE MEASUREMENTS (Details) (USD $)
12 Months Ended
Dec. 31, 2014
MMcf
Dec. 31, 2013
MMcf
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
 
 
Derivative, Nonmonetary Notional Amount
16,000 
26,600 
Premiums recorded in other current assets on natural gas contracts held
$ 6,400,000 
$ 8,600,000 
Fair Value Assets, Transfers between Levels
0 
0 
Long-term Debt
1,200,000,000 
1,000,000,000 
Long-term line of credit with ONEOK
0 
1,027,631,000 
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
100,000 
8,700,000 
Fair Value, Inputs, Level 3 [Member]
 
 
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]
 
 
Long-term Debt, Fair Value
$ 1,300,000,000 
$ 1,200,000,000 
REGULATORY ASSETS AND LIABILITIES (Details) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
 
 
 
Amortization of Regulatory Asset
 
$ 32,000,000 
 
Amortization of Rate Deferral
6,400,000 
21,800,000 
18,300,000 
Regulatory Assets, Current
50,193,000 
21,657,000 
 
Regulatory Assets, Noncurrent
478,723,000 
23,822,000 
 
Regulatory Liability, Current
(32,467,000)
(17,796,000)
 
Net regulatory assets and liabilities, current
17,726,000 
3,861,000 
 
Net regulatory assets and liabilities, noncurrent
463,272,000 
2,447,000 
 
Net Regulatory Assets
480,998,000 
6,308,000 
 
Accumulated removal costs [Member]
 
 
 
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
 
 
 
Regulatory Asset, Amortization Period
up to 50 years 
up to 50 years 
 
Regulatory Liability, Current
0 
0 
 
Regulatory Liability, Noncurrent
(15,451,000)
(21,375,000)
 
Regulatory Liabilities
(15,451,000)
(21,375,000)
 
Weather normalization [Member]
 
 
 
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
 
 
 
Regulatory Asset, Amortization Period
1 year 
 
 
Regulatory Liability, Current
(16,516,000)
 
 
Regulatory Liability, Noncurrent
0 
 
 
Regulatory Liabilities
(16,516,000)
 
 
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
(13,055,000)
(17,796,000)
 
Regulatory Liability, Noncurrent
0 
0 
 
Regulatory Liabilities
(13,055,000)
(17,796,000)
 
Ad valorem tax [Member]
 
 
 
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
 
 
 
Regulatory Asset, Amortization Period
1 year 
 
 
Regulatory Liability, Current
(2,896,000)
 
 
Regulatory Liability, Noncurrent
0 
 
 
Regulatory Liabilities
(2,896,000)
 
 
Total regulated liabilities [Member]
 
 
 
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
 
 
 
Regulatory Liability, Current
(32,467,000)
(17,796,000)
 
Regulatory Liability, Noncurrent
(15,451,000)
(21,375,000)
 
Regulatory Liabilities
(47,918,000)
(39,171,000)
 
Natural Gas Transition Cost [Member]
 
 
 
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
 
 
 
Amortization of Regulatory Asset
 
10,200,000 
 
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
28,712,000 
12,393,000 
 
Regulatory Assets, Noncurrent
0 
0 
 
Regulatory Assets
28,712,000 
12,393,000 
 
Pension and postretirement benefit costs [Member]
 
 
 
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
 
 
 
Regulatory Asset, Amortization Period
See Note 12 
See Note 12 
 
Regulatory Assets, Current
18,108,000 
298,000 
 
Regulatory Assets, Noncurrent
466,684,000 
9,556,000 
 
Regulatory Assets
484,792,000 
9,854,000 
 
Reacquired debt costs [Member]
 
 
 
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
 
 
 
Regulatory Asset, Amortization Period
13 years 
14 years 
 
Regulatory Assets, Current
812,000 
812,000 
 
Regulatory Assets, Noncurrent
9,730,000 
10,541,000 
 
Regulatory Assets
10,542,000 
11,353,000 
 
Other regulatory assets [Member]
 
 
 
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
 
 
 
Regulatory Asset, Amortization Period
1 to 24 years 
1 to 25 years 
 
Regulatory Assets, Current
2,561,000 
8,154,000 
 
Regulatory Assets, Noncurrent
2,309,000 
3,725,000 
 
Regulatory Assets
4,870,000 
11,879,000 
 
Total regulatory assets, net of amortization [Member]
 
 
 
SCHEDULE OF REGULATED ASSETS AND LIABILITIES [Line Items]
 
 
 
Regulatory Assets, Current
50,193,000 
21,657,000 
 
Regulatory Assets, Noncurrent
478,723,000 
23,822,000 
 
Regulatory Assets
$ 528,916,000 
$ 45,479,000 
 
PROPERTY, PLANT AND EQUIPMENT (Details) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Property, Plant and Equipment [Line Items]
 
 
 
Property, plant and equipment
$ 4,850,201,000 
$ 4,534,074,000 
 
Accumulated depreciation and amortization
(1,556,481,000)
(1,489,216,000)
 
Net property, plant and equipment
3,293,720,000 
3,044,858,000 
 
Regulated [Member]
 
 
 
Property, Plant and Equipment [Line Items]
 
 
 
Property, plant and equipment
4,850,201,000 
4,534,074,000 
 
Accumulated depreciation and amortization
(1,556,481,000)
(1,489,216,000)
 
Net property, plant and equipment
3,293,720,000 
3,044,858,000 
 
Average depreciation rates, minimum
2.00% 
2.00% 
2.00% 
Average depreciation rates, maximum
3.00% 
3.00% 
3.00% 
Interest costs capitalized
2,500,000 
1,300,000 
1,300,000 
Construction work in process expenditures incurred but not yet paid
7,000,000 
10,500,000 
12,000,000 
Natural gas distribution pipelines and related equipment |
Regulated [Member]
 
 
 
Property, Plant and Equipment [Line Items]
 
 
 
Property, plant and equipment
3,909,881,000 
3,703,593,000 
 
Natural gas transmission pipelines and related equipment |
Regulated [Member]
 
 
 
Property, Plant and Equipment [Line Items]
 
 
 
Property, plant and equipment
450,810,000 
430,042,000 
 
General plant and other |
Regulated [Member]
 
 
 
Property, Plant and Equipment [Line Items]
 
 
 
Property, plant and equipment
418,157,000 
326,004,000 
 
Construction work in process |
Regulated [Member]
 
 
 
Property, Plant and Equipment [Line Items]
 
 
 
Property, plant and equipment
$ 71,353,000 
$ 74,435,000 
 
SHARE-BASED PAYMENTS (Details) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Feb. 3, 2014
Jan. 31, 2014
Share-based Payments [Line Items]
 
 
 
 
 
Share Price
 
 
 
 
$ 68.22 
Volume-weighted average share price of ONE Gas stock on February 3, 2014
 
 
 
$ 33.50 
 
Employee Stock Award Program Compensation Expense
$ 7,613,000 
$ 0 
$ 0 
 
 
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. 
 
 
 
 
Employee Stock Award Program [Member]
 
 
 
 
 
Share-based Payments [Line Items]
 
 
 
 
 
Description
Under the program, each time the per-share closing price of our common stock on the NYSE closed for the first time at or above each $1.00 increment above its previous historical high closing price, we issued, for no monetary consideration, one share of our common stock to all eligible employees. 
 
 
 
 
Restricted Stock Units (RSUs) [Member]
 
 
 
 
 
Share-based Payments [Line Items]
 
 
 
 
 
Share-based awards conversion ratio upon separation
 
 
 
 
2.04% 
Award vesting period
3 years 
 
 
 
 
Forfeiture rate maximum (in hundredths)
3.00% 
 
 
 
 
Total compensation cost not yet recognized
2,800,000 
 
 
 
 
Total compensation cost not yet recognized, period for recognition
1 year 9 months 18 days 
 
 
 
 
Performance Unit Awards [Member]
 
 
 
 
 
Share-based Payments [Line Items]
 
 
 
 
 
Share-based awards conversion ratio upon separation
 
 
 
 
2.04% 
Award vesting period
3 years 
 
 
 
 
Forfeiture rate maximum (in hundredths)
3.00% 
 
 
 
 
Total compensation cost not yet recognized
4,900,000 
 
 
 
 
Total compensation cost not yet recognized, period for recognition
1 year 8 months 12 days 
 
 
 
 
Employee Stock Purchase Plan [Member]
 
 
 
 
 
Share-based Payments [Line Items]
 
 
 
 
 
Common Stock, Capital Shares Reserved for Future Issuance
700,000 
 
 
 
 
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
36.00% 
 
 
 
 
Shares sold under employee stock purchase plan
51,418 
 
 
 
 
Share price of shares sold under Employee Stock Purchase Plan in dollars per share
$ 32.29 
 
 
 
 
Employee Stock Purchase Plan Compensation Expense
400,000 
2,700,000 
800,000 
 
 
Employee Stock Award Program [Member]
 
 
 
 
 
Share-based Payments [Line Items]
 
 
 
 
 
Shares issued to employees under the Employee Stock Award Program
35,324 
 
 
 
 
Employee Stock Award Program Compensation Expense
2,500,000 
4,200,000 
1,200,000 
 
 
ONEGAS Plan [Member]
 
 
 
 
 
Share-based Payments [Line Items]
 
 
 
 
 
Common Stock, Capital Shares Reserved for Future Issuance
2,800,000 
 
 
 
 
Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Available for Grant
1,300,000 
 
 
 
 
Share-based compensation expense, net of tax
7,000,000 
 
 
 
 
Share-based compensation, tax benefit
4,400,000 
 
 
 
 
ONEGAS Plan [Member] |
Restricted Stock Units (RSUs) [Member]
 
 
 
 
 
Share-based Payments [Line Items]
 
 
 
 
 
Released to participants prior to separation, number
0 
 
 
 
 
Released to participants prior to separation, weighted average fair value
$ 0.00 
 
 
 
 
Cancelled and replaced upon separation, number
(246,683)
 
 
 
 
Cancelled and replaced upon separation, weighted average fair value
$ 19.71 
 
 
 
 
Nonvested beginning balance (in units)
0 
 
 
 
 
Nonvested beginning balance (in dollars per unit)
$ 0.00 
 
 
 
 
Granted (in units)
94,865 
 
 
 
 
Weighted -average grant date fair value (per unit)
$ 33.19 
 
 
 
 
Released to participants (in units)
(7,217)
 
 
 
 
Released to participants (in dollars per unit)
$ 19.85 
 
 
 
 
Forfeited (in units)
(8,601)
 
 
 
 
Forfeited (in dollars per unit)
$ 25.76 
 
 
 
 
Nonvested ending balance (in units)
325,730 
 
 
 
 
Nonvested ending balance (in dollars per unit)
$ 23.47 
 
 
 
 
Fair value of shares granted (thousands of dollars)
3,149,000 
 
 
 
 
ONEGAS Plan [Member] |
Performance Unit Awards [Member]
 
 
 
 
 
Share-based Payments [Line Items]
 
 
 
 
 
Released to participants prior to separation, number
0 
 
 
 
 
Released to participants prior to separation, weighted average fair value
$ 0.00 
 
 
 
 
Cancelled and replaced upon separation, number
(739,521)
 
 
 
 
Cancelled and replaced upon separation, weighted average fair value
$ 14.57 
 
 
 
 
Nonvested beginning balance (in units)
0 
 
 
 
 
Nonvested beginning balance (in dollars per unit)
$ 0.00 
 
 
 
 
Granted (in units)
124,015 
 
 
 
 
Weighted -average grant date fair value (per unit)
$ 35.98 
 
 
 
 
Forfeited (in units)
(15,585)
 
 
 
 
Forfeited (in dollars per unit)
$ 19.15 
 
 
 
 
Nonvested ending balance (in units)
847,951 
 
 
 
 
Nonvested ending balance (in dollars per unit)
$ 17.62 
 
 
 
 
Fair value of shares granted (thousands of dollars)
4,462,000 
 
 
 
 
Expected volatility rate
18.40% 
 
 
 
 
Expected dividend yield
3.37% 
 
 
 
 
Risk-free interest rate
0.67% 
 
 
 
 
ONEOK Plans [Member]
 
 
 
 
 
Share-based Payments [Line Items]
 
 
 
 
 
Share-based compensation expense, net of tax
 
9,700,000 
4,800,000 
 
 
Share-based compensation, tax benefit
 
6,100,000 
3,000,000 
 
 
ONEOK Plans [Member] |
Restricted Stock Units (RSUs) [Member]
 
 
 
 
 
Share-based Payments [Line Items]
 
 
 
 
 
Released to participants prior to separation, number
(66,960)
 
 
 
 
Released to participants prior to separation, weighted average fair value
$ 28.50 
 
 
 
 
Cancelled and replaced upon separation, number
(70,710)
 
 
 
 
Cancelled and replaced upon separation, weighted average fair value
$ 40.31 
 
 
 
 
Nonvested beginning balance (in units)
137,670 
 
 
 
 
Nonvested beginning balance (in dollars per unit)
$ 34.57 
 
 
 
 
Granted (in units)
0 
 
 
 
 
Weighted -average grant date fair value (per unit)
$ 0.00 
$ 47.36 
$ 36.60 
 
 
Released to participants (in units)
0 
 
 
 
 
Released to participants (in dollars per unit)
$ 0.00 
 
 
 
 
Forfeited (in units)
0 
 
 
 
 
Forfeited (in dollars per unit)
$ 0.00 
 
 
 
 
Nonvested ending balance (in units)
0 
137,670 
 
 
 
Nonvested ending balance (in dollars per unit)
$ 0.00 
$ 34.57 
 
 
 
Fair value of shares granted (thousands of dollars)
 
1,323,000 
2,046,000 
 
 
ONEOK Plans [Member] |
Performance Unit Awards [Member]
 
 
 
 
 
Share-based Payments [Line Items]
 
 
 
 
 
Released to participants prior to separation, number
(128,458)
 
 
 
 
Released to participants prior to separation, weighted average fair value
$ 34.68 
 
 
 
 
Cancelled and replaced upon separation, number
(136,079)
 
 
 
 
Cancelled and replaced upon separation, weighted average fair value
$ 45.90 
 
 
 
 
Nonvested beginning balance (in units)
264,537 
 
 
 
 
Nonvested beginning balance (in dollars per unit)
$ 40.45 
 
 
 
 
Granted (in units)
0 
 
 
 
 
Weighted -average grant date fair value (per unit)
$ 0.00 
$ 52.30 
$ 42.39 
 
 
Forfeited (in units)
0 
 
 
 
 
Forfeited (in dollars per unit)
$ 0.00 
 
 
 
 
Nonvested ending balance (in units)
0 
264,537 
 
 
 
Nonvested ending balance (in dollars per unit)
$ 0.00 
$ 40.45 
 
 
 
Fair value of shares granted (thousands of dollars)
 
$ 2,926,000 
$ 4,286,000 
 
 
Expected volatility rate
 
22.27% 
27.00% 
 
 
Expected dividend yield
 
3.04% 
2.86% 
 
 
Risk-free interest rate
 
0.42% 
0.38% 
 
 
EMPLOYEE BENEFIT PLANS (Details) (USD $)
1 Months Ended 12 Months Ended
Jan. 31, 2014
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Defined Benefit Plans and Other Postretirement 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 postretirement medical and life insurance benefits
 
5 
 
 
Expected long-term return on plan assets
 
7.75% 
8.25% 
8.25% 
Compensation increase rate - minimum
 
3.35% 
3.45% 
3.20% 
Compensation increase rate- maximum
 
3.50% 
3.50% 
3.80% 
Description of basis used to determine overall expected long-term rate of return on plan assets
 
We determine our overall expected long-term rate of return on plan assets, based on our review of historical returns and economic growth models. As of December 31, 2014, we updated our assumed mortality rates to incorporate the new set of mortality tables issued by the Society of Actuaries in October 2014. 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 postretirement 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. 
 
 
Increase in regulatory assets as a result of the transfer of unrecognized losses from ONEOK
$ 331,000,000 
 
 
 
Increase in deferred income taxes as a result of the transfer of unrecognized losses from ONEOK
86,000,000 
 
 
 
Benefit obligation, beginning of period
1,100,000,000 
1,100,000,000 
 
 
Fair value of plan assets, beginning of period
1,000,000,000 
1,000,000,000 
 
 
Noncurrent liabilities
 
(287,779,000)
0 
 
Defined Benefit Plan, Amount and Timing of Assets Expected to be Returned to Employer During Following 12 Month Period
 
0 
 
 
Amortization of unrecognized prior service cost
 
(1,211,000)
 
 
Amortization of loss
 
34,169,000 
 
 
Total recognized in other comprehensive income (loss)
 
1,781,000 
0 
0 
Year that the rate reaches the ultimate trend rate
 
2022 
 
 
Defined Benefit Plan, Target Plan Asset Allocations
 
100.00% 
 
 
Maximum [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Health care cost-trend rate assumed for next year
 
7.75% 
 
 
Rate to which the cost-trend rate is assumed to decline (the ultimate trend rate)
 
5.00% 
 
 
Minimum [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Health care cost-trend rate assumed for next year
 
4.00% 
 
 
Rate to which the cost-trend rate is assumed to decline (the ultimate trend rate)
 
4.00% 
 
 
ONEOK Profit-Sharing Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Expense charged to us by ONEOK, Inc.
 
 
1,600,000 
2,100,000 
Expense charged to us by ONEOK, Inc.
 
 
1,600,000 
2,100,000 
ONE Gas 401(k) Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
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
 
9,700,000 
 
 
ONEOK 401(k) Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Expense charged to us by ONEOK, Inc.
 
 
8,300,000 
8,400,000 
Expense charged to us by ONEOK, Inc.
 
 
8,300,000 
8,400,000 
ONE Gas Profit-Sharing Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Profit sharing contribution percentage
 
1.00% 
 
 
Contributions made to profit-sharing plan
 
4,000,000 
 
 
US Large-Cap Equity [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Defined Benefit Plan, Target Plan Asset Allocations
 
37.40% 
 
 
Investment-grade bonds [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Defined Benefit Plan, Target Plan Asset Allocations
 
30.00% 
 
 
Developed foreign large-cap equities [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Defined Benefit Plan, Target Plan Asset Allocations
 
10.60% 
 
 
Alternative investments [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Defined Benefit Plan, Target Plan Asset Allocations
 
7.70% 
 
 
Mid-cap equities [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Defined Benefit Plan, Target Plan Asset Allocations
 
5.60% 
 
 
Emerging market equities [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Defined Benefit Plan, Target Plan Asset Allocations
 
5.00% 
 
 
Small-cap equities [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Defined Benefit Plan, Target Plan Asset Allocations
 
3.70% 
 
 
Pension Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Net periodic benefit cost
 
27,071,000 
35,000,000 
22,800,000 
Discount rate
 
5.25% 
4.25% 
5.00% 
Benefit obligation
 
1,028,171,000 
 
 
Fair value of plan assets
 
845,396,000 
 
 
Benefit obligation, beginning of period
863,620,000 
863,620,000 
 
 
Service cost
 
11,620,000 
 
 
Plan participants' contributions
 
0 
 
 
Actuarial loss
 
159,275,000 
 
 
Benefits paid
 
(50,135,000)
 
 
Benefit obligation, end of period
 
1,028,171,000 
 
 
Fair value of plan assets, beginning of period
840,699,000 
840,699,000 
 
 
Actual return on plan assets
 
53,907,000 
 
 
Employer contributions
 
925,000 
 
 
Plan participants' contributions
 
0 
 
 
Benefits paid
 
(50,135,000)
 
 
Fair value of plan assets, end of period
 
845,396,000 
 
 
Balance at December 31
 
(182,775,000)
 
 
Current liabilities
 
(907,000)
 
 
Noncurrent liabilities
 
(181,868,000)
 
 
Balance at December 31
 
(182,775,000)
 
 
Accumulated benefit obligation for defined benefit pension plans
 
970,700,000 
 
 
Service cost
 
11,620,000 
 
 
Interest cost
 
43,791,000 
 
 
Expected return on plan assets
 
(59,862,000)
 
 
Amortization of unrecognized prior service cost
 
549,000 
 
 
Amortization of loss
 
30,200,000 
 
 
Settlements
 
773,000 
 
 
Net periodic benefit cost
 
27,071,000 
35,000,000 
22,800,000 
Net loss arising during the period
 
(3,543,000)
 
 
Defined Benefit Plan, Future Amortization of Gain (Loss)
 
518,000 
 
 
Deferred income taxes
 
1,244,000 
 
 
Total recognized in other comprehensive income (loss)
 
(1,781,000)
 
 
Prior service credit (cost)
 
(266,000)
 
 
Accumulated loss
 
(426,862,000)
 
 
Accumulated other comprehensive loss before regulatory assets
 
(427,128,000)
 
 
Regulatory asset for regulated entities
 
418,699,000 
 
 
Accumulated other comprehensive loss after regulatory assets
 
(8,429,000)
 
 
Deferred income taxes
 
3,255,000 
 
 
Accumulated other comprehensive loss, net of tax
 
(5,174,000)
 
 
Prior service credit (cost) expected to be recognized in following fiscal year
 
266,000 
 
 
Actuarial net loss, to be recognized in 2015
 
44,219,000 
 
 
Effect of a one percentage point change on total of service and interest cost - increase
 
484,000 
 
 
Effect of a one percentage point change on other postretirement benefit obligation - increase
 
6,903,000 
 
 
Level 3 fair value measurement, January 1
137,044,000 
137,044,000 
 
 
Net realized and unrealized gains (losses)
 
(12,230,000)
 
 
Settlements
 
(7,023,000)
 
 
Level 3 fair value measurement, December 31
 
117,791,000 
 
 
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year
 
900,000 
 
 
2015
 
51,253,000 
 
 
2016
 
52,366,000 
 
 
2017
 
53,622,000 
 
 
2018
 
55,068,000 
 
 
2019
 
56,236,000 
 
 
2020 through 2024
 
301,502,000 
 
 
Pension Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
443,317,000 
 
 
Fair value of plan assets, end of period
 
443,317,000 
 
 
Pension Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
284,288,000 
 
 
Fair value of plan assets, end of period
 
284,288,000 
 
 
Pension Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
117,791,000 
 
 
Fair value of plan assets, end of period
 
117,791,000 
 
 
Other Postretirement Benefit Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement 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 postretirement medical and life insurance benefits
 
5 
 
 
Net periodic benefit cost
 
5,889,000 
12,300,000 
16,600,000 
Discount rate
 
5.00% 
4.00% 
5.00% 
Benefit obligation
 
257,688,000 
 
 
Fair value of plan assets
 
151,777,000 
 
 
Benefit obligation, beginning of period
239,171,000 
239,171,000 
 
 
Service cost
 
3,468,000 
 
 
Plan participants' contributions
 
2,642,000 
 
 
Actuarial loss
 
14,998,000 
 
 
Benefits paid
 
(14,196,000)
 
 
Benefit obligation, end of period
 
257,688,000 
 
 
Fair value of plan assets, beginning of period
147,237,000 
147,237,000 
 
 
Actual return on plan assets
 
6,912,000 
 
 
Employer contributions
 
9,182,000 
 
 
Plan participants' contributions
 
2,642,000 
 
 
Benefits paid
 
(14,196,000)
 
 
Fair value of plan assets, end of period
 
151,777,000 
 
 
Balance at December 31
 
(105,911,000)
 
 
Current liabilities
 
0 
 
 
Noncurrent liabilities
 
(105,911,000)
 
 
Balance at December 31
 
(105,911,000)
 
 
Service cost
 
3,468,000 
 
 
Interest cost
 
11,605,000 
 
 
Expected return on plan assets
 
(11,393,000)
 
 
Amortization of unrecognized prior service cost
 
(1,760,000)
 
 
Amortization of loss
 
3,969,000 
 
 
Settlements
 
0 
 
 
Net periodic benefit cost
 
5,889,000 
12,300,000 
16,600,000 
Net loss arising during the period
 
0 
 
 
Defined Benefit Plan, Future Amortization of Gain (Loss)
 
0 
 
 
Deferred income taxes
 
0 
 
 
Total recognized in other comprehensive income (loss)
 
0 
 
 
Prior service credit (cost)
 
4,337,000 
 
 
Accumulated loss
 
(64,861,000)
 
 
Accumulated other comprehensive loss before regulatory assets
 
(60,524,000)
 
 
Regulatory asset for regulated entities
 
60,524,000 
 
 
Accumulated other comprehensive loss after regulatory assets
 
0 
 
 
Deferred income taxes
 
0 
 
 
Accumulated other comprehensive loss, net of tax
 
0 
 
 
Prior service credit (cost) expected to be recognized in following fiscal year
 
(1,760,000)
 
 
Actuarial net loss, to be recognized in 2015
 
6,040,000 
 
 
Effect of a one percentage point change on total of service and interest cost - decrease
 
(463,000)
 
 
Effect of a one percentage point change on other postretirement benefit obligation - decrease
 
(6,675,000)
 
 
Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year
 
3,900,000 
 
 
2015
 
13,611,000 
 
 
2016
 
14,283,000 
 
 
2017
 
15,084,000 
 
 
2018
 
15,776,000 
 
 
2019
 
16,398,000 
 
 
2020 through 2024
 
88,596,000 
 
 
Other Postretirement Benefit Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
50,517,000 
 
 
Fair value of plan assets, end of period
 
50,517,000 
 
 
Other Postretirement Benefit Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
101,165,000 
 
 
Fair value of plan assets, end of period
 
101,165,000 
 
 
Other Postretirement Benefit Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
95,000 
 
 
Fair value of plan assets, end of period
 
95,000 
 
 
Equity Securities [Member] |
Pension Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
505,931,000 
 
 
Fair value of plan assets, end of period
 
505,931,000 
 
 
Equity Securities [Member] |
Pension Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
439,165,000 
 
 
Fair value of plan assets, end of period
 
439,165,000 
 
 
Equity Securities [Member] |
Pension Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
66,766,000 
 
 
Fair value of plan assets, end of period
 
66,766,000 
 
 
Equity Securities [Member] |
Pension Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Equity Securities [Member] |
Other Postretirement Benefit Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
62,142,000 
 
 
Fair value of plan assets, end of period
 
62,142,000 
 
 
Equity Securities [Member] |
Other Postretirement Benefit Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
49,553,000 
 
 
Fair value of plan assets, end of period
 
49,553,000 
 
 
Equity Securities [Member] |
Other Postretirement Benefit Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
12,589,000 
 
 
Fair value of plan assets, end of period
 
12,589,000 
 
 
Equity Securities [Member] |
Other Postretirement Benefit Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Cash and Money Market Funds [Member] |
Pension Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
20,493,000 
 
 
Fair value of plan assets, end of period
 
20,493,000 
 
 
Cash and Money Market Funds [Member] |
Pension Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
4,152,000 
 
 
Fair value of plan assets, end of period
 
4,152,000 
 
 
Cash and Money Market Funds [Member] |
Pension Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
16,341,000 
 
 
Fair value of plan assets, end of period
 
16,341,000 
 
 
Cash and Money Market Funds [Member] |
Pension Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Cash and Money Market Funds [Member] |
Other Postretirement Benefit Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
6,858,000 
 
 
Fair value of plan assets, end of period
 
6,858,000 
 
 
Cash and Money Market Funds [Member] |
Other Postretirement Benefit Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
964,000 
 
 
Fair value of plan assets, end of period
 
964,000 
 
 
Cash and Money Market Funds [Member] |
Other Postretirement Benefit Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
5,894,000 
 
 
Fair value of plan assets, end of period
 
5,894,000 
 
 
Cash and Money Market Funds [Member] |
Other Postretirement Benefit Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Government Obligations [Member] |
Pension Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
47,769,000 
 
 
Fair value of plan assets, end of period
 
47,769,000 
 
 
Government Obligations [Member] |
Pension Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Government Obligations [Member] |
Pension Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
47,769,000 
 
 
Fair value of plan assets, end of period
 
47,769,000 
 
 
Government Obligations [Member] |
Pension Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Government Obligations [Member] |
Other Postretirement Benefit Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
78,000 
 
 
Fair value of plan assets, end of period
 
78,000 
 
 
Government Obligations [Member] |
Other Postretirement Benefit Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Government Obligations [Member] |
Other Postretirement Benefit Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
78,000 
 
 
Fair value of plan assets, end of period
 
78,000 
 
 
Government Obligations [Member] |
Other Postretirement Benefit Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Corporate Obligations [Member] |
Pension Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
153,412,000 
 
 
Fair value of plan assets, end of period
 
153,412,000 
 
 
Corporate Obligations [Member] |
Pension Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Corporate Obligations [Member] |
Pension Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
153,412,000 
 
 
Fair value of plan assets, end of period
 
153,412,000 
 
 
Corporate Obligations [Member] |
Pension Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Corporate Obligations [Member] |
Other Postretirement Benefit Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
251,000 
 
 
Fair value of plan assets, end of period
 
251,000 
 
 
Corporate Obligations [Member] |
Other Postretirement Benefit Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Corporate Obligations [Member] |
Other Postretirement Benefit Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
251,000 
 
 
Fair value of plan assets, end of period
 
251,000 
 
 
Corporate Obligations [Member] |
Other Postretirement Benefit Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Insurance contracts and group annuity contracts [Member] |
Pension Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
59,877,000 
 
 
Fair value of plan assets, end of period
 
59,877,000 
 
 
Level 3 fair value measurement, January 1
63,454,000 
63,454,000 
 
 
Net realized and unrealized gains (losses)
 
3,446,000 
 
 
Settlements
 
(7,023,000)
 
 
Level 3 fair value measurement, December 31
 
59,877,000 
 
 
Insurance contracts and group annuity contracts [Member] |
Pension Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Insurance contracts and group annuity contracts [Member] |
Pension Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Insurance contracts and group annuity contracts [Member] |
Pension Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
59,877,000 
 
 
Fair value of plan assets, end of period
 
59,877,000 
 
 
Insurance contracts and group annuity contracts [Member] |
Other Postretirement Benefit Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
82,353,000 
 
 
Fair value of plan assets, end of period
 
82,353,000 
 
 
Insurance contracts and group annuity contracts [Member] |
Other Postretirement Benefit Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Insurance contracts and group annuity contracts [Member] |
Other Postretirement Benefit Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
82,353,000 
 
 
Fair value of plan assets, end of period
 
82,353,000 
 
 
Insurance contracts and group annuity contracts [Member] |
Other Postretirement Benefit Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Other Investments [Member] |
Pension Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
57,914,000 
 
 
Fair value of plan assets, end of period
 
57,914,000 
 
 
Level 3 fair value measurement, January 1
73,590,000 
73,590,000 
 
 
Net realized and unrealized gains (losses)
 
(15,676,000)
 
 
Settlements
 
0 
 
 
Level 3 fair value measurement, December 31
 
57,914,000 
 
 
Other Investments [Member] |
Pension Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Other Investments [Member] |
Pension Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Other Investments [Member] |
Pension Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
57,914,000 
 
 
Fair value of plan assets, end of period
 
57,914,000 
 
 
Other Investments [Member] |
Other Postretirement Benefit Plan [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
95,000 
 
 
Fair value of plan assets, end of period
 
95,000 
 
 
Other Investments [Member] |
Other Postretirement Benefit Plan [Member] |
Level 1 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Other Investments [Member] |
Other Postretirement Benefit Plan [Member] |
Level 2 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
0 
 
 
Fair value of plan assets, end of period
 
0 
 
 
Other Investments [Member] |
Other Postretirement Benefit Plan [Member] |
Level 3 [Member]
 
 
 
 
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
 
 
 
 
Fair value of plan assets
 
95,000 
 
 
Fair value of plan assets, end of period
 
$ 95,000 
 
 
INCOME TAXES (Details) (USD $)
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Operating loss carryforwards, expiration starting date
Dec. 31, 2035 
 
 
Income taxes receivable
$ 43,800,000 
$ 0 
 
Income taxes payable
0 
0 
 
Cash settlement from ONEOK
3,800,000 
 
 
Net operating loss
8,100,000 
 
 
Current income tax provision (benefit)
 
 
 
Federal
17,006,000 
0 
0 
State
1,397,000 
67,000 
360,000 
Total current income tax provision (benefit)
18,403,000 
67,000 
360,000 
Deferred income tax provision
 
 
 
Federal
42,024,000 
53,562,000 
51,481,000 
State
7,911,000 
8,643,000 
8,010,000 
Total deferred income tax provision
49,935,000 
62,205,000 
59,491,000 
Income Tax Reconciliation [Abstract]
 
 
 
Income before income taxes
178,128,000 
161,467,000 
156,360,000 
Federal statutory income tax rate
35.00% 
35.00% 
35.00% 
Provision for federal income taxes
62,345,000 
56,513,000 
54,726,000 
State income taxes, net of federal benefit
6,051,000 
5,661,000 
5,423,000 
Other, net
(58,000)
98,000 
(298,000)
Income tax provision
68,338,000 
62,272,000 
59,851,000 
Deferred tax assets
 
 
 
Deferred tax assets, employee benefits and other accrued liabilities
128,715,000 
0 
 
Net operating loss
8,144,000 
40,125,000 
 
Other
5,655,000 
8,249,000 
 
Total deferred tax assets
142,514,000 
48,374,000 
 
Deferred tax liabilities
 
 
 
Excess of tax over book depreciation
820,853,000 
750,305,000 
 
Purchased-gas cost adjustment
16,177,000 
4,695,000 
 
Other regulatory assets and liabilities, net
193,159,000 
2,563,000 
 
Total deferred tax liabilities
1,030,189,000 
757,563,000 
 
Net deferred tax liabilities
$ 887,675,000 
$ 709,189,000 
 
COMMITMENTS AND CONTINGENCIES - Part 1 (Details) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Operating Leased Assets [Line Items]
 
 
 
Operating Leases, Rent Expense
$ 5.0 
$ 4.8 
$ 4.8 
Operating Leases, Future Minimum Payments Due [Abstract]
 
 
 
2015
4.7 
 
 
2016
4.5 
 
 
2017
4.3 
 
 
2018
4.0 
 
 
2019
3.4 
 
 
Thereafter
10.4 
 
 
Total
$ 31.3 
 
 
COMMITMENTS AND CONTINGENCIES - Part 2 (Details)
Dec. 31, 2014
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 Soil Remediation Is Completed Or Near Completion
11 
Number of sites where regulatory closure has been achieved
3 
Percentage yield of high consequence pipeline areas
30.00% 
QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) (USD $)
In Thousands, except Per Share data, unless otherwise specified
3 Months Ended 12 Months Ended
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Schedule of Quarterly Financial Information [Line Items]
 
 
 
 
 
 
 
 
 
 
 
Revenues
$ 514,368 
$ 241,522 
$ 296,838 
$ 766,178 
$ 522,686 
$ 219,725 
$ 311,608 
$ 635,933 
$ 1,818,906 
$ 1,689,952 
$ 1,376,649 
Net margin
224,176 
166,452 
176,493 
259,836 
223,654 
159,233 
178,447 
251,674 
826,957 
813,008 
756,389 
Operating income
70,010 
19,119 
26,812 
109,353 
65,014 
14,189 
39,307 
101,838 
225,294 
220,348 
215,714 
Net income
$ 36,607 
$ 4,653 
$ 9,454 
$ 59,076 
$ 30,318 
$ 434 
$ 14,951 
$ 53,492 
$ 109,790 
$ 99,195 
$ 96,509 
Basic
$ 0.70 
$ 0.09 
$ 0.18 
$ 1.13 
 
 
 
 
$ 2.10 
$ 1.90 
$ 1.84 
Diluted
$ 0.69 
$ 0.09 
$ 0.18 
$ 1.13 
 
 
 
 
$ 2.07 
$ 1.90 
$ 1.84 
Basic and Diluted
 
 
 
 
$ 0.58 
$ 0.01 
$ 0.29 
$ 1.02