ONEOK Partners (OKS) 10-Q 4 May 16 2016 Q1 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2016	Apr. 25, 2016
Document Information [Line Items]
Entity Registrant Name	ONEOK Partners LP
Entity Central Index Key	909,281
Current Fiscal Year End Date	--12-31
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Document Fiscal Year Focus	2,016
Document Fiscal Period Focus	Q1
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Mar. 31, 2016
Common Units [Member]
Document Information [Line Items]
Limited Partners' Capital Account, Units Outstanding		212,837,980
Class B Units [Member]
Document Information [Line Items]
Limited Partners' Capital Account, Units Outstanding		72,988,252

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Revenues
Commodity sales	$ 1,283,511	$ 1,435,716
Services	490,434	369,043
Total revenues	1,773,945	1,804,759
Cost of sales and fuel (exclusive of items shown separately below)	1,195,738	1,343,864
Operations and maintenance	148,740	153,675
Depreciation and amortization	93,736	85,847
General taxes	21,640	24,484
(Gain) loss on sale of assets	(4,145)	6
Operating income	318,236	196,883
Equity in net earnings from investments (Note I)	32,914	30,921
Allowance for equity funds used during construction	208	799
Other income	145	3,049
Other expense	(634)	(1,151)
Interest expense (net of capitalized interest of $2,887 and $7,230, respectively)	(92,555)	(80,709)
Income before income taxes	258,314	149,792
Income taxes	(2,028)	(2,760)
Net income	256,286	147,032
Less: Net income attributable to noncontrolling interests	2,769	1,438
Net income attributable to ONEOK Partners, L.P.	253,517	145,594
Limited partners' interest in net income:
Net income attributable to ONEOK Partners, L.P.	253,517	145,594
General partner's interest in net income	(105,608)	(92,801)
Limited partners' interest in net income	$ 147,909	$ 52,793
Limited partners' net income per unit, basic and diluted (Note H)	$ 0.52	$ 0.21
Number of units used in computation (thousands)	285,826	254,075

CONSOLIDATED STATEMENT OF INCOM

CONSOLIDATED STATEMENT OF INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Limited partners' net income per unit, diluted	$ 0.52	$ 0.21
Interest Costs, Capitalized During Period	$ 2,887	$ 7,230

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Net income	$ 256,286	$ 147,032
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives	(19,933)	(12,557)
Realized (gains) losses on derivatives recognized in net income	(10,680)	(11,333)
Other comprehensive income (loss) on investment in unconsolidated affiliates	(5,801)	0
Total other comprehensive income (loss)	(36,414)	(23,890)
Comprehensive income	219,872	123,142
Less: Comprehensive income attributable to noncontrolling interests	2,769	1,438
Comprehensive income attributable to ONEOK Partners, L.P.	$ 217,103	$ 121,704

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 9,882	$ 5,079
Accounts receivable, net	520,800	593,448
Affiliate receivables	3,563	7,969
Natural gas and natural gas liquids in storage	156,075	128,084
Commodity imbalances	38,742	38,681
Materials and supplies	83,144	76,696
Other current assets	44,256	33,207
Total current assets	856,462	883,164
Property, plant and equipment
Property, plant and equipment	14,448,918	14,307,546
Accumulated depreciation and amortization	2,126,432	2,050,755
Net property, plant and equipment	12,322,486	12,256,791
Investments and other assets
Investments in unconsolidated affiliates	929,209	948,221
Goodwill and intangible assets	821,902	824,877
Other assets	14,663	14,533
Total investments and other assets	1,765,774	1,787,631
Total assets	14,944,722	14,927,586
Current liabilities
Current maturities of long-term debt (Note E)	457,650	107,650
Short-term borrowings (Note D)	444,567	546,340
Accounts payable	513,453	605,431
Affiliate payables	20,070	27,137
Commodity imbalances	77,489	74,460
Accrued interest	86,718	102,615
Other current liabilities	109,341	116,667
Total current liabilities	1,709,288	1,580,300
Long-term debt, excluding current maturities	6,692,238	6,695,312
Deferred credits and other liabilities	$ 165,522	$ 154,631
Commitments and contingencies (Note K)
ONEOK Partners, L.P. partners' equity:
General partner	$ 229,754	$ 231,344
Common units: 212,837,980 units issued and outstanding at March 31, 2016, and December 31, 2015	4,956,949	5,014,952
Class B units: 72,988,252 units issued and outstanding at March 31, 2016, and December 31, 2015	1,180,313	1,200,204
Accumulated other comprehensive loss (Note G)	(149,696)	(113,282)
Total ONEOK Partners, L.P. partners' equity	6,217,320	6,333,218
Noncontrolling interests in consolidated subsidiaries	160,354	164,125
Total equity	6,377,674	6,497,343
Total liabilities and equity	$ 14,944,722	$ 14,927,586

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Mar. 31, 2016	Dec. 31, 2015
ONEOK Partners, L.P. partners equity:
Common units issued (in shares)	212,837,980	212,837,980
Common units outstanding (in shares)	212,837,980	212,837,980
Class B units issued (in shares)	72,988,252	72,988,252
Class B units outstanding (in shares)	72,988,252	72,988,252

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Operating activities
Net income	$ 256,286	$ 147,032
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	93,736	85,847
Allowance for equity funds used during construction	(208)	(799)
(Gain) loss on sale of assets	(4,145)	6
Deferred income taxes	2,254	2,130
Equity in net earnings from investments	(32,914)	(30,921)
Distributions received from unconsolidated affiliates	34,789	29,475
Changes in assets and liabilities:
Accounts receivable	68,618	128,176
Affiliate receivables	4,406	2,021
Natural gas and natural gas liquids in storage	(27,991)	(84,557)
Accounts payable	(62,401)	(118,899)
Affiliate payables	(7,067)	(6,775)
Commodity imbalances, net	2,968	15,057
Accrued interest	(15,897)	(3,020)
Risk-management assets and liabilities	(24,691)	(60,143)
Other assets and liabilities, net	(21,490)	(39,513)
Cash provided by operating activities	266,253	65,117
Investing activities
Capital expenditures (less allowance for equity funds used during construction)	(195,896)	(343,036)
Contributions to unconsolidated affiliates	(158)	0
Distributions received from unconsolidated affiliates in excess of cumulative earnings	11,764	9,954
Proceeds from sale of assets	14,797	118
Cash used in investing activities	(169,493)	(332,964)
Financing activities
Cash distributions paid to general and limited partners	(333,001)	(295,706)
Cash distributions paid to noncontrolling interests	(2,500)	(2,246)
Borrowing (repayment) of short-term borrowings, net	(101,773)	(229,821)
Issuance of long-term debt, net of discounts	1,000,000	798,896
Debt financing costs	(2,770)	(7,850)
Repayment of long-term debt	(651,913)	(1,913)
Issuance of common units, net of issuance costs	0	53,388
Contribution from general partner	0	1,100
Cash provided by (used in) financing activities	(91,957)	315,848
Change in cash and cash equivalents	4,803	48,001
Cash and cash equivalents at beginning of period	5,079	42,530
Cash and cash equivalents at end of period	$ 9,882	$ 90,531

CONSOLIDATED STATEMENT OF CHANG

CONSOLIDATED STATEMENT OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Common Units [Member]	Class B Units [Member]	General Partner [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Noncontrolling Interests in Consolidated Subsidiaries [Member]
Partners capital account, units, beginning balance at Dec. 31, 2014		180,826,973	72,988,252
Partners capital account, beginning balance at Dec. 31, 2014	$ 6,118,775	$ 4,456,372	$ 1,374,375	$ 211,914	$ (91,823)	$ 167,937
Net income	147,032	37,582	15,211	92,801	0	1,438
Other comprehensive income (loss) (Note G)	(23,890)	$ 0	$ 0	0	(23,890)	0
Issuance of common units (in units) (Note F)		1,736,148	0
Issuance of common units (Note F)	70,537	$ 70,537	$ 0	0	0	0
Contribution from general partner (Note F)	1,100	0	0	1,100	0	0
Distributions paid (Note F)	(297,952)	$ (142,853)	$ (57,660)	(95,193)	0	(2,246)
Partners capital account, units, ending balance at Mar. 31, 2015		182,563,121	72,988,252
Partners capital account, ending balance at Mar. 31, 2015	6,015,602	$ 4,421,638	$ 1,331,926	210,622	(115,713)	167,129
Partners capital account, units, beginning balance at Dec. 31, 2014		180,826,973	72,988,252
Partners capital account, beginning balance at Dec. 31, 2014	6,118,775	$ 4,456,372	$ 1,374,375	211,914	(91,823)	167,937
Partners capital account, units, ending balance at Dec. 31, 2015		212,837,980	72,988,252
Partners capital account, ending balance at Dec. 31, 2015	6,497,343	$ 5,014,952	$ 1,200,204	231,344	(113,282)	164,125
Net income	256,286	110,140	37,769	105,608	0	2,769
Other comprehensive income (loss) (Note G)	(36,414)	0	0	0	(36,414)	0
Distributions paid (Note F)	(335,501)	(168,143)	(57,660)	(107,198)	0	(2,500)
Other	(4,040)	$ 0	$ 0	0	0	(4,040)
Partners capital account, units, ending balance at Mar. 31, 2016		212,837,980	72,988,252
Partners capital account, ending balance at Mar. 31, 2016	$ 6,377,674	$ 4,956,949	$ 1,180,313	$ 229,754	$ (149,696)	$ 160,354

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	3 Months Ended
	Mar. 31, 2016
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	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 2015 year-end consolidated balance sheet data was derived from our audited financial statements but does not include all disclosures required by GAAP. Certain reclassifications have been made in the prior-year financial statements to conform to the current-year presentation. 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. Recently Issued Accounting Standards Update - In September 2015, the FASB issued ASU 2015-16, “Business Combinations (Topic 805) - Simplifying the Accounting for Measurement-Period Adjustments,” which requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined. The amendment also requires the acquirer to record the income statement effects of changes to provisional amounts in the financial statements in the period in which the adjustments occurred. This guidance was effective for public companies for fiscal years beginning after December 15, 2015. We adopted this guidance in the first quarter 2016, and there was no impact, but it could impact us in the future if we complete any acquisitions with subsequent measurement period adjustments. In April 2015, the FASB issued ASU 2015-05, “Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement,” which clarifies whether a cloud computing arrangement includes a software license. If it does, the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses; if not, the customer should account for the arrangement as a service contract. This guidance was effective for public companies for fiscal years beginning after December 15, 2015. We adopted this guidance in the first quarter 2016. The impact of adopting this guidance was not material. 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 was effective for public companies for fiscal years beginning after December 15, 2015. We adopted this guidance in the first quarter 2016. The impact of adopting this guidance was not material. In March 2016, the FASB issued ASU 2016-06, “Derivatives and Hedging (Topic 815): Contingent Put and Call Options in Debt Instruments,” which clarifies the requirements for assessing whether a contingent call (put) option that can accelerate the payment of principal on a debt instrument is clearly and closely related to its debt host. Under the amendments in the update, assessments must be performed in accordance with the four-step decision sequence to conclude which call (put) options should be bifurcated and accounted for separately as derivatives. This guidance is effective for public companies for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years, with early adoption permitted. We expect to adopt this guidance in the first quarter 2017, and we are evaluating the impact on us. In March 2016, the FASB issued ASU 2016-05, “Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships,” which clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. This guidance is effective for public companies for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. Early adoption is permitted. We expect to adopt this guidance in the first quarter 2017, and we are evaluating the impact on us. In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842),” which requires the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases under previous GAAP. It also requires qualitative disclosures along with specific quantitative disclosures by lessees and lessors to meet the objective of enabling users of financial statements to assess the amount, timing and uncertainty of cash flows arising from leases. This guidance is effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. We expect to adopt this guidance in the first quarter 2019, and we are evaluating the impact on us. In January 2016, the FASB issued ASU 2016-01, “Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities,” which requires all equity investments other than those accounted for using the equity method of accounting or those that result in consolidation of the investee to be measured at fair value with changes in fair value recognized in net income, eliminates the available-for-sale classification for equity securities with readily determinable fair values and eliminates the cost method for equity investments without readily determinable fair values. Additionally, this guidance eliminates the requirement to disclose the methods and significant assumptions used to estimate the fair value of financial instruments carried at amortized cost and requires the use of the exit price when measuring the fair value of such instruments for disclosure purposes. This guidance will be effective for public companies in fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is only permitted for certain portions of the ASU. We expect to adopt this guidance in the first quarter 2018, and we are evaluating the impact on us. In July 2015, the FASB issued ASU 2015-11, “Inventory (Topic 330): Simplifying the Measurement of Inventory,” which requires that inventory, excluding inventory measured using last-in, first-out (LIFO) or the retail inventory method, be measured at the lower of cost or net realizable value. This guidance will be effective for public companies for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. We expect to adopt this guidance in the first quarter 2017, and we are evaluating the impact on us. In August 2014, the FASB issued ASU 2014-15, “Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a 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 expect to adopt this guidance beginning in the fourth 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 (Topic 606),” 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. In August 2015, the FASB issued ASU 2015-14, “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date,” that deferred the effective date of ASU 2014-09 by one year. This update is now effective for interim and annual periods that begin after December 15, 2017, with either retrospective application for all periods presented or retrospective application with a cumulative effect adjustment. The FASB has issued additional ASUs, which provide further guidance and clarification on implementation issues. We expect to adopt this guidance beginning in the first quarter 2018, and we are evaluating the impact on us.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	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 our 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, data obtained from third-party pricing services and LIBOR and other liquid money-market instrument rates. 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 derivative portfolio 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 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-rate 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 natural gas basis and NGL price curves that incorporate observable and unobservable market data from broker quotes, third-party pricing services, 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 has not been 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 the periods indicated: March 31, 2016 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net (b) ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 55,062 $ — $ 6,806 $ 61,868 $ (34,261 ) $ 27,607 Physical contracts — — 1,592 1,592 — 1,592 Total derivative assets $ 55,062 $ — $ 8,398 $ 63,460 $ (34,261 ) $ 29,199 Derivative liabilities Commodity contracts Financial contracts $ (6,451 ) $ — $ (6,424 ) $ (12,875 ) $ 12,855 $ (20 ) Physical contracts — — (1,940 ) (1,940 ) — (1,940 ) Interest-rate contracts — (41,547 ) — (41,547 ) — (41,547 ) Total derivative liabilities $ (6,451 ) $ (41,547 ) $ (8,364 ) $ (56,362 ) $ 12,855 $ (43,507 ) (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 us. At March 31, 2016 , we held $21.4 million of cash from various counterparties and had no cash collateral posted. (b) - Included in other current assets, other current liabilities or deferred credits and other liabilities in our Consolidated Balance Sheets. December 31, 2015 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net (b) ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 38,921 $ — $ 7,253 $ 46,174 $ (42,414 ) $ 3,760 Physical contracts — — 3,591 3,591 — 3,591 Total derivative assets $ 38,921 $ — $ 10,844 $ 49,765 $ (42,414 ) $ 7,351 Derivative liabilities Commodity contracts Financial contracts $ (4,513 ) $ — $ (3,513 ) $ (8,026 ) $ 8,026 $ — Interest-rate contracts — (9,936 ) — (9,936 ) — (9,936 ) Total derivative liabilities $ (4,513 ) $ (9,936 ) $ (3,513 ) $ (17,962 ) $ 8,026 $ (9,936 ) (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 us. At December 31, 2015 , we held $34.4 million of cash from various counterparties and had no cash collateral posted. (b) - Included in other current 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 the periods indicated: Three Months Ended March 31, Derivative Assets (Liabilities) 2016 2015 ( Thousands of dollars ) Net assets at beginning of period $ 7,331 $ 9,285 Total realized/unrealized gains (losses): Included in earnings (a) (745 ) 269 Included in other comprehensive income (loss) (6,552 ) (2,514 ) Net assets at end of period $ 34 $ 7,040 (a) - Included in commodity sales revenues in our Consolidated Statements of Income. Realized/unrealized gains (losses) include the realization of our derivative contracts through maturity. During the three months ended March 31, 2016 and 2015 , 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 each reporting period were not material. We recognize transfers into and out of the levels in the fair value hierarc hy as of the end of each reporting period. During the three months ended March 31, 2016 and 2015 , there were no tra ns fers between levels. Other Financial Instruments - The approximate fair value of cash and cash equivalents, accounts receivable, accounts payable and short-term borrowings 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 short-term borrowings are classified as Level 2 since the estimated fair value of the short-term borrowings can be determined using information available in the commercial paper market. The estimated fair value of the aggregate of our long-term debt, including current maturities, was $6.9 billion and $6.2 billion at March 31, 2016 , and December 31, 2015 , respectively. The book value of the aggregate of our long-term debt, including current maturities, was $7.1 billion and $6.8 billion at March 31, 2016 , and December 31, 2015 , respectively. The estimated fair value of the aggregate of our senior notes outstanding was determined using quoted market prices for similar issues with similar terms and maturities. The estimated fair value of our long-term debt is classified as Level 2.

RISK MANAGEMENT AND HEDGING ACT

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES	RISK-MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES Risk-Management Activities - We are 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. We use physical-forward purchases and sales and financial derivatives to secure a certain price for a portion of our natural gas, condensate and NGL products; to reduce our exposure to commodity price and interest-rate fluctuations; and to achieve more predictable cash flows. We follow established policies and procedures to assess risk and approve, monitor and report our risk-management activities. We have not used these instruments for trading purposes. We are also subject to the risk of interest-rate fluctuation in the normal course of business. Commodity price risk - Commodity price risk refers to the risk of loss in cash flows and future earnings arising from adverse changes in the price of natural gas, NGLs and condensate. We use 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; • 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; and • Options - 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. We may also use other instruments including collars to mitigate commodity price risk. 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. In our Natural Gas Gathering and Processing segment, we are exposed to commodity price risk as a result of receiving commodities as a portion of our compensation for services associated with our POP with fee contracts. Under certain POP with fee contracts, our fee revenues may increase or decrease if production volumes, delivery pressures or commodity prices change relative to specified thresholds. We also are exposed to basis risk between the various production and market locations where we receive and sell commodities. As part of our hedging strategy, we use 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. In our Natural Gas Liquids segment, we are 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. We are 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. We utilize physical-forward contracts and commodity derivative financial instruments to reduce the impact of price fluctuations related to NGLs. In our Natural Gas Pipelines segment, we are exposed to commodity price risk because our intrastate and interstate natural gas pipelines retain natural gas from our customers for operations or as part of our fee for services provided. When the amount of natural gas consumed in operations by these pipelines differs from the amount provided by our customers, our pipelines must buy or sell natural gas, or store or use natural gas from inventory, which can expose us to commodity price risk depending on the regulatory treatment for this activity. To the extent that commodity price risk in our Natural Gas Pipelines segment is not mitigated by fuel cost-recovery mechanisms, we use physical-forward sales or purchases to reduce the impact of price fluctuations related to natural gas. At March 31, 2016 , and December 31, 2015 , there were no financial derivative instruments with respect to our natural gas pipeline operations. Interest-rate risk - We 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. As of March 31, 2016 we had interest-rate swaps with notional amounts totaling $1.0 billion to hedge the variability of our LIBOR-based interest payments. In addition, we had forward-starting interest-rate swaps with notional amounts totaling $400 million at March 31, 2016, and December 31, 2015, 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. All of our interest-rate swaps are designated as cash flow hedges. Accounting Treatment - We 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 sales - Fair value not recorded - Change in fair value not recognized in earnings Mark-to-market - Recorded at fair value - Change in fair value recognized in 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 derivative instrument is reported initially as a component of accumulated other comprehensive income (loss) - Effective portion of the gain or loss on the derivative instrument is reclassified out of accumulated other 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 recorded as an adjustment to book value - Change in fair value of the hedged item is recognized in earnings To reduce our exposure to fluctuations in natural gas, NGLs and condensate prices, we periodically enter into futures, forward purchases and 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 our 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. We also document our normal purchases and normal sales transactions that we expect to result in physical delivery and that we elect to exempt from derivative accounting treatment. The realized revenues and purchase costs of our 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. Fair Values of Derivative Instruments - The following table sets forth the fair values of derivative instruments for the periods indicated: March 31, 2016 December 31, 2015 Assets (a) (Liabilities) (a) Assets (b) (Liabilities) (b) ( Thousands of dollars ) Derivatives designated as hedging instruments Commodity contracts Financial contracts $ 53,723 $ (4,577 ) $ 39,255 $ (1,440 ) Physical contracts 1,592 (1,940 ) 3,591 — Interest-rate contracts — (41,547 ) — (9,936 ) Total derivatives designated as hedging instruments 55,315 (48,064 ) 42,846 (11,376 ) Derivatives not designated as hedging instruments Commodity contracts Financial contracts 8,145 (8,298 ) 6,919 (6,586 ) Total derivatives not designated as hedging instruments 8,145 (8,298 ) 6,919 (6,586 ) Total derivatives $ 63,460 $ (56,362 ) $ 49,765 $ (17,962 ) (a) - Included on a net basis in other current assets, other current liabilities or deferred credits and other liabilities in our Consolidated Balance Sheets. (b) - Included on a net basis in other current assets or other current liabilities in our Consolidated Balance Sheets. Notional Quantities for Derivative Instruments - The following table sets forth the notional quantities for derivative instruments held for the periods indicated: March 31, 2016 December 31, 2015 Contract Type Purchased/ Payor Sold/ Receiver Purchased/ Payor Sold/ Receiver Derivatives designated as hedging instruments: Cash flow hedges Fixed price - Natural gas ( Bcf ) Futures and swaps — (39.9 ) — (27.1 ) - Natural gas ( Bcf ) Put options 57.1 — — — - Crude oil and NGLs ( MMBbl ) Futures, forwards and swaps — (4.2 ) — (2.3 ) - Propane ( MMBbl ) Put options 1.8 — — — Basis - Natural gas ( Bcf ) Futures and swaps — (39.9 ) — (27.1 ) Interest-rate contracts ( Millions of dollars ) Forward-starting swaps $ 1,400.0 $ — $ 400.0 $ — Derivatives not designated as hedging instruments: Fixed price - NGLs ( MMBbl ) Futures, forwards and swaps 2.1 (2.0 ) 0.6 (0.6 ) 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 our actual exposure to market or credit risk. Cash Flow Hedges - At March 31, 2016 , our Consolidated Balance Sheet reflected a net loss of $149.7 million in accumulated other comprehensive loss. The portion of accumulated other comprehensive loss attributable to our commodity derivative financial instruments is an unrealized gain of $38.7 million , which will be realized within the next 21 months as the forecasted transactions affect earnings. If commodity prices remain at current levels, we will realize approximately $38.7 million in net gains over the next 12 months and an immaterial amount of net gains thereafter. The amount deferred in accumulated other comprehensive loss attributable to our settled interest-rate swaps is a loss of $137.8 million , which will be recognized over the life of the long-term, fixed-rate debt, including losses of $15.9 million that 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 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 the debt. The following table sets forth the unrealized effect of cash flow hedges recognized in other comprehensive income (loss) for the periods indicated: Three Months Ended Derivatives in Cash Flow Hedging Relationships March 31, 2016 2015 ( Thousands of dollars ) Commodity contracts $ 11,678 $ 10,019 Interest-rate contracts (31,611 ) (22,576 ) Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion) $ (19,933 ) $ (12,557 ) 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 Hedging Relationships Location of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion) Three Months Ended March 31, 2016 2015 ( Thousands of dollars ) Commodity contracts Commodity sales revenues $ 14,499 $ 14,172 Interest-rate contracts Interest expense (3,819 ) (2,839 ) Total gain (loss) reclassified from accumulated other comprehensive loss into net income on derivatives (effective portion) $ 10,680 $ 11,333 Ineffectiveness related to our cash flow hedges was not material for the three months ended March 31, 2016 and 2015 . 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, 2016 and 2015 , there were no gains or losses due to the discontinuance of cash flow hedge treatment. Credit Risk - We monitor the creditworthiness of our counterparties and compliance with policies and limits established by our Risk Oversight and Strategy Committee. We maintain credit policies with regard to our 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. We have counterparties whose credit is not rated, and for those customers, we use internally developed credit ratings. From time to time, we may enter into financial derivative instruments that contain provisions that require us to maintain an investment-grade credit rating from S&P and/or Moody’s. If our credit ratings on our 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 at March 31, 2016 . The counterparties to our derivative contracts consist primarily of major energy companies, financial institutions and commercial and industrial end users. This concentration of counterparties may affect our 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 our 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, 2016 , the net credit exposure from our derivative assets is primarily with investment-grade companies in the financial services sector.

SHORT-TERM BORROWINGS (Notes)

SHORT-TERM BORROWINGS (Notes)	3 Months Ended
	Mar. 31, 2016
Short-term Debt [Abstract]
SHORT-TERM BORROWINGS	SHORT-TERM BORROWINGS Partnership Credit Agreement - In January 2016, we extended the term of our Partnership Credit Agreement by one year to January 2020. Our Partnership Credit Agreement 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. Our Partnership Credit Agreement is available for general partnership purposes. We had $14 million of letters of credit issued, no borrowings outstanding and approximately $1.9 billion capacity available at March 31, 2016 , under our Partnership Credit Agreement. Our Partnership Credit Agreement contains provisions for an applicable margin rate and an annual facility fee, both of which adjust with changes in our credit rating. Under the terms of the Partnership Credit Agreement, based on our current credit ratings, borrowings, if any, will accrue at LIBOR plus 117.5 basis points , and the annual facility fee is 20 basis points . Our Partnership Credit Agreement is guaranteed fully and unconditionally by the Intermediate Partnership. Borrowings under our Partnership Credit Agreement are nonrecourse to ONEOK. Our Partnership 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 our Partnership 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 we consummate 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. If we were to breach certain covenants in our Partnership Credit Agreement, amounts outstanding under our Partnership Credit Agreement, if any, may become due and payable immediately. At March 31, 2016 , our ratio of indebtedness to adjusted EBITDA was 4.2 to 1, and we were in compliance with all covenants under our Partnership Credit Agreement. Neither we nor ONEOK 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. Commercial Paper Program - At March 31, 2016 , we had $445 million of commercial paper outstanding under our $2.4 billion commercial paper program with weighted-average interest rates of 1.36 percent . Amounts outstanding under our commercial paper program reduce the borrowing capacity under our Partnership Credit Agreement.

LONG TERM DEBT LONG-TERM DEBT (

LONG TERM DEBT LONG-TERM DEBT (Notes)	3 Months Ended
	Mar. 31, 2016
Debt Instrument [Line Items]
Long-term Debt [Text Block]	LONG-TERM DEBT The following table sets forth our long-term debt for the periods indicated: March 31, December 31, 2016 2015 ( Thousands of dollars ) ONEOK Partners $650,000 at 3.25% due 2016 $ — $ 650,000 $450,000 at 6.15% due 2016 450,000 450,000 $400,000 at 2.0% due 2017 400,000 400,000 $425,000 at 3.2% due 2018 425,000 425,000 $1,000,000 term loan, variable rate, due 2019 1,000,000 — $500,000 at 8.625% due 2019 500,000 500,000 $300,000 at 3.8% due 2020 300,000 300,000 $900,000 at 3.375% due 2022 900,000 900,000 $425,000 at 5.0% due 2023 425,000 425,000 $500,000 at 4.9% due 2025 500,000 500,000 $600,000 at 6.65% due 2036 600,000 600,000 $600,000 at 6.85% due 2037 600,000 600,000 $650,000 at 6.125% due 2041 650,000 650,000 $400,000 at 6.2% due 2043 400,000 400,000 Guardian Pipeline Average 7.85% due 2022 49,995 51,907 Total long-term debt 7,199,995 6,851,907 Unamortized debt issuance costs and discounts (50,107 ) (48,945 ) Current maturities (457,650 ) (107,650 ) Long-term debt, excluding current maturities $ 6,692,238 $ 6,695,312 Debt Issuances and Maturities - In January 2016, we entered into the $1.0 billion senior unsecured delayed-draw Term Loan Agreement with a syndicate of banks. The Term Loan Agreement matures in January 2019 and bears interest at LIBOR plus a margin that is based on the credit ratings assigned to the Company’s senior, unsecured, long-term indebtedness. Based on our current applicable credit rating, borrowings on the Term Loan Agreement accrue at LIBOR plus 130 basis points . At March 31, 2016, the interest rate was 1.74 percent . The Term Loan Agreement contains an option, which may be exercised up to two times, to extend the term of the loan, in each case, for an additional one-year term, subject to approval of the banks. The Term Loan Agreement allows prepayment of all or any portion outstanding without penalty or premium and contains substantially the same covenants as our Partnership Credit Agreement. During the first quarter 2016, we drew the full $1.0 billion available under the agreement and used the proceeds to repay our $650 million , 3.25 percent senior notes, to repay amounts outstanding under our commercial paper program and for general partnership purposes. At March 31, 2016 , our $450 million , 6.15 percent senior notes due October 1, 2016, are reflected in current maturities of long-term debt in our Consolidated Balance Sheet. In March 2015, we 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 other expenses, were approximately $792.3 million . We used the proceeds to repay amounts outstanding under our commercial paper program and for general partnership purposes.

EQUITY (Notes)

EQUITY (Notes)	3 Months Ended
	Mar. 31, 2016
Equity [Abstract]
EQUITY	EQUITY ONEOK - ONEOK and its affiliates owned all of the Class B units, 41.3 million common units and the entire 2 percent general partner interest in us, which together constituted a 41.2 percent ownership interest in us at March 31, 2016 . Equity Issuances - In August 2015, we completed a private placement of 21.5 million common units at a price of $30.17 per unit with ONEOK. Additionally, we completed a concurrent sale of approximately 3.3 million common units at a price of $30.17 per unit to funds managed by Kayne Anderson Capital Advisors in a registered direct offering, which were issued through our existing “at-the-market” equity program. The combined offerings generated net cash proceeds of approximately $749 million . In conjunction with these issuances, ONEOK Partners GP contributed approximately $15.3 million in order to maintain its 2 percent general partner interest in us. We used the proceeds for general partnership purposes, including capital expenditures and repayment of commercial paper borrowings. We have an “at-the-market” equity program for the offer and sale from time to time of our common units, up to an aggregate amount of $650 million . The program allows us to offer and sell our common units at prices we deem 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 us and the sales agent. We are under no obligation to offer and sell common units under the program. At March 31, 2016 , we had approximately $138 million of registered common units available for issuance through our “at-the-market” equity program. During the three months ended March 31, 2016 , no common units were sold through our “at-the-market” equity program. During the three months ended March 31, 2015 , we sold 1.7 million common units through our “at-the-market” equity program. The net proceeds, including ONEOK Partners GP’s contribution to maintain its 2 percent general partner interest in us, were approximately $71.6 million , which were used for general partnership purposes. During the year ended December 31, 2015 , we sold 10.5 million common units through our “at-the-market” equity program, including the units sold to funds managed by Kayne Anderson Capital Advisors in the offering discussed above. The net proceeds, including ONEOK Partners GP’s contribution to maintain its 2 percent general partner interest in us, were approximately $381.6 million , which were used for general partnership purposes, including repayment of commercial paper borrowings. Partnership Agreement - Available cash, as defined in our Partnership Agreement, generally will be distributed to our general partner and limited partners according to their partnership percentages of 2 percent and 98 percent, respectively. Our 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 our Partnership Agreement, our 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. Cash Distributions - In April 2016 , our general partner declared a cash distribution of $0.79 per unit ( $3.16 per unit on an annualized basis) for the first quarter 2016 , which will be paid on May 13, 2016 , to unitholders of record at the close of business on May 2, 2016 . The following table shows our distributions paid during the periods indicated: Three Months Ended March 31, 2016 2015 ( Thousands, except per unit amounts ) Distribution per unit $ 0.79 $ 0.79 General partner distributions $ 6,660 $ 5,914 Incentive distributions 100,538 89,279 Distributions to general partner 107,198 95,193 Limited partner distributions to ONEOK 90,323 73,302 Limited partner distributions to other unitholders 135,480 127,211 Total distributions paid $ 333,001 $ 295,706 Distributions are declared and paid within 45 days of the completion of each quarter. The following table shows our distributions declared for the periods indicated: Three Months Ended March 31, 2016 2015 ( Thousands, except per unit amounts ) Distribution per unit $ 0.79 $ 0.79 General partner distributions $ 6,660 $ 5,955 Incentive distributions 100,538 89,889 Distributions to general partner 107,198 95,844 Limited partner distributions to ONEOK 90,323 73,302 Limited partner distributions to other unitholders 135,480 128,583 Total distributions declared $ 333,001 $ 297,729

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ACCUMULATED OTHER COMPREHENSIVE INCOME (Notes)	3 Months Ended
	Mar. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Abstract]
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	ACCUMULATED OTHER COMPREHENSIVE LOSS The following table sets forth the balance in accumulated other comprehensive loss for the period indicated: Unrealized Gains (Losses) on Risk- Management Assets/Liabilities Unrealized Gains (Losses) on Risk- Management Assets/Liabilities of Unconsolidated Affiliates Accumulated Other Comprehensive Loss ( Thousands of dollars ) January 1, 2016 $ (111,357 ) $ (1,925 ) $ (113,282 ) Other comprehensive income (loss) before reclassifications (19,933 ) (5,801 ) (25,734 ) Amounts reclassified from accumulated other comprehensive loss (10,680 ) — (10,680 ) Net current-period other comprehensive income (loss) attributable to ONEOK Partners (30,613 ) (5,801 ) (36,414 ) March 31, 2016 $ (141,970 ) $ (7,726 ) $ (149,696 ) The following table sets forth the effect of reclassifications from accumulated other comprehensive loss in our Consolidated Statements of Income for the periods indicated: Details about Accumulated Other Components Three Months Ended Affected Line Item in the Income March 31, 2016 2015 ( Thousands of dollars ) Unrealized gains (losses) on risk-management assets/liabilities Commodity contracts $ 14,499 $ 14,172 Commodity sales revenues Interest-rate contracts (3,819 ) (2,839 ) Interest expense Total reclassifications for the period attributable to ONEOK Partners $ 10,680 $ 11,333 Net income attributable to ONEOK Partners

LIMITED PARTNERS' NET INCOME PE

LIMITED PARTNERS' NET INCOME PER UNIT	3 Months Ended
	Mar. 31, 2016
Limited Partners' Net Income Per Unit and Distributions to Partners [Abstract]
LIMITED PARTNERS' NET INCOME PER UNIT	LIMITED PARTNERS’ NET INCOME PER UNIT Limited partners’ net income per unit is computed by dividing net income attributable to ONEOK Partners, L.P., after deducting the general partner’s allocation as discussed below, by the weighted-average number of outstanding limited partner units, which includes our common and Class B limited partner units. Because ONEOK has conditionally waived its right to increased quarterly distributions, until it gives 90 days notice of the withdrawal of the waiver, currently each Class B and common unit share equally in the earnings of the Partnership, and neither has any liquidation or other preferences. ONEOK Partners GP owns the entire 2 percent general partnership interest in us, which entitles it to incentive distribution rights that provide for an increasing proportion of cash distributions from the Partnership as the distributions made to limited partners increase above specified levels. For purposes of our calculation of limited partners’ net income per unit, net income attributable to ONEOK Partners, L.P. is allocated to the general partner as follows: (i) an amount based upon the 2 percent general partner interest in net income attributable to ONEOK Partners, L.P.; and (ii) the amount of the general partner’s incentive distribution rights based on the total cash distributions declared for the period. The terms of our Partnership Agreement limit the general partner’s incentive distribution to the amount of available cash calculated for the period. As such, incentive distribution rights are not allocated on undistributed earnings. For additional information regarding our general partner’s incentive distribution rights, see “Partnership Agreement” in Note F .

UNCONSOLIDATED AFFILIATES

UNCONSOLIDATED AFFILIATES	3 Months Ended
	Mar. 31, 2016
Equity Method Investments and Joint Ventures [Abstract]
UNCONSOLIDATED AFFILIATES	UNCONSOLIDATED AFFILIATES Equity in Net Earnings from Investments - The following table sets forth our equity in net earnings from investments for the periods indicated: Three Months Ended March 31, 2016 2015 ( Thousands of dollars ) Northern Border Pipeline $ 18,674 $ 19,702 Overland Pass Pipeline Company 13,304 6,887 Other 936 4,332 Equity in net earnings from investments $ 32,914 $ 30,921 Unconsolidated Affiliates Financial Information - The following table sets forth summarized combined financial information of our unconsolidated affiliates for the periods indicated: Three Months Ended March 31, 2016 2015 ( Thousands of dollars ) Income Statement Operating revenues $ 136,572 $ 129,581 Operating expenses $ 58,699 $ 57,579 Net income $ 72,037 $ 66,359 Distributions paid to us $ 46,553 $ 39,429 We incurred expenses in transactions with unconsolidated affiliates of $33.6 million and $19.9 million for the three months ended March 31, 2016 and 2015 , respectively, primarily related to Overland Pass Pipeline Company and Northern Border Pipeline. Accounts payable to our equity-method investees at March 31, 2016 , and December 31, 2015 , were $11.8 million and $8.0 million , respectively. Northern Border Pipeline - The Northern Border Pipeline partnership agreement provides that distributions to Northern Border Pipeline’s partners are to be made on a pro rata basis according to each partner’s percentage interest. The Northern Border Pipeline Management Committee determines the amount and timing of such distributions. Any changes to, or suspension of, the cash distribution policy of Northern Border Pipeline requires the unanimous approval of the Northern Border Pipeline Management Committee. Cash distributions are equal to 100 percent of distributable cash flow as determined from Northern Border Pipeline’s financial statements based upon EBITDA, less interest expense and maintenance capital expenditures. Loans or other advances from Northern Border Pipeline to its partners or affiliates are prohibited under its credit agreement. Overland Pass Pipeline Company - The Overland Pass Pipeline Company limited liability company agreement provides that distributions to Overland Pass Pipeline Company’s members are to be made on a pro rata basis according to each member’s percentage interest. The Overland Pass Pipeline Company Management Committee determines the amount and timing of such distributions. Any changes to, or suspension of, the cash distributions from Overland Pass Pipeline Company requires the unanimous approval of the Overland Pass Pipeline Management Committee. Cash distributions are equal to 100 percent of available cash as defined in the limited liability company agreement. Roadrunner Gas Transmission - In March 2015, we entered into a 50-50 joint venture with a subsidiary of Fermaca Infrastructure B.V. (Fermaca), a Mexico City-based natural gas infrastructure company, to construct a pipeline to transport natural gas from the Permian Basin in West Texas to the Mexican border near El Paso, Texas. During the three months ended March 31, 2016 , we made no contributions to Roadrunner, and we expect to contribute approximately $50 million to Roadrunner during the remainder of 2016. The Roadrunner limited liability company agreement provides that distributions to members are made on a pro rata basis according to each member’s ownership interest. The Roadrunner Management Committee determines the amount and timing of such distributions. Any changes to, or suspension of, the cash distributions from Roadrunner requires approval of the Roadrunner Management Committee. Voting rights for the Roadrunner Management Committee are allocated on a pro rata basis according to each member’s ownership interest. Cash distributions are equal to 100 percent of available cash, as defined in the limited liability company agreement.

RELATED-PARTY TRANSACTIONS

RELATED-PARTY TRANSACTIONS	3 Months Ended
	Mar. 31, 2016
Related Party Transactions [Abstract]
RELATED-PARTY TRANSACTIONS	RELATED-PARTY TRANSACTIONS Under the Services Agreement with ONEOK and ONEOK Partners GP (the Services Agreement), our operations and the operations of ONEOK and its affiliates can combine or share certain common services in order to operate more efficiently and cost effectively. Under the Services Agreement, ONEOK provides to us similar services that it provides to its affiliates, including those services required to be provided pursuant to our Partnership Agreement. ONEOK Partners GP may purchase services from ONEOK and its affiliates pursuant to the terms of the Services Agreement. ONEOK Partners GP has no employees and utilizes the services of ONEOK to fulfill its operating obligations. ONEOK and its affiliates provide a variety of services to us under the Services Agreement, including cash management and financial services, employee benefits provided through ONEOK’s benefit plans, legal and administrative services, insurance and office space leased in ONEOK’s headquarters building and other field locations. Where costs are incurred specifically on behalf of one of our affiliates, the costs are billed directly to us by ONEOK. In other situations, the costs may be allocated to us through a variety of methods, depending upon the nature of the expense and activities. For the three months ended March 31, 2016 and 2015 , $87.7 million and $89.5 million , respectively, of our operating expenses were incurred with ONEOK and its affiliates. ONEOK Partners GP made additional general partner contributions to us of approximately $1.1 million during the three months ended March 31, 2015. See Note F for additional information about cash distributions paid to ONEOK for its general partner and limited partner interests.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	3 Months Ended
	Mar. 31, 2016
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Environmental Matters and Pipeline Safety - The operation of pipelines, plants and other facilities for the gathering, processing, transportation and storage of natural gas, NGLs, condensate and other products is subject to numerous and complex laws and regulations pertaining to health, safety and the environment. As an owner and/or operator of these facilities, we must comply with United States laws and regulations at the federal, state and local levels that relate to air and water quality, hazardous and solid waste management and disposal, and other environmental matters. The cost of planning, designing, constructing and operating pipelines, plants and other facilities must incorporate compliance with environmental laws and regulations and safety standards. Failure to comply with these laws and regulations may trigger a variety of administrative, civil and potentially criminal enforcement measures, including citizen suits, which can include the assessment of monetary penalties, the imposition of remedial requirements and the issuance of injunctions or restrictions on operation. Management believes that, based on currently known information, compliance with these laws and regulations will not have a material adverse effect on our results of operations, financial condition or cash flows. Legal Proceedings - We are a party to various litigation matters and claims that have arisen in the normal course of our operations. While the results of these 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, 2016
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
SEGMENTS	SEGMENTS Segment Descriptions - Our operations are divided into three reportable business segments, as follows: • our Natural Gas Gathering and Processing segment gathers, treats and processes natural gas; • our Natural Gas Liquids segment gathers, treats, fractionates and transports NGLs and stores, markets and distributes NGL products; and • our Natural Gas Pipelines segment operates regulated interstate and intrastate natural gas transmission pipelines and natural gas storage facilities. Accounting Policies - The accounting policies of the segments are described in Note A of the Notes to Consolidated Financial Statements in our Annual Report. Beginning in 2016, we present financial results using adjusted EBITDA by segment, a non-GAAP financial measure. We believe this non-GAAP financial measure is useful to investors because it is used by many companies in our industry as a measurement of financial performance and is commonly employed by financial analysts and others to evaluate our financial performance and to compare our financial performance with the performance of other publicly traded partnerships within our industry. Adjusted EBITDA is defined as net income adjusted for interest expense, depreciation and amortization, noncash impairment charges, income taxes and AFUDC and other noncash items. Adjusted EBITDA should not be considered an alternative to net income, earnings per unit or any other measure of financial performance presented in accordance with GAAP. Additionally, this calculation may not be comparable with similarly titled measures of other companies. Prior period segment disclosures have been recast to reflect this change. Customers - The primary customers for our Natural Gas Gathering and Processing segment are crude oil and natural gas producers, which include both large integrated and independent exploration and production companies. Our Natural Gas Liquids segment’s customers are primarily NGL and natural gas gathering and processing companies; large integrated and independent crude oil and natural gas production companies; propane distributors; ethanol producers; and petrochemical, refining and NGL marketing companies. Our Natural Gas Pipelines segment’s customers are primarily local natural gas distribution companies, electric-generation companies, large industrial companies, municipalities, irrigation customers and marketing companies. For the three months ended March 31, 2016 and March 31, 2015 , we had one customer, BP p.l.c. or its affiliates, from which we received $221.2 million and $184.9 million , respectively, in total revenues from all of our operating segments, or approximately 12 percent and 10 percent of our consolidated revenues, respectively. Operating Segment Information - The following tables set forth certain selected financial information for our operating segments for the periods indicated: Three Months Ended March 31, 2016 Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Other and Eliminations Total ( Thousands of dollars ) Sales to unaffiliated customers $ 317,046 $ 1,371,425 $ 85,474 $ — $ 1,773,945 Intersegment revenues 114,965 115,965 499 (231,429 ) — Total revenues 432,011 1,487,390 85,973 (231,429 ) 1,773,945 Cost of sales and fuel (exclusive of items shown separately below) 266,300 1,156,950 3,932 (231,444 ) 1,195,738 Operating costs 69,606 73,182 27,513 79 170,380 Depreciation and amortization 41,851 40,706 11,179 — 93,736 (Gain) loss on sale of assets (1,245 ) 64 (2,964 ) — (4,145 ) Operating income $ 55,499 $ 216,488 $ 46,313 $ (64 ) $ 318,236 Equity in net earnings from investments $ 2,815 $ 13,347 $ 16,752 $ — $ 32,914 Investments in unconsolidated affiliates $ 73,769 $ 474,482 $ 380,958 $ — $ 929,209 Total assets $ 5,196,190 $ 8,016,245 $ 1,847,352 $ (115,065 ) $ 14,944,722 Noncontrolling interests in consolidated subsidiaries $ — $ 160,354 $ — $ — $ 160,354 Capital expenditures $ 141,497 $ 34,207 $ 17,948 $ 2,244 $ 195,896 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $281.8 million , of which $230.8 million related to sales within the segment, cost of sales and fuel of $106.8 million and operating income of $115.6 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $54.8 million , cost of sales and fuel of $5.6 million and operating income of $23.1 million . Three Months Ended March 31, 2015 Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Other and Eliminations Total ( Thousands of dollars ) Sales to unaffiliated customers $ 288,016 $ 1,434,813 $ 81,930 $ — $ 1,804,759 Intersegment revenues 167,607 61,279 1,619 (230,505 ) — Total revenues $ 455,623 $ 1,496,092 $ 83,549 $ (230,505 ) $ 1,804,759 Cost of sales and fuel (exclusive of items shown separately below) 330,931 1,228,865 14,426 (230,358 ) 1,343,864 Operating costs 69,209 82,246 27,242 (538 ) 178,159 Depreciation and amortization 35,797 39,294 10,756 — 85,847 (Gain) loss on sale of assets (1 ) 8 (1 ) — 6 Operating income $ 19,687 $ 145,679 $ 31,126 $ 391 $ 196,883 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 $ 4,887,938 $ 8,106,766 $ 1,815,235 $ (2,424 ) $ 14,807,515 Noncontrolling interests in consolidated subsidiaries $ 4,156 $ 162,958 $ — $ 15 $ 167,129 Capital expenditures $ 255,301 $ 73,466 $ 9,592 $ 4,677 $ 343,036 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $209.8 million , of which $165.3 million related to sales within the segment, cost of sales and fuel of $85.7 million and operating income of $64.9 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $54.2 million , cost of sales and fuel of $7.2 million and operating income of $21.7 million . Three Months Ended March 31, ( Unaudited ) 2016 2015 ( Thousands of dollars ) Segment Adjusted EBITDA: Natural Gas Gathering and Processing $ 100,035 $ 60,518 Natural Gas Liquids 270,169 192,655 Natural Gas Pipelines 74,339 70,712 Other 43 413 Depreciation and amortization (93,736 ) (85,847 ) Interest expense, net of capitalized interest (92,555 ) (80,709 ) Income taxes (2,028 ) (2,760 ) AFUDC and other 19 (7,950 ) Net income $ 256,286 $ 147,032

SUPPLEMENTAL CONDENSED CONSOLID

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION	3 Months Ended
	Mar. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Supplemental Condensed Consolidating Financial Information	SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION We have no significant assets or operations other than our investment in our wholly owned subsidiary, the Intermediate Partnership. The Intermediate Partnership holds all our partnership interests and equity in our subsidiaries, as well as a 50 percent interest in Northern Border Pipeline. The Intermediate Partnership guarantees our senior notes and borrowings, if any, under the Partnership Credit Agreement. The Intermediate Partnership’s guarantees of our senior notes and of any borrowings under the Partnership Credit Agreement are full and unconditional, subject to certain customary automatic release provisions. For purposes of the following footnote: • we are referred to as “Parent”; • the Intermediate Partnership is referred to as “Guarantor Subsidiary”; and • the “Non-Guarantor Subsidiaries” are all subsidiaries other than the Guarantor Subsidiary. The following unaudited supplemental condensed consolidating financial information is presented on an equity-method basis reflecting the Parent’s separate accounts, the Guarantor Subsidiary’s separate accounts, the combined accounts of the Non-Guarantor Subsidiaries, the combined consolidating adjustments and eliminations, and the Parent’s consolidated amounts for the periods indicated. Condensed Consolidating Statements of Income Three Months Ended March 31, 2016 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ 1,283.5 $ — $ 1,283.5 Services — — 490.4 — 490.4 Total revenues — — 1,773.9 — 1,773.9 Cost of sales and fuel (exclusive of items shown separately below) — — 1,195.7 — 1,195.7 Operating expenses — — 264.1 — 264.1 (Gain) loss on sale of assets — — (4.1 ) — (4.1 ) Operating income — — 318.2 — 318.2 Equity in net earnings from investments 253.5 253.5 14.2 (488.3 ) 32.9 Other income (expense), net 94.4 94.4 (0.2 ) (188.8 ) (0.2 ) Interest expense, net (94.4 ) (94.4 ) (92.6 ) 188.8 (92.6 ) Income before income taxes 253.5 253.5 239.6 (488.3 ) 258.3 Income taxes — — (2.0 ) — (2.0 ) Net income 253.5 253.5 237.6 (488.3 ) 256.3 Less: Net income attributable to noncontrolling interests — — 2.8 — 2.8 Net income attributable to ONEOK Partners, L.P. $ 253.5 $ 253.5 $ 234.8 $ (488.3 ) $ 253.5 Three Months Ended March 31, 2015 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ 1,435.7 $ — $ 1,435.7 Services — — 369.1 — 369.1 Total revenues — — 1,804.8 — 1,804.8 Cost of sales and fuel (exclusive of items shown separately below) — — 1,343.9 — 1,343.9 Operating expenses — — 264.0 — 264.0 (Gain) loss on sale of assets — — — — — Operating income — — 196.9 — 196.9 Equity in net earnings from investments 145.6 145.6 11.3 (271.6 ) 30.9 Other income (expense), net 86.8 86.8 2.7 (173.6 ) 2.7 Interest expense, net (86.8 ) (86.8 ) (80.7 ) 173.6 (80.7 ) Income before income taxes 145.6 145.6 130.2 (271.6 ) 149.8 Income taxes — — (2.8 ) — (2.8 ) Net income 145.6 145.6 127.4 (271.6 ) 147.0 Less: Net income attributable to noncontrolling interests — — 1.4 — 1.4 Net income attributable to ONEOK Partners, L.P. $ 145.6 $ 145.6 $ 126.0 $ (271.6 ) $ 145.6 Condensed Consolidating Statements of Comprehensive Income Three Months Ended March 31, 2016 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 253.5 $ 253.5 $ 237.6 $ (488.3 ) $ 256.3 Other comprehensive income (loss) Unrealized gains (losses) on derivatives (19.9 ) 11.7 11.7 (23.4 ) (19.9 ) Realized (gains) losses on derivatives recognized in net income (10.7 ) (14.5 ) (14.5 ) 29.0 (10.7 ) Other comprehensive income (loss) on investments in unconsolidated affiliates (5.8 ) (5.8 ) (5.8 ) 11.6 (5.8 ) Total other comprehensive income (loss) (36.4 ) (8.6 ) (8.6 ) 17.2 (36.4 ) Comprehensive income 217.1 244.9 229.0 (471.1 ) 219.9 Less: Comprehensive income attributable to noncontrolling interests — — 2.8 — 2.8 Comprehensive income attributable to ONEOK Partners, L.P. $ 217.1 $ 244.9 $ 226.2 $ (471.1 ) $ 217.1 Three Months Ended March 31, 2015 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 145.6 $ 145.6 $ 127.4 $ (271.6 ) $ 147.0 Other comprehensive income (loss) Unrealized gains (losses) on derivatives (12.6 ) 10.0 10.0 (20.0 ) (12.6 ) Realized (gains) losses on derivatives recognized in net income (11.3 ) (14.2 ) (14.2 ) 28.4 (11.3 ) Total other comprehensive income (loss) (23.9 ) (4.2 ) (4.2 ) 8.4 (23.9 ) Comprehensive income 121.7 141.4 123.2 (263.2 ) 123.1 Less: Comprehensive income attributable to noncontrolling interests — — 1.4 — 1.4 Comprehensive income attributable to ONEOK Partners, L.P. $ 121.7 $ 141.4 $ 121.8 $ (263.2 ) $ 121.7 Condensed Consolidating Balance Sheets March 31, 2016 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total Assets ( Millions of dollars ) Current assets Cash and cash equivalents $ — $ 9.9 $ — $ — $ 9.9 Accounts receivable, net — — 520.8 — 520.8 Affiliate receivables — — 3.6 — 3.6 Natural gas and natural gas liquids in storage — — 156.1 — 156.1 Other current assets 0.4 — 165.7 — 166.1 Total current assets 0.4 9.9 846.2 — 856.5 Property, plant and equipment Property, plant and equipment — — 14,448.9 — 14,448.9 Accumulated depreciation and amortization — — 2,126.4 — 2,126.4 Net property, plant and equipment — — 12,322.5 — 12,322.5 Investments and other assets Intercompany notes receivable 10,383.8 7,704.4 — (18,088.2 ) — Other assets 3,505.9 6,175.4 1,406.4 (9,322.0 ) 1,765.7 Total investments and other assets 13,889.7 13,879.8 1,406.4 (27,410.2 ) 1,765.7 Total assets $ 13,890.1 $ 13,889.7 $ 14,575.1 $ (27,410.2 ) $ 14,944.7 Liabilities and equity Current liabilities Current maturities of long-term debt $ 450.0 $ — $ 7.7 $ — $ 457.7 Short-term borrowings 444.6 — — — 444.6 Accounts payable — — 513.5 — 513.5 Affiliate payables — — 20.1 — 20.1 Other current liabilities 121.7 — 151.7 — 273.4 Total current liabilities 1,016.3 — 693.0 — 1,709.3 Intercompany debt — 10,383.8 7,704.4 (18,088.2 ) — Long-term debt, excluding current maturities 6,649.9 — 42.3 — 6,692.2 Deferred credits and other liabilities 6.6 — 158.9 — 165.5 Commitments and contingencies Equity Equity excluding noncontrolling interests in consolidated subsidiaries 6,217.3 3,505.9 5,816.1 (9,322.0 ) 6,217.3 Noncontrolling interests in consolidated subsidiaries — — 160.4 — 160.4 Total equity 6,217.3 3,505.9 5,976.5 (9,322.0 ) 6,377.7 Total liabilities and equity $ 13,890.1 $ 13,889.7 $ 14,575.1 $ (27,410.2 ) $ 14,944.7 December 31, 2015 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total Assets ( Millions of dollars ) Current assets Cash and cash equivalents $ — $ 5.1 $ — $ — $ 5.1 Accounts receivable, net — — 593.4 — 593.4 Affiliate receivables — — 8.0 — 8.0 Natural gas and natural gas liquids in storage — — 128.1 — 128.1 Other current assets 4.1 — 144.5 — 148.6 Total current assets 4.1 5.1 874.0 — 883.2 Property, plant and equipment Property, plant and equipment — — 14,307.5 — 14,307.5 Accumulated depreciation and amortization — — 2,050.7 — 2,050.7 Net property, plant and equipment — — 12,256.8 — 12,256.8 Investments and other assets Intercompany notes receivable 10,144.9 7,781.8 — (17,926.7 ) — Other assets 3,594.0 5,952.0 1,425.2 (9,183.6 ) 1,787.6 Total investments and other assets 13,738.9 13,733.8 1,425.2 (27,110.3 ) 1,787.6 Total assets $ 13,743.0 $ 13,738.9 $ 14,556.0 $ (27,110.3 ) $ 14,927.6 Liabilities and equity Current liabilities Current maturities of long-term debt $ 100.0 $ — $ 7.7 $ — $ 107.7 Short-term borrowings 546.3 — — — 546.3 Accounts payable — — 605.4 — 605.4 Affiliate payables — — 27.1 — 27.1 Other current liabilities 112.5 — 181.4 — 293.9 Total current liabilities 758.8 — 821.6 — 1,580.4 Intercompany debt — 10,144.9 7,781.8 (17,926.7 ) — Long-term debt, excluding current maturities 6,651.0 — 44.3 — 6,695.3 Deferred credits and other liabilities — — 154.6 — 154.6 Commitments and contingencies Equity Equity excluding noncontrolling interests in consolidated subsidiaries 6,333.2 3,594.0 5,589.6 (9,183.6 ) 6,333.2 Noncontrolling interests in consolidated subsidiaries — — 164.1 — 164.1 Total equity 6,333.2 3,594.0 5,753.7 (9,183.6 ) 6,497.3 Total liabilities and equity $ 13,743.0 $ 13,738.9 $ 14,556.0 $ (27,110.3 ) $ 14,927.6 Condensed Consolidating Statements of Cash Flows Three Months Ended March 31, 2016 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 318.8 $ 18.7 $ 261.8 $ (333.0 ) $ 266.3 Investing activities Capital expenditures — — (195.9 ) — (195.9 ) Other investing activities — 3.2 23.2 — 26.4 Cash provided by (used in) investing activities — 3.2 (172.7 ) — (169.5 ) Financing activities Cash distributions: General and limited partners (333.0 ) (333.0 ) — 333.0 (333.0 ) Noncontrolling interests — — (2.5 ) — (2.5 ) Intercompany borrowings (advances), net (231.2 ) 315.9 (84.7 ) — — Borrowing (repayment) of short-term borrowings, net (101.8 ) — — — (101.8 ) Issuance of long-term debt, net of discounts 1,000.0 — — — 1,000.0 Debt financing costs (2.8 ) — — — (2.8 ) Repayment of long-term debt (650.0 ) — (1.9 ) — (651.9 ) Cash provided by (used in) financing activities (318.8 ) (17.1 ) (89.1 ) 333.0 (92.0 ) Change in cash and cash equivalents — 4.8 — — 4.8 Cash and cash equivalents at beginning of period — 5.1 — — 5.1 Cash and cash equivalents at end of period $ — $ 9.9 $ — $ — $ 9.9 Three Months Ended March 31, 2015 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 218.8 $ 19.7 $ 122.3 $ (295.7 ) $ 65.1 Investing activities Capital expenditures — — (343.0 ) — (343.0 ) Other investing activities — 1.7 8.3 — 10.0 Cash provided by (used in) investing activities — 1.7 (334.7 ) — (333.0 ) Financing activities Cash distributions: General and limited partners (295.7 ) (295.7 ) — 295.7 (295.7 ) Noncontrolling interests — — (2.2 ) — (2.2 ) Intercompany borrowings (advances), net (538.8 ) 322.3 216.5 — — Borrowing (repayment) of short-term borrowings, net (229.8 ) — — — (229.8 ) Issuance of long-term debt, net of discounts 798.9 — — — 798.9 Debt financing costs (7.9 ) — — — (7.9 ) Repayment of long-term debt — — (1.9 ) — (1.9 ) Issuance of common units, net of issuance costs 53.4 — — — 53.4 Contribution from general partner 1.1 — — — 1.1 Cash provided by (used in) financing activities (218.8 ) 26.6 212.4 295.7 315.9 Change in cash and cash equivalents — 48.0 — — 48.0 Cash and cash equivalents at beginning of period — 42.5 — — 42.5 Cash and cash equivalents at end of period $ — $ 90.5 $ — $ — $ 90.5

SUMMARY OF SIGNIFICANT ACCOUN22

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	3 Months Ended
	Mar. 31, 2016
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Basis of Accounting, Policy [Policy Text Block]	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 2015 year-end consolidated balance sheet data was derived from our audited financial statements but does not include all disclosures required by GAAP. Certain reclassifications have been made in the prior-year financial statements to conform to the current-year presentation. 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.
Accounting Standards Update 2015-16 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	In September 2015, the FASB issued ASU 2015-16, “Business Combinations (Topic 805) - Simplifying the Accounting for Measurement-Period Adjustments,” which requires that an acquirer recognize adjustments to provisional amounts that are identified during the measurement period in the reporting period in which the adjustment amounts are determined. The amendment also requires the acquirer to record the income statement effects of changes to provisional amounts in the financial statements in the period in which the adjustments occurred. This guidance was effective for public companies for fiscal years beginning after December 15, 2015. We adopted this guidance in the first quarter 2016, and there was no impact, but it could impact us in the future if we complete any acquisitions with subsequent measurement period adjustments.
Accounting Standards Update 2015-05 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	In April 2015, the FASB issued ASU 2015-05, “Intangibles—Goodwill and Other—Internal-Use Software (Subtopic 350-40): Customer’s Accounting for Fees Paid in a Cloud Computing Arrangement,” which clarifies whether a cloud computing arrangement includes a software license. If it does, the customer should account for the software license element of the arrangement consistent with the acquisition of other software licenses; if not, the customer should account for the arrangement as a service contract. This guidance was effective for public companies for fiscal years beginning after December 15, 2015. We adopted this guidance in the first quarter 2016. The impact of adopting this guidance was not material.
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 was effective for public companies for fiscal years beginning after December 15, 2015. We adopted this guidance in the first quarter 2016. The impact of adopting this guidance was not material.
Accounting Standards Update 2016-06 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	In March 2016, the FASB issued ASU 2016-06, “Derivatives and Hedging (Topic 815): Contingent Put and Call Options in Debt Instruments,” which clarifies the requirements for assessing whether a contingent call (put) option that can accelerate the payment of principal on a debt instrument is clearly and closely related to its debt host. Under the amendments in the update, assessments must be performed in accordance with the four-step decision sequence to conclude which call (put) options should be bifurcated and accounted for separately as derivatives. This guidance is effective for public companies for fiscal years beginning after December 15, 2016, and interim periods within those fiscal years, with early adoption permitted. We expect to adopt this guidance in the first quarter 2017, and we are evaluating the impact on us.
Accounting Standards Update 2016-05 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	In March 2016, the FASB issued ASU 2016-05, “Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships,” which clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. This guidance is effective for public companies for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. Early adoption is permitted. We expect to adopt this guidance in the first quarter 2017, and we are evaluating the impact on us.
Accounting Standards Update 2016-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	In February 2016, the FASB issued ASU 2016-02, “Leases (Topic 842),” which requires the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases under previous GAAP. It also requires qualitative disclosures along with specific quantitative disclosures by lessees and lessors to meet the objective of enabling users of financial statements to assess the amount, timing and uncertainty of cash flows arising from leases. This guidance is effective for public companies for fiscal years beginning after December 15, 2018, including interim periods within those fiscal years. Early adoption is permitted. We expect to adopt this guidance in the first quarter 2019, and we are evaluating the impact on us.
Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	In January 2016, the FASB issued ASU 2016-01, “Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities,” which requires all equity investments other than those accounted for using the equity method of accounting or those that result in consolidation of the investee to be measured at fair value with changes in fair value recognized in net income, eliminates the available-for-sale classification for equity securities with readily determinable fair values and eliminates the cost method for equity investments without readily determinable fair values. Additionally, this guidance eliminates the requirement to disclose the methods and significant assumptions used to estimate the fair value of financial instruments carried at amortized cost and requires the use of the exit price when measuring the fair value of such instruments for disclosure purposes. This guidance will be effective for public companies in fiscal years beginning after December 15, 2017, including interim periods within those fiscal years. Early adoption is only permitted for certain portions of the ASU. We expect to adopt this guidance in the first quarter 2018, and we are evaluating the impact on us.
Accounting Standards Update 2015-11 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements, Policy [Policy Text Block]	In July 2015, the FASB issued ASU 2015-11, “Inventory (Topic 330): Simplifying the Measurement of Inventory,” which requires that inventory, excluding inventory measured using last-in, first-out (LIFO) or the retail inventory method, be measured at the lower of cost or net realizable value. This guidance will be effective for public companies for fiscal years beginning after December 15, 2016, including interim periods within those fiscal years. We expect to adopt this guidance in the first quarter 2017, 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, “Presentation of Financial Statements - Going Concern (Subtopic 205-40): Disclosure of Uncertainties about an Entity’s Ability to Continue as a 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 expect to adopt this guidance beginning in the fourth 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 (Topic 606),” 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. In August 2015, the FASB issued ASU 2015-14, “Revenue from Contracts with Customers (Topic 606): Deferral of the Effective Date,” that deferred the effective date of ASU 2014-09 by one year. This update is now effective for interim and annual periods that begin after December 15, 2017, with either retrospective application for all periods presented or retrospective application with a cumulative effect adjustment. The FASB has issued additional ASUs, which provide further guidance and clarification on implementation issues. We expect to adopt this guidance beginning in the first quarter 2018, and we are evaluating the impact on us.

FAIR VALUE MEASUREMENTS FAIR VA

FAIR VALUE MEASUREMENTS FAIR VALUE MEASUREMENTS (Policies)	3 Months Ended
	Mar. 31, 2016
Fair Value Accounting Policy [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 our 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, data obtained from third-party pricing services and LIBOR and other liquid money-market instrument rates. 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 derivative portfolio 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 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-rate 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 natural gas basis and NGL price curves that incorporate observable and unobservable market data from broker quotes, third-party pricing services, 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 has not been 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 A24

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES (Policies)	3 Months Ended
	Mar. 31, 2016
RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES [Abstract]
Accounting treatment for derivative instruments	We 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 sales - Fair value not recorded - Change in fair value not recognized in earnings Mark-to-market - Recorded at fair value - Change in fair value recognized in 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 derivative instrument is reported initially as a component of accumulated other comprehensive income (loss) - Effective portion of the gain or loss on the derivative instrument is reclassified out of accumulated other 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 recorded as an adjustment to book value - Change in fair value of the hedged item is recognized in earnings To reduce our exposure to fluctuations in natural gas, NGLs and condensate prices, we periodically enter into futures, forward purchases and 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 our 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. We also document our normal purchases and normal sales transactions that we expect to result in physical delivery and that we elect to exempt from derivative accounting treatment. The realized revenues and purchase costs of our 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.

EQUITY (Policies)

EQUITY (Policies)	3 Months Ended
	Mar. 31, 2016
EQUITY (Policies)
Partnership agreement	Partnership Agreement - Available cash, as defined in our Partnership Agreement, generally will be distributed to our general partner and limited partners according to their partnership percentages of 2 percent and 98 percent, respectively. Our 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 our Partnership Agreement, our 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.

LIMITED PARTNERS' NET INCOME 26

LIMITED PARTNERS' NET INCOME PER UNIT LIMITED PARTNERS' NET INCOME PER UNIT(Policies)	3 Months Ended
	Mar. 31, 2016
Earnings Per Share [Abstract]
Earnings Per Share, Policy [Policy Text Block]	Limited partners’ net income per unit is computed by dividing net income attributable to ONEOK Partners, L.P., after deducting the general partner’s allocation as discussed below, by the weighted-average number of outstanding limited partner units, which includes our common and Class B limited partner units. Because ONEOK has conditionally waived its right to increased quarterly distributions, until it gives 90 days notice of the withdrawal of the waiver, currently each Class B and common unit share equally in the earnings of the Partnership, and neither has any liquidation or other preferences. ONEOK Partners GP owns the entire 2 percent general partnership interest in us, which entitles it to incentive distribution rights that provide for an increasing proportion of cash distributions from the Partnership as the distributions made to limited partners increase above specified levels. For purposes of our calculation of limited partners’ net income per unit, net income attributable to ONEOK Partners, L.P. is allocated to the general partner as follows: (i) an amount based upon the 2 percent general partner interest in net income attributable to ONEOK Partners, L.P.; and (ii) the amount of the general partner’s incentive distribution rights based on the total cash distributions declared for the period. The terms of our Partnership Agreement limit the general partner’s incentive distribution to the amount of available cash calculated for the period. As such, incentive distribution rights are not allocated on undistributed earnings. For additional information regarding our general partner’s incentive distribution rights, see “Partnership Agreement” in Note F .

RELATED-PARTY TRANSACTIONS RELA

RELATED-PARTY TRANSACTIONS RELATED-PARTY TRANSACTIONS (Policies)	3 Months Ended
	Mar. 31, 2016
Related Party Transactions [Abstract]
Allocation of Costs Incurred by Related Party, Policy [Policy Text Block]	ONEOK and its affiliates provide a variety of services to us under the Services Agreement, including cash management and financial services, employee benefits provided through ONEOK’s benefit plans, legal and administrative services, insurance and office space leased in ONEOK’s headquarters building and other field locations. Where costs are incurred specifically on behalf of one of our affiliates, the costs are billed directly to us by ONEOK. In other situations, the costs may be allocated to us through a variety of methods, depending upon the nature of the expense and activities.

SEGMENTS SEGMENTS (Policies)

SEGMENTS SEGMENTS (Policies)	3 Months Ended
	Mar. 31, 2016
Segment Accounting Policies [Abstract]
Segment Reporting, Policy [Policy Text Block]	Accounting Policies - The accounting policies of the segments are described in Note A of the Notes to Consolidated Financial Statements in our Annual Report. Beginning in 2016, we present financial results using adjusted EBITDA by segment, a non-GAAP financial measure. We believe this non-GAAP financial measure is useful to investors because it is used by many companies in our industry as a measurement of financial performance and is commonly employed by financial analysts and others to evaluate our financial performance and to compare our financial performance with the performance of other publicly traded partnerships within our industry. Adjusted EBITDA is defined as net income adjusted for interest expense, depreciation and amortization, noncash impairment charges, income taxes and AFUDC and other noncash items. Adjusted EBITDA should not be considered an alternative to net income, earnings per unit or any other measure of financial performance presented in accordance with GAAP. Additionally, this calculation may not be comparable with similarly titled measures of other companies. Prior period segment disclosures have been recast to reflect this change.

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	3 Months Ended
	Mar. 31, 2016
Fair Value Disclosures [Abstract]
Recurring Fair Value Measurements	The following tables set forth our recurring fair value measurements for the periods indicated: March 31, 2016 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net (b) ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 55,062 $ — $ 6,806 $ 61,868 $ (34,261 ) $ 27,607 Physical contracts — — 1,592 1,592 — 1,592 Total derivative assets $ 55,062 $ — $ 8,398 $ 63,460 $ (34,261 ) $ 29,199 Derivative liabilities Commodity contracts Financial contracts $ (6,451 ) $ — $ (6,424 ) $ (12,875 ) $ 12,855 $ (20 ) Physical contracts — — (1,940 ) (1,940 ) — (1,940 ) Interest-rate contracts — (41,547 ) — (41,547 ) — (41,547 ) Total derivative liabilities $ (6,451 ) $ (41,547 ) $ (8,364 ) $ (56,362 ) $ 12,855 $ (43,507 ) (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 us. At March 31, 2016 , we held $21.4 million of cash from various counterparties and had no cash collateral posted. (b) - Included in other current assets, other current liabilities or deferred credits and other liabilities in our Consolidated Balance Sheets. December 31, 2015 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net (b) ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 38,921 $ — $ 7,253 $ 46,174 $ (42,414 ) $ 3,760 Physical contracts — — 3,591 3,591 — 3,591 Total derivative assets $ 38,921 $ — $ 10,844 $ 49,765 $ (42,414 ) $ 7,351 Derivative liabilities Commodity contracts Financial contracts $ (4,513 ) $ — $ (3,513 ) $ (8,026 ) $ 8,026 $ — Interest-rate contracts — (9,936 ) — (9,936 ) — (9,936 ) Total derivative liabilities $ (4,513 ) $ (9,936 ) $ (3,513 ) $ (17,962 ) $ 8,026 $ (9,936 ) (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 us. At December 31, 2015 , we held $34.4 million of cash from various counterparties and had no cash collateral posted. (b) - Included in other current assets or other current liabilities in our Consolidated Balance Sheets.
Reconciliation of Level 3 Fair Value Measurements	The following table sets forth a reconciliation of our Level 3 fair value measurements for the periods indicated: Three Months Ended March 31, Derivative Assets (Liabilities) 2016 2015 ( Thousands of dollars ) Net assets at beginning of period $ 7,331 $ 9,285 Total realized/unrealized gains (losses): Included in earnings (a) (745 ) 269 Included in other comprehensive income (loss) (6,552 ) (2,514 ) Net assets at end of period $ 34 $ 7,040 (a) - Included in commodity sales revenues in our Consolidated Statements of Income.

RISK MANAGEMENT AND HEDGING A30

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES (Tables)	3 Months Ended
	Mar. 31, 2016
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair value of derivatives	The following table sets forth the fair values of derivative instruments for the periods indicated: March 31, 2016 December 31, 2015 Assets (a) (Liabilities) (a) Assets (b) (Liabilities) (b) ( Thousands of dollars ) Derivatives designated as hedging instruments Commodity contracts Financial contracts $ 53,723 $ (4,577 ) $ 39,255 $ (1,440 ) Physical contracts 1,592 (1,940 ) 3,591 — Interest-rate contracts — (41,547 ) — (9,936 ) Total derivatives designated as hedging instruments 55,315 (48,064 ) 42,846 (11,376 ) Derivatives not designated as hedging instruments Commodity contracts Financial contracts 8,145 (8,298 ) 6,919 (6,586 ) Total derivatives not designated as hedging instruments 8,145 (8,298 ) 6,919 (6,586 ) Total derivatives $ 63,460 $ (56,362 ) $ 49,765 $ (17,962 ) (a) - Included on a net basis in other current assets, other current liabilities or deferred credits and other liabilities in our Consolidated Balance Sheets. (b) - Included on a net basis in other current assets or other current liabilities in our Consolidated Balance Sheets.
Notional amounts of derivative instruments	The following table sets forth the notional quantities for derivative instruments held for the periods indicated: March 31, 2016 December 31, 2015 Contract Type Purchased/ Payor Sold/ Receiver Purchased/ Payor Sold/ Receiver Derivatives designated as hedging instruments: Cash flow hedges Fixed price - Natural gas ( Bcf ) Futures and swaps — (39.9 ) — (27.1 ) - Natural gas ( Bcf ) Put options 57.1 — — — - Crude oil and NGLs ( MMBbl ) Futures, forwards and swaps — (4.2 ) — (2.3 ) - Propane ( MMBbl ) Put options 1.8 — — — Basis - Natural gas ( Bcf ) Futures and swaps — (39.9 ) — (27.1 ) Interest-rate contracts ( Millions of dollars ) Forward-starting swaps $ 1,400.0 $ — $ 400.0 $ — Derivatives not designated as hedging instruments: Fixed price - NGLs ( MMBbl ) Futures, forwards and swaps 2.1 (2.0 ) 0.6 (0.6 )
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: Three Months Ended Derivatives in Cash Flow Hedging Relationships March 31, 2016 2015 ( Thousands of dollars ) Commodity contracts $ 11,678 $ 10,019 Interest-rate contracts (31,611 ) (22,576 ) Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion) $ (19,933 ) $ (12,557 )
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 Hedging Relationships Location of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion) Three Months Ended March 31, 2016 2015 ( Thousands of dollars ) Commodity contracts Commodity sales revenues $ 14,499 $ 14,172 Interest-rate contracts Interest expense (3,819 ) (2,839 ) Total gain (loss) reclassified from accumulated other comprehensive loss into net income on derivatives (effective portion) $ 10,680 $ 11,333

LONG TERM DEBT LONG-TERM DEBT31

LONG TERM DEBT LONG-TERM DEBT (Tables)	3 Months Ended
	Mar. 31, 2016
Debt Instrument [Line Items]
Schedule of Debt [Table Text Block]	The following table sets forth our long-term debt for the periods indicated: March 31, December 31, 2016 2015 ( Thousands of dollars ) ONEOK Partners $650,000 at 3.25% due 2016 $ — $ 650,000 $450,000 at 6.15% due 2016 450,000 450,000 $400,000 at 2.0% due 2017 400,000 400,000 $425,000 at 3.2% due 2018 425,000 425,000 $1,000,000 term loan, variable rate, due 2019 1,000,000 — $500,000 at 8.625% due 2019 500,000 500,000 $300,000 at 3.8% due 2020 300,000 300,000 $900,000 at 3.375% due 2022 900,000 900,000 $425,000 at 5.0% due 2023 425,000 425,000 $500,000 at 4.9% due 2025 500,000 500,000 $600,000 at 6.65% due 2036 600,000 600,000 $600,000 at 6.85% due 2037 600,000 600,000 $650,000 at 6.125% due 2041 650,000 650,000 $400,000 at 6.2% due 2043 400,000 400,000 Guardian Pipeline Average 7.85% due 2022 49,995 51,907 Total long-term debt 7,199,995 6,851,907 Unamortized debt issuance costs and discounts (50,107 ) (48,945 ) Current maturities (457,650 ) (107,650 ) Long-term debt, excluding current maturities $ 6,692,238 $ 6,695,312

EQUITY (Tables)

EQUITY (Tables)	3 Months Ended
	Mar. 31, 2016
Equity [Abstract]
Schedule of distributions made to general or limited partner	The following table shows our distributions paid during the periods indicated: Three Months Ended March 31, 2016 2015 ( Thousands, except per unit amounts ) Distribution per unit $ 0.79 $ 0.79 General partner distributions $ 6,660 $ 5,914 Incentive distributions 100,538 89,279 Distributions to general partner 107,198 95,193 Limited partner distributions to ONEOK 90,323 73,302 Limited partner distributions to other unitholders 135,480 127,211 Total distributions paid $ 333,001 $ 295,706
Schedule of distributions declared to general or limited partner	Distributions are declared and paid within 45 days of the completion of each quarter. The following table shows our distributions declared for the periods indicated: Three Months Ended March 31, 2016 2015 ( Thousands, except per unit amounts ) Distribution per unit $ 0.79 $ 0.79 General partner distributions $ 6,660 $ 5,955 Incentive distributions 100,538 89,889 Distributions to general partner 107,198 95,844 Limited partner distributions to ONEOK 90,323 73,302 Limited partner distributions to other unitholders 135,480 128,583 Total distributions declared $ 333,001 $ 297,729

ACCUMULATED OTHER COMPREHENSI33

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ACCUMULATED OTHER COMPREHENSIVE INCOME (Tables)	3 Months Ended
	Mar. 31, 2016
Accumulated other comprehensive income (loss)	The following table sets forth the balance in accumulated other comprehensive loss for the period indicated: Unrealized Gains (Losses) on Risk- Management Assets/Liabilities Unrealized Gains (Losses) on Risk- Management Assets/Liabilities of Unconsolidated Affiliates Accumulated Other Comprehensive Loss ( Thousands of dollars ) January 1, 2016 $ (111,357 ) $ (1,925 ) $ (113,282 ) Other comprehensive income (loss) before reclassifications (19,933 ) (5,801 ) (25,734 ) Amounts reclassified from accumulated other comprehensive loss (10,680 ) — (10,680 ) Net current-period other comprehensive income (loss) attributable to ONEOK Partners (30,613 ) (5,801 ) (36,414 ) March 31, 2016 $ (141,970 ) $ (7,726 ) $ (149,696 )
Disclosure of Reclassification Amount [Text Block]	The following table sets forth the effect of reclassifications from accumulated other comprehensive loss in our Consolidated Statements of Income for the periods indicated: Details about Accumulated Other Components Three Months Ended Affected Line Item in the Income March 31, 2016 2015 ( Thousands of dollars ) Unrealized gains (losses) on risk-management assets/liabilities Commodity contracts $ 14,499 $ 14,172 Commodity sales revenues Interest-rate contracts (3,819 ) (2,839 ) Interest expense Total reclassifications for the period attributable to ONEOK Partners $ 10,680 $ 11,333 Net income attributable to ONEOK Partners

UNCONSOLIDATED AFFILIATES (Tabl

UNCONSOLIDATED AFFILIATES (Tables)	3 Months Ended
	Mar. 31, 2016
Equity In Net Earnings From Investments [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments [Table Text Block]	The following table sets forth our equity in net earnings from investments for the periods indicated: Three Months Ended March 31, 2016 2015 ( Thousands of dollars ) Northern Border Pipeline $ 18,674 $ 19,702 Overland Pass Pipeline Company 13,304 6,887 Other 936 4,332 Equity in net earnings from investments $ 32,914 $ 30,921
Summarized Financial Information Of Unconsolidated Affiliates [Member]
Schedule of Equity Method Investments [Line Items]
Equity Method Investments [Table Text Block]	The following table sets forth summarized combined financial information of our unconsolidated affiliates for the periods indicated: Three Months Ended March 31, 2016 2015 ( Thousands of dollars ) Income Statement Operating revenues $ 136,572 $ 129,581 Operating expenses $ 58,699 $ 57,579 Net income $ 72,037 $ 66,359 Distributions paid to us $ 46,553 $ 39,429

SEGMENTS (Tables)

SEGMENTS (Tables)	3 Months Ended
	Mar. 31, 2016
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Selected Financial Information by Reportable Segment	The following tables set forth certain selected financial information for our operating segments for the periods indicated: Three Months Ended March 31, 2016 Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Other and Eliminations Total ( Thousands of dollars ) Sales to unaffiliated customers $ 317,046 $ 1,371,425 $ 85,474 $ — $ 1,773,945 Intersegment revenues 114,965 115,965 499 (231,429 ) — Total revenues 432,011 1,487,390 85,973 (231,429 ) 1,773,945 Cost of sales and fuel (exclusive of items shown separately below) 266,300 1,156,950 3,932 (231,444 ) 1,195,738 Operating costs 69,606 73,182 27,513 79 170,380 Depreciation and amortization 41,851 40,706 11,179 — 93,736 (Gain) loss on sale of assets (1,245 ) 64 (2,964 ) — (4,145 ) Operating income $ 55,499 $ 216,488 $ 46,313 $ (64 ) $ 318,236 Equity in net earnings from investments $ 2,815 $ 13,347 $ 16,752 $ — $ 32,914 Investments in unconsolidated affiliates $ 73,769 $ 474,482 $ 380,958 $ — $ 929,209 Total assets $ 5,196,190 $ 8,016,245 $ 1,847,352 $ (115,065 ) $ 14,944,722 Noncontrolling interests in consolidated subsidiaries $ — $ 160,354 $ — $ — $ 160,354 Capital expenditures $ 141,497 $ 34,207 $ 17,948 $ 2,244 $ 195,896 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $281.8 million , of which $230.8 million related to sales within the segment, cost of sales and fuel of $106.8 million and operating income of $115.6 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $54.8 million , cost of sales and fuel of $5.6 million and operating income of $23.1 million . Three Months Ended March 31, 2015 Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Other and Eliminations Total ( Thousands of dollars ) Sales to unaffiliated customers $ 288,016 $ 1,434,813 $ 81,930 $ — $ 1,804,759 Intersegment revenues 167,607 61,279 1,619 (230,505 ) — Total revenues $ 455,623 $ 1,496,092 $ 83,549 $ (230,505 ) $ 1,804,759 Cost of sales and fuel (exclusive of items shown separately below) 330,931 1,228,865 14,426 (230,358 ) 1,343,864 Operating costs 69,209 82,246 27,242 (538 ) 178,159 Depreciation and amortization 35,797 39,294 10,756 — 85,847 (Gain) loss on sale of assets (1 ) 8 (1 ) — 6 Operating income $ 19,687 $ 145,679 $ 31,126 $ 391 $ 196,883 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 $ 4,887,938 $ 8,106,766 $ 1,815,235 $ (2,424 ) $ 14,807,515 Noncontrolling interests in consolidated subsidiaries $ 4,156 $ 162,958 $ — $ 15 $ 167,129 Capital expenditures $ 255,301 $ 73,466 $ 9,592 $ 4,677 $ 343,036 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $209.8 million , of which $165.3 million related to sales within the segment, cost of sales and fuel of $85.7 million and operating income of $64.9 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $54.2 million , cost of sales and fuel of $7.2 million and operating income of $21.7 million . Three Months Ended March 31, ( Unaudited ) 2016 2015 ( Thousands of dollars ) Segment Adjusted EBITDA: Natural Gas Gathering and Processing $ 100,035 $ 60,518 Natural Gas Liquids 270,169 192,655 Natural Gas Pipelines 74,339 70,712 Other 43 413 Depreciation and amortization (93,736 ) (85,847 ) Interest expense, net of capitalized interest (92,555 ) (80,709 ) Income taxes (2,028 ) (2,760 ) AFUDC and other 19 (7,950 ) Net income $ 256,286 $ 147,032

SUPPLEMENTAL CONDENSED CONSOL36

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION (Tables)	3 Months Ended
	Mar. 31, 2016
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Consolidating Statements of Income	Condensed Consolidating Statements of Income Three Months Ended March 31, 2016 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ 1,283.5 $ — $ 1,283.5 Services — — 490.4 — 490.4 Total revenues — — 1,773.9 — 1,773.9 Cost of sales and fuel (exclusive of items shown separately below) — — 1,195.7 — 1,195.7 Operating expenses — — 264.1 — 264.1 (Gain) loss on sale of assets — — (4.1 ) — (4.1 ) Operating income — — 318.2 — 318.2 Equity in net earnings from investments 253.5 253.5 14.2 (488.3 ) 32.9 Other income (expense), net 94.4 94.4 (0.2 ) (188.8 ) (0.2 ) Interest expense, net (94.4 ) (94.4 ) (92.6 ) 188.8 (92.6 ) Income before income taxes 253.5 253.5 239.6 (488.3 ) 258.3 Income taxes — — (2.0 ) — (2.0 ) Net income 253.5 253.5 237.6 (488.3 ) 256.3 Less: Net income attributable to noncontrolling interests — — 2.8 — 2.8 Net income attributable to ONEOK Partners, L.P. $ 253.5 $ 253.5 $ 234.8 $ (488.3 ) $ 253.5 Three Months Ended March 31, 2015 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ 1,435.7 $ — $ 1,435.7 Services — — 369.1 — 369.1 Total revenues — — 1,804.8 — 1,804.8 Cost of sales and fuel (exclusive of items shown separately below) — — 1,343.9 — 1,343.9 Operating expenses — — 264.0 — 264.0 (Gain) loss on sale of assets — — — — — Operating income — — 196.9 — 196.9 Equity in net earnings from investments 145.6 145.6 11.3 (271.6 ) 30.9 Other income (expense), net 86.8 86.8 2.7 (173.6 ) 2.7 Interest expense, net (86.8 ) (86.8 ) (80.7 ) 173.6 (80.7 ) Income before income taxes 145.6 145.6 130.2 (271.6 ) 149.8 Income taxes — — (2.8 ) — (2.8 ) Net income 145.6 145.6 127.4 (271.6 ) 147.0 Less: Net income attributable to noncontrolling interests — — 1.4 — 1.4 Net income attributable to ONEOK Partners, L.P. $ 145.6 $ 145.6 $ 126.0 $ (271.6 ) $ 145.6
Condensed Consolidating Statements of Comprehensive Income	Condensed Consolidating Statements of Comprehensive Income Three Months Ended March 31, 2016 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 253.5 $ 253.5 $ 237.6 $ (488.3 ) $ 256.3 Other comprehensive income (loss) Unrealized gains (losses) on derivatives (19.9 ) 11.7 11.7 (23.4 ) (19.9 ) Realized (gains) losses on derivatives recognized in net income (10.7 ) (14.5 ) (14.5 ) 29.0 (10.7 ) Other comprehensive income (loss) on investments in unconsolidated affiliates (5.8 ) (5.8 ) (5.8 ) 11.6 (5.8 ) Total other comprehensive income (loss) (36.4 ) (8.6 ) (8.6 ) 17.2 (36.4 ) Comprehensive income 217.1 244.9 229.0 (471.1 ) 219.9 Less: Comprehensive income attributable to noncontrolling interests — — 2.8 — 2.8 Comprehensive income attributable to ONEOK Partners, L.P. $ 217.1 $ 244.9 $ 226.2 $ (471.1 ) $ 217.1 Three Months Ended March 31, 2015 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 145.6 $ 145.6 $ 127.4 $ (271.6 ) $ 147.0 Other comprehensive income (loss) Unrealized gains (losses) on derivatives (12.6 ) 10.0 10.0 (20.0 ) (12.6 ) Realized (gains) losses on derivatives recognized in net income (11.3 ) (14.2 ) (14.2 ) 28.4 (11.3 ) Total other comprehensive income (loss) (23.9 ) (4.2 ) (4.2 ) 8.4 (23.9 ) Comprehensive income 121.7 141.4 123.2 (263.2 ) 123.1 Less: Comprehensive income attributable to noncontrolling interests — — 1.4 — 1.4 Comprehensive income attributable to ONEOK Partners, L.P. $ 121.7 $ 141.4 $ 121.8 $ (263.2 ) $ 121.7
Condensed Consolidating Balance Sheets	Condensed Consolidating Balance Sheets March 31, 2016 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total Assets ( Millions of dollars ) Current assets Cash and cash equivalents $ — $ 9.9 $ — $ — $ 9.9 Accounts receivable, net — — 520.8 — 520.8 Affiliate receivables — — 3.6 — 3.6 Natural gas and natural gas liquids in storage — — 156.1 — 156.1 Other current assets 0.4 — 165.7 — 166.1 Total current assets 0.4 9.9 846.2 — 856.5 Property, plant and equipment Property, plant and equipment — — 14,448.9 — 14,448.9 Accumulated depreciation and amortization — — 2,126.4 — 2,126.4 Net property, plant and equipment — — 12,322.5 — 12,322.5 Investments and other assets Intercompany notes receivable 10,383.8 7,704.4 — (18,088.2 ) — Other assets 3,505.9 6,175.4 1,406.4 (9,322.0 ) 1,765.7 Total investments and other assets 13,889.7 13,879.8 1,406.4 (27,410.2 ) 1,765.7 Total assets $ 13,890.1 $ 13,889.7 $ 14,575.1 $ (27,410.2 ) $ 14,944.7 Liabilities and equity Current liabilities Current maturities of long-term debt $ 450.0 $ — $ 7.7 $ — $ 457.7 Short-term borrowings 444.6 — — — 444.6 Accounts payable — — 513.5 — 513.5 Affiliate payables — — 20.1 — 20.1 Other current liabilities 121.7 — 151.7 — 273.4 Total current liabilities 1,016.3 — 693.0 — 1,709.3 Intercompany debt — 10,383.8 7,704.4 (18,088.2 ) — Long-term debt, excluding current maturities 6,649.9 — 42.3 — 6,692.2 Deferred credits and other liabilities 6.6 — 158.9 — 165.5 Commitments and contingencies Equity Equity excluding noncontrolling interests in consolidated subsidiaries 6,217.3 3,505.9 5,816.1 (9,322.0 ) 6,217.3 Noncontrolling interests in consolidated subsidiaries — — 160.4 — 160.4 Total equity 6,217.3 3,505.9 5,976.5 (9,322.0 ) 6,377.7 Total liabilities and equity $ 13,890.1 $ 13,889.7 $ 14,575.1 $ (27,410.2 ) $ 14,944.7 December 31, 2015 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total Assets ( Millions of dollars ) Current assets Cash and cash equivalents $ — $ 5.1 $ — $ — $ 5.1 Accounts receivable, net — — 593.4 — 593.4 Affiliate receivables — — 8.0 — 8.0 Natural gas and natural gas liquids in storage — — 128.1 — 128.1 Other current assets 4.1 — 144.5 — 148.6 Total current assets 4.1 5.1 874.0 — 883.2 Property, plant and equipment Property, plant and equipment — — 14,307.5 — 14,307.5 Accumulated depreciation and amortization — — 2,050.7 — 2,050.7 Net property, plant and equipment — — 12,256.8 — 12,256.8 Investments and other assets Intercompany notes receivable 10,144.9 7,781.8 — (17,926.7 ) — Other assets 3,594.0 5,952.0 1,425.2 (9,183.6 ) 1,787.6 Total investments and other assets 13,738.9 13,733.8 1,425.2 (27,110.3 ) 1,787.6 Total assets $ 13,743.0 $ 13,738.9 $ 14,556.0 $ (27,110.3 ) $ 14,927.6 Liabilities and equity Current liabilities Current maturities of long-term debt $ 100.0 $ — $ 7.7 $ — $ 107.7 Short-term borrowings 546.3 — — — 546.3 Accounts payable — — 605.4 — 605.4 Affiliate payables — — 27.1 — 27.1 Other current liabilities 112.5 — 181.4 — 293.9 Total current liabilities 758.8 — 821.6 — 1,580.4 Intercompany debt — 10,144.9 7,781.8 (17,926.7 ) — Long-term debt, excluding current maturities 6,651.0 — 44.3 — 6,695.3 Deferred credits and other liabilities — — 154.6 — 154.6 Commitments and contingencies Equity Equity excluding noncontrolling interests in consolidated subsidiaries 6,333.2 3,594.0 5,589.6 (9,183.6 ) 6,333.2 Noncontrolling interests in consolidated subsidiaries — — 164.1 — 164.1 Total equity 6,333.2 3,594.0 5,753.7 (9,183.6 ) 6,497.3 Total liabilities and equity $ 13,743.0 $ 13,738.9 $ 14,556.0 $ (27,110.3 ) $ 14,927.6
Condensed Consolidating Statements of Cash Flows	Condensed Consolidating Statements of Cash Flows Three Months Ended March 31, 2016 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 318.8 $ 18.7 $ 261.8 $ (333.0 ) $ 266.3 Investing activities Capital expenditures — — (195.9 ) — (195.9 ) Other investing activities — 3.2 23.2 — 26.4 Cash provided by (used in) investing activities — 3.2 (172.7 ) — (169.5 ) Financing activities Cash distributions: General and limited partners (333.0 ) (333.0 ) — 333.0 (333.0 ) Noncontrolling interests — — (2.5 ) — (2.5 ) Intercompany borrowings (advances), net (231.2 ) 315.9 (84.7 ) — — Borrowing (repayment) of short-term borrowings, net (101.8 ) — — — (101.8 ) Issuance of long-term debt, net of discounts 1,000.0 — — — 1,000.0 Debt financing costs (2.8 ) — — — (2.8 ) Repayment of long-term debt (650.0 ) — (1.9 ) — (651.9 ) Cash provided by (used in) financing activities (318.8 ) (17.1 ) (89.1 ) 333.0 (92.0 ) Change in cash and cash equivalents — 4.8 — — 4.8 Cash and cash equivalents at beginning of period — 5.1 — — 5.1 Cash and cash equivalents at end of period $ — $ 9.9 $ — $ — $ 9.9 Three Months Ended March 31, 2015 ( Unaudited ) Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 218.8 $ 19.7 $ 122.3 $ (295.7 ) $ 65.1 Investing activities Capital expenditures — — (343.0 ) — (343.0 ) Other investing activities — 1.7 8.3 — 10.0 Cash provided by (used in) investing activities — 1.7 (334.7 ) — (333.0 ) Financing activities Cash distributions: General and limited partners (295.7 ) (295.7 ) — 295.7 (295.7 ) Noncontrolling interests — — (2.2 ) — (2.2 ) Intercompany borrowings (advances), net (538.8 ) 322.3 216.5 — — Borrowing (repayment) of short-term borrowings, net (229.8 ) — — — (229.8 ) Issuance of long-term debt, net of discounts 798.9 — — — 798.9 Debt financing costs (7.9 ) — — — (7.9 ) Repayment of long-term debt — — (1.9 ) — (1.9 ) Issuance of common units, net of issuance costs 53.4 — — — 53.4 Contribution from general partner 1.1 — — — 1.1 Cash provided by (used in) financing activities (218.8 ) 26.6 212.4 295.7 315.9 Change in cash and cash equivalents — 48.0 — — 48.0 Cash and cash equivalents at beginning of period — 42.5 — — 42.5 Cash and cash equivalents at end of period $ — $ 90.5 $ — $ — $ 90.5

FAIR VALUE MEASUREMENTS - Part

FAIR VALUE MEASUREMENTS - Part 1 (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term debt, Fair Value	$ 6,900,000	$ 6,200,000
Long-term debt, Book Value	7,100,000	6,800,000
Cash collateral held under master netting arrangements	21,400	34,400
Cash collateral posted under master netting arrangements	0	0
Fair Value, Measurements, Recurring [Member]
Derivative assets
Commodity contracts - financial	27,607	3,760
Commodity contracts - physical	1,592	3,591
Total derivative assets	29,199	7,351
Derivative liabilities
Commodity contracts - financial	(20)	0
Commodity contracts - physical	(1,940)
Interest-rate contracts	(41,547)	(9,936)
Total derivative liabilities	(43,507)	(9,936)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative assets
Commodity contracts - financial	55,062	38,921
Commodity contracts - physical	0	0
Total derivative assets	55,062	38,921
Derivative liabilities
Commodity contracts - financial	(6,451)	(4,513)
Commodity contracts - physical	0
Interest-rate contracts	0	0
Total derivative liabilities	(6,451)	(4,513)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative assets
Commodity contracts - financial	0	0
Commodity contracts - physical	0	0
Total derivative assets	0	0
Derivative liabilities
Commodity contracts - financial	0	0
Commodity contracts - physical	0
Interest-rate contracts	(41,547)	(9,936)
Total derivative liabilities	(41,547)	(9,936)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Derivative assets
Commodity contracts - financial	6,806	7,253
Commodity contracts - physical	1,592	3,591
Total derivative assets	8,398	10,844
Derivative liabilities
Commodity contracts - financial	(6,424)	(3,513)
Commodity contracts - physical	(1,940)
Interest-rate contracts	0	0
Total derivative liabilities	(8,364)	(3,513)
Fair Value, Measurements, Recurring [Member] | Total Gross [Member]
Derivative assets
Commodity contracts - financial	61,868	46,174
Commodity contracts - physical	1,592	3,591
Total derivative assets	63,460	49,765
Derivative liabilities
Commodity contracts - financial	(12,875)	(8,026)
Commodity contracts - physical	(1,940)
Interest-rate contracts	(41,547)	(9,936)
Total derivative liabilities	(56,362)	(17,962)
Fair Value, Measurements, Recurring [Member] | Netting [Member]
Derivative assets
Commodity contracts - financial	(34,261)	(42,414)
Commodity contracts - physical	0	0
Total derivative assets	(34,261)	(42,414)
Derivative liabilities
Commodity contracts - financial	12,855	8,026
Commodity contracts - physical	0
Interest-rate contracts	0	0
Total derivative liabilities	$ 12,855	$ 8,026

FAIR VALUE MEASUREMENTS - Par38

FAIR VALUE MEASUREMENTS - Part 2 (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Fair Value, Assets And Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Transfers between levels	$ 0	$ 0
Net assets at beginning of period	7,331	9,285
Total realized/unrealized gains (losses):
Included in earnings	(745)	269
Included in other comprehensive income (loss)	(6,552)	(2,514)
Net assets at end of period	$ 34	$ 7,040

RISK MANAGEMENT AND HEDGING A39

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES Part 1 (Details) - USD ($)	Mar. 31, 2016	Dec. 31, 2015
Derivative [Line Items]
Assets	$ 63,460,000	$ 49,765,000
(Liabilities)	(56,362,000)	(17,962,000)
Derivative, Net Liability Position, Aggregate Fair Value	0
Natural Gas Pipelines [Member]
Derivative [Line Items]
Derivative, Fair Value, Net	0	0
Designated as Hedging Instrument [Member]
Derivative [Line Items]
Assets	55,315,000	42,846,000
(Liabilities)	(48,064,000)	(11,376,000)
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Assets	0	0
(Liabilities)	(41,547,000)	(9,936,000)
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Assets	8,145,000	6,919,000
(Liabilities)	(8,298,000)	(6,586,000)
Financial Derivative Instrument [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivative [Line Items]
Assets	53,723,000	39,255,000
(Liabilities)	(4,577,000)	(1,440,000)
Financial Derivative Instrument [Member] | Not Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivative [Line Items]
Assets	8,145,000	6,919,000
(Liabilities)	(8,298,000)	(6,586,000)
Physical Derivative Instrument [Member] | Designated as Hedging Instrument [Member] | Commodity Contract [Member]
Derivative [Line Items]
Assets	1,592,000	3,591,000
(Liabilities)	$ (1,940,000)	$ 0

RISK MANAGEMENT AND HEDGING A40

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES, Part 2 (Details) $ in Millions	Mar. 31, 2016USD ($)MMcfMMBbls	Dec. 31, 2015USD ($)MMcfMMBbls
Forward Contracts [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member] | LIBOR Based Interest Payments [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount | $	$ 1,000
Forward Contracts [Member] | Cash Flow Hedging [Member] | Interest Rate Contract [Member] | Forecasted Debt Issuances [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount | $	$ 400
Futures and swaps [Member] | Designated as Hedging Instrument [Member] | Fixed Price [Member] | Purchased [Member] | Natural Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | MMcf	0	0
Futures and swaps [Member] | Designated as Hedging Instrument [Member] | Fixed Price [Member] | Sold [Member] | Natural Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | MMcf	(39,900)	(27,100)
Futures and swaps [Member] | Designated as Hedging Instrument [Member] | Basis [Member] | Purchased [Member] | Natural Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | MMcf	0	0
Futures and swaps [Member] | Designated as Hedging Instrument [Member] | Basis [Member] | Sold [Member] | Natural Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | MMcf	(39,900)	(27,100)
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Purchased [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount | $	$ 1,400	$ 400
Interest Rate Contract [Member] | Designated as Hedging Instrument [Member] | Sold [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Notional Amount | $	$ 0	$ 0
Options [Member] | Designated as Hedging Instrument [Member] | Fixed Price [Member] | Purchased [Member] | Natural Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | MMcf	57,100	0
Options [Member] | Designated as Hedging Instrument [Member] | Fixed Price [Member] | Purchased [Member] | Propane [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | MMBbls	1.8	0
Options [Member] | Designated as Hedging Instrument [Member] | Fixed Price [Member] | Sold [Member] | Natural Gas [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | MMcf	0	0
Options [Member] | Designated as Hedging Instrument [Member] | Fixed Price [Member] | Sold [Member] | Propane [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | MMBbls	0	0
Futures, forwards and swaps [Member] | Designated as Hedging Instrument [Member] | Fixed Price [Member] | Purchased [Member] | Crude Oil and NGL [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | MMBbls	0	0
Futures, forwards and swaps [Member] | Designated as Hedging Instrument [Member] | Fixed Price [Member] | Sold [Member] | Crude Oil and NGL [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | MMBbls	(4.2)	(2.3)
Futures, forwards and swaps [Member] | Not Designated as Hedging Instrument [Member] | Fixed Price [Member] | Purchased [Member] | Crude Oil and NGL [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | MMBbls	2.1	0.6
Futures, forwards and swaps [Member] | Not Designated as Hedging Instrument [Member] | Fixed Price [Member] | Sold [Member] | Crude Oil and NGL [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Nonmonetary Notional Amount | MMBbls	(2)	(0.6)

RISK MANAGEMENT AND HEDGING A41

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES Part 3 (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (149,696)		$ (113,282)
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(19,933)	$ (12,557)
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	10,680	11,333
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	0	0
Commodity Contract [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized Gain (Loss) On Cash Flow Hedges Net Of Tax Accumulated Other Comprehensive Income Loss	38,700
Price Risk Cash Flow Hedge Unrealized Gain (Loss) to be Reclassified During Next 12 Months	38,700
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	11,678	10,019
Commodity Contract [Member] | Sales [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	14,499	14,172
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.	(137,800)
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	(15,900)
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(31,611)	(22,576)
Interest Rate Contract [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net	$ (3,819)	$ (2,839)

SHORT-TERM BORROWINGS (Details)

SHORT-TERM BORROWINGS (Details) $ in Millions	3 Months Ended
	Mar. 31, 2016USD ($)Rate
Partnership Credit Agreement [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	$ 2,400
Line of Credit Facility Letters of Credit Sublimit	100
Line of Credit Facility Swingline Sublimit	150
Letters of credit issued	14
Borrowings outstanding under our Partnership Credit Agreement	0
Line of Credit Facility, Remaining Borrowing Capacity	$ 1,900
Line of Credit Facility, Interest Rate Description	borrowings, if any, will accrue at LIBOR plus 117.5 basis points
Annual 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
Indebtedness To Adjusted EBITDA From Acquisitions Maximum	5.5
Indebtedness To Adjusted EBITDA Current	4.2
Commercial Paper [Member]
Line of Credit Facility [Line Items]
Commercial paper outstanding	$ 445
Maximum Amount Of Commercial Paper	$ 2,400
Short-term Debt, Weighted Average Interest Rate | Rate	1.36%

LONG TERM DEBT LONG-TERM DEBT43

LONG TERM DEBT LONG-TERM DEBT (Details) - USD ($) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2016	Dec. 31, 2015
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 7,199,995	$ 6,851,907
Unamortized debt issuance costs and discounts	(50,107)	(48,945)
Current maturities	(457,650)	(107,650)
Long-term debt, excluding current maturities	6,692,238	6,695,312
Partnership Interest [Member] | Senior Notes [Member]
Debt Instrument [Line Items]
Senior Notes, Noncurrent		800,000
Proceeds from Debt, Net of Issuance Costs		792,300
Partnership Interest [Member] | Notes Payable due 2016 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 450,000	450,000
Debt Instrument, Interest Rate, Stated Percentage	6.15%
Partnership Interest [Member] | Note Payable from Public Offering Due 2016 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 0	650,000
Debt Instrument, Interest Rate, Stated Percentage	3.25%
Partnership Interest [Member] | Note Payable from Public Offering Due 2017 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 400,000	400,000
Debt Instrument, Interest Rate, Stated Percentage	2.00%
Partnership Interest [Member] | Note Payable from Public Offering Due 2018 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 425,000	425,000
Debt Instrument, Interest Rate, Stated Percentage	3.20%
Partnership Interest [Member] | Term Loan Agreement [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 1,000,000	0
Delayed-Draw Unsecured Senior Term Loan	$ 1,000,000
Debt Instrument, Interest Rate Terms	LIBOR plus 130 basis points
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate	1.74%
Proceeds from Debt, Net of Issuance Costs	$ 1,000,000
Partnership Interest [Member] | Notes Payables due 2019 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 500,000	500,000
Debt Instrument, Interest Rate, Stated Percentage	8.625%
Partnership Interest [Member] | Note Payable from Public Offering Due 2020 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 300,000	$ 300,000
Debt Instrument, Interest Rate, Stated Percentage	3.80%	3.80%
Partnership Interest [Member] | Note Payable 2 from Public Offering Due 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 900,000	$ 900,000
Debt Instrument, Interest Rate, Stated Percentage	3.375%
Partnership Interest [Member] | Note Payable from Public Offering Due 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 425,000	425,000
Debt Instrument, Interest Rate, Stated Percentage	5.00%
Partnership Interest [Member] | Note Payable from Public Offering Due 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 500,000	$ 500,000
Debt Instrument, Interest Rate, Stated Percentage	4.90%	4.90%
Partnership Interest [Member] | Notes Payables due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 600,000	$ 600,000
Debt Instrument, Interest Rate, Stated Percentage	6.65%
Partnership Interest [Member] | Notes Payables due 2037 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 600,000	600,000
Debt Instrument, Interest Rate, Stated Percentage	6.85%
Partnership Interest [Member] | Note Payable from Public Offering Due 2041 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 650,000	650,000
Debt Instrument, Interest Rate, Stated Percentage	6.125%
Partnership Interest [Member] | Note Payable from Public Offering Due 2043 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 400,000	400,000
Debt Instrument, Interest Rate, Stated Percentage	6.20%
Guardian Pipeline [Member] | Notes Payables 1 due 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 49,995	$ 51,907
Guardian Interest Rate	7.85%

EQUITY (Details)

EQUITY (Details) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Partnership Capital Distributions [Line Items]
Key Provisions of Operating or Partnership Agreement, Description	Partnership Agreement - Available cash, as defined in our Partnership Agreement generally will be distributed to our general partner and limited partners according to their partnership percentages of 2 percent and 98 percent, respectively. Our 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 our Partnership Agreement, our 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.
Number of common units owned by related party (in number of units)	41.3
General partnership ownership interest (in hundredths)	41.20%
Partners' Capital Account, Contributions		$ 1,100
Aggregate Amount Of Common Units Available For Issuance And Sale Under The Equity Distribution Agreement	$ 650,000
Remaining Capacity of At The Market Equity Program	138,000
Total distributions	$ 335,501	$ 297,952
Distribution Declared [Member]
Partnership Capital Distributions [Line Items]
Distribution Made To Member Or Limited Partner Annualized Quarterly Distribution	$ 3.16
Distribution Made to Member or Limited Partner, Distribution Date	May 13, 2016
Distribution Made to Member or Limited Partner, Date of Record	May 2, 2016
Distribution per unit	$ 0.790	$ 0.79
Total distributions	$ 333,001	$ 297,729
Distribution Declared [Member] | General Partner [Member]
Partnership Capital Distributions [Line Items]
General Partner Distributions	6,660	5,955
Incentive distributions	100,538	89,889
Distributions to general partner	107,198	95,844
Distribution Declared [Member] | Limited Partner [Member]
Partnership Capital Distributions [Line Items]
Limited partner distributions to other unitholders	135,480	128,583
Distribution Declared [Member] | ONEOK [Member]
Partnership Capital Distributions [Line Items]
Limited partner distributions to ONEOK	$ 90,323	$ 73,302
Distribution Paid [Member]
Partnership Capital Distributions [Line Items]
Distribution per unit	$ 0.79	$ 0.79
Total distributions	$ 333,001	$ 295,706
Distribution Paid [Member] | General Partner [Member]
Partnership Capital Distributions [Line Items]
General Partner Distributions	6,660	5,914
Incentive distributions	100,538	89,279
Distributions to general partner	107,198	95,193
Distribution Paid [Member] | Limited Partner [Member]
Partnership Capital Distributions [Line Items]
Limited partner distributions to other unitholders	135,480	127,211
Distribution Paid [Member] | ONEOK [Member]
Partnership Capital Distributions [Line Items]
Limited partner distributions to ONEOK	$ 90,323	$ 73,302
Private Placement [Member]
Partnership Capital Distributions [Line Items]
Number of common units to related party in a private placement (in number of units)			21.5
Partners Capital Account Units Sold Under Equity Distribution Agreement			3.3
Partners' Capital Account, Contributions			$ 15,300
Per Unit Offering Price Under Private Placement			$ 30.17
Proceeds from sale of interest in partnership units			$ 749,000
Issued Under Equity Distribution Agreement [Member]
Partnership Capital Distributions [Line Items]
Partners Capital Account Units Sold Under Equity Distribution Agreement	0	1.7	10.5
Proceeds from sale of interest in partnership units		$ 71,600	$ 381,600
Noncontrolling Interest [Member]
Partnership Capital Distributions [Line Items]
Partners' Capital Account, Contributions		0
Total distributions	$ 2,500	$ 2,246
General Partner [Member]
Partnership Capital Distributions [Line Items]
General partnership ownership interest (in hundredths)	2.00%

ACCUMULATED OTHER COMPREHENSI45

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Unrealized gains (losses) on risk management assets/liabilities - January 1, 2016	$ (111,357)
Investments in unconsolidated affiliates - January 1, 2016	(1,925)
Accumulated other comprehensive loss - January 1, 2016	(113,282)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax	(19,933)	$ (12,557)
Other Comprehensive Income (Loss), Amount Attributable to Equity Method Investments, before Reclassification Adjustments, Net of Tax	(5,801)
Other comprehensive income (loss) before reclassifications	(25,734)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	(10,680)	(11,333)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Other Comprehensive Income Attributable to Equity Method Investments, Net of Tax	0
Other Comprehensive Income (Loss), Reclassification Adjustment included in Net Income, Net of Tax	(10,680)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent	(30,613)
Other comprehensive income (loss) on investment in unconsolidated affiliates	(5,801)	0
Net current-period other comprehensive income (loss) attributable to ONEOK Partners, L.P.	(36,414)	(23,890)
Unrealized gains (losses) on risk management assets/liabilities - March 31, 2016	(141,970)
Investments in unconsolidated affiliates - March 31, 2016	(7,726)
Accumulated other comprehensive loss - March 31, 2016	(149,696)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax	(10,680)	(11,333)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Commodity Contract [Member]
Amounts reclassified from accumulated other comprehensive income (loss)	(14,499)	(14,172)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate Contract [Member]
Amounts reclassified from accumulated other comprehensive income (loss)	$ 3,819	$ 2,839

LIMITED PARTNERS' NET INCOME 46

LIMITED PARTNERS' NET INCOME PER UNIT (Details)	3 Months Ended
	Mar. 31, 2016Rate
Schedule of Equity Method Investments [Line Items]
Number of days notice of withdrawal of waiver	90
General partnership ownership interest (in hundredths)	41.20%

UNCONSOLIDATED AFFILIATES (Deta

UNCONSOLIDATED AFFILIATES (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Equity in net earnings (loss) from investments	$ 32,914	$ 30,921
Accounts Payable, Related Parties, Current	11,800			$ 8,000
Income Statement [Abstract]
Operating revenues	136,572	129,581
Operating expenses	58,699	57,579
Net income	72,037	66,359
Proceeds from Equity Method Investment, Dividends or Distributions	46,553	39,429
Northern Border Pipeline [Member]
Schedule of Equity Method Investments [Line Items]
Equity in net earnings (loss) from investments	18,674	19,702
Overland Pass Pipeline Company [Member]
Schedule of Equity Method Investments [Line Items]
Equity in net earnings (loss) from investments	13,304	6,887
Other Unconsolidated Affiliate [Member]
Schedule of Equity Method Investments [Line Items]
Equity in net earnings (loss) from investments	936	4,332
Roadrunner Gas Transmission [Member]
Schedule of Equity Method Investments [Line Items]
Payments to Acquire Equity Method Investments	0
Unconsolidated Affiliates [Member]
Schedule of Equity Method Investments [Line Items]
Costs and operating expenses with equity method investees	$ 33,600	$ 19,900
Scenario, Forecast [Member] | Roadrunner Gas Transmission [Member]
Schedule of Equity Method Investments [Line Items]
Payments to Acquire Equity Method Investments			$ 50,000

RELATED-PARTY TRANSACTIONS (Det

RELATED-PARTY TRANSACTIONS (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Related Party Transaction [Line Items]
Partners' Capital Account, Contributions		$ 1,100
ONEOK [Member]
Related Party Transaction [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	$ 87,700	89,500
General Partner [Member]
Related Party Transaction [Line Items]
Partners' Capital Account, Contributions		$ 1,100

SEGMENTS Part 1 (Details)

SEGMENTS Part 1 (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Segment disclosure [Abstract]
Disclosure of Major Customers	For the three months ended March 31, 2016, we had one customer, BP p.l.c. or its affiliates, from which we received $221.2 million in total revenues from all of our operating segments, or approximately 12 percent of our consolidated revenues.	For the three months ended March 31, 2015, we had one customer, BP p.l.c. or its affiliates, from which we received $184.9 million in total revenues from all of our operating segments, or approximately 10 percent of our consolidated revenues.
Total revenues	$ 1,773,945	$ 1,804,759
Cost of sales and fuel (exclusive of items shown separately below)	1,195,738	1,343,864
Operating costs	170,380	178,159
Depreciation and amortization	93,736	85,847
(Gain) loss on sale of assets	(4,145)	6
Operating income	318,236	196,883
Equity in net earnings from investments	32,914	30,921
Investments in unconsolidated affiliates	929,209	1,124,204	$ 948,221
Total assets	14,944,722	14,807,515	14,927,586
Noncontrolling interests in consolidated subsidiaries	160,354	167,129	$ 164,125
Capital expenditures	195,896	343,036
Natural Gas Gathering and Processing [Member]
Segment disclosure [Abstract]
Total revenues	432,011	455,623
Cost of sales and fuel (exclusive of items shown separately below)	266,300	330,931
Operating costs	69,606	69,209
Depreciation and amortization	41,851	35,797
(Gain) loss on sale of assets	(1,245)	(1)
Operating income	55,499	19,687
Equity in net earnings from investments	2,815	4,239
Investments in unconsolidated affiliates	73,769	255,419
Total assets	5,196,190	4,887,938
Noncontrolling interests in consolidated subsidiaries	0	4,156
Capital expenditures	141,497	255,301
Natural Gas Liquids [Member]
Segment disclosure [Abstract]
Total revenues	1,487,390	1,496,092
Cost of sales and fuel (exclusive of items shown separately below)	1,156,950	1,228,865
Operating costs	73,182	82,246
Depreciation and amortization	40,706	39,294
(Gain) loss on sale of assets	64	8
Operating income	216,488	145,679
Equity in net earnings from investments	13,347	6,980
Investments in unconsolidated affiliates	474,482	483,257
Total assets	8,016,245	8,106,766
Noncontrolling interests in consolidated subsidiaries	160,354	162,958
Capital expenditures	34,207	73,466
Natural Gas Liquids [Member] | Natural Gas Liquids Regulated [Member]
Segment disclosure [Abstract]
Total revenues	281,800	209,800
Cost of sales and fuel (exclusive of items shown separately below)	106,800	85,700
Operating income	115,600	64,900
Natural Gas Pipelines [Member]
Segment disclosure [Abstract]
Total revenues	85,973	83,549
Cost of sales and fuel (exclusive of items shown separately below)	3,932	14,426
Operating costs	27,513	27,242
Depreciation and amortization	11,179	10,756
(Gain) loss on sale of assets	(2,964)	(1)
Operating income	46,313	31,126
Equity in net earnings from investments	16,752	19,702
Investments in unconsolidated affiliates	380,958	385,528
Total assets	1,847,352	1,815,235
Noncontrolling interests in consolidated subsidiaries	0	0
Capital expenditures	17,948	9,592
Natural Gas Pipelines [Member] | Natural Gas Pipelines Regulated [Member]
Segment disclosure [Abstract]
Total revenues	54,800	54,200
Cost of sales and fuel (exclusive of items shown separately below)	5,600	7,200
Operating income	23,100	21,700
Other and Eliminations
Segment disclosure [Abstract]
Total revenues	(231,429)	(230,505)
Cost of sales and fuel (exclusive of items shown separately below)	(231,444)	(230,358)
Operating costs	79	(538)
Depreciation and amortization	0	0
(Gain) loss on sale of assets	0	0
Operating income	(64)	391
Equity in net earnings from investments	0	0
Investments in unconsolidated affiliates	0	0
Total assets	(115,065)	(2,424)
Noncontrolling interests in consolidated subsidiaries	0	15
Capital expenditures	2,244	4,677
Unaffiliated entity [Member]
Segment disclosure [Abstract]
Total revenues	1,773,945	1,804,759
Unaffiliated entity [Member] | Natural Gas Gathering and Processing [Member]
Segment disclosure [Abstract]
Total revenues	317,046	288,016
Unaffiliated entity [Member] | Natural Gas Liquids [Member]
Segment disclosure [Abstract]
Total revenues	1,371,425	1,434,813
Unaffiliated entity [Member] | Natural Gas Pipelines [Member]
Segment disclosure [Abstract]
Total revenues	85,474	81,930
Unaffiliated entity [Member] | Other and Eliminations
Segment disclosure [Abstract]
Total revenues	0	0
Operating Segments [Member]
Segment disclosure [Abstract]
Total revenues	0	0
Operating Segments [Member] | Natural Gas Gathering and Processing [Member]
Segment disclosure [Abstract]
Total revenues	114,965	167,607
Operating Segments [Member] | Natural Gas Liquids [Member]
Segment disclosure [Abstract]
Total revenues	115,965	61,279
Operating Segments [Member] | Natural Gas Liquids [Member] | Natural Gas Liquids Regulated [Member]
Segment disclosure [Abstract]
Total revenues	230,800	165,300
Operating Segments [Member] | Natural Gas Pipelines [Member]
Segment disclosure [Abstract]
Total revenues	499	1,619
Operating Segments [Member] | Other and Eliminations
Segment disclosure [Abstract]
Total revenues	$ (231,429)	$ (230,505)

SEGMENTS SEGMENTS Part 2 (Detai

SEGMENTS SEGMENTS Part 2 (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Segment Reporting Information [Line Items]
Depreciation and amortization	$ (93,736)	$ (85,847)
Interest expense (net of capitalized interest)	(92,555)	(80,709)
Income taxes	(2,028)	(2,760)
AFUDC and other	19	(7,950)
Net income	256,286	147,032
Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	100,035	60,518
Depreciation and amortization	(41,851)	(35,797)
Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	270,169	192,655
Depreciation and amortization	(40,706)	(39,294)
Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	74,339	70,712
Depreciation and amortization	(11,179)	(10,756)
Other [Member]
Segment Reporting Information [Line Items]
Adjusted EBITDA	$ 43	$ 413

SUPPLEMENTAL CONDENSED CONSOL51

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION, Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Commodity sales	$ 1,283,511	$ 1,435,716
Services	490,434	369,043
Total revenues	1,773,945	1,804,759
Cost of sales and fuel (exclusive of items shown separately below)	1,195,738	1,343,864
(Gain) loss on sale of assets	(4,145)	6
Operating income	318,236	196,883
Equity in net earnings from investments	32,914	30,921
Interest expense, net	(92,555)	(80,709)
Income before income taxes	258,314	149,792
Income taxes	(2,028)	(2,760)
Net income	256,286	147,032
Less: Net income attributable to noncontrolling interests	2,769	1,438
Net income attributable to ONEOK Partners, L.P.	253,517	145,594
Parent [member]
Condensed Financial Statements, Captions [Line Items]
Commodity sales	0	0
Services	0	0
Total revenues	0	0
Cost of sales and fuel (exclusive of items shown separately below)	0	0
Operating expenses	0	0
(Gain) loss on sale of assets	0	0
Operating income	0	0
Equity in net earnings from investments	253,500	145,600
Other income (expense), net	94,400	86,800
Interest expense, net	(94,400)	(86,800)
Income before income taxes	253,500	145,600
Income taxes	0	0
Net income	253,500	145,600
Less: Net income attributable to noncontrolling interests	0	0
Net income attributable to ONEOK Partners, L.P.	253,500	145,600
Guarantor Subsidiary [member]
Condensed Financial Statements, Captions [Line Items]
Commodity sales	0	0
Services	0	0
Total revenues	0	0
Cost of sales and fuel (exclusive of items shown separately below)	0	0
Operating expenses	0	0
(Gain) loss on sale of assets	0	0
Operating income	0	0
Equity in net earnings from investments	253,500	145,600
Other income (expense), net	94,400	86,800
Interest expense, net	(94,400)	(86,800)
Income before income taxes	253,500	145,600
Income taxes	0	0
Net income	253,500	145,600
Less: Net income attributable to noncontrolling interests	0	0
Net income attributable to ONEOK Partners, L.P.	253,500	145,600
Combined Non-Guarantor Subsidiaries [member]
Condensed Financial Statements, Captions [Line Items]
Commodity sales	1,283,500	1,435,700
Services	490,400	369,100
Total revenues	1,773,900	1,804,800
Cost of sales and fuel (exclusive of items shown separately below)	1,195,700	1,343,900
Operating expenses	264,100	264,000
(Gain) loss on sale of assets	4,100	0
Operating income	318,200	196,900
Equity in net earnings from investments	14,200	11,300
Other income (expense), net	(200)	2,700
Interest expense, net	(92,600)	(80,700)
Income before income taxes	239,600	130,200
Income taxes	(2,000)	(2,800)
Net income	237,600	127,400
Less: Net income attributable to noncontrolling interests	2,800	1,400
Net income attributable to ONEOK Partners, L.P.	234,800	126,000
Consolidating Entries [member]
Condensed Financial Statements, Captions [Line Items]
Commodity sales	0	0
Services	0	0
Total revenues	0	0
Cost of sales and fuel (exclusive of items shown separately below)	0	0
Operating expenses	0	0
(Gain) loss on sale of assets	0	0
Operating income	0	0
Equity in net earnings from investments	(488,300)	(271,600)
Other income (expense), net	(188,800)	(173,600)
Interest expense, net	188,800	173,600
Income before income taxes	(488,300)	(271,600)
Income taxes	0	0
Net income	(488,300)	(271,600)
Less: Net income attributable to noncontrolling interests	0	0
Net income attributable to ONEOK Partners, L.P.	(488,300)	(271,600)
Total [Member]
Condensed Financial Statements, Captions [Line Items]
Commodity sales	1,283,500	1,435,700
Services	490,400	369,100
Total revenues	1,773,900	1,804,800
Cost of sales and fuel (exclusive of items shown separately below)	1,195,700	1,343,900
Operating expenses	264,100	264,000
(Gain) loss on sale of assets	4,100	0
Operating income	318,200	196,900
Equity in net earnings from investments	32,900	30,900
Other income (expense), net	(200)	2,700
Interest expense, net	(92,600)	(80,700)
Income before income taxes	258,300	149,800
Income taxes	(2,000)	(2,800)
Net income	256,300	147,000
Less: Net income attributable to noncontrolling interests	2,800	1,400
Net income attributable to ONEOK Partners, L.P.	$ 253,500	145,600
Northern Border Pipeline [Member]
Condensed Financial Statements, Captions [Line Items]
Equity Method Investment, Ownership Percentage	50.00%
Equity in net earnings from investments	$ 18,674	$ 19,702

SUPPLEMENTAL CONDENSED CONSOL52

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION, Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
Condensed Financial Statements, Captions [Line Items]
Net income	$ 256,286	$ 147,032
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives	(19,933)	(12,557)
Realized (gains) losses on derivatives recognized in net income	(10,680)	(11,333)
Other comprehensive income (loss) on investment in unconsolidated affiliates	(5,801)	0
Total other comprehensive income (loss)	(36,414)	(23,890)
Comprehensive income	219,872	123,142
Less: Comprehensive income attributable to noncontrolling interests	2,769	1,438
Comprehensive income attributable to ONEOK Partners, L.P.	217,103	121,704
Parent [member]
Condensed Financial Statements, Captions [Line Items]
Net income	253,500	145,600
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives	(19,900)	(12,600)
Realized (gains) losses on derivatives recognized in net income	(10,700)	(11,300)
Other comprehensive income (loss) on investment in unconsolidated affiliates	(5,800)
Total other comprehensive income (loss)	(36,400)	(23,900)
Comprehensive income	217,100	121,700
Less: Comprehensive income attributable to noncontrolling interests	0	0
Comprehensive income attributable to ONEOK Partners, L.P.	217,100	121,700
Guarantor Subsidiary [member]
Condensed Financial Statements, Captions [Line Items]
Net income	253,500	145,600
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives	11,700	10,000
Realized (gains) losses on derivatives recognized in net income	(14,500)	(14,200)
Other comprehensive income (loss) on investment in unconsolidated affiliates	(5,800)
Total other comprehensive income (loss)	(8,600)	(4,200)
Comprehensive income	244,900	141,400
Less: Comprehensive income attributable to noncontrolling interests	0	0
Comprehensive income attributable to ONEOK Partners, L.P.	244,900	141,400
Combined Non-Guarantor Subsidiaries [member]
Condensed Financial Statements, Captions [Line Items]
Net income	237,600	127,400
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives	11,700	10,000
Realized (gains) losses on derivatives recognized in net income	(14,500)	(14,200)
Other comprehensive income (loss) on investment in unconsolidated affiliates	(5,800)
Total other comprehensive income (loss)	(8,600)	(4,200)
Comprehensive income	229,000	123,200
Less: Comprehensive income attributable to noncontrolling interests	2,800	1,400
Comprehensive income attributable to ONEOK Partners, L.P.	226,200	121,800
Consolidating Entries [member]
Condensed Financial Statements, Captions [Line Items]
Net income	(488,300)	(271,600)
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives	(23,400)	(20,000)
Realized (gains) losses on derivatives recognized in net income	29,000	28,400
Other comprehensive income (loss) on investment in unconsolidated affiliates	11,600
Total other comprehensive income (loss)	17,200	8,400
Comprehensive income	(471,100)	(263,200)
Less: Comprehensive income attributable to noncontrolling interests	0	0
Comprehensive income attributable to ONEOK Partners, L.P.	(471,100)	(263,200)
Total [Member]
Condensed Financial Statements, Captions [Line Items]
Net income	256,300	147,000
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives	(19,900)	(12,600)
Realized (gains) losses on derivatives recognized in net income	(10,700)	(11,300)
Other comprehensive income (loss) on investment in unconsolidated affiliates	(5,800)
Total other comprehensive income (loss)	(36,400)	(23,900)
Comprehensive income	219,900	123,100
Less: Comprehensive income attributable to noncontrolling interests	2,800	1,400
Comprehensive income attributable to ONEOK Partners, L.P.	$ 217,100	$ 121,700

SUPPLEMENTAL CONDENSED CONSOL53

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION, Balance Sheet (Details) - USD ($) $ in Thousands	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015	Dec. 31, 2014
Current assets
Cash and cash equivalents	$ 9,882	$ 5,079	$ 90,531	$ 42,530
Accounts receivable, net	520,800	593,448
Affiliate receivables	3,563	7,969
Natural gas and natural gas liquids in storage	156,075	128,084
Other current assets	44,256	33,207
Total current assets	856,462	883,164
Property, plant and equipment
Property, plant and equipment	14,448,918	14,307,546
Accumulated depreciation and amortization	2,126,432	2,050,755
Net property, plant and equipment	12,322,486	12,256,791
Investments and other assets
Other assets	14,663	14,533
Total investments and other assets	1,765,774	1,787,631
Total assets	14,944,722	14,927,586	14,807,515
Current liabilities
Current maturities of long-term debt	457,650	107,650
Short-term borrowings	444,567	546,340
Accounts payable	513,453	605,431
Affiliate payables	20,070	27,137
Other current liabilities	109,341	116,667
Total current liabilities	1,709,288	1,580,300
Long-term debt, excluding current maturities	6,692,238	6,695,312
Deferred credits and other liabilities	$ 165,522	$ 154,631
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	$ 6,217,320	$ 6,333,218
Noncontrolling interests in consolidated subsidiaries	160,354	164,125	167,129
Total equity	6,377,674	6,497,343
Total liabilities and equity	14,944,722	14,927,586
Parent [member]
Current assets
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Affiliate receivables	0	0
Natural gas and natural gas liquids in storage	0	0
Other current assets	400	4,100
Total current assets	400	4,100
Property, plant and equipment
Property, plant and equipment	0	0
Accumulated depreciation and amortization	0	0
Net property, plant and equipment	0	0
Investments and other assets
Intercompany notes receivable	10,383,800	10,144,900
Other assets	3,505,900	3,594,000
Total investments and other assets	13,889,700	13,738,900
Total assets	13,890,100	13,743,000
Current liabilities
Current maturities of long-term debt	450,000	100,000
Short-term borrowings	444,600	546,300
Accounts payable	0	0
Affiliate payables	0	0
Other current liabilities	121,700	112,500
Total current liabilities	1,016,300	758,800
Intercompany Debt	0	0
Long-term debt, excluding current maturities	6,649,900	6,651,000
Deferred credits and other liabilities	$ 6,600	$ 0
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	$ 6,217,300	$ 6,333,200
Noncontrolling interests in consolidated subsidiaries	0	0
Total equity	6,217,300	6,333,200
Total liabilities and equity	13,890,100	13,743,000
Guarantor Subsidiary [member]
Current assets
Cash and cash equivalents	9,900	5,100	90,500	42,500
Accounts receivable, net	0	0
Affiliate receivables	0	0
Natural gas and natural gas liquids in storage	0	0
Other current assets	0	0
Total current assets	9,900	5,100
Property, plant and equipment
Property, plant and equipment	0	0
Accumulated depreciation and amortization	0	0
Net property, plant and equipment	0	0
Investments and other assets
Intercompany notes receivable	7,704,400	7,781,800
Other assets	6,175,400	5,952,000
Total investments and other assets	13,879,800	13,733,800
Total assets	13,889,700	13,738,900
Current liabilities
Current maturities of long-term debt	0	0
Short-term borrowings	0	0
Accounts payable	0	0
Affiliate payables	0	0
Other current liabilities	0	0
Total current liabilities	0	0
Intercompany Debt	10,383,800	10,144,900
Long-term debt, excluding current maturities	0	0
Deferred credits and other liabilities	$ 0	$ 0
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	$ 3,505,900	$ 3,594,000
Noncontrolling interests in consolidated subsidiaries	0	0
Total equity	3,505,900	3,594,000
Total liabilities and equity	13,889,700	13,738,900
Combined Non-Guarantor Subsidiaries [member]
Current assets
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	520,800	593,400
Affiliate receivables	3,600	8,000
Natural gas and natural gas liquids in storage	156,100	128,100
Other current assets	165,700	144,500
Total current assets	846,200	874,000
Property, plant and equipment
Property, plant and equipment	14,448,900	14,307,500
Accumulated depreciation and amortization	2,126,400	2,050,700
Net property, plant and equipment	12,322,500	12,256,800
Investments and other assets
Intercompany notes receivable	0	0
Other assets	1,406,400	1,425,200
Total investments and other assets	1,406,400	1,425,200
Total assets	14,575,100	14,556,000
Current liabilities
Current maturities of long-term debt	7,700	7,700
Short-term borrowings	0	0
Accounts payable	513,500	605,400
Affiliate payables	20,100	27,100
Other current liabilities	151,700	181,400
Total current liabilities	693,000	821,600
Intercompany Debt	7,704,400	7,781,800
Long-term debt, excluding current maturities	42,300	44,300
Deferred credits and other liabilities	$ 158,900	$ 154,600
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	$ 5,816,100	$ 5,589,600
Noncontrolling interests in consolidated subsidiaries	160,400	164,100
Total equity	5,976,500	5,753,700
Total liabilities and equity	14,575,100	14,556,000
Consolidating Entries [member]
Current assets
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Affiliate receivables	0	0
Natural gas and natural gas liquids in storage	0	0
Other current assets	0	0
Total current assets	0	0
Property, plant and equipment
Property, plant and equipment	0	0
Accumulated depreciation and amortization	0	0
Net property, plant and equipment	0	0
Investments and other assets
Intercompany notes receivable	(18,088,200)	(17,926,700)
Other assets	(9,322,000)	(9,183,600)
Total investments and other assets	(27,410,200)	(27,110,300)
Total assets	(27,410,200)	(27,110,300)
Current liabilities
Current maturities of long-term debt	0	0
Short-term borrowings	0	0
Accounts payable	0	0
Affiliate payables	0	0
Other current liabilities	0	0
Total current liabilities	0	0
Intercompany Debt	(18,088,200)	(17,926,700)
Long-term debt, excluding current maturities	0	0
Deferred credits and other liabilities	$ 0	$ 0
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	$ (9,322,000)	$ (9,183,600)
Noncontrolling interests in consolidated subsidiaries	0	0
Total equity	(9,322,000)	(9,183,600)
Total liabilities and equity	(27,410,200)	(27,110,300)
Total [Member]
Current assets
Cash and cash equivalents	9,900	5,100	$ 90,500	$ 42,500
Accounts receivable, net	520,800	593,400
Affiliate receivables	3,600	8,000
Natural gas and natural gas liquids in storage	156,100	128,100
Other current assets	166,100	148,600
Total current assets	856,500	883,200
Property, plant and equipment
Property, plant and equipment	14,448,900	14,307,500
Accumulated depreciation and amortization	2,126,400	2,050,700
Net property, plant and equipment	12,322,500	12,256,800
Investments and other assets
Intercompany notes receivable	0	0
Other assets	1,765,700	1,787,600
Total investments and other assets	1,765,700	1,787,600
Total assets	14,944,700	14,927,600
Current liabilities
Current maturities of long-term debt	457,700	107,700
Short-term borrowings	444,600	546,300
Accounts payable	513,500	605,400
Affiliate payables	20,100	27,100
Other current liabilities	273,400	293,900
Total current liabilities	1,709,300	1,580,400
Intercompany Debt	0	0
Long-term debt, excluding current maturities	6,692,200	6,695,300
Deferred credits and other liabilities	$ 165,500	$ 154,600
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	$ 6,217,300	$ 6,333,200
Noncontrolling interests in consolidated subsidiaries	160,400	164,100
Total equity	6,377,700	6,497,300
Total liabilities and equity	$ 14,944,700	$ 14,927,600

SUPPLEMENTAL CONDENSED CONSOL54

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION, Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Operating activities
Cash provided by operating activities	$ 266,253	$ 65,117
Investing activities
Capital expenditures	(195,896)	(343,036)
Cash provided by (used in) investing activities	(169,493)	(332,964)
Financing activities
Cash distributions paid to general and limited partners	(333,001)	(295,706)
Cash distributions paid to noncontrolling interests	(2,500)	(2,246)
Borrowing (repayment) of short-term borrowings, net	(101,773)	(229,821)
Issuance of long-term debt, net of discounts	1,000,000	798,896
Debt financing costs	(2,770)	(7,850)
Repayment of long-term debt	(651,913)	(1,913)
Issuance of common units, net of issuance costs	0	53,388
Contribution from general partner	0	1,100
Cash provided by (used in) financing activities	(91,957)	315,848
Change in cash and cash equivalents	4,803	48,001
Cash and cash equivalents at beginning of period	5,079	42,530	$ 42,530
Cash and cash equivalents at end of period	9,882	90,531	5,079
Parent [member]
Operating activities
Cash provided by operating activities	318,800	218,800
Investing activities
Capital expenditures	0	0
Other investing activities	0	0
Cash provided by (used in) investing activities	0	0
Financing activities
Cash distributions paid to general and limited partners	(333,000)	(295,700)
Cash distributions paid to noncontrolling interests	0	0
Intercompany borrowings (advances), net	(231,200)	(538,800)
Borrowing (repayment) of short-term borrowings, net		(229,800)
Borrowing (repayment) of short-term borrowings, net	(101,800)
Issuance of long-term debt, net of discounts	1,000,000	798,900
Debt financing costs	(2,800)	(7,900)
Repayment of long-term debt	(650,000)	0
Issuance of common units, net of issuance costs		53,400
Contribution from general partner		1,100
Cash provided by (used in) financing activities	(318,800)	(218,800)
Change in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	0	0	0
Guarantor Subsidiary [member]
Operating activities
Cash provided by operating activities	18,700	19,700
Investing activities
Capital expenditures	0	0
Other investing activities	3,200	1,700
Cash provided by (used in) investing activities	3,200	1,700
Financing activities
Cash distributions paid to general and limited partners	(333,000)	(295,700)
Cash distributions paid to noncontrolling interests	0	0
Intercompany borrowings (advances), net	315,900	322,300
Borrowing (repayment) of short-term borrowings, net		0
Borrowing (repayment) of short-term borrowings, net	0
Issuance of long-term debt, net of discounts	0	0
Debt financing costs	0	0
Repayment of long-term debt	0	0
Issuance of common units, net of issuance costs		0
Contribution from general partner		0
Cash provided by (used in) financing activities	(17,100)	26,600
Change in cash and cash equivalents	4,800	48,000
Cash and cash equivalents at beginning of period	5,100	42,500	42,500
Cash and cash equivalents at end of period	9,900	90,500	5,100
Combined Non-Guarantor Subsidiaries [member]
Operating activities
Cash provided by operating activities	261,800	122,300
Investing activities
Capital expenditures	(195,900)	(343,000)
Other investing activities	23,200	8,300
Cash provided by (used in) investing activities	(172,700)	(334,700)
Financing activities
Cash distributions paid to general and limited partners	0	0
Cash distributions paid to noncontrolling interests	(2,500)	(2,200)
Intercompany borrowings (advances), net	(84,700)	216,500
Borrowing (repayment) of short-term borrowings, net		0
Borrowing (repayment) of short-term borrowings, net	0
Issuance of long-term debt, net of discounts	0	0
Debt financing costs	0	0
Repayment of long-term debt	(1,900)	(1,900)
Issuance of common units, net of issuance costs		0
Contribution from general partner		0
Cash provided by (used in) financing activities	(89,100)	212,400
Change in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	0	0	0
Consolidating Entries [member]
Operating activities
Cash provided by operating activities	(333,000)	(295,700)
Investing activities
Capital expenditures	0	0
Other investing activities	0	0
Cash provided by (used in) investing activities	0	0
Financing activities
Cash distributions paid to general and limited partners	333,000	295,700
Cash distributions paid to noncontrolling interests	0	0
Intercompany borrowings (advances), net	0	0
Borrowing (repayment) of short-term borrowings, net		0
Borrowing (repayment) of short-term borrowings, net	0
Issuance of long-term debt, net of discounts	0	0
Debt financing costs	0	0
Repayment of long-term debt	0	0
Issuance of common units, net of issuance costs		0
Contribution from general partner		0
Cash provided by (used in) financing activities	333,000	295,700
Change in cash and cash equivalents	0	0
Cash and cash equivalents at beginning of period	0	0	0
Cash and cash equivalents at end of period	0	0	0
Total [Member]
Operating activities
Cash provided by operating activities	266,300	65,100
Investing activities
Capital expenditures	(195,900)	(343,000)
Other investing activities	26,400	10,000
Cash provided by (used in) investing activities	(169,500)	(333,000)
Financing activities
Cash distributions paid to general and limited partners	(333,000)	(295,700)
Cash distributions paid to noncontrolling interests	(2,500)	(2,200)
Intercompany borrowings (advances), net	0	0
Borrowing (repayment) of short-term borrowings, net		(229,800)
Borrowing (repayment) of short-term borrowings, net	(101,800)
Issuance of long-term debt, net of discounts	1,000,000	798,900
Debt financing costs	(2,800)	(7,900)
Repayment of long-term debt	(651,900)	(1,900)
Issuance of common units, net of issuance costs		53,400
Contribution from general partner		1,100
Cash provided by (used in) financing activities	(92,000)	315,900
Change in cash and cash equivalents	4,800	48,000
Cash and cash equivalents at beginning of period	5,100	42,500	42,500
Cash and cash equivalents at end of period	$ 9,900	$ 90,500	$ 5,100