ONEOK Partners (OKS) 10-K 23 Feb 16 2015 FY Annual report Financial data

Document And Entity Information

Document And Entity Information - USD ($) $ in Billions	12 Months Ended
	Dec. 31, 2015	Feb. 16, 2016	Jun. 30, 2015
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
Entity Public Float			$ 5.7
Document Fiscal Year Focus	2,015
Document Fiscal Period Focus	FY
Document Type	10-K
Amendment Flag	false
Document Period End Date	Dec. 31, 2015
Common Units [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		212,837,980
Class B Units [Member]
Document Information [Line Items]
Entity Common Stock, Shares Outstanding		72,988,252

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Revenues [Abstract]
Commodity sales	$ 6,098,343	$ 10,724,981	$ 10,549,157
Services	1,662,725	1,466,684	1,320,116
Total revenues	7,761,068	12,191,665	11,869,273
Cost of sales and fuel (exclusive of items shown separately below)	5,641,052	10,088,548	10,222,213
Operations and maintenance	609,123	599,076	464,633
Depreciation and amortization	352,196	291,236	236,743
Impairment of long-lived assets (Note E)	83,673	0	0
General taxes	83,053	70,581	56,880
Gain (loss) on sale of assets	6,108	6,599	11,881
Operating income	998,079	1,148,823	900,685
Equity in net earnings from investments (Note M)	125,300	117,415	110,517
Impairment of equity method investments (Note M)	(180,583)	(76,412)	0
Allowance for equity funds used during construction	2,179	14,937	30,522
Other income	126	5,447	12,870
Other expense	(4,174)	(4,299)	(3,039)
Interest expense (net of capitalized interest of $36,572, $54,813 and $56,506, respectively)	(338,911)	(281,908)	(236,714)
Income before income taxes	602,016	924,003	814,841
Income taxes (Note L)	(4,144)	(12,668)	(10,858)
Net income	597,872	911,335	803,983
Less: Net income attributable to noncontrolling interests	8,330	1,037	357
Net income attributable to ONEOK Partners, L.P.	589,542	910,298	803,626
Limited partners' interest in net income:
Net income attributable to ONEOK Partners, L.P.	589,542	910,298	803,626
General partner's interest in net income	(394,550)	(344,241)	(275,539)
Limited partners' interest in net income	$ 194,992	$ 566,057	$ 528,087
Limited partners' net income per unit, basic and diluted (Note K)	$ 0.73	$ 2.33	$ 2.35
Number of units used in computation (thousands)	267,281	243,306	224,658

CONSOLIDATED STATEMENTS OF INC3

CONSOLIDATED STATEMENTS OF INCOME (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Income Statement [Abstract]
Interest Costs, Capitalized During Period	$ 36,572	$ 54,813	$ 56,506
Net Income (Loss), Net of Tax, Per Outstanding Limited Partnership Unit, Diluted	$ 0.73	$ 2.33	$ 2.35

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net income	$ 9,565	$ 229,665	$ 211,610	$ 147,032	$ 264,036	$ 167,320	$ 214,511	$ 265,468	$ 597,872	$ 911,335	$ 803,983
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives									45,575	(64,639)	32,141
Realized (gains) losses on derivatives recognized in net income									(67,034)	31,653	8,344
Total other comprehensive income (loss)									(21,459)	(32,986)	40,485
Comprehensive income									576,413	878,349	844,468
Less: Comprehensive income attributable to noncontrolling interests									8,330	1,037	357
Comprehensive income attributable to ONEOK Partners, L.P.									$ 568,083	$ 877,312	$ 844,111

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Current assets
Cash and cash equivalents	$ 5,079	$ 42,530
Accounts receivable, net	593,448	735,830
Affiliate receivables	7,969	8,553
Natural gas and natural gas liquids in storage	128,084	134,134
Commodity imbalances	38,681	64,788
Materials and supplies	76,696	55,833
Other current assets	33,207	44,385
Total current assets	883,164	1,086,053
Property, plant and equipment
Property, plant and equipment	14,307,546	13,377,617
Accumulated depreciation and amortization	2,050,755	1,842,084
Net property, plant and equipment (Note E)	12,256,791	11,535,533
Investments and other assets
Investments in unconsolidated affiliates (Note M)	948,221	1,132,653
Goodwill and intangible assets (Note F)	824,877	822,358
Other assets	14,533	23,803
Total investments and other assets	1,787,631	1,978,814
Total assets	14,927,586	14,600,400
Current liabilities
Current maturities of long-term debt (Note H)	107,650	7,650
Short-term borrowings (Note G)	546,340	1,055,296
Accounts payable	605,431	874,692
Affiliate payables	27,137	36,106
Commodity imbalances	74,460	104,650
Accrued interest	102,615	91,990
Other current liabilities	116,667	165,672
Total current liabilities	1,580,300	2,336,056
Long-term debt, excluding current maturities (Note H)	6,695,312	6,004,232
Deferred credits and other liabilities	$ 154,631	$ 141,337
Commitments and contingencies (Note O)
ONEOK Partners, L.P. partners' equity (Note I):
General partner	$ 231,344	$ 211,914
Common units: 212,837,980 and 180,826,973 units issued and outstanding at December 31, 2015 and December 31, 2014, respectively	5,014,952	4,456,372
Class B units: 72,988,252 units issued and outstanding at December 31, 2015 and December 31, 2014	1,200,204	1,374,375
Accumulated other comprehensive loss (Note J)	(113,282)	(91,823)
Total ONEOK Partners, L.P. partners' equity	6,333,218	5,950,838
Noncontrolling interests in consolidated subsidiaries	164,125	167,937
Total equity	6,497,343	6,118,775
Total liabilities and equity	$ 14,927,586	$ 14,600,400

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - shares	Dec. 31, 2015	Dec. 31, 2014
ONEOK Partners, L.P. partners equity:
Common units issued (in shares)	212,837,980	180,826,973
Common units outstanding (in shares)	212,837,980	180,826,973
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	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities
Net income	$ 597,872	$ 911,335	$ 803,983
Adjustments to reconcile net income to net cash provided by operating activities
Depreciation and amortization	352,196	291,236	236,743
Impairment charges	264,256	76,412	0
Allowance for equity funds used during construction	(2,179)	(14,937)	(30,522)
Gain on sale of assets	(6,108)	(6,599)	(11,881)
Deferred income taxes	4,765	10,832	5,444
Equity in net earnings from investments	(125,300)	(117,415)	(110,517)
Distributions received from unconsolidated affiliates	122,003	117,912	106,364
Distributions received from unconsolidated affiliates	155,918	139,019	137,498
Changes in assets and liabilities, net of acquisitions:
Accounts receivable	147,767	373,459	(184,271)
Affiliate receivables	584	632	6,907
Natural gas and natural gas liquids in storage	6,050	54,152	47,550
Accounts payable	(199,895)	(351,470)	187,253
Affiliate payables	(8,969)	(11,352)	(28,252)
Commodity imbalances, net	(4,083)	(93,234)	(50,373)
Accrued Interest	10,625	(721)	15,977
Risk-management assets and liabilities	(34,275)	36,444	12,109
Other assets and liabilities, net	(53,329)	33,134	1,217
Cash provided by operating activities	1,071,980	1,309,820	1,007,731
Investing activities
Capital expenditures (less allowance for equity funds used during construction)	(1,186,123)	(1,745,990)	(1,939,326)
Cash paid for acquisition, net of cash received	0	(814,934)	(394,889)
Contributions to unconsolidated affiliates	(27,540)	(1,063)	(35,308)
Distributions received from unconsolidated affiliates in excess of cumulative earnings	33,915	21,107	31,134
Proceeds from sale of assets	3,825	7,817	12,290
Other	(12,607)	0	0
Cash used in investing activities	(1,188,530)	(2,533,063)	(2,326,099)
Financing activities
Cash distributions: General and limited partners	1,230,475	1,052,245	909,713
Cash distributions: Noncontrolling interests	(11,690)	(549)	(588)
Issuance of long-term debt, net of discounts	798,896	0	1,247,822
Debt financing costs	(7,676)	0	(10,246)
Repayment of long-term debt	(7,650)	(7,650)	(7,650)
Issuance of common units, net of issuance costs	1,025,660	1,113,139	583,929
Contribution from general partner	20,990	23,252	12,270
Cash provided by financing activities	79,099	1,131,243	915,824
Change in cash and cash equivalents	(37,451)	(92,000)	(402,544)
Cash and cash equivalents at beginning of period	42,530	134,530	537,074
Cash and cash equivalents at end of period	5,079	42,530	134,530
Supplemental cash flow information:
Cash paid for interest, net of amounts capitalized	307,036	271,314	203,072
Cash paid for income taxes	3,483	1,336	3,435
Proceeds from (Repayments of) Short-term Debt	$ (508,956)	$ 1,055,296	$ 0

CONSOLIDATED STATEMENT OF CHANG

CONSOLIDATED STATEMENT OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Noncontrolling Interests in Consolidated Subsidiaries [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	General Partner [Member]	Class B Units [Member]	Common Units [Member]
Partners capital account, units, beginning balance at Dec. 31, 2012					72,988,252	146,827,354
Partners capital account beginning balance at Dec. 31, 2012	$ 4,463,507	$ 4,767	$ (99,322)	$ 152,513	$ 1,460,498	$ 2,945,051
Net income	803,983	357	0	275,539	171,494	356,593
Other comprehensive income (loss)	40,485	0	40,485	0	$ 0	$ 0
Issuance of common units (in units) (Note I)					0	12,180,500
Issuance of common units (Note I)	588,656	0	0	0	$ 0	$ 588,656
Contribution from general partner (Note I)	12,366	0	0	12,366	0	0
Distributions paid (Note I)	(910,301)	(588)	0	(269,857)	$ (209,476)	$ (430,380)
Partners capital account, units, ending balance at Dec. 31, 2013					72,988,252	159,007,854
Partners capital account ending balance at Dec. 31, 2013	4,998,696	4,536	(58,837)	170,561	$ 1,422,516	$ 3,459,920
Net income	911,335	1,037	0	344,241	171,554	394,503
Other comprehensive income (loss)	(32,986)	0	(32,986)	0	$ 0	$ 0
Issuance of common units (in units) (Note I)					0	21,819,119
Issuance of common units (Note I)	1,108,456	0	0	0	$ 0	$ 1,108,456
Contribution from general partner (Note I)	23,155	0	0	23,155	0	0
Distributions paid (Note I)	(1,052,794)	(549)	0	(326,043)	(219,695)	(506,507)
West Texas LPG noncontrolling interest (Note B)	162,913	162,913	0	0	$ 0	$ 0
Partners capital account, units, ending balance at Dec. 31, 2014					72,988,252	180,826,973
Partners capital account ending balance at Dec. 31, 2014	6,118,775	167,937	(91,823)	211,914	$ 1,374,375	$ 4,456,372
Net income	597,872	8,330	0	394,550	56,472	138,520
Other comprehensive income (loss)	(21,459)	0	(21,459)	0	$ 0	$ 0
Issuance of common units (in units) (Note I)					0	32,011,007
Issuance of common units (Note I)	1,023,767	0	0	0	$ 0	$ 1,023,767
Contribution from general partner (Note I)	20,990	0	0	20,990	0	0
Distributions paid (Note I)	(1,242,165)	(11,690)	0	(396,110)	(230,643)	(603,722)
Other	(437)	(452)	0	0	$ 0	$ 15
Partners capital account, units, ending balance at Dec. 31, 2015					72,988,252	212,837,980
Partners capital account ending balance at Dec. 31, 2015	$ 6,497,343	$ 164,125	$ (113,282)	$ 231,344	$ 1,200,204	$ 5,014,952

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	12 Months Ended
	Dec. 31, 2015
Accounting Policies [Abstract]
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES	A . SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Organization and Nature of Operations - ONEOK Partners, L.P. is a publicly traded master limited partnership, organized under the laws of the state of Delaware, that was formed in 1993. Our equity consists of a 2 percent general partner interest and a 98 percent limited partner interest. Our limited partner interests are represented by our common units, which are listed on the NYSE under the trading symbol “OKS,” and our Class B limited partner units. We are managed under the direction of the Board of Directors of our sole general partner, ONEOK Partners GP. ONEOK Partners GP is a wholly owned subsidiary of ONEOK. ONEOK and its subsidiaries owned a 41.2 percent aggregate equity interest in us at December 31, 2015. Our operations include gathering and processing of natural gas produced from crude oil and natural gas wells. We gather and process natural gas in the Mid-Continent region, which includes the NGL-rich Cana-Woodford Shale, Woodford Shale, Springer Shale, Stack, SCOOP areas of Oklahoma, the Mississippian Lime formation of Oklahoma and Kansas, and the Hugoton and Central Kansas Uplift Basins of Kansas. We also gather and/or process natural gas in two producing basins in the Rocky Mountain region: the Williston Basin, which spans portions of Montana and North Dakota and includes the oil-producing, NGL-rich Bakken Shale and Three Forks formations; and the Powder River Basin of Wyoming, which includes the NGL-rich Frontier, Turner, Sussex and Niobrara Shale formations. The natural gas we gather from wells that supply our Sage Creek plant contains NGL-rich natural gas from the Niobrara Shale area of the Powder River Basin. Our natural gas liquids assets consist of facilities that gather, fractionate and treat NGLs and store NGL products primarily in Oklahoma, Kansas, Texas, New Mexico and the Rocky Mountain region where we provide nondiscretionary services to producers of NGLs. We own or have an ownership interest in FERC-regulated natural gas liquids gathering and distribution pipelines in Oklahoma, Kansas, Texas, New Mexico, Montana, North Dakota, Wyoming and Colorado, and terminal and storage facilities in Missouri, Nebraska, Iowa and Illinois. We also own FERC-regulated natural gas liquids distribution and refined petroleum products pipelines in Kansas, Missouri, Nebraska, Iowa, Illinois and Indiana that connect our Mid-Continent assets with Midwest markets, including Chicago, Illinois. We own and operate truck- and rail-loading and -unloading facilities that interconnect with our NGL fractionation and pipeline assets. Our Natural Gas Pipeline segment operates interstate and intrastate natural gas transmission pipelines and natural gas storage facilities. Our FERC-regulated interstate natural gas pipeline assets transport natural gas through pipelines in North Dakota, Minnesota, Wisconsin, Illinois, Indiana, Kentucky, Tennessee, Oklahoma, Texas and New Mexico. Our intrastate natural gas pipeline assets in Oklahoma transport natural gas throughout the state and have access to the major natural gas producing formations, including the Cana-Woodford Shale, Woodford Shale, Springer Shale, Granite Wash, Stack, SCOOP and Mississippian Lime areas. During 2015, we entered into a 50-50 joint venture, Roadrunner, which will transport natural gas from the Permian Basin in West Texas to the Mexican border near El Paso, Texas. The Roadrunner pipeline is currently under construction, with Phase I expected to be completed in the first quarter 2016. We own underground natural gas storage facilities in Oklahoma and Texas that are connected to our intrastate natural gas pipeline assets. We also have underground natural gas storage facilities in Kansas. Consolidation - Our consolidated financial statements include the accounts of ONEOK Partners and our subsidiaries over which we have control or are the primary beneficiary. All significant intercompany balances and transactions have been eliminated in consolidation. Investments in unconsolidated affiliates are accounted for using the equity method if we have the ability to exercise significant influence over operating and financial policies of our investee. Under this method, an investment is carried at its acquisition cost and adjusted each period for contributions made, distributions received and our share of the investee’s comprehensive income. For the investments we account for under the equity method, the premium or excess cost over underlying fair value of net assets is referred to as equity-method goodwill. Impairment of equity investments is recorded when the impairments are other than temporary. These amounts are recorded as investments in unconsolidated affiliates on our accompanying Consolidated Balance Sheets. See Note M for disclosures of our unconsolidated affiliates. Distributions paid to us from our unconsolidated affiliates are classified as operating activities on our Consolidated Statements of Cash Flows until the cumulative distributions exceed our proportionate share of income from the unconsolidated affiliate since the date of our initial investment. The amount of cumulative distributions paid to us that exceeds our cumulative proportionate share of income in each period represents a return of investment and is classified as an investing activity on our Consolidated Statements of Cash Flows. Use of Estimates - The preparation of our consolidated financial statements and related disclosures in accordance with GAAP requires us to make estimates and assumptions with respect to values or conditions that cannot be known with certainty that affect the reported amount of assets and liabilities, and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements. These estimates and assumptions also affect the reported amounts of revenue and expenses during the reporting period. Items that may be estimated include, but are not limited to, the economic useful life of assets, fair value of assets, liabilities and equity-method investments, provisions for uncollectible accounts receivable, unbilled revenues and cost of goods sold, expenses for services received but for which no invoice has been received, the results of litigation and various other recorded or disclosed amounts. We evaluate these estimates on an ongoing basis using historical experience, consultation with experts and other methods we consider reasonable based on the particular circumstances. Nevertheless, actual results may differ significantly from the estimates. Any effects on our financial position or results of operations from revisions to these estimates are recorded in the period when the facts that give rise to the revision become known. Fair Value Measurements - We define fair value as the price that would be received from the sale of an asset or the transfer of a liability in an orderly transaction between market participants at the measurement date. We use 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 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. See Note C for discussion of our fair value measurements. Cash and Cash Equivalents - Cash equivalents consist of highly liquid investments, which are readily convertible into cash and have original maturities of three months or less. Revenue Recognition - Our reportable segments recognize revenue when services are rendered or product is delivered. Our Natural Gas Gathering and Processing segment records revenues when natural gas is processed in or transported through our facilities. Our Natural Gas Liquids segment records revenues based upon contracted services and actual volumes exchanged or stored under service agreements in the period services are provided. A portion of our revenues for our Natural Gas Pipelines segment and our Natural Gas Liquids segment are recognized based upon contracted capacity and contracted volumes transported and stored under service agreements in the period services are provided. We disaggregate revenue on the Consolidated Statements of Income as follows: • Commodity sales - Commodity sales represent the sale of NGLs, condensate and residue natural gas. The commodities are primarily obtained as compensation for or related to providing services. Commodity sales are recognized upon delivery or title transfer to the customer, when revenue recognition criteria are met. • Service revenue - Service revenue represents the fees generated from the performance of our services listed above. We enter into a variety of contract types that provide commodity sales and service revenue. We provide services primarily under the following types of contracts: • Fee based - Under fee-based arrangements, we receive a fee or fees for one or more of the following services: gathering, compression, processing, transmission and storage of natural gas; and gathering, transportation, fractionation, exchange and storage of NGLs. The revenue we earn from these arrangements generally is directly related to the volume of natural gas and NGLs that flow through our systems and facilities, and is not normally directly dependent on commodity prices. However, to the extent a sustained decline in commodity prices results in a decline in volumes, our revenues from these arrangements would be reduced. In addition, many of our arrangements provide for fixed fee, minimum volume or firm demand charges. Fee-based arrangements are reported as service revenue on the Consolidated Statements of Income. • Percent-of-proceeds - Under POP arrangements in our Natural Gas Gathering and Processing segment, we gather and process natural gas on behalf of producers; sell the resulting residue natural gas, condensate and NGLs at market prices; and remit to producers an agreed-upon percentage of the net proceeds resulting from the sale. The agreed-upon percentage remitted to the producer is reported as cost of sales on the Consolidated Statements of Income. In other cases, instead of remitting cash payments to the producer, we deliver an agreed-upon percentage of the commodities to the producer (take-in-kind agreements) and sell the volumes we retain to third parties. Typically, our POP arrangements also include a fee-based component. In many cases, we provide services under contracts that contain a combination of the arrangements described above. When fees are charged (in addition to commodities received) under POP with fee contracts, we record such fees as service revenue on the Consolidated Statements of Income. The terms of our contracts vary based on natural gas quality conditions, the competitive environment when the contracts are signed and customer requirements. Cost of Sales and Fuel - Cost of sales and fuel primarily includes (i) the cost of purchased commodities, including NGLs, natural gas and condensate, (ii) fees incurred for third-party transportation, fractionation and storage of commodities, and (iii) fuel and power costs incurred to operate our own facilities that gather, process, transport and store commodities. Operations and Maintenance - Operations and maintenance primarily includes (i) payroll and benefit costs, (ii) third-party costs for operations, maintenance and integrity management, regulatory compliance and environmental and safety, and (iii) other business related service costs. Accounts Receivable - Accounts receivable represent valid claims against nonaffiliated customers for products sold or services rendered, net of allowances for doubtful accounts. We assess the creditworthiness of our counterparties on an ongoing basis and require security, including prepayments and other forms of collateral, when appropriate. Outstanding customer receivables are reviewed regularly for possible nonpayment indicators, and allowances for doubtful accounts are recorded based upon management’s estimate of collectability at each balance sheet date. At December 31, 2015 and 2014 , our allowance for doubtful accounts was not material. Inventory - The values of current natural gas and NGLs in storage are determined using the lower of weighted-average cost or market method. Noncurrent natural gas and NGLs are classified as property and valued at cost. Materials and supplies are valued at average cost. Commodity Imbalances - Commodity imbalances represent amounts payable or receivable for NGL exchange contracts and natural gas pipeline imbalances and are valued at market prices. Under the majority of our NGL exchange agreements, we physically receive volumes of unfractionated NGLs, including the risk of loss and legal title to such volumes, from the exchange counterparty. In turn, we deliver NGL products back to the customer and charge them gathering and fractionation fees. To the extent that the volumes we receive under such agreements differ from those we deliver, we record a net exchange receivable or payable position with the counterparties. These net exchange receivables and payables are settled with movements of NGL products rather than with cash. Natural gas pipeline imbalances are settled in cash or in-kind, subject to the terms of the pipelines’ tariffs or by agreement. Derivatives and Risk Management - We utilize derivatives to reduce our market-risk exposure to commodity price and interest-rate fluctuations and to achieve more predictable cash flows. 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. See Notes C and D for more discussion of our fair value measurements and risk-management and hedging activities using derivatives. Property, Plant and Equipment - Our properties are stated at cost, including AFUDC. Generally, the cost of regulated property retired or sold, plus removal costs, less salvage, is charged to accumulated depreciation. Gains and losses from sales or transfers of nonregulated properties or an entire operating unit or system of our regulated properties are recognized in income. Maintenance and repairs are charged directly to expense. The interest portion of AFUDC represents the cost of borrowed funds used to finance construction activities. We capitalize interest costs during the construction or upgrade of qualifying assets. Capitalized interest is recorded as a reduction to interest expense. The equity portion of AFUDC represents the capitalization of the estimated average cost of equity used during the construction of major projects and is recorded in the cost of our regulated properties and as a credit to the allowance for equity funds used during construction. Our properties are depreciated using the straight-line method over their estimated useful lives. Generally, we apply composite depreciation rates to functional groups of property having similar economic circumstances. We periodically conduct depreciation studies to assess the economic lives of our assets. For our regulated assets, these depreciation studies are completed as a part of our rate proceedings or tariff filings, and the changes in economic lives, if applicable, are implemented prospectively when the new rates are billed. For our nonregulated assets, if it is determined that the estimated economic life changes, the changes are made prospectively. Changes in the estimated economic lives of our property, plant and equipment could have a material effect on our financial position or results of operations. Property, plant and equipment on our Consolidated Balance Sheets includes construction work in process for capital projects that have not yet been placed in service and therefore are not being depreciated. Assets are transferred out of construction work in process when they are substantially complete and ready for their intended use. See Note E for disclosures of our property, plant and equipment. Impairment of Goodwill and Long-Lived Assets, Including Intangible Assets - We assess our goodwill for impairment at least annually on July 1, unless events or changes in circumstances indicate an impairment may have occurred before that time. At July 1, 2015, due to the current commodity price environment, we elected to perform a quantitative assessment, or Step 1 analysis, to test our goodwill for impairment. The assessment included our commodity price assumptions, expected contractual terms, anticipated operating costs and volume estimates. Our goodwill impairment analysis performed as of July 1, 2015, did not result in an impairment charge nor did our analysis reflect any reporting units at risk. In each reporting unit, the fair value substantially exceeded the carrying value. At December 31, 2015, we performed a qualitative review given the decline in commodity prices and our common unit price since our assessment as of July 1, 2015, and determined that no event has occurred indicating that the implied fair value of each of our reporting units is less than the carrying value of its net assets. As part of our impairment test, we may first assess qualitative factors (including macroeconomic conditions, industry and market considerations, cost factors and overall financial performance) to determine whether it is more likely than not that the fair value of each of our reporting units is less than its carrying amount. If further testing is necessary or a quantitative test is elected, we perform a two-step impairment test for goodwill. In the first step, an initial assessment is made by comparing the fair value of a reporting unit with its book value, including goodwill. If the fair value is less than the book value, an impairment is indicated, and we must perform a second test to measure the amount of the impairment. In the second test, we calculate the implied fair value of the goodwill by deducting the fair value of all tangible and intangible net assets of the reporting unit from the fair value determined in step one of the assessment. If the carrying value of the goodwill exceeds the implied fair value of the goodwill, we will record an impairment charge. To estimate the fair value of our reporting units, we use two generally accepted valuation approaches, an income approach and a market approach, using assumptions consistent with a market participant’s perspective. Under the income approach, we use anticipated cash flows over a period of years plus a terminal value and discount these amounts to their present value using appropriate discount rates. Under the market approach, we apply EBITDA multiples to forecasted EBITDA. The multiples used are consistent with historical asset transactions. The forecasted cash flows are based on average forecasted cash flows for a reporting unit over a period of years. We assess our long-lived assets, including intangible assets with finite useful lives, for impairment whenever events or changes in circumstances indicate that an asset’s carrying amount may not be recoverable. An impairment is indicated if the carrying amount of a long-lived asset exceeds the sum of the undiscounted future cash flows expected to result from the use and eventual disposition of the asset. If an impairment is indicated, we record an impairment loss equal to the difference between the carrying value and the fair value of the long-lived asset. For the investments we account for under the equity method, the impairment test considers whether the fair value of the equity investment as a whole, not the underlying net assets, has declined and whether that decline is other than temporary. Therefore, we periodically reevaluate the amount at which we carry our equity-method investments to determine whether current events or circumstances warrant adjustments to our carrying value. See Notes E , F and M for our long-lived assets, goodwill and intangible assets and investments in unconsolidated affiliates disclosures. Regulation - Our intrastate natural gas transmission and natural gas liquids pipelines are subject to the rate regulation and accounting requirements of the OCC, KCC, RRC and various municipalities in Texas. Our interstate natural gas and natural gas liquids pipelines are subject to regulation by the FERC. In Kansas and Texas, natural gas storage may be regulated by the state and the FERC for certain types of services. Accordingly, portions of our Natural Gas Liquids and Natural Gas Pipelines segments follow the accounting and reporting guidance for regulated operations. During the rate-making process for certain of our assets, regulatory authorities set the framework for what we can charge customers for our services and establish the manner that our costs are accounted for, including allowing us to defer recognition of certain costs and permitting recovery of the amounts through rates over time as opposed to expensing such costs as incurred. Certain examples of types of regulatory guidance include costs for fuel and losses, acquisition costs, contributions in aid of construction, charges for depreciation, and gains or losses on disposition of assets. This allows us to stabilize rates over time rather than passing such costs on to the customer for immediate recovery. Actions by regulatory authorities could have an effect on the amount recovered from rate payers. Any difference in the amount recoverable and the amount deferred is recorded as income or expense at the time of the regulatory action. A write-off of regulatory assets and costs not recovered may be required if all or a portion of the regulated operations have rates that are no longer: • established by independent, third-party regulators; • designed to recover the specific entity’s costs of providing regulated services; and • set at levels that will recover our costs when considering the demand and competition for our services. At December 31, 2015 and 2014 , we recorded regulatory assets of approximately $5.8 million and $6.1 million , respectively, which are currently being recovered and are expected to be recovered from our customers. Regulatory assets are being recovered as a result of approved rate proceedings over varying time periods up to 40 years. These assets are reflected in other assets on our Consolidated Balance Sheets. Income Taxes - We are not a taxable entity for federal income tax purposes. As such, we do not directly pay federal income tax. Our taxable income or loss, which may vary substantially from the net income or loss reported in our Consolidated Statements of Income, is included in the federal income tax returns of each partner. The aggregate difference in the basis of our net assets for financial and income tax purposes cannot be readily determined, as we do not have access to all information about each partner’s tax attributes related to us. Our corporate subsidiaries are required to pay federal and state income taxes. Deferred income taxes are provided for the difference between the financial statement and income tax basis of assets and liabilities and carryforward items based on income tax laws and rates existing at the time the temporary differences are expected to reverse. Generally, the effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date of the rate change. For regulated companies, the effect on deferred tax assets and liabilities of a change in tax rates is recorded as regulatory assets and regulatory liabilities in the period that includes the enactment date, if, as a result of an action by a regulator, it is probable that the effect of the change in tax rates will be recovered from or returned to customers through future rates. We utilize a more-likely-than-not recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position that is taken or expected to be taken in a tax return. We reflect penalties and interest as part of income tax expense as they become applicable for tax provisions that do not meet the more-likely-than-not recognition threshold and measurement attribute. During 2015, 2014 and 2013 , our tax positions did not require an establishment of a material reserve. We file numerous consolidated and separate income tax returns with federal tax authorities of the United States along with the tax authorities of several states. There are no United States federal audits or statute waivers at this time. See Note L for additional discussion of income taxes. Asset Retirement Obligations - Asset retirement obligations represent legal obligations associated with the retirement of long-lived assets that result from the acquisition, construction, development and/or normal use of the asset. Certain of our natural gas gathering and processing facilities, and our natural gas liquids and pipeline facilities are subject to agreements or regulations that give rise to our asset retirement obligations for removal or other disposition costs associated with retiring the assets in place upon the discontinued use of the assets. We recognize the fair value of a liability

ACQUISITIONS ACQUISITIONS (Note

ACQUISITIONS ACQUISITIONS (Notes)	12 Months Ended
	Dec. 31, 2015
Acquisition [Abstract]
ACQUISITIONS	B . ACQUISITIONS West Texas LPG - In November 2014 , we completed the acquisition of an 80 percent interest in WTLPG and a 100 percent interest in the Mesquite Pipeline for approximately $800 million from affiliates of Chevron Corporation, and we became the operator of both pipelines. Financing to close this transaction came from available cash on hand and borrowings under our existing commercial paper program. The acquisition consists of approximately 2,600 miles of natural gas liquids gathering pipelines extending from the Permian Basin in southeastern New Mexico to East Texas and Mont Belvieu, Texas. The acquired pipelines access NGL supply from producers actively developing the Delaware, Midland and Central Basins in the Permian Basin, in addition to the Barnett Shale, East Texas and north Louisiana regions. The pipeline system increased our natural gas liquids gathering system by approximately 60 percent to nearly 7,100 miles of natural gas liquids gathering pipelines and added approximately 285,000 barrels per day of NGL capacity. These assets provide us with additional fee-based earnings and our natural gas liquids infrastructure with access to a new natural gas liquids supply basin. We accounted for the West Texas LPG acquisition as a business combination which, among other things, requires assets acquired and liabilities assumed to be measured at their acquisition-date fair values. Our Consolidated Balance Sheet as of December 31, 2015, reflects the final purchase price allocation. Adjustments to the preliminary purchase price allocation reported in Note B in the Notes to the Consolidated Financial Statements in our 2014 Annual Report were not material, and prior period financial statements have not been recast. The final purchase price allocation and assessment of the fair value of the assets acquired as of the acquisition date were as follows: ( Thousands of dollars ) Cash $ 13,839 Accounts receivable 9,132 Other current assets 3,369 Property, plant and equipment Regulated 812,716 Nonregulated 157,643 Total property, plant and equipment 970,359 Total fair value of assets acquired 996,699 Accounts payable (8,621 ) Other liabilities (10,867 ) Total fair value of liabilities acquired (19,488 ) Less: Fair value of noncontrolling interest (162,438 ) Net assets acquired 814,773 Less: Cash received (13,839 ) Net cash paid for acquisition $ 800,934 Beginning November 29, 2014, the results of operations for West Texas LPG are included in our Natural Gas Liquids segment. We consolidate WTLPG and have recorded noncontrolling interests in consolidated subsidiaries on our Consolidated Statements of Income and Consolidated Balance Sheets to recognize the portion of WTLPG that we do not own. The portion of the assets and liabilities of WTLPG acquired attributable to noncontrolling interests was accounted for as noncash activity. The fair value of the noncontrolling interest of WTLPG was estimated by applying a market approach. Revenues and earnings related to West Texas LPG have been included within the Consolidated Statements of Income since the acquisition date. Supplemental pro forma revenue and earnings reflecting this acquisition as if it had occurred as of January 1, 2013, are not materially different from the information presented in the accompanying Consolidated Statements of Income and are, therefore, not presented. The limited partnership agreement of WTLPG provides that distributions to the partners are to be made on a pro rata basis according to each partner’s ownership interest. Cash distributions to the partners are currently declared and paid by WTLPG each calendar quarter. Any changes to, or suspension of, the cash distributions from WTLPG requires the approval of a minimum of 90 percent of the ownership interest and a minimum of two general partners of WTLPG. Cash distributions are equal to 100 percent of distributable cash as defined in the limited partnership agreement of WTLPG. Sage Creek - On September 30, 2013 , we completed for $305 million the acquisition of certain natural gas gathering and processing, and natural gas liquids facilities in Converse and Campbell counties, Wyoming, in the NGL-rich Niobrara Shale area of the Powder River Basin. The Sage Creek acquisition consists primarily of a 50 MMcf/d natural gas processing facility, the Sage Creek plant, and related natural gas gathering and natural gas liquids infrastructure. Included in the acquisition were supply contracts providing for long-term acreage dedications from producers in the area, which are structured with POP and fee-based contractual terms. The acquisition is complementary to our existing natural gas liquids assets and provides additional natural gas gathering and processing and natural gas liquids gathering capacity in the region. This acquisition was accounted for as a business combination. The excess of cost over those fair values was recorded as goodwill. The purchase price and assessment of the fair value of the assets acquired were as follows: Natural Gas Gathering and Processing Natural Gas Liquids Total Property, plant and equipment ( Thousands of dollars ) Gathering pipelines and related equipment $ 41,129 $ 18,045 $ 59,174 Processing and fractionation and related equipment 50,595 — 50,595 General plant and other 120 — 120 Intangible assets 40,000 63,000 103,000 Identifiable assets acquired 131,844 81,045 212,889 Goodwill 20,000 72,000 92,000 Total purchase price $ 151,844 $ 153,045 $ 304,889 Identifiable intangible assets recognized in the Sage Creek acquisition are primarily related to natural gas gathering and processing and natural gas liquids gathering and fractionation supply contracts with acreage dedications and customer relationships. The basis for determining the value of these intangible assets is the estimated future net cash flows to be derived from acquired supply contracts and customer relationships, which are offset with appropriate charges for the use of contributory assets and discounted using a risk-adjusted discount rate. Those intangible assets are being amortized on a straight-line basis over an initial 20 -year period for our Natural Gas Gathering and Processing segment and an initial 30 -year period for our Natural Gas Liquids segment, which represents a portion of the term over which the customer contracts and relationships are expected to contribute to our cash flows. Revenues and earnings related to the Sage Creek acquisition are included within the Consolidated Statements of Income since the acquisition date. Supplemental pro forma revenue and earnings reflecting this acquisition as if it had occurred as of January 1, 2012, are not materially different from the information presented in the accompanying Consolidated Statements of Income and are, therefore, not presented. Maysville - In December 2013, we acquired the remaining 30 percent undivided interest in the Maysville, Oklahoma, natural gas processing facility for $90 million . Beginning December 1, 2013 , the results of operations for our 100 percent interest are included in our Natural Gas Gathering and Processing segment.

FAIR VALUE MEASUREMENTS

FAIR VALUE MEASUREMENTS	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	C . FAIR VALUE MEASUREMENTS Recurring Fair Value Measurements - The following tables set forth our recurring fair value measurements for the periods indicated: 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) - Our 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 had $34.4 million of cash held from various counterparties and no cash collateral posted. (b) - Included in other current assets or other current liabilities in our Consolidated Balance Sheets. December 31, 2014 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net (b) ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 42,880 $ — $ 354 $ 43,234 $ (25,979 ) $ 17,255 Physical contracts — — 9,922 9,922 — 9,922 Interest-rate contracts — 2,288 — 2,288 — 2,288 Total derivative assets $ 42,880 $ 2,288 $ 10,276 $ 55,444 $ (25,979 ) $ 29,465 Derivative liabilities Commodity contracts Financial contracts $ (169 ) $ — $ (968 ) $ (1,137 ) $ 1,137 $ — Physical contracts — — (23 ) (23 ) — (23 ) Interest-rate contracts — (44,843 ) — (44,843 ) — (44,843 ) Total derivative liabilities $ (169 ) $ (44,843 ) $ (991 ) $ (46,003 ) $ 1,137 $ (44,866 ) (a) - Our 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, 2014 , we had $24.8 million of cash held from various counterparties and no cash collateral posted. (b) - Included in other current assets, other assets or other current liabilities in our Consolidated Balance Sheets. The following table sets forth a reconciliation of our Level 3 fair value measurements for the periods indicated: Years Ended December 31, Derivative Assets (Liabilities) 2015 2014 ( Thousands of dollars ) Net assets (liabilities) at beginning of period $ 9,285 $ (782 ) Total realized/unrealized gains (losses): Included in earnings (a) 216 (927 ) Included in other comprehensive income (loss) (2,170 ) 7,260 Settlements — 3,734 Net assets (liabilities) at end of period $ 7,331 $ 9,285 (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 years ended December 31, 2015 and 2014 , gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the end of 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 years ended December 31, 2015 and 2014 , there were no transfers between levels. Other Financial Instruments - The approximate fair value of cash and cash equivalents, accounts receivable, accounts payable and 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 senior notes outstanding, including current maturities, was $6.2 billion and $6.4 billion at December 31, 2015 and 2014 , respectively. The book value of the aggregate of our senior notes outstanding, including current maturities, was $6.8 billion and $6.0 billion at December 31, 2015 and 2014 , 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. During 2015 and 2014, we recorded noncash impairment charges primarily related to our equity investments in the dry natural gas area of the Powder River Basin. The valuation of these investments required use of significant unobservable inputs. We used an income approach to estimate the fair value of our investments. Our discounted cash flow analysis included the following inputs that are not readily available: a discount rate reflective of our cost of capital and estimated contract rates, volumes, operating and maintenance costs and capital expenditures. The estimated fair value of these investments is classified as Level 3. See Note M for additional information about our equity investments and the impairment charges.

RISK MANAGEMENT AND HEDGING ACT

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES	D . RISK-MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES Risk-Management Activities - 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 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; and • Swaps - Exchange of one or more payments based on the value of one or more commodities. These instruments transfer the financial risk associated with a future change in value between the counterparties of the transaction, without also conveying ownership interest in the asset or liability. We may also use other instruments including options or collars to mitigate commodity price risk. Options are contractual agreements that give the holder the right, but not the obligation, to buy or sell a fixed quantity of a commodity, at a fixed price, within a specified period of time. Options may either be standardized and exchange traded or customized and nonexchange traded. A collar is a combination of a purchased put option and a sold call option, which places a floor and a ceiling price for commodity sales being hedged. 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. 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 December 31, 2015 and 2014 , 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. At December 31, 2015 and 2014 , we had forward-starting interest-rate swaps with notional amounts totaling $400 million and $900 million , respectively, that have been designated as cash flow hedges of the variability of interest payments on a portion of forecasted debt issuances that may result from changes in the benchmark interest rate before the debt is issued. Upon our debt issuance in March 2015, we settled $500 million of our interest-rate swaps and realized a loss of $55.1 million , which is included in accumulated other comprehensive loss and will be amortized to interest expense over the term of the related debt. At December 31, 2015 , our remaining interest-rate swaps with notional amounts totaling $400 million have settlement dates of less than 12 months. In January 2016, we entered into forward-starting interest-rate swaps with notional amounts totaling $1.0 billion for the period of April 2016 through July 2018 and forward-starting interest-rate swaps with notional amounts totaling $500 million for the period of July 2018 through January 2019 that were designated as cash flow hedges to hedge the variability on our LIBOR-based interest payments. Fair Values of Derivative Instruments - The following table sets forth the fair values of our derivative instruments for the periods indicated: December 31, 2015 December 31, 2014 Assets (a) (Liabilities) (a) Assets (b) (Liabilities) (b) ( Thousands of dollars ) Derivatives designated as hedging instruments Commodity contracts Financial contracts $ 39,255 $ (1,440 ) $ 43,234 $ (1,137 ) Physical contracts 3,591 — 9,922 — Interest-rate contracts — (9,936 ) 2,288 (44,843 ) Total derivatives designated as hedging instruments 42,846 (11,376 ) 55,444 (45,980 ) Derivatives not designated as hedging instruments Commodity contracts Financial contracts 6,919 (6,586 ) — — Physical contracts — — — (23 ) Total derivatives not designated as hedging instruments 6,919 (6,586 ) — (23 ) Total derivatives $ 49,765 $ (17,962 ) $ 55,444 $ (46,003 ) (a) - Included on a net basis in other current assets or other current liabilities in our Consolidated Balance Sheets. (b) - Included on a net basis in other current assets, other 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: December 31, 2015 December 31, 2014 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 — (27.1 ) — (41.2 ) -Crude oil and NGLs ( MMBbl ) Futures, forwards and swaps — (2.3 ) — (0.5 ) Basis -Natural gas ( Bcf ) Futures and swaps — (27.1 ) — (41.2 ) Interest-rate contracts ( Millions of dollars ) Forward-starting swaps $ 400.0 $ — $ 900.0 $ — Derivatives not designated as hedging instruments: Fixed price -Crude oil and NGLs ( MMBbl ) Futures, forwards and swaps 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 December 31, 2015 , our Consolidated Balance Sheet reflected a net loss of $113.3 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 $41.5 million , which will be realized within the next 12 months as the forecasted transactions affect earnings and if commodity prices remain at the current levels. The amount deferred in accumulated other comprehensive loss attributable to our settled interest-rate swaps is a loss of $141.7 million , which will be recognized over the life of the long-term, fixed-rate debt, including losses of $15.7 million 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: Derivatives in Cash Flow Hedging Relationships Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Commodity contracts $ 70,065 $ 32,354 $ (14,475 ) Interest-rate contracts (22,565 ) (96,993 ) 46,616 Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives(effective portion) $ 47,500 $ (64,639 ) $ 32,141 Unrealized gain (loss) related to our equity-method investments are not included in the table above and were not material. 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) Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Commodity contracts Commodity sales revenues $ 81,089 $ (21,052 ) $ 1,689 Interest-rate contracts Interest expense (14,055 ) (10,601 ) (10,033 ) Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income on derivatives (effective portion) $ 67,034 $ (31,653 ) $ (8,344 ) Ineffectiveness related to our cash flow hedges was not material for the years ended December 31, 2015, 2014 and 2013 . 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. There were no gains or losses due to the discontinuance of cash flow hedge treatment during 2015, 2014 and 2013 . 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 as of December 31, 2015 . 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 December 31, 2015 , the net credit exposure from our derivative assets is primarily with investment-grade companies in the financial services sector.

PROPERTY, PLANT AND EQUIPMENT

PROPERTY, PLANT AND EQUIPMENT	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
PROPERTY, PLANT AND EQUIPMENT	E . PROPERTY, PLANT AND EQUIPMENT The following table sets forth our property, plant and equipment by property type, for the periods indicated: Estimated Useful Lives (Years) December 31, December 31, ( Thousands of dollars ) Nonregulated Gathering pipelines and related equipment 5 to 40 $ 2,961,388 $ 2,449,343 Processing and fractionation and related equipment 3 to 40 3,627,062 2,880,572 Storage and related equipment 5 to 54 456,437 478,276 Transmission pipelines and related equipment 5 to 54 416,391 518,585 General plant and other 2 to 60 186,358 142,276 Construction work in process — 690,179 1,233,808 Regulated Storage and related equipment 5 to 54 76,468 115,799 Natural gas transmission pipelines and related equipment 5 to 77 1,507,220 1,478,035 Natural gas liquids transmission pipelines and related equipment 5 to 88 4,208,121 3,822,799 General plant and other 2 to 54 94,461 63,424 Construction work in process — 83,461 194,700 Property, plant and equipment 14,307,546 13,377,617 Accumulated depreciation and amortization - nonregulated (1,219,435 ) (1,123,261 ) Accumulated depreciation and amortization - regulated (831,320 ) (718,823 ) Net property, plant and equipment $ 12,256,791 $ 11,535,533 The average depreciation rates for our regulated property are set forth, by segment, in the following table for the periods indicated: Years Ended December 31, 2015 2014 2013 Natural Gas Liquids 1.9% 2.0% 2.0% Natural Gas Pipelines 2.1% 2.1% 2.2% We incurred liabilities for construction work in process that had not been paid at December 31, 2015, 2014 and 2013 , of $115.7 million , $187.2 million and $226.7 million , respectively. Such amounts are not included in capital expenditures (less allowance for equity funds used during construction) on the Consolidated Statements of Cash Flows. Impairment Charges - Crude oil and natural gas producers have primarily focused their development efforts on crude oil and NGL-rich supply basins rather than in areas with dry natural gas production, such as the coal-bed methane production areas in the Powder River Basin. The reduced development activities and production declines in the dry natural gas area of the Powder River Basin have resulted in lower natural gas volumes available to be gathered. Due to the continued and greater than expected decline in volumes gathered in the coal-bed methane area of the Powder River Basin, we evaluated our assets and investments in this area for impairment and determined that we will cease operations of our wholly owned coal-bed methane natural gas gathering system in 2016. We recorded $63.5 million of noncash impairment charges on these long-lived assets in the fourth quarter 2015 in our Natural Gas Gathering and Processing segment. In addition, we recorded noncash impairment charges of approximately $20.2 million for previously idled assets in the Natural Gas Gathering and Processing and Natural Gas Liquids segments in the fourth quarter 2015, as our expectation for future use of these assets changed.

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
GOODWILL AND INTANGIBLE ASSETS	F . GOODWILL AND INTANGIBLE ASSETS Goodwill - The following table sets forth our goodwill, by segment, for the periods indicated: December 31, 2015 December 31, 2014 ( Thousands of dollars ) Natural Gas Gathering and Processing $ 112,141 $ 112,141 Natural Gas Liquids 247,566 247,566 Natural Gas Pipelines 129,011 129,011 Total goodwill $ 488,718 $ 488,718 Intangible Assets - Our intangible assets relate primarily to contracts acquired through acquisitions in our Natural Gas Gathering and Processing and Natural Gas Liquids segments, which are being amortized over periods of 20 to 40 years. Amortization expense for intangible assets for 2015, 2014 and 2013 was $11.9 million , $11.8 million and $8.7 million , respectively, and the aggregate amortization expense for each of the next five years is estimated to be approximately $11.9 million. The following table reflects the gross carrying amount and accumulated amortization of intangible assets for the periods presented: December 31, December 31, ( Thousands of dollars ) Gross intangible assets $ 426,068 $ 411,650 Accumulated amortization (89,909 ) (78,010 ) Net intangible assets $ 336,159 $ 333,640

SHORT-TERM BORROWINGS

SHORT-TERM BORROWINGS	12 Months Ended
	Dec. 31, 2015
Short-term Debt [Abstract]
SHORT-TERM BORROWINGS	G . 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. During the first quarter 2015, we increased the size of our Partnership Credit Agreement to $2.4 billion from $1.7 billion by exercising our option to increase the capacity of the facility through increased commitments from existing lenders and a commitment from one new lender. We had $14 million of letters of credit issued at December 31, 2015 and 2014 , $300.0 million of borrowings outstanding and approximately $1.8 billion capacity available at December 31, 2015 , and no borrowings outstanding at December 31, 2014 , under our Partnership Credit Agreement. The interest rate on our borrowings at December 31, 2015 , was 1.60 percent . 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. As a result of the West Texas LPG acquisition we completed in the fourth quarter 2014, the allowable ratio of indebtedness to adjusted EBITDA increased to 5.5 to 1 through the second quarter 2015. If 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 December 31, 2015 , our ratio of indebtedness to adjusted EBITDA was 4.4 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 - During the first quarter 2015, we increased the size of our commercial paper program to $2.4 billion from $ 1.7 billion . Amounts outstanding under our commercial paper program reduce the borrowing capacity under our Partnership Credit Agreement. At December 31, 2015 and 2014 , we had $246.3 million and $1.1 billion of commercial paper outstanding with weighted-average interest rates of 1.23 percent and 0.54 percent , respectively.

LONG-TERM DEBT

LONG-TERM DEBT	12 Months Ended
	Dec. 31, 2015
Long-term Debt, Unclassified [Abstract]
LONG-TERM DEBT	H . LONG-TERM DEBT All notes are senior unsecured obligations, ranking equally in right of payment with all of our existing and future unsecured senior indebtedness. The following table sets forth our long-term debt for the periods indicated: December 31, December 31, ( Thousands of dollars ) ONEOK Partners $650,000 at 3.25% due 2016 $ 650,000 $ 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 $500,000 at 8.625% due 2019 500,000 500,000 $300,000 at 3.8% due 2020 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 — $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 7.88% due 2022 51,907 59,557 Total long-term notes payable 6,851,907 6,059,557 Unamortized debt issuance costs and discounts (48,945 ) (47,675 ) Current maturities (107,650 ) (7,650 ) Long-term debt $ 6,695,312 $ 6,004,232 The aggregate maturities of long-term debt outstanding as of December 31, 2015, for the years 2016 through 2020 are shown below: ONEOK Partners Guardian Pipeline Total ( Millions of dollars ) 2016 $ 1,100.0 $ 7.7 $ 1,107.7 2017 $ 400.0 $ 7.7 $ 407.7 2018 $ 425.0 $ 7.7 $ 432.7 2019 $ 500.0 $ 7.7 $ 507.7 2020 $ 300.0 $ 7.7 $ 307.7 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, which may be drawn by April 7, 2016. The Term Loan Agreement is intended to effectively refinance $1.0 billion of our $650 million , 3.25 percent senior notes, which matured February 1, 2016, and our $450 million , 6.15 percent senior notes due October 1, 2016. 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 will accrue at LIBOR plus 130.0 basis points . 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 provides an option to prepay, without penalty or premium, the amount outstanding, or any portion thereof. At December 31, 2015, $1.0 billion of our senior notes due in 2016 have been reflected as long-term debt in our Consolidated Balance Sheet, as we have the intent and ability to refinance the debt, and the remaining $100.0 million is reflected in current maturities of long-term debt. 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 offering expenses, were approximately $792.3 million . We used the proceeds to repay amounts outstanding under our commercial paper program and for general partnership purposes. In September 2013, we completed an underwritten public offering of $1.25 billion of senior notes, consisting of $425 million , 3.2 percent senior notes due 2018, $425 million , 5.0 percent senior notes due 2023 and $400 million , 6.2 percent senior notes due 2043. A portion of the net proceeds from the offering of approximately $1.24 billion was used to repay amounts outstanding under our commercial paper program, and the balance was used for general partnership purposes, including but not limited to capital expenditures and acquisitions. Debt covenants - Our Term Loan Agreement contains substantially the same covenants as our Partnership Credit Agreement. Our senior notes are governed by an indenture, dated as of September 25, 2006, between us and Wells Fargo Bank, N.A., the trustee, as supplemented. The indenture does not limit the aggregate principal amount of debt securities that may be issued and provides that debt securities may be issued from time to time in one or more additional series. The indenture contains covenants including, among other provisions, limitations on our ability to place liens on our property or assets and to sell and lease back our property. The indenture includes an event of default upon acceleration of other indebtedness of $100 million or more. Such events of default would entitle the trustee or the holders of 25 percent in aggregate principal amount of any of our outstanding senior notes to declare those notes immediately due and payable in full. We may redeem our 6.15 percent senior notes due 2016 and our senior notes due 2019, 2036 and 2037, in whole or in part, at any time prior to their maturity at a redemption price equal to the principal amount, plus accrued and unpaid interest and a make-whole premium. The redemption price will never be less than 100 percent of the principal amount of the respective note plus accrued and unpaid interest to the redemption date. We may redeem our senior notes due 2017 and our senior notes due 2022 at par starting one month and three months, respectively, before their maturity dates. We may redeem our senior notes due 2041 at a redemption price equal to the principal amount, plus accrued and unpaid interest, starting six months before its maturity date. Prior to that date, we may redeem these notes, in whole or in part, at a redemption price equal to the principal amount, plus accrued and unpaid interest and a make-whole premium. We may redeem our senior notes due 2018, 2020, 2023, 2025, and 2043 at par, plus accrued and unpaid interest to the redemption date, starting one month, one month, three months, three months, and six months, respectively, before their maturity dates. Prior to these dates, we may redeem these notes, in whole or in part, at a redemption price equal to the principal amount, plus accrued and unpaid interest and a make-whole premium. The redemption price will never be less than 100 percent of the principal amount of the respective note plus accrued and unpaid interest to the redemption date. Our senior notes are senior unsecured obligations, ranking equally in right of payment with all of our existing and future unsecured senior indebtedness, and are structurally subordinate to any of the existing and future debt and other liabilities of any nonguarantor subsidiaries. ONEOK Partners Debt Guarantee - Our senior notes are guaranteed fully and unconditionally on a senior unsecured basis by the Intermediate Partnership. The guarantee ranks equally in right of payment to all of the Intermediate Partnership’s existing and future unsecured senior indebtedness. See Note R for additional information on the guarantee. Our long-term debt is nonrecourse to our general partner. Guardian Pipeline Senior Notes - These senior notes were issued under a master shelf agreement dated November 8, 2001, with certain financial institutions. Principal payments are due quarterly through 2022. Guardian Pipeline’s senior notes contain financial covenants that require the maintenance of certain financial ratios as defined in the master shelf agreement based on Guardian Pipeline’s financial position and results of operations. Upon any breach of these covenants, all amounts outstanding under the master shelf agreement may become due and payable immediately. At December 31, 2015, Guardian Pipeline was in compliance with its financial covenants . Other - We amortize premiums, discounts and expenses incurred in connection with the issuance of long-term debt consistent with the terms of the respective debt instrument.

EQUITY

EQUITY	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
EQUITY	I . 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 December 31, 2015 . 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 December 31, 2015 , we had approximately $138 million of registered common units available for issuance through our “at-the-market” equity program. 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. As a result of these transactions, ONEOK’s aggregate ownership interest in us increased to 41.2 percent at December 31, 2015 , from 37.8 percent at December 31, 2014 . In May 2014, we completed an underwritten public offering of 13.9 million common units at a public offering price of $52.94 per common unit, generating net proceeds of approximately $714.5 million . In conjunction with this issuance, ONEOK Partners GP contributed approximately $15.0 million in order to maintain its 2 percent general partner interest in us. We used the proceeds to repay commercial paper, fund our capital expenditures and for general partnership purposes. During the year ended December 31, 2014, we sold 7.9 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 $402.1 million , which were used for general partnership purposes. In August 2013, we completed an underwritten public offering of 11.5 million common units at a public offering price of $49.61 per common unit, generating net proceeds of approximately $553.4 million . In conjunction with this issuance, ONEOK Partners GP contributed approximately $11.6 million in order to maintain its 2 percent general partner interest in us. We used a portion of the proceeds from our August 2013 equity issuance to repay amounts outstanding under our commercial paper program, and the balance was used for general partnership purposes. During the year ended December 31, 2013, we sold 681,000 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 $36.1 million , which were used for general partnership purposes. 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 - The following table sets forth the quarterly cash distribution declared and paid on each of our common and Class B units during the periods indicated: Declared for Quarter Ending Distribution Per Unit Date Declared Date Paid December 31, 2015 $ 0.790 January 21, 2016 February 12, 2016 September 30, 2015 $ 0.790 October 21, 2015 November 13, 2015 June 30, 2015 $ 0.790 July 23, 2015 August 14, 2015 March 31, 2015 $ 0.790 April 16, 2015 May 15, 2015 December 31, 2014 $ 0.790 January 15, 2015 February 13, 2015 September 30, 2014 $ 0.775 October 23, 2014 November 14, 2014 June 30, 2014 $ 0.760 July 25, 2014 August 14, 2014 March 31, 2014 $ 0.745 April 18, 2014 May 15, 2014 December 31, 2013 $ 0.730 January 16, 2014 February 14, 2014 September 30, 2013 $ 0.725 October 23, 2013 November 14, 2013 June 30, 2013 $ 0.720 July 25, 2013 August 15, 2013 March 31, 2013 $ 0.715 April 18, 2013 May 15, 2013 December 31, 2012 $ 0.710 January 17, 2013 February 14, 2013 The following table shows our distributions paid during the periods indicated: Years Ended December 31, 2015 2014 2013 ( Thousands, except per unit amounts ) Distribution per unit $ 3.16 $ 3.01 $ 2.87 General partner distributions $ 24,610 $ 21,044 $ 18,193 Incentive distributions 371,500 304,999 251,664 Distributions to general partner 396,110 326,043 269,857 Limited partner distributions to ONEOK 310,230 279,292 266,302 Limited partner distributions to other unitholders 524,135 446,910 373,554 Total distributions paid $ 1,230,475 $ 1,052,245 $ 909,713 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: Years Ended December 31, 2015 2014 2013 ( Thousands, except per unit amounts ) Distribution per unit $ 3.16 $ 3.07 $ 2.89 General partner distributions $ 25,356 $ 22,109 $ 18,625 Incentive distributions 382,759 326,022 259,466 Distributions to general partner 408,115 348,131 278,091 Limited partner distributions to ONEOK 327,250 284,860 268,157 Limited partner distributions to other unitholders 532,405 472,466 384,988 Total distributions declared $ 1,267,770 $ 1,105,457 $ 931,236 Our Class B limited partner units are entitled to receive increased quarterly distributions equal to 110 percent of the distributions paid with respect to our common units. ONEOK, as the sole holder of our Class B limited partner units, has waived its right to receive the increased quarterly distributions on the Class B units. ONEOK retains the option to withdraw its waiver of increased distributions on Class B units at any time by giving us no less than 90 days advance notice. Any such withdrawal of the waiver will be effective with respect to any distribution on the Class B units declared or paid on or after the 90 days following delivery of the notice. The Class B units are eligible to convert into common units on a one-for-one basis at ONEOK’s option. If our common unitholders vote at any time to remove ONEOK or its affiliates as our general partner, quarterly distributions payable on the Class B limited partner units would increase to 123.5 percent of the distributions payable with respect to the common units, and distributions payable upon liquidation of the Class B limited partner units would increase to 123.5 percent of the distributions payable with respect to the common units. Our income is allocated to the general partner and the limited partners in accordance with their respective partnership percentages, after giving effect to any priority income allocations for incentive distributions that are allocated to the general partner. Noncontrolling Interest - In November 2014, we completed the acquisition of an 80 percent interest in the WTLPG. We consolidate WTLPG and have recorded noncontrolling interests in consolidated subsidiaries on our consolidated financial statements to recognize the portion of WTLPG that we do not own. Prior to November 2014, our noncontrolling interests in consolidated subsidiaries were not material.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Notes)	12 Months Ended
	Dec. 31, 2015
ACCUMULATED OTHER COMPREHENSIVE LOSS	J . ACCUMULATED OTHER COMPREHENSIVE LOSS The following table sets forth the balance in accumulated other comprehensive income (loss) for the periods indicated: Accumulated Other Comprehensive Loss (a) ( Thousands of dollars ) January 1, 2014 $ (58,837 ) Other comprehensive income (loss) before reclassifications (64,639 ) Amounts reclassified from accumulated other comprehensive income (loss) 31,653 Net current-period other comprehensive income (loss) attributable to ONEOK Partners (32,986 ) December 31, 2014 (91,823 ) Other comprehensive income (loss) before reclassifications 45,575 Amounts reclassified from accumulated other comprehensive income (loss) (67,034 ) Net current-period other comprehensive income (loss) attributable to ONEOK Partners (21,459 ) December 31, 2015 $ (113,282 ) (a) All amounts are attributable to unrealized gains (losses) in risk-management assets/liabilities. The following table sets forth the effect of reclassifications from accumulated other comprehensive income (loss) in our Consolidated Statements of Income for the periods indicated: Details about Accumulated Other Comprehensive Income (Loss) Components Year Ended December 31, Affected Line Item in the Consolidated Statements of Income 2015 2014 2013 ( Thousands of dollars ) Unrealized (gains) losses on risk-management assets/liabilities Commodity contracts $ (81,089 ) $ 21,052 $ (1,689 ) Commodity sales revenues Interest-rate contracts 14,055 10,601 10,033 Interest expense Total reclassifications for the period attributable to ONEOK Partners $ (67,034 ) $ 31,653 $ 8,344 Net income attributable to ONEOK Partners

LIMITED PARTNERS' NET INCOME PE

LIMITED PARTNERS' NET INCOME PER UNIT LIMITED PARTNERS' NET INCOME PER UNIT (Notes)	12 Months Ended
	Dec. 31, 2015
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
LIMITED PARTNERS' NET INCOME PER UNIT	K . 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 amount of incentive distributions allocated to our general partner totaled $382.8 million , $326.0 million and $259.5 million for 2015, 2014 and 2013 , respectively. 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 I .

INCOME TAXES

INCOME TAXES	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
INCOME TAXES	L . INCOME TAXES The following table sets forth our provision for income taxes for the periods indicated: Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Current income tax provision Federal $ — $ 59 $ 56 State (621 ) 1,777 5,358 Total current income tax provision (621 ) 1,836 5,414 Deferred income tax provision Federal 5,413 5,033 4,303 State (648 ) 5,799 1,141 Total deferred income tax provision 4,765 10,832 5,444 Total provision for income taxes $ 4,144 $ 12,668 $ 10,858 The following table is a reconciliation of our income tax provision for the periods indicated: Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Income before income taxes $ 602,016 $ 924,003 $ 814,841 Less: Net income attributable to noncontrolling interests 8,330 1,037 357 Income attributable to ONEOK Partners, L.P. before income taxes 593,686 922,966 814,484 Federal statutory income tax rate 35.0 % 35.0 % 35.0 % Provision for federal income taxes 207,790 323,038 285,069 Partnership earnings not subject to tax (202,143 ) (318,021 ) (280,992 ) State income taxes, net of federal benefit (2,078 ) 7,576 6,095 State deferred tax rate change, net of valuation allowance 810 — — Other, net (235 ) 75 686 Income tax provision $ 4,144 $ 12,668 $ 10,858 The following table sets forth the tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and liabilities for the periods indicated. Years Ended December 31, 2015 2014 ( Thousands of dollars ) Deferred tax assets Federal and state net operating loss $ 4,224 $ 3,179 Other 7 1,626 Total deferred tax assets 4,231 4,805 Deferred tax liabilities Excess of tax over book depreciation 67,265 61,120 Regulatory assets 49 1,962 Total deferred tax liabilities 67,314 63,082 Net deferred tax liabilities $ 63,083 $ 58,277

UNCONSOLIDATED AFFILIATES

UNCONSOLIDATED AFFILIATES	12 Months Ended
	Dec. 31, 2015
Equity Method Investments and Joint Ventures [Abstract]
UNCONSOLIDATED AFFILIATES	M . UNCONSOLIDATED AFFILIATES Investments in Unconsolidated Affiliates - The following table sets forth our investments in unconsolidated affiliates for the periods indicated: Net Ownership Interest December 31, December 31, ( Thousands of dollars ) Northern Border Pipeline 50% $ 363,231 $ 387,253 Overland Pass Pipeline Company 50% 459,354 466,977 Other Various 125,636 278,423 Investments in unconsolidated affiliates (a) $ 948,221 $ 1,132,653 (a) - Equity-method goodwill (Note A ) was $40.1 million and $170.9 million at December 31, 2015 and 2014 , respectively. Equity in Net Earnings from Investments and Impairments - The following table sets forth our equity in net earnings from investments for the periods indicated: Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Northern Border Pipeline $ 66,941 $ 69,819 $ 65,046 Overland Pass Pipeline Company 37,783 25,906 20,461 Other 20,576 21,690 25,010 Equity in net earnings from investments $ 125,300 $ 117,415 $ 110,517 Impairment of equity investments $ (180,583 ) $ (76,412 ) $ — Unconsolidated Affiliates Financial Information - The following tables set forth summarized combined financial information of our unconsolidated affiliates for the periods indicated: December 31, December 31, ( Thousands of dollars ) Balance Sheet Current assets $ 149,439 $ 153,293 Property, plant and equipment, net $ 2,556,559 $ 2,440,714 Other noncurrent assets $ 23,722 $ 35,668 Current liabilities $ 211,037 $ 95,026 Long-term debt $ 425,521 $ 428,385 Other noncurrent liabilities $ 69,356 $ 73,767 Accumulated other comprehensive loss $ (5,669 ) $ (2,063 ) Owners’ equity $ 2,029,475 $ 2,034,560 Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Income Statement Operating revenues $ 524,496 $ 548,491 $ 528,665 Operating expenses (a) $ 304,930 $ 309,990 $ 256,292 Net income (a) $ 200,064 $ 214,410 $ 248,998 Distributions paid to us $ 155,918 $ 139,019 $ 137,498 (a) Includes long-lived asset impairment charges in 2015 and 2014. We incurred expenses in transactions with unconsolidated affiliates of $104.7 million , $62.0 million and $53.8 million for 2015, 2014 and 2013 , respectively, primarily related to Overland Pass Pipeline Company and Northern Border Pipeline. Accounts payable to our equity-method investees at December 31, 2015 and 2014, was $8.0 million and $20.5 million , respectively. 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. 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. During 2013, we made equity contributions to Northern Border Pipeline of $30.8 million . Roadrunner Gas Transmission - In March 2015, we entered into a 50-50 joint venture with a subsidiary of 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 year ended December 31, 2015, we contributed approximately $30 million to Roadrunner. The Roadrunner limited liability agreement provides that distributions to members are made on a pro rata basis according to each member’s ownership interest. Cash distributions are paid within 45 days following the end of each quarter. 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. Impairment Charges - Crude oil and natural gas producers have primarily focused their development efforts on crude oil and NGL-rich supply basins rather than in areas with dry natural gas production, such as the coal-bed methane production areas in the Powder River Basin. The reduced development activities and production declines in the dry natural gas area of the Powder River Basin have resulted in lower natural gas volumes available to be gathered. Due to the continued and greater than expected decline in volumes gathered in the coal-bed methane area of the Powder River Basin, we evaluated our assets and investments in this area and determined that we will cease operations of our wholly owned coal-bed methane natural gas gathering system in 2016. Bighorn Gas Gathering, in which we own a 49 percent equity interest, and Fort Union Gas Gathering, in which we own a 37 percent equity interest, are both partially supplied with volumes from our wholly owned coal-bed methane natural gas gathering system. We own a 35 percent equity interest in Lost Creek Gathering Company, which also is located in a dry natural gas area. We reviewed our Bighorn Gas Gathering, Fort Union Gas Gathering and Lost Creek Gathering Company equity investments and recorded noncash impairment charges of $180.6 million in the fourth quarter 2015. The remaining net book value of our equity investments in this dry natural gas area is $35.0 million . During 2014, Bighorn Gas Gathering recorded an impairment of its underlying assets when the operator determined that the volume decline would be sustained for the foreseeable future. As a result, we reviewed our equity investment in Bighorn Gas Gathering for impairment and recorded noncash impairment charges of $76.4 million in 2014. The 2014 impairment charges have been reclassified in the consolidated financial statements and notes to conform to the current year presentation. There were no impairments to investments in unconsolidated affiliates in 2013.

RELATED-PARTY TRANSACTIONS

RELATED-PARTY TRANSACTIONS	12 Months Ended
	Dec. 31, 2015
Related Party Transactions [Abstract]
RELATED-PARTY TRANSACTIONS	N . RELATED-PARTY TRANSACTIONS Prior to April 1, 2014, our Natural Gas Gathering and Processing segment sold natural gas to ONEOK and its subsidiaries, and our Natural Gas Pipelines segment provided transportation and storage services to ONEOK and its subsidiaries. Additionally, our Natural Gas Gathering and Processing segment and Natural Gas Liquids segment purchased a portion of the natural gas used in their operations from ONEOK and its subsidiaries. On January 31, 2014, ONEOK completed the separation of its former natural gas distribution business into ONE Gas. ONE Gas was an affiliate prior to this separation. Commodity sales and services revenues in the Consolidated Statements of Income for the one month ended January 31, 2014, and for the year ended December 31, 2013, for transactions with ONE Gas prior to the separation are reflected as affiliate transactions. Transactions with ONE Gas that occurred after the separation are reflected as unaffiliated, third-party transactions. On March 31, 2014, ONEOK completed the wind down of ONEOK Energy Services Company, a subsidiary of ONEOK. For the first quarter 2014 and the year ended December 31, 2013, we had transactions with ONEOK Energy Services Company, which are reflected as affiliate 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. Beginning in the second quarter 2014, ONEOK allocates substantially all of its general overhead costs to us as a result of ONEOK’s separation of its natural gas distribution business and the wind down of its energy services business in the first quarter 2014. For the first quarter 2014 and the year ended December 31, 2013, it is not practicable to determine what these general overhead costs would have been on a stand-alone basis. All costs directly charged or allocated to us are included in our Consolidated Statements of Income. The following table sets forth the transactions with related parties for the periods indicated: Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Revenues $ — $ 53,526 $ 340,743 Expenses Cost of sales and fuel $ — $ 10,835 $ 37,963 Operating expenses 368,346 330,541 265,448 Total expenses $ 368,346 $ 341,376 $ 303,411 ONEOK Partners GP made additional general partner contributions to us of approximately $21.0 million , $23.2 million and $12.4 million in 2015, 2014 and 2013 , respectively, to maintain its 2 percent general partner interest in connection with the issuances of common units. See Note I for additional information about cash distributions paid to ONEOK for its general partner and limited partner interests.

COMMITMENTS AND CONTINGENCIES

COMMITMENTS AND CONTINGENCIES	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	O . COMMITMENTS AND CONTINGENCIES Commitments - Operating leases represent future minimum lease payments under noncancelable leases covering office space and pipeline equipment. Rental expense in 2015, 2014 and 2013 was not material. We have no material operating leases. Firm transportation and storage contracts are fixed-price contracts that provide us with firm transportation and storage capacity. The following table sets forth our firm transportation and storage contract payments for our continuing operations for the periods indicated: Firm Transportation and Storage Contracts ( Millions of dollars ) 2016 $ 45.8 2017 42.1 2018 40.6 2019 36.2 2020 35.8 Thereafter 47.9 Total $ 248.4 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	12 Months Ended
	Dec. 31, 2015
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
SEGMENTS	P . 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 - We evaluate performance based principally on each segment’s operating income and equity in net earnings. The accounting policies of the segments are described in Note A . As a result of ONEOK’s separation of its natural gas distribution business into a stand-alone publicly traded company called ONE Gas on January 31, 2014, transactions with ONE Gas subsequent to the separation are reflected as sales to unaffiliated customers. Customers - The primary customers for our Natural Gas Gathering and Processing segment are major and independent crude oil and natural gas production companies. Our Natural Gas Liquids segment’s customers are primarily NGL and natural gas gathering and processing companies, major and independent crude oil and natural gas production companies, propane distributors, ethanol producers and petrochemical, refining and NGL marketing companies. Our Natural Gas Pipelines segment’s customers include natural gas distribution, electric-generation, natural gas marketing, industrial and major and independent crude oil and natural gas production companies. For the years ended December 31, 2015, 2014 and 2013 , we had no single customer from which we received 10 percent or more of our consolidated revenues. See Note N for additional information about our sales to affiliated customers. Operating Segment Information - The following tables set forth certain selected financial information for our operating segments for the periods indicated: Year Ended December 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 $ 1,187,390 $ 6,248,002 $ 325,676 $ — $ 7,761,068 Intersegment revenues 649,726 331,697 6,771 (988,194 ) — Total revenues 1,837,116 6,579,699 332,447 (988,194 ) 7,761,068 Cost of sales and fuel (exclusive of items shown separately below) 1,265,617 5,328,256 34,481 (987,302 ) 5,641,052 Operating costs 272,418 314,505 105,720 (467 ) 692,176 Depreciation and amortization 150,008 158,709 43,479 — 352,196 Impairment of long-lived assets 73,681 9,992 — — 83,673 Gain (loss) on sale of assets 2,775 (939 ) 4,272 — 6,108 Operating income $ 78,167 $ 767,298 $ 153,039 $ (425 ) $ 998,079 Equity in net earnings from investments $ 17,863 $ 38,696 $ 68,741 $ — $ 125,300 Impairment of equity investments $ (180,583 ) $ — $ — $ — $ (180,583 ) Investments in unconsolidated affiliates $ 73,920 $ 482,672 $ 391,629 $ — $ 948,221 Total assets $ 5,123,450 $ 8,017,799 $ 1,844,401 $ (58,064 ) $ 14,927,586 Noncontrolling interests in consolidated subsidiaries $ 4,041 $ 160,084 $ — $ — $ 164,125 Capital expenditures $ 887,938 $ 226,135 $ 58,215 $ 13,835 $ 1,186,123 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $954.8 million , of which $770.1 million related to sales within the segment, cost of sales and fuel of $412.6 million and operating income of $306.9 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $266.9 million , cost of sales and fuel of $31.1 million and operating income of $103.7 million . Year Ended December 31, 2014 Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Other and Eliminations Total ( Thousands of dollars ) Sales to unaffiliated customers $ 1,478,729 $ 10,329,609 $ 329,801 $ — $ 12,138,139 Sales to affiliated customers 41,214 — 12,312 — 53,526 Intersegment revenues 1,447,665 215,772 8,343 (1,671,780 ) — Total revenues 2,967,608 10,545,381 350,456 (1,671,780 ) 12,191,665 Cost of sales and fuel (exclusive of items shown separately below) 2,305,723 9,435,296 21,935 (1,674,406 ) 10,088,548 Operating costs 257,658 296,402 111,037 4,560 669,657 Depreciation and amortization 123,847 124,071 43,318 — 291,236 Gain (loss) on sale of assets 219 (572 ) 6,786 166 6,599 Operating income $ 280,599 $ 689,040 $ 180,952 $ (1,768 ) $ 1,148,823 Equity in net earnings from investments $ 20,271 $ 27,326 $ 69,818 $ — $ 117,415 Impairment of equity investments $ (76,412 ) $ — $ — $ — $ (76,412 ) Investments in unconsolidated affiliates $ 254,818 $ 490,582 $ 387,253 $ — $ 1,132,653 Total assets $ 4,911,283 $ 8,143,575 $ 1,823,713 $ (278,171 ) $ 14,600,400 Noncontrolling interests in consolidated subsidiaries $ 4,251 $ 163,671 $ — $ 15 $ 167,937 Capital expenditures $ 898,896 $ 798,048 $ 42,991 $ 6,055 $ 1,745,990 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $695.9 million , of which $598.1 million related to sales within the segment, cost of sales and fuel of $309.4 million and operating income of $196.1 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $290.0 million , cost of sales and fuel of $47.7 million and operating income of $106.5 million . Year Ended December 31, 2013 Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Other and Eliminations Total ( Thousands of dollars ) Sales to unaffiliated customers $ 665,169 $ 10,644,117 $ 219,244 $ — $ 11,528,530 Sales to affiliated customers 238,600 — 102,143 — 340,743 Intersegment revenues 1,147,713 133,910 4,127 (1,285,750 ) — Total revenues 2,051,482 10,778,027 325,514 (1,285,750 ) 11,869,273 Cost of sales and fuel (exclusive of items shown separately below) 1,550,855 9,908,089 39,795 (1,276,526 ) 10,222,213 Operating costs 193,293 236,638 101,182 (9,600 ) 521,513 Depreciation and amortization 103,962 89,240 43,541 — 236,743 Loss on sale of assets 436 843 10,602 — 11,881 Operating income $ 203,808 $ 544,903 $ 151,598 $ 376 $ 900,685 Equity in net earnings from investments $ 23,493 $ 21,978 $ 65,046 $ — $ 110,517 Investments in unconsolidated affiliates $ 333,179 $ 491,856 $ 404,803 $ — $ 1,229,838 Total assets $ 3,949,813 $ 6,938,633 $ 1,817,445 $ 118,269 $ 12,824,160 Noncontrolling interests in consolidated subsidiaries $ 4,521 $ — $ — $ 15 $ 4,536 Capital expenditures $ 774,379 $ 1,128,345 $ 34,699 $ 1,903 $ 1,939,326 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $534.8 million , of which $449.9 million related to sales within the segment, cost of sales and fuel of $207.4 million and operating income of $190.5 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $246.9 million , cost of sales and fuel of $29.3 million and operating income of $90.5 million .

QUARTERLY FINANCIAL DATA (UNAUD

QUARTERLY FINANCIAL DATA (UNAUDITED)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Data [Abstract]
QUARTERLY FINANCIAL DATA (UNAUDITED)	Q . QUARTERLY FINANCIAL DATA (UNAUDITED) Year Ended December 31, 2015 First Quarter Second Quarter Third Quarter Fourth Quarter ( Thousands of dollars, except per unit amounts ) Revenues $ 1,804,759 $ 2,127,507 $ 1,898,418 $ 1,930,384 Net income $ 147,032 $ 211,610 $ 229,665 $ 9,565 Net income attributable to ONEOK Partners, L.P. $ 145,594 $ 209,770 $ 226,961 $ 7,217 Limited partners’ per unit net income (loss) $ 0.21 $ 0.44 $ 0.45 $ (0.33 ) The fourth quarter 2015 includes noncash impairment charges of $264.3 million related to long-lived assets and equity investments. Year Ended December 31, 2014 First Quarter Second Quarter Third Quarter Fourth Quarter ( Thousands of dollars, except per unit amounts ) Revenues $ 3,162,303 $ 3,065,735 $ 3,119,369 $ 2,844,258 Net income $ 265,468 $ 214,511 $ 167,320 $ 264,036 Net income attributable to ONEOK Partners, L.P. $ 265,392 $ 214,434 $ 167,247 $ 263,225 Limited partners’ per unit net income $ 0.81 $ 0.54 $ 0.32 $ 0.67 The third quarter 2014 includes noncash impairment charges of $76.4 million related to equity investments.

SUPPLEMENTAL CONDENSED CONSOLID

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION	12 Months Ended
	Dec. 31, 2015
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Supplemental Condensed Consolidating Financial Information	R . 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. Our Intermediate Partnership guarantees our senior notes and borrowings, if any, under the Partnership Credit Agreement. The Intermediate Partnership’s guarantee 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 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 Year Ended December 31, 2015 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ 6,098.3 $ — $ 6,098.3 Services — — 1,662.8 — 1,662.8 Total revenues — — 7,761.1 — 7,761.1 Cost of sales and fuel (exclusive of items shown separately below) — — 5,641.1 — 5,641.1 Impairment of long-lived assets — — 83.7 — 83.7 Operating expenses — — 1,044.3 — 1,044.3 Gain (loss) on sale of assets — — 6.1 — 6.1 Operating income — — 998.1 — 998.1 Equity in net earnings from investments 589.5 589.5 58.4 (1,112.1 ) 125.3 Impairment of equity investments — — (180.6 ) — (180.6 ) Other income (expense), net 371.0 371.0 (1.9 ) (742.0 ) (1.9 ) Interest expense (371.0 ) (371.0 ) (338.9 ) 742.0 (338.9 ) Income before income taxes 589.5 589.5 535.1 (1,112.1 ) 602.0 Income taxes — — (4.1 ) — (4.1 ) Net income 589.5 589.5 531.0 (1,112.1 ) 597.9 Less: Net income attributable to noncontrolling interests — — 8.4 — 8.4 Net income attributable to ONEOK Partners, L.P. $ 589.5 $ 589.5 $ 522.6 $ (1,112.1 ) $ 589.5 Year Ended December 31, 2014 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ 10,725.0 $ — $ 10,725.0 Services — — 1,466.7 — 1,466.7 Total revenues — — 12,191.7 — 12,191.7 Cost of sales and fuel (exclusive of items shown separately below) — — 10,088.6 — 10,088.6 Operating expenses — — 960.9 — 960.9 Gain (loss) on sale of assets — — 6.6 — 6.6 Operating income — — 1,148.8 — 1,148.8 Equity in net earnings from investments 910.3 910.3 47.6 (1,750.8 ) 117.4 Impairment of equity investments — — (76.4 ) — (76.4 ) Other income (expense), net 331.7 331.7 16.1 (663.4 ) 16.1 Interest expense,net (331.7 ) (331.7 ) (281.9 ) 663.4 (281.9 ) Income before income taxes 910.3 910.3 854.2 (1,750.8 ) 924.0 Income taxes — — (12.7 ) — (12.7 ) Net income 910.3 910.3 841.5 (1,750.8 ) 911.3 Less: Net income attributable to noncontrolling interests — — 1.0 — 1.0 Net income attributable to ONEOK Partners, L.P. $ 910.3 $ 910.3 $ 840.5 $ (1,750.8 ) $ 910.3 Year Ended December 31, 2013 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ 10,549.2 $ — $ 10,549.2 Services — — 1,320.1 — 1,320.1 Total revenues — — 11,869.3 — 11,869.3 Cost of sales and fuel (exclusive of items shown separately below) — — 10,222.2 — 10,222.2 Operating expenses — — 758.3 — 758.3 Gain (loss) on sale of assets — — 11.9 — 11.9 Operating income — — 900.7 — 900.7 Equity in net earnings from investments 803.6 803.6 45.5 (1,542.2 ) 110.5 Other income (expense), net 287.6 287.6 40.3 (575.2 ) 40.3 Interest expense (287.6 ) (287.6 ) (236.7 ) 575.2 (236.7 ) Income before income taxes 803.6 803.6 749.8 (1,542.2 ) 814.8 Income taxes — — (10.8 ) — (10.8 ) Net income 803.6 803.6 739.0 (1,542.2 ) 804.0 Less: Net income attributable to noncontrolling interests — — 0.4 — 0.4 Net income attributable to ONEOK Partners, L.P. $ 803.6 $ 803.6 $ 738.6 $ (1,542.2 ) $ 803.6 Condensed Consolidating Statements of Comprehensive Income Year Ended December 31, 2015 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 589.5 $ 589.5 $ 531.0 $ (1,112.1 ) $ 597.9 Other comprehensive income (loss) Unrealized gains (losses) on derivatives 45.6 68.1 68.1 (136.2 ) 45.6 Realized (gains) losses on derivatives recognized in net income (67.0 ) (81.1 ) (81.1 ) 162.2 (67.0 ) Total other comprehensive income (loss) (21.4 ) (13.0 ) (13.0 ) 26.0 (21.4 ) Comprehensive income 568.1 576.5 518.0 (1,086.1 ) 576.5 Less: Comprehensive income attributable to noncontrolling interests — — 8.4 — 8.4 Comprehensive income attributable to ONEOK Partners, L.P. $ 568.1 $ 576.5 $ 509.6 $ (1,086.1 ) $ 568.1 Year Ended December 31, 2014 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 910.3 $ 910.3 $ 841.5 $ (1,750.8 ) $ 911.3 Other comprehensive income (loss) Unrealized gains (losses) on derivatives (64.6 ) 32.4 32.4 (64.8 ) (64.6 ) Realized (gains) losses on derivatives recognized in net income 31.6 21.1 21.1 (42.2 ) 31.6 Total other comprehensive income (loss) (33.0 ) 53.5 53.5 (107.0 ) (33.0 ) Comprehensive income 877.3 963.8 895.0 (1,857.8 ) 878.3 Less: Comprehensive income attributable to noncontrolling interests — — 1.0 — 1.0 Comprehensive income attributable to ONEOK Partners, L.P. $ 877.3 $ 963.8 $ 894.0 $ (1,857.8 ) $ 877.3 Year Ended December 31, 2013 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 803.6 $ 803.6 $ 739.0 $ (1,542.2 ) $ 804.0 Other comprehensive income (loss) Unrealized gains (losses) on derivatives 32.1 (14.5 ) (14.5 ) 29.0 32.1 Realized (gains) losses on derivatives recognized in net income 8.4 (1.7 ) (1.7 ) 3.4 8.4 Total other comprehensive income (loss) 40.5 (16.2 ) (16.2 ) 32.4 40.5 Comprehensive income 844.1 787.4 722.8 (1,509.8 ) 844.5 Less: Comprehensive income attributable to noncontrolling interests — — 0.4 — 0.4 Comprehensive income attributable to ONEOK Partners, L.P. $ 844.1 $ 787.4 $ 722.4 $ (1,509.8 ) $ 844.1 Condensed Consolidating Balance Sheets December 31, 2015 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 Materials and supplies — — 76.7 — 76.7 Other current assets 4.1 — 67.8 — 71.9 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 December 31, 2014 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total Assets ( Millions of dollars ) Current assets Cash and cash equivalents $ — $ 42.5 $ — $ — $ 42.5 Accounts receivable, net — — 735.8 — 735.8 Affiliate receivables — — 8.6 — 8.6 Natural gas and natural gas liquids in storage — — 134.1 — 134.1 Materials and supplies — — 55.8 — 55.8 Other current assets 1.9 — 107.3 — 109.2 Total current assets 1.9 42.5 1,041.6 — 1,086.0 Property, plant and equipment Property, plant and equipment — — 13,377.6 — 13,377.6 Accumulated depreciation and amortization — — 1,842.1 — 1,842.1 Net property, plant and equipment — — 11,535.5 — 11,535.5 Investments and other assets Intercompany notes receivable 8,843.3 7,579.0 — (16,422.3 ) — Other assets 4,250.1 5,469.8 1,590.3 (9,331.3 ) 1,978.9 Total investments and other assets 13,093.4 13,048.8 1,590.3 (25,753.6 ) 1,978.9 Total assets $ 13,095.3 $ 13,091.3 $ 14,167.4 $ (25,753.6 ) $ 14,600.4 Liabilities and equity Current liabilities Current maturities of long-term debt $ — $ — $ 7.7 $ — $ 7.7 Short-term borrowings 1,055.3 — — — 1,055.3 Accounts payable — — 874.7 — 874.7 Affiliate payables — — 36.1 — 36.1 Other current liabilities 136.8 — 225.5 — 362.3 Total current liabilities 1,192.1 — 1,144.0 — 2,336.1 Intercompany debt — 8,843.3 7,579.0 (16,422.3 ) — Long-term debt, excluding current maturities 5,952.4 — 51.9 — 6,004.3 Deferred credits and other liabilities — — 141.3 — 141.3 Commitments and contingencies Equity Equity excluding noncontrolling interests in consolidated subsidiaries 5,950.8 4,248.0 5,083.3 (9,331.3 ) 5,950.8 Noncontrolling interests in consolidated subsidiaries — — 167.9 — 167.9 Total equity 5,950.8 4,248.0 5,251.2 (9,331.3 ) 6,118.7 Total liabilities and equity $ 13,095.3 $ 13,091.3 $ 14,167.4 $ (25,753.6 ) $ 14,600.4 Condensed Consolidating Statements of Cash Flows Year Ended December 31, 2015 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 1,196.7 $ 66.9 $ 1,038.9 $ (1,230.5 ) $ 1,072.0 Investing activities Capital expenditures — — (1,186.1 ) — (1,186.1 ) Other investing activities — 24.1 (26.5 ) — (2.4 ) Cash provided by (used in) investing activities — 24.1 (1,212.6 ) — (1,188.5 ) Financing activities Cash distributions: General and limited partners (1,230.5 ) (1,230.5 ) — 1,230.5 (1,230.5 ) Noncontrolling interests — — (11.7 ) — (11.7 ) Intercompany borrowings (advances), net (1,295.1 ) 1,102.1 193.0 — — Borrowing (repayment) of short-term borrowings, net (509.0 ) — — — (509.0 ) Issuance of long-term debt, net of discounts 798.9 — — — 798.9 Debt financing costs (7.7 ) — — — (7.7 ) Repayment of long-term debt — — (7.6 ) — (7.6 ) Issuance of common units, net of issuance costs 1,025.7 — — — 1,025.7 Contribution from general partner 21.0 — — — 21.0 Cash provided by (used in) financing activities (1,196.7 ) (128.4 ) 173.7 1,230.5 79.1 Change in cash and cash equivalents — (37.4 ) — — (37.4 ) Cash and cash equivalents at beginning of period — 42.5 — — 42.5 Cash and cash equivalents at end of period $ — $ 5.1 $ — $ — $ 5.1 Year Ended December 31, 2014 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 1,155.7 $ 69.8 $ 1,136.5 $ (1,052.2 ) $ 1,309.8 Investing activities Capital expenditures — — (1,746.0 ) — (1,746.0 ) Other investing activities — 17.7 (804.7 ) — (787.0 ) Cash provided by (used in) investing activities — 17.7 (2,550.7 ) — (2,533.0 ) Financing activities Cash distributions: General and limited partners (1,052.2 ) (1,052.2 ) — 1,052.2 (1,052.2 ) Noncontrolling interests — — (0.6 ) — (0.6 ) Intercompany borrowings (advances), net (2,295.2 ) 872.7 1,422.5 — — Borrowing (repayment) of short-term borrowings, net 1,055.3 — — — 1,055.3 Repayment of long-term debt — — (7.7 ) — (7.7 ) Issuance of common units, net of issuance costs 1,113.1 — — — 1,113.1 Contribution from general partner 23.3 — — — 23.3 Cash provided by (used in) financing activities (1,155.7 ) (179.5 ) 1,414.2 1,052.2 1,131.2 Change in cash and cash equivalents — (92.0 ) — — (92.0 ) Cash and cash equivalents at beginning of period — 134.5 — — 134.5 Cash and cash equivalents at end of period $ — $ 42.5 $ — $ — $ 42.5 Year Ended December 31, 2013 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 870.7 $ 65.1 $ 981.6 $ (909.7 ) $ 1,007.7 Investing activities Capital expenditures — (2.6 ) (1,936.7 ) — (1,939.3 ) Other investing activities — (11.4 ) (375.4 ) — (386.8 ) Cash provided by (used in) investing activities — (14.0 ) (2,312.1 ) — (2,326.1 ) Financing activities Cash distributions: General and limited partners (909.7 ) (909.7 ) — 909.7 (909.7 ) Noncontrolling interests — — (0.6 ) — (0.6 ) Intercompany borrowings (advances), net (1,794.8 ) 456.0 1,338.8 — — Issuance of long-term debt, net of discounts 1,247.8 — — — 1,247.8 Debt financing costs (10.2 ) — — — (10.2 ) Repayment of long-term debt — — (7.7 ) — (7.7 ) Issuance of common units, net of issuance costs 583.9 — — — 583.9 Contribution from general partner 12.3 — — — 12.3 Cash provided by (used in) financing activities (870.7 ) (453.7 ) 1,330.5 909.7 915.8 Change in cash and cash equivalents — (402.6 ) — — (402.6 ) Cash and cash equivalents at beginning of period — 537.1 — — 537.1 Cash and cash equivalents at end of period $ — $ 134.5 $ — $ — $ 134.5

SUMMARY OF SIGNIFICANT ACCOUN27

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	12 Months Ended
	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Consolidation	Consolidation - Our consolidated financial statements include the accounts of ONEOK Partners and our subsidiaries over which we have control or are the primary beneficiary. All significant intercompany balances and transactions have been eliminated in consolidation. Investments in unconsolidated affiliates are accounted for using the equity method if we have the ability to exercise significant influence over operating and financial policies of our investee. Under this method, an investment is carried at its acquisition cost and adjusted each period for contributions made, distributions received and our share of the investee’s comprehensive income. For the investments we account for under the equity method, the premium or excess cost over underlying fair value of net assets is referred to as equity-method goodwill. Impairment of equity investments is recorded when the impairments are other than temporary. These amounts are recorded as investments in unconsolidated affiliates on our accompanying Consolidated Balance Sheets. See Note M for disclosures of our unconsolidated affiliates. Distributions paid to us from our unconsolidated affiliates are classified as operating activities on our Consolidated Statements of Cash Flows until the cumulative distributions exceed our proportionate share of income from the unconsolidated affiliate since the date of our initial investment. The amount of cumulative distributions paid to us that exceeds our cumulative proportionate share of income in each period represents a return of investment and is classified as an investing activity on our Consolidated Statements of Cash Flows.
Use of Estimates	Use of Estimates - The preparation of our consolidated financial statements and related disclosures in accordance with GAAP requires us to make estimates and assumptions with respect to values or conditions that cannot be known with certainty that affect the reported amount of assets and liabilities, and the disclosure of contingent assets and liabilities at the date of the consolidated financial statements. These estimates and assumptions also affect the reported amounts of revenue and expenses during the reporting period. Items that may be estimated include, but are not limited to, the economic useful life of assets, fair value of assets, liabilities and equity-method investments, provisions for uncollectible accounts receivable, unbilled revenues and cost of goods sold, expenses for services received but for which no invoice has been received, the results of litigation and various other recorded or disclosed amounts. We evaluate these estimates on an ongoing basis using historical experience, consultation with experts and other methods we consider reasonable based on the particular circumstances. Nevertheless, actual results may differ significantly from the estimates. Any effects on our financial position or results of operations from revisions to these estimates are recorded in the period when the facts that give rise to the revision become known.
Fair Value Measurements	Fair Value Measurements - We define fair value as the price that would be received from the sale of an asset or the transfer of a liability in an orderly transaction between market participants at the measurement date. We use 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 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. See Note C for discussion of our fair value measurements.
Cash and Cash Equivalents	Cash and Cash Equivalents - Cash equivalents consist of highly liquid investments, which are readily convertible into cash and have original maturities of three months or less.
Revenue Recognition	Revenue Recognition - Our reportable segments recognize revenue when services are rendered or product is delivered. Our Natural Gas Gathering and Processing segment records revenues when natural gas is processed in or transported through our facilities. Our Natural Gas Liquids segment records revenues based upon contracted services and actual volumes exchanged or stored under service agreements in the period services are provided. A portion of our revenues for our Natural Gas Pipelines segment and our Natural Gas Liquids segment are recognized based upon contracted capacity and contracted volumes transported and stored under service agreements in the period services are provided. We disaggregate revenue on the Consolidated Statements of Income as follows: • Commodity sales - Commodity sales represent the sale of NGLs, condensate and residue natural gas. The commodities are primarily obtained as compensation for or related to providing services. Commodity sales are recognized upon delivery or title transfer to the customer, when revenue recognition criteria are met. • Service revenue - Service revenue represents the fees generated from the performance of our services listed above. We enter into a variety of contract types that provide commodity sales and service revenue. We provide services primarily under the following types of contracts: • Fee based - Under fee-based arrangements, we receive a fee or fees for one or more of the following services: gathering, compression, processing, transmission and storage of natural gas; and gathering, transportation, fractionation, exchange and storage of NGLs. The revenue we earn from these arrangements generally is directly related to the volume of natural gas and NGLs that flow through our systems and facilities, and is not normally directly dependent on commodity prices. However, to the extent a sustained decline in commodity prices results in a decline in volumes, our revenues from these arrangements would be reduced. In addition, many of our arrangements provide for fixed fee, minimum volume or firm demand charges. Fee-based arrangements are reported as service revenue on the Consolidated Statements of Income. • Percent-of-proceeds - Under POP arrangements in our Natural Gas Gathering and Processing segment, we gather and process natural gas on behalf of producers; sell the resulting residue natural gas, condensate and NGLs at market prices; and remit to producers an agreed-upon percentage of the net proceeds resulting from the sale. The agreed-upon percentage remitted to the producer is reported as cost of sales on the Consolidated Statements of Income. In other cases, instead of remitting cash payments to the producer, we deliver an agreed-upon percentage of the commodities to the producer (take-in-kind agreements) and sell the volumes we retain to third parties. Typically, our POP arrangements also include a fee-based component. In many cases, we provide services under contracts that contain a combination of the arrangements described above. When fees are charged (in addition to commodities received) under POP with fee contracts, we record such fees as service revenue on the Consolidated Statements of Income. The terms of our contracts vary based on natural gas quality conditions, the competitive environment when the contracts are signed and customer requirements.
Cost of Sales and Fuel	Cost of Sales and Fuel - Cost of sales and fuel primarily includes (i) the cost of purchased commodities, including NGLs, natural gas and condensate, (ii) fees incurred for third-party transportation, fractionation and storage of commodities, and (iii) fuel and power costs incurred to operate our own facilities that gather, process, transport and store commodities.
Operations and Maintenance	Operations and Maintenance - Operations and maintenance primarily includes (i) payroll and benefit costs, (ii) third-party costs for operations, maintenance and integrity management, regulatory compliance and environmental and safety, and (iii) other business related service costs.
Accounts Receivable	Accounts Receivable - Accounts receivable represent valid claims against nonaffiliated customers for products sold or services rendered, net of allowances for doubtful accounts. We assess the creditworthiness of our counterparties on an ongoing basis and require security, including prepayments and other forms of collateral, when appropriate. Outstanding customer receivables are reviewed regularly for possible nonpayment indicators, and allowances for doubtful accounts are recorded based upon management’s estimate of collectability at each balance sheet date. At December 31, 2015 and 2014 , our allowance for doubtful accounts was not material.
Inventory	Inventory - The values of current natural gas and NGLs in storage are determined using the lower of weighted-average cost or market method. Noncurrent natural gas and NGLs are classified as property and valued at cost. Materials and supplies are valued at average cost.
Commodity Imbalances	Commodity Imbalances - Commodity imbalances represent amounts payable or receivable for NGL exchange contracts and natural gas pipeline imbalances and are valued at market prices. Under the majority of our NGL exchange agreements, we physically receive volumes of unfractionated NGLs, including the risk of loss and legal title to such volumes, from the exchange counterparty. In turn, we deliver NGL products back to the customer and charge them gathering and fractionation fees. To the extent that the volumes we receive under such agreements differ from those we deliver, we record a net exchange receivable or payable position with the counterparties. These net exchange receivables and payables are settled with movements of NGL products rather than with cash. Natural gas pipeline imbalances are settled in cash or in-kind, subject to the terms of the pipelines’ tariffs or by agreement.
Derivatives and Risk Management	Derivatives and Risk Management - We utilize derivatives to reduce our market-risk exposure to commodity price and interest-rate fluctuations and to achieve more predictable cash flows. 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. See Notes C and D for more discussion of our fair value measurements and risk-management and hedging activities using derivatives.
Property, Plant and Equipment	Property, Plant and Equipment - Our properties are stated at cost, including AFUDC. Generally, the cost of regulated property retired or sold, plus removal costs, less salvage, is charged to accumulated depreciation. Gains and losses from sales or transfers of nonregulated properties or an entire operating unit or system of our regulated properties are recognized in income. Maintenance and repairs are charged directly to expense. The interest portion of AFUDC represents the cost of borrowed funds used to finance construction activities. We capitalize interest costs during the construction or upgrade of qualifying assets. Capitalized interest is recorded as a reduction to interest expense. The equity portion of AFUDC represents the capitalization of the estimated average cost of equity used during the construction of major projects and is recorded in the cost of our regulated properties and as a credit to the allowance for equity funds used during construction. Our properties are depreciated using the straight-line method over their estimated useful lives. Generally, we apply composite depreciation rates to functional groups of property having similar economic circumstances. We periodically conduct depreciation studies to assess the economic lives of our assets. For our regulated assets, these depreciation studies are completed as a part of our rate proceedings or tariff filings, and the changes in economic lives, if applicable, are implemented prospectively when the new rates are billed. For our nonregulated assets, if it is determined that the estimated economic life changes, the changes are made prospectively. Changes in the estimated economic lives of our property, plant and equipment could have a material effect on our financial position or results of operations. Property, plant and equipment on our Consolidated Balance Sheets includes construction work in process for capital projects that have not yet been placed in service and therefore are not being depreciated. Assets are transferred out of construction work in process when they are substantially complete and ready for their intended use. See Note E for disclosures of our property, plant and equipment.
Impairment of Goodwill and Long-Lived Assets, including Intangible Assets	Impairment of Goodwill and Long-Lived Assets, Including Intangible Assets - We assess our goodwill for impairment at least annually on July 1, unless events or changes in circumstances indicate an impairment may have occurred before that time. At July 1, 2015, due to the current commodity price environment, we elected to perform a quantitative assessment, or Step 1 analysis, to test our goodwill for impairment. The assessment included our commodity price assumptions, expected contractual terms, anticipated operating costs and volume estimates. Our goodwill impairment analysis performed as of July 1, 2015, did not result in an impairment charge nor did our analysis reflect any reporting units at risk. In each reporting unit, the fair value substantially exceeded the carrying value. At December 31, 2015, we performed a qualitative review given the decline in commodity prices and our common unit price since our assessment as of July 1, 2015, and determined that no event has occurred indicating that the implied fair value of each of our reporting units is less than the carrying value of its net assets. As part of our impairment test, we may first assess qualitative factors (including macroeconomic conditions, industry and market considerations, cost factors and overall financial performance) to determine whether it is more likely than not that the fair value of each of our reporting units is less than its carrying amount. If further testing is necessary or a quantitative test is elected, we perform a two-step impairment test for goodwill. In the first step, an initial assessment is made by comparing the fair value of a reporting unit with its book value, including goodwill. If the fair value is less than the book value, an impairment is indicated, and we must perform a second test to measure the amount of the impairment. In the second test, we calculate the implied fair value of the goodwill by deducting the fair value of all tangible and intangible net assets of the reporting unit from the fair value determined in step one of the assessment. If the carrying value of the goodwill exceeds the implied fair value of the goodwill, we will record an impairment charge. To estimate the fair value of our reporting units, we use two generally accepted valuation approaches, an income approach and a market approach, using assumptions consistent with a market participant’s perspective. Under the income approach, we use anticipated cash flows over a period of years plus a terminal value and discount these amounts to their present value using appropriate discount rates. Under the market approach, we apply EBITDA multiples to forecasted EBITDA. The multiples used are consistent with historical asset transactions. The forecasted cash flows are based on average forecasted cash flows for a reporting unit over a period of years. We assess our long-lived assets, including intangible assets with finite useful lives, for impairment whenever events or changes in circumstances indicate that an asset’s carrying amount may not be recoverable. An impairment is indicated if the carrying amount of a long-lived asset exceeds the sum of the undiscounted future cash flows expected to result from the use and eventual disposition of the asset. If an impairment is indicated, we record an impairment loss equal to the difference between the carrying value and the fair value of the long-lived asset. For the investments we account for under the equity method, the impairment test considers whether the fair value of the equity investment as a whole, not the underlying net assets, has declined and whether that decline is other than temporary. Therefore, we periodically reevaluate the amount at which we carry our equity-method investments to determine whether current events or circumstances warrant adjustments to our carrying value. See Notes E , F and M for our long-lived assets, goodwill and intangible assets and investments in unconsolidated affiliates disclosures.
Regulation	Regulation - Our intrastate natural gas transmission and natural gas liquids pipelines are subject to the rate regulation and accounting requirements of the OCC, KCC, RRC and various municipalities in Texas. Our interstate natural gas and natural gas liquids pipelines are subject to regulation by the FERC. In Kansas and Texas, natural gas storage may be regulated by the state and the FERC for certain types of services. Accordingly, portions of our Natural Gas Liquids and Natural Gas Pipelines segments follow the accounting and reporting guidance for regulated operations. During the rate-making process for certain of our assets, regulatory authorities set the framework for what we can charge customers for our services and establish the manner that our costs are accounted for, including allowing us to defer recognition of certain costs and permitting recovery of the amounts through rates over time as opposed to expensing such costs as incurred. Certain examples of types of regulatory guidance include costs for fuel and losses, acquisition costs, contributions in aid of construction, charges for depreciation, and gains or losses on disposition of assets. This allows us to stabilize rates over time rather than passing such costs on to the customer for immediate recovery. Actions by regulatory authorities could have an effect on the amount recovered from rate payers. Any difference in the amount recoverable and the amount deferred is recorded as income or expense at the time of the regulatory action. A write-off of regulatory assets and costs not recovered may be required if all or a portion of the regulated operations have rates that are no longer: • established by independent, third-party regulators; • designed to recover the specific entity’s costs of providing regulated services; and • set at levels that will recover our costs when considering the demand and competition for our services. At December 31, 2015 and 2014 , we recorded regulatory assets of approximately $5.8 million and $6.1 million , respectively, which are currently being recovered and are expected to be recovered from our customers. Regulatory assets are being recovered as a result of approved rate proceedings over varying time periods up to 40 years. These assets are reflected in other assets on our Consolidated Balance Sheets.
Income Taxes	Income Taxes - We are not a taxable entity for federal income tax purposes. As such, we do not directly pay federal income tax. Our taxable income or loss, which may vary substantially from the net income or loss reported in our Consolidated Statements of Income, is included in the federal income tax returns of each partner. The aggregate difference in the basis of our net assets for financial and income tax purposes cannot be readily determined, as we do not have access to all information about each partner’s tax attributes related to us. Our corporate subsidiaries are required to pay federal and state income taxes. Deferred income taxes are provided for the difference between the financial statement and income tax basis of assets and liabilities and carryforward items based on income tax laws and rates existing at the time the temporary differences are expected to reverse. Generally, the effect of a change in tax rates on deferred tax assets and liabilities is recognized in income in the period that includes the enactment date of the rate change. For regulated companies, the effect on deferred tax assets and liabilities of a change in tax rates is recorded as regulatory assets and regulatory liabilities in the period that includes the enactment date, if, as a result of an action by a regulator, it is probable that the effect of the change in tax rates will be recovered from or returned to customers through future rates. We utilize a more-likely-than-not recognition threshold and measurement attribute for the financial statement recognition and measurement of a tax position that is taken or expected to be taken in a tax return. We reflect penalties and interest as part of income tax expense as they become applicable for tax provisions that do not meet the more-likely-than-not recognition threshold and measurement attribute. During 2015, 2014 and 2013 , our tax positions did not require an establishment of a material reserve. We file numerous consolidated and separate income tax returns with federal tax authorities of the United States along with the tax authorities of several states. There are no United States federal audits or statute waivers at this time. See Note L for additional discussion of income taxes.
Asset Retirement Obligations	Asset Retirement Obligations - Asset retirement obligations represent legal obligations associated with the retirement of long-lived assets that result from the acquisition, construction, development and/or normal use of the asset. Certain of our natural gas gathering and processing facilities, and our natural gas liquids and pipeline facilities are subject to agreements or regulations that give rise to our asset retirement obligations for removal or other disposition costs associated with retiring the assets in place upon the discontinued use of the assets. We recognize the fair value of a liability for an asset retirement obligation in the period when it is incurred if a reasonable estimate of the fair value can be made. We are not able to estimate reasonably the fair value of the asset retirement obligations for portions of our assets, primarily certain pipeline assets, because the settlement dates are indeterminable given our expected continued use of the assets with proper maintenance. We expect our pipeline assets, for which we are unable to estimate reasonably the fair value of the asset retirement obligation, will continue in operation as long as supply and demand for natural gas and natural gas liquids exists. Based on the widespread use of natural gas for heating and cooking activities for residential users and electric-power generation for commercial users, as well as use of natural gas liquids by the petrochemical industry, we expect supply and demand to exist for the foreseeable future. For our assets that we are able to make an estimate, the fair value of the liability is added to the carrying amount of the associated asset, and this additional carrying amount is depreciated over the life of the asset. The liability is accreted at the end of each period through charges to operating expense. If the obligation is settled for an amount other than the carrying amount of the liability, we will recognize a gain or loss on settlement. The depreciation and accretion expense are immaterial to our consolidated financial statements. In accordance with long-standing regulatory treatment, we collect, through rates, the estimated costs of removal on certain regulated properties through depreciation expense, with a corresponding credit to accumulated depreciation and amortization. These removal costs collected through rates include legal and nonlegal removal obligations; however, the amounts collected in excess of the asset removal costs incurred are accounted for as a regulatory liability for financial reporting purposes. Historically, the regulatory authorities that have jurisdiction over our regulated operations have not required us to quantify this amount; rather, these costs are addressed prospectively in depreciation rates and are set in each general rate order. We have made an estimate of our regulatory liability using current rates since the last general rate order in each of our jurisdictions; however, for financial reporting purposes, significant uncertainty exists regarding the ultimate disposition of this regulatory liability pending, among other issues, clarification of regulatory intent. We continue to monitor regulatory requirements, and the liability may be adjusted as more information is obtained.
Contingencies	Contingencies - Our accounting for contingencies covers a variety of business activities, including contingencies for legal and environmental exposures. We accrue these contingencies when our assessments indicate that it is probable that a liability has been incurred or an asset will not be recovered and an amount can be estimated reasonably. We expense legal fees as incurred and base our legal liability estimates on currently available facts and our estimates of the ultimate outcome or resolution. Accruals for estimated losses from environmental remediation obligations generally are recognized no later than completion of a remediation feasibility study. Recoveries of environmental remediation costs from other parties are recorded as assets when their receipt is deemed probable. Our expenditures for environmental evaluation, mitigation, remediation and compliance to date have not been significant in relation to our financial position or results of operations, and our expenditures related to environmental matters had no material effect on earnings or cash flows during 2015, 2014 and 2013 . Actual results may differ from our estimates resulting in an impact, positive or negative, on earnings. See Note O for additional discussion of contingencies.
Accounting Standards Update 2015-17 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements	In November 2015, the FASB issued ASU 2015-17, “Income Taxes (Topic 740): Balance Sheet Classification of Deferred Taxes,” which simplifies the presentation and requires that deferred tax liabilities and assets be classified as noncurrent in the balance sheet. This guidance is effective for public companies for annual periods beginning after December 15, 2016, and interim periods within those annual periods. Earlier application is permitted as of the beginning of an interim or annual reporting period. We elected to adopt this guidance beginning in the fourth quarter 2015. Prior periods were not retrospectively adjusted. The impact of adopting this guidance was not material. See Note L for additional disclosures.
Accounting Standards Update 2015-03 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements	In March 2015, the FASB issued ASU 2015-03, “Interest - Imputation of Interest (Subtopic 835-30): Simplifying the Presentation of Debt Issuance Costs,” which requires that debt issuance costs related to a recognized debt liability be presented in the balance sheet as a direct deduction from the carrying amount of that debt liability, consistent with debt discounts. In August 2015, the FASB issued ASU 2015-15, “Interest - Imputation of Interest (Subtopic 835-30): Presentation and Subsequent Measurement of Debt Issuance Costs Associated with Line-of-Credit Arrangements - Amendments to SEC Paragraphs Pursuant to Staff Announcement at June 18, 2015 EITF Meeting,” which amended the SEC paragraphs of ASC Subtopic 835-30 to include the language from the SEC Staff Announcement indicating that the SEC would not object to presenting deferred debt issuance costs related to line-of-credit agreements as assets and subsequently amortizing the deferred debt issuance costs ratably over the term of the agreement. This guidance is effective for public companies for fiscal years beginning after December 15, 2015, with early adoption permitted. We elected to adopt this guidance beginning in the second quarter 2015. Retrospective adjustment of prior periods presented was required. Therefore, the December 31, 2014, balance sheet was recast to reclassify $34.1 million of debt issuance costs from other assets to long-term debt. See Note H for additional disclosures.
Accounting Standards Update 2014-08 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements	In April 2014, the FASB issued ASU 2014-08, “Presentation of Financial Statements (Topic 205) and Property, Plant, and Equipment (Topic 360): Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity,” which alters the definition of a discontinued operation to include only asset disposals that represent a strategic shift with a major effect on an entity’s operations and financial results. The amendment also requires more extensive disclosures about a discontinued operation’s assets, liabilities, income, expenses and cash flows. We adopted this guidance beginning in the first quarter 2015, and it could impact us in the future if we dispose of any individually significant components.
Accounting Standards Update 2016-01 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements	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 business entities 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 are evaluating the impact on us.
Accounting Standards Update 2015-16 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements	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 is effective for public companies for fiscal years beginning after December 15, 2015. We expect to adopt this guidance in the first quarter 2016, and it could impact us in the future if we complete any acquisitions with subsequent measurement period adjustments.
Accounting Standards Update 2015-11 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements	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 2015-05 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements	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 not account for the arrangement as a service contract. This guidance is effective for public companies for fiscal years beginning after December 15, 2015. We expect to adopt this guidance in the first quarter 2016, and we do not expect it to materially impact us.
Accounting Standards Update 2015-02 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements	In February 2015, the FASB issued ASU 2015-02, “Consolidation (Topic 810): Amendments to the Consolidation Analysis,” which eliminates the presumption that a general partner should consolidate a limited partnership. It also modifies the evaluation of whether limited partnerships are variable interest entities or voting interest entities and adds requirements that limited partnerships must meet to qualify as voting interest entities. This guidance is effective for public companies for fiscal years beginning after December 15, 2015. We expect to adopt this guidance in the first quarter 2016, and we are evaluating the impact on us.
Accounting Standards Update 2014-15 [Member]
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
New Accounting Pronouncements	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	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. We expect to adopt this guidance beginning in the first quarter 2018, and we are evaluating the impact on us.

ACQUISITIONS ACQUISITIONS (Poli

ACQUISITIONS ACQUISITIONS (Policies)	12 Months Ended
	Dec. 31, 2015
Sage Creek Acquisition [Member]
Business Acquisition [Line Items]
Business Combinations Policy [Policy Text Block]	This acquisition was accounted for as a business combination. The excess of cost over those fair values was recorded as goodwill.
West Texas LPG Acquisition [Member]
Business Acquisition [Line Items]
Business Combinations Policy [Policy Text Block]	We accounted for the West Texas LPG acquisition as a business combination which, among other things, requires assets acquired and liabilities assumed to be measured at their acquisition-date fair values.

LONG-TERM DEBT LONG-TERM DEBT (

LONG-TERM DEBT LONG-TERM DEBT (Policies)	12 Months Ended
	Dec. 31, 2015
Debt Instrument [Line Items]
Debt Policy	We amortize premiums, discounts and expenses incurred in connection with the issuance of long-term debt consistent with the terms of the respective debt instrument.

EQUITY EQUITY (Policies)

EQUITY EQUITY (Policies)	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
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 31

LIMITED PARTNERS' NET INCOME PER UNIT LIMITED PARTNERS' NET INCOME PER UNIT (Policies)	12 Months Ended
	Dec. 31, 2015
Earnings Per Share, Diluted, by Common Class, Including Two Class Method [Line Items]
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 amount of incentive distributions allocated to our general partner totaled $382.8 million , $326.0 million and $259.5 million for 2015, 2014 and 2013 , respectively. 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 I .

RELATED-PARTY TRANSACTIONS Rela

RELATED-PARTY TRANSACTIONS Related Party Transactions (Policies)	12 Months Ended
	Dec. 31, 2015
Related Party Transaction [Line Items]
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. Beginning in the second quarter 2014, ONEOK allocates substantially all of its general overhead costs to us as a result of ONEOK’s separation of its natural gas distribution business and the wind down of its energy services business in the first quarter 2014. For the first quarter 2014 and the year ended December 31, 2013, it is not practicable to determine what these general overhead costs would have been on a stand-alone basis. All costs directly charged or allocated to us are included in our Consolidated Statements of Income.

SEGMENTS SEGMENTS (Policies)

SEGMENTS SEGMENTS (Policies)	12 Months Ended
	Dec. 31, 2015
Segment Reporting [Abstract]
Segment Accounting Policy [Text Block]	We evaluate performance based principally on each segment’s operating income and equity in net earnings. The accounting policies of the segments are described in Note A . As a result of ONEOK’s separation of its natural gas distribution business into a stand-alone publicly traded company called ONE Gas on January 31, 2014, transactions with ONE Gas subsequent to the separation are reflected as sales to unaffiliated customers.

ACQUISITIONS ACQUISITIONS (Tabl

ACQUISITIONS ACQUISITIONS (Tables)	12 Months Ended
	Dec. 31, 2015
Sage Creek Acquisition [Member]
Business Acquisition [Line Items]
Schedule of Purchase Price Allocation [Table Text Block]	The purchase price and assessment of the fair value of the assets acquired were as follows: Natural Gas Gathering and Processing Natural Gas Liquids Total Property, plant and equipment ( Thousands of dollars ) Gathering pipelines and related equipment $ 41,129 $ 18,045 $ 59,174 Processing and fractionation and related equipment 50,595 — 50,595 General plant and other 120 — 120 Intangible assets 40,000 63,000 103,000 Identifiable assets acquired 131,844 81,045 212,889 Goodwill 20,000 72,000 92,000 Total purchase price $ 151,844 $ 153,045 $ 304,889
West Texas LPG Acquisition [Member]
Business Acquisition [Line Items]
Schedule of Purchase Price Allocation [Table Text Block]	The final purchase price allocation and assessment of the fair value of the assets acquired as of the acquisition date were as follows: ( Thousands of dollars ) Cash $ 13,839 Accounts receivable 9,132 Other current assets 3,369 Property, plant and equipment Regulated 812,716 Nonregulated 157,643 Total property, plant and equipment 970,359 Total fair value of assets acquired 996,699 Accounts payable (8,621 ) Other liabilities (10,867 ) Total fair value of liabilities acquired (19,488 ) Less: Fair value of noncontrolling interest (162,438 ) Net assets acquired 814,773 Less: Cash received (13,839 ) Net cash paid for acquisition $ 800,934

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	12 Months Ended
	Dec. 31, 2015
Fair Value Disclosures [Abstract]
Recurring Fair Value Measurements	Recurring Fair Value Measurements - The following tables set forth our recurring fair value measurements for the periods indicated: 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) - Our 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 had $34.4 million of cash held from various counterparties and no cash collateral posted. (b) - Included in other current assets or other current liabilities in our Consolidated Balance Sheets. December 31, 2014 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net (b) ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 42,880 $ — $ 354 $ 43,234 $ (25,979 ) $ 17,255 Physical contracts — — 9,922 9,922 — 9,922 Interest-rate contracts — 2,288 — 2,288 — 2,288 Total derivative assets $ 42,880 $ 2,288 $ 10,276 $ 55,444 $ (25,979 ) $ 29,465 Derivative liabilities Commodity contracts Financial contracts $ (169 ) $ — $ (968 ) $ (1,137 ) $ 1,137 $ — Physical contracts — — (23 ) (23 ) — (23 ) Interest-rate contracts — (44,843 ) — (44,843 ) — (44,843 ) Total derivative liabilities $ (169 ) $ (44,843 ) $ (991 ) $ (46,003 ) $ 1,137 $ (44,866 ) (a) - Our 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, 2014 , we had $24.8 million of cash held from various counterparties and no cash collateral posted. (b) - Included in other current assets, other 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: Years Ended December 31, Derivative Assets (Liabilities) 2015 2014 ( Thousands of dollars ) Net assets (liabilities) at beginning of period $ 9,285 $ (782 ) Total realized/unrealized gains (losses): Included in earnings (a) 216 (927 ) Included in other comprehensive income (loss) (2,170 ) 7,260 Settlements — 3,734 Net assets (liabilities) at end of period $ 7,331 $ 9,285 (a) - Included in commodity sales revenues in our Consolidated Statements of Income.

RISK MANAGEMENT AND HEDGING A36

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES (Tables)	12 Months Ended
	Dec. 31, 2015
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Schedule of Derivative Instruments in Statement of Financial Position	Fair Values of Derivative Instruments - The following table sets forth the fair values of our derivative instruments for the periods indicated: December 31, 2015 December 31, 2014 Assets (a) (Liabilities) (a) Assets (b) (Liabilities) (b) ( Thousands of dollars ) Derivatives designated as hedging instruments Commodity contracts Financial contracts $ 39,255 $ (1,440 ) $ 43,234 $ (1,137 ) Physical contracts 3,591 — 9,922 — Interest-rate contracts — (9,936 ) 2,288 (44,843 ) Total derivatives designated as hedging instruments 42,846 (11,376 ) 55,444 (45,980 ) Derivatives not designated as hedging instruments Commodity contracts Financial contracts 6,919 (6,586 ) — — Physical contracts — — — (23 ) Total derivatives not designated as hedging instruments 6,919 (6,586 ) — (23 ) Total derivatives $ 49,765 $ (17,962 ) $ 55,444 $ (46,003 ) (a) - Included on a net basis in other current assets or other current liabilities in our Consolidated Balance Sheets. (b) - Included on a net basis in other current assets, other assets or other current liabilities in our Consolidated Balance Sheets.
Schedule of Notional Quantities for Derivative Instruments	Notional Quantities for Derivative Instruments - The following table sets forth the notional quantities for derivative instruments held for the periods indicated: December 31, 2015 December 31, 2014 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 — (27.1 ) — (41.2 ) -Crude oil and NGLs ( MMBbl ) Futures, forwards and swaps — (2.3 ) — (0.5 ) Basis -Natural gas ( Bcf ) Futures and swaps — (27.1 ) — (41.2 ) Interest-rate contracts ( Millions of dollars ) Forward-starting swaps $ 400.0 $ — $ 900.0 $ — Derivatives not designated as hedging instruments: Fixed price -Crude oil and NGLs ( MMBbl ) Futures, forwards and swaps 0.6 (0.6 ) — —
Schedule of Cash Flow Hedges in Other Comprehensive Income (Loss)	The following table sets forth the unrealized effect of cash flow hedges recognized in other comprehensive income (loss) for the periods indicated: Derivatives in Cash Flow Hedging Relationships Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Commodity contracts $ 70,065 $ 32,354 $ (14,475 ) Interest-rate contracts (22,565 ) (96,993 ) 46,616 Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives(effective portion) $ 47,500 $ (64,639 ) $ 32,141
Schedule of Derivative Instruments, Gain (loss) of Statement of Financial Performance	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) Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Commodity contracts Commodity sales revenues $ 81,089 $ (21,052 ) $ 1,689 Interest-rate contracts Interest expense (14,055 ) (10,601 ) (10,033 ) Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income on derivatives (effective portion) $ 67,034 $ (31,653 ) $ (8,344 )

PROPERTY, PLANT AND EQUIPMENT (

PROPERTY, PLANT AND EQUIPMENT (Tables)	12 Months Ended
	Dec. 31, 2015
Property, Plant and Equipment [Abstract]
Property, Plant and Equipment by Property Type	The following table sets forth our property, plant and equipment by property type, for the periods indicated: Estimated Useful Lives (Years) December 31, December 31, ( Thousands of dollars ) Nonregulated Gathering pipelines and related equipment 5 to 40 $ 2,961,388 $ 2,449,343 Processing and fractionation and related equipment 3 to 40 3,627,062 2,880,572 Storage and related equipment 5 to 54 456,437 478,276 Transmission pipelines and related equipment 5 to 54 416,391 518,585 General plant and other 2 to 60 186,358 142,276 Construction work in process — 690,179 1,233,808 Regulated Storage and related equipment 5 to 54 76,468 115,799 Natural gas transmission pipelines and related equipment 5 to 77 1,507,220 1,478,035 Natural gas liquids transmission pipelines and related equipment 5 to 88 4,208,121 3,822,799 General plant and other 2 to 54 94,461 63,424 Construction work in process — 83,461 194,700 Property, plant and equipment 14,307,546 13,377,617 Accumulated depreciation and amortization - nonregulated (1,219,435 ) (1,123,261 ) Accumulated depreciation and amortization - regulated (831,320 ) (718,823 ) Net property, plant and equipment $ 12,256,791 $ 11,535,533
Average Depreciation Rates for Regulated Property	The average depreciation rates for our regulated property are set forth, by segment, in the following table for the periods indicated: Years Ended December 31, 2015 2014 2013 Natural Gas Liquids 1.9% 2.0% 2.0% Natural Gas Pipelines 2.1% 2.1% 2.2%

GOODWILL AND INTANGIBLE ASSETS

GOODWILL AND INTANGIBLE ASSETS (Tables)	12 Months Ended
	Dec. 31, 2015
Goodwill and Intangible Assets Disclosure [Abstract]
Goodwill by Segment	Goodwill - The following table sets forth our goodwill, by segment, for the periods indicated: December 31, 2015 December 31, 2014 ( Thousands of dollars ) Natural Gas Gathering and Processing $ 112,141 $ 112,141 Natural Gas Liquids 247,566 247,566 Natural Gas Pipelines 129,011 129,011 Total goodwill $ 488,718 $ 488,718
Gross Carrying Amount and Accumulated Amortization of Intangible Assets	The following table reflects the gross carrying amount and accumulated amortization of intangible assets for the periods presented: December 31, December 31, ( Thousands of dollars ) Gross intangible assets $ 426,068 $ 411,650 Accumulated amortization (89,909 ) (78,010 ) Net intangible assets $ 336,159 $ 333,640

LONG-TERM DEBT (Tables)

LONG-TERM DEBT (Tables)	12 Months Ended
	Dec. 31, 2015
Long-term Debt, Unclassified [Abstract]
Long-term debt	The following table sets forth our long-term debt for the periods indicated: December 31, December 31, ( Thousands of dollars ) ONEOK Partners $650,000 at 3.25% due 2016 $ 650,000 $ 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 $500,000 at 8.625% due 2019 500,000 500,000 $300,000 at 3.8% due 2020 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 — $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 7.88% due 2022 51,907 59,557 Total long-term notes payable 6,851,907 6,059,557 Unamortized debt issuance costs and discounts (48,945 ) (47,675 ) Current maturities (107,650 ) (7,650 ) Long-term debt $ 6,695,312 $ 6,004,232
Aggregate maturities of long-term debt outstanding	The aggregate maturities of long-term debt outstanding as of December 31, 2015, for the years 2016 through 2020 are shown below: ONEOK Partners Guardian Pipeline Total ( Millions of dollars ) 2016 $ 1,100.0 $ 7.7 $ 1,107.7 2017 $ 400.0 $ 7.7 $ 407.7 2018 $ 425.0 $ 7.7 $ 432.7 2019 $ 500.0 $ 7.7 $ 507.7 2020 $ 300.0 $ 7.7 $ 307.7

EQUITY (Tables)

EQUITY (Tables)	12 Months Ended
	Dec. 31, 2015
Equity [Abstract]
Quarterly cash distribution declared and paid on common and Class B units	Cash Distributions - The following table sets forth the quarterly cash distribution declared and paid on each of our common and Class B units during the periods indicated: Declared for Quarter Ending Distribution Per Unit Date Declared Date Paid December 31, 2015 $ 0.790 January 21, 2016 February 12, 2016 September 30, 2015 $ 0.790 October 21, 2015 November 13, 2015 June 30, 2015 $ 0.790 July 23, 2015 August 14, 2015 March 31, 2015 $ 0.790 April 16, 2015 May 15, 2015 December 31, 2014 $ 0.790 January 15, 2015 February 13, 2015 September 30, 2014 $ 0.775 October 23, 2014 November 14, 2014 June 30, 2014 $ 0.760 July 25, 2014 August 14, 2014 March 31, 2014 $ 0.745 April 18, 2014 May 15, 2014 December 31, 2013 $ 0.730 January 16, 2014 February 14, 2014 September 30, 2013 $ 0.725 October 23, 2013 November 14, 2013 June 30, 2013 $ 0.720 July 25, 2013 August 15, 2013 March 31, 2013 $ 0.715 April 18, 2013 May 15, 2013 December 31, 2012 $ 0.710 January 17, 2013 February 14, 2013
Schedule of distributions made to general or limited partner	The following table shows our distributions paid during the periods indicated: Years Ended December 31, 2015 2014 2013 ( Thousands, except per unit amounts ) Distribution per unit $ 3.16 $ 3.01 $ 2.87 General partner distributions $ 24,610 $ 21,044 $ 18,193 Incentive distributions 371,500 304,999 251,664 Distributions to general partner 396,110 326,043 269,857 Limited partner distributions to ONEOK 310,230 279,292 266,302 Limited partner distributions to other unitholders 524,135 446,910 373,554 Total distributions paid $ 1,230,475 $ 1,052,245 $ 909,713
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: Years Ended December 31, 2015 2014 2013 ( Thousands, except per unit amounts ) Distribution per unit $ 3.16 $ 3.07 $ 2.89 General partner distributions $ 25,356 $ 22,109 $ 18,625 Incentive distributions 382,759 326,022 259,466 Distributions to general partner 408,115 348,131 278,091 Limited partner distributions to ONEOK 327,250 284,860 268,157 Limited partner distributions to other unitholders 532,405 472,466 384,988 Total distributions declared $ 1,267,770 $ 1,105,457 $ 931,236

ACCUMULATED OTHER COMPREHENSI41

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Tables)	12 Months Ended
	Dec. 31, 2015
Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block]	The following table sets forth the balance in accumulated other comprehensive income (loss) for the periods indicated: Accumulated Other Comprehensive Loss (a) ( Thousands of dollars ) January 1, 2014 $ (58,837 ) Other comprehensive income (loss) before reclassifications (64,639 ) Amounts reclassified from accumulated other comprehensive income (loss) 31,653 Net current-period other comprehensive income (loss) attributable to ONEOK Partners (32,986 ) December 31, 2014 (91,823 ) Other comprehensive income (loss) before reclassifications 45,575 Amounts reclassified from accumulated other comprehensive income (loss) (67,034 ) Net current-period other comprehensive income (loss) attributable to ONEOK Partners (21,459 ) December 31, 2015 $ (113,282 ) (a) All amounts are attributable to unrealized gains (losses) in risk-management assets/liabilities.
Disclosure of Reclassification Amount [Text Block]	The following table sets forth the effect of reclassifications from accumulated other comprehensive income (loss) in our Consolidated Statements of Income for the periods indicated: Details about Accumulated Other Comprehensive Income (Loss) Components Year Ended December 31, Affected Line Item in the Consolidated Statements of Income 2015 2014 2013 ( Thousands of dollars ) Unrealized (gains) losses on risk-management assets/liabilities Commodity contracts $ (81,089 ) $ 21,052 $ (1,689 ) Commodity sales revenues Interest-rate contracts 14,055 10,601 10,033 Interest expense Total reclassifications for the period attributable to ONEOK Partners $ (67,034 ) $ 31,653 $ 8,344 Net income attributable to ONEOK Partners

INCOME TAXES (Tables)

INCOME TAXES (Tables)	12 Months Ended
	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Reconciliation of Income Tax Provision	The following table sets forth our provision for income taxes for the periods indicated: Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Current income tax provision Federal $ — $ 59 $ 56 State (621 ) 1,777 5,358 Total current income tax provision (621 ) 1,836 5,414 Deferred income tax provision Federal 5,413 5,033 4,303 State (648 ) 5,799 1,141 Total deferred income tax provision 4,765 10,832 5,444 Total provision for income taxes $ 4,144 $ 12,668 $ 10,858
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]	The following table is a reconciliation of our income tax provision for the periods indicated: Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Income before income taxes $ 602,016 $ 924,003 $ 814,841 Less: Net income attributable to noncontrolling interests 8,330 1,037 357 Income attributable to ONEOK Partners, L.P. before income taxes 593,686 922,966 814,484 Federal statutory income tax rate 35.0 % 35.0 % 35.0 % Provision for federal income taxes 207,790 323,038 285,069 Partnership earnings not subject to tax (202,143 ) (318,021 ) (280,992 ) State income taxes, net of federal benefit (2,078 ) 7,576 6,095 State deferred tax rate change, net of valuation allowance 810 — — Other, net (235 ) 75 686 Income tax provision $ 4,144 $ 12,668 $ 10,858
Schedule of Deferred Tax Assets and Liabilities	The following table sets forth the tax effects of temporary differences that gave rise to significant portions of the deferred tax assets and liabilities for the periods indicated. Years Ended December 31, 2015 2014 ( Thousands of dollars ) Deferred tax assets Federal and state net operating loss $ 4,224 $ 3,179 Other 7 1,626 Total deferred tax assets 4,231 4,805 Deferred tax liabilities Excess of tax over book depreciation 67,265 61,120 Regulatory assets 49 1,962 Total deferred tax liabilities 67,314 63,082 Net deferred tax liabilities $ 63,083 $ 58,277

UNCONSOLIDATED AFFILIATES (Tabl

UNCONSOLIDATED AFFILIATES (Tables)	12 Months Ended
	Dec. 31, 2015
Schedule of Equity Method Investments [Line Items]
Schedule of Equity Method Investments	Investments in Unconsolidated Affiliates - The following table sets forth our investments in unconsolidated affiliates for the periods indicated: Net Ownership Interest December 31, December 31, ( Thousands of dollars ) Northern Border Pipeline 50% $ 363,231 $ 387,253 Overland Pass Pipeline Company 50% 459,354 466,977 Other Various 125,636 278,423 Investments in unconsolidated affiliates (a) $ 948,221 $ 1,132,653 (a) - Equity-method goodwill (Note A ) was $40.1 million and $170.9 million at December 31, 2015 and 2014 , respectively.
Summarized Financial Information Of Unconsolidated Affiliates [Member]
Schedule of Equity Method Investments [Line Items]
Schedule of Equity Method Investments	Unconsolidated Affiliates Financial Information - The following tables set forth summarized combined financial information of our unconsolidated affiliates for the periods indicated: December 31, December 31, ( Thousands of dollars ) Balance Sheet Current assets $ 149,439 $ 153,293 Property, plant and equipment, net $ 2,556,559 $ 2,440,714 Other noncurrent assets $ 23,722 $ 35,668 Current liabilities $ 211,037 $ 95,026 Long-term debt $ 425,521 $ 428,385 Other noncurrent liabilities $ 69,356 $ 73,767 Accumulated other comprehensive loss $ (5,669 ) $ (2,063 ) Owners’ equity $ 2,029,475 $ 2,034,560 Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Income Statement Operating revenues $ 524,496 $ 548,491 $ 528,665 Operating expenses (a) $ 304,930 $ 309,990 $ 256,292 Net income (a) $ 200,064 $ 214,410 $ 248,998 Distributions paid to us $ 155,918 $ 139,019 $ 137,498 (a) Includes long-lived asset impairment charges in 2015 and 2014.
Equity In Net Earnings From Investments [Member]
Schedule of Equity Method Investments [Line Items]
Schedule of Equity Method Investments	Equity in Net Earnings from Investments and Impairments - The following table sets forth our equity in net earnings from investments for the periods indicated: Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Northern Border Pipeline $ 66,941 $ 69,819 $ 65,046 Overland Pass Pipeline Company 37,783 25,906 20,461 Other 20,576 21,690 25,010 Equity in net earnings from investments $ 125,300 $ 117,415 $ 110,517 Impairment of equity investments $ (180,583 ) $ (76,412 ) $ —

RELATED-PARTY TRANSACTIONS (Tab

RELATED-PARTY TRANSACTIONS (Tables)	12 Months Ended
	Dec. 31, 2015
Related Party Transactions [Abstract]
Transactions with related parties	The following table sets forth the transactions with related parties for the periods indicated: Years Ended December 31, 2015 2014 2013 ( Thousands of dollars ) Revenues $ — $ 53,526 $ 340,743 Expenses Cost of sales and fuel $ — $ 10,835 $ 37,963 Operating expenses 368,346 330,541 265,448 Total expenses $ 368,346 $ 341,376 $ 303,411

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Tables)	12 Months Ended
	Dec. 31, 2015
Commitments and Contingencies Disclosure [Abstract]
Future Minimum Rental Payments for Firm Transportation and Storage Contracts	The following table sets forth our firm transportation and storage contract payments for our continuing operations for the periods indicated: Firm Transportation and Storage Contracts ( Millions of dollars ) 2016 $ 45.8 2017 42.1 2018 40.6 2019 36.2 2020 35.8 Thereafter 47.9 Total $ 248.4

SEGMENTS (Tables)

SEGMENTS (Tables)	12 Months Ended
	Dec. 31, 2015
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Selected Financial Information by Reportable Segment	Operating Segment Information - The following tables set forth certain selected financial information for our operating segments for the periods indicated: Year Ended December 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 $ 1,187,390 $ 6,248,002 $ 325,676 $ — $ 7,761,068 Intersegment revenues 649,726 331,697 6,771 (988,194 ) — Total revenues 1,837,116 6,579,699 332,447 (988,194 ) 7,761,068 Cost of sales and fuel (exclusive of items shown separately below) 1,265,617 5,328,256 34,481 (987,302 ) 5,641,052 Operating costs 272,418 314,505 105,720 (467 ) 692,176 Depreciation and amortization 150,008 158,709 43,479 — 352,196 Impairment of long-lived assets 73,681 9,992 — — 83,673 Gain (loss) on sale of assets 2,775 (939 ) 4,272 — 6,108 Operating income $ 78,167 $ 767,298 $ 153,039 $ (425 ) $ 998,079 Equity in net earnings from investments $ 17,863 $ 38,696 $ 68,741 $ — $ 125,300 Impairment of equity investments $ (180,583 ) $ — $ — $ — $ (180,583 ) Investments in unconsolidated affiliates $ 73,920 $ 482,672 $ 391,629 $ — $ 948,221 Total assets $ 5,123,450 $ 8,017,799 $ 1,844,401 $ (58,064 ) $ 14,927,586 Noncontrolling interests in consolidated subsidiaries $ 4,041 $ 160,084 $ — $ — $ 164,125 Capital expenditures $ 887,938 $ 226,135 $ 58,215 $ 13,835 $ 1,186,123 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $954.8 million , of which $770.1 million related to sales within the segment, cost of sales and fuel of $412.6 million and operating income of $306.9 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $266.9 million , cost of sales and fuel of $31.1 million and operating income of $103.7 million . Year Ended December 31, 2014 Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Other and Eliminations Total ( Thousands of dollars ) Sales to unaffiliated customers $ 1,478,729 $ 10,329,609 $ 329,801 $ — $ 12,138,139 Sales to affiliated customers 41,214 — 12,312 — 53,526 Intersegment revenues 1,447,665 215,772 8,343 (1,671,780 ) — Total revenues 2,967,608 10,545,381 350,456 (1,671,780 ) 12,191,665 Cost of sales and fuel (exclusive of items shown separately below) 2,305,723 9,435,296 21,935 (1,674,406 ) 10,088,548 Operating costs 257,658 296,402 111,037 4,560 669,657 Depreciation and amortization 123,847 124,071 43,318 — 291,236 Gain (loss) on sale of assets 219 (572 ) 6,786 166 6,599 Operating income $ 280,599 $ 689,040 $ 180,952 $ (1,768 ) $ 1,148,823 Equity in net earnings from investments $ 20,271 $ 27,326 $ 69,818 $ — $ 117,415 Impairment of equity investments $ (76,412 ) $ — $ — $ — $ (76,412 ) Investments in unconsolidated affiliates $ 254,818 $ 490,582 $ 387,253 $ — $ 1,132,653 Total assets $ 4,911,283 $ 8,143,575 $ 1,823,713 $ (278,171 ) $ 14,600,400 Noncontrolling interests in consolidated subsidiaries $ 4,251 $ 163,671 $ — $ 15 $ 167,937 Capital expenditures $ 898,896 $ 798,048 $ 42,991 $ 6,055 $ 1,745,990 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $695.9 million , of which $598.1 million related to sales within the segment, cost of sales and fuel of $309.4 million and operating income of $196.1 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $290.0 million , cost of sales and fuel of $47.7 million and operating income of $106.5 million . Year Ended December 31, 2013 Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Other and Eliminations Total ( Thousands of dollars ) Sales to unaffiliated customers $ 665,169 $ 10,644,117 $ 219,244 $ — $ 11,528,530 Sales to affiliated customers 238,600 — 102,143 — 340,743 Intersegment revenues 1,147,713 133,910 4,127 (1,285,750 ) — Total revenues 2,051,482 10,778,027 325,514 (1,285,750 ) 11,869,273 Cost of sales and fuel (exclusive of items shown separately below) 1,550,855 9,908,089 39,795 (1,276,526 ) 10,222,213 Operating costs 193,293 236,638 101,182 (9,600 ) 521,513 Depreciation and amortization 103,962 89,240 43,541 — 236,743 Loss on sale of assets 436 843 10,602 — 11,881 Operating income $ 203,808 $ 544,903 $ 151,598 $ 376 $ 900,685 Equity in net earnings from investments $ 23,493 $ 21,978 $ 65,046 $ — $ 110,517 Investments in unconsolidated affiliates $ 333,179 $ 491,856 $ 404,803 $ — $ 1,229,838 Total assets $ 3,949,813 $ 6,938,633 $ 1,817,445 $ 118,269 $ 12,824,160 Noncontrolling interests in consolidated subsidiaries $ 4,521 $ — $ — $ 15 $ 4,536 Capital expenditures $ 774,379 $ 1,128,345 $ 34,699 $ 1,903 $ 1,939,326 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $534.8 million , of which $449.9 million related to sales within the segment, cost of sales and fuel of $207.4 million and operating income of $190.5 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $246.9 million , cost of sales and fuel of $29.3 million and operating income of $90.5 million .

QUARTERLY FINANCIAL DATA (UNA47

QUARTERLY FINANCIAL DATA (UNAUDITED) (Tables)	12 Months Ended
	Dec. 31, 2015
Quarterly Financial Data [Abstract]
Quarterly Financial Data	Year Ended December 31, 2015 First Quarter Second Quarter Third Quarter Fourth Quarter ( Thousands of dollars, except per unit amounts ) Revenues $ 1,804,759 $ 2,127,507 $ 1,898,418 $ 1,930,384 Net income $ 147,032 $ 211,610 $ 229,665 $ 9,565 Net income attributable to ONEOK Partners, L.P. $ 145,594 $ 209,770 $ 226,961 $ 7,217 Limited partners’ per unit net income (loss) $ 0.21 $ 0.44 $ 0.45 $ (0.33 ) The fourth quarter 2015 includes noncash impairment charges of $264.3 million related to long-lived assets and equity investments. Year Ended December 31, 2014 First Quarter Second Quarter Third Quarter Fourth Quarter ( Thousands of dollars, except per unit amounts ) Revenues $ 3,162,303 $ 3,065,735 $ 3,119,369 $ 2,844,258 Net income $ 265,468 $ 214,511 $ 167,320 $ 264,036 Net income attributable to ONEOK Partners, L.P. $ 265,392 $ 214,434 $ 167,247 $ 263,225 Limited partners’ per unit net income $ 0.81 $ 0.54 $ 0.32 $ 0.67 The third quarter 2014 includes noncash impairment charges of $76.4 million related to equity investments.

SUPPLEMENTAL CONDENSED CONSOL48

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION (Tables)	12 Months Ended
	Dec. 31, 2015
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Consolidating Statements of Income	Condensed Consolidating Statements of Income Year Ended December 31, 2015 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ 6,098.3 $ — $ 6,098.3 Services — — 1,662.8 — 1,662.8 Total revenues — — 7,761.1 — 7,761.1 Cost of sales and fuel (exclusive of items shown separately below) — — 5,641.1 — 5,641.1 Impairment of long-lived assets — — 83.7 — 83.7 Operating expenses — — 1,044.3 — 1,044.3 Gain (loss) on sale of assets — — 6.1 — 6.1 Operating income — — 998.1 — 998.1 Equity in net earnings from investments 589.5 589.5 58.4 (1,112.1 ) 125.3 Impairment of equity investments — — (180.6 ) — (180.6 ) Other income (expense), net 371.0 371.0 (1.9 ) (742.0 ) (1.9 ) Interest expense (371.0 ) (371.0 ) (338.9 ) 742.0 (338.9 ) Income before income taxes 589.5 589.5 535.1 (1,112.1 ) 602.0 Income taxes — — (4.1 ) — (4.1 ) Net income 589.5 589.5 531.0 (1,112.1 ) 597.9 Less: Net income attributable to noncontrolling interests — — 8.4 — 8.4 Net income attributable to ONEOK Partners, L.P. $ 589.5 $ 589.5 $ 522.6 $ (1,112.1 ) $ 589.5 Year Ended December 31, 2014 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ 10,725.0 $ — $ 10,725.0 Services — — 1,466.7 — 1,466.7 Total revenues — — 12,191.7 — 12,191.7 Cost of sales and fuel (exclusive of items shown separately below) — — 10,088.6 — 10,088.6 Operating expenses — — 960.9 — 960.9 Gain (loss) on sale of assets — — 6.6 — 6.6 Operating income — — 1,148.8 — 1,148.8 Equity in net earnings from investments 910.3 910.3 47.6 (1,750.8 ) 117.4 Impairment of equity investments — — (76.4 ) — (76.4 ) Other income (expense), net 331.7 331.7 16.1 (663.4 ) 16.1 Interest expense,net (331.7 ) (331.7 ) (281.9 ) 663.4 (281.9 ) Income before income taxes 910.3 910.3 854.2 (1,750.8 ) 924.0 Income taxes — — (12.7 ) — (12.7 ) Net income 910.3 910.3 841.5 (1,750.8 ) 911.3 Less: Net income attributable to noncontrolling interests — — 1.0 — 1.0 Net income attributable to ONEOK Partners, L.P. $ 910.3 $ 910.3 $ 840.5 $ (1,750.8 ) $ 910.3 Year Ended December 31, 2013 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ 10,549.2 $ — $ 10,549.2 Services — — 1,320.1 — 1,320.1 Total revenues — — 11,869.3 — 11,869.3 Cost of sales and fuel (exclusive of items shown separately below) — — 10,222.2 — 10,222.2 Operating expenses — — 758.3 — 758.3 Gain (loss) on sale of assets — — 11.9 — 11.9 Operating income — — 900.7 — 900.7 Equity in net earnings from investments 803.6 803.6 45.5 (1,542.2 ) 110.5 Other income (expense), net 287.6 287.6 40.3 (575.2 ) 40.3 Interest expense (287.6 ) (287.6 ) (236.7 ) 575.2 (236.7 ) Income before income taxes 803.6 803.6 749.8 (1,542.2 ) 814.8 Income taxes — — (10.8 ) — (10.8 ) Net income 803.6 803.6 739.0 (1,542.2 ) 804.0 Less: Net income attributable to noncontrolling interests — — 0.4 — 0.4 Net income attributable to ONEOK Partners, L.P. $ 803.6 $ 803.6 $ 738.6 $ (1,542.2 ) $ 803.6
Condensed Consolidating Statements of Comprehensive Income	Condensed Consolidating Statements of Comprehensive Income Year Ended December 31, 2015 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 589.5 $ 589.5 $ 531.0 $ (1,112.1 ) $ 597.9 Other comprehensive income (loss) Unrealized gains (losses) on derivatives 45.6 68.1 68.1 (136.2 ) 45.6 Realized (gains) losses on derivatives recognized in net income (67.0 ) (81.1 ) (81.1 ) 162.2 (67.0 ) Total other comprehensive income (loss) (21.4 ) (13.0 ) (13.0 ) 26.0 (21.4 ) Comprehensive income 568.1 576.5 518.0 (1,086.1 ) 576.5 Less: Comprehensive income attributable to noncontrolling interests — — 8.4 — 8.4 Comprehensive income attributable to ONEOK Partners, L.P. $ 568.1 $ 576.5 $ 509.6 $ (1,086.1 ) $ 568.1 Year Ended December 31, 2014 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 910.3 $ 910.3 $ 841.5 $ (1,750.8 ) $ 911.3 Other comprehensive income (loss) Unrealized gains (losses) on derivatives (64.6 ) 32.4 32.4 (64.8 ) (64.6 ) Realized (gains) losses on derivatives recognized in net income 31.6 21.1 21.1 (42.2 ) 31.6 Total other comprehensive income (loss) (33.0 ) 53.5 53.5 (107.0 ) (33.0 ) Comprehensive income 877.3 963.8 895.0 (1,857.8 ) 878.3 Less: Comprehensive income attributable to noncontrolling interests — — 1.0 — 1.0 Comprehensive income attributable to ONEOK Partners, L.P. $ 877.3 $ 963.8 $ 894.0 $ (1,857.8 ) $ 877.3 Year Ended December 31, 2013 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 803.6 $ 803.6 $ 739.0 $ (1,542.2 ) $ 804.0 Other comprehensive income (loss) Unrealized gains (losses) on derivatives 32.1 (14.5 ) (14.5 ) 29.0 32.1 Realized (gains) losses on derivatives recognized in net income 8.4 (1.7 ) (1.7 ) 3.4 8.4 Total other comprehensive income (loss) 40.5 (16.2 ) (16.2 ) 32.4 40.5 Comprehensive income 844.1 787.4 722.8 (1,509.8 ) 844.5 Less: Comprehensive income attributable to noncontrolling interests — — 0.4 — 0.4 Comprehensive income attributable to ONEOK Partners, L.P. $ 844.1 $ 787.4 $ 722.4 $ (1,509.8 ) $ 844.1
Condensed Consolidating Balance Sheets	Condensed Consolidating Balance Sheets December 31, 2015 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 Materials and supplies — — 76.7 — 76.7 Other current assets 4.1 — 67.8 — 71.9 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 December 31, 2014 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total Assets ( Millions of dollars ) Current assets Cash and cash equivalents $ — $ 42.5 $ — $ — $ 42.5 Accounts receivable, net — — 735.8 — 735.8 Affiliate receivables — — 8.6 — 8.6 Natural gas and natural gas liquids in storage — — 134.1 — 134.1 Materials and supplies — — 55.8 — 55.8 Other current assets 1.9 — 107.3 — 109.2 Total current assets 1.9 42.5 1,041.6 — 1,086.0 Property, plant and equipment Property, plant and equipment — — 13,377.6 — 13,377.6 Accumulated depreciation and amortization — — 1,842.1 — 1,842.1 Net property, plant and equipment — — 11,535.5 — 11,535.5 Investments and other assets Intercompany notes receivable 8,843.3 7,579.0 — (16,422.3 ) — Other assets 4,250.1 5,469.8 1,590.3 (9,331.3 ) 1,978.9 Total investments and other assets 13,093.4 13,048.8 1,590.3 (25,753.6 ) 1,978.9 Total assets $ 13,095.3 $ 13,091.3 $ 14,167.4 $ (25,753.6 ) $ 14,600.4 Liabilities and equity Current liabilities Current maturities of long-term debt $ — $ — $ 7.7 $ — $ 7.7 Short-term borrowings 1,055.3 — — — 1,055.3 Accounts payable — — 874.7 — 874.7 Affiliate payables — — 36.1 — 36.1 Other current liabilities 136.8 — 225.5 — 362.3 Total current liabilities 1,192.1 — 1,144.0 — 2,336.1 Intercompany debt — 8,843.3 7,579.0 (16,422.3 ) — Long-term debt, excluding current maturities 5,952.4 — 51.9 — 6,004.3 Deferred credits and other liabilities — — 141.3 — 141.3 Commitments and contingencies Equity Equity excluding noncontrolling interests in consolidated subsidiaries 5,950.8 4,248.0 5,083.3 (9,331.3 ) 5,950.8 Noncontrolling interests in consolidated subsidiaries — — 167.9 — 167.9 Total equity 5,950.8 4,248.0 5,251.2 (9,331.3 ) 6,118.7 Total liabilities and equity $ 13,095.3 $ 13,091.3 $ 14,167.4 $ (25,753.6 ) $ 14,600.4
Condensed Consolidating Statements of Cash Flows	Condensed Consolidating Statements of Cash Flows Year Ended December 31, 2015 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 1,196.7 $ 66.9 $ 1,038.9 $ (1,230.5 ) $ 1,072.0 Investing activities Capital expenditures — — (1,186.1 ) — (1,186.1 ) Other investing activities — 24.1 (26.5 ) — (2.4 ) Cash provided by (used in) investing activities — 24.1 (1,212.6 ) — (1,188.5 ) Financing activities Cash distributions: General and limited partners (1,230.5 ) (1,230.5 ) — 1,230.5 (1,230.5 ) Noncontrolling interests — — (11.7 ) — (11.7 ) Intercompany borrowings (advances), net (1,295.1 ) 1,102.1 193.0 — — Borrowing (repayment) of short-term borrowings, net (509.0 ) — — — (509.0 ) Issuance of long-term debt, net of discounts 798.9 — — — 798.9 Debt financing costs (7.7 ) — — — (7.7 ) Repayment of long-term debt — — (7.6 ) — (7.6 ) Issuance of common units, net of issuance costs 1,025.7 — — — 1,025.7 Contribution from general partner 21.0 — — — 21.0 Cash provided by (used in) financing activities (1,196.7 ) (128.4 ) 173.7 1,230.5 79.1 Change in cash and cash equivalents — (37.4 ) — — (37.4 ) Cash and cash equivalents at beginning of period — 42.5 — — 42.5 Cash and cash equivalents at end of period $ — $ 5.1 $ — $ — $ 5.1 Year Ended December 31, 2014 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 1,155.7 $ 69.8 $ 1,136.5 $ (1,052.2 ) $ 1,309.8 Investing activities Capital expenditures — — (1,746.0 ) — (1,746.0 ) Other investing activities — 17.7 (804.7 ) — (787.0 ) Cash provided by (used in) investing activities — 17.7 (2,550.7 ) — (2,533.0 ) Financing activities Cash distributions: General and limited partners (1,052.2 ) (1,052.2 ) — 1,052.2 (1,052.2 ) Noncontrolling interests — — (0.6 ) — (0.6 ) Intercompany borrowings (advances), net (2,295.2 ) 872.7 1,422.5 — — Borrowing (repayment) of short-term borrowings, net 1,055.3 — — — 1,055.3 Repayment of long-term debt — — (7.7 ) — (7.7 ) Issuance of common units, net of issuance costs 1,113.1 — — — 1,113.1 Contribution from general partner 23.3 — — — 23.3 Cash provided by (used in) financing activities (1,155.7 ) (179.5 ) 1,414.2 1,052.2 1,131.2 Change in cash and cash equivalents — (92.0 ) — — (92.0 ) Cash and cash equivalents at beginning of period — 134.5 — — 134.5 Cash and cash equivalents at end of period $ — $ 42.5 $ — $ — $ 42.5 Year Ended December 31, 2013 Parent Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 870.7 $ 65.1 $ 981.6 $ (909.7 ) $ 1,007.7 Investing activities Capital expenditures — (2.6 ) (1,936.7 ) — (1,939.3 ) Other investing activities — (11.4 ) (375.4 ) — (386.8 ) Cash provided by (used in) investing activities — (14.0 ) (2,312.1 ) — (2,326.1 ) Financing activities Cash distributions: General and limited partners (909.7 ) (909.7 ) — 909.7 (909.7 ) Noncontrolling interests — — (0.6 ) — (0.6 ) Intercompany borrowings (advances), net (1,794.8 ) 456.0 1,338.8 — — Issuance of long-term debt, net of discounts 1,247.8 — — — 1,247.8 Debt financing costs (10.2 ) — — — (10.2 ) Repayment of long-term debt — — (7.7 ) — (7.7 ) Issuance of common units, net of issuance costs 583.9 — — — 583.9 Contribution from general partner 12.3 — — — 12.3 Cash provided by (used in) financing activities (870.7 ) (453.7 ) 1,330.5 909.7 915.8 Change in cash and cash equivalents — (402.6 ) — — (402.6 ) Cash and cash equivalents at beginning of period — 537.1 — — 537.1 Cash and cash equivalents at end of period $ — $ 134.5 $ — $ — $ 134.5

SUMMARY OF SIGNIFICANT ACCOUN49

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Entity [Line Items]
General partnership ownership interest (in hundredths)	41.20%	37.80%
Limited Liability Company (LLC) or Limited Partnership (LP), Members or Limited Partners, Ownership Interest	98.00%
Regulatory Assets	$ 5.8	$ 6.1
Maximum Time Period Regulatory Assets Are Being Recovered (In Years)	40 years
Long-term Debt [Member] | Accounting Standards Update 2015-03 [Member]
Entity [Line Items]
New Accounting Pronouncement or Change in Accounting Principle, Effect of Adoption, Quantification		$ 34.1
General Partner [Member]
Entity [Line Items]
General partnership ownership interest (in hundredths)	2.00%

ACQUISITIONS ACQUISITIONS (Deta

ACQUISITIONS ACQUISITIONS (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2014USD ($)Rate	Dec. 31, 2013USD ($)RateMMcf
West Texas LPG and Mesquite Systems [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Cash	$ 13,839
Accounts receivable	9,132
Other current assets	3,369
Property, plant and equipment	970,359
Fair value of assets acquired	996,699
Accounts payable	(8,621)
Other liabilities	(10,867)
Total fair value of liabilities acquired	(19,488)
Less: Fair value of noncontrolling interest	(162,438)
Net assets acquired	814,773
Less: Cash received	(13,839)
Net cash paid for acquisition	$ 800,934
Acquisition date	Nov. 30, 2014
Sage Creek Natural Gas Gathering And Processing [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets		$ 103,000
Fair value of assets acquired		212,889
Goodwill		92,000
Net cash paid for acquisition		$ 304,889
Acquisition date		Sep. 30, 2013
Processing capacity of natural gas processing plant, per day | MMcf		50
Sage Creek Natural Gas Gathering And Processing [Member] | Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Useful life		20 years
Sage Creek Natural Gas Gathering And Processing [Member] | Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Useful life		30 years
Maysville Natural Gas Processing Facility [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Net cash paid for acquisition		$ 90,000
Business Acquisition, Percentage of Voting Interests Acquired | Rate		30.00%
Acquisition date		Dec. 1, 2013
Current ownership share in Maysville natural gas processing facility | Rate		100.00%
West Texas LPG Pipeline Limited Partnership [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business Acquisition, Description of Acquired Entity	80 percent interest
Mesquite Pipeline [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Business Acquisition, Percentage of Voting Interests Acquired | Rate	100.00%
Regulated Operation [Member] | West Texas LPG and Mesquite Systems [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Property, plant and equipment	$ 812,716
Nonregulated Operation [Member] | West Texas LPG and Mesquite Systems [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Property, plant and equipment	$ 157,643
Pipelines [Member] | Sage Creek Natural Gas Gathering And Processing [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Property, plant and equipment		$ 59,174
Processing and fractionation and related equipment [member] | Sage Creek Natural Gas Gathering And Processing [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Property, plant and equipment		50,595
Manufacturing Facility [Member] | Sage Creek Natural Gas Gathering And Processing [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Property, plant and equipment		120
Natural Gas Gathering And Processing [Member] | Sage Creek Natural Gas Gathering And Processing [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets		40,000
Fair value of assets acquired		131,844
Goodwill		20,000
Net cash paid for acquisition		151,844
Natural Gas Gathering And Processing [Member] | Pipelines [Member] | Sage Creek Natural Gas Gathering And Processing [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Property, plant and equipment		41,129
Natural Gas Gathering And Processing [Member] | Processing and fractionation and related equipment [member] | Sage Creek Natural Gas Gathering And Processing [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Property, plant and equipment		50,595
Natural Gas Gathering And Processing [Member] | Manufacturing Facility [Member] | Sage Creek Natural Gas Gathering And Processing [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Property, plant and equipment		120
Natural Gas Liquids [Member] | Sage Creek Natural Gas Gathering And Processing [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Intangible assets		63,000
Fair value of assets acquired		81,045
Goodwill		72,000
Net cash paid for acquisition		153,045
Natural Gas Liquids [Member] | Pipelines [Member] | Sage Creek Natural Gas Gathering And Processing [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Property, plant and equipment		18,045
Natural Gas Liquids [Member] | Processing and fractionation and related equipment [member] | Sage Creek Natural Gas Gathering And Processing [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Property, plant and equipment		0
Natural Gas Liquids [Member] | Manufacturing Facility [Member] | Sage Creek Natural Gas Gathering And Processing [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Property, plant and equipment		$ 0

FAIR VALUE MEASUREMENTS - Part

FAIR VALUE MEASUREMENTS - Part 1 (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-term Debt, Fair Value	$ 6,200,000	$ 6,400,000
Long-term Debt	6,800,000	6,000,000
Cash collateral held under master netting arrangements	34,400	24,800
Cash collateral posted under master netting arrangements	0	0
Fair Value, Measurements, Recurring [Member]
Derivative assets
Commodity contracts - financial	3,760	17,255
Commodity contracts - physical	3,591	9,922
Interest rate contracts		2,288
Total derivative assets	7,351	29,465
Derivative Liabilities
Commodity contracts - financial	0	0
Commodity contracts - physical		(23)
Interest rate contracts	(9,936)	(44,843)
Total derivative liabilities	(9,936)	(44,866)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative assets
Commodity contracts - financial	38,921	42,880
Commodity contracts - physical	0	0
Interest rate contracts		0
Total derivative assets	38,921	42,880
Derivative Liabilities
Commodity contracts - financial	(4,513)	(169)
Commodity contracts - physical		0
Interest rate contracts	0	0
Total derivative liabilities	(4,513)	(169)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative assets
Commodity contracts - financial	0	0
Commodity contracts - physical	0	0
Interest rate contracts		2,288
Total derivative assets	0	2,288
Derivative Liabilities
Commodity contracts - financial	0	0
Commodity contracts - physical		0
Interest rate contracts	(9,936)	(44,843)
Total derivative liabilities	(9,936)	(44,843)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Derivative assets
Commodity contracts - financial	7,253	354
Commodity contracts - physical	3,591	9,922
Interest rate contracts		0
Total derivative assets	10,844	10,276
Derivative Liabilities
Commodity contracts - financial	(3,513)	(968)
Commodity contracts - physical		(23)
Interest rate contracts	0	0
Total derivative liabilities	(3,513)	(991)
Fair Value, Measurements, Recurring [Member] | Total Gross [Member]
Derivative assets
Commodity contracts - financial	46,174	43,234
Commodity contracts - physical	3,591	9,922
Interest rate contracts		2,288
Total derivative assets	49,765	55,444
Derivative Liabilities
Commodity contracts - financial	(8,026)	(1,137)
Commodity contracts - physical		(23)
Interest rate contracts	(9,936)	(44,843)
Total derivative liabilities	(17,962)	(46,003)
Fair Value, Measurements, Recurring [Member] | Netting [Member]
Derivative assets
Commodity contracts - financial	(42,414)	(25,979)
Commodity contracts - physical	0	0
Interest rate contracts		0
Total derivative assets	(42,414)	(25,979)
Derivative Liabilities
Commodity contracts - financial	8,026	1,137
Commodity contracts - physical		0
Interest rate contracts	0	0
Total derivative liabilities	$ 8,026	$ 1,137

FAIR VALUE MEASUREMENTS - Par52

FAIR VALUE MEASUREMENTS - Part 2 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Fair Value, Assets And Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Transfers between levels	$ 0	$ 0
Derivative Financial Instruments Assets Liabilities Net [Member]
Fair Value, Assets And Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Net assets (liabilities) at beginning of period	9,285	(782)
Total realized/unrealized gains (losses): [Abstract]
Included in earnings	216	(927)
Included in other comprehensive income (loss)	(2,170)	7,260
Settlements	0	3,734
Net assets (liabilities) at end of period	$ 7,331	$ 9,285

RISK MANAGEMENT AND HEDGING A53

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES - Part 1 (Details) - USD ($)	Dec. 31, 2015	Dec. 31, 2014
Derivatives, Fair Value [Line Items]
Assets	$ 49,765,000	$ 55,444,000
(Liabilities)	(17,962,000)	(46,003,000)
Derivative, Net Liability Position, Aggregate Fair Value	0
Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Assets	42,846,000	55,444,000
(Liabilities)	(11,376,000)	(45,980,000)
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member]
Derivatives, Fair Value [Line Items]
Assets	0	2,288,000
(Liabilities)	(9,936,000)	(44,843,000)
Designated as Hedging Instrument [Member] | Financial Derivative Instrument [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Assets	39,255,000	43,234,000
(Liabilities)	(1,440,000)	(1,137,000)
Designated as Hedging Instrument [Member] | Physical Derivative Instrument [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Assets	3,591,000	9,922,000
(Liabilities)	0	0
Not Designated as Hedging Instrument [Member]
Derivatives, Fair Value [Line Items]
Assets	6,919,000	0
(Liabilities)	(6,586,000)	(23,000)
Not Designated as Hedging Instrument [Member] | Financial Derivative Instrument [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Assets	6,919,000	0
(Liabilities)	(6,586,000)	0
Not Designated as Hedging Instrument [Member] | Physical Derivative Instrument [Member] | Commodity Contract [Member]
Derivatives, Fair Value [Line Items]
Assets	0	0
(Liabilities)	0	(23,000)
Natural Gas Pipelines [Member]
Derivatives, Fair Value [Line Items]
Derivative, Fair Value, Net	$ 0	$ 0

RISK MANAGEMENT AND HEDGING A54

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES - Part 2 (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)MMcfMMBbls	Mar. 31, 2016USD ($)	Dec. 31, 2014USD ($)MMcfMMBbls
Derivative [Line Items]
Notional Amount Of Cash Flow Hedge Instruments Settled	$ 500
Interest Rate Contract [Member] | Forward Contracts [Member]
Derivative [Line Items]
Notional Amount Of Cash Flow Hedge Instruments Less Than 12 Months	$ 400
Not Designated as Hedging Instrument [Member] | Crude oil and NGLs [Member] | Fixed Price [Member] | Purchased [Member] | Futures, forwards and swaps [Member]
Derivative [Line Items]
Notional amount | MMBbls	0.6		0
Not Designated as Hedging Instrument [Member] | Crude oil and NGLs [Member] | Fixed Price [Member] | Sold [Member] | Futures, forwards and swaps [Member]
Derivative [Line Items]
Notional amount | MMBbls	(0.6)		0
Designated as Hedging Instrument [Member] | Crude oil and NGLs [Member] | Fixed Price [Member] | Purchased [Member] | Futures, forwards and swaps [Member]
Derivative [Line Items]
Notional amount | MMBbls	0		0
Designated as Hedging Instrument [Member] | Crude oil and NGLs [Member] | Fixed Price [Member] | Sold [Member] | Futures, forwards and swaps [Member]
Derivative [Line Items]
Notional amount | MMBbls	(2.3)		(0.5)
Designated as Hedging Instrument [Member] | Natural Gas [Member] | Fixed Price [Member] | Purchased [Member] | Futures and swaps [Member]
Derivative [Line Items]
Notional amount | MMcf	0		0
Designated as Hedging Instrument [Member] | Natural Gas [Member] | Fixed Price [Member] | Sold [Member] | Futures and swaps [Member]
Derivative [Line Items]
Notional amount | MMcf	(27,100)		(41,200)
Designated as Hedging Instrument [Member] | Natural Gas [Member] | Basis [Member] | Purchased [Member] | Futures and swaps [Member]
Derivative [Line Items]
Notional amount | MMcf	0		0
Designated as Hedging Instrument [Member] | Natural Gas [Member] | Basis [Member] | Sold [Member] | Futures and swaps [Member]
Derivative [Line Items]
Notional amount | MMcf	(27,100)		(41,200)
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Purchased [Member] | Forward Starting Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 400		$ 900
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Sold [Member] | Forward Starting Interest Rate Swap [Member]
Derivative [Line Items]
Derivative, Notional Amount	$ 0		$ 0
For Period April 2016 through July 2018 [Member] | Subsequent Event [Member] | Interest Rate Contract [Member] | Cash Flow Hedging [Member] | Forward Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 1,000
For Period July 2018 through January 2019 [Member] | Subsequent Event [Member] | Interest Rate Contract [Member] | Cash Flow Hedging [Member] | Forward Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount		$ 500

RISK MANAGEMENT AND HEDGING A55

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES - Part 3 (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Derivative Instruments, Gain (Loss) [Line Items]
Realized Loss On Settled Interest Rate Swaps Recorded in AOCI	$ 55,100
Net unrealized loss in accumulated other comprehensive income (loss)	(113,282)	$ (91,823)	$ (58,837)
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	47,500	(64,639)	32,141
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income (effective portion)	67,034	(31,653)	(8,344)
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	0	0	0
Commodity Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income (effective portion)	(81,089)	21,052	(1,689)
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	41,500
Price Risk Cash Flow Hedge Unrealized Gain (Loss) to be Reclassified During Next 12 Months	41,500
Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income (effective portion)	14,055	10,601	10,033
Interest Rate Contract [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	(15,700)
Amount of accumulated other comprehensive income (loss) attributable primarily to settled interest-rate swaps.	(141,700)
Interest Rate Contract [Member] | Interest Expense [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income (effective portion)	(14,055)	(10,601)	(10,033)
Continuing Operations [Member] | Commodity Contract [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	70,065	32,354	(14,475)
Continuing Operations [Member] | Commodity Contract [Member] | Sales [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Total gain (loss) reclassified from accumulated other comprehensive income (loss) into net income (effective portion)	81,089	(21,052)	1,689
Continuing Operations [Member] | Interest Rate Contract [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	$ (22,565)	$ (96,993)	$ 46,616

PROPERTY, PLANT AND EQUIPMENT -

PROPERTY, PLANT AND EQUIPMENT - (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 14,307,546	$ 13,377,617
Accumulated depreciation and amortization	(2,050,755)	(1,842,084)
Property, Plant and Equipment, Net	12,256,791	11,535,533
Construction in Progress Expenditures Incurred but Not yet Paid	115,700	187,200	$ 226,700
Impairment of long-lived assets	83,673	0	$ 0
Non-Regulated Property, Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	(1,219,435)	(1,123,261)
Non-Regulated Property, Plant and Equipment [Member] | Gathering pipelines and related equipment [member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	2,961,388	2,449,343
Non-Regulated Property, Plant and Equipment [Member] | Processing and fractionation and related equipment [member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	3,627,062	2,880,572
Non-Regulated Property, Plant and Equipment [Member] | Storage and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	456,437	478,276
Non-Regulated Property, Plant and Equipment [Member] | Transmission pipelines and related equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	416,391	518,585
Non-Regulated Property, Plant and Equipment [Member] | General plant and other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	186,358	142,276
Non-Regulated Property, Plant and Equipment [Member] | Construction Work in Process [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	690,179	1,233,808
Regulated Property Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Accumulated depreciation and amortization	(831,320)	(718,823)
Regulated Property Plant and Equipment [Member] | Storage and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	76,468	115,799
Regulated Property Plant and Equipment [Member] | General plant and other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	94,461	63,424
Regulated Property Plant and Equipment [Member] | Construction Work in Process [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	83,461	194,700
Regulated Property Plant and Equipment [Member] | Natural Gas Transmission Pipelines and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	1,507,220	1,478,035
Regulated Property Plant and Equipment [Member] | Natural Gas Liquids Transmission Pipelines and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Gross	$ 4,208,121	$ 3,822,799
Minimum [Member] | Non-Regulated Property, Plant and Equipment [Member] | Gathering pipelines and related equipment [member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Minimum [Member] | Non-Regulated Property, Plant and Equipment [Member] | Processing and fractionation and related equipment [member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Minimum [Member] | Non-Regulated Property, Plant and Equipment [Member] | Storage and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Minimum [Member] | Non-Regulated Property, Plant and Equipment [Member] | Transmission pipelines and related equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Minimum [Member] | Non-Regulated Property, Plant and Equipment [Member] | General plant and other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Minimum [Member] | Regulated Property Plant and Equipment [Member] | Storage and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Minimum [Member] | Regulated Property Plant and Equipment [Member] | General plant and other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	2 years
Minimum [Member] | Regulated Property Plant and Equipment [Member] | Natural Gas Transmission Pipelines and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Minimum [Member] | Regulated Property Plant and Equipment [Member] | Natural Gas Liquids Transmission Pipelines and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	5 years
Maximum [Member] | Non-Regulated Property, Plant and Equipment [Member] | Gathering pipelines and related equipment [member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Maximum [Member] | Non-Regulated Property, Plant and Equipment [Member] | Processing and fractionation and related equipment [member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Maximum [Member] | Non-Regulated Property, Plant and Equipment [Member] | Storage and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	54 years
Maximum [Member] | Non-Regulated Property, Plant and Equipment [Member] | Transmission pipelines and related equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	54 years
Maximum [Member] | Non-Regulated Property, Plant and Equipment [Member] | General plant and other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	60 years
Maximum [Member] | Regulated Property Plant and Equipment [Member] | Storage and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	54 years
Maximum [Member] | Regulated Property Plant and Equipment [Member] | General plant and other [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	54 years
Maximum [Member] | Regulated Property Plant and Equipment [Member] | Natural Gas Transmission Pipelines and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	77 years
Maximum [Member] | Regulated Property Plant and Equipment [Member] | Natural Gas Liquids Transmission Pipelines and Related Equipment [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment, Useful Life	88 years
Natural Gas Gathering And Processing [Member]
Property, Plant and Equipment [Line Items]
Impairment of long-lived assets	$ 63,500
Natural Gas Liquids [Member] | Regulated Property Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Average Depreciation Rate	1.90%	2.00%	2.00%
Natural Gas Pipelines [Member] | Regulated Property Plant and Equipment [Member]
Property, Plant and Equipment [Line Items]
Average Depreciation Rate	2.10%	2.10%	2.20%
Natural Gas Gathering And Processing and Natural Gas Liquids [Member]
Property, Plant and Equipment [Line Items]
Impairment of long-lived assets	$ 20,200

GOODWILL AND INTANGIBLE ASSET57

GOODWILL AND INTANGIBLE ASSETS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Goodwill	$ 488,718	$ 488,718
Amortization expense for intangible assets	11,900	11,800	$ 8,700
Future amortization expense for next five years [Abstract]
Future amortization expense, year one	11,900
Future amortization expense, year two	11,900
Future amortization expense, year three	11,900
Future amortization expense, year four	11,900
Future amortization expense, year five	11,900
Gross intangible assets and accumulated amortization [Abstract]
Gross intangible assets	426,068	411,650
Accumulated amortization	(89,909)	(78,010)
Net intangible assets	336,159	333,640
Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Goodwill	112,141	112,141
Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Goodwill	129,011	129,011
Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Goodwill	$ 247,566	$ 247,566
Minimum [Member] | Natural Gas Gathering And Processing and Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Finite-Lived Intangible Asset, Useful Life	20 years
Maximum [Member] | Natural Gas Gathering And Processing and Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Finite-Lived Intangible Asset, Useful Life	40 years

SHORT-TERM BORROWINGS (Details)

SHORT-TERM BORROWINGS (Details) $ in Millions	12 Months Ended
	Dec. 31, 2015USD ($)Rate	Dec. 31, 2014USD ($)Rate
Commercial Paper [Member]
Line of Credit Facility [Line Items]
Commercial paper outstanding	$ 246.3	$ 1,100
Weighted average for Commercial Paper Outstanding | Rate	1.23%	0.54%
Maximum Amount Of Commercial Paper	$ 2,400	$ 1,700
Partnership Credit Agreement [Member]
Line of Credit Facility [Line Items]
Letters of credit issued	14	14
Borrowings outstanding under our Partnership Credit Agreement	$ 300	0
Average interest rate for Partnership Credit Agreement | Rate	1.60%
Line of Credit Facility, Remaining Borrowing Capacity	$ 1,800
Line of Credit Facility, Maximum Borrowing Capacity	2,400	$ 1,700
Sublimit for issuance of standby letters of credit	100
Swingline subfacility	$ 150
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	4.4
Interest rate description	borrowings, if any, will accrue at LIBOR plus 117.5 basis points
Line Of Credit Facility, Annual Facility Fee Description	the annual facility fee is 20 basis points

LONG-TERM DEBT (Details)

LONG-TERM DEBT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2013	Mar. 31, 2016	Dec. 31, 2014
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 6,851,907			$ 6,059,557
Unamortized debt discount and other	(48,945)			(47,675)
Current maturities	(107,650)			(7,650)
Long-term debt	6,695,312			6,004,232
Long-term Debt, by Maturity [Abstract]
2,016	1,107,700
2,017	407,700
2,018	432,700
2,019	507,700
2,020	$ 307,700
ONEOK Partners [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate Terms	LIBOR plus 130.0 basis points
Long-term Debt, by Maturity [Abstract]
2,016	$ 1,100,000
2,017	400,000
2,018	425,000
2,019	500,000
2,020	300,000
ONEOK Partners [Member] | Note Payable from Public Offering Due 2016 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 650,000			650,000
Interest rates (in hundredths)	3.25%
ONEOK Partners [Member] | Notes Payable due 2016 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 450,000			450,000
Current maturities	$ 100,000
Interest rates (in hundredths)	6.15%
Long-term Debt, by Maturity [Abstract]
Amount of debt classified as long-term	$ 1,000,000
ONEOK Partners [Member] | Note Payable from Public Offering Due 2017 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 400,000			400,000
Interest rates (in hundredths)	2.00%
ONEOK Partners [Member] | Note Payable from Public Offering Due 2018 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 425,000	$ 425,000		425,000
Interest rates (in hundredths)	3.20%	3.20%
ONEOK Partners [Member] | Notes Payables due 2019 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 500,000			500,000
Interest rates (in hundredths)	8.625%
ONEOK Partners [Member] | Note Payable from Public Offering Due 2020 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 300,000			0
Interest rates (in hundredths)	3.80%
ONEOK Partners [Member] | Note Payable 2 from Public Offering Due 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 900,000			900,000
Interest rates (in hundredths)	3.375%
ONEOK Partners [Member] | Note Payable from Public Offering Due 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 425,000	$ 425,000		425,000
Interest rates (in hundredths)	5.00%	5.00%
ONEOK Partners [Member] | Note Payable from Public Offering Due 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 500,000			0
Interest rates (in hundredths)	4.90%
ONEOK Partners [Member] | Notes Payables due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 600,000			600,000
Interest rates (in hundredths)	6.65%
ONEOK Partners [Member] | Notes Payables due 2037 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 600,000			600,000
Interest rates (in hundredths)	6.85%
ONEOK Partners [Member] | Note Payable from Public Offering Due 2041 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 650,000			650,000
Interest rates (in hundredths)	6.125%
ONEOK Partners [Member] | Note Payable from Public Offering Due 2043 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 400,000	$ 400,000		400,000
Interest rates (in hundredths)	6.20%	6.20%
Guardian Pipeline [Member] | Notes Payables due 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 51,907			$ 59,557
Long-term Debt, by Maturity [Abstract]
2,016	7,700
2,017	7,700
2,018	7,700
2,019	7,700
2,020	$ 7,700
Debt instrument covenant description	Guardian Pipeline’s senior notes contain financial covenants that require the maintenance of certain financial ratios as defined in the master shelf agreement based on Guardian Pipeline’s financial position and results of operations. Upon any breach of these covenants, all amounts outstanding under the master shelf agreement may become due and payable immediately.
Average interest rate (in hundredths)	7.88%
Debt Instrument, Covenant Compliance	At December 31, 2015, Guardian Pipeline was in compliance with its financial covenants
Senior Notes [Member] | ONEOK Partners [Member]
Long-term Debt, by Maturity [Abstract]
Net proceeds from the public offering	$ 792,300	$ 1,240,000
Senior Notes, Noncurrent	$ 800,000	$ 1,250,000
Debt instrument covenant description	Our senior notes are governed by an indenture, dated as of September 25, 2006, between us and Wells Fargo Bank, N.A., the trustee, as supplemented. The indenture does not limit the aggregate principal amount of debt securities that may be issued and provides that debt securities may be issued from time to time in one or more additional series. The indenture contains covenants including, among other provisions, limitations on our ability to place liens on our property or assets and to sell and lease back our property. The indenture includes an event of default upon acceleration of other indebtedness of $100 million or more. Such events of default would entitle the trustee or the holders of 25 percent in aggregate principal amount of any of our outstanding senior notes to declare those notes immediately due and payable in full.
Debt instrument call feature	We may redeem our 6.15 percent senior notes due 2016 and our senior notes due 2019, 2036 and 2037, in whole or in part, at any time prior to their maturity at a redemption price equal to the principal amount, plus accrued and unpaid interest and a make-whole premium. The redemption price will never be less than 100 percent of the principal amount of the respective note plus accrued and unpaid interest to the redemption date. We may redeem our senior notes due 2017 and our senior notes due 2022 at par starting one month and three months, respectively, before their maturity dates. We may redeem our senior notes due 2041 at a redemption price equal to the principal amount, plus accrued and unpaid interest, starting six months before its maturity date. Prior to that date, we may redeem these notes, in whole or in part, at a redemption price equal to the principal amount, plus accrued and unpaid interest and a make-whole premium. We may redeem our senior notes due 2018, 2020, 2023, 2025, and 2043 at par, plus accrued and unpaid interest to the redemption date, starting one month, one month, three months, three months, and six months, respectively, before their maturity dates. Prior to these dates, we may redeem these notes, in whole or in part, at a redemption price equal to the principal amount, plus accrued and unpaid interest and a make-whole premium. The redemption price will never be less than 100 percent of the principal amount of the respective note plus accrued and unpaid interest to the redemption date.
Subsequent Event [Member] | Term Loan Agreement [Member] | ONEOK Partners [Member]
Long-term Debt, by Maturity [Abstract]
Delayed-Draw Unsecured Senior Term Loan			$ 1,000,000

EQUITY (Details)

EQUITY (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended													12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2012	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Equity [Abstract]
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.
Partnership Capital Distributions [Line Items]
General partnership ownership interest (in hundredths)														41.20%	37.80%
Rights to receive increased quarterly distribution on Class B Units														Our Class B limited partner units are entitled to receive increased quarterly distributions equal to 110 percent of the distributions paid with respect to our common units.
Number of days notice of withdrawal of waiver (in days)														90 days
Number of common units owned by related party	41,300													41,300
Aggregate dollar 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													138,000
Contribution from general partner														20,990	$ 23,155	$ 12,366
Total distributions														$ 1,242,165	$ 1,052,794	$ 910,301
Percentage of increase in quarterly distributions entitled to Class B limited partners units														123.50%
Percentage of increase in quarterly distribution payable on Class B limited partner units upon removal of general partner														123.50%
General Partner [Member]
Partnership Capital Distributions [Line Items]
General partnership ownership interest (in hundredths)														2.00%
Dividend Paid [Member]
Partnership Capital Distributions [Line Items]
Distributions Per Limited Partnership and General Partnership Unit, Outstanding, Basic														$ 3.160	$ 3.010	$ 2.870
Total distributions														$ 1,230,475	$ 1,052,245	$ 909,713
Dividend Paid [Member] | General Partner [Member]
Partnership Capital Distributions [Line Items]
General partner distributions														24,610	21,044	18,193
Incentive distribution														371,500	304,999	251,664
Distributions to general partner														396,110	326,043	269,857
Dividend Paid [Member] | Limited Partner [Member]
Partnership Capital Distributions [Line Items]
Limited partner distributions to ONEOK														310,230	279,292	266,302
Partners Capital Account Distributions to Other Unitholders														$ 524,135	$ 446,910	$ 373,554
Dividend Declared [Member]
Partnership Capital Distributions [Line Items]
Distributions Per Limited Partnership and General Partnership Unit, Outstanding, Basic	$ 0.790	$ 0.790	$ 0.790	$ 0.790	$ 0.790	$ 0.775	$ 0.760	$ 0.745	$ 0.730	$ 0.725	$ 0.720	$ 0.715	$ 0.710	$ 3.160	$ 3.070	$ 2.890
Total distributions														$ 1,267,770	$ 1,105,457	$ 931,236
Dividend Declared [Member] | General Partner [Member]
Partnership Capital Distributions [Line Items]
General partner distributions														25,356	22,109	18,625
Incentive distribution														382,759	326,022	259,466
Distributions to general partner														408,115	348,131	278,091
Dividend Declared [Member] | Limited Partner [Member]
Partnership Capital Distributions [Line Items]
Limited partner distributions to ONEOK														327,250	284,860	268,157
Partners Capital Account Distributions to Other Unitholders														$ 532,405	$ 472,466	$ 384,988
Issued under public offering [Member]
Partnership Capital Distributions [Line Items]
Partners' Capital Account, Units, Sold in Public Offering							13,900			11,500
Public offering price of common units							$ 52.94			$ 49.61
Proceeds from Sale of Interest in Partnership Unit							$ 714,500			$ 553,400
Contribution from general partner							$ 15,000			$ 11,600
Issued under private placement [Member]
Partnership Capital Distributions [Line Items]
Partners Capital Account Units Sold Under Equity Distribution Agreement		3,300
Number of common units to related party in a private placement (in number of units)		21,500
Per Unit Offering Price Under Private Placement		$ 30.17
Proceeds from Sale of Interest in Partnership Unit		$ 749,000
Contribution from general partner		$ 15,300
Issued Under Equity Distribution Agreement [Member]
Partnership Capital Distributions [Line Items]
Partners Capital Account Units Sold Under Equity Distribution Agreement														10,500	7,900	681
Proceeds from Sale of Interest in Partnership Unit														$ 381,600	$ 402,100	$ 36,100
West Texas LPG Pipeline Limited Partnership [Member]
Partnership Capital Distributions [Line Items]
Business Acquisition, Description of Acquired Entity															80 percent interest
West Texas LPG and Mesquite Systems [Member]
Partnership Capital Distributions [Line Items]
Acquisition date															Nov. 30, 2014

ACCUMULATED OTHER COMPREHENSI61

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Accumulated other comprehensive loss - January 1	$ (91,823)	$ (58,837)
Other comprehensive income (loss) before reclassifications	45,575	(64,639)	$ 32,141
Amounts reclassified from accumulated other comprehensive income (loss)	(67,034)	31,653	8,344
Net current-period other comprehensive income (loss) attributable to ONEOK Partners, L.P.	(21,459)	(32,986)	40,485
Accumulated other comprehensive loss - December 31	(113,282)	(91,823)	(58,837)
Commodity Contract [Member]
Unrealized (gains) losses on risk-management assets/liabilities	(81,089)	21,052	(1,689)
Interest Rate Contract [Member]
Unrealized (gains) losses on risk-management assets/liabilities	$ 14,055	$ 10,601	$ 10,033

LIMITED PARTNERS' NET INCOME 62

LIMITED PARTNERS' NET INCOME PER UNIT (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Incentive Distribution Made to Managing Member or General Partner [Line Items]
Number of days notice of withdrawal of waiver (in days)	90 days
General partnership ownership interest (in hundredths)	41.20%	37.80%
General Partner [Member]
Incentive Distribution Made to Managing Member or General Partner [Line Items]
General partnership ownership interest (in hundredths)	2.00%
General Partner [Member] | Dividend Declared [Member]
Incentive Distribution Made to Managing Member or General Partner [Line Items]
Incentive distribution allocated to general partner	$ 382,759	$ 326,022	$ 259,466

INCOME TAXES (Details)

INCOME TAXES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Current Income Tax Expense (Benefit), Continuing Operations [Abstract]
Federal	$ 0	$ 59	$ 56
State	(621)	1,777	5,358
Total current income tax provision	(621)	1,836	5,414
Deferred income tax provision
Federal	5,413	5,033	4,303
State	(648)	5,799	1,141
Total deferred income tax provision	4,765	10,832	5,444
Income Tax Reconciliation [Abstract]
Income before income taxes	602,016	924,003	814,841
Less: Net income attributable to noncontrolling interests	8,330	1,037	357
Income attributable to ONEOK Partners, L.P. before income taxes	$ 593,686	$ 922,966	$ 814,484
Federal statutory income tax rate	35.00%	35.00%	35.00%
Provision for federal income taxes	$ 207,790	$ 323,038	$ 285,069
Effective Income Tax Rate Reconciliation, Tax Exempt Income, Amount	202,143	318,021	280,992
State income taxes, net of federal benefit	(2,078)	7,576	6,095
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount	810	0	0
Other, net	(235)	75	686
Income tax provision	4,144	12,668	$ 10,858
Deferred tax assets
Federal and state net operating loss	4,224	3,179
Other	7	1,626
Total deferred tax assets	4,231	4,805
Deferred tax liabilities
Excess of tax over book depreciation	67,265	61,120
Regulatory assets	49	1,962
Total deferred tax liabilities	67,314	63,082
Net deferred tax liabilities	$ 63,083	$ 58,277

UNCONSOLIDATED AFFILIATES (Deta

UNCONSOLIDATED AFFILIATES (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 948,221	$ 1,132,653	$ 1,229,838
Equity Method Goodwill	40,100	170,900
Equity in net earnings from investments	125,300	117,415	110,517
Equity Method Investment, Other than Temporary Impairment	(180,583)	(76,412)	0
Accounts Payable, Related Parties, Current	8,000	20,500
Payments to Acquire Other Investments	27,540	1,063	35,308
Balance Sheet [Abstract]
Current assets	149,439	153,293
Property, plant and equipment, net	2,556,559	2,440,714
Other noncurrent assets	23,722	35,668
Current liabilities	211,037	95,026
Long-term debt	425,521	428,385
Other noncurrent liabilities	69,356	73,767
Accumulated other comprehensive loss	(5,669)	(2,063)
Owners' equity	2,029,475	2,034,560
Income Statement [Abstract]
Operating revenues	524,496	548,491	528,665
Operating expenses	304,930	309,990	256,292
Net income	200,064	214,410	248,998
Distributions paid to us	155,918	139,019	137,498
Unconsolidated Affiliates [Member]
Schedule of Equity Method Investments [Line Items]
Related Party Transaction, Expenses from Transactions with Related Party	104,700	62,000	53,800
Overland Pass Pipeline Company [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 459,354	$ 466,977
Net ownership percentage	50.00%	50.00%
Equity in net earnings from investments	$ 37,783	$ 25,906	20,461
Northern Border Pipeline [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 363,231	$ 387,253
Net ownership percentage	50.00%	50.00%
Equity in net earnings from investments	$ 66,941	$ 69,819	65,046
Payments to Acquire Other Investments			30,800
Fort Union Gas Gathering LLC [Member]
Schedule of Equity Method Investments [Line Items]
Net ownership percentage	37.00%
Lost Creek Gathering Company [Member]
Schedule of Equity Method Investments [Line Items]
Net ownership percentage	35.00%
Bighorn Gas Gathering LLC [Member]
Schedule of Equity Method Investments [Line Items]
Net ownership percentage	49.00%
Other Unconsolidated Affiliate [Member]
Schedule of Equity Method Investments [Line Items]
Investments in unconsolidated affiliates	$ 125,636	278,423
Equity in net earnings from investments	20,576	$ 21,690	$ 25,010
Roadrunner Gas Transmission [Member]
Income Statement [Abstract]
Payments to Acquire Equity Method Investments	30,000
Powder River Basin Other Than Bighorn Gas Gathering [Member]
Income Statement [Abstract]
Equity Method Investment, Underlying Equity In Net Assets	$ 35,000

RELATED-PARTY TRANSACTIONS (Det

RELATED-PARTY TRANSACTIONS (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Related Party Transactions [Abstract]
General partnership ownership interest (in hundredths)	41.20%	37.80%
Related Party Transaction [Line Items]
Contribution from general partner	$ 20,990	$ 23,155	$ 12,366
ONEOK [Member]
Transactions With Related Parties [Abstract]
Revenues	0	53,526	340,743
Expenses [Abstract]
Cost of sales and fuel	0	10,835	37,963
Operating expenses	368,346	330,541	265,448
Total expenses	$ 368,346	$ 341,376	$ 303,411
General Partner [Member]
Related Party Transactions [Abstract]
General partnership ownership interest (in hundredths)	2.00%

COMMITMENTS AND CONTINGENCIES66

COMMITMENTS AND CONTINGENCIES (Details) - ONEOK Partners [Member] $ in Millions	Dec. 31, 2015USD ($)
Firm Transportation and Storage Contracts [Abstract]
2,016	$ 45.8
2,017	42.1
2,018	40.6
2,019	36.2
2,020	35.8
Thereafter	47.9
Total	$ 248.4

SEGMENTS (Details)

SEGMENTS (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]
Segment Reporting, Disclosure of Major Customers									For the year ended December 31, 2015, we had no single customer from which we received 10 percent or more of our consolidated revenues.	For the year ended December 31, 2014, we had no single customer from which we received 10 percent or more of our consolidated revenues.	For the year ended December 31, 2013, we had no single customer from which we received 10 percent or more of our consolidated revenues.
Revenues	$ 1,930,384	$ 1,898,418	$ 2,127,507	$ 1,804,759	$ 2,844,258	$ 3,119,369	$ 3,065,735	$ 3,162,303	$ 7,761,068	$ 12,191,665	$ 11,869,273
Cost of sales and fuel (exclusive of items shown separately below)									5,641,052	10,088,548	10,222,213
Operating costs									692,176	669,657	521,513
Depreciation and amortization									352,196	291,236	236,743
Impairment of long-lived assets									83,673	0	0
Gain (loss) on sale of assets									6,108	6,599	11,881
Operating income									998,079	1,148,823	900,685
Equity in net earnings from investments									125,300	117,415	110,517
Impairment of equity method investments									(180,583)	(76,412)	0
Investments in unconsolidated affiliates	948,221				1,132,653				948,221	1,132,653	1,229,838
Total assets	14,927,586				14,600,400				14,927,586	14,600,400	12,824,160
Noncontrolling interests in consolidated subsidiaries	164,125				167,937				164,125	167,937	4,536
Capital expenditures									1,186,123	1,745,990	1,939,326
Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Revenues									1,837,116	2,967,608	2,051,482
Cost of sales and fuel (exclusive of items shown separately below)									1,265,617	2,305,723	1,550,855
Operating costs									272,418	257,658	193,293
Depreciation and amortization									150,008	123,847	103,962
Impairment of long-lived assets									73,681
Gain (loss) on sale of assets									2,775	219	436
Operating income									78,167	280,599	203,808
Equity in net earnings from investments									17,863	20,271	23,493
Impairment of equity method investments									(180,583)	(76,412)
Investments in unconsolidated affiliates	73,920				254,818				73,920	254,818	333,179
Total assets	5,123,450				4,911,283				5,123,450	4,911,283	3,949,813
Noncontrolling interests in consolidated subsidiaries	4,041				4,251				4,041	4,251	4,521
Capital expenditures									887,938	898,896	774,379
Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Revenues									6,579,699	10,545,381	10,778,027
Cost of sales and fuel (exclusive of items shown separately below)									5,328,256	9,435,296	9,908,089
Operating costs									314,505	296,402	236,638
Depreciation and amortization									158,709	124,071	89,240
Impairment of long-lived assets									9,992
Gain (loss) on sale of assets									(939)	(572)	843
Operating income									767,298	689,040	544,903
Equity in net earnings from investments									38,696	27,326	21,978
Impairment of equity method investments									0	0
Investments in unconsolidated affiliates	482,672				490,582				482,672	490,582	491,856
Total assets	8,017,799				8,143,575				8,017,799	8,143,575	6,938,633
Noncontrolling interests in consolidated subsidiaries	160,084				163,671				160,084	163,671	0
Capital expenditures									226,135	798,048	1,128,345
Natural Gas Liquids [Member] | Natural Gas Liquids Regulated [Member]
Segment Reporting Information [Line Items]
Revenues									954,800	695,900	534,800
Cost of sales and fuel (exclusive of items shown separately below)									412,600	309,400	207,400
Operating income									306,900	196,100	190,500
Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Revenues									332,447	350,456	325,514
Cost of sales and fuel (exclusive of items shown separately below)									34,481	21,935	39,795
Operating costs									105,720	111,037	101,182
Depreciation and amortization									43,479	43,318	43,541
Impairment of long-lived assets									0
Gain (loss) on sale of assets									4,272	6,786	10,602
Operating income									153,039	180,952	151,598
Equity in net earnings from investments									68,741	69,818	65,046
Impairment of equity method investments									0	0
Investments in unconsolidated affiliates	391,629				387,253				391,629	387,253	404,803
Total assets	1,844,401				1,823,713				1,844,401	1,823,713	1,817,445
Noncontrolling interests in consolidated subsidiaries	0				0				0	0	0
Capital expenditures									58,215	42,991	34,699
Natural Gas Pipelines [Member] | Natural Gas Pipelines Regulated [Member]
Segment Reporting Information [Line Items]
Revenues									266,900	290,000	246,900
Cost of sales and fuel (exclusive of items shown separately below)									31,100	47,700	29,300
Operating income									103,700	106,500	90,500
Other and Eliminations
Segment Reporting Information [Line Items]
Revenues									(988,194)	(1,671,780)	(1,285,750)
Cost of sales and fuel (exclusive of items shown separately below)									(987,302)	(1,674,406)	(1,276,526)
Operating costs									(467)	4,560	(9,600)
Depreciation and amortization									0	0	0
Impairment of long-lived assets									0
Gain (loss) on sale of assets									0	166	0
Operating income									(425)	(1,768)	376
Equity in net earnings from investments									0	0	0
Impairment of equity method investments									0	0
Investments in unconsolidated affiliates	0				0				0	0	0
Total assets	(58,064)				(278,171)				(58,064)	(278,171)	118,269
Noncontrolling interests in consolidated subsidiaries	$ 0				$ 15				0	15	15
Capital expenditures									13,835	6,055	1,903
Unaffiliated entity [Member]
Segment Reporting Information [Line Items]
Revenues									7,761,068	12,138,139	11,528,530
Unaffiliated entity [Member] | Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Revenues									1,187,390	1,478,729	665,169
Unaffiliated entity [Member] | Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Revenues									6,248,002	10,329,609	10,644,117
Unaffiliated entity [Member] | Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Revenues									325,676	329,801	219,244
Unaffiliated entity [Member] | Other and Eliminations
Segment Reporting Information [Line Items]
Revenues									0	0	0
Affiliated Entity [Member]
Segment Reporting Information [Line Items]
Revenues										53,526	340,743
Affiliated Entity [Member] | Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Revenues										41,214	238,600
Affiliated Entity [Member] | Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Revenues										0	0
Affiliated Entity [Member] | Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Revenues										12,312	102,143
Affiliated Entity [Member] | Other and Eliminations
Segment Reporting Information [Line Items]
Revenues										0	0
Operating Segments [Member]
Segment Reporting Information [Line Items]
Revenues									0	0	0
Operating Segments [Member] | Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Revenues									649,726	1,447,665	1,147,713
Operating Segments [Member] | Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Revenues									331,697	215,772	133,910
Operating Segments [Member] | Natural Gas Liquids [Member] | Natural Gas Liquids Regulated [Member]
Segment Reporting Information [Line Items]
Revenues									770,100	598,100	449,900
Operating Segments [Member] | Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Revenues									6,771	8,343	4,127
Operating Segments [Member] | Other and Eliminations
Segment Reporting Information [Line Items]
Revenues									(988,194)	$ (1,671,780)	$ (1,285,750)
Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Impairment of long-lived assets									$ 63,500

QUARTERLY FINANCIAL DATA (UNA68

QUARTERLY FINANCIAL DATA (UNAUDITED) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Impairment charges									$ 264,256	$ 76,412	$ 0
Revenues	$ 1,930,384	$ 1,898,418	$ 2,127,507	$ 1,804,759	$ 2,844,258	$ 3,119,369	$ 3,065,735	$ 3,162,303	7,761,068	12,191,665	11,869,273
Net income	9,565	229,665	211,610	147,032	264,036	167,320	214,511	265,468	597,872	911,335	803,983
Net income attributable to ONEOK Partners, L.P.	$ 7,217	$ 226,961	$ 209,770	$ 145,594	$ 263,225	$ 167,247	$ 214,434	$ 265,392	$ 589,542	$ 910,298	$ 803,626
Limited partners' per unit net income	$ (0.33)	$ 0.45	$ 0.44	$ 0.21	$ 0.67	$ 0.32	$ 0.54	$ 0.81	$ 0.73	$ 2.33	$ 2.35

SUPPLEMENTAL CONDENSED CONSOL69

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION CONDENSED CONSOLIDATING FINANCIAL STATEMENTS, Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Commodity sales									$ 6,098,343	$ 10,724,981	$ 10,549,157
Services									1,662,725	1,466,684	1,320,116
Total revenues	$ 1,930,384	$ 1,898,418	$ 2,127,507	$ 1,804,759	$ 2,844,258	$ 3,119,369	$ 3,065,735	$ 3,162,303	7,761,068	12,191,665	11,869,273
Cost of sales and fuel (exclusive of items shown separately below)									5,641,052	10,088,548	10,222,213
Operations and maintenance									609,123	599,076	464,633
Depreciation and amortization									352,196	291,236	236,743
General taxes									83,053	70,581	56,880
Gain (loss) on sale of assets									6,108	6,599	11,881
Operating income									998,079	1,148,823	900,685
Equity in net earnings from investments									125,300	117,415	110,517
Impairment of equity method investments									(180,583)	(76,412)	0
Interest expense									(338,911)	(281,908)	(236,714)
Income before income taxes									602,016	924,003	814,841
Income taxes									(4,144)	(12,668)	(10,858)
Net income	9,565	229,665	211,610	147,032	264,036	167,320	214,511	265,468	597,872	911,335	803,983
Less: Net income attributable to noncontrolling interests									8,330	1,037	357
Net income attributable to ONEOK Partners, L.P.	$ 7,217	$ 226,961	$ 209,770	$ 145,594	$ 263,225	$ 167,247	$ 214,434	$ 265,392	589,542	910,298	803,626
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Commodity sales									0	0	0
Services									0	0	0
Total revenues									0	0	0
Cost of sales and fuel (exclusive of items shown separately below)									0	0	0
Impairment of long-lived assets									0
Operating expenses									0	0	0
Gain (loss) on sale of assets									0	0	0
Operating income									0	0	0
Equity in net earnings from investments									589,500	910,300	803,600
Impairment of equity method investments									0	0
Other income (expense), net									371,000	331,700	287,600
Interest expense									(371,000)	(331,700)	(287,600)
Income before income taxes									589,500	910,300	803,600
Income taxes									0	0	0
Net income									589,500	910,300	803,600
Less: Net income attributable to noncontrolling interests									0	0	0
Net income attributable to ONEOK Partners, L.P.									589,500	910,300	803,600
Guarantor Subsidiary [Member]
Condensed Financial Statements, Captions [Line Items]
Commodity sales									0	0	0
Services									0	0	0
Total revenues									0	0	0
Cost of sales and fuel (exclusive of items shown separately below)									0	0	0
Impairment of long-lived assets									0
Operating expenses									0	0	0
Gain (loss) on sale of assets									0	0	0
Operating income									0	0	0
Equity in net earnings from investments									589,500	910,300	803,600
Impairment of equity method investments									0	0
Other income (expense), net									371,000	331,700	287,600
Interest expense									(371,000)	(331,700)	(287,600)
Income before income taxes									589,500	910,300	803,600
Income taxes									0	0	0
Net income									589,500	910,300	803,600
Less: Net income attributable to noncontrolling interests									0	0	0
Net income attributable to ONEOK Partners, L.P.									589,500	910,300	803,600
Combined Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Commodity sales									6,098,300	10,725,000	10,549,200
Services									1,662,800	1,466,700	1,320,100
Total revenues									7,761,100	12,191,700	11,869,300
Cost of sales and fuel (exclusive of items shown separately below)									5,641,100	10,088,600	10,222,200
Impairment of long-lived assets									83,700
Operating expenses									1,044,300	960,900	758,300
Gain (loss) on sale of assets									6,100	6,600	11,900
Operating income									998,100	1,148,800	900,700
Equity in net earnings from investments									58,400	47,600	45,500
Impairment of equity method investments									(180,600)	(76,400)
Other income (expense), net									(1,900)	16,100	40,300
Interest expense									(338,900)	(281,900)	(236,700)
Income before income taxes									535,100	854,200	749,800
Income taxes									(4,100)	(12,700)	(10,800)
Net income									531,000	841,500	739,000
Less: Net income attributable to noncontrolling interests									8,400	1,000	400
Net income attributable to ONEOK Partners, L.P.									522,600	840,500	738,600
Consolidating Entries [Member]
Condensed Financial Statements, Captions [Line Items]
Commodity sales									0	0	0
Services									0	0	0
Total revenues									0	0	0
Cost of sales and fuel (exclusive of items shown separately below)									0	0	0
Impairment of long-lived assets									0
Operating expenses									0	0	0
Gain (loss) on sale of assets									0	0	0
Operating income									0	0	0
Equity in net earnings from investments									(1,112,100)	(1,750,800)	(1,542,200)
Impairment of equity method investments									0	0
Other income (expense), net									(742,000)	(663,400)	(575,200)
Interest expense									742,000	663,400	575,200
Income before income taxes									(1,112,100)	(1,750,800)	(1,542,200)
Income taxes									0	0	0
Net income									(1,112,100)	(1,750,800)	(1,542,200)
Less: Net income attributable to noncontrolling interests									0	0	0
Net income attributable to ONEOK Partners, L.P.									(1,112,100)	(1,750,800)	(1,542,200)
Total [Member]
Condensed Financial Statements, Captions [Line Items]
Commodity sales									6,098,300	10,725,000	10,549,200
Services									1,662,800	1,466,700	1,320,100
Total revenues									7,761,100	12,191,700	11,869,300
Cost of sales and fuel (exclusive of items shown separately below)									5,641,100	10,088,600	10,222,200
Impairment of long-lived assets									83,700
Operating expenses									1,044,300	960,900	758,300
Gain (loss) on sale of assets									6,100	6,600	11,900
Operating income									998,100	1,148,800	900,700
Equity in net earnings from investments									125,300	117,400	110,500
Impairment of equity method investments									(180,600)	(76,400)
Other income (expense), net									(1,900)	16,100	40,300
Interest expense									(338,900)	(281,900)	(236,700)
Income before income taxes									602,000	924,000	814,800
Income taxes									(4,100)	(12,700)	(10,800)
Net income									597,900	911,300	804,000
Less: Net income attributable to noncontrolling interests									8,400	1,000	400
Net income attributable to ONEOK Partners, L.P.									$ 589,500	$ 910,300	803,600
Northern Border Pipeline [Member]
Condensed Financial Statements, Captions [Line Items]
Equity Method Investment, Ownership Percentage	50.00%				50.00%				50.00%	50.00%
Equity in net earnings from investments									$ 66,941	$ 69,819	$ 65,046

SUPPLEMENTAL CONDENSED CONSOL70

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION CONDENSED CONSOLIDATING FINANCIAL INFORMATION, Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Condensed Financial Statements, Captions [Line Items]
Net income	$ 9,565	$ 229,665	$ 211,610	$ 147,032	$ 264,036	$ 167,320	$ 214,511	$ 265,468	$ 597,872	$ 911,335	$ 803,983
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives									45,575	(64,639)	32,141
Realized (gains) losses on derivatives recognized in net income									(67,034)	31,653	8,344
Total other comprehensive income (loss)									(21,459)	(32,986)	40,485
Comprehensive income									576,413	878,349	844,468
Less: Comprehensive income attributable to noncontrolling interests									8,330	1,037	357
Comprehensive income attributable to ONEOK Partners, L.P.									568,083	877,312	844,111
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net income									589,500	910,300	803,600
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives									45,600	(64,600)	32,100
Realized (gains) losses on derivatives recognized in net income									(67,000)	31,600	8,400
Total other comprehensive income (loss)									(21,400)	(33,000)	40,500
Comprehensive income									568,100	877,300	844,100
Less: Comprehensive income attributable to noncontrolling interests									0	0	0
Comprehensive income attributable to ONEOK Partners, L.P.									568,100	877,300	844,100
Guarantor Subsidiary [Member]
Condensed Financial Statements, Captions [Line Items]
Net income									589,500	910,300	803,600
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives									68,100	32,400	(14,500)
Realized (gains) losses on derivatives recognized in net income									(81,100)	21,100	(1,700)
Total other comprehensive income (loss)									(13,000)	53,500	(16,200)
Comprehensive income									576,500	963,800	787,400
Less: Comprehensive income attributable to noncontrolling interests									0	0	0
Comprehensive income attributable to ONEOK Partners, L.P.									576,500	963,800	787,400
Combined Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net income									531,000	841,500	739,000
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives									68,100	32,400	(14,500)
Realized (gains) losses on derivatives recognized in net income									(81,100)	21,100	(1,700)
Total other comprehensive income (loss)									(13,000)	53,500	(16,200)
Comprehensive income									518,000	895,000	722,800
Less: Comprehensive income attributable to noncontrolling interests									8,400	1,000	400
Comprehensive income attributable to ONEOK Partners, L.P.									509,600	894,000	722,400
Consolidating Entries [Member]
Condensed Financial Statements, Captions [Line Items]
Net income									(1,112,100)	(1,750,800)	(1,542,200)
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives									(136,200)	(64,800)	29,000
Realized (gains) losses on derivatives recognized in net income									162,200	(42,200)	3,400
Total other comprehensive income (loss)									26,000	(107,000)	32,400
Comprehensive income									(1,086,100)	(1,857,800)	(1,509,800)
Less: Comprehensive income attributable to noncontrolling interests									0	0	0
Comprehensive income attributable to ONEOK Partners, L.P.									(1,086,100)	(1,857,800)	(1,509,800)
Total [Member]
Condensed Financial Statements, Captions [Line Items]
Net income									597,900	911,300	804,000
Other comprehensive income (loss)
Unrealized gains (losses) on derivatives									45,600	(64,600)	32,100
Realized (gains) losses on derivatives recognized in net income									(67,000)	31,600	8,400
Total other comprehensive income (loss)									(21,400)	(33,000)	40,500
Comprehensive income									576,500	878,300	844,500
Less: Comprehensive income attributable to noncontrolling interests									8,400	1,000	400
Comprehensive income attributable to ONEOK Partners, L.P.									$ 568,100	$ 877,300	$ 844,100

SUPPLEMENTAL CONDENSED CONSOL71

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION CONDENSED CONSOLIDATING FINANCIAL STATEMENTS, Balance Sheet (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Current assets
Cash and cash equivalents	$ 5,079	$ 42,530	$ 134,530	$ 537,074
Accounts receivable, net	593,448	735,830
Affiliate receivables	7,969	8,553
Natural gas and natural gas liquids in storage	128,084	134,134
Commodity imbalances	38,681	64,788
Materials and supplies	76,696	55,833
Other current assets	33,207	44,385
Total current assets	883,164	1,086,053
Property, plant and equipment
Property, plant and equipment	14,307,546	13,377,617
Accumulated depreciation and amortization	2,050,755	1,842,084
Net property, plant and equipment	12,256,791	11,535,533
Investments and other assets
Investments in unconsolidated affiliates	948,221	1,132,653	1,229,838
Goodwill and intangible assets	824,877	822,358
Other assets	14,533	23,803
Total investments and other assets	1,787,631	1,978,814
Total assets	14,927,586	14,600,400	12,824,160
Current liabilities
Current maturities of long-term debt	107,650	7,650
Short-term borrowings	546,340	1,055,296
Accounts payable	605,431	874,692
Affiliate payables	27,137	36,106
Commodity imbalances	74,460	104,650
Accrued interest	102,615	91,990
Other current liabilities	116,667	165,672
Total current liabilities	1,580,300	2,336,056
Long-term debt, excluding current maturities	6,695,312	6,004,232
Deferred credits and other liabilities	$ 154,631	$ 141,337
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consoldated subsidiaries	$ 6,333,218	$ 5,950,838
Noncontrolling interests in consolidated subsidiaries	164,125	167,937	4,536
Total equity	6,497,343	6,118,775
Total liabilities and equity	14,927,586	14,600,400
Parent Company [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
Materials and supplies	0	0
Other current assets	4,100	1,900
Total current assets	4,100	1,900
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	10,144,900	8,843,300
Other assets	3,594,000	4,250,100
Total investments and other assets	13,738,900	13,093,400
Total assets	13,743,000	13,095,300
Current liabilities
Current maturities of long-term debt	100,000	0
Short-term borrowings	546,300	1,055,300
Accounts payable	0	0
Affiliate payables	0	0
Other current liabilities	112,500	136,800
Total current liabilities	758,800	1,192,100
Intercompany debt	0	0
Long-term debt, excluding current maturities	6,651,000	5,952,400
Deferred credits and other liabilities	$ 0	$ 0
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consoldated subsidiaries	$ 6,333,200	$ 5,950,800
Noncontrolling interests in consolidated subsidiaries	0	0
Total equity	6,333,200	5,950,800
Total liabilities and equity	13,743,000	13,095,300
Guarantor Subsidiary [Member]
Current assets
Cash and cash equivalents	5,100	42,500	134,500	537,100
Accounts receivable, net	0	0
Affiliate receivables	0	0
Natural gas and natural gas liquids in storage	0	0
Materials and supplies	0	0
Other current assets	0	0
Total current assets	5,100	42,500
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	7,781,800	7,579,000
Other assets	5,952,000	5,469,800
Total investments and other assets	13,733,800	13,048,800
Total assets	13,738,900	13,091,300
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	10,144,900	8,843,300
Long-term debt, excluding current maturities	0	0
Deferred credits and other liabilities	$ 0	$ 0
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consoldated subsidiaries	$ 3,594,000	$ 4,248,000
Noncontrolling interests in consolidated subsidiaries	0	0
Total equity	3,594,000	4,248,000
Total liabilities and equity	13,738,900	13,091,300
Combined Non-Guarantor Subsidiaries [Member]
Current assets
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	593,400	735,800
Affiliate receivables	8,000	8,600
Natural gas and natural gas liquids in storage	128,100	134,100
Materials and supplies	76,700	55,800
Other current assets	67,800	107,300
Total current assets	874,000	1,041,600
Property, plant and equipment
Property, plant and equipment	14,307,500	13,377,600
Accumulated depreciation and amortization	2,050,700	1,842,100
Net property, plant and equipment	12,256,800	11,535,500
Investments and other assets
Intercompany notes receivable	0	0
Other assets	1,425,200	1,590,300
Total investments and other assets	1,425,200	1,590,300
Total assets	14,556,000	14,167,400
Current liabilities
Current maturities of long-term debt	7,700	7,700
Short-term borrowings	0	0
Accounts payable	605,400	874,700
Affiliate payables	27,100	36,100
Other current liabilities	181,400	225,500
Total current liabilities	821,600	1,144,000
Intercompany debt	7,781,800	7,579,000
Long-term debt, excluding current maturities	44,300	51,900
Deferred credits and other liabilities	$ 154,600	$ 141,300
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consoldated subsidiaries	$ 5,589,600	$ 5,083,300
Noncontrolling interests in consolidated subsidiaries	164,100	167,900
Total equity	5,753,700	5,251,200
Total liabilities and equity	14,556,000	14,167,400
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
Materials and supplies	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	(17,926,700)	(16,422,300)
Other assets	(9,183,600)	(9,331,300)
Total investments and other assets	(27,110,300)	(25,753,600)
Total assets	(27,110,300)	(25,753,600)
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	(17,926,700)	(16,422,300)
Long-term debt, excluding current maturities	0	0
Deferred credits and other liabilities	$ 0	$ 0
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consoldated subsidiaries	$ (9,183,600)	$ (9,331,300)
Noncontrolling interests in consolidated subsidiaries	0	0
Total equity	(9,183,600)	(9,331,300)
Total liabilities and equity	(27,110,300)	(25,753,600)
Total [Member]
Current assets
Cash and cash equivalents	5,100	42,500	$ 134,500	$ 537,100
Accounts receivable, net	593,400	735,800
Affiliate receivables	8,000	8,600
Natural gas and natural gas liquids in storage	128,100	134,100
Materials and supplies	76,700	55,800
Other current assets	71,900	109,200
Total current assets	883,200	1,086,000
Property, plant and equipment
Property, plant and equipment	14,307,500	13,377,600
Accumulated depreciation and amortization	2,050,700	1,842,100
Net property, plant and equipment	12,256,800	11,535,500
Investments and other assets
Intercompany notes receivable	0	0
Other assets	1,787,600	1,978,900
Total investments and other assets	1,787,600	1,978,900
Total assets	14,927,600	14,600,400
Current liabilities
Current maturities of long-term debt	107,700	7,700
Short-term borrowings	546,300	1,055,300
Accounts payable	605,400	874,700
Affiliate payables	27,100	36,100
Other current liabilities	293,900	362,300
Total current liabilities	1,580,400	2,336,100
Intercompany debt	0	0
Long-term debt, excluding current maturities	6,695,300	6,004,300
Deferred credits and other liabilities	$ 154,600	$ 141,300
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consoldated subsidiaries	$ 6,333,200	$ 5,950,800
Noncontrolling interests in consolidated subsidiaries	164,100	167,900
Total equity	6,497,300	6,118,700
Total liabilities and equity	$ 14,927,600	$ 14,600,400

SUPPLEMENTAL CONDENSED CONSOL72

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION CONDENSED CONSOLIDATING FINANCIAL STATEMENTS, Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating activities
Cash provided by operating activities	$ 1,071,980	$ 1,309,820	$ 1,007,731
Investing activities
Acquisitions	0	(814,934)	(394,889)
Payments to Acquire Other Investments	(27,540)	(1,063)	(35,308)
Distributions received from unconsolidated affiliates in excess of cumulative earnings	33,915	21,107	31,134
Capital expenditures	(1,186,123)	(1,745,990)	(1,939,326)
Other investing activities	(12,607)	0	0
Cash Provided by (used in) Investing Activities	(1,188,530)	(2,533,063)	(2,326,099)
Financing activities
Cash distributions paid to general and limited partners	(1,230,475)	(1,052,245)	(909,713)
Cash distributions paid to noncontrolling interests	(11,690)	(549)	(588)
Issuance of long-term debt, net of discounts	798,896	0	1,247,822
Debt financing costs	(7,676)	0	(10,246)
Repayments of long-term debt	(7,650)	(7,650)	(7,650)
Issuance of common units, net of issuance costs	1,025,660	1,113,139	583,929
Contribution from general partner	20,990	23,252	12,270
Cash provided by (used in) financing activities	79,099	1,131,243	915,824
Change in cash and cash equivalents	(37,451)	(92,000)	(402,544)
Cash and cash equivalents at beginning of period	42,530	134,530	537,074
Cash and cash equivalents at end of period	5,079	42,530	134,530
Parent Company [Member]
Operating activities
Cash provided by operating activities	1,196,700	1,155,700	870,700
Investing activities
Capital expenditures	0	0	0
Other investing activities	0	0	0
Cash Provided by (used in) Investing Activities	0	0	0
Financing activities
Cash distributions paid to general and limited partners	(1,230,500)	(1,052,200)	(909,700)
Cash distributions paid to noncontrolling interests	0	0	0
Intercompany borrowings (advances), net	(1,295,100)	(2,295,200)	(1,794,800)
Borrowing (repayment) of short-term borrowings, net	(509,000)	1,055,300
Issuance of long-term debt, net of discounts	798,900		1,247,800
Debt financing costs	(7,700)		(10,200)
Repayments of long-term debt	0	0	0
Issuance of common units, net of issuance costs	1,025,700	1,113,100	583,900
Contribution from general partner	21,000	23,300	12,300
Cash provided by (used in) financing activities	(1,196,700)	(1,155,700)	(870,700)
Change in cash and cash equivalents	0	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	66,900	69,800	65,100
Investing activities
Capital expenditures	0	0	(2,600)
Other investing activities	24,100	17,700	(11,400)
Cash Provided by (used in) Investing Activities	24,100	17,700	(14,000)
Financing activities
Cash distributions paid to general and limited partners	(1,230,500)	(1,052,200)	(909,700)
Cash distributions paid to noncontrolling interests	0	0	0
Intercompany borrowings (advances), net	1,102,100	872,700	456,000
Borrowing (repayment) of short-term borrowings, net	0	0
Issuance of long-term debt, net of discounts	0		0
Debt financing costs	0		0
Repayments of long-term debt	0	0	0
Issuance of common units, net of issuance costs	0	0	0
Contribution from general partner	0	0	0
Cash provided by (used in) financing activities	(128,400)	(179,500)	(453,700)
Change in cash and cash equivalents	(37,400)	(92,000)	(402,600)
Cash and cash equivalents at beginning of period	42,500	134,500	537,100
Cash and cash equivalents at end of period	5,100	42,500	134,500
Combined Non-Guarantor Subsidiaries [Member]
Operating activities
Cash provided by operating activities	1,038,900	1,136,500	981,600
Investing activities
Capital expenditures	(1,186,100)	(1,746,000)	(1,936,700)
Other investing activities	(26,500)	(804,700)	(375,400)
Cash Provided by (used in) Investing Activities	(1,212,600)	(2,550,700)	(2,312,100)
Financing activities
Cash distributions paid to general and limited partners	0	0	0
Cash distributions paid to noncontrolling interests	(11,700)	(600)	(600)
Intercompany borrowings (advances), net	193,000	1,422,500	1,338,800
Borrowing (repayment) of short-term borrowings, net	0	0
Issuance of long-term debt, net of discounts	0		0
Debt financing costs	0		0
Repayments of long-term debt	(7,600)	(7,700)	(7,700)
Issuance of common units, net of issuance costs	0	0	0
Contribution from general partner	0	0	0
Cash provided by (used in) financing activities	173,700	1,414,200	1,330,500
Change in cash and cash equivalents	0	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	(1,230,500)	(1,052,200)	(909,700)
Investing activities
Capital expenditures	0	0	0
Other investing activities	0	0	0
Cash Provided by (used in) Investing Activities	0	0	0
Financing activities
Cash distributions paid to general and limited partners	1,230,500	1,052,200	909,700
Cash distributions paid to noncontrolling interests	0	0	0
Intercompany borrowings (advances), net	0	0	0
Borrowing (repayment) of short-term borrowings, net	0	0
Issuance of long-term debt, net of discounts	0		0
Debt financing costs	0		0
Repayments of long-term debt	0	0	0
Issuance of common units, net of issuance costs	0	0	0
Contribution from general partner	0	0	0
Cash provided by (used in) financing activities	1,230,500	1,052,200	909,700
Change in cash and cash equivalents	0	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	1,072,000	1,309,800	1,007,700
Investing activities
Capital expenditures	(1,186,100)	(1,746,000)	(1,939,300)
Other investing activities	(2,400)	(787,000)	(386,800)
Cash Provided by (used in) Investing Activities	(1,188,500)	(2,533,000)	(2,326,100)
Financing activities
Cash distributions paid to general and limited partners	(1,230,500)	(1,052,200)	(909,700)
Cash distributions paid to noncontrolling interests	(11,700)	(600)	(600)
Intercompany borrowings (advances), net	0	0	0
Borrowing (repayment) of short-term borrowings, net	(509,000)	1,055,300
Issuance of long-term debt, net of discounts	798,900		1,247,800
Debt financing costs	(7,700)		(10,200)
Repayments of long-term debt	(7,600)	(7,700)	(7,700)
Issuance of common units, net of issuance costs	1,025,700	1,113,100	583,900
Contribution from general partner	21,000	23,300	12,300
Cash provided by (used in) financing activities	79,100	1,131,200	915,800
Change in cash and cash equivalents	(37,400)	(92,000)	(402,600)
Cash and cash equivalents at beginning of period	42,500	134,500	537,100
Cash and cash equivalents at end of period	$ 5,100	$ 42,500	$ 134,500