ONEOK (OKE) 10-Q 6 May 15 2015 Q1 Quarterly report Financial data

Document_And_Entity_Informatio

Document And Entity Information	3 Months Ended
	Mar. 31, 2015	Apr. 27, 2015
Document Information [Line Items]
Entity Registrant Name	ONEOK INC /NEW/
Entity Central Index Key	1039684
Current Fiscal Year End Date	-19
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		208,760,251
Document Fiscal Year Focus	2015
Document Fiscal Period Focus	Q1
Document Type	10-Q
Amendment Flag	FALSE
Document Period End Date	31-Mar-15

CONSOLIDATED_STATEMENTS_OF_INC

CONSOLIDATED STATEMENTS OF INCOME (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Revenues
Commodity sales	$1,435,716	$2,806,729
Services	369,590	356,567
Total revenues	1,805,306	3,163,296
Cost of sales and fuel	1,343,864	2,652,669
Net margin	461,442	510,627
Operating expenses
Operations and maintenance	154,331	126,726
Depreciation and amortization	85,955	67,414
General taxes	24,687	22,385
Total operating expenses	264,973	216,525
Gain (loss) on sale of assets	-6	15
Operating income	196,463	294,117
Equity in net earnings from investments (Note K)	30,921	33,659
Allowance for equity funds used during construction	799	10,971
Other income	3,136	1,409
Other expense	-1,304	-25,534
Interest expense (net of capitalized interest of $7,230 and $15,768, respectively)	-96,750	-94,901
Income before income taxes	133,265	219,721
Income taxes	-37,428	-14,984
Income from continuing operations	95,837	204,737
Income (loss) from discontinued operations, net of tax (Note B)	-144	1,774
Net income	95,693	206,511
Less: Net income attributable to noncontrolling interests	34,893	112,996
Net income attributable to ONEOK	60,800	93,515
Amounts attributable to ONEOK:
Income from continuing operations	60,944	91,741
Income (loss) from discontinued operations	-144	1,774
Net income attributable to ONEOK	$60,800	$93,515
Basic earnings per share:
Income from continuing operations (Note I)	$0.29	$0.44
Income (loss) from discontinued operations	$0	$0.01
Net income	$0.29	$0.45
Diluted earnings per share:
Income from continuing operations (Note I)	$0.29	$0.44
Income (loss) from discontinued operations	$0	$0.01
Net income	$0.29	$0.45
Average shares (thousands)
Basic	209,874	209,130
Diluted	210,467	210,166
Dividends declared per share of common stock	$0.61	$0.40

CONSOLIDATED_STATEMENTS_OF_INC1

CONSOLIDATED STATEMENTS OF INCOME (Parenthetical) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Interest Costs, Capitalized During Period	$7,230	$15,768

CONSOLIDATED_STATEMENTS_OF_COM

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net income	$95,693	$206,511
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on energy marketing and risk-management assets/liabilities, net of tax of $1,679 and $10,228, respectively	-10,878	-49,926
Realized (gains) losses in net income, net of tax of $1,225 and $(13,017), respectively	-9,230	37,527
Unrealized holding gains (losses) on available-for-sale securities, net of tax of $648 and $12, respectively	-955	-76
Change in pension and postretirement benefit plan liability, net of tax of $(1,599) and $(2,567), respectively	2,438	3,851
Total other comprehensive income (loss), net of tax	-18,625	-8,624
Comprehensive income	77,068	197,887
Less: Comprehensive income attributable to noncontrolling interest	19,807	95,687
Comprehensive income attributable to ONEOK	$57,261	$102,200

CONSOLIDATED_STATEMENTS_OF_COM1

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME Parenthetical (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on energy marketing and risk-management assets/liabilities, tax	$1,679	$10,228
Realized losses (gains) in net income, tax	1,225	-13,017
Unrealized holding gains (losses) on available-for-sale securities, tax	648	12
Change in pension and postretirement benefit plan liability, tax	($1,599)	($2,567)

CONSOLIDATED_BALANCE_SHEETS

CONSOLIDATED BALANCE SHEETS (USD $)	Mar. 31, 2015	Dec. 31, 2014
In Thousands, unless otherwise specified
Current assets
Cash and cash equivalents	$239,411	$172,812
Accounts receivable, net	628,064	745,494
Natural gas and natural gas liquids in storage	218,691	134,134
Commodity imbalances	39,667	64,788
Other current assets	175,425	173,299
Assets of discontinued operations (Note B)	20,691	16,717
Total current assets	1,321,949	1,307,244
Property, plant and equipment
Property, plant and equipment	13,908,362	13,602,647
Accumulated depreciation and amortization	2,017,041	1,940,210
Net property, plant and equipment	11,891,321	11,662,437
Investments and other assets
Investments in unconsolidated affiliates	1,124,204	1,132,653
Goodwill and intangible assets	1,011,765	1,014,740
Other assets	167,724	167,466
Assets of discontinued operations (Note B)	16,110	20,020
Total investments and other assets	2,319,803	2,334,879
Total assets	15,533,073	15,304,560
Current liabilities
Current maturities of long-term debt	660,650	10,650
Notes payable (Note E)	825,475	1,055,296
Accounts payable	721,535	891,413
Commodity imbalances	94,586	104,650
Other current liabilities	208,211	285,435
Liabilities of discontinued operations (Note B)	38,263	44,901
Total current liabilities	2,548,720	2,392,345
Long-term debt, excluding current maturities (Note F)	7,339,766	7,192,929
Deferred credits and other liabilities
Deferred income taxes	1,430,478	1,395,222
Other deferred credits	290,422	281,757
Liabilities of discontinued operations (Note B)	30,399	36,424
Total deferred credits and other liabilities	1,751,299	1,713,403
Commitments and contingencies (Note M)
ONEOK shareholders' equity:
Common stock, $0.01 par value: authorized 600,000,000 shares; issued 245,811,180 shares and outstanding 208,760,251 shares at March 31, 2015; issued 245,811,180 shares and outstanding 208,322,247 shares at December 31, 2014	2,458	2,458
Paid-in capital	1,537,166	1,541,583
Accumulated other comprehensive loss (Note H)	-139,892	-136,353
Retained earnings	72,976	138,128
Treasury stock, at cost: 37,050,929 shares at March 31, 2015, and 37,488,933 shares at December 31, 2014	-942,550	-953,701
Total ONEOK shareholders' equity	530,158	592,115
Noncontrolling interests in consolidated subsidiaries	3,363,130	3,413,768
Total equity	3,893,288	4,005,883
Total liabilities and equity	$15,533,073	$15,304,560

CONSOLIDATED_BALANCE_SHEETS_Pa

CONSOLIDATED BALANCE SHEETS Parenthetical (USD $)	Mar. 31, 2015	Dec. 31, 2014
Statement of Financial Position [Abstract]
Common stock, shares, par value (in dollars per share)	$0.01	$0.01
Common stock, shares, authorized (in shares)	600,000,000	600,000,000
Common stock, shares, issued (in shares)	245,811,180	245,811,180
Common stock, shares, outstanding (in shares)	208,760,251	208,322,247
Treasury stock, shares (in shares)	37,050,929	37,488,933

CONSOLIDATED_STATEMENTS_OF_CAS

CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Operating Activities
Net income	$95,693	$206,511
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	85,955	78,768
Charges attributable to exit activities	0	1,739
Equity in net earnings from investments	-30,921	-33,659
Distributions received from unconsolidated affiliates	29,475	30,345
Deferred income taxes	36,712	16,301
Share-based compensation expense	5,643	4,450
Pension and postretirement benefit expense, net of contributions	4,310	8,502
Allowance for equity funds used during construction	-799	-10,971
Loss (gain) on sale of assets	6	-15
Changes in assets and liabilities:
Accounts receivable	134,300	112,780
Natural gas and natural gas liquids in storage	-84,557	63,844
Accounts payable	-125,898	27,817
Commodity imbalances, net	15,057	3,555
Settlement of exit activities liabilities	-12,768	-12,176
Energy marketing and risk management assets and liabilities	-60,871	10,766
Other assets and liabilities, net	-52,067	-18,174
Cash provided by operating activities	39,270	490,383
Investing Activities
Capital expenditures (less allowance for equity funds used during construction)	-343,847	-429,525
Cash paid for acquisitions	0	-14,000
Contributions to unconsolidated affiliates	0	-627
Distributions received from unconsolidated affiliates in excess of cumulative earnings	9,954	4,725
Proceeds from sale of assets	118	93
Cash used in investing activities	-333,775	-439,334
Financing Activities
Borrowing (repayment) of notes payable, net	-229,821	-439,462
Issuance of ONE Gas debt, net of discounts	0	1,199,994
Issuance of long-term debt, net of discounts	798,896	0
ONE Gas long-term debt financing costs	0	-9,663
Debt financing costs	-7,850	0
Repayment of long-term debt	-1,948	-551,933
Issuance of common stock	3,796	3,020
Issuance of common units, net of issuance costs	53,388	52,839
Dividends paid	-126,053	-83,275
Cash of ONE Gas at separation	0	-60,000
Distributions to noncontrolling interests	-129,457	-101,655
Cash provided by financing activities	360,951	9,865
Change in cash and cash equivalents	66,446	60,914
Change in cash and cash equivalents included in discontinued operations	153	3,748
Change in cash and cash equivalents included in continuing operations	66,599	64,662
Cash and cash equivalents at beginning of period	172,812	145,565
Cash and cash equivalents at end of period	$239,411	$210,227

CONSOLIDATED_STATEMENT_OF_CHAN

CONSOLIDATED STATEMENT OF CHANGES IN EQUITY (USD $)	Total	Common Stock [Member]	Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Noncontrolling Interests in Consolidated Subsidiaries [Member]
In Thousands, except Share data
Stockholders' equity, beginning balance at Dec. 31, 2013	$4,845,180						$2,507,329
Net income	206,511						112,996
Other comprehensive income (loss) (Note H)	-8,624						-17,309
Common stock issued	7,579						0
Common stock dividends - $0.605 per share (Note G)	-83,275						0
Issuance of common units of ONEOK Partners (Note L)	52,842						41,846
Distributions to noncontrolling interests	-101,655						-101,655
Other	-43,427						0
Stockholders' equity, ending balance at Mar. 31, 2014	3,127,707						2,543,207
Stockholders' equity, beginning balance at Dec. 31, 2014	4,005,883	2,458	1,541,583	-136,353	138,128	-953,701	3,413,768
Common stock issued, beginning balance (in shares) at Dec. 31, 2014		245,811,180
Net income	95,693	0	0	0	60,800	0	34,893
Other comprehensive income (loss) (Note H)	-18,625	0	0	-3,539	0	0	-15,086
Common stock issued	3,800	0	-7,351	0	0	11,151	0
Common stock issued (in shares)		0
Common stock dividends - $0.605 per share (Note G)	-126,053	0	0	0	-126,053	0	0
Issuance of common units of ONEOK Partners (Note L)	66,273	0	7,261	0	0	0	59,012
Distributions to noncontrolling interests	-129,457	0	0	0	0	0	-129,457
Other	-4,226	0	-4,327	0	101	0	0
Stockholders' equity, ending balance at Mar. 31, 2015	$3,893,288	$2,458	$1,537,166	($139,892)	$72,976	($942,550)	$3,363,130
Common stock issued, ending balance (in shares) at Mar. 31, 2015		245,811,180

CONSOLIDATED_STATEMENT_OF_CHAN1

CONSOLIDATED STATEMENT OF CHANGES IN EQUITY Parenthetical (USD $)	3 Months Ended
	Mar. 31, 2015
Statement of Stockholders' Equity [Abstract]
Common Stock, Dividends, Per Share, Cash Paid	$0.61

SUMMARY_OF_SIGNIFICANT_ACCOUNT

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Summary of Significant Accounting Policies
	A.	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES
	Our accompanying unaudited consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC. These statements have been prepared in accordance with GAAP and reflect all adjustments that, in our opinion, are necessary for a fair presentation of the results for the interim periods presented.  All such adjustments are of a normal recurring nature. The 2014 year-end consolidated balance sheet data was derived from our audited financial statements but does not include all disclosures required by GAAP.  These unaudited consolidated financial statements should be read in conjunction with our audited consolidated financial statements in our Annual Report.
	Our significant accounting policies are consistent with those disclosed in Note A of the Notes to Consolidated Financial Statements in our Annual Report.
	Organization and Nature of Operations - We are the sole general partner and own limited partner units of ONEOK Partners (NYSE: OKS), which together represent an aggregate 37.6 percent interest in ONEOK Partners at March 31, 2015. The results of operations for our former natural gas distribution and energy services businesses have been classified as discontinued operations for all periods presented. See Note B for additional information.
	Unless indicated otherwise, the information in the Notes to the Consolidated Financial Statements relates to our continuing operations.
	Recently Issued Accounting Standards Update - In March 2015, the FASB issued ASU 2015-03, “Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs,” which requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. This guidance is effective for public companies for fiscal years beginning after December 15, 2015, and must be retroactively applied. Early adoption is permitted. We plan to adopt this guidance beginning in the first quarter 2016, and we are evaluating the impact on us.
	In February 2015, the FASB issued ASU 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis,” which eliminates the presumption that a general partner should consolidate a limited partnership. It also modifies the evaluation of whether limited partnerships are variable interest entities or voting interest entities and adds requirements that limited partnerships must meet to qualify as voting interest entities. This guidance is effective for public companies for fiscal years beginning after December 15, 2015. We will adopt this guidance in the first quarter 2016, and we are evaluating the impact on us.
	In August 2014, the FASB issued ASU 2014-15, “Going Concern,” which provides guidance on determining when and how to disclose going-concern uncertainties in the financial statements. The new standard requires management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date the financial statements are issued. An entity must provide certain disclosures if conditions or events raise substantial doubt about the entity’s ability to continue as a going concern. The standard applies to all entities and is effective for annual periods ending after December 15, 2016, and interim periods thereafter, with early adoption permitted. We will adopt this guidance beginning in the first quarter 2016, and we do not expect it to materially impact us.
	In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers,” which outlines the principles an entity must apply to measure and recognize revenue for entities that enter into contracts to provide goods or services to their customers. The core principle is that an entity should recognize revenue at an amount that reflects the consideration to which the entity expects to be entitled in exchange for transferring goods or services to a customer. The amendment also requires more extensive disaggregated revenue disclosures in interim and annual financial statements. This update is effective for interim and annual periods that begin after December 15, 2016, with either retrospective application for all periods presented or retrospective application with a cumulative effect adjustment. In April 2015, the FASB tentatively deferred the effective date by one year with a final determination to be made after a 30-day comment period. We will adopt this guidance beginning in the first quarter 2017, unless the guidance is deferred, and we are evaluating the impact on us.
	In April 2014, the FASB issued ASU 2014-08, “Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity,” which alters the definition of a discontinued operation to include only asset disposals that represent a strategic shift with a major effect on an entity's operations and financial results.  The amendment also requires more extensive disclosures about a discontinued operation’s assets, liabilities, income, expenses and cash flows. This guidance will be effective for interim and annual periods for all assets that are disposed of or classified as being held for sale in fiscal years that begin on or after December 15, 2014. We adopted this guidance beginning in the first quarter 2015, and it could impact us in the future if we dispose of any individually significant components.

DISCONTINUED_OPERATIONS

DISCONTINUED OPERATIONS	3 Months Ended
	Mar. 31, 2015
Discontinued Operations [Abstract]
DISCONTINUED OPERATIONS
	B.	DISCONTINUED OPERATIONS
	Separation of ONE Gas - On January 31, 2014, we completed the separation of ONE Gas, which consists of our former natural gas distribution business. ONEOK shareholders of record at the close of business on January 21, 2014, retained their shares of ONEOK stock and received one share of ONE Gas stock for every four shares of ONEOK stock owned in a transaction that was tax-free to ONEOK and its shareholders. We retained no ownership interest in ONE Gas. Excluding cash of ONE Gas at separation, the separation was accounted for as a noncash activity.
	Wind Down of Energy Services Business - On March 31, 2014, we completed the wind down of our former energy services business. We executed agreements in 2013 and the first quarter 2014 to release a significant portion of our nonaffiliated natural gas transportation and storage contracts to third parties that resulted in noncash charges which are included in income (loss) from discontinued operations, net of tax in our Consolidated Statements of Income.
	The following table summarizes the change in our liability related to released capacity contracts for the periods indicated:
			Three Months Ended
			March 31,
			2015				2014
			(Millions of dollars)
	Beginning balance		$	73.8			$	122
	Noncash charges		—				1.7
	Settlements		(12.8		)		(12.8		)
	Accretion		0.3				0.6
	Ending balance		$	61.3			$	111.5
	We expect future cash payments associated with released transportation and storage capacity contracts from the wind down of our former energy services business to total approximately $37 million on an after-tax basis, which consists of approximately $15 million to be paid in the remainder of 2015, $11 million in 2016, $6 million in 2017 and $5 million over the period 2018 through 2023.
	Results of Operations of Discontinued Operations - The results of operations for our former natural gas distribution business and energy services business have been reported as discontinued operations for all periods presented. Income (loss) from discontinued operations, net of tax, in the Consolidated Statements of Income for the three months ended March 31, 2015, consists of accretion expense, net of tax benefit, on the released contracts for our former energy services business. The table below provides selected financial information reported in discontinued operations in the Consolidated Statements of Income for the three months ended March, 31, 2014:
			Three Months Ended
			31-Mar-14
			Natural Gas				Energy			Total
			Distribution				Services
			(Thousands of dollars)
	Revenues		$	287,249			$	353,404		$	640,653
	Cost of sales and fuel		190,893				364,648			555,541
	Net margin		96,356				(11,244		)	85,112
	Operating costs		59,431			(a)	3,127			62,558
	Depreciation and amortization		11,035				319			11,354
	Operating income (loss)		25,890				(14,690		)	11,200
	Other income (expense), net		(888		)		(7		)	(895		)
	Interest expense, net		(4,592		)		(413		)	(5,005		)
	Income taxes		(10,670		)		7,144			(3,526		)
	Income (loss) from discontinued operations, net		$	9,740			$	(7,966	)	$	1,774
	(a) - Includes approximately $21.7 million for the three months ended March 31, 2014, of costs related to ONE Gas separation.
	Prior to the ONE Gas separation, natural gas sales and transportation and storage services provided to our former natural gas distribution business by ONEOK Partners were $7.5 million for the three months ended March 31, 2014. Prior to February 1, 2014, these revenues and related costs were eliminated in consolidation. Beginning February 1, 2014, these revenues represent third-party transactions with ONE Gas and are not eliminated in consolidation for all periods presented, as such sales and services have continued subsequent to the separation and are expected to continue in future periods.
	Prior to the completion of the energy services wind down, natural gas sales and transportation and storage services provided to our energy services business by ONEOK Partners were $46.0 million for the three months ended March 31, 2014. While these transactions were eliminated in consolidation in previous periods, they are reflected now as affiliate transactions and are not eliminated in consolidation for all periods presented as these transactions have continued with third parties.
	Statement of Financial Position of Discontinued Operations - At March 31, 2015, and December 31, 2014, assets and liabilities of discontinued operations in our Consolidated Balance Sheets relate primarily to deferred tax assets and capacity release obligations associated with our former energy services business.

FAIR_VALUE_MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS
	C.	FAIR VALUE MEASUREMENTS
	Determining Fair Value - We define fair value as the price that would be received from the sale of an asset or the transfer of a liability in an orderly transaction between market participants at the measurement date.  We use 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.
	While many of the contracts in ONEOK Partners’ portfolio are executed in liquid markets where price transparency exists, some contracts are executed in markets for which market prices may exist, but the market may be relatively inactive.  This results in limited price transparency that requires management’s judgment and assumptions to estimate fair values.  For certain transactions, we utilize modeling techniques using NYMEX-settled pricing data and implied forward LIBOR curves. Inputs into our fair value estimates include commodity-exchange prices, over-the-counter quotes, historical correlations of pricing data and LIBOR and other liquid money-market instrument rates.  We also utilize internally developed basis curves that incorporate observable and unobservable market data.  We validate our valuation inputs with third-party information and settlement prices from other sources, where available.
	In addition, as prescribed by the income approach, we compute the fair value of our and ONEOK Partners’ derivative portfolios by discounting the projected future cash flows from our derivative assets and liabilities to present value using interest-rate yields to calculate present-value discount factors derived from LIBOR, Eurodollar futures and interest-rate swaps.  We also take into consideration the potential impact on market prices of liquidating positions in an orderly manner over a reasonable period of time under current market conditions.  We consider current market data in evaluating counterparties’, as well as our own, nonperformance risk, net of collateral, by using specific and sector bond yields and monitoring the credit default swap markets.  Although we use our best estimates to determine the fair value of the derivative contracts we and ONEOK Partners have executed, the ultimate market prices realized could differ from our estimates, and the differences could be material.
	The fair value of our forward-starting interest-rate swaps are determined using financial models that incorporate the implied forward LIBOR yield curve for the same period as the future interest swap settlements.
	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 - fair value measurements are based on unadjusted quoted prices for identical securities in active markets, including NYMEX-settled prices. These balances are comprised predominantly of exchange-traded derivative contracts for natural gas and crude oil.
	•	Level 2 - fair value measurements are based on significant observable pricing inputs, such as NYMEX-settled prices for natural gas and crude oil, and financial models that utilize implied forward LIBOR yield curves for interest-rate swaps.
	•	Level 3 - fair value measurements are based on inputs that may include one or more unobservable inputs, including internally developed basis curves that incorporate observable and unobservable market data, NGL price curves from broker quotes, market volatilities derived from the most recent NYMEX close spot prices and forward LIBOR curves, and adjustments for the credit risk of our counterparties.  We corroborate the data on which our fair value estimates are based using our market knowledge of recent transactions, analysis of historical correlations and validation with independent broker quotes.  These balances categorized as Level 3 are comprised of derivatives for natural gas and NGLs.  We do not believe that our Level 3 fair value estimates have a material impact on our results of operations, as the majority of our derivatives are accounted for as hedges for which ineffectiveness is not material.
	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.
	Recurring Fair Value Measurements - The following tables set forth our recurring fair value measurements for our continuing operations for the periods indicated:
		March 31, 2015
		Level 1			Level 2			Level 3			Total - Gross			Netting (a)			Total - Net (b)
		(Thousands of dollars)
	Derivative assets
	Commodity contracts
	Financial contracts	$	38,445		$	—		$	3,183		$	41,628		$	(18,224	)	$	23,404
	Physical contracts	—			—			7,395			7,395			—			7,395
	Total derivative assets	$	38,445		$	—		$	10,578		$	49,023		$	(18,224	)	$	30,799
	Derivative liabilities
	Commodity contracts
	Financial contracts	$	(231	)	$	—		$	(3,538	)	$	(3,769	)	$	3,769		$	—
	Interest-rate contracts	—			(9,947		)	—			(9,947		)	—			(9,947		)
	Total derivative liabilities	$	(231	)	$	(9,947	)	$	(3,538	)	$	(13,716	)	$	3,769		$	(9,947	)
	(a) - Derivative assets and liabilities are presented in our Consolidated Balance Sheets on a net basis.  We net derivative assets and liabilities when a legally enforceable master-netting arrangement exists between the counterparty to a derivative contract and ONEOK Partners.  At March 31, 2015, ONEOK Partners had $14.5 million of cash held from various counterparties and posted no cash collateral.
	(b) - Included in other current assets or deferred credits and other liabilities in our Consolidated Balance Sheets.
		December 31, 2014
		Level 1			Level 2			Level 3			Total - Gross			Netting (a)			Total - Net (b)
		(Thousands of dollars)
	Assets
	Derivatives
	Commodity contracts
	Financial contracts	$	42,880		$	—		$	354		$	43,234		$	(25,979	)	$	17,255
	Physical contracts	—			—			9,922			9,922			—			9,922
	Interest-rate contracts	—			2,288			—			2,288			—			2,288
	Total derivative assets	42,880			2,288			10,276			55,444			(25,979		)	29,465
	Available-for-sale investment securities	1,773			—			—			1,773			—			1,773
	Total assets	$	44,653		$	2,288		$	10,276		$	57,217		$	(25,979	)	$	31,238
	Liabilities
	Derivatives
	Commodity contracts
	Financial contracts	$	(169	)	$	—		$	(968	)	$	(1,137	)	$	1,137		$	—
	Physical contracts	—			—			(23		)	(23		)	—			(23		)
	Interest-rate contracts	—			(44,843		)	—			(44,843		)	—			(44,843		)
	Total derivative liabilities	$	(169	)	$	(44,843	)	$	(991	)	$	(46,003	)	$	1,137		$	(44,866	)
	(a) - Derivative assets and liabilities are presented in our Consolidated Balance Sheets on a net basis. We net derivative assets and liabilities when a legally enforceable master-netting arrangement exists between the counterparty to a derivative contract and ONEOK Partners. At December 31, 2014, ONEOK Partners had $24.8 million of cash held from various counterparties and posted no cash collateral.
	(b) - Included in other current assets, other assets or other current liabilities in our Consolidated Balance Sheets.
	The following table sets forth a reconciliation of our Level 3 fair value measurements for our continuing operations for the periods indicated:
		Three Months Ended
		March 31,
	Derivative Assets (Liabilities)	2015			2014
		(Thousands of dollars)
	Net assets (liabilities) at beginning of period	$	9,285		$	(782	)
	Total realized/unrealized gains (losses):
	Included in earnings (a)	269			(928		)
	Included in other comprehensive income (loss)	(2,514		)	(52		)
	Purchases, issuances and settlements	—			3,734
	Net assets (liabilities) at end of period	$	7,040		$	1,972
	(a) - Included in commodity sales revenues in our Consolidated Statements of Income.
	Realized/unrealized gains (losses) include the realization of ONEOK Partners’ derivative contracts through maturity. During the three months ended March 31, 2015 and 2014, gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the end of the period were not material.
	We recognize transfers into and out of the levels in the fair value hierarchy as of the end of each reporting period.  During the three months ended March 31, 2015 and 2014, there were no transfers between levels.
	Other Financial Instruments - The approximate fair value of cash and cash equivalents, accounts receivable, accounts payable and notes 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.  Our notes payable are classified as Level 2 since the estimated fair value of the notes payable can be determined using information available in the commercial paper market.
	The estimated fair value of our consolidated long-term debt, including current maturities, was $8.3 billion and $7.5 billion at March 31, 2015, and December 31, 2014, respectively.  The book value of long-term debt, including current maturities, was $8.0 billion and $7.2 billion at March 31, 2015, and December 31, 2014, respectively.  The estimated fair value of the aggregate of ONEOK’s and ONEOK Partners’ senior notes outstanding was determined using quoted market prices for similar issues with similar terms and maturities.  The estimated fair value of our consolidated long-term debt is classified as Level 2.

RISK_MANAGEMENT_AND_HEDGING_AC

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES
	D.	RISK-MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES
	Risk-Management Activities - ONEOK Partners is sensitive to changes in natural gas, crude oil and NGL prices, principally as a result of contractual terms under which these commodities are processed, purchased and sold.  ONEOK Partners uses physical-forward sales and financial derivatives to secure a certain price for a portion of its natural gas, condensate and NGL products; to reduce its exposure to interest-rate fluctuations; and to achieve more predictable cash flows.  ONEOK Partners follows established policies and procedures to assess risk and approve, monitor and report its risk-management activities. ONEOK Partners has not used these instruments for trading purposes.  We and ONEOK Partners are also subject to the risk of interest-rate fluctuation in the normal course of business.
	Commodity price risk - ONEOK Partners is exposed to the risk of loss in cash flows and future earnings arising from adverse changes in the price of natural gas, NGLs and condensate.  ONEOK Partners uses the following commodity derivative instruments to mitigate the near-term commodity price risk associated with a portion of the forecasted sales of these commodities:
	•	Futures contracts - Standardized contracts to purchase or sell natural gas and crude oil for future delivery or settlement under the provisions of exchange regulations;
	•	Forward contracts - Nonstandardized commitments between two parties to purchase or sell natural gas, crude oil or NGLs for future physical delivery. These contracts are typically nontransferable and can only be canceled with the consent of both parties; and
	•	Swaps - Exchange of one or more payments based on the value of one or more commodities. These instruments transfer the financial risk associated with a future change in value between the counterparties of the transaction, without also conveying ownership interest in the asset or liability.
	ONEOK Partners may also use other instruments including options or collars to mitigate commodity price risk. Options are contractual agreements that give the holder the right, but not the obligation, to buy or sell a fixed quantity of a commodity, at a fixed price, within a specified period of time. Options may either be standardized and exchange traded or customized and nonexchange traded. A collar is a combination of a purchased put option and a sold call option, which places a floor and a ceiling price for commodity sales being hedged.
	The Natural Gas Gathering and Processing segment is exposed to commodity price risk as a result of receiving commodities in exchange for services associated with its POP contracts. ONEOK Partners also is exposed to basis risk between the various production and market locations where it receives and sells commodities.  As part of ONEOK Partners’ hedging strategy, it uses the previously described commodity derivative financial instruments and physical-forward contracts to reduce the impact of price fluctuations related to natural gas, NGLs and condensate.
	The Natural Gas Liquids segment is exposed to location price differential risk primarily as a result of the relative value of NGL purchases at one location and sales at another location. ONEOK Partners is also exposed to commodity price risk resulting from the relative values of the various NGL products to each other, NGLs in storage and the relative value of NGLs to natural gas. ONEOK Partners utilizes physical-forward contracts to reduce the impact of price fluctuations related to NGLs. At March 31, 2015, and December 31, 2014, there were no financial derivative instruments with respect to ONEOK Partners’ natural gas liquids operations.
	The Natural Gas Pipelines segment is exposed to commodity price risk because its intrastate and interstate natural gas pipelines retain natural gas from its customers for operations or as part of its fee for services provided. When the amount of natural gas consumed in operations by these pipelines differs from the amount provided by its customers, ONEOK Partners’ pipelines must buy or sell natural gas, or store or use natural gas from inventory, which can expose it to commodity price risk depending on the regulatory treatment for this activity. To the extent that commodity price risk in the Natural Gas Pipelines segment is not mitigated by fuel cost-recovery mechanisms, ONEOK Partners uses physical-forward sales or purchases to reduce the impact of price fluctuations related to natural gas. At March 31, 2015, and December 31, 2014, there were no financial derivative instruments with respect to ONEOK Partners’ natural gas pipeline operations.
	Interest-rate risk - We and ONEOK Partners manage interest-rate risk through the use of fixed-rate debt, floating-rate debt and interest-rate swaps. Interest-rate swaps are agreements to exchange interest payments at some future point based on specified notional amounts. At December 31, 2014, ONEOK Partners had forward-starting interest-rate swaps with notional amounts totaling $900 million that were designated as cash flow hedges of the variability of interest payments on a portion of forecasted debt issuances that may result from changes in the benchmark interest rate before the debt is issued. Upon ONEOK Partners’ debt issuance in March 2015, it settled $500 million of its interest-rate swaps and realized a loss of $55.1 million, which is included in accumulated other comprehensive loss and will be amortized to interest expense over the term of the related debt. At March 31, 2015, ONEOK Partners’ remaining interest-rate swaps with notional amounts totaling $400 million have settlement dates greater than 12 months.
	Accounting Treatment - We and ONEOK Partners record all derivative instruments at fair value, with the exception of normal purchases and normal sales transactions that are expected to result in physical delivery.  Commodity price and interest-rate volatility may have a significant impact on the fair value of derivative instruments as of a given date. 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.
	The table below summarizes the various ways in which we account for our derivative instruments and the impact on our consolidated financial statements:
			Recognition and Measurement
	Accounting Treatment		Balance Sheet		Income Statement
	Normal purchases and normal	-	Fair value not recorded	-	Change in fair value not recognized in earnings
	sales
	Mark-to-market	-	Recorded at fair value	-	Change in fair value recognized in earnings
	Cash flow hedge	-	Recorded at fair value	-	Ineffective portion of the gain or loss on the
					derivative instrument is recognized in earnings
		-	Effective portion of the gain or loss on the	-	Effective portion of the gain or loss on the
			derivative instrument is reported initially		derivative instrument is reclassified out of
			as a component of accumulated other		accumulated other comprehensive income (loss)
			comprehensive income (loss)		into earnings when the forecasted transaction
					affects earnings
	Fair value hedge	-	Recorded at fair value	-	The gain or loss on the derivative instrument is
					recognized in earnings
		-	Change in fair value of the hedged item is	-	Change in fair value of the hedged item is
			recorded as an adjustment to book value		recognized in earnings
	To reduce its exposure to fluctuations in natural gas, NGLs and condensate prices, ONEOK Partners periodically enters into futures, forward sales, options or swap transactions in order to hedge anticipated purchases and sales of natural gas, NGLs and condensate.  Interest-rate swaps are used from time to time to manage interest-rate risk.  Under certain conditions, we designate these derivative instruments as a hedge of exposure to changes in fair values or cash flows.  We formally document all relationships between hedging instruments and hedged items, as well as risk-management objectives and strategies for undertaking various hedge transactions and methods for assessing and testing correlation and hedge ineffectiveness.  We specifically identify the forecasted transaction that has been designated as the hedged item in a cash flow hedge relationship. We assess the effectiveness of hedging relationships quarterly by performing an effectiveness analysis on our fair value and cash flow hedging relationships to determine whether the hedge relationships are highly effective on a retrospective and prospective basis.  ONEOK Partners also documents its normal purchases and normal sales transactions that are expected to result in physical delivery and that ONEOK Partners elects to exempt from derivative accounting treatment.
	The realized revenues and purchase costs of our and ONEOK Partners’ derivative instruments not considered held for trading purposes and derivatives that qualify as normal purchases or normal sales that are expected to result in physical delivery are reported on a gross basis. Cash flows from futures, forwards and swaps that are accounted for as hedges are included in the same category as the cash flows from the related hedged items in our Consolidated Statements of Cash Flows.
	For the three months ended March 31, 2014, income from discontinued operations in our Consolidated Statements of Income includes revenues from financial trading margins, as well as certain physical natural gas transactions with our trading counterparties. Revenues and cost of sales and fuel from such physical transactions are reported on a net basis. See Note B for disclosures of our discontinued operations.
	Fair Values of Derivative Instruments - See Note C for a discussion of the inputs associated with our fair value measurements. The following table sets forth the fair values of derivative instruments for our continuing operations for the periods indicated:
		March 31, 2015								December 31, 2014
		Assets (a)				(Liabilities) (a)				Assets (a)			(Liabilities) (a)
		(Thousands of dollars)
	Derivatives designated as hedging instruments
	Commodity contracts
	Financial contracts	$	41,053			$	(3,565	)		$	43,234		$	(1,137	)
	Physical contracts	7,395				—				9,922			—
	Interest-rate contracts	—				(9,947		)		2,288			(44,843		)
	Total derivatives designated as hedging instruments	48,448				(13,512		)		55,444			(45,980		)
	Derivatives not designated as hedging instruments
	Commodity contracts
	Financial contracts	575				(204		)		—			—
	Physical contracts	—				—				—			(23		)
	Total derivatives not designated as hedging instruments	575				(204		)		—			(23		)
	Total derivatives	$	49,023			$	(13,716	)		$	55,444		$	(46,003	)
	(a) - Included on a net basis in other current assets or deferred credits and other liabilities in our Consolidated Balance Sheets.
	Notional Quantities for Derivative Instruments - The following table sets forth the notional quantities for derivative instruments for our continuing operations for the periods indicated:
			March 31, 2015								December 31, 2014
		Contract	Purchased/				Sold/				Purchased/			Sold/
		Type	Payor				Receiver				Payor			Receiver
	Derivatives designated as hedging instruments:
	Cash flow hedges
	Fixed price
	- Natural gas (Bcf)	Futures and swaps	—				(45.5		)		—			(41.2		)
	- Crude oil and NGLs (MMBbl)	Futures, forwards	—				(4.1		)		—			(0.5		)
		and swaps
	Basis
	- Natural gas (Bcf)	Futures and swaps	—				(45.5		)		—			(41.2		)
	Interest-rate contracts (Millions of dollars)	Forward-starting	$	400			$	—			$	900		$	—
		swaps
Derivatives not designated as hedging instruments:
Fixed price
- Crude oil and NGLs (MMBbl)	Futures, forwards	0.6				(0.6		)		—			—
	and swaps
These notional amounts are used to summarize the volume of financial instruments; however, they do not reflect the extent to which the positions offset one another and, consequently, do not reflect ONEOK Partners’ actual exposure to market or credit risk.
Cash Flow Hedges - ONEOK Partners uses derivative instruments to hedge the cash flows associated with anticipated purchases and sales of natural gas, NGLs and condensate and cost of fuel used in the transportation of natural gas. Accumulated other comprehensive loss at March 31, 2015, includes gains of approximately $11.5 million, net of tax, related to these hedges that will be recognized within the next 21 months as the forecasted transactions affect earnings.  If prices remain at current levels, we will recognize $11.3 million in net gains over the next 12 months and net gains of $0.2 million thereafter.  The amount deferred in accumulated other comprehensive loss attributable to our and ONEOK Partners’ settled interest-rate swaps is a loss of $50.1 million, net of tax, which will be recognized over the life of the long-term, fixed-rate debt. We expect that losses of $5.8 million, net of tax, will be reclassified into earnings during the next 12 months as the hedged items affect earnings. The remaining amounts in accumulated other comprehensive loss are attributable primarily to ONEOK Partners’ forward-starting interest-rate swaps with future settlement dates, which will be amortized to interest expense over the life of long-term, fixed-rate debt upon issuance of ONEOK Partners’ debt.
The following table sets forth the unrealized effect of cash flow hedges recognized in other comprehensive income (loss) for the periods indicated:
Derivatives in Cash Flow	Three Months Ended
Hedging Relationships	March 31,
	2015				2014
	(Thousands of dollars)
Continuing Operations
Commodity contracts	$	10,019			$	(35,762	)
Interest-rate contracts	(22,576		)		(20,693		)
Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion) for continuing operations	(12,557		)		(56,455		)
Discontinued Operations
Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion) for discontinued operations - commodity contracts	—				(3,697		)
Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion)	$	(12,557	)		$	(60,152	)
The following table sets forth the effect of cash flow hedges in our Consolidated Statements of Income for the periods indicated:
Derivatives in Cash Flow	Location of Gain (Loss) Reclassified from	Three Months Ended
Hedging Relationships	Accumulated Other Comprehensive Income	March 31,
	(Loss) into Net Income (Effective Portion)	2015				2014
		(Thousands of dollars)
Continuing Operations
Commodity contracts	Commodity sales revenues	$	14,172			$	(26,419	)
Interest-rate contracts	Interest expense	(3,717		)		(11,321		)
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income on derivatives (effective portion)		10,455				(37,740		)
Discontinued Operations
Commodity contracts	Income (loss) from discontinued operations -	—				(12,803		)
	Commodity sales revenues
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income from discontinued operations on derivatives (effective portion)		—				(12,803		)
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income on derivatives (effective portion)		$	10,455			$	(50,543	)
Ineffectiveness related to ONEOK Partners’ cash flow hedges was not material for the three months ended March 31, 2015 and 2014.  Ineffectiveness related to our former energy services business’ cash flow hedges was not material for the three months ended March 31, 2014. In the event that it becomes probable that a forecasted transaction will not occur, we would discontinue cash flow hedge treatment, which would affect earnings. For the three months ended March 31, 2015, there were no gains or losses due to the discontinuance of cash flow hedge treatment. For the three months ended March 31, 2014, we reclassified losses of $4.6 million, net of taxes of $3.1 million, to interest expense from accumulated other comprehensive loss due to the discontinuance of cash flow hedge treatment from the de-designation of interest-rate swaps related to the early retirement of long-term debt. See Note F for additional information.
Credit Risk - We and ONEOK Partners monitor the creditworthiness of counterparties and compliance with policies and limits established by our Risk Oversight and Strategy Committee. We and ONEOK Partners maintain credit policies with regard to counterparties that we believe minimize overall credit risk.  These policies include an evaluation of potential counterparties’ financial condition (including credit ratings, bond yields and credit default swap rates), collateral requirements under certain circumstances and the use of standardized master-netting agreements that allow us to net the positive and negative exposures associated with a single counterparty.  ONEOK Partners has counterparties whose credit is not rated, and for those customers, it uses internally developed credit ratings.
Some of ONEOK Partners’ financial derivative instruments contain provisions that require it to maintain an investment-grade credit rating from S&P and/or Moody’s.  If ONEOK Partners’ credit ratings on its senior unsecured long-term debt were to decline below investment grade, the counterparties to the derivative instruments could request collateralization on derivative instruments in net liability positions. There were no financial derivative instruments with contingent features related to credit risk that were in a net liability position at March 31, 2015.
The counterparties to ONEOK Partners’ derivative contracts consist primarily of major energy companies, financial institutions and commercial and industrial end users.  This concentration of counterparties may affect ONEOK Partners’ overall exposure to credit risk, either positively or negatively, in that the counterparties may be affected similarly by changes in economic, regulatory or other conditions.  Based on ONEOK Partners’ policies, exposures, credit and other reserves, we do not anticipate a material adverse effect on our financial position or results of operations as a result of counterparty nonperformance.
At March 31, 2015, the net credit exposure from ONEOK Partners’ derivative assets is primarily with investment-grade companies in the financial services sector.

CREDIT_FACILITIES_AND_SHORTTER

CREDIT FACILITIES AND SHORT-TERM NOTES PAYABLE	3 Months Ended
	Mar. 31, 2015
Short-term Debt [Abstract]
CREDIT FACILITIES AND SHORT-TERM NOTES PAYABLE
	E.	CREDIT FACILITIES AND SHORT-TERM NOTES PAYABLE
	ONEOK Credit Agreement - The ONEOK Credit Agreement, which is scheduled to expire in January 2019, is a $300 million revolving credit facility and contains certain financial, operational and legal covenants. Among other things, these covenants include maintaining a ratio of indebtedness to Consolidated EBITDA (EBITDA, as defined in our ONEOK Credit Agreement) of no more than 4.0 to 1. Upon breach of certain covenants by us in the ONEOK Credit Agreement, amounts outstanding under the ONEOK Credit Agreement, if any, may become due and payable immediately. At March 31, 2015, ONEOK’s ratio of indebtedness to Consolidated EBITDA was 2.2 to 1, and ONEOK was in compliance with all covenants under the ONEOK Credit Agreement. As a result of a reduction in the borrowing capacity of the ONEOK Credit Agreement, we wrote off approximately $2.9 million in interest expense of previously deferred credit agreement issuance costs in the first quarter 2014.
	The ONEOK Credit Agreement also includes a $50 million sublimit for the issuance of standby letters of credit and a $50 million sublimit for swingline loans. Under the terms of the ONEOK Credit Agreement, ONEOK may request an increase in the size of the facility to an aggregate of $500 million from $300 million by either commitments from new lenders or increased commitments from existing lenders. The ONEOK 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 rating, borrowings, if any, will accrue at LIBOR plus 125 basis points, and the annual facility fee is 25 basis points.
	At March 31, 2015, ONEOK had $1.8 million in letters of credit issued and no borrowings under the ONEOK Credit Agreement. In February 2014, we repaid all amounts outstanding under our commercial paper program, with a portion of the proceeds received from ONE Gas in connection with the separation, and terminated the program. See Note F for additional information.
	ONEOK Partners Credit Agreement - The amount of short-term borrowings authorized by ONEOK Partners GP’s Board of Directors is $2.5 billion. At March 31, 2015, ONEOK Partners had $825.5 million of commercial paper outstanding, $14.0 million in letters of credit issued and no borrowings under the ONEOK Partners Credit Agreement.
	The ONEOK Partners Credit Agreement, which is scheduled to expire in January 2019, is a $2.4 billion revolving credit facility and includes a $100 million sublimit for the issuance of standby letters of credit and a $150 million swingline sublimit. The ONEOK Partners Credit Agreement is available for general partnership purposes. During the first quarter 2015, ONEOK Partners increased the size of the ONEOK Partners Credit Agreement to $2.4 billion from $1.7 billion by exercising its option to increase the capacity of the facility through increased commitments from existing lenders and a commitment from one new lender. During the first quarter 2015, ONEOK Partners also increased the size of its commercial paper program to $2.4 billion from $1.7 billion. Amounts outstanding under ONEOK Partners’ commercial paper program reduce the borrowing capacity under the ONEOK Partners Credit Agreement.
	The ONEOK Partners Credit Agreement contains provisions for an applicable margin rate and an annual facility fee, both of which adjust with changes in its credit rating. Under the terms of the ONEOK Partners Credit Agreement, based on ONEOK Partners’ current credit ratings, borrowings, if any, will accrue at LIBOR plus 117.5 basis points, and the annual facility fee is 20 basis points. The ONEOK Partners Credit Agreement is guaranteed fully and unconditionally by the Intermediate Partnership. Borrowings under the ONEOK Partners Credit Agreement are nonrecourse to ONEOK.
	The ONEOK Partners Credit Agreement contains certain financial, operational and legal covenants. Among other things, these covenants include maintaining a ratio of indebtedness to adjusted EBITDA (EBITDA, as defined in the ONEOK Partners Credit Agreement, adjusted for all noncash charges and increased for projected EBITDA from certain lender-approved capital expansion projects) of no more than 5.0 to 1.  If ONEOK Partners consummates one or more acquisitions in which the aggregate purchase price is $25 million or more, the allowable ratio of indebtedness to adjusted EBITDA will increase to 5.5 to 1 for the quarter in which the acquisition was completed and the two following quarters.  As a result of the West Texas LPG acquisition ONEOK Partners completed in the fourth quarter 2014, the allowable ratio of indebtedness to adjusted EBITDA increased to 5.5 to 1 through the second quarter 2015. If ONEOK Partners were to breach certain covenants in the ONEOK Partners Credit Agreement, amounts outstanding under the ONEOK Partners Credit Agreement, if any, may become due and payable immediately.  At March 31, 2015, ONEOK Partners’ ratio of indebtedness to adjusted EBITDA was 4.5 to 1, and it was in compliance with all covenants under the ONEOK Partners Credit Agreement.
	Neither ONEOK nor ONEOK Partners guarantees the debt or other similar commitments of unaffiliated parties. ONEOK does not guarantee the debt, commercial paper or other similar commitments of ONEOK Partners, and ONEOK Partners does not guarantee the debt or other similar commitments of ONEOK.

LONGTERM_DEBT

LONG-TERM DEBT	3 Months Ended
	Mar. 31, 2015
Long-term Debt, Unclassified [Abstract]
LONG-TERM DEBT
	F.	LONG-TERM DEBT
	ONEOK Partners Debt Issuance - In March 2015, ONEOK Partners completed an underwritten public offering of $800 million of senior notes, consisting of $300 million, 3.8 percent senior notes due 2020 and $500 million, 4.9 percent senior notes due 2025. The net proceeds, after deducting underwriting discounts, commissions and offering expenses, were approximately$792.3 million. ONEOK Partners used the proceeds to repay amounts outstanding under its commercial paper program and for general partnership purposes.
	These notes are governed by an indenture, dated as of September 25, 2006, between ONEOK Partners and Wells Fargo Bank, N.A., the trustee, as supplemented. The indenture does not limit the aggregate principal amount of debt securities that may be issued and provides that debt securities may be issued from time to time in one or more additional series. The indenture contains covenants including, among other provisions, limitations on ONEOK Partners’ ability to place liens on its property or assets and to sell and lease back its property. The indenture includes an event of default upon acceleration of other indebtedness of $100 million or more. Such events of default would entitle the trustee or the holders of 25 percent in aggregate principal amount of any of ONEOK Partners’ outstanding senior notes to declare those notes immediately due and payable in full.
	ONEOK Partners may redeem its 3.8 percent senior notes due 2020 and its 4.9 percent senior notes due 2025 from the March 2015 offering at par, plus accrued and unpaid interest to the redemption date, starting one month and three months, respectively, before their maturity dates. Prior to these dates, ONEOK Partners may redeem these 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. ONEOK Partners’ senior notes are senior unsecured obligations, ranking equally in right of payment with all of ONEOK Partners’ existing and future unsecured senior indebtedness, and structurally subordinate to any of the existing and future debt and other liabilities of any ONEOK Partners’ nonguarantor subsidiaries.
	ONEOK Partners Debt Maturity - ONEOK Partners’ $650 million, 3.25 percent senior notes mature on February 1, 2016. The carrying amount of these notes is reflected in current portion of long-term debt in our Consolidated Balance Sheet as of March 31, 2015.
	ONE Gas Debt Issuance - In January 2014, ONE Gas, which at the time was our wholly owned subsidiary, completed a private placement of three series of senior notes aggregating $1.2 billion, consisting of $300 million of five-year senior notes at 2.07 percent; $300 million of 10-year senior notes at 3.61 percent; and $600 million of 30-year senior notes at 4.658 percent. ONE Gas received approximately $1.19 billion from the offering, net of issuance costs. Our obligations related to the ONE Gas Senior Notes terminated in connection with the completion of the separation of ONE Gas.
	ONEOK Debt Repayment - ONE Gas made a cash payment to us of approximately $1.13 billion from the proceeds of the ONE Gas senior notes offering. In February 2014, we retired approximately $152.5 million of the 4.25 percent senior notes due in 2022 through a tender offer. The total amount paid was approximately $150 million.
	In February 2014, we called our $400 million, 5.2 percent senior notes due in 2015. The full repayment occurred in March 2014 and totaled $430.1 million, including accrued but unpaid interest to the redemption date. We recorded a loss on extinguishment of $24.8 million related to the debt retirements, which is included in other expense in our Consolidated Statements of Income.

EQUITY

EQUITY	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Stockholders' Equity Note Disclosure [Text Block]
	G.	EQUITY
	The following table sets forth the changes in equity attributable to us and our noncontrolling interests, including other comprehensive income, net of tax, for the periods indicated:
		Three Months Ended									Three Months Ended
		31-Mar-15									31-Mar-14
		ONEOK			Noncontrolling			Total			ONEOK			Noncontrolling			Total
		Shareholders’			Interests in			Equity			Shareholders’			Interests in			Equity
		Equity			Consolidated						Equity			Consolidated
					Subsidiaries									Subsidiaries
		(Thousands of dollars)
	Beginning balance	$	592,115		$	3,413,768		$	4,005,883		$	2,337,851		$	2,507,329		$	4,845,180
	Net income	60,800			34,893			95,693			93,515			112,996			206,511
	Other comprehensive income	(3,539		)	(15,086		)	(18,625		)	8,685			(17,309		)	(8,624		)
	(loss)
	Common stock issued	3,800			—			3,800			7,579			—			7,579
	Common stock dividends	(126,053		)	—			(126,053		)	(83,275		)	—			(83,275		)
	Issuance of common units of	7,261			59,012			66,273			10,996			41,846			52,842
	ONEOK Partners
	Distribution of ONE Gas to shareholders	—			—			—			(1,747,424		)	—			(1,747,424		)
	Distributions to noncontrolling	—			(129,457		)	(129,457		)	—			(101,655		)	(101,655		)
	interests
	Other	(4,226		)	—			(4,226		)	(43,427		)	—			(43,427		)
	Ending balance	$	530,158		$	3,363,130		$	3,893,288		$	584,500		$	2,543,207		$	3,127,707
	Dividends - Dividends paid on our common stock to shareholders of record at the close of business on January 30, 2015, were $0.605 per share.  A dividend of $0.605 per share was declared for shareholders of record at the close of business on April 30, 2015, payable May 15, 2015.
	See Note L for a discussion of ONEOK Partners’ issuance of common units and distributions to noncontrolling interests.

ACCUMULATED_OTHER_COMPREHENSIV

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	3 Months Ended
	Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
	H.	ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)
	The following table sets forth the balance in accumulated other comprehensive income (loss) for the period indicated:
		Unrealized Gains				Unrealized				Pension and			Accumulated
		(Losses) on Energy				Holding Gains				Postretirement			Other
		Marketing and				(Losses)				Benefit Plan			Comprehensive
		Risk-Management				on Investment				Obligations (a) (b)			Income (Loss) (a)
		Assets/Liabilities (a)				Securities (a)
		(Thousands of dollars)
	1-Jan-15	$	(37,349	)		$	955			$	(99,959	)	$	(136,353	)
	Other comprehensive income (loss) before	(2,864		)		(955		)		19			(3,800		)
	reclassifications
	Amounts reclassified from accumulated other	(2,158		)		—				2,419			261
	comprehensive income (loss)
	Net current period other comprehensive income	(5,022		)		(955		)		2,438			(3,539		)
	(loss) attributable to ONEOK
	March 31, 2015	$	(42,371	)		$	—			$	(97,521	)	$	(139,892	)
	(a) All amounts are presented net of tax.
	(b) Includes amounts related to supplemental executive retirement plan.
	The following table sets forth the effect of reclassifications from accumulated other comprehensive income (loss) in our Consolidated Statements of Income for the periods indicated:
	Details about Accumulated Other		Three Months Ended								Affected Line Item in the
	Comprehensive Income (Loss) Components		March 31,								Consolidated Statements of Income
			2015				2014
			(Thousands of dollars)
	Unrealized (gains) losses on energy marketing and risk-management assets/liabilities
	Commodity contracts		$	(14,172	)		$	26,419			Commodity sales revenues
	Interest-rate contracts		3,717				11,321				Interest expense
			(10,455		)		37,740				Income before income taxes
			1,225				(7,896		)		Income tax expense
			(9,230		)		29,844				Income from continuing operations
			—				7,683				Income (loss) from discontinued operations
			(9,230		)		37,527				Net income
	Noncontrolling interest		(7,072		)		17,109				Less: Net income attributable to noncontrolling interest
			$	(2,158	)		$	20,418			Net income (loss) attributable to ONEOK
	Pension and postretirement benefit plan obligations (a)
	Amortization of net loss		$	4,423			$	3,963
	Amortization of unrecognized prior service cost		(392		)		(367		)
			4,031				3,596				Income before income taxes
			(1,612		)		(1,438		)		Income tax expense
			2,419				2,158				Income from continuing operations
			—				1,648				Income from discontinued operations
			$	2,419			$	3,806			Net income attributable to ONEOK
	Total reclassifications for the period attributable to ONEOK		$	261			$	24,224			Net income attributable to ONEOK
	(a) These components of accumulated other comprehensive income (loss) are included in the computation of net periodic benefit cost. See Note J for additional detail of our net periodic benefit cost.

EARNINGS_PER_SHARE

EARNINGS PER SHARE	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
EARNINGS PER SHARE
	I.	EARNINGS PER SHARE
	The following tables set forth the computation of basic and diluted EPS from continuing operations for the periods indicated:
		Three Months Ended March 31, 2015
		Income		Shares	Per Share
					Amount
		(Thousands, except per share amounts)
	Basic EPS from continuing operations
	Income from continuing operations attributable to ONEOK available for common	$	60,944	209,874	$	0.29
	stock
	Diluted EPS from continuing operations
	Effect of dilutive securities	—		593
	Income from continuing operations attributable to ONEOK available for common	$	60,944	210,467	$	0.29
	stock and common stock equivalents
		Three Months Ended March 31, 2014
		Income		Shares	Per Share
					Amount
		(Thousands, except per share amounts)
	Basic EPS from continuing operations
	Income from continuing operations attributable to ONEOK available for common	$	91,741	209,130	$	0.44
	stock
	Diluted EPS from continuing operations
	Effect of dilutive securities	—		1,036
	Income from continuing operations attributable to ONEOK available for common	$	91,741	210,166	$	0.44
	stock and common stock equivalents

EMPLOYEE_BENEFIT_PLANS

EMPLOYEE BENEFIT PLANS	3 Months Ended
	Mar. 31, 2015
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
EMPLOYEE BENEFIT PLANS
	J.	EMPLOYEE BENEFIT PLANS
	The following tables set forth the components of net periodic benefit cost for our pension and postretirement benefit plans for our continuing operations for the periods indicated:
		Pension Benefits
		Three Months Ended
		March 31,
		2015			2014
		(Thousands of dollars)
	Components of net periodic benefit cost
	Service cost	$	1,887		$	1,822
	Interest cost	4,546			4,628
	Expected return on assets	(5,213		)	(4,935		)
	Amortization of unrecognized prior service cost	23			48
	Amortization of net loss	3,987			3,755
	Net periodic benefit cost	$	5,230		$	5,318
		Postretirement Benefits
		Three Months Ended
		March 31,
		2015			2014
		(Thousands of dollars)
	Components of net periodic benefit cost
	Service cost	$	186		$	179
	Interest cost	586			611
	Expected return on assets	(564		)	(555		)
	Amortization of unrecognized prior service cost	(415		)	(415		)
	Amortization of net loss	436			208
	Net periodic benefit cost	$	229		$	28

UNCONSOLIDATED_AFFILIATES

UNCONSOLIDATED AFFILIATES	3 Months Ended
	Mar. 31, 2015
Equity Method Investments and Joint Ventures [Abstract]
UNCONSOLIDATED AFFILIATES
	K.	UNCONSOLIDATED AFFILIATES
	Equity in Net Earnings from Investments - The following table sets forth ONEOK Partners’ equity in net earnings from investments for the periods indicated:
		Three Months Ended
		March 31,
		2015		2014
		(Thousands of dollars)
	Share of investee earnings
	Northern Border Pipeline	$	19,702	$	23,409
	Overland Pass Pipeline Company	6,887		4,731
	Other	4,332		5,519
	Equity in net earnings from investments	$	30,921	$	33,659
	Unconsolidated Affiliates Financial Information - The following table sets forth summarized combined financial information of ONEOK Partners’ unconsolidated affiliates for the periods indicated:
		Three Months Ended
		March 31,
		2015		2014
		(Thousands of dollars)
	Income Statement
	Operating revenues	$	129,581	$	155,279
	Operating expenses	$	57,579	$	71,679
	Net income	$	66,359	$	78,673
	Distributions paid to ONEOK Partners	$	39,429	$	35,070
	ONEOK Partners incurred expenses in transactions with unconsolidated affiliates of $19.9 million and $14.2 million for the three months ended March 31, 2015 and 2014, respectively, primarily related to Overland Pass Pipeline Company and Northern Border Pipeline Company. Accounts payable to ONEOK Partners’ equity method investees at March 31, 2015, and December 31, 2014, were $7.4 million and $20.5 million, respectively.
	Powder River Basin Equity Method Investments - Crude oil and natural gas producers have primarily focused their development efforts on crude oil and NGL-rich supply basins rather than areas with dry natural gas production, such as the coal-bed methane areas in the Powder River Basin.  The reduced coal-bed methane development activities and natural production declines in the dry natural gas formations of the Powder River Basin have resulted in lower natural gas volumes available to be gathered.  While the reserve potential in the dry natural gas formations of the Powder River Basin still exists, future drilling and development in this area will be affected by commodity prices and producers’ alternative prospects.
	We expect the energy commodity price environment to remain depressed for at least the near term. The current commodity price environment has caused crude oil and natural gas producers to reduce drilling for crude oil and natural gas, which we expect will slow volume growth or reduce volumes of natural gas delivered to systems owned by ONEOK Partners’ Powder River Basin equity method investments. A continued decline in volumes gathered in the coal-bed methane area of the Powder River Basin may reduce ONEOK Partners’ ability to recover the carrying value of its equity investments in this area and could result in noncash charges to earnings. The net book value of ONEOK Partners’ equity method investments in this dry natural gas area is $215.3 million, which includes $130.5 million of equity method goodwill.

ONEOK_PARTNERS

ONEOK PARTNERS	3 Months Ended
	Mar. 31, 2015
Related Party Transactions [Abstract]
ONEOK PARTNERS
	L.	ONEOK PARTNERS
	Ownership Interest in ONEOK Partners - Our ownership interest in ONEOK Partners is shown in the table below at March 31, 2015:
	General partner interest	2	%
	Limited partner interest (a)	35.6	%
	Total ownership interest	37.6	%
	(a) - Represents 19.8 million common units and approximately 73.0 million Class B units, which are convertible, at our option, into common units.
	Equity Issuances - ONEOK Partners has an “at-the-market” equity program for the offer and sale from time to time of its common units, up to an aggregate amount of $650 million. The program allows ONEOK Partners to offer and sell its common units at prices it deems appropriate through a sales agent. Sales of common units are made by means of ordinary brokers’ transactions on the NYSE, in block transactions, or as otherwise agreed to between ONEOK Partners and the sales agent. ONEOK Partners is under no obligation to offer and sell common units under the program. At March 31, 2015, ONEOK Partners had approximately $443 million of registered common units available for issuance under its “at-the-market” equity program.
	During the three months ended March 31, 2015, ONEOK Partners sold approximately 1.7 million common units through its “at-the-market” equity program. The net proceeds, including ONEOK Partners GP’s contribution to maintain our 2 percent general partner interest in ONEOK Partners, were approximately $71.6 million, which were used for general partnership purposes.
	As a result of these transactions, our aggregate ownership interest in ONEOK Partners decreased to 37.6 percent at March 31, 2015, from 37.8 percent at December 31, 2014.
	During the three months ended March 31, 2014, ONEOK Partners sold 1.1 million common units through the “at-the-market” program that resulted in net proceeds, including ONEOK Partners GP’s contribution to maintain our 2 percent general partner interest in ONEOK Partners, of approximately $56.5 million and used the proceeds for general partnership purposes.
	We account for the difference between the carrying amount of our investment in ONEOK Partners and the underlying book value arising from issuance of common units by ONEOK Partners as an equity transaction.  If ONEOK Partners issues common units at a price different than our carrying value per unit, we account for the premium or deficiency as an adjustment to paid-in capital. As a result of ONEOK Partners’ issuance of common units, we recognized an increase to paid-in capital of approximately $7.3 million, net of taxes, for the three months ended March 31, 2015.
	Cash Distributions - We receive distributions from ONEOK Partners on the common and Class B units we own and the 2 percent general partner interest, which includes our incentive distribution rights.  Under ONEOK Partners’ partnership agreement, as amended, distributions are made to the partners with respect to each calendar quarter in an amount equal to 100 percent of available cash as defined in the Partnership Agreement, as amended.  Available cash generally will be distributed 98 percent to limited partners and 2 percent to the general partner.  The general partner’s percentage interest in quarterly distributions is increased after certain specified target levels are met during the quarter.  Under the incentive distribution provisions, as set forth in the Partnership Agreement the general partner receives:
	•	15 percent of amounts distributed in excess of $0.3025 per unit;
	•	25 percent of amounts distributed in excess of $0.3575 per unit; and
	•	50 percent of amounts distributed in excess of $0.4675 per unit.
	In April 2015, a cash distribution of $0.79 per unit ($3.16 per unit on an annualized basis) was declared for the first quarter 2015 and will be paid on May 15, 2015, to unitholders of record at the close of business on April 30, 2015.
	The following table shows ONEOK Partners’ distributions paid in the periods indicated:
		Three Months Ended
		March 31,
		2015		2014
		(Thousands, except per unit amounts)
	Distribution per unit	$	0.79	$	0.73
	General partner distributions	$	5,914	$	4,849
	Incentive distributions	89,279		68,255
	Distributions to general partner	95,193		73,104
	Limited partner distributions to ONEOK	73,302		67,737
	Limited partner distributions to noncontrolling interest	127,211		101,655
	Total distributions paid	$	295,706	$	242,496
	The following table shows ONEOK Partners’ distributions declared for the periods indicated and paid within 45 days of the end of the period:
		Three Months Ended
		March 31,
		2015		2014
		(Thousands, except per unit amounts)
	Distribution per unit	$	0.79	$	0.745
	General partner distributions	$	5,955	$	5,011
	Incentive distributions	89,889		71,911
	Distributions to general partner	95,844		76,922
	Limited partner distributions to ONEOK	73,302		69,127
	Limited partner distributions to noncontrolling interest	128,583		104,506
	Total distributions declared	$	297,729	$	250,555
	West Texas LPG Acquisition - In November 2014, ONEOK Partners completed the acquisition of an 80 percent interest in the West Texas LPG Pipeline Limited Partnership and a 100 percent interest in the Mesquite Pipeline for approximately $800 million from affiliates of Chevron Corporation. We accounted for this acquisition as a business combination which, among other things, requires assets acquired and liabilities assumed to be measured at their acquisition-date fair values. Our consolidated balance sheets as of March 31, 2015, and December 31, 2014, reflect the preliminary purchase price allocation based on available information, which is subject to customary adjustments, including working capital. ONEOK Partners is reviewing the valuation to determine the final purchase price allocation. See Note C in the Notes to Consolidated Financial Statements in our Annual Report for additional information on this acquisition.
	Relationship - We consolidate ONEOK Partners in our consolidated financial statements; however, we are restricted from the assets and cash flows of ONEOK Partners except for the distributions we receive. Distributions are declared quarterly by ONEOK Partners GP based on the terms of the Partnership Agreement. See Note N for more information on ONEOK Partners’ results.
	Affiliate Transactions - We provide a variety of services to our affiliates, including cash management and financial services, employee benefits, legal and administrative services by our employees and management, insurance and office space leased in our headquarters building and other field locations.  Where costs are incurred specifically on behalf of an affiliate, the costs are billed directly to the affiliate by us.  In other situations, the costs may be allocated to the affiliates through a variety of methods, depending upon the nature of the expenses and the activities of the affiliates.  Beginning in the second quarter 2014, we allocate substantially all of our general overhead costs to ONEOK Partners as a result of the separation of our natural gas distribution business and the wind down of our energy services business in the first quarter 2014.  For the first quarter 2014, it is not practicable to determine what these general overhead costs would have been on a stand-alone basis.
	The following table shows ONEOK Partners’ transactions with us for the periods indicated:
		Three Months Ended
		March 31,
		2015		2014
		(Thousands of dollars)
	Revenues	$	—	$	53,526
	Expenses
	Cost of sales and fuel	$	—	$	10,835
	Administrative and general expenses	89,528		77,246
	Total expenses	$	89,528	$	88,081
	Prior to the ONE Gas separation, ONEOK Partners provided natural gas sales and transportation and storage services to our former natural gas distribution business. Prior to February 1, 2014, these revenues and related costs were eliminated in consolidation. Beginning February 1, 2014, these revenues represent third-party transactions with ONE Gas and are not eliminated in consolidation, as such sales and services have continued subsequent to the separation and are expected to continue in future periods. Prior to the completion of the energy services wind down, ONEOK Partners provided natural gas and natural gas liquids sales and transportation and storage services to our energy services business. While these transactions were eliminated in consolidation in previous periods, they are now reflected as affiliate transactions and not eliminated in consolidation as these transactions have continued with third parties. See Note B for additional detail on these revenues.

COMMITMENTS_AND_CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES
	M.	COMMITMENTS AND CONTINGENCIES
	Environmental Matters - ONEOK Partners is subject to multiple historical preservation, wildlife preservation and environmental laws and/or regulations that 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 ONEOK Partners 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 ONEOK Partners to fines, penalties and/or interruptions in its operations that could be material to our results of operations. For example, if a leak or spill of hazardous substances or petroleum products occurs from pipelines or facilities that ONEOK Partners owns, operates or otherwise uses, ONEOK Partners could be held jointly and severally liable for all resulting liabilities, including response, investigation and cleanup costs, which could affect materially our results of operations and cash flows.  In addition, emissions 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 at ONEOK Partners’ facilities.  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 ONEOK Partners.
	In June 2013, the Executive Office of the President of the United States (the President) issued the President’s Climate Action Plan, which includes, among other things, plans for further regulatory actions to reduce carbon emissions from various sources. On March 28, 2014, the President released the Climate Action Plan - Strategy to Reduce Methane Emissions (Methane Strategy) that lists a number of actions the federal agencies will undertake to continue to reduce above-ground methane emissions from several industries, including the oil and natural gas sectors. The proposed measures outlined in the Methane Strategy include, without limitation, the following: collaboration with the states to encourage emission reductions; standards to minimize natural gas venting and flaring on public lands; policy recommendations for reducing emissions from energy infrastructure to increase the performance of the nation’s energy transmission, storage and distribution systems; and continued efforts by PHMSA to require pipeline operators to take steps to eliminate leaks and prevent accidental methane releases and evaluate the progress of states in replacing cast-iron pipelines. The impact of any such regulatory actions on ONEOK Partners’ facilities and operations is unknown. ONEOK Partners continues to monitor these developments and the impact they may have on its businesses. Revised or additional statutes or regulations that result in increased compliance costs or additional operating restrictions could have a significant impact on our business, financial position, results of operations and cash flows.
	ONEOK Partners’ expenditures for environmental assessment, mitigation, remediation and compliance to date have not been significant in relation to our financial position, results of operations or cash flows, and its expenditures related to environmental matters have had no material effects on earnings or cash flows during the three months ended March 31, 2015 and 2014.
	In April 2014, the EPA and the United States Army Corps of Engineers proposed a joint rule-making to redefine the definition of “Waters of the United States” under the Clean Water Act. The public comment period on the proposed rule-making has closed, and the publication of the final rule-making has not yet occurred. The impact of any such proposed regulatory actions on our projects, facilities and operations is unknown.
	The EPA’s “Tailoring Rule” regulates greenhouse gas (GHG) emissions at new or modified facilities that meet certain criteria. Affected facilities are required to review best available control technology (BACT), conduct air-quality analysis, impact analysis and public reviews with respect to such emissions.  At current emission threshold levels, this rule has had a minimal impact on ONEOK Partners’ existing facilities.  In addition, on June 23, 2014, the Supreme Court of the United States (Supreme Court), in a case styled, Utility Air Regulatory Group v. EPA, 530 U.S. (2014), held that an industrial facility’s potential to emit GHG emissions alone cannot subject a facility to the permitting requirements for major stationary source provisions of the Clean Air Act. The decision invalidated the EPA’s current Triggering and Tailoring Rule for GHG Prevention of Significant Deterioration (PSD) and Title V requirements as applied to facilities considered major sources only for GHGs. However, the Supreme Court also ruled that to the extent a source pursues a capital project (new construction or expansion of existing facility), which otherwise subjects the source to major source PSD permitting for conventional criteria pollutants, the permitting authorities may impose BACT analysis and emission limits for GHGs from those sources.
	In April 2015, the United States Court of Appeals for the District of Columbia Circuit (D.C. Circuit), on remand from the Supreme Court, issued its further Order following the Supreme Court’s decision in Utility Air Regulatory Group v. EPA. The D.C. Circuit’s Order included the following: (1) it formally vacated EPA regulations implementing the Tailoring Rule to the extent that they require a stationary source to obtain a PSD or Title V permit based solely on the source’s GHG emissions; and (2) ordered EPA to consider whether any further revisions to its regulations are appropriate in light of the Supreme Court’s decision. ONEOK Partners is in the process of evaluating the D.C. Circuit decision and will monitor the further EPA rule-makings to determine what, if any, impact it will have on its existing operations and the opportunities it creates for design decisions for new project applications.
	In July 2011, the EPA issued a proposed rule that would change the air emissions New Source Performance Standards, also known as NSPS, and Maximum Achievable Control Technology requirements applicable to the oil and natural gas industry, including natural gas production, processing, transmission and underground storage sectors. In April 2012, the EPA released the final rule, which includes new NSPS and air toxic standards for a variety of sources within natural gas processing plants, oil and natural gas production facilities and natural gas transmission stations. The rule also regulates emissions from the hydraulic fracturing of wells for the first time. The EPA’s final rule reflects significant changes from the proposal issued in 2011 and allows for more manageable compliance options. The NSPS final rule became effective in October 2012, but the dates for compliance vary and depend in part upon the type of affected facility and the date of construction, reconstruction or modification.
	Proposed amendments to the rule were published in March 2015. The EPA has indicated that further amendments may be issued in 2015. Based on the amendments, our understanding of pending stakeholder responses to the NSPS rule and the proposed rule-making, we do not anticipate a material impact to ONEOK Partners’ anticipated capital, operations and maintenance costs resulting from compliance with the regulation. However, the EPA may issue additional responses, amendments and/or policy guidance on the final rule, which could alter our present expectations. Generally, the NSPS rule will require expenditures for updated emissions controls, monitoring and record-keeping requirements at affected facilities in the crude oil and natural gas industry. We do not expect these expenditures will have a material impact on our results of operations, financial position or cash flows.
	Pipeline Safety - ONEOK Partners is subject to PHMSA regulations, including pipeline asset integrity-management regulations.  The Pipeline Safety Improvement Act of 2002 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 of 2011 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 ONEOK Partners. These issues include, but are not limited to, the following:
	•	an evaluation on whether hazardous natural gas liquids and natural gas pipeline integrity-management requirements should be expanded beyond current high-consequence areas;
	•	a review of all natural gas and hazardous natural gas liquids gathering pipeline exemptions;
	•	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 - Gas Index Pricing Litigation - As previously reported, ONEOK and its subsidiary, ONEOK Energy Services Company, L.P. (OESC), along with several other energy companies, are defending multiple lawsuits arising from alleged market manipulation or false reporting of natural gas prices to natural gas-index publications alleged to have occurred prior to 2003. On April 10, 2013, the United States Court of Appeals for the Ninth Circuit reversed the summary judgments that had been granted in favor of ONEOK, OESC and other unaffiliated defendants in the following cases: Reorganized FLI, Learjet, Arandell, Heartland and NewPage. The Ninth Circuit also reversed the summary judgment that had been granted in favor of OESC on all state law claims asserted in the Sinclair case. ONEOK, OESC and the other unaffiliated defendants appealed to the United States Supreme Court seeking review of the Ninth Circuit decision. On April 21, 2015, the United States Supreme Court affirmed the decision of the Ninth Circuit. The cases will now be remanded back to the trial court (the United States District Court for the District of Nevada) for further proceedings.
	Because of the uncertainty surrounding the Gas Index Pricing Litigation, including an insufficient description of the purported classes and other related matters, we cannot reasonably estimate a range of potential exposures at this time. However, it is reasonably possible that the ultimate resolution of these matters could result in future charges that may be material to our results of operations.
	Other Legal Proceedings - We are a party to various other litigation matters and claims that have arisen in the normal course of our operations. While the results of these various other litigation matters 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 consolidated results of operations, financial position or cash flows.

SEGMENTS

SEGMENTS	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
SEGMENTS
	N.	SEGMENTS
	Segment Descriptions - Our reportable business segments are based upon the segments of ONEOK Partners, which include the following:
	•	the Natural Gas Gathering and Processing segment gathers, treats and processes natural gas;
	•	the Natural Gas Liquids segment gathers, treats, fractionates and transports NGLs and stores, markets and distributes NGL products; and
	•	the Natural Gas Pipelines segment operates regulated interstate and intrastate natural gas transmission pipelines and natural gas storage facilities.
	Other and eliminations consist of the operating and leasing operations of our headquarters building and related parking facility and other amounts needed to reconcile our reportable segments to our consolidated financial statements.
	Accounting Policies - We evaluate performance based principally on each segment’s operating income and equity earnings. The accounting policies of the segments are described in Note A of the Notes to Consolidated Financial Statements in our Annual Report.  Intersegment and affiliate sales are recorded on the same basis as sales to unaffiliated customers and are discussed further in Note L.  Net margin is comprised of total revenues less cost of sales and fuel.  Cost of sales and fuel includes commodity purchases, fuel, storage and transportation costs. Revenues from sales and services provided by ONEOK Partners to our former natural gas distribution business, which were previously disclosed as intersegment revenues and eliminated in consolidation, are now reported as sales to unaffiliated customers for all periods presented.
	Customers - The primary customers of the Natural Gas Gathering and Processing segment are major and independent crude oil and natural gas production companies.  The Natural Gas Liquids segment’s customers are primarily NGL and natural gas gathering and processing companies, major and independent crude oil and natural gas production companies, propane distributors, ethanol producers and petrochemical, refining and NGL marketing companies. The Natural Gas Pipelines segment’s customers include natural gas distribution, electric-generation, natural gas marketing, industrial and major and independent crude oil and natural gas production companies.
	For the three months ended March 31, 2015, ONEOK Partners had one customer, BP p.l.c., from which it received $184.9 million in total revenues from all of the operating segments, or approximately 10 percent of our consolidated revenues. For the three months ended March 31, 2014, ONEOK Partners had no single customer from which it received 10 percent or more of our consolidated revenues.
	Operating Segment Information - The following tables set forth certain selected financial information for our operating segments for the periods indicated:
	Three Months Ended	Natural Gas			Natural Gas			Natural Gas			Other and			Total
	31-Mar-15	Gathering and			Liquids (a)			Pipelines (b)			Eliminations (c)
		Processing
		(Thousands of dollars)
	Sales to unaffiliated customers	$	288,016		$	1,434,813		$	81,930		$	547		$	1,805,306
	Intersegment revenues	167,607			61,279			1,619			(230,505		)	—
	Total revenues	$	455,623		$	1,496,092		$	83,549		$	(229,958	)	$	1,805,306
	Net margin	$	124,692		$	267,227		$	69,123		$	400		$	461,442
	Operating costs	69,209			82,246			27,242			321			179,018
	Depreciation and amortization	35,797			39,294			10,756			108			85,955
	Gain (loss) on sale of assets	1			(8		)	1			—			(6		)
	Operating income	$	19,687		$	145,679		$	31,126		$	(29	)	$	196,463
	Equity in net earnings from investments	$	4,239		$	6,980		$	19,702		$	—		$	30,921
	Investments in unconsolidated affiliates	$	255,419		$	483,257		$	385,528		$	—		$	1,124,204
	Total assets	$	4,887,940		$	8,106,767		$	1,807,978		$	730,388		$	15,533,073
	Noncontrolling interests in consolidated subsidiaries	$	4,156		$	162,958		$	—		$	3,196,016		$	3,363,130
	Capital expenditures	$	255,301		$	73,466		$	9,592		$	5,488		$	343,847
	(a) - The Natural Gas Liquids segment has regulated and nonregulated operations. The Natural Gas Liquids segment’s regulated operations had revenues of $209.8 million, of which $165.3 million was related to sales within the segment, net margin of $124.1 million and operating income of $64.9 million.
	(b) - The Natural Gas Pipelines segment has regulated and nonregulated operations. The Natural Gas Pipelines segment’s regulated operations had revenues of $69.3 million, net margin of $60.9 million and operating income of $27.4 million.
	(c) - Other and Eliminations includes assets of discontinued operations of $36.8 million.
	Three Months Ended	Natural Gas			Natural Gas			Natural Gas			Other and			Total
	31-Mar-14	Gathering and			Liquids (a)			Pipelines (b)			Eliminations (c)
		Processing
		(Thousands of dollars)
	Sales to unaffiliated customers	$	347,016		$	2,670,655		$	91,106		$	993		$	3,109,770
	Sales to affiliated customers	41,214			—			12,312			—			53,526
	Intersegment revenues	373,895			41,157			1,375			(416,427		)	—
	Total revenues	$	762,125		$	2,711,812		$	104,793		$	(415,434	)	$	3,163,296
	Net margin	$	153,554		$	268,978		$	93,489		$	(5,394	)	$	510,627
	Operating costs	64,824			65,102			27,462			(8,277		)	149,111
	Depreciation and amortization	28,842			27,078			10,815			679			67,414
	Gain (loss) on sale of assets	(19		)	(48		)	(83		)	165			15
	Operating income	$	59,869		$	176,750		$	55,129		$	2,369		$	294,117
	Equity in net earnings from investments	$	5,486		$	4,764		$	23,409		$	—		$	33,659
	Investments in unconsolidated affiliates	$	333,054		$	489,120		$	406,880		$	—		$	1,229,054
	Total assets	$	4,048,332		$	6,861,829		$	1,848,594		$	894,379		$	13,653,134
	Noncontrolling interests in consolidated subsidiaries	$	4,597		$	—		$	—		$	2,538,610		$	2,543,207
	Capital expenditures	$	122,891		$	273,063		$	6,627		$	26,944		$	429,525
	(a) - The Natural Gas Liquids segment has regulated and nonregulated operations. The Natural Gas Liquids segment’s regulated operations had revenues of $135.8 million, of which $111.6 million was related to sales within the segment, net margin of $84.7 million and operating income of $45.1 million.
	(b) - The Natural Gas Pipelines segment has regulated and nonregulated operations. The Natural Gas Pipelines segment’s regulated operations had revenues of $81.3 million, net margin of $68.6 million and operating income of $35.1 million.
	(c) - Other and Eliminations includes assets and capital expenditures of discontinued operations of $179.6 million and $23.9 million, respectively.

SUMMARY_OF_SIGNIFICANT_ACCOUNT1

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2015
Accounting Policies [Abstract]
Basis of Accounting	Our accompanying unaudited consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC. These statements have been prepared in accordance with GAAP and reflect all adjustments that, in our opinion, are necessary for a fair presentation of the results for the interim periods presented.  All such adjustments are of a normal recurring nature. The 2014 year-end consolidated balance sheet data was derived from our audited financial statements but does not include all disclosures required by GAAP.  These unaudited consolidated financial statements should be read in conjunction with our audited consolidated financial statements in our Annual Report.
	Our significant accounting policies are consistent with those disclosed in Note A of the Notes to Consolidated Financial Statements in our Annual Report.
	Organization and Nature of Operations - We are the sole general partner and own limited partner units of ONEOK Partners (NYSE: OKS), which together represent an aggregate 37.6 percent interest in ONEOK Partners at March 31, 2015. The results of operations for our former natural gas distribution and energy services businesses have been classified as discontinued operations for all periods presented. See Note B for additional information.
	Unless indicated otherwise, the information in the Notes to the Consolidated Financial Statements relates to our continuing operations.
Accounting Standards Update 2015-03 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	In March 2015, the FASB issued ASU 2015-03, “Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs,” which requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. This guidance is effective for public companies for fiscal years beginning after December 15, 2015, and must be retroactively applied. Early adoption is permitted. We plan to adopt this guidance beginning in the first quarter 2016, and we are evaluating the impact on us.
Accounting Standards Update 2015-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	In February 2015, the FASB issued ASU 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis,” which eliminates the presumption that a general partner should consolidate a limited partnership. It also modifies the evaluation of whether limited partnerships are variable interest entities or voting interest entities and adds requirements that limited partnerships must meet to qualify as voting interest entities. This guidance is effective for public companies for fiscal years beginning after December 15, 2015. We will adopt this guidance in the first quarter 2016, and we are evaluating the impact on us.
Accounting Standards Update 2014-15 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	In August 2014, the FASB issued ASU 2014-15, “Going Concern,” which provides guidance on determining when and how to disclose going-concern uncertainties in the financial statements. The new standard requires management to perform interim and annual assessments of an entity’s ability to continue as a going concern within one year of the date the financial statements are issued. An entity must provide certain disclosures if conditions or events raise substantial doubt about the entity’s ability to continue as a going concern. The standard applies to all entities and is effective for annual periods ending after December 15, 2016, and interim periods thereafter, with early adoption permitted. We will adopt this guidance beginning in the first quarter 2016, and we do not expect it to materially impact us.
Accounting Standards Update 2014-09 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	In May 2014, the FASB issued ASU 2014-09, “Revenue from Contracts with Customers,” which outlines the principles an entity must apply to measure and recognize revenue for entities that enter into contracts to provide goods or services to their customers. The core principle is that an entity should recognize revenue at an amount that reflects the consideration to which the entity expects to be entitled in exchange for transferring goods or services to a customer. The amendment also requires more extensive disaggregated revenue disclosures in interim and annual financial statements. This update is effective for interim and annual periods that begin after December 15, 2016, with either retrospective application for all periods presented or retrospective application with a cumulative effect adjustment. In April 2015, the FASB tentatively deferred the effective date by one year with a final determination to be made after a 30-day comment period. We will adopt this guidance beginning in the first quarter 2017, unless the guidance is deferred, and we are evaluating the impact on us.
Accounting Standards Update 2014-08 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	In April 2014, the FASB issued ASU 2014-08, “Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity,” which alters the definition of a discontinued operation to include only asset disposals that represent a strategic shift with a major effect on an entity's operations and financial results.  The amendment also requires more extensive disclosures about a discontinued operation’s assets, liabilities, income, expenses and cash flows. This guidance will be effective for interim and annual periods for all assets that are disposed of or classified as being held for sale in fiscal years that begin on or after December 15, 2014. We adopted this guidance beginning in the first quarter 2015, and it could impact us in the future if we dispose of any individually significant components.

FAIR_VALUE_MEASUREMENTS_FAIR_V

FAIR VALUE MEASUREMENTS FAIR VALUE MEASUREMENTS (Policies)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Fair Value of Financial Instruments, Policy [Policy Text Block]	Determining Fair Value - We define fair value as the price that would be received from the sale of an asset or the transfer of a liability in an orderly transaction between market participants at the measurement date.  We use 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.
	While many of the contracts in ONEOK Partners’ portfolio are executed in liquid markets where price transparency exists, some contracts are executed in markets for which market prices may exist, but the market may be relatively inactive.  This results in limited price transparency that requires management’s judgment and assumptions to estimate fair values.  For certain transactions, we utilize modeling techniques using NYMEX-settled pricing data and implied forward LIBOR curves. Inputs into our fair value estimates include commodity-exchange prices, over-the-counter quotes, historical correlations of pricing data and LIBOR and other liquid money-market instrument rates.  We also utilize internally developed basis curves that incorporate observable and unobservable market data.  We validate our valuation inputs with third-party information and settlement prices from other sources, where available.
	In addition, as prescribed by the income approach, we compute the fair value of our and ONEOK Partners’ derivative portfolios by discounting the projected future cash flows from our derivative assets and liabilities to present value using interest-rate yields to calculate present-value discount factors derived from LIBOR, Eurodollar futures and interest-rate swaps.  We also take into consideration the potential impact on market prices of liquidating positions in an orderly manner over a reasonable period of time under current market conditions.  We consider current market data in evaluating counterparties’, as well as our own, nonperformance risk, net of collateral, by using specific and sector bond yields and monitoring the credit default swap markets.  Although we use our best estimates to determine the fair value of the derivative contracts we and ONEOK Partners have executed, the ultimate market prices realized could differ from our estimates, and the differences could be material.
	The fair value of our forward-starting interest-rate swaps are determined using financial models that incorporate the implied forward LIBOR yield curve for the same period as the future interest swap settlements.
	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 - fair value measurements are based on unadjusted quoted prices for identical securities in active markets, including NYMEX-settled prices. These balances are comprised predominantly of exchange-traded derivative contracts for natural gas and crude oil.
	•	Level 2 - fair value measurements are based on significant observable pricing inputs, such as NYMEX-settled prices for natural gas and crude oil, and financial models that utilize implied forward LIBOR yield curves for interest-rate swaps.
	•	Level 3 - fair value measurements are based on inputs that may include one or more unobservable inputs, including internally developed basis curves that incorporate observable and unobservable market data, NGL price curves from broker quotes, market volatilities derived from the most recent NYMEX close spot prices and forward LIBOR curves, and adjustments for the credit risk of our counterparties.  We corroborate the data on which our fair value estimates are based using our market knowledge of recent transactions, analysis of historical correlations and validation with independent broker quotes.  These balances categorized as Level 3 are comprised of derivatives for natural gas and NGLs.  We do not believe that our Level 3 fair value estimates have a material impact on our results of operations, as the majority of our derivatives are accounted for as hedges for which ineffectiveness is not material.
	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.

RISK_MANAGEMENT_AND_HEDGING_AC1

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES (Policies)	3 Months Ended
	Mar. 31, 2015
RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES [Abstract]
Accounting treatment for derivative instruments	Accounting Treatment - We and ONEOK Partners record all derivative instruments at fair value, with the exception of normal purchases and normal sales transactions that are expected to result in physical delivery.  Commodity price and interest-rate volatility may have a significant impact on the fair value of derivative instruments as of a given date. 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.
	The table below summarizes the various ways in which we account for our derivative instruments and the impact on our consolidated financial statements:
			Recognition and Measurement
	Accounting Treatment		Balance Sheet		Income Statement
	Normal purchases and normal	-	Fair value not recorded	-	Change in fair value not recognized in earnings
	sales
	Mark-to-market	-	Recorded at fair value	-	Change in fair value recognized in earnings
	Cash flow hedge	-	Recorded at fair value	-	Ineffective portion of the gain or loss on the
					derivative instrument is recognized in earnings
		-	Effective portion of the gain or loss on the	-	Effective portion of the gain or loss on the
			derivative instrument is reported initially		derivative instrument is reclassified out of
			as a component of accumulated other		accumulated other comprehensive income (loss)
			comprehensive income (loss)		into earnings when the forecasted transaction
					affects earnings
	Fair value hedge	-	Recorded at fair value	-	The gain or loss on the derivative instrument is
					recognized in earnings
		-	Change in fair value of the hedged item is	-	Change in fair value of the hedged item is
			recorded as an adjustment to book value		recognized in earnings
	To reduce its exposure to fluctuations in natural gas, NGLs and condensate prices, ONEOK Partners periodically enters into futures, forward sales, options or swap transactions in order to hedge anticipated purchases and sales of natural gas, NGLs and condensate.  Interest-rate swaps are used from time to time to manage interest-rate risk.  Under certain conditions, we designate these derivative instruments as a hedge of exposure to changes in fair values or cash flows.  We formally document all relationships between hedging instruments and hedged items, as well as risk-management objectives and strategies for undertaking various hedge transactions and methods for assessing and testing correlation and hedge ineffectiveness.  We specifically identify the forecasted transaction that has been designated as the hedged item in a cash flow hedge relationship. We assess the effectiveness of hedging relationships quarterly by performing an effectiveness analysis on our fair value and cash flow hedging relationships to determine whether the hedge relationships are highly effective on a retrospective and prospective basis.  ONEOK Partners also documents its normal purchases and normal sales transactions that are expected to result in physical delivery and that ONEOK Partners elects to exempt from derivative accounting treatment.
	The realized revenues and purchase costs of our and ONEOK Partners’ derivative instruments not considered held for trading purposes and derivatives that qualify as normal purchases or normal sales that are expected to result in physical delivery are reported on a gross basis. Cash flows from futures, forwards and swaps that are accounted for as hedges are included in the same category as the cash flows from the related hedged items in our Consolidated Statements of Cash Flows.
	For the three months ended March 31, 2014, income from discontinued operations in our Consolidated Statements of Income includes revenues from financial trading margins, as well as certain physical natural gas transactions with our trading counterparties. Revenues and cost of sales and fuel from such physical transactions are reported on a net basis.

ONEOK_PARTNERS_Policies

ONEOK PARTNERS (Policies)	3 Months Ended
	Mar. 31, 2015
Related Party Transactions [Abstract]
Consolidation, Subsidiaries or Other Investments, Consolidated Entities, Policy [Policy Text Block]	We account for the difference between the carrying amount of our investment in ONEOK Partners and the underlying book value arising from issuance of common units by ONEOK Partners as an equity transaction.  If ONEOK Partners issues common units at a price different than our carrying value per unit, we account for the premium or deficiency as an adjustment to paid-in capital. As a result of ONEOK Partners’ issuance of common units, we recognized an increase to paid-in capital of approximately $7.3 million, net of taxes, for the three months ended March 31, 2015.
Cash Distributions	Cash Distributions - We receive distributions from ONEOK Partners on the common and Class B units we own and the 2 percent general partner interest, which includes our incentive distribution rights.  Under ONEOK Partners’ partnership agreement, as amended, distributions are made to the partners with respect to each calendar quarter in an amount equal to 100 percent of available cash as defined in the Partnership Agreement, as amended.  Available cash generally will be distributed 98 percent to limited partners and 2 percent to the general partner.  The general partner’s percentage interest in quarterly distributions is increased after certain specified target levels are met during the quarter.  Under the incentive distribution provisions, as set forth in the Partnership Agreement the general partner receives:
	•	15 percent of amounts distributed in excess of $0.3025 per unit;
	•	25 percent of amounts distributed in excess of $0.3575 per unit; and
	•	50 percent of amounts distributed in excess of $0.4675 per unit.
Business Combinations Policy [Policy Text Block]	We accounted for this acquisition as a business combination which, among other things, requires assets acquired and liabilities assumed to be measured at their acquisition-date fair values.
Allocation of Costs Incurred by Related Party, Policy [Policy Text Block]	We provide a variety of services to our affiliates, including cash management and financial services, employee benefits, legal and administrative services by our employees and management, insurance and office space leased in our headquarters building and other field locations.  Where costs are incurred specifically on behalf of an affiliate, the costs are billed directly to the affiliate by us.  In other situations, the costs may be allocated to the affiliates through a variety of methods, depending upon the nature of the expenses and the activities of the affiliates.  Beginning in the second quarter 2014, we allocate substantially all of our general overhead costs to ONEOK Partners as a result of the separation of our natural gas distribution business and the wind down of our energy services business in the first quarter 2014.  For the first quarter 2014, it is not practicable to determine what these general overhead costs would have been on a stand-alone basis.

SEGMENTS_SEGMENTS_Policies

SEGMENTS SEGMENTS (Policies)	3 Months Ended
	Mar. 31, 2015
Segment Accounting Policies [Abstract]
Segments Accounting Policies [Text Block]	Accounting Policies - We evaluate performance based principally on each segment’s operating income and equity earnings. The accounting policies of the segments are described in Note A of the Notes to Consolidated Financial Statements in our Annual Report.  Intersegment and affiliate sales are recorded on the same basis as sales to unaffiliated customers and are discussed further in Note L.  Net margin is comprised of total revenues less cost of sales and fuel.  Cost of sales and fuel includes commodity purchases, fuel, storage and transportation costs. Revenues from sales and services provided by ONEOK Partners to our former natural gas distribution business, which were previously disclosed as intersegment revenues and eliminated in consolidation, are now reported as sales to unaffiliated customers for all periods presented.

DISCONTINUED_OPERATIONS_Tables

DISCONTINUED OPERATIONS (Tables)	3 Months Ended
	Mar. 31, 2015
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Restructuring and Related Costs [Table Text Block]	The following table summarizes the change in our liability related to released capacity contracts for the periods indicated:
		Three Months Ended
		March 31,
		2015				2014
		(Millions of dollars)
	Beginning balance	$	73.8			$	122
	Noncash charges	—				1.7
	Settlements	(12.8		)		(12.8		)
	Accretion	0.3				0.6
	Ending balance	$	61.3			$	111.5
Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block]	Results of Operations of Discontinued Operations - The results of operations for our former natural gas distribution business and energy services business have been reported as discontinued operations for all periods presented. Income (loss) from discontinued operations, net of tax, in the Consolidated Statements of Income for the three months ended March 31, 2015, consists of accretion expense, net of tax benefit, on the released contracts for our former energy services business. The table below provides selected financial information reported in discontinued operations in the Consolidated Statements of Income for the three months ended March, 31, 2014:
		Three Months Ended
		31-Mar-14
		Natural Gas				Energy			Total
		Distribution				Services
		(Thousands of dollars)
	Revenues	$	287,249			$	353,404		$	640,653
	Cost of sales and fuel	190,893				364,648			555,541
	Net margin	96,356				(11,244		)	85,112
	Operating costs	59,431			(a)	3,127			62,558
	Depreciation and amortization	11,035				319			11,354
	Operating income (loss)	25,890				(14,690		)	11,200
	Other income (expense), net	(888		)		(7		)	(895		)
	Interest expense, net	(4,592		)		(413		)	(5,005		)
	Income taxes	(10,670		)		7,144			(3,526		)
	Income (loss) from discontinued operations, net	$	9,740			$	(7,966	)	$	1,774
	(a) - Includes approximately $21.7 million for the three months ended March 31, 2014, of costs related to ONE Gas separation.

FAIR_VALUE_MEASUREMENTS_Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2015
Fair Value Disclosures [Abstract]
Recurring Fair Value Measurments	Recurring Fair Value Measurements - The following tables set forth our recurring fair value measurements for our continuing operations for the periods indicated:
		March 31, 2015
		Level 1			Level 2			Level 3			Total - Gross			Netting (a)			Total - Net (b)
		(Thousands of dollars)
	Derivative assets
	Commodity contracts
	Financial contracts	$	38,445		$	—		$	3,183		$	41,628		$	(18,224	)	$	23,404
	Physical contracts	—			—			7,395			7,395			—			7,395
	Total derivative assets	$	38,445		$	—		$	10,578		$	49,023		$	(18,224	)	$	30,799
	Derivative liabilities
	Commodity contracts
	Financial contracts	$	(231	)	$	—		$	(3,538	)	$	(3,769	)	$	3,769		$	—
	Interest-rate contracts	—			(9,947		)	—			(9,947		)	—			(9,947		)
	Total derivative liabilities	$	(231	)	$	(9,947	)	$	(3,538	)	$	(13,716	)	$	3,769		$	(9,947	)
	(a) - Derivative assets and liabilities are presented in our Consolidated Balance Sheets on a net basis.  We net derivative assets and liabilities when a legally enforceable master-netting arrangement exists between the counterparty to a derivative contract and ONEOK Partners.  At March 31, 2015, ONEOK Partners had $14.5 million of cash held from various counterparties and posted no cash collateral.
	(b) - Included in other current assets or deferred credits and other liabilities in our Consolidated Balance Sheets.
		December 31, 2014
		Level 1			Level 2			Level 3			Total - Gross			Netting (a)			Total - Net (b)
		(Thousands of dollars)
	Assets
	Derivatives
	Commodity contracts
	Financial contracts	$	42,880		$	—		$	354		$	43,234		$	(25,979	)	$	17,255
	Physical contracts	—			—			9,922			9,922			—			9,922
	Interest-rate contracts	—			2,288			—			2,288			—			2,288
	Total derivative assets	42,880			2,288			10,276			55,444			(25,979		)	29,465
	Available-for-sale investment securities	1,773			—			—			1,773			—			1,773
	Total assets	$	44,653		$	2,288		$	10,276		$	57,217		$	(25,979	)	$	31,238
	Liabilities
	Derivatives
	Commodity contracts
	Financial contracts	$	(169	)	$	—		$	(968	)	$	(1,137	)	$	1,137		$	—
	Physical contracts	—			—			(23		)	(23		)	—			(23		)
	Interest-rate contracts	—			(44,843		)	—			(44,843		)	—			(44,843		)
	Total derivative liabilities	$	(169	)	$	(44,843	)	$	(991	)	$	(46,003	)	$	1,137		$	(44,866	)
	(a) - Derivative assets and liabilities are presented in our Consolidated Balance Sheets on a net basis. We net derivative assets and liabilities when a legally enforceable master-netting arrangement exists between the counterparty to a derivative contract and ONEOK Partners. At December 31, 2014, ONEOK Partners had $24.8 million of cash held from various counterparties and posted no cash collateral.
	(b) - Included in other current assets, other assets or other current liabilities in our Consolidated Balance Sheets.
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation	The following table sets forth a reconciliation of our Level 3 fair value measurements for our continuing operations for the periods indicated:
		Three Months Ended
		March 31,
	Derivative Assets (Liabilities)	2015			2014
		(Thousands of dollars)
	Net assets (liabilities) at beginning of period	$	9,285		$	(782	)
	Total realized/unrealized gains (losses):
	Included in earnings (a)	269			(928		)
	Included in other comprehensive income (loss)	(2,514		)	(52		)
	Purchases, issuances and settlements	—			3,734
	Net assets (liabilities) at end of period	$	7,040		$	1,972
	(a) - Included in commodity sales revenues in our Consolidated Statements of Income.

RISK_MANAGEMENT_AND_HEDGING_AC2

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES (Tables)	3 Months Ended
	Mar. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair value of derivatives	Fair Values of Derivative Instruments - See Note C for a discussion of the inputs associated with our fair value measurements. The following table sets forth the fair values of derivative instruments for our continuing operations for the periods indicated:
		March 31, 2015								December 31, 2014
		Assets (a)				(Liabilities) (a)				Assets (a)			(Liabilities) (a)
		(Thousands of dollars)
	Derivatives designated as hedging instruments
	Commodity contracts
	Financial contracts	$	41,053			$	(3,565	)		$	43,234		$	(1,137	)
	Physical contracts	7,395				—				9,922			—
	Interest-rate contracts	—				(9,947		)		2,288			(44,843		)
	Total derivatives designated as hedging instruments	48,448				(13,512		)		55,444			(45,980		)
	Derivatives not designated as hedging instruments
	Commodity contracts
	Financial contracts	575				(204		)		—			—
	Physical contracts	—				—				—			(23		)
	Total derivatives not designated as hedging instruments	575				(204		)		—			(23		)
	Total derivatives	$	49,023			$	(13,716	)		$	55,444		$	(46,003	)
	(a) - Included on a net basis in other current assets or deferred credits and other liabilities in our Consolidated Balance Sheets.
Notional amounts of derivative instruments	Notional Quantities for Derivative Instruments - The following table sets forth the notional quantities for derivative instruments for our continuing operations for the periods indicated:
			March 31, 2015								December 31, 2014
		Contract	Purchased/				Sold/				Purchased/			Sold/
		Type	Payor				Receiver				Payor			Receiver
	Derivatives designated as hedging instruments:
	Cash flow hedges
	Fixed price
	- Natural gas (Bcf)	Futures and swaps	—				(45.5		)		—			(41.2		)
	- Crude oil and NGLs (MMBbl)	Futures, forwards	—				(4.1		)		—			(0.5		)
		and swaps
	Basis
	- Natural gas (Bcf)	Futures and swaps	—				(45.5		)		—			(41.2		)
	Interest-rate contracts (Millions of dollars)	Forward-starting	$	400			$	—			$	900		$	—
		swaps
	Derivatives not designated as hedging instruments:
	Fixed price
	- Crude oil and NGLs (MMBbl)	Futures, forwards	0.6				(0.6		)		—			—
		and swaps
Schedule of cash flow hedging instruments effect on comprehensive income (loss)	The following table sets forth the unrealized effect of cash flow hedges recognized in other comprehensive income (loss) for the periods indicated:
	Derivatives in Cash Flow	Three Months Ended
	Hedging Relationships	March 31,
		2015				2014
		(Thousands of dollars)
	Continuing Operations
	Commodity contracts	$	10,019			$	(35,762	)
	Interest-rate contracts	(22,576		)		(20,693		)
	Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion) for continuing operations	(12,557		)		(56,455		)
	Discontinued Operations
	Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion) for discontinued operations - commodity contracts	—				(3,697		)
	Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion)	$	(12,557	)		$	(60,152	)
Schedule of cash flow hedging instruments effect on income	The following table sets forth the effect of cash flow hedges in our Consolidated Statements of Income for the periods indicated:
	Derivatives in Cash Flow	Location of Gain (Loss) Reclassified from	Three Months Ended
	Hedging Relationships	Accumulated Other Comprehensive Income	March 31,
		(Loss) into Net Income (Effective Portion)	2015				2014
			(Thousands of dollars)
	Continuing Operations
	Commodity contracts	Commodity sales revenues	$	14,172			$	(26,419	)
	Interest-rate contracts	Interest expense	(3,717		)		(11,321		)
	Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income on derivatives (effective portion)		10,455				(37,740		)
	Discontinued Operations
	Commodity contracts	Income (loss) from discontinued operations -	—				(12,803		)
		Commodity sales revenues
	Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income from discontinued operations on derivatives (effective portion)		—				(12,803		)
	Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income on derivatives (effective portion)		$	10,455			$	(50,543	)

EQUITY_Tables

EQUITY (Tables)	3 Months Ended
	Mar. 31, 2015
Equity [Abstract]
Changes in equity, including other comprehensive income, net of tax	The following table sets forth the changes in equity attributable to us and our noncontrolling interests, including other comprehensive income, net of tax, for the periods indicated:
		Three Months Ended									Three Months Ended
		31-Mar-15									31-Mar-14
		ONEOK			Noncontrolling			Total			ONEOK			Noncontrolling			Total
		Shareholders’			Interests in			Equity			Shareholders’			Interests in			Equity
		Equity			Consolidated						Equity			Consolidated
					Subsidiaries									Subsidiaries
		(Thousands of dollars)
	Beginning balance	$	592,115		$	3,413,768		$	4,005,883		$	2,337,851		$	2,507,329		$	4,845,180
	Net income	60,800			34,893			95,693			93,515			112,996			206,511
	Other comprehensive income	(3,539		)	(15,086		)	(18,625		)	8,685			(17,309		)	(8,624		)
	(loss)
	Common stock issued	3,800			—			3,800			7,579			—			7,579
	Common stock dividends	(126,053		)	—			(126,053		)	(83,275		)	—			(83,275		)
	Issuance of common units of	7,261			59,012			66,273			10,996			41,846			52,842
	ONEOK Partners
	Distribution of ONE Gas to shareholders	—			—			—			(1,747,424		)	—			(1,747,424		)
	Distributions to noncontrolling	—			(129,457		)	(129,457		)	—			(101,655		)	(101,655		)
	interests
	Other	(4,226		)	—			(4,226		)	(43,427		)	—			(43,427		)
	Ending balance	$	530,158		$	3,363,130		$	3,893,288		$	584,500		$	2,543,207		$	3,127,707

ACCUMULATED_OTHER_COMPREHENSIV1

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	3 Months Ended
	Mar. 31, 2015
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Accumulated other comprehensive income (loss)	The following table sets forth the balance in accumulated other comprehensive income (loss) for the period indicated:
		Unrealized Gains				Unrealized				Pension and			Accumulated
		(Losses) on Energy				Holding Gains				Postretirement			Other
		Marketing and				(Losses)				Benefit Plan			Comprehensive
		Risk-Management				on Investment				Obligations (a) (b)			Income (Loss) (a)
		Assets/Liabilities (a)				Securities (a)
		(Thousands of dollars)
	1-Jan-15	$	(37,349	)		$	955			$	(99,959	)	$	(136,353	)
	Other comprehensive income (loss) before	(2,864		)		(955		)		19			(3,800		)
	reclassifications
	Amounts reclassified from accumulated other	(2,158		)		—				2,419			261
	comprehensive income (loss)
	Net current period other comprehensive income	(5,022		)		(955		)		2,438			(3,539		)
	(loss) attributable to ONEOK
	March 31, 2015	$	(42,371	)		$	—			$	(97,521	)	$	(139,892	)
	(a) All amounts are presented net of tax.
	(b) Includes amounts related to supplemental executive retirement plan.
Statement [Line Items]
Disclosure of Reclassification Amount [Text Block]	The following table sets forth the effect of reclassifications from accumulated other comprehensive income (loss) in our Consolidated Statements of Income for the periods indicated:
	Details about Accumulated Other		Three Months Ended								Affected Line Item in the
	Comprehensive Income (Loss) Components		March 31,								Consolidated Statements of Income
			2015				2014
			(Thousands of dollars)
	Unrealized (gains) losses on energy marketing and risk-management assets/liabilities
	Commodity contracts		$	(14,172	)		$	26,419			Commodity sales revenues
	Interest-rate contracts		3,717				11,321				Interest expense
			(10,455		)		37,740				Income before income taxes
			1,225				(7,896		)		Income tax expense
			(9,230		)		29,844				Income from continuing operations
			—				7,683				Income (loss) from discontinued operations
			(9,230		)		37,527				Net income
	Noncontrolling interest		(7,072		)		17,109				Less: Net income attributable to noncontrolling interest
			$	(2,158	)		$	20,418			Net income (loss) attributable to ONEOK
	Pension and postretirement benefit plan obligations (a)
	Amortization of net loss		$	4,423			$	3,963
	Amortization of unrecognized prior service cost		(392		)		(367		)
			4,031				3,596				Income before income taxes
			(1,612		)		(1,438		)		Income tax expense
			2,419				2,158				Income from continuing operations
			—				1,648				Income from discontinued operations
			$	2,419			$	3,806			Net income attributable to ONEOK
	Total reclassifications for the period attributable to ONEOK		$	261			$	24,224			Net income attributable to ONEOK
	(a) These components of accumulated other comprehensive income (loss) are included in the computation of net periodic benefit cost. See Note J for additional detail of our net periodic benefit cost.

EARNINGS_PER_SHARE_Tables

EARNINGS PER SHARE (Tables)	3 Months Ended
	Mar. 31, 2015
Earnings Per Share [Abstract]
Earnings Per Share	The following tables set forth the computation of basic and diluted EPS from continuing operations for the periods indicated:
		Three Months Ended March 31, 2015
		Income		Shares	Per Share
					Amount
		(Thousands, except per share amounts)
	Basic EPS from continuing operations
	Income from continuing operations attributable to ONEOK available for common	$	60,944	209,874	$	0.29
	stock
	Diluted EPS from continuing operations
	Effect of dilutive securities	—		593
	Income from continuing operations attributable to ONEOK available for common	$	60,944	210,467	$	0.29
	stock and common stock equivalents
		Three Months Ended March 31, 2014
		Income		Shares	Per Share
					Amount
		(Thousands, except per share amounts)
	Basic EPS from continuing operations
	Income from continuing operations attributable to ONEOK available for common	$	91,741	209,130	$	0.44
	stock
	Diluted EPS from continuing operations
	Effect of dilutive securities	—		1,036
	Income from continuing operations attributable to ONEOK available for common	$	91,741	210,166	$	0.44
	stock and common stock equivalents

EMPLOYEE_BENEFIT_PLANS_Tables

EMPLOYEE BENEFIT PLANS (Tables)	3 Months Ended
	Mar. 31, 2015
Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]
The components of net periodic benefit cost	The following tables set forth the components of net periodic benefit cost for our pension and postretirement benefit plans for our continuing operations for the periods indicated:
		Pension Benefits
		Three Months Ended
		March 31,
		2015			2014
		(Thousands of dollars)
	Components of net periodic benefit cost
	Service cost	$	1,887		$	1,822
	Interest cost	4,546			4,628
	Expected return on assets	(5,213		)	(4,935		)
	Amortization of unrecognized prior service cost	23			48
	Amortization of net loss	3,987			3,755
	Net periodic benefit cost	$	5,230		$	5,318
		Postretirement Benefits
		Three Months Ended
		March 31,
		2015			2014
		(Thousands of dollars)
	Components of net periodic benefit cost
	Service cost	$	186		$	179
	Interest cost	586			611
	Expected return on assets	(564		)	(555		)
	Amortization of unrecognized prior service cost	(415		)	(415		)
	Amortization of net loss	436			208
	Net periodic benefit cost	$	229		$	28

UNCONSOLIDATED_AFFILIATES_Tabl

UNCONSOLIDATED AFFILIATES (Tables)	3 Months Ended
	Mar. 31, 2015
Equity Method Investments and Joint Ventures [Abstract]
Equity in Net Earnings from Investments	Equity in Net Earnings from Investments - The following table sets forth ONEOK Partners’ equity in net earnings from investments for the periods indicated:
		Three Months Ended
		March 31,
		2015		2014
		(Thousands of dollars)
	Share of investee earnings
	Northern Border Pipeline	$	19,702	$	23,409
	Overland Pass Pipeline Company	6,887		4,731
	Other	4,332		5,519
	Equity in net earnings from investments	$	30,921	$	33,659
Unconsolidated Affiliates Financial Information [Table Text Block]	Unconsolidated Affiliates Financial Information - The following table sets forth summarized combined financial information of ONEOK Partners’ unconsolidated affiliates for the periods indicated:
		Three Months Ended
		March 31,
		2015		2014
		(Thousands of dollars)
	Income Statement
	Operating revenues	$	129,581	$	155,279
	Operating expenses	$	57,579	$	71,679
	Net income	$	66,359	$	78,673
	Distributions paid to ONEOK Partners	$	39,429	$	35,070

ONEOK_PARTNERS_Tables

ONEOK PARTNERS (Tables)	3 Months Ended
	Mar. 31, 2015
Related Party Transactions [Abstract]
ONEOK Partners' Distributions Paid	The following table shows ONEOK Partners’ distributions paid in the periods indicated:
		Three Months Ended
		March 31,
		2015		2014
		(Thousands, except per unit amounts)
	Distribution per unit	$	0.79	$	0.73
	General partner distributions	$	5,914	$	4,849
	Incentive distributions	89,279		68,255
	Distributions to general partner	95,193		73,104
	Limited partner distributions to ONEOK	73,302		67,737
	Limited partner distributions to noncontrolling interest	127,211		101,655
	Total distributions paid	$	295,706	$	242,496
ONEOK Partners' Distributions Declared	The following table shows ONEOK Partners’ distributions declared for the periods indicated and paid within 45 days of the end of the period:
		Three Months Ended
		March 31,
		2015		2014
		(Thousands, except per unit amounts)
	Distribution per unit	$	0.79	$	0.745
	General partner distributions	$	5,955	$	5,011
	Incentive distributions	89,889		71,911
	Distributions to general partner	95,844		76,922
	Limited partner distributions to ONEOK	73,302		69,127
	Limited partner distributions to noncontrolling interest	128,583		104,506
	Total distributions declared	$	297,729	$	250,555
ONEOK Partners' transactions	Ownership Interest in ONEOK Partners - Our ownership interest in ONEOK Partners is shown in the table below at March 31, 2015:
	General partner interest	2	%
	Limited partner interest (a)	35.6	%
	Total ownership interest	37.6	%
	(a) - Represents 19.8 million common units and approximately 73.0 million Class B units, which are convertible, at our option, into common units.
	The following table shows ONEOK Partners’ transactions with us for the periods indicated:
		Three Months Ended
		March 31,
		2015		2014
		(Thousands of dollars)
	Revenues	$	—	$	53,526
	Expenses
	Cost of sales and fuel	$	—	$	10,835
	Administrative and general expenses	89,528		77,246
	Total expenses	$	89,528	$	88,081

SEGMENTS_Tables

SEGMENTS (Tables)	3 Months Ended
	Mar. 31, 2015
Segment Reporting [Abstract]
Segments	The following tables set forth certain selected financial information for our operating segments for the periods indicated:
	Three Months Ended	Natural Gas			Natural Gas			Natural Gas			Other and			Total
	31-Mar-15	Gathering and			Liquids (a)			Pipelines (b)			Eliminations (c)
		Processing
		(Thousands of dollars)
	Sales to unaffiliated customers	$	288,016		$	1,434,813		$	81,930		$	547		$	1,805,306
	Intersegment revenues	167,607			61,279			1,619			(230,505		)	—
	Total revenues	$	455,623		$	1,496,092		$	83,549		$	(229,958	)	$	1,805,306
	Net margin	$	124,692		$	267,227		$	69,123		$	400		$	461,442
	Operating costs	69,209			82,246			27,242			321			179,018
	Depreciation and amortization	35,797			39,294			10,756			108			85,955
	Gain (loss) on sale of assets	1			(8		)	1			—			(6		)
	Operating income	$	19,687		$	145,679		$	31,126		$	(29	)	$	196,463
	Equity in net earnings from investments	$	4,239		$	6,980		$	19,702		$	—		$	30,921
	Investments in unconsolidated affiliates	$	255,419		$	483,257		$	385,528		$	—		$	1,124,204
	Total assets	$	4,887,940		$	8,106,767		$	1,807,978		$	730,388		$	15,533,073
	Noncontrolling interests in consolidated subsidiaries	$	4,156		$	162,958		$	—		$	3,196,016		$	3,363,130
	Capital expenditures	$	255,301		$	73,466		$	9,592		$	5,488		$	343,847
	(a) - The Natural Gas Liquids segment has regulated and nonregulated operations. The Natural Gas Liquids segment’s regulated operations had revenues of $209.8 million, of which $165.3 million was related to sales within the segment, net margin of $124.1 million and operating income of $64.9 million.
	(b) - The Natural Gas Pipelines segment has regulated and nonregulated operations. The Natural Gas Pipelines segment’s regulated operations had revenues of $69.3 million, net margin of $60.9 million and operating income of $27.4 million.
	(c) - Other and Eliminations includes assets of discontinued operations of $36.8 million.
	Three Months Ended	Natural Gas			Natural Gas			Natural Gas			Other and			Total
	31-Mar-14	Gathering and			Liquids (a)			Pipelines (b)			Eliminations (c)
		Processing
		(Thousands of dollars)
	Sales to unaffiliated customers	$	347,016		$	2,670,655		$	91,106		$	993		$	3,109,770
	Sales to affiliated customers	41,214			—			12,312			—			53,526
	Intersegment revenues	373,895			41,157			1,375			(416,427		)	—
	Total revenues	$	762,125		$	2,711,812		$	104,793		$	(415,434	)	$	3,163,296
	Net margin	$	153,554		$	268,978		$	93,489		$	(5,394	)	$	510,627
	Operating costs	64,824			65,102			27,462			(8,277		)	149,111
	Depreciation and amortization	28,842			27,078			10,815			679			67,414
	Gain (loss) on sale of assets	(19		)	(48		)	(83		)	165			15
	Operating income	$	59,869		$	176,750		$	55,129		$	2,369		$	294,117
	Equity in net earnings from investments	$	5,486		$	4,764		$	23,409		$	—		$	33,659
	Investments in unconsolidated affiliates	$	333,054		$	489,120		$	406,880		$	—		$	1,229,054
	Total assets	$	4,048,332		$	6,861,829		$	1,848,594		$	894,379		$	13,653,134
	Noncontrolling interests in consolidated subsidiaries	$	4,597		$	—		$	—		$	2,538,610		$	2,543,207
	Capital expenditures	$	122,891		$	273,063		$	6,627		$	26,944		$	429,525
	(a) - The Natural Gas Liquids segment has regulated and nonregulated operations. The Natural Gas Liquids segment’s regulated operations had revenues of $135.8 million, of which $111.6 million was related to sales within the segment, net margin of $84.7 million and operating income of $45.1 million.
	(b) - The Natural Gas Pipelines segment has regulated and nonregulated operations. The Natural Gas Pipelines segment’s regulated operations had revenues of $81.3 million, net margin of $68.6 million and operating income of $35.1 million.
	(c) - Other and Eliminations includes assets and capital expenditures of discontinued operations of $179.6 million and $23.9 million, respectively.

SUMMARY_OF_SIGNIFICANT_ACCOUNT2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details)	3 Months Ended	12 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
Entity [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	37.60%	37.80%

DISCONTINUED_OPERATIONS_Detail

DISCONTINUED OPERATIONS (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014	Dec. 31, 2013
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Accumulated charges attributable to exit activities	$61,300,000	$111,500,000	$73,800,000	$122,000,000
Noncash charges	0	1,739,000
Settlements	-12,800,000	-12,800,000
Accretion	300,000	600,000
Effect on future cash flows, amount	37,000,000
Disposal group, including discontinued operation, revenue		640,653,000
Disposal group, including discontinued operation, costs of sales and fuel		555,541,000
Disposal group, including discontinued operation, net margin		85,112,000
Disposal group, including discontinued operation, operating costs		62,558,000
Disposal group, including discontinued operation, depreciation and amortization		11,354,000
Disposal group, including discontinued operation, operating income (loss)		11,200,000
Disposal group, including discontinued operation, other income (expense), net		-895,000
Disposal group, including discontinued operation, interest expense, net		-5,005,000
Discontinued operation, income taxes		-3,526,000
Income (loss) from discontinued operations, net of tax, including portion attributable to noncontrolling interest	-144,000	1,774,000
Costs related to separation		21,700,000
Natural Gas Distribution [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group, including discontinued operation, revenue		287,249,000
Disposal group, including discontinued operation, costs of sales and fuel		190,893,000
Disposal group, including discontinued operation, net margin		96,356,000
Disposal group, including discontinued operation, operating costs		59,431,000
Disposal group, including discontinued operation, depreciation and amortization		11,035,000
Disposal group, including discontinued operation, operating income (loss)		25,890,000
Disposal group, including discontinued operation, other income (expense), net		-888,000
Disposal group, including discontinued operation, interest expense, net		-4,592,000
Discontinued operation, income taxes		-10,670,000
Income (loss) from discontinued operations, net of tax, including portion attributable to noncontrolling interest		9,740,000
Energy Services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal group, including discontinued operation, revenue		353,404,000
Disposal group, including discontinued operation, costs of sales and fuel		364,648,000
Disposal group, including discontinued operation, net margin		-11,244,000
Disposal group, including discontinued operation, operating costs		3,127,000
Disposal group, including discontinued operation, depreciation and amortization		319,000
Disposal group, including discontinued operation, operating income (loss)		-14,690,000
Disposal group, including discontinued operation, other income (expense), net		-7,000
Disposal group, including discontinued operation, interest expense, net		-413,000
Discontinued operation, income taxes		7,144,000
Income (loss) from discontinued operations, net of tax, including portion attributable to noncontrolling interest		-7,966,000
2015 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Effect on future cash flows, amount	15,000,000
2016 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Effect on future cash flows, amount	11,000,000
2017 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Effect on future cash flows, amount	6,000,000
2018 - 2023 [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Effect on future cash flows, amount	5,000,000
ONEOK Partners [Member] | Natural Gas Distribution [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Related Party Transaction, Other Revenues from Transactions with Related Party		7,500,000
ONEOK Partners [Member] | Energy Services [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Related Party Transaction, Other Revenues from Transactions with Related Party		$46,000,000

FAIR_VALUE_MEASUREMENTS_Part_1

FAIR VALUE MEASUREMENTS - Part 1 (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash collateral held	$14,500,000	$24,800,000
Cash collateral posted	0	0
Derivative liabilities
Long-term Debt, Fair Value	8,300,000,000	7,500,000,000
Long-term Debt, Book Value	8,000,000,000	7,200,000,000
Fair Value, Measurements, Recurring [Member]
Derivative assets
Commodity contracts - financial	23,404,000	17,255,000
Commodity contracts - physical	7,395,000	9,922,000
Interest-rate contracts		2,288,000
Total derivatives assets	30,799,000	29,465,000
Other
Available-for-sale investment securities		1,773,000
Total assets		31,238,000
Derivative liabilities
Commodity contracts - financial	0	0
Commodity contracts - physical		-23,000
Interest-rate contracts	-9,947,000	-44,843,000
Total derivative liabilities	-9,947,000	-44,866,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative assets
Commodity contracts - financial	38,445,000	42,880,000
Commodity contracts - physical	0	0
Interest-rate contracts		0
Total derivatives assets	38,445,000	42,880,000
Other
Available-for-sale investment securities		1,773,000
Total assets		44,653,000
Derivative liabilities
Commodity contracts - financial	-231,000	-169,000
Commodity contracts - physical		0
Interest-rate contracts	0	0
Total derivative liabilities	-231,000	-169,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative assets
Commodity contracts - financial	0	0
Commodity contracts - physical	0	0
Interest-rate contracts		2,288,000
Total derivatives assets	0	2,288,000
Other
Available-for-sale investment securities		0
Total assets		2,288,000
Derivative liabilities
Commodity contracts - financial	0	0
Commodity contracts - physical		0
Interest-rate contracts	-9,947,000	-44,843,000
Total derivative liabilities	-9,947,000	-44,843,000
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Derivative assets
Commodity contracts - financial	3,183,000	354,000
Commodity contracts - physical	7,395,000	9,922,000
Interest-rate contracts		0
Total derivatives assets	10,578,000	10,276,000
Other
Available-for-sale investment securities		0
Total assets		10,276,000
Derivative liabilities
Commodity contracts - financial	-3,538,000	-968,000
Commodity contracts - physical		-23,000
Interest-rate contracts	0	0
Total derivative liabilities	-3,538,000	-991,000
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Derivative assets
Commodity contracts - financial	41,628,000	43,234,000
Commodity contracts - physical	7,395,000	9,922,000
Interest-rate contracts		2,288,000
Total derivatives assets	49,023,000	55,444,000
Other
Available-for-sale investment securities		1,773,000
Total assets		57,217,000
Derivative liabilities
Commodity contracts - financial	-3,769,000	-1,137,000
Commodity contracts - physical		-23,000
Interest-rate contracts	-9,947,000	-44,843,000
Total derivative liabilities	-13,716,000	-46,003,000
Fair Value, Measurements, Recurring [Member] | Netting [Member]
Derivative assets
Commodity contracts - financial	-18,224,000	-25,979,000
Commodity contracts - physical	0	0
Interest-rate contracts		0
Total derivatives assets	-18,224,000	-25,979,000
Other
Available-for-sale investment securities		0
Total assets		-25,979,000
Derivative liabilities
Commodity contracts - financial	3,769,000	1,137,000
Commodity contracts - physical		0
Interest-rate contracts	0	0
Total derivative liabilities	$3,769,000	$1,137,000

FAIR_VALUE_MEASUREMENTS_Part_2

FAIR VALUE MEASUREMENTS - Part 2 (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Transfers Between Levels	$0	$0
Derivative Financial Instruments Assets Liabilities Net [Member]
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Net assets (liabilities) at beginning of period	9,285,000	-782,000
Total realized/unrealized gains (losses):
Included in earnings	269,000	-928,000
Included in other comprehensive income (loss)	-2,514,000	-52,000
Purchases, issuances and settlements	0	3,734,000
Net assets (liabilities) at end of period	$7,040,000	$1,972,000

RISK_MANAGEMENT_AND_HEDGING_AC3

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES Part 1 (Details) (USD $)	Mar. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Derivative, Net Liability Position, Aggregate Fair Value	$0
Assets	49,023,000	55,444,000
Liabilities	-13,716,000	-46,003,000
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Assets	48,448,000	55,444,000
Liabilities	-13,512,000	-45,980,000
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Assets	575,000	0
Liabilities	-204,000	-23,000
Commodity Contract [Member] | Designated as Hedging Instrument [Member] | Physical Derivative Instrument [Member]
Derivatives, Fair Value [Line Items]
Assets	7,395,000	9,922,000
Liabilities	0	0
Commodity Contract [Member] | Designated as Hedging Instrument [Member] | Financial Derivative Instrument [Member]
Derivatives, Fair Value [Line Items]
Assets	41,053,000	43,234,000
Liabilities	-3,565,000	-1,137,000
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Assets	0	2,288,000
Liabilities	-9,947,000	-44,843,000
Physical Derivative Instrument [Member] | Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Assets	0	0
Liabilities	0	-23,000
Financial Derivative Instrument [Member] | Commodity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Assets	575,000	0
Liabilities	-204,000	0
Cash Flow Hedging [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Price Risk Cash Flow Hedge Unrealized Gain (Loss) to be Reclassified During Next 12 Months	$11,300,000

RISK_MANAGEMENT_AND_HEDGING_AC4

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES Part 2 (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Dec. 31, 2014
		MMBbls
Derivative [Line Items]
Notional Amount Of Cash Flow Hedge Instruments Settled	$500,000,000
Not Designated as Hedging Instrument [Member] | Fixed Price [Member] | Sold [Member] | Crude oil and NGLs [Member] | Futures, forwards and swaps [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	-0.6	0
Not Designated as Hedging Instrument [Member] | Fixed Price [Member] | Purchased [Member] | Crude oil and NGLs [Member] | Futures, forwards and swaps [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0.6	0
Designated as Hedging Instrument [Member] | Sold [Member] | Forward Starting Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	0	0
Designated as Hedging Instrument [Member] | Fixed Price [Member] | Sold [Member] | Natural Gas [Member] | Futures and swaps [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	-45,500	-41,200
Designated as Hedging Instrument [Member] | Fixed Price [Member] | Sold [Member] | Crude oil and NGLs [Member] | Futures, forwards and swaps [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	-4.1	-0.5
Designated as Hedging Instrument [Member] | Fixed Price [Member] | Purchased [Member] | Natural Gas [Member] | Futures and swaps [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	0
Designated as Hedging Instrument [Member] | Fixed Price [Member] | Purchased [Member] | Crude oil and NGLs [Member] | Futures, forwards and swaps [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	0
Designated as Hedging Instrument [Member] | Basis [Member] | Sold [Member] | Natural Gas [Member] | Futures and swaps [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	-45,500	-41,200
Designated as Hedging Instrument [Member] | Basis [Member] | Purchased [Member] | Natural Gas [Member] | Futures and swaps [Member]
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount	0	0
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Purchased [Member] | Forward Starting Interest Rate Swap [Member]
Derivative [Line Items]
Notional Amount Of Cash Flow Hedge Instruments Greater Than 12 Months	400,000,000
Derivative, Notional Amount	400,000,000	900,000,000
Natural Gas Pipelines [Member]
Derivative [Line Items]
Derivative, Fair Value, Net	0	0
Natural Gas Liquids [Member]
Derivative [Line Items]
Derivative, Fair Value, Net	$0	0

RISK_MANAGEMENT_AND_HEDGING_AC5

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES Part 3 (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Realized Loss On Settled Interest Rate Swaps Recorded in AOCI	$55,100,000
Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion)	-2,864,000
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	0	-4,600,000
Gain (Loss) on Discontinuation of Interest Rate Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Tax		3,100,000
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income on derivatives (effective portion)	10,455,000	-50,543,000
Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion)	-12,557,000	-60,152,000
Commodity Contract [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Commodity cash flow hedge gain to be reclassified	11,500,000
Price Risk Cash Flow Hedge Unrealized Gain (Loss) to be Reclassified During Next 12 Months	11,300,000
Commodity Cash Flow Hedge Gain To Be Reclassified After Next 12 Months Net	200,000
Interest Rate Contract [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of accumulated other comprehensive income (loss) attributable primarily to settled interest-rate swaps.	-50,100,000
Amount of loss to be recognized in the next 12 months	-5,800,000
Discontinued Operations [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income on derivatives (effective portion)	0	-12,803,000
Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion)	0	-3,697,000
Discontinued Operations [Member] | Commodity Contract [Member] | Revenues [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income on derivatives (effective portion)	0	-12,803,000
Continuing Operations [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income on derivatives (effective portion)	10,455,000	-37,740,000
Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion)	-12,557,000	-56,455,000
Continuing Operations [Member] | Commodity Contract [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion)	10,019,000	-35,762,000
Continuing Operations [Member] | Commodity Contract [Member] | Revenues [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income on derivatives (effective portion)	14,172,000	-26,419,000
Continuing Operations [Member] | Interest Rate Contract [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion)	-22,576,000	-20,693,000
Continuing Operations [Member] | Interest Rate Contract [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income on derivatives (effective portion)	($3,717,000)	($11,321,000)

CREDIT_FACILITIES_AND_SHORTTER1

CREDIT FACILITIES AND SHORT-TERM NOTES PAYABLE (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
ONEOK Credit Agreement [Member]
Line of Credit Facility [Line Items]
Line Of Credit Facility Option To Increase Borrowing Capacity	$500,000,000
Letters of credit issued	1,800,000
Interest rate description	borrowings, if any, will accrue at LIBOR plus 125 basis points
Line Of Credit Facility, Annual Facility Fee Description	the annual facility fee is 25 basis points
Indebtedness To Adjusted EBITDA Maximum	4
Indebtedness To Adjusted EBITDA Current	2.2
Partnership Credit Agreement sublimit for issuance of standby letters of credit	50,000,000
line of credit facility swingline subfacility	50,000,000
Maximum borrowing capacity	300,000,000
Write off of Deferred Debt Issuance Cost		2,900,000
Short-term Bank Loans and Notes Payable	0
Partnership Credit Agreement [Member]
Line of Credit Facility [Line Items]
Commercial paper	825,500,000
Letters of credit issued	14,000,000
Total short-term borrowings authorized by our general partner's Board of Directors	2,500,000,000
Interest rate description	borrowings, if any, will accrue at LIBOR plus 117.5 basis points
Line Of Credit Facility, Annual Facility Fee Description	the annual facility fee is 20 basis points
Indebtedness To Adjusted EBITDA Maximum	5
Acquisition price threshold for increase in permitted debt to EBITDA covenant ratio	25,000,000
Indebtedness To Adjusted EBITDA From Acquisitions Maximum	5.5
Indebtedness To Adjusted EBITDA Current	4.5
Partnership Credit Agreement sublimit for issuance of standby letters of credit	100,000,000
line of credit facility swingline subfacility	150,000,000
Maximum borrowing capacity	2,400,000,000		1,700,000,000
Maximum Amount Of Commercial Paper	2,400,000,000		1,700,000,000
Short-term Bank Loans and Notes Payable	$0

LONGTERM_DEBT_Details

LONG-TERM DEBT (Details) (USD $)	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2015	Jan. 31, 2014
Debt Instrument [Line Items]
Related Party Transaction, Amounts of Transaction	$1,130,000,000
Loss on extinguishment of debt	24,800,000
Note Payable from Public Offering Due 2022 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount	152,500,000
Debt Instrument, Interest Rate, Stated Percentage	4.25%
Early Repayment of Senior Debt	150,000,000
Note Payable due 2015 [Member]
Debt Instrument [Line Items]
Extinguishment of Debt, Amount	400,000,000
Debt Instrument, Interest Rate, Stated Percentage	5.20%
Early Repayment of Senior Debt	430,100,000
ONE Gas [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			1,200,000,000
Proceeds from Debt, Net of Issuance Costs	1,190,000,000
ONE Gas [Member] | Notes Payable due 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			2.07%
Long-term Debt, Gross			300,000,000
ONE Gas [Member] | Notes Payable due 2024 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			3.61%
Long-term Debt, Gross			300,000,000
ONE Gas [Member] | Notes Payable due 2044 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			4.66%
Long-term Debt, Gross			600,000,000
Partnership Interest [Member] | Note Payable from Public Offering Due 2020 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.80%
Long-term Debt, Gross		300,000,000
Partnership Interest [Member] | Note Payable from Public Offering Due 2025 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		4.90%
Long-term Debt, Gross		500,000,000
Partnership Interest [Member] | Note Payable from Public Offering Due 2016 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage		3.25%
Long-term Debt, Gross		650,000,000
Senior Notes [Member] | Partnership Interest [Member]
Debt Instrument [Line Items]
Debt Instrument, Call Feature		ONEOK Partners may redeem its 3.8 percent senior notes due 2020 and its 4.9 percent senior notes due 2025 from the March 2015 offering at par, plus accrued and unpaid interest to the redemption date, starting one month and three months, respectively, before their maturity dates. Prior to these dates, ONEOK Partners may redeem these 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. ONEOK Partnersb senior notes are senior unsecured obligations, ranking equally in right of payment with all of ONEOK Partnersb existing and future unsecured senior indebtedness, and structurally subordinate to any of the existing and future debt and other liabilities of any ONEOK Partnersb nonguarantor subsidiaries.
Debt Instrument, Covenant Description		These notes are governed by an indenture, dated as of September 25, 2006, between ONEOK Partners and Wells Fargo Bank, N.A., the trustee, as supplemented. The indenture does not limit the aggregate principal amount of debt securities that may be issued and provides that debt securities may be issued from time to time in one or more additional series. The indenture contains covenants including, among other provisions, limitations on ONEOK Partnersb ability to place liens on its property or assets and to sell and lease back its property. The indenture includes an event of default upon acceleration of other indebtedness of $100 million or more. Such events of default would entitle the trustee or the holders of 25 percent in aggregate principal amount of any of ONEOK Partnersb outstanding senior notes to declare those notes immediately due and payable in full.
Senior Notes, Noncurrent		800,000,000
Proceeds from Debt, Net of Issuance Costs		$792,300,000

EQUITY_Details

EQUITY (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Jun. 30, 2015
Common Stock, Dividends, Per Share, Cash Paid	$0.61
Stockholders' equity, beginning balance	$4,005,883	$4,845,180
Net income	95,693	206,511
Other comprehensive income (loss)	-18,625	-8,624
Common stock issued	3,800	7,579
Common stock dividends	-126,053	-83,275
Issuance of common units of ONEOK Partners	66,273	52,842
Distribution of ONE Gas to shareholders	0	-1,747,424
Distributions to noncontrolling interests	-129,457	-101,655
Other	-4,226	-43,427
Stockholders' equity, ending balance	3,893,288	3,127,707
Dividends declared per share of common stock	$0.61	$0.40
ONEOK Shareholders' Equity [Member]
Stockholders' equity, beginning balance	592,115	2,337,851
Net income	60,800	93,515
Other comprehensive income (loss)	-3,539	8,685
Common stock issued	3,800	7,579
Common stock dividends	-126,053	-83,275
Issuance of common units of ONEOK Partners	7,261	10,996
Distribution of ONE Gas to shareholders	0	-1,747,424
Distributions to noncontrolling interests	0	0
Other	-4,226	-43,427
Stockholders' equity, ending balance	530,158	584,500
Noncontrolling Interests in Consolidated Subsidiaries [Member]
Stockholders' equity, beginning balance	3,413,768	2,507,329
Net income	34,893	112,996
Other comprehensive income (loss)	-15,086	-17,309
Common stock issued	0	0
Common stock dividends	0	0
Issuance of common units of ONEOK Partners	59,012	41,846
Distribution of ONE Gas to shareholders	0	0
Distributions to noncontrolling interests	-129,457	-101,655
Other	0	0
Stockholders' equity, ending balance	$3,363,130	$2,543,207
Subsequent Event [Member]
Dividends declared per share of common stock			$0.61
Dividends Payable, Date of Record			30-Apr-15
Dividends Payable, Date to be Paid			15-May-15

ACCUMULATED_OTHER_COMPREHENSIV2

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax	($42,371)		($37,349)
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax	0		955
Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax	-97,521		-99,959
Accumulated Other Comprehensive Income (Loss), Net of Tax	-139,892		-136,353
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	-2,864
Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, before Reclassification Adjustments, Net of Tax	-955
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, before Reclassification Adjustments, Net of Tax	19
Other comprehensive income (loss) before reclassifications	-3,800
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	-9,230	37,527
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Sale of Securities, Net of Tax	0
Other Comprehensive Income (Loss), Reclassification Adjustment included in Net Income, Net of Tax	261	24,224
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent	-5,022
Other Comprehensive Income (Loss), Unrealized Holding Gain (Loss) on Securities Arising During Period, Net of Tax	-955	-76
Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax	2,438	3,851
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent	-3,539
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	1,225	-13,017
Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	-2,158	20,418
Accumulated Defined Benefit Plans Adjustment [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax	2,419	3,806
Defined Benefit Plan, Future Amortization of Gain (Loss)	4,423	3,963
Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit)	-392	367
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax	4,031	3,596
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Tax	-1,612	-1,438
Total before tax [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	-10,455	37,740
Tax benefit [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	1,225	-7,896
Continuing Operations [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	-9,230	29,844
Continuing Operations [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax	2,419	2,158
Discontinued Operations [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	0	7,683
Discontinued Operations [Member] | Accumulated Defined Benefit Plans Adjustment [Member]
Other Comprehensive (Income) Loss, Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, Net of Tax	0	1,648
Net of tax [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	-9,230	37,527
Net income attributable to noncontrolling interest [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Noncontrolling Interest	-7,072	17,109
Commodity Contract [Member] | Sales [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	-14,172	26,419
Interest Rate Contract [Member] | Interest Expense [Member] | Accumulated Net Gain (Loss) from Designated or Qualifying Cash Flow Hedges [Member]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$3,717	$11,321

EARNINGS_PER_SHARE_Details

EARNINGS PER SHARE (Details) (USD $)	3 Months Ended
In Thousands, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Basic EPS from continuing operations [Abstract]
Income from continuing operations attributable to ONEOK available for common stock	$60,944	$91,741
Weighted Average number of share, basic (in shares)	209,874	209,130
Per share amount, basic (in dollars per shares)	$0.29	$0.44
Diluted EPS from continuing operations [Abstract]
Effect of dilutive securities	0	0
Effect of dilutive securities, number of shares (in shares)	593	1,036
Income from continuing operations attributable to ONEOK available for common stock and common stock equivalents	$60,944	$91,741
Weighted Average number of share, diluted (in shares)	210,467	210,166
Per Share amount, diluted (in dollars per share)	$0.29	$0.44
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount	0	0

EMPLOYEE_BENEFIT_PLANS_Details

EMPLOYEE BENEFIT PLANS (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014
Pension Benefits [Member]
Components of net periodic benefit cost
Service cost	$1,887	$1,822
Interest cost	4,546	4,628
Expected return on assets	-5,213	-4,935
Amortization of unrecognized prior service cost	23	48
Amortization of net loss	3,987	3,755
Net periodic benefit cost	5,230	5,318
Postretirement Benefits [Member]
Components of net periodic benefit cost
Service cost	186	179
Interest cost	586	611
Expected return on assets	-564	-555
Amortization of unrecognized prior service cost	-415	-415
Amortization of net loss	436	208
Net periodic benefit cost	$229	$28

UNCONSOLIDATED_AFFILIATES_Deta

UNCONSOLIDATED AFFILIATES (Details) (USD $)	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Schedule of Equity Method Investments [Line Items]
Equity in net earnings from investments	$30,921,000	$33,659,000
Investments in unconsolidated affiliates	1,124,204,000	1,229,054,000	1,132,653,000
Accounts Payable, Related Parties, Current	7,400,000		20,500,000
Income Statement
Operating revenues	129,581,000	155,279,000
Operating expenses	57,579,000	71,679,000
Net income	66,359,000	78,673,000
Distributions paid to ONEOK Partners	39,429,000	35,070,000
Northern Border Pipeline [Member]
Schedule of Equity Method Investments [Line Items]
Equity in net earnings from investments	19,702,000	23,409,000
Overland Pass Pipeline Company [Member]
Schedule of Equity Method Investments [Line Items]
Equity in net earnings from investments	6,887,000	4,731,000
Other Unconsolidated Affiliate [Member]
Schedule of Equity Method Investments [Line Items]
Equity in net earnings from investments	4,332,000	5,519,000
Unconsolidated Affiliates [Member]
Schedule of Equity Method Investments [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	19,900,000	14,200,000
Powder River Basin [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	215,300,000
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity	$130,500,000

ONEOK_PARTNERS_Details

ONEOK PARTNERS (Details) (USD $)	3 Months Ended		12 Months Ended
Share data in Millions, except Per Share data, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Related Party Transaction [Line Items]
Key Provisions of Operating or Partnership Agreement, Description	Cash Distributions - We receive distributions from ONEOK Partners on our common and Class B units and our 2 percent general partner interest, which includes our incentive distribution rights. Under ONEOK Partnersb partnership agreement, as amended, distributions are made to the partners with respect to each calendar quarter in an amount equal to 100 percent of available cash as defined in the Partnership Agreement, as amended. Available cash generally will be distributed 98 percent to limited partners and 2 percent to the general partner. The general partnerbs percentage interest in quarterly distributions is increased after certain specified target levels are met during the quarter. Under the incentive distribution provisions, as set forth in the Partnership Agreement the general partner receives: 15 percent of amounts distributed in excess of $0.3025 per unit; 25 percent of amounts distributed in excess of $0.3575 per unit; and 50 percent of amounts distributed in excess of $0.4675 per unit.
AggregateAmountOfCommonUnitsAvailableForIssuanceAndSaleUnderEquityDistributionAgreement	$650,000,000
Remaining Capacity of At The Market Equity Program	443,000,000
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	37.60%		37.80%
Common units	19.8
Class B units	73
Issuance of common units of ONEOK Partners	66,273,000	52,842,000
Partners capital account units sold under equity distribution agreement	1.7	1.1
General Partner [Member]
Related Party Transaction [Line Items]
Limited Liability Company (LLC) or Limited Partnership (LP), Managing Member or General Partner, Ownership Interest	2.00%
Limited Partner [Member]
Related Party Transaction [Line Items]
Ownership interest (in hundreths)	35.60%
Distribution Paid [Member]
Related Party Transaction [Line Items]
Distribution per unit	$0.79	$0.73
Distributions to general partner	95,193,000	73,104,000
Total distributions	295,706,000	242,496,000
Distribution Paid [Member] | ONEOK [Member]
Related Party Transaction [Line Items]
Limited partner distributions to ONEOK	73,302,000	67,737,000
Distribution Paid [Member] | General Partner [Member]
Related Party Transaction [Line Items]
General partner distributions	5,914,000	4,849,000
Incentive distributions	89,279,000	68,255,000
Distribution Paid [Member] | Limited Partner [Member]
Related Party Transaction [Line Items]
Limited partner distributions to noncontrolling interest	127,211,000	101,655,000
Distribution Declared [Member]
Related Party Transaction [Line Items]
Distribution per unit	$0.79	$0.75
Distribution Made To Member Or Limited Parter Annualized Quarterly Distribution	3.16
Distributions to general partner	95,844,000	76,922,000
Total distributions	297,729,000	250,555,000
Distribution Made to Limited Partner, Date of Record	30-Apr-15
Distribution Made to Limited Partner, Distribution Date	15-May-15
Distribution Declared [Member] | ONEOK [Member]
Related Party Transaction [Line Items]
Limited partner distributions to ONEOK	73,302,000	69,127,000
Distribution Declared [Member] | General Partner [Member]
Related Party Transaction [Line Items]
General partner distributions	5,955,000	5,011,000
Incentive distributions	89,889,000	71,911,000
Distribution Declared [Member] | Limited Partner [Member]
Related Party Transaction [Line Items]
Limited partner distributions to noncontrolling interest	128,583,000	104,506,000
Paid-in Capital [Member]
Related Party Transaction [Line Items]
Issuance of common units of ONEOK Partners	7,261,000
Issued Under Equity Distribution Agreement [Member]
Related Party Transaction [Line Items]
Proceeds from Sale of Interest in Partnership Unit	71,600,000	56,500,000
ONEOK [Member]
Related Party Transaction [Line Items]
Revenue	0	53,526,000
Expenses
Cost of sales and fuel	0	10,835,000
Administrative and general expenses	89,528,000	77,246,000
Total expenses	89,528,000	88,081,000
West Texas LPG and Mesquite Systems [Member]
Related Party Transaction [Line Items]
Business Acquisition, Effective Date of Acquisition			28-Nov-14
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest			800,000,000
West Texas LPG Pipeline Limited Partnership [Member]
Expenses
Business Acquisition, Description of Acquired Entity			80 percent interest
Mesquite Pipeline [Member]
Related Party Transaction [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired			100.00%

SEGMENTS_Details

SEGMENTS (Details) (USD $)	3 Months Ended
In Thousands, unless otherwise specified	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Segment Reporting Information [Line Items]
Segment Reporting, Disclosure of Major Customers	ONEOK Partners had one customer, BP p.l.c., from which it received $184.9 million in total revenues from all of the operating segments, or approximately 10 percent of our consolidated revenues.	ONEOK Partners had no single customer from which it received 10 percent or more of our consolidated revenues.
Total revenues	$1,805,306	$3,163,296
Net margin	461,442	510,627
Operating costs	179,018	149,111
Depreciation and amortization	85,955	67,414
Gain (loss) on sale of assets	-6	15
Operating income	196,463	294,117
Equity in net earnings from investments	30,921	33,659
Investments in unconsolidated affiliates	1,124,204	1,229,054	1,132,653
Total assets	15,533,073	13,653,134	15,304,560
Noncontrolling interests in consolidated subsidiaries	3,363,130	2,543,207	3,413,768
Capital expenditures	343,847	429,525
Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Total revenues	455,623	762,125
Net margin	124,692	153,554
Operating costs	69,209	64,824
Depreciation and amortization	35,797	28,842
Gain (loss) on sale of assets	1	-19
Operating income	19,687	59,869
Equity in net earnings from investments	4,239	5,486
Investments in unconsolidated affiliates	255,419	333,054
Total assets	4,887,940	4,048,332
Noncontrolling interests in consolidated subsidiaries	4,156	4,597
Capital expenditures	255,301	122,891
Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Total revenues	1,496,092	2,711,812
Net margin	267,227	268,978
Operating costs	82,246	65,102
Depreciation and amortization	39,294	27,078
Gain (loss) on sale of assets	-8	-48
Operating income	145,679	176,750
Equity in net earnings from investments	6,980	4,764
Investments in unconsolidated affiliates	483,257	489,120
Total assets	8,106,767	6,861,829
Noncontrolling interests in consolidated subsidiaries	162,958	0
Capital expenditures	73,466	273,063
Natural Gas Liquids [Member] | Natural Gas Liquids for Regulated Segment [Member]
Segment Reporting Information [Line Items]
Total revenues	209,800	135,800
Net margin	124,100	84,700
Operating income	64,900	45,100
Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Total revenues	83,549	104,793
Net margin	69,123	93,489
Operating costs	27,242	27,462
Depreciation and amortization	10,756	10,815
Gain (loss) on sale of assets	1	-83
Operating income	31,126	55,129
Equity in net earnings from investments	19,702	23,409
Investments in unconsolidated affiliates	385,528	406,880
Total assets	1,807,978	1,848,594
Noncontrolling interests in consolidated subsidiaries	0	0
Capital expenditures	9,592	6,627
Natural Gas Pipelines [Member] | Natural Gas Pipelines for Regulated Segment [Member]
Segment Reporting Information [Line Items]
Total revenues	69,300	81,300
Net margin	60,900	68,600
Operating income	27,400	35,100
Corporate Elimination [Member]
Segment Reporting Information [Line Items]
Total revenues	-229,958	-415,434
Net margin	400	-5,394
Operating costs	321	-8,277
Depreciation and amortization	108	679
Gain (loss) on sale of assets	0	165
Operating income	-29	2,369
Equity in net earnings from investments	0	0
Investments in unconsolidated affiliates	0	0
Total assets	730,388	894,379
Noncontrolling interests in consolidated subsidiaries	3,196,016	2,538,610
Capital expenditures	5,488	26,944
Discontinued Operations [Member] | Corporate Elimination [Member]
Segment Reporting Information [Line Items]
Total assets	36,800	179,600
Capital expenditures		23,900
Sales to unaffiliated customers
Segment Reporting Information [Line Items]
Total revenues	1,805,306	3,109,770
Sales to unaffiliated customers | Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Total revenues	288,016	347,016
Sales to unaffiliated customers | Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Total revenues	1,434,813	2,670,655
Sales to unaffiliated customers | Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Total revenues	81,930	91,106
Sales to unaffiliated customers | Corporate Elimination [Member]
Segment Reporting Information [Line Items]
Total revenues	547	993
Sales to affiliated customers
Segment Reporting Information [Line Items]
Total revenues		53,526
Sales to affiliated customers | Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Total revenues		41,214
Sales to affiliated customers | Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Total revenues		0
Sales to affiliated customers | Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Total revenues		12,312
Sales to affiliated customers | Corporate Elimination [Member]
Segment Reporting Information [Line Items]
Total revenues		0
Intersegment revenues
Segment Reporting Information [Line Items]
Total revenues	0	0
Intersegment revenues | Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Total revenues	167,607	373,895
Intersegment revenues | Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Total revenues	61,279	41,157
Intersegment revenues | Natural Gas Liquids [Member] | Natural Gas Liquids for Regulated Segment [Member]
Segment Reporting Information [Line Items]
Total revenues	165,300	111,600
Intersegment revenues | Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Total revenues	1,619	1,375
Intersegment revenues | Corporate Elimination [Member]
Segment Reporting Information [Line Items]
Total revenues	($230,505)	($416,427)