ONEOK (OKE) 10-Q 1 Nov 17 2017 Q3 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
	Sep. 30, 2017	Oct. 23, 2017
Document Information [Line Items]
Entity Registrant Name	ONEOK INC /NEW/
Entity Central Index Key	1,039,684
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
Limited Partners' Capital Account, Units Outstanding		383,436,687
Document Fiscal Year Focus	2,017
Document Fiscal Period Focus	Q3
Document Type	10-Q
Amendment Flag	false
Document Period End Date	Sep. 30, 2017

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Revenues
Commodity sales	$ 2,322,534	$ 1,840,523	$ 6,700,260	$ 4,757,306
Services	583,832	517,384	1,681,489	1,509,167
Total revenues	2,906,366	2,357,907	8,381,749	6,266,473
Cost of sales and fuel (exclusive of items shown separately below)	2,229,416	1,751,593	6,464,281	4,474,654
Operations and maintenance	182,409	165,664	540,679	488,476
Depreciation and amortization	102,298	98,550	302,566	292,275
Impairment of long-lived assets	15,970	0	15,970	0
General taxes	24,641	18,487	76,098	64,529
Gain on sale of assets	(274)	(5,744)	(904)	(9,537)
Operating income	351,906	329,357	983,059	956,076
Equity in net earnings from investments (Note J)	40,058	35,155	118,985	100,441
Impairment of equity investments (Note J)	(4,270)	0	(4,270)	0
Allowance for equity funds used during construction	40	0	75	208
Other income	3,296	4,242	11,670	9,351
Other expense	(838)	(710)	(23,431)	(2,288)
Interest expense (net of capitalized interest of $1,068, $3,806, $4,254, and $9,265, respectively)	(126,533)	(118,240)	(361,468)	(355,463)
Income before income taxes	263,659	249,804	724,620	708,325
Income taxes	(97,128)	(55,012)	(195,913)	(157,536)
Income from continuing operations	166,531	194,792	528,707	550,789
Income (loss) from discontinued operations, net of tax	0	(576)	0	(1,755)
Net income	166,531	194,216	528,707	549,034
Less: Net income attributable to noncontrolling interests	789	102,072	203,911	287,500
Net income attributable to ONEOK	165,742	92,144	324,796	261,534
Less: Preferred stock dividends	276	0	493	0
Net income available to common shareholders	165,466	92,144	324,303	261,534
Amounts available to common shareholders:
Income from continuing operations	165,466	92,720	324,303	263,289
Income (loss) from discontinued operations	0	(576)	0	(1,755)
Net income available to common shareholders	$ 165,466	$ 92,144	$ 324,303	$ 261,534
Basic earnings per common share:
Income from continuing operations (Note H)	$ 0.43	$ 0.44	$ 1.21	$ 1.25
Income (loss) from discontinued operations	0	0	0	(0.01)
Net income	0.43	0.44	1.21	1.24
Diluted earnings per common share:
Income from continuing operations (Note H)	0.43	0.44	1.20	1.24
Income (loss) from discontinued operations	0	(0.01)	0	(0.01)
Net income	$ 0.43	$ 0.43	$ 1.20	$ 1.23
Average shares (thousands)
Basic	380,907	211,309	268,108	211,038
Diluted	383,419	212,870	270,349	212,123
Dividends declared per share of common stock	$ 0.745	$ 0.615	$ 1.975	$ 1.845

CONSOLIDATED STATEMENT OF INCOM

CONSOLIDATED STATEMENT OF INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Interest expense (net of capitalized interest)	$ 1,068	$ 3,806	$ 4,254	$ 9,265

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Net income	$ 166,531	$ 194,216	$ 528,707	$ 549,034
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on derivatives, net of tax of $12,217, $(1,301), $8,689 and $15,033, respectively	(20,620)	7,237	(1,287)	(83,580)
Realized (gains) losses on derivatives recognized in net income, net of tax of $(7,671), $(811), $(13,077) and $1,658, respectively	13,062	3,083	40,272	(13,496)
Change in pension and postretirement benefit plan liability, net of tax of $(1,360), $(1,035), $(4,081) and $(3,105) respectively.	2,041	1,553	6,122	4,658
Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax of $100, $108, $288 and $1,840, respectively	(169)	(600)	(1,214)	(10,231)
Total other comprehensive income (loss), net of tax	(5,686)	11,273	43,893	(102,649)
Comprehensive income	160,845	205,489	572,600	446,385
Less: Comprehensive income attributable to noncontrolling interests	789	108,450	234,937	211,960
Comprehensive income attributable to ONEOK	$ 160,056	$ 97,039	$ 337,663	$ 234,425

CONSOLIDATED STATEMENTS OF COM5

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (PARANTHETICAL) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Unrealized Gains (Losses) on Derivatives, Tax	$ 12,217	$ (1,301)	$ 8,689	$ 15,033
Realized (Gains) Losses on Derivatives in Net Income, Tax	(7,671)	(811)	(13,077)	1,658
Change in Pension and Postretirement Benefit Plan Liability, Tax	(1,360)	(1,035)	(4,081)	(3,105)
Other Comprehensive Income (Loss) on Investments in Unconsolidated Affiliates, Tax	$ 100	$ 108	$ 288	$ 1,840

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current assets
Cash and cash equivalents	$ 11,676	$ 248,875
Accounts receivable, net	939,595	872,430
Materials and supplies	77,366	60,912
Natural gas and natural gas liquids in storage	314,266	140,034
Commodity imbalances	111,766	60,896
Other current assets	64,196	45,986
Asset of discontinued operations	0	551
Total current assets	1,518,865	1,429,684
Property, plant and equipment
Property, plant and equipment	15,364,289	15,078,497
Accumulated depreciation and amortization	2,785,682	2,507,094
Net property, plant and equipment	12,578,607	12,571,403
Investments and other assets
Investments in unconsolidated affiliates	1,013,702	958,807
Goodwill and intangible assets	996,435	1,005,359
Deferred Income Taxes	474,967	0
Other assets	182,265	162,998
Asset of discontinued operations	0	10,500
Total investments and other assets	2,667,369	2,137,664
Total assets	16,764,841	16,138,751
Current liabilities
Current maturities of long-term debt (Note E)	432,650	410,650
Short-term borrowings (Note E)	932,250	1,110,277
Accounts payable	922,820	874,731
Commodity imbalances	189,512	142,646
Accrued interest	97,023	112,514
Other current liabilities	166,825	166,042
Liabilities of discontinued operations	0	19,841
Total current liabilities	2,741,080	2,836,701
Long-term debt, excluding current maturities (Note E)	8,092,000	7,919,996
Deferred income taxes	76,262	1,623,822
Other deferred credits	339,116	321,846
Liabilities of discontinued operations	0	7,471
Total deferred credits and other liabilities	415,378	1,953,139
Commitments and contingencies (Note K)
Equity (Note F)
Preferred stock, $0.01 par value: issued 20,000 shares at September 30, 2017, and no shares at December 31, 2016	0	0
Common stock, $0.01 par value :authorized 1,200,000,000 shares, issued 415,913,504 shares and outstanding 381,285,028 shares at September 30, 2017; authorized 600,000,000 shares, issued 245,811,180 shares and outstanding 210,681,661 shares at December 31, 2016	4,159	2,458
Paid in Capital	6,418,038	1,234,314
Accumulated other comprehensive loss (Note G)	(181,771)	(154,350)
Retained Earnings	0	0
Treasury stock, at cost: 34,628,476 shares at September 30, 2017, and 35,129,519 shares at December 31, 2016	(880,931)	(893,677)
Total ONEOK Shareholder' Equity	5,359,495	188,745
Noncontrolling interests in consolidated subsidiaries	156,888	3,240,170
Total equity	5,516,383	3,428,915
Total liabilities and equity	$ 16,764,841	$ 16,138,751

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2017	Dec. 31, 2016
Equity (Note F)
Common Stock, Par or Stated Value Per Share	$ 0.01	$ 0.01
Common Stock, Shares, Issued	415,913,504	245,811,180
Common Stock, Shares Authorized	1,200,000,000	600,000,000
Common Stock, Shares, Outstanding	381,285,028	210,681,661
Treasury Stock, Shares	34,628,476	35,129,519
Preferred Stock, Par or Stated Value Per Share	$ 0.01	$ 0
Preferred Stock, Shares Issued	20,000	0

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating activities
Net income	$ 528,707	$ 549,034
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	302,566	292,275
Impairment Charges	20,240	0
Noncash contribution of preferred stock, net of tax	12,600	0
Equity in net earnings from investments	(118,985)	(100,441)
Distributions received from unconsolidated affiliates	124,517	106,381
Deferred income taxes	186,584	157,819
Share-based compensation expense	19,688	31,112
Pension and postretirement benefit expense, net of contributions	818	8,270
Allowance for equity funds used during construction	(75)	(208)
Gain on sale of assets	(904)	(9,537)
Changes in assets and liabilities:
Accounts receivable	(33,224)	(145,430)
Natural gas and natural gas liquids in storage	(174,232)	(89,685)
Accounts payable	82,174	138,198
Commodity imbalances, net	(4,004)	55,109
Settlement of exit activities liabilities	(8,127)	(16,211)
Accrued interest	(15,491)	(24,906)
Risk-management assets and liabilities	34,534	(48,695)
Other assets and liabilities, net	(21,390)	18,943
Cash provided by operating activities	935,996	922,028
Investing activities
Capital expenditures (less allowance for equity funds used during construction)	(330,431)	(491,528)
Contributions to unconsolidated affiliates	(87,653)	(55,177)
Distributions received from unconsolidated affiliates in excess of cumulative earnings	21,577	43,018
Proceeds from sale of assets	1,910	19,099
Cash used in investing activities	(394,597)	(484,588)
Financing activities
Dividends paid	(543,445)	(388,103)
Distributions to noncontrolling interests	(275,060)	(412,539)
Borrowing (repayment) of short-term borrowings, net	(178,027)	147,160
Issuance of long-term debt, net of discounts	1,190,067	1,000,000
Debt financing costs	(11,340)	(2,770)
Repayment of long-term debt	(992,864)	(656,117)
Issuance of common stock	45,849	14,948
Other	(13,778)	0
Cash used in financing activities	(778,598)	(297,421)
Change in cash and cash equivalents	(237,199)	140,019
Change in cash and cash equivalents included in discontinued operations	0	(228)
Change in cash and cash equivalents from continuing operations	(237,199)	139,791
Cash and cash equivalents at beginning of period	248,875	97,619
Cash and cash equivalents at end of period	$ 11,676	$ 237,410

CONSOLIDATED STATEMENT OF CHANG

CONSOLIDATED STATEMENT OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Preferred Stock [Member]	Additional Paid-in Capital [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Retained Earnings [Member]	Treasury Stock [Member]	Noncontrolling Interests in Consolidated Subsidiaries [Member]
Shares, issued, beginning balance at Dec. 31, 2015		245,811,180	0
Total equity, beginning balance at Dec. 31, 2015	$ 3,766,336	$ 2,458	$ 0	$ 1,378,444	$ (127,242)	$ 0	$ (917,862)	$ 3,430,538
Net income	549,034	0	0	0	0	261,534	0	287,500
Other comprehensive income (loss) (Note G)	(102,649)	0	0	0	(27,109)	0	0	(75,540)
Common Stock Issued	19,479	$ 0	0	(531)	0	0	20,010	0
Stock Issued During Period, Shares, Other		0
Common stock dividends	(388,103)	$ 0	0	(126,569)	0	(261,534)	0	0
Distributions to Noncontrolling Interests	(412,539)	0	0	0	0	0	0	(412,539)
Stockholders' Equity, Other	8,656	$ 0	$ 0	12,697	0	0	0	(4,041)
Shares, issued, ending balance at Sep. 30, 2016		245,811,180	0
Total equity, ending balance at Sep. 30, 2016	3,440,214	$ 2,458	$ 0	1,264,041	(154,351)	0	(897,852)	3,225,918
Cumulative effect adjustment for adoption of ASU 2016-09 at December 31, 2016	73,368	$ 0	$ 0	0	0	73,368	0	0
Shares, issued, beginning balance at Dec. 31, 2016		245,811,180	0
Total equity, beginning balance at Dec. 31, 2016	3,428,915	$ 2,458	$ 0	1,234,314	(154,350)	0	(893,677)	3,240,170
Net income	528,707	0	0	0	0	324,796	0	203,911
Other comprehensive income (loss) (Note G)	43,893	0	0	0	12,867	0	0	31,026
Common Stock Issued	80,790	$ 12	$ 0	68,032	0	0	12,746	0
Stock Issued During Period, Shares, Other		1,181,493	20,000
Preferred Stock Issued	20,000	$ 0	$ 0	20,000	0	0	0	0
Common stock dividends	(543,076)	0	0	(144,912)	0	(398,164)	0	0
Preferred stock dividends	(493)	0	0	(493)	0	0	0	0
Distributions to Noncontrolling Interests	(275,060)	$ 0	0	0	0	0	0	(275,060)
Stock Issued During Period, Shares, Acquisitions		168,920,831
Acquisition of ONEOK Partners’ noncontrolling interests (Note B)	2,146,462	$ 1,689	0	5,228,580	(40,288)	0	0	(3,043,519)
Stockholders' Equity, Other	12,877	$ 0	$ 0	12,517	0	0	0	360
Shares, issued, ending balance at Sep. 30, 2017		415,913,504	20,000
Total equity, ending balance at Sep. 30, 2017	$ 5,516,383	$ 4,159	$ 0	$ 6,418,038	$ (181,771)	$ 0	$ (880,931)	$ 156,888

CONSOLIDATED STATEMENT OF CHA10

CONSOLIDATED STATEMENT OF CHANGES IN EQUITY CONSOLIDATED STATEMENT OF CHANGES IN EQUITY Parenthetical - $ / shares	3 Months Ended			9 Months Ended
	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2017	Sep. 30, 2016
Statement of Stockholders' Equity [Abstract]
Dividends paid (in dollars per share)	$ 0.745	$ 0.615	$ 0.615	$ 1.975	$ 1.845

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Notes)	9 Months Ended
	Sep. 30, 2017
Accounting Policies [Abstract]
Significant Accounting Policies [Text Block]	SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES Our accompanying unaudited consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC. These statements have been prepared in accordance with GAAP and reflect all adjustments that, in our opinion, are necessary for a fair statement of the results for the interim periods presented. All such adjustments are of a normal recurring nature. The 2016 year-end consolidated balance sheet data was derived from our audited financial statements but does not include all disclosures required by GAAP. Certain reclassifications have been made in the prior-year financial statements to conform to the current-year presentation. These unaudited consolidated financial statements should be read in conjunction with our audited consolidated financial statements in our Annual Report and our Current Report on Form 8-K filed on July 6, 2017, which updates Item 8 in our Annual Report. Our significant accounting policies are consistent with those disclosed in Note A of the Notes to Consolidated Financial Statements in our Annual Report, except as described below. Merger Transaction - On June 30, 2017, we completed the acquisition of all of the outstanding common units of ONEOK Partners that we did not already own. See Note B for additional information, including a discussion of the impact of the Merger Transaction on our Consolidated Financial Statements. Discontinued Operations - Beginning in 2017, the results of operations and financial position of our former energy services business are no longer reflected as discontinued operations in our Consolidated Financial Statements and Notes to the Consolidated Financial Statements, as they are not material. Recently Issued Accounting Standards Update - Changes to GAAP are established by the Financial Accounting Standards Board (FASB) in the form of ASUs to the FASB Accounting Standards Codification. We consider the applicability and impact of all ASUs. ASUs not listed below were assessed and determined to be either not applicable or clarifications of ASUs listed below. The following tables provide a brief description of recent accounting pronouncements and our analysis of the effects on our financial statements: Standard Description Date of Adoption Effect on the Financial Statements or Other Significant Matters Standards that were adopted ASU 2015-11, “Inventory (Topic 330): Simplifying the Measurement of Inventory” The standard 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. First quarter 2017 As a result of adopting this guidance, we updated our accounting policy for inventory valuation accordingly. The financial impact of adopting this guidance was not material. ASU 2016-05, “Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships” The standard clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. First quarter 2017 The impact of adopting this standard was not material. ASU 2016-06, “Derivatives and Hedging (Topic 815): Contingent Put and Call Options in Debt Instruments” The standard clarifies the requirements for assessing whether a contingent call (put) option that can accelerate the payment of principal on a debt instrument is clearly and closely related to its debt host. First quarter 2017 The impact of adopting this standard was not material. ASU 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting” The standard provides simplified accounting for share-based payment transactions in relation to income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. First quarter 2017 As a result of adopting this guidance, we recorded an adjustment increasing beginning retained earnings and deferred tax assets in the first quarter 2017 of approximately $73 million to recognize previously unrecognized cumulative excess tax benefits related to share-based payments on a modified retrospective basis. Beginning in January 2017, all share-based payment tax effects are recorded in earnings. The other effects of adopting this standard were not material. Standard Description Date of Adoption Effect on the Financial Statements or Other Significant Matters Standards that are not yet adopted ASU 2014-09, “Revenue from Contracts with Customers (Topic 606)” The standard 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. First quarter 2018 We expect to adopt this standard on January 1, 2018, using the modified retrospective method. We have not completed our analysis to quantify the cumulative effect of adoption adjustment to retained earnings, but do not expect it to be material. For many of our contracts, we do not expect material changes in our accounting policies or revenue recognition. However, under Topic 606, we expect that a significant portion of services revenues will be presented as reduction of cost of sales and fuel, for certain midstream service contracts where we also purchase raw natural gas or unfractionated NGLs. Under Topic 606, these contracts are considered supplier contracts rather than contracts with customers. We have not completed our analysis to quantify the amount expected to be reclassified to cost of sales and fuel from services revenue, but expect it to be material. We do not believe the adoption of Topic 606 will have a material impact on operating income or net income. We are developing required disclosures and expect to disaggregate revenues on a segment basis similar to our current presentation in Management’s Discussion and Analysis. We expect our disclosure of unsatisfied performance obligations to relate primarily to firm transportation contracts. We do not expect a material contract asset balance and expect our contract liability balance to include storage contracts that have been prepaid by customers and contributions in aid of construction received from customers. ASU 2016-01, “Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities” The standard 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. First quarter 2018 We do not have any equity investments classified as available-for-sale or accounted for using the cost method, therefore, we do not expect adoption of this standard to have a material impact on us. ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments” The standard clarifies the classification of certain cash receipts and cash payments on the statement of cash flows where diversity in practice has been identified. First quarter 2018 We do not expect the adoption of this standard to materially impact us. ASU 2017-07, “Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost” The standard requires the service cost component of net benefit cost to be reported in the same line item or items as other compensation costs from services rendered by the pertinent employees during the period. The other components of net benefit cost are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations. First quarter 2018 We do not expect the adoption of this standard to materially impact us. Standard Description Date of Adoption Effect on the Financial Statements or Other Significant Matters Standards that are not yet adopted ( continued ) ASU 2016-02, “Leases (Topic 842)” The standard requires the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases under previous GAAP. It also requires qualitative disclosures along with specific quantitative disclosures by lessees and lessors to meet the objective of enabling users of financial statements to assess the amount, timing and uncertainty of cash flows arising from leases. First quarter 2019 We are evaluating our current leases and other contracts that may be considered leases under the new standard and the impact on our internal controls, accounting policies and financial statements and disclosures. ASU 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities The standard more closely aligns hedge accounting with companies’ existing risk-management strategies by expanding the strategies eligible for hedge accounting, relaxing the timing requirements of hedge documentation and effectiveness assessments, permitting in certain cases, the use of qualitative assessments on an ongoing basis to assess hedge effectiveness, and requiring new disclosures and presentation. First Quarter 2019 We are evaluating the timing of adoption and the impact of this standard on us. At adoption, we expect to record a cumulative-effect adjustment to the opening balance of retained earnings and other comprehensive income to eliminate the separate measurement of hedge ineffectiveness, which we do not expect to be material. We expect immaterial changes to disclosures as a result of adopting this standard. ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” The standard requires a financial asset (or a group of financial assets) measured at amortized cost basis to be presented net of the allowance for credit losses to reflect the net carrying value at the amount expected to be collected on the financial asset; and the initial allowance for credit losses for purchased financial assets, including available-for-sale debt securities, to be added to the purchase price rather than being reported as a credit loss expense. First quarter 2020 We do not expect the adoption of this standard to materially impact us. ASU 2017-04, “Intangibles- Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment” The standard simplifies the subsequent measurement of goodwill by eliminating the requirement to calculate the implied fair value of goodwill under step 2. Instead, an entity will recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. The standard does not change step zero or step 1 assessments. First quarter 2020 We do not expect the adoption of this standard to materially impact us. Goodwill Impairment Review - We assess our goodwill for impairment at least annually as of July 1. At July 1, 2017, we assessed qualitative factors to determine whether it was more likely than not that the fair value of each of our reporting units was less than its carrying amount. After assessing qualitative factors (including macroeconomic conditions, industry and market considerations, cost factors and overall financial performance), we determined that it was more likely than not that the fair value of each reporting unit was greater than its respective carrying value, that no further testing was necessary and that goodwill was not considered impaired. Impairment Charges - In the third quarter 2017, following a review of nonstrategic assets for potential divestiture, we recorded $16.0 million of noncash impairment charges related to certain nonstrategic gathering and processing assets located in North Dakota and $4.3 million of noncash impairment charges related to a nonstrategic equity investment located in Oklahoma.

ONEOK PARTNERS ACQUISITION (Not

ONEOK PARTNERS ACQUISITION (Notes)	9 Months Ended
	Sep. 30, 2017
Business Acquisition [Line Items]
Business Acquisition, Description of Acquired Entity	ACQUISITION OF ONEOK PARTNERS On June 30, 2017 , we completed the Merger Transaction at a fixed exchange ratio of 0.985 of a share of our common stock for each ONEOK Partners common unit that we did not already own. We issued 168.9 million shares of our common stock to third-party common unitholders of ONEOK Partners in exchange for all of the 171.5 million outstanding common units of ONEOK Partners that we previously did not own. No fractional shares were issued in the Merger Transaction, and ONEOK Partners common unitholders instead received cash in lieu of fractional shares. As a result of the completion of the Merger Transaction, common units of ONEOK Partners are no longer publicly traded. As we controlled ONEOK Partners and continue to control ONEOK Partners after the Merger Transaction, the change in our ownership interest was accounted for as an equity transaction, and no gain or loss was recognized in our Consolidated Statements of Income resulting from the Merger Transaction. The Merger Transaction was a taxable exchange to the ONEOK Partners unitholders resulting in a book/tax difference in the basis of the underlying assets acquired. We recorded a deferred tax asset of approximately $2.1 billion , computed as the net of the equity value exchanged of $8.8 billion and noncontrolling interests of $3.0 billion at a tax rate of 37 percent , based on a preliminary tax allocation of the transaction value. Final allocation is subject to completion of our valuation study. Prior to June 30, 2017, we and our subsidiaries owned all of the general partner interest, which included incentive distribution rights, and a portion of the limited partner interest, which together represented a 41.2 percent ownership interest in ONEOK Partners. The equity interests in ONEOK Partners (which are consolidated in our financial statements) that were owned by the public until June 30, 2017, are reflected in “Noncontrolling interests” in our accompanying Consolidated Balance Sheet as of December 31, 2016. The earnings of ONEOK Partners that are attributed to its units held by the public until June 30, 2017, are reported as “Net income attributable to noncontrolling interest” in our accompanying Consolidated Statements of Income. Our general partner incentive distribution rights effectively terminated at the closing of the Merger Transaction. Effective with the close of the Merger Transaction, we, ONEOK Partners and the Intermediate Partnership issued, to the extent not already in place, guarantees of the indebtedness of ONEOK and ONEOK Partners. Supplemental Cash Flow Information - Our noncash balance sheet activity related to the Merger Transaction is as follows (in millions): Common stock $ 1.7 Paid-in capital $ 5,228.6 Accumulated other comprehensive loss $ (40.3 ) Noncontrolling interests in consolidated subsidiaries $ (3,043.5 ) Deferred income taxes $ (2,146.5 )

FAIR VALUE MEASUREMENTS (Notes)

FAIR VALUE MEASUREMENTS (Notes)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Determining Fair Value - We define fair value as the price that would be received from the sale of an asset or the transfer of a liability in an orderly transaction between market participants at the measurement date. We use market and income approaches to determine the fair value of our assets and liabilities and consider the markets in which the transactions are executed. We measure the fair value of a group of financial assets and liabilities consistent with how a market participant would price the net risk exposure at the measurement date. While many of the contracts in our derivative 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 the LIBOR interest-rate swaps market. We also take into consideration the potential impact on market prices of liquidating positions in an orderly manner over a reasonable period of time under current market conditions. We consider current market data in evaluating counterparties’, as well as our own, nonperformance risk, net of collateral, by using specific and sector bond yields and monitoring the credit default swap markets. Although we use our best estimates to determine the fair value of the derivative contracts we have executed, the ultimate market prices realized could differ from our estimates, and the differences could be material. The fair value of our forward-starting interest-rate swaps are determined using financial models that incorporate the implied forward LIBOR yield curve for the same period as the future interest-rate swap settlements. Fair Value Hierarchy - At each balance sheet date, we utilize a fair value hierarchy to classify fair value amounts recognized or disclosed in our financial statements based on the observability of inputs used to estimate such fair value. The levels of the hierarchy are described below: • Level 1 - fair value measurements are based on unadjusted quoted prices for identical securities in active markets, including NYMEX-settled prices. These balances are comprised predominantly of exchange-traded derivative contracts for natural gas and crude oil. • Level 2 - fair value measurements are based on significant observable pricing inputs, such as NYMEX-settled prices for natural gas and crude oil, and financial models that utilize implied forward LIBOR yield curves for interest-rate swaps. • Level 3 - fair value measurements are based on inputs that may include one or more unobservable inputs, including internally developed natural gas basis and NGL price curves that incorporate observable and unobservable market data from broker quotes, third-party pricing services, market volatilities derived from the most recent NYMEX close spot prices and forward LIBOR curves, and adjustments for the credit risk of our counterparties. We corroborate the data on which our fair value estimates are based using our market knowledge of recent transactions, analysis of historical correlations and validation with independent broker quotes. These balances categorized as Level 3 are composed of derivatives for natural gas and NGLs. We do not believe that our Level 3 fair value estimates have a material impact on our results of operations, as the majority of our derivatives are accounted for as hedges for which ineffectiveness has not been material. Determining the appropriate classification of our fair value measurements within the fair value hierarchy requires management’s judgment regarding the degree to which market data is observable or corroborated by observable market data. We categorize derivatives for which fair value is determined using multiple inputs within a single level, based on the lowest level input that is significant to the fair value measurement in its entirety. Recurring Fair Value Measurements - The following tables set forth our recurring fair value measurements for the periods indicated: September 30, 2017 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net (b) ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 1,237 $ — $ 16,629 $ 17,866 $ (17,839 ) $ 27 Interest-rate contracts — 45,684 — 45,684 — 45,684 Total derivative assets $ 1,237 $ 45,684 $ 16,629 $ 63,550 $ (17,839 ) $ 45,711 Derivative liabilities Commodity contracts Financial contracts $ (4,415 ) $ — $ (39,052 ) $ (43,467 ) $ 43,268 $ (199 ) Physical contracts — — (4,083 ) (4,083 ) — (4,083 ) Total derivative liabilities $ (4,415 ) $ — $ (43,135 ) $ (47,550 ) $ 43,268 $ (4,282 ) (a) - Derivative assets and liabilities are presented in our Consolidated Balance Sheets on a net basis. We net derivative assets and liabilities when a legally enforceable master-netting arrangement exists between the counterparty to a derivative contract and us. At September 30, 2017 , we held no cash and posted $52.8 million of cash with various counterparties, including $25.4 million of cash collateral that is offsetting derivative net liability positions under master-netting arrangements in the table above. The remaining $27.4 million of cash collateral in excess of derivative net liability positions is included in other current assets in our Consolidated Balance Sheets. (b) - Included in other current assets, other assets, other current liabilities or other deferred credits in our Consolidated Balance Sheets. December 31, 2016 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net (b) ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 1,147 $ — $ 4,564 $ 5,711 $ (4,760 ) $ 951 Interest rate contracts — 47,457 — 47,457 — 47,457 Total derivative assets $ 1,147 $ 47,457 $ 4,564 $ 53,168 $ (4,760 ) $ 48,408 Derivative liabilities Commodity contracts Financial contracts $ (31,458 ) $ — $ (24,861 ) $ (56,319 ) $ 56,319 $ — Physical contracts — — (3,022 ) (3,022 ) — (3,022 ) Interest-rate contracts — (12,795 ) — (12,795 ) — (12,795 ) Total derivative liabilities $ (31,458 ) $ (12,795 ) $ (27,883 ) $ (72,136 ) $ 56,319 $ (15,817 ) (a) - Derivative assets and liabilities are presented in our Consolidated Balance Sheets on a net basis. We net derivative assets and liabilities when a legally enforceable master-netting arrangement exists between the counterparty to a derivative contract and us. At December 31, 2016 , we held no cash and posted $67.7 million of cash with various counterparties, including $51.6 million of cash collateral that is offsetting derivative net liability positions under master-netting arrangements in the table above. The remaining $16.1 million of cash collateral in excess of derivative net liability positions is included in other current assets in our Consolidated Balance Sheets. (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: Three Months Ended Nine Months Ended September 30, September 30, Derivative Assets (Liabilities) 2017 2016 2017 2016 ( Thousands of dollars ) Net assets (liabilities) at beginning of period $ 750 $ (14,021 ) $ (23,319 ) $ 7,331 Total realized/unrealized gains (losses): Included in earnings (a) (675 ) 920 (417 ) 492 Included in other comprehensive income (loss) (26,581 ) 3,038 (2,770 ) (17,886 ) Net assets (liabilities) at end of period $ (26,506 ) $ (10,063 ) $ (26,506 ) $ (10,063 ) (a) - Included in commodity sales revenues in our Consolidated Statements of Income. Realized/unrealized gains (losses) include the realization of our derivative contracts through maturity. During the three and nine months ended September 30, 2017 and 2016 , gains or losses included in earnings attributable to the change in unrealized gains or losses relating to assets and liabilities still held at the end of each reporting period were not material. We recognize transfers into and out of the levels in the fair value hierarc hy as of the end of each reporting period. During the three and nine months ended September 30, 2017 and 2016 , there were no tra ns fers between levels. Other Financial Instruments - The approximate fair value of cash and cash equivalents, accounts receivable, accounts payable and short-term borrowings is equal to book value due to the short-term nature of these items. Our cash and cash equivalents are composed 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 our consolidated long-term debt, including current maturities, was $9.3 billion and $8.8 billion at September 30, 2017 , and December 31, 2016 , respectively. The book value of our consolidated long-term debt, including current maturities, was $8.5 billion and $8.3 billion at September 30, 2017 , and December 31, 2016 , respectively. The estimated fair value of the aggregate of our and ONEOK Partners’ senior notes outstanding was determined using quoted market prices for similar issues with similar terms and maturities. The estimated fair value of our consolidated long-term debt is classified as Level 2.

RISK MANAGEMENT AND HEDGING ACT

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES (Notes)	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES	RISK-MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES Risk-Management Activities - We are sensitive to changes in natural gas, crude oil and NGL prices, principally as a result of contractual terms under which these commodities are purchased, processed and sold. We are also subject to the risk of interest-rate fluctuation in the normal course of business. We use physical-forward purchases and sales and financial derivatives to secure a certain price for a portion of our natural gas, condensate and NGL products; to reduce our exposure to commodity price and interest-rate fluctuations; and to achieve more predictable cash flows. We follow established policies and procedures to assess risk and approve, monitor and report our risk-management activities. We have not used these instruments for trading purposes. 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 reduce the near-term commodity price risk associated with a portion of the forecasted sales of these commodities: • Futures contracts - Standardized contracts to purchase or sell natural gas and crude oil for future delivery or settlement under the provisions of exchange regulations; • Forward contracts - Nonstandardized commitments between two parties to purchase or sell natural gas, crude oil or NGLs for future physical delivery. These contracts are typically nontransferable and can only be canceled with the consent of both parties; • Swaps - Exchange of one or more payments based on the value of one or more commodities. These instruments transfer the financial risk associated with a future change in value between the counterparties of the transaction, without also conveying ownership interest in the asset or liability; and • Options - Contractual agreements that give the holder the right, but not the obligation, to buy or sell a fixed quantity of a commodity at a fixed price within a specified period of time. Options may either be standardized and exchange-traded or customized and nonexchange-traded. We may also use other instruments including collars to mitigate commodity price risk. A collar is a combination of a purchased put option and a sold call option, which places a floor and a ceiling price for commodity sales being hedged. In our Natural Gas Gathering and Processing segment, we are exposed to commodity price risk as a result of retaining a portion of the commodity sales proceeds associated with our POP with fee contracts. Under certain POP with fee contracts, our fees and POP percentage may increase or decrease if production volumes, delivery pressures or commodity prices change relative to specified thresholds. We also are exposed to basis risk between the various production and market locations where we buy 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 may expose this segment 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 may use physical-forward sales or purchases to reduce the impact of price fluctuations related to natural gas. At September 30, 2017 , and December 31, 2016 , 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. In July 2017, we settled $400 million of our forward-starting interest-rate swaps upon the completion of our underwritten public offering of $1.2 billion senior unsecured notes and $500 million of our interest-rate swaps used to hedge our LIBOR-based interest payments. In September 2017, we entered into forward-starting interest-rate swaps with notional amounts totaling $500 million to hedge the variability of interest payments on a portion of our forecasted debt issuances that may result from changes in the benchmark interest rate before the debt is issued. At September 30, 2017 , and December 31, 2016 , we had forward-starting interest-rate swaps with notional amounts totaling $1.3 billion and $1.2 billion , respectively, to hedge the variability of interest payments on a portion of our forecasted debt issuances and interest-rate swaps with notional amounts totaling $500 million and $1 billion , respectively, to hedge the variability of our LIBOR-based interest payments. All of our interest-rate swaps are designated as cash flow hedges. Accounting Treatment - Our accounting treatment of derivative instruments is consistent with that disclosed in Note A of the Notes to Consolidated Financial Statements in our Annual Report. Fair Values of Derivative Instruments - See Note C for a discussion of the inputs associated with our fair value measurements. The following table sets forth the fair values of derivative instruments for the periods indicated: September 30, 2017 December 31, 2016 Location in our Consolidated Balance Sheets Assets (Liabilities) Assets (Liabilities) ( Thousands of dollars ) Derivatives designated as hedging instruments Commodity contracts Financial contracts Other current assets/other current liabilities $ 9,180 $ (33,500 ) $ 1,155 $ (49,938 ) Other assets/other deferred credits 2,098 (2,815 ) 210 (2,142 ) Physical contracts Other current liabilities — (3,600 ) — (3,022 ) Other deferred credits — (483 ) — — Interest-rate contracts Other current assets/other current liabilities 252 — — (12,795 ) Other assets 45,432 — 47,457 — Total derivatives designated as hedging instruments 56,962 (40,398 ) 48,822 (67,897 ) Derivatives not designated as hedging instruments Commodity contracts Financial contracts Other current assets/other current liabilities 5,862 (6,444 ) 4,346 (4,239 ) Other assets/other deferred credits 726 (708 ) — — Total derivatives not designated as hedging instruments 6,588 (7,152 ) 4,346 (4,239 ) Total derivatives $ 63,550 $ (47,550 ) $ 53,168 $ (72,136 ) Notional Quantities for Derivative Instruments - The following table sets forth the notional quantities for derivative instruments held for the periods indicated: September 30, 2017 December 31, 2016 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 — (27.6 ) — (38.4 ) - Natural gas ( Bcf ) Put options 9.0 — 49.5 — - Crude oil and NGLs ( MMBbl ) Futures, forwards and swaps 2.8 (10.3 ) — (3.6 ) Basis - Natural gas ( Bcf ) Futures and swaps — (27.6 ) — (38.4 ) Interest-rate contracts ( Millions of dollars ) Swaps $ 1,750.0 $ — $ 2,150.0 $ — Derivatives not designated as hedging instruments: Fixed price -Natural gas ( Bcf ) Futures and swaps 2.7 — 0.4 — - NGLs ( MMBbl ) Futures, forwards and swaps 1.2 (2.2 ) 0.5 (0.7 ) Basis - Natural gas ( Bcf ) Futures and swaps 2.7 — 0.4 — 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 September 30, 2017 , our Consolidated Balance Sheet reflected a net loss of $181.8 million in accumulated other comprehensive loss. The portion of accumulated other comprehensive loss attributable to our commodity derivative financial instruments is an unrealized loss of $19.9 million , net of tax, which is expected to be realized within the next three years as the forecasted transactions affect earnings. If commodity prices remain at current levels, we will realize approximately $19.1 million in net losses , net of tax, over the next 12 months and approximately $0.8 million in net losses , net of tax, thereafter. The amount deferred in accumulated other comprehensive loss attributable to our settled interest-rate swaps is a loss of $91.0 million , net of tax, which will be recognized over the life of the long-term, fixed-rate debt, including losses of $13.8 million , net of tax, that will be reclassified into earnings during the next 12 months as the hedged items affect earnings. The remaining amounts in accumulated other comprehensive loss are attributable primarily to forward-starting interest-rate swaps with future settlement dates, which are expected to be amortized to interest expense over the life of long-term, fixed-rate debt upon issuance of the debt. The following table sets forth the unrealized effect of cash flow hedges recognized in other comprehensive income (loss) for the periods indicated: Three Months Ended Nine Months Ended Derivatives in Cash Flow Hedging Relationships September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Commodity contracts $ (42,450 ) $ 7,580 $ (6,123 ) $ (39,396 ) Interest-rate contracts 9,613 958 (3,853 ) (59,217 ) Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion) $ (32,837 ) $ 8,538 $ (9,976 ) $ (98,613 ) The following table sets forth the effect of cash flow hedges in our Consolidated Statements of Income for the periods indicated: Derivatives in Cash Flow Hedging Relationships Location of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion) Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Commodity contracts Commodity sales revenues $ (15,913 ) $ 908 $ (38,028 ) $ 29,456 Interest-rate contracts Interest expense (4,820 ) (4,802 ) (15,321 ) (14,302 ) Total gain (loss) reclassified from accumulated other comprehensive loss into net income on derivatives (effective portion) $ (20,733 ) $ (3,894 ) $ (53,349 ) $ 15,154 Credit Risk - We monitor the creditworthiness of our counterparties and compliance with policies and limits established by our Risk Oversight and Strategy Committee. We maintain credit policies with regard to our counterparties that we believe minimize overall credit risk. These policies include an evaluation of potential counterparties’ financial condition (including credit ratings, bond yields and credit default swap rates), collateral requirements under certain circumstances and the use of standardized master-netting agreements that allow us to net the positive and negative exposures associated with a single counterparty. We have counterparties whose credit is not rated, and for those customers, we use internally developed credit ratings. From time to time, we may enter into financial derivative instruments that contain provisions that require us to maintain an investment-grade credit rating from S&P and/or Moody’s. If our credit ratings on our senior unsecured long-term debt were to decline below investment grade, the counterparties to the derivative instruments could request collateralization on derivative instruments in net liability positions. There were no financial derivative instruments with contingent features related to credit risk at September 30, 2017 . 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 September 30, 2017 , the net credit exposure from our derivative assets is with investment-grade companies in the financial services sector.

DEBT DEBT (Notes)

DEBT DEBT (Notes)	9 Months Ended
	Sep. 30, 2017
Debt Disclosure [Abstract]
Debt [Text Block]	DEBT The following table sets forth our consolidated debt for the periods indicated: September 30, December 31, ( Thousands of dollars ) ONEOK Senior unsecured obligations: Commercial paper outstanding, bearing a weighted-average interest rate of 1.93% (a) $ 932,250 $ — $700,000 at 4.25% due February 2022 547,397 547,397 $500,000 at 7.5% due September 2023 500,000 500,000 $500,000 at 4.0% due July 2027 500,000 — $100,000 at 6.5% due September 2028 — 87,126 $100,000 at 6.875% due September 2028 100,000 100,000 $400,000 at 6.0% due June 2035 400,000 400,000 $700,000 at 4.95% due July 2047 700,000 — ONEOK Partners Commercial paper outstanding (a) — 1,110,277 Senior unsecured obligations: $400,000 at 2.0% due October 2017 — 400,000 $425,000 at 3.2% due September 2018 425,000 425,000 $1,000,000 term loan, variable rate, due January 2019 500,000 1,000,000 $500,000 at 8.625% due March 2019 500,000 500,000 $300,000 at 3.8% due March 2020 300,000 300,000 $900,000 at 3.375 % due October 2022 900,000 900,000 $425,000 at 5.0 % due September 2023 425,000 425,000 $500,000 at 4.9 % due March 2025 500,000 500,000 $600,000 at 6.65% due October 2036 600,000 600,000 $600,000 at 6.85% due October 2037 600,000 600,000 $650,000 at 6.125% due February 2041 650,000 650,000 $400,000 at 6.2% due September 2043 400,000 400,000 Guardian Pipeline Weighted average 7.85% due December 2022 38,520 44,257 Total debt 9,518,167 9,489,057 Unamortized portion of terminated swaps 18,897 20,186 Unamortized debt issuance costs and discounts (80,164 ) (68,320 ) Current maturities of long-term debt (432,650 ) (410,650 ) Short-term borrowings (b) (932,250 ) (1,110,277 ) Long-term debt $ 8,092,000 $ 7,919,996 (a) - In July 2017, the commercial paper outstanding under the ONEOK Partners commercial paper program was repaid as it matured with a combination of proceeds from new issuances from ONEOK’s recently established $2.5 billion commercial paper program, cash on hand and proceeds from our July 2017 $1.2 billion senior notes issuance. The $2.4 billion ONEOK Partners commercial paper program was terminated in July 2017. (b) - Individual issuances of commercial paper under our commercial paper program generally mature in 90 days or less. These issuances are supported by and reduce the borrowing capacity under the 2017 Credit Agreement. 2017 Credit Agreement - In April 2017, we entered into the 2017 Credit Agreement with a syndicate of banks, which became effective June 30, 2017, with the close of the Merger Transaction and the terminations of the ONEOK Credit Agreement and ONEOK Partners Credit Agreement. The 2017 Credit Agreement is a $2.5 billion revolving credit facility and 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 2017 Credit Agreement, adjusted for all noncash charges and increased for projected EBITDA from certain lender-approved capital expansion projects) of no more than 5.75 to 1 at September 30, 2017, and for the following quarter; 5.5 to 1 for the subsequent two quarters; and 5.0 to 1 thereafter. Once the covenant decreases to 5.0 to 1, if we consummate one or more acquisitions in which the aggregate purchase 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 is completed and the two following quarters. The 2017 Credit Agreement includes a $100 million sublimit for the issuance of standby letters of credit and a $200 million sublimit for swingline loans. Under the terms of the 2017 Credit Agreement, we may request an increase in the size of the facility to an aggregate of $3.5 billion by either commitments from new lenders or increased commitments from existing lenders. The 2017 Credit Agreement contains provisions for an applicable margin rate and an annual facility fee, both of which adjust with changes in our credit ratings. Based on our current credit ratings, borrowings, if any, will accrue at LIBOR plus 110 basis points , and the annual facility fee is 15 basis points . We have the option to request two one-year extensions, subject to lender approval, which may be used for working capital, capital expenditures, acquisitions and mergers, the issuance of letters of credit and for other general corporate purposes. At September 30, 2017, our ratio of indebtedness to adjusted EBITDA was 4.9 to 1, and we were in compliance with all covenants under the 2017 Credit Agreement. Issuances - In July 2017, we completed an underwritten public offering of $1.2 billion senior unsecured notes consisting of $500 million , 4.0 percent senior notes due 2027, and $700 million , 4.95 percent senior notes due 2047. The net proceeds, after deducting underwriting discounts, commissions and offering expenses, were approximately $1.18 billion . The proceeds were used for general corporate purposes, which included repayment of existing indebtedness and capital expenditures. In January 2016, ONEOK Partners entered into the $1.0 billion senior unsecured Term Loan Agreement with a syndicate of banks. The Term Loan Agreement matures in January 2019 and bears interest at LIBOR plus 130 basis points based on our current credit ratings. At September 30, 2017, the interest rate was 2.54 percent . The Term Loan Agreement contains an option, which may be exercised up to two times, to extend the term of the loan, in each case, for an additional one-year term, subject to approval of the banks. The Term Loan Agreement allows prepayment of all or any portion outstanding without penalty or premium and contains substantially the same covenants as our 2017 Credit Agreement. During the first quarter 2016, ONEOK Partners drew the full $1.0 billion available under the agreement and used the proceeds to repay $650 million of senior notes at maturity, to repay amounts outstanding under its commercial paper program and for general partnership purposes. In April 2017, ONEOK Partners entered into the first amendment to the Term Loan Agreement, which, among other things, added ONEOK as a guarantor to the Term Loan Agreement effective June 30, 2017, with the close of the Merger Transaction described in Note B. Repayments - In September 2017, we repaid ONEOK Partners’ $400 million , 2.0 percent senior notes due in October 2017 with a combination of cash on hand and short-term borrowings. In July 2017, we redeemed our 6.5 percent senior notes due 2028 at a redemption price of approximately $87 million , including the outstanding principal amount, plus accrued and unpaid interest, with cash on hand. Also in July 2017, we repaid $500 million of the $1.0 billion Term Loan Agreement due 2019. Debt Guarantees - Effective June 30, 2017, with the Merger Transaction, we, ONEOK Partners and the Intermediate Partnership issued, to the extent not already in place, guarantees of the indebtedness of ONEOK and ONEOK Partners.

EQUITY (Notes)

EQUITY (Notes)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
EQUITY	EQUITY Ownership Interest in ONEOK Partners - At December 31, 2016, we and our subsidiaries owned all of the general partner interest, which included incentive distribution rights, and a portion of the limited partner interest, which together represented a 41.2 percent ownership interest in ONEOK Partners consisting of approximately 41.3 million common units and 73.0 million Class B units, which are convertible, at our option, into common units. The portion of ONEOK Partners that we did not own is reflected in our 2016 Consolidated Balance Sheet under the caption “Noncontrolling interests” along with the 20 percent of WTLPG that we do not own. On June 30, 2017, we completed the Merger Transaction at a fixed exchange ratio of 0.985 of a share of our common stock for each ONEOK Partners common unit that we did not already own. We issued 168.9 million shares of our common stock to third-party common unitholders of ONEOK Partners in exchange for all of the 171.5 million outstanding common units of ONEOK Partners that we previously did not own. At September 30, 2017, the caption “Noncontrolling interests” on our Consolidated Balance Sheet reflects only the 20 percent of WTLPG that we do not own. Cash Distributions - Prior to the consummation of the Merger Transaction, we received distributions from ONEOK Partners on our common and Class B units and our 2 percent general partner interest, which included our incentive distribution rights. Additional information about ONEOK Partners’ cash distributions and our incentive distribution rights for the periods prior to June 30, 2017, is included under “Cash Distributions” in Note O of the Notes to Consolidated Financial Statements in our Annual Report. Distributions paid to ONEOK Partners unitholders of record at the close of business on January 30, 2017 , and May 1, 2017 , were $0.79 per unit. As a result of the Merger Transaction, we are entitled to receive all available ONEOK Partners cash. Our incentive distribution rights effectively terminated at the close of the Merger Transaction. The following table sets forth ONEOK Partners’ distributions declared and paid during the periods prior to the closing of the Merger Transaction on June 30, 2017: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 ( Thousands, except per unit amounts ) Distribution per unit $ — $ 0.79 $ 1.58 $ 2.37 General partner distributions $ — $ 6,660 $ 13,320 $ 19,980 Incentive distributions — 100,538 201,076 301,614 Distributions to general partner — 107,198 214,396 321,594 Limited partner distributions to ONEOK — 90,323 180,646 270,969 Limited partner distributions to other unitholders — 135,480 270,959 406,439 Total distributions paid $ — $ 333,001 $ 666,001 $ 999,002 Dividends - Holders of our common stock share equally in any dividend declared by our board of directors, subject to the rights of the holders of outstanding preferred stock. Dividends paid on our common stock to shareholders of record at the close of business on January 30, 2017, May 1, 2017, and August 7, 2017, were $0.615 , $0.615 , and $0.745 per share, respectively. A dividend of $0.745 per share was declared for shareholders of record at the close of business on November 6, 2017 , payable November 14, 2017 . In April 2017, through a wholly owned subsidiary, we contributed 20,000 shares of newly issued Series E Preferred Stock, having an aggregate value of $20 million , to the Foundation for use in charitable and nonprofit causes. The contribution was recorded as a $20 million noncash expense in the second quarter 2017 and is included in other expense in our Consolidated Statements of Income. The Series E Preferred Stock pays quarterly dividends on each share of Series E Preferred Stock, when, as and if declared by our Board of Directors, at a rate of 5.5 percent per year. In August 2017, we paid dividends of $0.4 million for the Series E Preferred Stock. Dividends totaling approximately $0.3 million were declared for the Series E Preferred Stock and are payable November 14, 2017 . The $20 million issuance of the shares of Series E Preferred Stock and the related accrued dividends of approximately $0.1 million at September 30, 2017, represent noncash financing activities. Equity Issuances - In July 2017, we established an “at-the-market” equity program for the offer and sale from time to time of our common stock up to an aggregate amount of $1 billion . The program allows us to offer and sell our common stock at prices we deem appropriate through a sales agent. Sales of our common stock may be 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 stock under the program. During the three months ended September 30, 2017, we sold 1.2 million shares of common stock through our “at-the-market” equity program that resulted in net proceeds of $64.7 million , of which $30.8 million had settled as of September 30, 2017. In October 2017, we sold an additional 2.1 million shares of common stock through this program that resulted in net proceeds of $119.5 million . The net proceeds from these issuances were used for general corporate purposes, including repayment of outstanding indebtedness and to fund capital expenditures. Prior to the close of the Merger Transaction, ONEOK Partners had an “at-the-market” equity program for the offer and sale from time to time of its common units, up to an aggregate amount of $650 million . During the six months ended June 30, 2017, and the year ended December 31, 2016, no common units were sold through ONEOK Partners’ “at-the-market” equity program. Upon the close of the Merger Transaction on June 30, 2017, the ONEOK Partners “at-the-market” equity program terminated.

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ACCUMULATED OTHER COMPREHENSIVE INCOME (Notes)	9 Months Ended
	Sep. 30, 2017
ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS)	ACCUMULATED OTHER COMPREHENSIVE LOSS The following table sets forth the balance in accumulated other comprehensive loss for the period indicated: Unrealized Gains (Losses) on Risk- Management Assets/Liabilities (a) Pension and Postretirement Benefit Plan Obligations (a) (b) Unrealized Gains (Losses) on Risk- Management Assets/Liabilities of Unconsolidated Affiliates (a) Accumulated Other Comprehensive Loss (a) ( Thousands of dollars ) January 1, 2017 $ (52,155 ) $ (101,236 ) $ (959 ) $ (154,350 ) Other comprehensive income (loss) before reclassifications (14,892 ) 8 (588 ) (15,472 ) Amounts reclassified from accumulated other comprehensive loss 22,126 6,114 99 28,339 Impact of Merger Transaction (Note B) (c) (40,288 ) — — (40,288 ) Net current-period other comprehensive income (loss) attributable to ONEOK (33,054 ) 6,122 (489 ) (27,421 ) September 30, 2017 $ (85,209 ) $ (95,114 ) $ (1,448 ) $ (181,771 ) (a) - All amounts are presented net of tax. (b) - Includes amounts related to supplemental executive retirement plan. (c) - Includes the remaining portion of ONEOK Partners’ accumulated other comprehensive loss at June 30, 2017, that we acquired in the Merger Transaction, related to commodity and interest-rate contracts. The following table sets forth the effect of reclassifications from accumulated other comprehensive loss in our Consolidated Statements of Income for the periods indicated: Details about Accumulated Other Components Three Months Ended Nine Months Ended Affected Line Item in the Statements of Income September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Unrealized gains (losses) on risk-management assets/liabilities Commodity contracts $ (15,913 ) $ 908 $ (38,028 ) $ 29,456 Commodity sales revenues Interest-rate contracts (4,820 ) (4,802 ) (15,321 ) (14,302 ) Interest expense (20,733 ) (3,894 ) (53,349 ) 15,154 Income before income taxes 7,671 811 13,077 (1,658 ) Income tax expense (13,062 ) (3,083 ) (40,272 ) 13,496 Net income Noncontrolling interests — (1,774 ) (18,146 ) 10,459 Less: Net income attributable to noncontrolling interests $ (13,062 ) $ (1,309 ) $ (22,126 ) $ 3,037 Net income attributable to ONEOK Pension and postretirement benefit plan obligations (a) Amortization of net loss $ (3,811 ) $ (2,999 ) $ (11,435 ) $ (8,994 ) Amortization of unrecognized prior service cost 415 416 1,245 1,246 (3,396 ) (2,583 ) (10,190 ) (7,748 ) Income before income taxes 1,358 1,033 4,076 3,099 Income tax expense $ (2,038 ) $ (1,550 ) $ (6,114 ) $ (4,649 ) Net income attributable to ONEOK Unrealized gains (losses) on risk-management assets/liabilities of unconsolidated affiliates $ (83 ) $ — $ (264 ) $ — Equity in net earnings from investments 31 — 59 — Income tax expense (52 ) — (205 ) — Net income Noncontrolling interests — — (106 ) — Less: Net income attributable to noncontrolling interests $ (52 ) $ — $ (99 ) $ — Net income attributable to ONEOK Total reclassifications for the period attributable to ONEOK $ (15,152 ) $ (2,859 ) $ (28,339 ) $ (1,612 ) Net income attributable to ONEOK (a) - These components of accumulated other comprehensive loss are included in the computation of net periodic benefit cost. See Note I for additional detail of our net periodic benefit cost.

EARNINGS PER SHARE EARNINGS PER

EARNINGS PER SHARE EARNINGS PER SHARE (Notes)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	EARNINGS PER SHARE The following tables set forth the computation of basic and diluted EPS from continuing operations for the periods indicated: Three Months Ended September 30, 2017 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS from continuing operations Income from continuing operations attributable to ONEOK available for common stock $ 165,466 380,907 $ 0.43 Diluted EPS from continuing operations Effect of dilutive securities — 2,512 Income from continuing operations attributable to ONEOK available for common stock and common stock equivalents $ 165,466 383,419 $ 0.43 Three Months Ended September 30, 2016 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS from continuing operations Income from continuing operations attributable to ONEOK available for common stock $ 92,720 211,309 $ 0.44 Diluted EPS from continuing operations Effect of dilutive securities — 1,561 Income from continuing operations attributable to ONEOK available for common stock and common stock equivalents $ 92,720 212,870 $ 0.44 Nine Months Ended September 30, 2017 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS from continuing operations Income from continuing operations attributable to ONEOK available for common stock $ 324,303 268,108 $ 1.21 Diluted EPS from continuing operations Effect of dilutive securities — 2,241 Income from continuing operations attributable to ONEOK available for common stock and common stock equivalents $ 324,303 270,349 $ 1.20 Nine Months Ended September 30, 2016 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS from continuing operations Income from continuing operations attributable to ONEOK available for common stock $ 263,289 211,038 $ 1.25 Diluted EPS from continuing operations Effect of dilutive securities — 1,085 Income from continuing operations attributable to ONEOK available for common stock and common stock equivalents $ 263,289 212,123 $ 1.24

EMPLOYEE BENEFIT PLANS EMPLOYEE

EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS (Notes)	9 Months Ended
	Sep. 30, 2017
Defined Benefit Plan [Abstract]
EMPLOYEE BENEFIT PLANS	EMPLOYEE BENEFIT PLANS The following tables set forth the components of net periodic benefit cost for our pension and postretirement benefit plans for our continuing operations for the periods indicated: Pension Benefits Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Components of net periodic benefit cost Service cost $ 1,721 $ 1,622 $ 5,165 $ 4,866 Interest cost 4,655 4,946 13,965 14,840 Expected return on plan assets (5,336 ) (5,077 ) (16,008 ) (15,231 ) Amortization of net loss 3,392 2,737 10,176 8,210 Net periodic benefit cost $ 4,432 $ 4,228 $ 13,298 $ 12,685 Postretirement Benefits Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Components of net periodic benefit cost Service cost $ 165 $ 149 $ 495 $ 447 Interest cost 565 601 1,695 1,803 Expected return on plan assets (564 ) (531 ) (1,692 ) (1,593 ) Amortization of prior service credit (415 ) (416 ) (1,245 ) (1,246 ) Amortization of net loss 419 262 1,259 784 Net periodic benefit cost $ 170 $ 65 $ 512 $ 195

UNCONSOLIDATED AFFILIATES (Note

UNCONSOLIDATED AFFILIATES (Notes)	9 Months Ended
	Sep. 30, 2017
Equity Method Investments and Joint Ventures [Abstract]
UNCONSOLIDATED AFFILIATES	UNCONSOLIDATED AFFILIATES Equity in Net Earnings from Investments - The following table sets forth our equity in net earnings from investments for the periods indicated: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Northern Border Pipeline $ 16,440 $ 17,854 $ 50,879 $ 52,251 Overland Pass Pipeline Company 15,793 13,886 44,243 40,798 Other 7,825 3,415 23,863 7,392 Equity in net earnings from investments $ 40,058 $ 35,155 $ 118,985 $ 100,441 Impairment of equity investments $ (4,270 ) $ — $ (4,270 ) $ — Unconsolidated Affiliates Financial Information - The following table sets forth summarized combined financial information of our unconsolidated affiliates for the periods indicated: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Income Statement Operating revenues $ 163,627 $ 143,967 $ 475,510 $ 423,170 Operating expenses $ 69,740 $ 66,490 $ 206,141 $ 191,863 Net income $ 87,330 $ 72,672 $ 260,533 $ 214,129 Distributions paid to us $ 49,414 $ 40,822 $ 146,094 $ 149,399 We incurred expenses in transactions with unconsolidated affiliates of $39.9 million and $36.4 million for the three months ended September 30, 2017 and 2016 , respectively, and $116.0 million and $105.3 million for the nine months ended September 30, 2017 and 2016 , respectively, primarily related to Overland Pass Pipeline Company and Northern Border Pipeline. Accounts payable to our equity-method investees at September 30, 2017 , and December 31, 2016 , were $13.1 million and $11.1 million , respectively. Northern Border Pipeline - The Northern Border Pipeline partnership agreement provides that distributions to Northern Border Pipeline’s partners are to be made on a pro rata basis according to each partner’s percentage interest. The Northern Border Pipeline Management Committee determines the amount and timing of such distributions. Any changes to, or suspension of, the cash distribution policy of Northern Border Pipeline requires the unanimous approval of the Northern Border Pipeline Management Committee. Cash distributions are equal to 100 percent of distributable cash flow as determined from Northern Border Pipeline’s financial statements based upon EBITDA less interest expense and maintenance capital expenditures. Loans or other advances from Northern Border Pipeline to its partners or affiliates are prohibited under its credit agreement. During the nine months ended September 30, 2017 , we made an equity contribution of $83 million to Northern Border Pipeline. 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, cash distributions from Overland Pass Pipeline Company requires the unanimous approval of the Overland Pass Pipeline Company Management Committee. Cash distributions are equal to 100 percent of available cash as defined in the limited liability company agreement. Roadrunner Gas Transmission - The Roadrunner limited liability company agreement provides that distributions to members are made on a pro rata basis according to each member’s ownership interest. As the operator, we have been delegated the authority to determine such distributions in accordance with, and on the frequency set forth in, the Roadrunner limited liability company agreement. Cash distributions are equal to 100 percent of available cash, as defined in the limited liability company agreement. We have an operating agreement with Roadrunner that provides for reimbursement or payment to us for management services and certain operating costs. Reimbursements and payments from Roadrunner included in operating income in our Consolidated Statements of Income for the three and nine months ended September 30, 2017 and 2016 , were not material.

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Notes)	9 Months Ended
	Sep. 30, 2017
Commitments and Contingencies Disclosure [Abstract]
COMMITMENTS AND CONTINGENCIES	COMMITMENTS AND CONTINGENCIES Environmental Matters and Pipeline Safety - The operation of pipelines, plants and other facilities for the gathering, processing, transportation and storage of natural gas, NGLs, condensate and other products is subject to numerous and complex laws and regulations pertaining to health, safety and the environment. As an owner and/or operator of these facilities, we must comply with United States laws and regulations at the federal, state and local levels that relate to air and water quality, hazardous and solid waste management and disposal, and other environmental matters. The cost of planning, designing, constructing and operating pipelines, plants and other facilities must incorporate compliance with environmental laws and regulations and safety standards. Failure to comply with these laws and regulations may trigger a variety of administrative, civil and potentially criminal enforcement measures, including citizen suits, which can include the assessment of monetary penalties, the imposition of remedial requirements and the issuance of injunctions or restrictions on operation. Management believes that, based on currently known information, compliance with these laws and regulations will not have a material adverse effect on our results of operations, financial condition or cash flows. Legal Proceedings - Gas Index Pricing Litigation - As was previously reported, the United States District Court for the District of Nevada (the Court) granted summary judgment in March 2017 to our affiliate ONEOK Energy Services Company, L.P. (OESC) in Sinclair Oil Corporation v. ONEOK Energy Services Company, L.P. (filed in the United States District Court for the District of Wyoming in September 2005, transferred to MDL-1566 in the Court) after determining that the plaintiff’s claim was barred by a release obtained in a prior lawsuit against us and OESC. In September 2017, the Court entered a final judgment in favor of OESC in Sinclair . Later that month, Sinclair Oil Corporation filed a notice of appeal of this decision to the Ninth Circuit Court of Appeals. We expect that future charges, if any, from the ultimate resolution of the Sinclair case will not be material to our results of operations, financial position or cash flows. As was previously reported, the Court gave final approval in May 2017 to the previously announced settlements of Learjet, Inc., et al. v. ONEOK, Inc., et al. (filed in the District Court of Wyandotte, Kansas, in November 2005, transferred to MDL-1566 in the Court); Arandell Corporation, et al. v. Xcel Energy, Inc., et al. (filed in the Circuit Court for Dane County, Wisconsin, in December 2006, transferred to MDL-1566 in the Court); Heartland Regional Medical Center, et al. v. ONEOK, Inc., et al. (filed in the Circuit Court of Buchanan County, Missouri, in March 2007, transferred to MDL-1566 in the Court); and NewPage Wisconsin System v. CMS Energy Resource Management Company, et al. (filed in the Circuit Court for Wood County, Wisconsin, in March 2009, transferred to MDL-1566 in the Court and now consolidated with the Arandell case). Thereafter, the Court entered a final judgment dismissing these actions with prejudice as to us and our affiliates, which became final and nonappealable in July 2017. The amount paid to settle these cases was not material to our results of operations, financial position or cash flows and was paid with cash on hand. ONEOK Partners Class Action Litigation - As was previously reported, ONEOK Partners settled two putative class action lawsuits captioned Juergen Krueger, Individually And On Behalf Of All Others Similarly Situated v. ONEOK Partners, L.P., et al. (filed in the United States District Court for the Northern District of Oklahoma) and Max Federman, On Behalf of Himself and All Others Similarly Situated v. ONEOK Partners, L.P., et al. (filed in the United States District Court for the Northern District of Oklahoma) by agreeing to make certain disclosures in a filing with the SEC about the Merger Transaction in addition to those made in the final proxy statement filed with the SEC. The Krueger and Federman actions were dismissed on June 14, 2017, as moot, with prejudice as to the named plaintiffs and without prejudice as to any other members of a putative class. In July 2017, ONEOK Partners entered into a settlement concerning attorney’s fees and expenses for plaintiffs’ counsel that was not material to our results of operations, financial position or cash flows and was paid with cash on hand. Other Legal Proceedings - We are a party to various other litigation matters and claims that have arisen in the normal course of our operations. While the results of these 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 (Notes)

SEGMENTS (Notes)	9 Months Ended
	Sep. 30, 2017
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
SEGMENTS	SEGMENTS Segment Descriptions - Our operations are divided into three reportable business segments, as follows: • our Natural Gas Gathering and Processing segment gathers, treats and processes natural gas; • our Natural Gas Liquids segment gathers, treats, fractionates and transports NGLs and stores, markets and distributes NGL products; and • our Natural Gas Pipelines segment operates regulated interstate and intrastate natural gas transmission pipelines and natural gas storage facilities. Other and eliminations consist of corporate and Merger Transaction-related costs, the operating and leasing activities of our headquarters building and related parking facility and eliminations necessary to reconcile our reportable segments to our Consolidated Financial Statements. Accounting Policies - The accounting policies of the segments are described in Note A of the Notes to Consolidated Financial Statements in our Annual Report. Our chief operating decision-maker reviews the financial performance of each of our three segments, as well as our financial performance as a whole, on a regular basis. Adjusted EBITDA by segment is utilized in this evaluation. We believe this financial measure is useful to investors because it and similar measures are used by many companies in our industry as a measurement of financial performance and are commonly employed by financial analysts and others to evaluate our financial performance and to compare financial performance among companies in our industry. Adjusted EBITDA for each segment is defined as net income adjusted for interest expense, depreciation and amortization, noncash impairment charges, income taxes, allowance for equity funds used during construction, noncash compensation and other noncash items. This calculation may not be comparable with similarly titled measures of other companies. Customers - The primary customers of our Natural Gas Gathering and Processing segment are crude oil and natural gas producers, which include both large integrated and independent exploration and production companies. Our Natural Gas Liquids segment’s customers are primarily NGL and natural gas gathering and processing companies; large integrated and independent crude oil and natural gas production companies; propane distributors; ethanol producers; and petrochemical, refining and NGL marketing companies. Our Natural Gas Pipelines segment’s customers are primarily local natural gas distribution companies, electric-generation companies, large industrial companies, municipalities, irrigation customers and marketing companies. For the three and nine months ended September 30, 2017 and 2016 , we had no single customer from which we received 10 percent or more of our consolidated revenues. Operating Segment Information - The following tables set forth certain selected financial information for our operating segments for the periods indicated: Three Months Ended Natural Gas Natural Gas Natural Gas Total ( Thousands of dollars ) Sales to unaffiliated customers $ 453,432 $ 2,348,052 $ 104,340 $ 2,905,824 Intersegment revenues 329,496 153,927 2,098 485,521 Total revenues 782,928 2,501,979 106,438 3,391,345 Cost of sales and fuel (exclusive of depreciation and items shown separately below) (566,988 ) (2,136,207 ) (10,614 ) (2,713,809 ) Operating costs (80,197 ) (90,234 ) (29,838 ) (200,269 ) Equity in net earnings from investments 3,433 15,287 21,338 40,058 Other 2,774 3,094 203 6,071 Segment adjusted EBITDA $ 141,950 $ 293,919 $ 87,527 $ 523,396 Depreciation and amortization $ (46,842 ) $ (41,929 ) $ (12,765 ) $ (101,536 ) Impairment of long-lived assets and equity investments $ (20,240 ) $ — $ — $ (20,240 ) Capital expenditures $ 85,542 $ 27,024 $ 18,811 $ 131,377 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $293.1 million , of which $250.2 million related to sales within the segment and cost of sales and fuel of $124.2 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $65.6 million and cost of sales and fuel of $10.5 million . Three Months Ended September 30, 2017 Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated Sales to unaffiliated customers $ 2,905,824 $ 542 $ 2,906,366 Intersegment revenues 485,521 (485,521 ) — Total revenues $ 3,391,345 $ (484,979 ) $ 2,906,366 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (2,713,809 ) $ 484,393 $ (2,229,416 ) Operating costs $ (200,269 ) $ (6,781 ) $ (207,050 ) Depreciation and amortization $ (101,536 ) $ (762 ) $ (102,298 ) Impairment of long-lived assets and equity investments $ (20,240 ) $ — $ (20,240 ) Equity in net earnings from investments $ 40,058 $ — $ 40,058 Capital expenditures $ 131,377 $ 3,822 $ 135,199 Three Months Ended Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Total ( Thousands of dollars ) Sales to unaffiliated customers $ 361,717 $ 1,905,273 $ 90,401 $ 2,357,391 Intersegment revenues 150,501 133,984 1,676 286,161 Total revenues 512,218 2,039,257 92,077 2,643,552 Cost of sales and fuel (exclusive of depreciation and items shown separately below) (336,456 ) (1,694,161 ) (6,870 ) (2,037,487 ) Operating costs (69,443 ) (79,771 ) (28,373 ) (177,587 ) Equity in net earnings from investments 2,596 13,960 18,599 35,155 Other 922 (29 ) 4,871 5,764 Segment adjusted EBITDA $ 109,837 $ 279,256 $ 80,304 $ 469,397 Depreciation and amortization $ (44,994 ) $ (40,751 ) $ (12,057 ) $ (97,802 ) Capital expenditures $ 99,649 $ 30,533 $ 24,495 $ 154,677 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $299.2 million , of which $253.4 million related to sales within the segment and cost of sales and fuel of $119.6 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $61.0 million and cost of sales and fuel of $7.8 million . Three Months Ended September 30, 2016 Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated Sales to unaffiliated customers $ 2,357,391 $ 516 $ 2,357,907 Intersegment revenues 286,161 (286,161 ) — Total revenues $ 2,643,552 $ (285,645 ) $ 2,357,907 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (2,037,487 ) $ 285,894 $ (1,751,593 ) Operating costs $ (177,587 ) $ (6,564 ) $ (184,151 ) Depreciation and amortization $ (97,802 ) $ (748 ) $ (98,550 ) Equity in net earnings from investments $ 35,155 $ — $ 35,155 Capital expenditures $ 154,677 $ 3,597 $ 158,274 Nine Months Ended Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Total ( Thousands of dollars ) Sales to unaffiliated customers $ 1,286,669 $ 6,788,451 $ 305,019 $ 8,380,139 Intersegment revenues 843,350 455,197 6,086 1,304,633 Total revenues 2,130,019 7,243,648 311,105 9,684,772 Cost of sales and fuel (exclusive of depreciation and items shown separately below) (1,544,263 ) (6,188,501 ) (33,990 ) (7,766,754 ) Operating costs (225,079 ) (256,262 ) (92,468 ) (573,809 ) Equity in net earnings from investments 9,843 44,071 65,071 118,985 Other 3,658 2,501 1,427 7,586 Segment adjusted EBITDA $ 374,178 $ 845,457 $ 251,145 $ 1,470,780 Depreciation and amortization $ (137,843 ) $ (124,471 ) $ (37,906 ) $ (300,220 ) Impairment of long-lived assets and equity investments $ (20,240 ) $ — $ — $ (20,240 ) Total assets $ 5,385,778 $ 8,515,535 $ 2,040,445 $ 15,941,758 Capital expenditures $ 185,713 $ 59,813 $ 70,671 $ 316,197 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $878.8 million , of which $752.5 million related to sales within the segment and cost of sales and fuel of $359.6 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $197.3 million and cost of sales and fuel of $32.9 million . Nine Months Ended September 30, 2017 Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated Sales to unaffiliated customers $ 8,380,139 $ 1,610 $ 8,381,749 Intersegment revenues 1,304,633 (1,304,633 ) — Total revenues $ 9,684,772 $ (1,303,023 ) $ 8,381,749 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (7,766,754 ) $ 1,302,473 $ (6,464,281 ) Operating costs $ (573,809 ) $ (42,968 ) $ (616,777 ) Depreciation and amortization $ (300,220 ) $ (2,346 ) $ (302,566 ) Impairment of long-lived assets and equity investments $ (20,240 ) $ — $ (20,240 ) Equity in net earnings from investments $ 118,985 $ — $ 118,985 Total assets $ 15,941,758 $ 823,083 $ 16,764,841 Capital expenditures $ 316,197 $ 14,234 $ 330,431 Nine Months Ended Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Total ( Thousands of dollars ) Sales to unaffiliated customers $ 971,834 $ 5,030,820 $ 262,276 $ 6,264,930 Intersegment revenues 449,154 367,820 3,843 820,817 Total revenues 1,420,988 5,398,640 266,119 7,085,747 Cost of sales and fuel (exclusive of depreciation and items shown separately below) (902,747 ) (4,376,345 ) (15,914 ) (5,295,006 ) Operating costs (208,353 ) (236,722 ) (85,075 ) (530,150 ) Equity in net earnings from investments 7,987 41,211 51,243 100,441 Other 2,295 (748 ) 6,812 8,359 Segment adjusted EBITDA $ 320,170 $ 826,036 $ 223,185 $ 1,369,391 Depreciation and amortization $ (133,258 ) $ (122,153 ) $ (34,634 ) $ (290,045 ) Total assets $ 5,268,161 $ 8,257,203 $ 1,912,951 $ 15,438,315 Capital expenditures $ 325,820 $ 85,519 $ 71,721 $ 483,060 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $878.5 million , of which $742.6 million related to sales within the segment and cost of sales and fuel of $339.1 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $172.4 million and cost of sales and fuel of $19.1 million . Nine Months Ended September 30, 2016 Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated Sales to unaffiliated customers $ 6,264,930 $ 1,543 $ 6,266,473 Intersegment revenues 820,817 (820,817 ) — Total revenues $ 7,085,747 $ (819,274 ) $ 6,266,473 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (5,295,006 ) $ 820,352 $ (4,474,654 ) Operating costs $ (530,150 ) $ (22,855 ) $ (553,005 ) Depreciation and amortization $ (290,045 ) $ (2,230 ) $ (292,275 ) Equity in net earnings from investments $ 100,441 $ — $ 100,441 Total assets $ 15,438,315 $ 543,720 $ 15,982,035 Capital expenditures $ 483,060 $ 8,468 $ 491,528 Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Reconciliation of income from continuing operations to total segment adjusted EBITDA ( Thousands of dollars ) Income from continuing operations $ 166,531 $ 194,792 $ 528,707 $ 550,789 Add: Interest expense, net of capitalized interest 126,533 118,240 361,468 355,463 Depreciation and amortization 102,298 98,550 302,566 292,275 Income taxes 97,128 55,012 195,913 157,536 Impairment charges 20,240 — 20,240 — Noncash compensation expense 4,883 3,165 9,790 20,170 Other corporate costs and noncash items (a) 5,783 (362 ) 52,096 (6,842 ) Total segment adjusted EBITDA $ 523,396 $ 469,397 $ 1,470,780 $ 1,369,391 (a) - The nine months ended September 30, 2017, includes our April 2017 $20 million contribution of Series E Preferred Stock to the Foundation and costs related to the Merger Transaction of $29.5 million .

SUPPLEMENTAL CONDENSED CONSOLID

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION (Notes)	9 Months Ended
	Sep. 30, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Supplemental Condensed Consolidating Financial Information	SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION ONEOK and ONEOK Partners are issuers of certain public debt securities. Effective with the Merger Transaction, we, ONEOK Partners and the Intermediate Partnership issued, to the extent not already in place, guarantees of the indebtedness of ONEOK and ONEOK Partners. The Intermediate Partnership holds all of ONEOK Partners’ partnership interests and equity in its subsidiaries, as well as a 50 percent interest in Northern Border Pipeline. In lieu of providing separate financial statements for each subsidiary issuer and guarantor, we have included the accompanying condensed consolidating financial statements based on Rule 3-10 of the SEC’s Regulation S-X. We have presented each of the parent and subsidiary issuers in separate columns in this single set of condensed consolidating financial statements. For purposes of the following footnote: • we are referred to as “Parent Issuer and Guarantor”; • ONEOK Partners is referred to as “Subsidiary Issuer and Guarantor”; • the Intermediate Partnership is referred to as “Guarantor Subsidiary”; and • the “Non-Guarantor Subsidiaries” are all subsidiaries other than the Guarantor Subsidiary and Subsidiary Issuer and Guarantor. The following unaudited supplemental condensed consolidating financial information is presented on an equity-method basis reflecting the separate accounts of ONEOK, ONEOK Partners and the Intermediate Partnership, the combined accounts of the Non-Guarantor Subsidiaries, the combined consolidating adjustments and eliminations, and our consolidated amounts for the periods indicated. Condensed Consolidating Statements of Income Three Months Ended September 30, 2017 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 2,322.5 $ — $ 2,322.5 Services — — — 584.3 (0.5 ) 583.8 Total revenues — — — 2,906.8 (0.5 ) 2,906.3 Cost of sales and fuel (exclusive of items shown separately below) — — — 2,229.4 — 2,229.4 Operating expenses 3.9 — 2.6 303.3 (0.5 ) 309.3 Impairment of long-lived assets — — — 16.0 — 16.0 Gain on sale of assets — — — (0.3 ) — (0.3 ) Operating income (3.9 ) — (2.6 ) 358.4 — 351.9 Equity in net earnings from investments 298.0 298.3 300.9 27.6 (884.7 ) 40.1 Impairment of equity investments — — — (4.3 ) — (4.3 ) Other income (expense), net 6.8 86.1 86.1 (4.3 ) (172.2 ) 2.5 Interest expense, net (43.2 ) (86.1 ) (86.1 ) (83.3 ) 172.2 (126.5 ) Income before income taxes 257.7 298.3 298.3 294.1 (884.7 ) — 263.7 Income taxes (91.9 ) — — (5.3 ) — (97.2 ) Net income 165.8 298.3 298.3 288.8 (884.7 ) 166.5 Less: Net income attributable to noncontrolling interests 0.1 — — 0.7 — 0.8 Net income attributable to ONEOK 165.7 298.3 298.3 288.1 (884.7 ) 165.7 Less: Preferred stock dividends 0.2 — — — — 0.2 Net income available to common shareholders $ 165.5 $ 298.3 $ 298.3 $ 288.1 $ (884.7 ) $ 165.5 Three Months Ended September 30, 2016 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 1,840.5 $ — $ 1,840.5 Services — — — 517.9 (0.5 ) 517.4 Total revenues — — — 2,358.4 (0.5 ) 2,357.9 Cost of sales and fuel (exclusive of items shown separately below) — — — 1,751.6 — 1,751.6 Operating expenses 6.7 — — 276.4 (0.5 ) 282.6 Gain on sale of assets — — — (5.7 ) — (5.7 ) Operating income (6.7 ) — — 336.1 — 329.4 Equity in net earnings from investments 273.5 274.3 274.3 17.4 (804.3 ) 35.2 Other income (expense), net 3.4 95.3 95.3 — (190.6 ) 3.4 Interest expense, net (25.7 ) (95.3 ) (95.3 ) (92.5 ) 190.6 (118.2 ) Income before income taxes 244.5 274.3 274.3 261.0 (804.3 ) 249.8 Income taxes (51.4 ) — — (3.6 ) — (55.0 ) Income from continuing operations 193.1 274.3 274.3 257.4 (804.3 ) 194.8 Income (loss) from discontinued operations, net of tax — — — (0.6 ) — (0.6 ) Net income 193.1 274.3 274.3 256.8 (804.3 ) 194.2 Less: Net income attributable to noncontrolling interests 101.0 — — 1.1 — 102.1 Net income attributable to ONEOK $ 92.1 $ 274.3 $ 274.3 $ 255.7 $ (804.3 ) $ 92.1 Nine Months Ended September 30, 2017 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 6,700.3 $ — $ 6,700.3 Services — — — 1,683.0 (1.5 ) 1,681.5 Total revenues — — — 8,383.3 (1.5 ) 8,381.8 Cost of sales and fuel (exclusive of items shown separately below) — — — 6,464.3 — 6,464.3 Operating expenses 34.0 — 8.8 878.0 (1.5 ) 919.3 Impairment of long-lived assets — — — 16.0 — 16.0 Gain on sale of assets — — — (0.9 ) — (0.9 ) Operating income (34.0 ) — (8.8 ) 1,025.9 — 983.1 Equity in net earnings from investments 842.0 845.9 854.7 72.1 (2,495.7 ) 119.0 Impairment of equity investments — — — (4.3 ) — (4.3 ) Other income (expense), net (7.4 ) 272.2 272.2 (4.3 ) (544.4 ) (11.7 ) Interest expense, net (93.5 ) (272.2 ) (272.2 ) (268.0 ) 544.4 (361.5 ) Income before income taxes 707.1 845.9 845.9 821.4 (2,495.7 ) 724.6 Income taxes (180.9 ) — — (15.0 ) — (195.9 ) Net income 526.2 845.9 845.9 806.4 (2,495.7 ) 528.7 Less: Net income attributable to noncontrolling interests 201.4 — — 2.5 — 203.9 Net income attributable to ONEOK 324.8 845.9 845.9 803.9 (2,495.7 ) 324.8 Less: Preferred stock dividends 0.5 — — — — 0.5 Net income available to common shareholders $ 324.3 $ 845.9 $ 845.9 $ 803.9 $ (2,495.7 ) $ 324.3 Nine Months Ended September 30, 2016 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 4,757.3 $ — $ 4,757.3 Services — — — 1,510.7 (1.5 ) 1,509.2 Total revenues — — — 6,268.0 (1.5 ) 6,266.5 Cost of sales and fuel (exclusive of items shown separately below) — — — 4,474.7 — 4,474.7 Operating expenses 23.1 — — 823.6 (1.5 ) 845.2 Gain on sale of assets — — — (9.5 ) — (9.5 ) Operating income (23.1 ) — — 979.2 — 956.1 Equity in net earnings from investments 786.8 789.3 789.3 48.2 (2,313.2 ) 100.4 Other income (expense), net 7.8 284.6 284.6 (0.5 ) (569.2 ) 7.3 Interest expense, net (77.1 ) (284.6 ) (284.6 ) (278.4 ) 569.2 (355.5 ) Income before income taxes 694.4 789.3 789.3 748.5 (2,313.2 ) 708.3 Income taxes (149.8 ) — — (7.7 ) — (157.5 ) Income from continuing operations 544.6 789.3 789.3 740.8 (2,313.2 ) 550.8 Income (loss) from discontinued operations, net of tax — — — (1.8 ) — (1.8 ) Net income 544.6 789.3 789.3 739.0 (2,313.2 ) 549.0 Less: Net income attributable to noncontrolling interests 283.1 — — 4.4 — 287.5 Net income attributable to ONEOK $ 261.5 $ 789.3 $ 789.3 $ 734.6 $ (2,313.2 ) $ 261.5 Condensed Consolidating Statements of Comprehensive Income Three Months Ended September 30, 2017 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 165.8 $ 298.3 $ 298.3 $ 288.8 $ (884.7 ) $ 166.5 Other comprehensive income (loss), net of tax Unrealized gains (losses) on derivatives, net of tax 18.4 (61.9 ) (42.4 ) (19.5 ) 84.8 (20.6 ) Realized (gains) losses on derivatives in net income, net of tax 0.6 19.8 15.9 8.6 (31.8 ) 13.1 Change in pension and postretirement benefit plan liability, net of tax 2.0 — — — — 2.0 Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax — (0.3 ) (0.3 ) (0.2 ) 0.6 (0.2 ) Total other comprehensive income (loss) 21.0 (42.4 ) (26.8 ) (11.1 ) 53.6 (5.7 ) Comprehensive income 186.8 255.9 271.5 277.7 (831.1 ) 160.8 Less: Comprehensive income attributable to noncontrolling interests — — — 0.7 — 0.7 Comprehensive income attributable to ONEOK $ 186.8 $ 255.9 $ 271.5 $ 277.0 $ (831.1 ) $ 160.1 Three Months Ended September 30, 2016 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 193.1 $ 274.3 $ 274.3 $ 256.8 $ (804.3 ) $ 194.2 Other comprehensive income (loss), net of tax Unrealized gains (losses) on derivatives, net of tax — 8.5 7.6 14.8 (23.7 ) 7.2 Realized (gains) losses on derivatives in net income, net of tax 0.5 3.0 (1.0 ) 1.0 (0.4 ) 3.1 Change in pension and postretirement benefit plan liability, net of tax 1.6 — — — — 1.6 Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax — (0.7 ) (0.7 ) (1.3 ) 2.1 (0.6 ) Total other comprehensive income (loss) 2.1 10.8 5.9 14.5 (22.0 ) 11.3 Comprehensive income 195.2 285.1 280.2 271.3 (826.3 ) 205.5 Less: Comprehensive income attributable to noncontrolling interests 107.4 — — 1.1 — 108.5 Comprehensive income attributable to ONEOK $ 87.8 $ 285.1 $ 280.2 $ 270.2 $ (826.3 ) $ 97.0 Nine Months Ended September 30, 2017 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 526.2 $ 845.9 $ 845.9 $ 806.4 $ (2,495.7 ) $ 528.7 Other comprehensive income (loss), net of tax Unrealized gains (losses) on derivatives, net of tax 18.1 (38.8 ) (6.1 ) 13.3 12.2 (1.3 ) Realized (gains) losses on derivatives in net income, net of tax 1.6 50.7 38.0 26.0 (76.0 ) 40.3 Change in pension and postretirement benefit plan liability, net of tax 6.1 — — — — 6.1 Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax — (1.5 ) (1.5 ) (1.2 ) 3.0 (1.2 ) Total other comprehensive income (loss) 25.8 10.4 30.4 38.1 (60.8 ) 43.9 Comprehensive income 552.0 856.3 876.3 844.5 (2,556.5 ) 572.6 Less: Comprehensive income attributable to noncontrolling interests 232.4 — — 2.5 — 234.9 Comprehensive income attributable to ONEOK $ 319.6 $ 856.3 $ 876.3 $ 842.0 $ (2,556.5 ) $ 337.7 Nine Months Ended September 30, 2016 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 544.6 $ 789.3 $ 789.3 $ 739.0 $ (2,313.2 ) $ 549.0 Other comprehensive income (loss), net of tax Unrealized gains (losses) on derivatives, net of tax — (98.6 ) (39.4 ) (123.0 ) 177.4 (83.6 ) Realized (gains) losses on derivatives in net income, net of tax 1.6 (17.8 ) (29.5 ) (43.0 ) 75.2 (13.5 ) Change in pension and postretirement benefit plan liability, net of tax 4.7 — — — — 4.7 Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax — (12.1 ) (12.1 ) (22.3 ) 36.3 (10.2 ) Total other comprehensive income (loss) 6.3 (128.5 ) (81.0 ) (188.3 ) 288.9 (102.6 ) Comprehensive income 550.9 660.8 708.3 550.7 (2,024.3 ) 446.4 Less: Comprehensive income attributable to noncontrolling interests 207.6 — — 4.4 — 212.0 Comprehensive income attributable to ONEOK $ 343.3 $ 660.8 $ 708.3 $ 546.3 $ (2,024.3 ) $ 234.4 Condensed Consolidating Balance Sheets September 30, 2017 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total Assets ( Millions of dollars ) Current assets Cash and cash equivalents $ 11.7 $ — $ — $ — $ — $ 11.7 Accounts receivable, net — — — 939.6 — 939.6 Natural gas and natural gas liquids in storage — — — 314.3 — 314.3 Other current assets 10.6 0.3 — 242.4 — 253.3 Total current assets 22.3 0.3 — 1,496.3 — 1,518.9 Property, plant and equipment Property, plant and equipment 139.8 — — 15,224.5 — 15,364.3 Accumulated depreciation and amortization 96.2 — — 2,689.5 — 2,785.7 Net property, plant and equipment 43.6 — — 12,535.0 — 12,578.6 Investments and other assets Investments 5,684.0 3,099.4 7,711.6 809.1 (16,290.4 ) 1,013.7 Intercompany notes receivable 2,831.9 8,605.5 3,993.3 — (15,430.7 ) — Other assets 707.4 0.2 — 1,015.9 (69.9 ) 1,653.6 Total investments and other assets 9,223.3 11,705.1 11,704.9 1,825.0 (31,791.0 ) 2,667.3 Total assets $ 9,289.2 $ 11,705.4 $ 11,704.9 $ 15,856.3 $ (31,791.0 ) $ 16,764.8 Liabilities and equity Current liabilities Current maturities of long-term debt $ — $ 425.0 $ — $ 7.7 $ — $ 432.7 Short-term borrowings 932.3 — — — — 932.3 Accounts payable 6.8 — — 916.0 — 922.8 Other current liabilities 47.8 68.2 — 337.2 — 453.2 Total current liabilities 986.9 493.2 — 1,260.9 — 2,741.0 Intercompany debt — — 8,605.5 6,825.2 (15,430.7 ) — Long-term debt, excluding current maturities 2,726.1 5,335.2 — 30.7 — 8,092.0 Deferred credits and other liabilities 216.7 — — 268.6 (69.9 ) 415.4 Commitments and contingencies Equity Equity excluding noncontrolling interests in consolidated subsidiaries 5,359.5 5,877.0 3,099.4 7,314.0 (16,290.4 ) 5,359.5 Noncontrolling interests in consolidated subsidiaries — — — 156.9 — 156.9 Total equity 5,359.5 5,877.0 3,099.4 7,470.9 (16,290.4 ) 5,516.4 Total liabilities and equity $ 9,289.2 $ 11,705.4 $ 11,704.9 $ 15,856.3 $ (31,791.0 ) $ 16,764.8 December 31, 2016 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total Assets ( Millions of dollars ) Current assets Cash and cash equivalents $ 248.5 $ — $ 0.4 $ — $ — $ 248.9 Accounts receivable, net — — — 872.4 — 872.4 Natural gas and natural gas liquids in storage — — — 140.0 — 140.0 Other current assets 7.2 — — 160.6 — 167.8 Assets of discontinued operations — — — 0.6 — 0.6 Total current assets 255.7 — 0.4 1,173.6 — — 1,429.7 Property, plant and equipment Property, plant and equipment 139.8 — — 14,938.7 — 15,078.5 Accumulated depreciation and amortization 90.4 — — 2,416.7 — 2,507.1 Net property, plant and equipment 49.4 — — 12,522.0 — 12,571.4 Investments and other assets Investments 2,931.9 3,222.1 6,805.4 631.1 (12,631.7 ) 958.8 Intercompany notes receivable 205.2 10,615.0 7,031.3 — (17,851.5 ) — Other assets 103.4 47.5 — 1,028.0 — 1,178.9 Total investments and other assets 3,240.5 13,884.6 13,836.7 1,659.1 (30,483.2 ) 2,137.7 Total assets $ 3,545.6 $ 13,884.6 $ 13,837.1 $ 15,354.7 $ (30,483.2 ) $ 16,138.8 Liabilities and equity Current liabilities Current maturities of long-term debt $ 3.0 $ 400.0 $ — $ 7.7 $ — $ 410.7 Short-term borrowings — 1,110.3 — — — 1,110.3 Accounts payable 13.0 — — 861.7 — 874.7 Other current liabilities 44.7 99.9 — 296.5 — 441.1 Total current liabilities 60.7 1,610.2 — 1,165.9 — 2,836.8 Intercompany debt — — 10,615.0 7,236.5 (17,851.5 ) — Long-term debt, excluding current maturities 1,628.7 6,254.7 — 36.6 — 7,920.0 Deferred credits and other liabilities 1,667.5 — — 285.6 — 1,953.1 Commitments and contingencies Equity Equity excluding noncontrolling interests in consolidated subsidiaries 188.7 6,019.7 3,222.1 6,472.0 (15,713.8 ) 188.7 Noncontrolling interests in consolidated subsidiaries — — — 158.1 3,082.1 3,240.2 Total equity 188.7 6,019.7 3,222.1 6,630.1 (12,631.7 ) 3,428.9 Total liabilities and equity $ 3,545.6 $ 13,884.6 $ 13,837.1 $ 15,354.7 $ (30,483.2 ) $ 16,138.8 Condensed Consolidating Statements of Cash Flows Nine Months Ended September 30, 2017 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 620.8 $ 994.3 $ 42.1 $ 1,005.8 $ (1,727.0 ) $ 936.0 Investing activities Capital expenditures (0.5 ) — — (329.9 ) — (330.4 ) Contributions to unconsolidated affiliates — — (83.0 ) (4.7 ) — (87.7 ) Other investing activities — — 11.2 12.3 — 23.5 Cash used in investing activities (0.5 ) — (71.8 ) (322.3 ) — (394.6 ) Financing activities Dividends paid (543.4 ) (999.0 ) (999.0 ) — 1,998.0 (543.4 ) Distributions to noncontrolling interests — — — (4.1 ) (271.0 ) (275.1 ) Intercompany borrowings (advances), net (2,376.9 ) 2,022.2 1,028.3 (673.6 ) — — Borrowing (repayment) of short-term borrowings, net 932.3 (1,110.3 ) — — — (178.0 ) Issuance of long-term debt, net of discounts 1,190.1 — — — — 1,190.1 Repayment of long-term debt (87.1 ) (900.0 ) — (5.8 ) — (992.9 ) Issuance of common stock 45.8 — — — — 45.8 Other (17.9 ) (7.2 ) — — — (25.1 ) Cash provided by (used in) financing activities (857.1 ) (994.3 ) 29.3 — (683.5 ) 1,727.0 (778.6 ) Change in cash and cash equivalents (236.8 ) — (0.4 ) — — (237.2 ) Cash and cash equivalents at beginning of period 248.5 — 0.4 — — 248.9 Cash and cash equivalents at end of period $ 11.7 $ — $ — $ — $ — $ 11.7 Nine Months Ended September 30, 2016 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 546.3 $ 998.3 $ 52.3 $ 916.7 $ (1,591.6 ) $ 922.0 Investing activities Capital expenditures (0.1 ) — — (491.4 ) — (491.5 ) Other investing activities — — 30.0 (23.1 ) — 6.9 Cash provided by (used in) investing activities (0.1 ) — 30.0 (514.5 ) — (484.6 ) Financing activities Dividends paid (388.1 ) (999.0 ) (999.0 ) — 1,998.0 (388.1 ) Distributions to noncontrolling interests — — — (6.1 ) (406.4 ) (412.5 ) Intercompany borrowings (advances), net (33.1 ) (493.7 ) 917.1 (390.3 ) — — Borrowing (repayment) of short-term borrowings, net — 147.2 — — — 147.2 Issuance of long-term debt, net of discounts — 1,000.0 — — — 1,000.0 Debt financing costs — (2.8 ) — — — (2.8 ) Repayment of long-term debt (0.3 ) (650.0 ) — (5.8 ) — (656.1 ) Issuance of common stock 14.9 — — — — 14.9 Cash used in financing activities (406.6 ) (998.3 ) (81.9 ) (402.2 ) 1,591.6 (297.4 ) Change in cash and cash equivalents 139.6 — 0.4 — — 140.0 Change in cash and cash equivalents included in discontinued operations (0.2 ) — — — — (0.2 ) Change in cash and cash equivalents included in continuing operations 139.4 — 0.4 — — 139.8 Cash and cash equivalents at beginning of period 92.5 — 5.1 — — 97.6 Cash and cash equivalents at end of period $ 231.9 $ — $ 5.5 $ — $ — $ 237.4

SUMMARY OF SIGNIFICANT ACCOUN24

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
	Sep. 30, 2017
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Basis of Accounting, Policy [Policy Text Block]	Our accompanying unaudited consolidated financial statements have been prepared pursuant to the rules and regulations of the SEC. These statements have been prepared in accordance with GAAP and reflect all adjustments that, in our opinion, are necessary for a fair statement of the results for the interim periods presented. All such adjustments are of a normal recurring nature. The 2016 year-end consolidated balance sheet data was derived from our audited financial statements but does not include all disclosures required by GAAP. Certain reclassifications have been made in the prior-year financial statements to conform to the current-year presentation. These unaudited consolidated financial statements should be read in conjunction with our audited consolidated financial statements in our Annual Report and our Current Report on Form 8-K filed on July 6, 2017, which updates Item 8 in our Annual Report.
Discontinued Operations, Policy [Policy Text Block]	Discontinued Operations - Beginning in 2017, the results of operations and financial position of our former energy services business are no longer reflected as discontinued operations in our Consolidated Financial Statements and Notes to the Consolidated Financial Statements, as they are not material.
New Accounting Pronouncements, Policy [Policy Text Block]	Recently Issued Accounting Standards Update - Changes to GAAP are established by the Financial Accounting Standards Board (FASB) in the form of ASUs to the FASB Accounting Standards Codification. We consider the applicability and impact of all ASUs. ASUs not listed below were assessed and determined to be either not applicable or clarifications of ASUs listed below. The following tables provide a brief description of recent accounting pronouncements and our analysis of the effects on our financial statements: Standard Description Date of Adoption Effect on the Financial Statements or Other Significant Matters Standards that were adopted ASU 2015-11, “Inventory (Topic 330): Simplifying the Measurement of Inventory” The standard 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. First quarter 2017 As a result of adopting this guidance, we updated our accounting policy for inventory valuation accordingly. The financial impact of adopting this guidance was not material. ASU 2016-05, “Derivatives and Hedging (Topic 815): Effect of Derivative Contract Novations on Existing Hedge Accounting Relationships” The standard clarifies that a change in the counterparty to a derivative instrument that has been designated as the hedging instrument under Topic 815 does not, in and of itself, require dedesignation of that hedging relationship provided that all other hedge accounting criteria continue to be met. First quarter 2017 The impact of adopting this standard was not material. ASU 2016-06, “Derivatives and Hedging (Topic 815): Contingent Put and Call Options in Debt Instruments” The standard clarifies the requirements for assessing whether a contingent call (put) option that can accelerate the payment of principal on a debt instrument is clearly and closely related to its debt host. First quarter 2017 The impact of adopting this standard was not material. ASU 2016-09, “Compensation - Stock Compensation (Topic 718): Improvements to Employee Share-Based Payment Accounting” The standard provides simplified accounting for share-based payment transactions in relation to income tax consequences, classification of awards as either equity or liabilities, and classification on the statement of cash flows. First quarter 2017 As a result of adopting this guidance, we recorded an adjustment increasing beginning retained earnings and deferred tax assets in the first quarter 2017 of approximately $73 million to recognize previously unrecognized cumulative excess tax benefits related to share-based payments on a modified retrospective basis. Beginning in January 2017, all share-based payment tax effects are recorded in earnings. The other effects of adopting this standard were not material. Standard Description Date of Adoption Effect on the Financial Statements or Other Significant Matters Standards that are not yet adopted ASU 2014-09, “Revenue from Contracts with Customers (Topic 606)” The standard 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. First quarter 2018 We expect to adopt this standard on January 1, 2018, using the modified retrospective method. We have not completed our analysis to quantify the cumulative effect of adoption adjustment to retained earnings, but do not expect it to be material. For many of our contracts, we do not expect material changes in our accounting policies or revenue recognition. However, under Topic 606, we expect that a significant portion of services revenues will be presented as reduction of cost of sales and fuel, for certain midstream service contracts where we also purchase raw natural gas or unfractionated NGLs. Under Topic 606, these contracts are considered supplier contracts rather than contracts with customers. We have not completed our analysis to quantify the amount expected to be reclassified to cost of sales and fuel from services revenue, but expect it to be material. We do not believe the adoption of Topic 606 will have a material impact on operating income or net income. We are developing required disclosures and expect to disaggregate revenues on a segment basis similar to our current presentation in Management’s Discussion and Analysis. We expect our disclosure of unsatisfied performance obligations to relate primarily to firm transportation contracts. We do not expect a material contract asset balance and expect our contract liability balance to include storage contracts that have been prepaid by customers and contributions in aid of construction received from customers. ASU 2016-01, “Financial Instruments-Overall (Subtopic 825-10): Recognition and Measurement of Financial Assets and Financial Liabilities” The standard 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. First quarter 2018 We do not have any equity investments classified as available-for-sale or accounted for using the cost method, therefore, we do not expect adoption of this standard to have a material impact on us. ASU 2016-15, “Statement of Cash Flows (Topic 230): Classification of Certain Cash Receipts and Cash Payments” The standard clarifies the classification of certain cash receipts and cash payments on the statement of cash flows where diversity in practice has been identified. First quarter 2018 We do not expect the adoption of this standard to materially impact us. ASU 2017-07, “Compensation - Retirement Benefits (Topic 715): Improving the Presentation of Net Periodic Pension Cost and Net Periodic Postretirement Benefit Cost” The standard requires the service cost component of net benefit cost to be reported in the same line item or items as other compensation costs from services rendered by the pertinent employees during the period. The other components of net benefit cost are required to be presented in the income statement separately from the service cost component and outside a subtotal of income from operations. First quarter 2018 We do not expect the adoption of this standard to materially impact us. Standard Description Date of Adoption Effect on the Financial Statements or Other Significant Matters Standards that are not yet adopted ( continued ) ASU 2016-02, “Leases (Topic 842)” The standard requires the recognition of lease assets and lease liabilities by lessees for those leases classified as operating leases under previous GAAP. It also requires qualitative disclosures along with specific quantitative disclosures by lessees and lessors to meet the objective of enabling users of financial statements to assess the amount, timing and uncertainty of cash flows arising from leases. First quarter 2019 We are evaluating our current leases and other contracts that may be considered leases under the new standard and the impact on our internal controls, accounting policies and financial statements and disclosures. ASU 2017-12, “Derivatives and Hedging (Topic 815): Targeted Improvements to Accounting for Hedging Activities The standard more closely aligns hedge accounting with companies’ existing risk-management strategies by expanding the strategies eligible for hedge accounting, relaxing the timing requirements of hedge documentation and effectiveness assessments, permitting in certain cases, the use of qualitative assessments on an ongoing basis to assess hedge effectiveness, and requiring new disclosures and presentation. First Quarter 2019 We are evaluating the timing of adoption and the impact of this standard on us. At adoption, we expect to record a cumulative-effect adjustment to the opening balance of retained earnings and other comprehensive income to eliminate the separate measurement of hedge ineffectiveness, which we do not expect to be material. We expect immaterial changes to disclosures as a result of adopting this standard. ASU 2016-13, “Financial Instruments - Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments” The standard requires a financial asset (or a group of financial assets) measured at amortized cost basis to be presented net of the allowance for credit losses to reflect the net carrying value at the amount expected to be collected on the financial asset; and the initial allowance for credit losses for purchased financial assets, including available-for-sale debt securities, to be added to the purchase price rather than being reported as a credit loss expense. First quarter 2020 We do not expect the adoption of this standard to materially impact us. ASU 2017-04, “Intangibles- Goodwill and Other (Topic 350): Simplifying the Test for Goodwill Impairment” The standard simplifies the subsequent measurement of goodwill by eliminating the requirement to calculate the implied fair value of goodwill under step 2. Instead, an entity will recognize an impairment charge for the amount by which the carrying amount exceeds the reporting unit’s fair value. The standard does not change step zero or step 1 assessments. First quarter 2020 We do not expect the adoption of this standard to materially impact us.
Goodwill and Intangible Assets, Policy [Policy Text Block]	Goodwill Impairment Review - We assess our goodwill for impairment at least annually as of July 1. At July 1, 2017, we assessed qualitative factors to determine whether it was more likely than not that the fair value of each of our reporting units was less than its carrying amount. After assessing qualitative factors (including macroeconomic conditions, industry and market considerations, cost factors and overall financial performance), we determined that it was more likely than not that the fair value of each reporting unit was greater than its respective carrying value, that no further testing was necessary and that goodwill was not considered impaired.

FAIR VALUE MEASUREMENTS FAIR VA

FAIR VALUE MEASUREMENTS FAIR VALUE MEASUREMENTS (Policies)	9 Months Ended
	Sep. 30, 2017
Fair Value Accounting Policy [Abstract]
Fair Value of Financial Instruments, Policy [Policy Text Block]	Determining Fair Value - We define fair value as the price that would be received from the sale of an asset or the transfer of a liability in an orderly transaction between market participants at the measurement date. We use market and income approaches to determine the fair value of our assets and liabilities and consider the markets in which the transactions are executed. We measure the fair value of a group of financial assets and liabilities consistent with how a market participant would price the net risk exposure at the measurement date. While many of the contracts in our derivative 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 the LIBOR interest-rate swaps market. We also take into consideration the potential impact on market prices of liquidating positions in an orderly manner over a reasonable period of time under current market conditions. We consider current market data in evaluating counterparties’, as well as our own, nonperformance risk, net of collateral, by using specific and sector bond yields and monitoring the credit default swap markets. Although we use our best estimates to determine the fair value of the derivative contracts we have executed, the ultimate market prices realized could differ from our estimates, and the differences could be material. The fair value of our forward-starting interest-rate swaps are determined using financial models that incorporate the implied forward LIBOR yield curve for the same period as the future interest-rate swap settlements. Fair Value Hierarchy - At each balance sheet date, we utilize a fair value hierarchy to classify fair value amounts recognized or disclosed in our financial statements based on the observability of inputs used to estimate such fair value. The levels of the hierarchy are described below: • Level 1 - fair value measurements are based on unadjusted quoted prices for identical securities in active markets, including NYMEX-settled prices. These balances are comprised predominantly of exchange-traded derivative contracts for natural gas and crude oil. • Level 2 - fair value measurements are based on significant observable pricing inputs, such as NYMEX-settled prices for natural gas and crude oil, and financial models that utilize implied forward LIBOR yield curves for interest-rate swaps. • Level 3 - fair value measurements are based on inputs that may include one or more unobservable inputs, including internally developed natural gas basis and NGL price curves that incorporate observable and unobservable market data from broker quotes, third-party pricing services, market volatilities derived from the most recent NYMEX close spot prices and forward LIBOR curves, and adjustments for the credit risk of our counterparties. We corroborate the data on which our fair value estimates are based using our market knowledge of recent transactions, analysis of historical correlations and validation with independent broker quotes. These balances categorized as Level 3 are composed 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.

EQUITY (Policies)

EQUITY (Policies)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Partnership agreement	Cash Distributions - Prior to the consummation of the Merger Transaction, we received distributions from ONEOK Partners on our common and Class B units and our 2 percent general partner interest, which included our incentive distribution rights.

SEGMENTS SEGMENTS (Policies)

SEGMENTS SEGMENTS (Policies)	9 Months Ended
	Sep. 30, 2017
Segment Reporting [Abstract]
Segment Accounting Policy [Policy Text Block]	Accounting Policies - The accounting policies of the segments are described in Note A of the Notes to Consolidated Financial Statements in our Annual Report. Our chief operating decision-maker reviews the financial performance of each of our three segments, as well as our financial performance as a whole, on a regular basis. Adjusted EBITDA by segment is utilized in this evaluation. We believe this financial measure is useful to investors because it and similar measures are used by many companies in our industry as a measurement of financial performance and are commonly employed by financial analysts and others to evaluate our financial performance and to compare financial performance among companies in our industry. Adjusted EBITDA for each segment is defined as net income adjusted for interest expense, depreciation and amortization, noncash impairment charges, income taxes, allowance for equity funds used during construction, noncash compensation and other noncash items. This calculation may not be comparable with similarly titled measures of other companies.

ONEOK PARTNERS ACQUISITION (Tab

ONEOK PARTNERS ACQUISITION (Tables)	6 Months Ended
	Jun. 30, 2017
Business Acquisition, Pro Forma Information, Nonrecurring Adjustment [Line Items]
Cash Flow, Supplemental Disclosures [Text Block]	Our noncash balance sheet activity related to the Merger Transaction is as follows (in millions): Common stock $ 1.7 Paid-in capital $ 5,228.6 Accumulated other comprehensive loss $ (40.3 ) Noncontrolling interests in consolidated subsidiaries $ (3,043.5 ) Deferred income taxes $ (2,146.5 )

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
	Sep. 30, 2017
Fair Value Disclosures [Abstract]
Recurring Fair Value Measurements	The following tables set forth our recurring fair value measurements for the periods indicated: September 30, 2017 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net (b) ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 1,237 $ — $ 16,629 $ 17,866 $ (17,839 ) $ 27 Interest-rate contracts — 45,684 — 45,684 — 45,684 Total derivative assets $ 1,237 $ 45,684 $ 16,629 $ 63,550 $ (17,839 ) $ 45,711 Derivative liabilities Commodity contracts Financial contracts $ (4,415 ) $ — $ (39,052 ) $ (43,467 ) $ 43,268 $ (199 ) Physical contracts — — (4,083 ) (4,083 ) — (4,083 ) Total derivative liabilities $ (4,415 ) $ — $ (43,135 ) $ (47,550 ) $ 43,268 $ (4,282 ) (a) - Derivative assets and liabilities are presented in our Consolidated Balance Sheets on a net basis. We net derivative assets and liabilities when a legally enforceable master-netting arrangement exists between the counterparty to a derivative contract and us. At September 30, 2017 , we held no cash and posted $52.8 million of cash with various counterparties, including $25.4 million of cash collateral that is offsetting derivative net liability positions under master-netting arrangements in the table above. The remaining $27.4 million of cash collateral in excess of derivative net liability positions is included in other current assets in our Consolidated Balance Sheets. (b) - Included in other current assets, other assets, other current liabilities or other deferred credits in our Consolidated Balance Sheets. December 31, 2016 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net (b) ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 1,147 $ — $ 4,564 $ 5,711 $ (4,760 ) $ 951 Interest rate contracts — 47,457 — 47,457 — 47,457 Total derivative assets $ 1,147 $ 47,457 $ 4,564 $ 53,168 $ (4,760 ) $ 48,408 Derivative liabilities Commodity contracts Financial contracts $ (31,458 ) $ — $ (24,861 ) $ (56,319 ) $ 56,319 $ — Physical contracts — — (3,022 ) (3,022 ) — (3,022 ) Interest-rate contracts — (12,795 ) — (12,795 ) — (12,795 ) Total derivative liabilities $ (31,458 ) $ (12,795 ) $ (27,883 ) $ (72,136 ) $ 56,319 $ (15,817 ) (a) - Derivative assets and liabilities are presented in our Consolidated Balance Sheets on a net basis. We net derivative assets and liabilities when a legally enforceable master-netting arrangement exists between the counterparty to a derivative contract and us. At December 31, 2016 , we held no cash and posted $67.7 million of cash with various counterparties, including $51.6 million of cash collateral that is offsetting derivative net liability positions under master-netting arrangements in the table above. The remaining $16.1 million of cash collateral in excess of derivative net liability positions is included in other current assets in our Consolidated Balance Sheets. (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: Three Months Ended Nine Months Ended September 30, September 30, Derivative Assets (Liabilities) 2017 2016 2017 2016 ( Thousands of dollars ) Net assets (liabilities) at beginning of period $ 750 $ (14,021 ) $ (23,319 ) $ 7,331 Total realized/unrealized gains (losses): Included in earnings (a) (675 ) 920 (417 ) 492 Included in other comprehensive income (loss) (26,581 ) 3,038 (2,770 ) (17,886 ) Net assets (liabilities) at end of period $ (26,506 ) $ (10,063 ) $ (26,506 ) $ (10,063 ) (a) - Included in commodity sales revenues in our Consolidated Statements of Income.

RISK MANAGEMENT AND HEDGING A30

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES (Tables)	9 Months Ended
	Sep. 30, 2017
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivatives	The following table sets forth the fair values of derivative instruments for the periods indicated: September 30, 2017 December 31, 2016 Location in our Consolidated Balance Sheets Assets (Liabilities) Assets (Liabilities) ( Thousands of dollars ) Derivatives designated as hedging instruments Commodity contracts Financial contracts Other current assets/other current liabilities $ 9,180 $ (33,500 ) $ 1,155 $ (49,938 ) Other assets/other deferred credits 2,098 (2,815 ) 210 (2,142 ) Physical contracts Other current liabilities — (3,600 ) — (3,022 ) Other deferred credits — (483 ) — — Interest-rate contracts Other current assets/other current liabilities 252 — — (12,795 ) Other assets 45,432 — 47,457 — Total derivatives designated as hedging instruments 56,962 (40,398 ) 48,822 (67,897 ) Derivatives not designated as hedging instruments Commodity contracts Financial contracts Other current assets/other current liabilities 5,862 (6,444 ) 4,346 (4,239 ) Other assets/other deferred credits 726 (708 ) — — Total derivatives not designated as hedging instruments 6,588 (7,152 ) 4,346 (4,239 ) Total derivatives $ 63,550 $ (47,550 ) $ 53,168 $ (72,136 )
Notional Amounts of Derivative Instruments	The following table sets forth the notional quantities for derivative instruments held for the periods indicated: September 30, 2017 December 31, 2016 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 — (27.6 ) — (38.4 ) - Natural gas ( Bcf ) Put options 9.0 — 49.5 — - Crude oil and NGLs ( MMBbl ) Futures, forwards and swaps 2.8 (10.3 ) — (3.6 ) Basis - Natural gas ( Bcf ) Futures and swaps — (27.6 ) — (38.4 ) Interest-rate contracts ( Millions of dollars ) Swaps $ 1,750.0 $ — $ 2,150.0 $ — Derivatives not designated as hedging instruments: Fixed price -Natural gas ( Bcf ) Futures and swaps 2.7 — 0.4 — - NGLs ( MMBbl ) Futures, forwards and swaps 1.2 (2.2 ) 0.5 (0.7 ) Basis - Natural gas ( Bcf ) Futures and swaps 2.7 — 0.4 —
Schedule of Cash Flow Hedging Instruments Effect on Comprehensive Income (Loss)	The following table sets forth the unrealized effect of cash flow hedges recognized in other comprehensive income (loss) for the periods indicated: Three Months Ended Nine Months Ended Derivatives in Cash Flow Hedging Relationships September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Commodity contracts $ (42,450 ) $ 7,580 $ (6,123 ) $ (39,396 ) Interest-rate contracts 9,613 958 (3,853 ) (59,217 ) Total unrealized gain (loss) recognized in other comprehensive income (loss) on derivatives (effective portion) $ (32,837 ) $ 8,538 $ (9,976 ) $ (98,613 )
Schedule of Cash Flow Hedging Instruments Effect on Income	The following table sets forth the effect of cash flow hedges in our Consolidated Statements of Income for the periods indicated: Derivatives in Cash Flow Hedging Relationships Location of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Net Income (Effective Portion) Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Commodity contracts Commodity sales revenues $ (15,913 ) $ 908 $ (38,028 ) $ 29,456 Interest-rate contracts Interest expense (4,820 ) (4,802 ) (15,321 ) (14,302 ) Total gain (loss) reclassified from accumulated other comprehensive loss into net income on derivatives (effective portion) $ (20,733 ) $ (3,894 ) $ (53,349 ) $ 15,154

DEBT DEBT (Tables)

DEBT DEBT (Tables)	9 Months Ended
	Sep. 30, 2017
Debt Instrument [Line Items]
Debt [Table Text Block]	The following table sets forth our consolidated debt for the periods indicated: September 30, December 31, ( Thousands of dollars ) ONEOK Senior unsecured obligations: Commercial paper outstanding, bearing a weighted-average interest rate of 1.93% (a) $ 932,250 $ — $700,000 at 4.25% due February 2022 547,397 547,397 $500,000 at 7.5% due September 2023 500,000 500,000 $500,000 at 4.0% due July 2027 500,000 — $100,000 at 6.5% due September 2028 — 87,126 $100,000 at 6.875% due September 2028 100,000 100,000 $400,000 at 6.0% due June 2035 400,000 400,000 $700,000 at 4.95% due July 2047 700,000 — ONEOK Partners Commercial paper outstanding (a) — 1,110,277 Senior unsecured obligations: $400,000 at 2.0% due October 2017 — 400,000 $425,000 at 3.2% due September 2018 425,000 425,000 $1,000,000 term loan, variable rate, due January 2019 500,000 1,000,000 $500,000 at 8.625% due March 2019 500,000 500,000 $300,000 at 3.8% due March 2020 300,000 300,000 $900,000 at 3.375 % due October 2022 900,000 900,000 $425,000 at 5.0 % due September 2023 425,000 425,000 $500,000 at 4.9 % due March 2025 500,000 500,000 $600,000 at 6.65% due October 2036 600,000 600,000 $600,000 at 6.85% due October 2037 600,000 600,000 $650,000 at 6.125% due February 2041 650,000 650,000 $400,000 at 6.2% due September 2043 400,000 400,000 Guardian Pipeline Weighted average 7.85% due December 2022 38,520 44,257 Total debt 9,518,167 9,489,057 Unamortized portion of terminated swaps 18,897 20,186 Unamortized debt issuance costs and discounts (80,164 ) (68,320 ) Current maturities of long-term debt (432,650 ) (410,650 ) Short-term borrowings (b) (932,250 ) (1,110,277 ) Long-term debt $ 8,092,000 $ 7,919,996 (a) - In July 2017, the commercial paper outstanding under the ONEOK Partners commercial paper program was repaid as it matured with a combination of proceeds from new issuances from ONEOK’s recently established $2.5 billion commercial paper program, cash on hand and proceeds from our July 2017 $1.2 billion senior notes issuance. The $2.4 billion ONEOK Partners commercial paper program was terminated in July 2017. (b) - Individual issuances of commercial paper under our commercial paper program generally mature in 90 days or less. These issuances are supported by and reduce the borrowing capacity under the 2017 Credit Agreement.

EQUITY (Tables)

EQUITY (Tables)	9 Months Ended
	Sep. 30, 2017
Equity [Abstract]
Schedule of distributions made to general or limited partner	The following table sets forth ONEOK Partners’ distributions declared and paid during the periods prior to the closing of the Merger Transaction on June 30, 2017: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 ( Thousands, except per unit amounts ) Distribution per unit $ — $ 0.79 $ 1.58 $ 2.37 General partner distributions $ — $ 6,660 $ 13,320 $ 19,980 Incentive distributions — 100,538 201,076 301,614 Distributions to general partner — 107,198 214,396 321,594 Limited partner distributions to ONEOK — 90,323 180,646 270,969 Limited partner distributions to other unitholders — 135,480 270,959 406,439 Total distributions paid $ — $ 333,001 $ 666,001 $ 999,002

ACCUMULATED OTHER COMPREHENSI33

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ACCUMULATED OTHER COMPREHENSIVE INCOME (Tables)	9 Months Ended
	Sep. 30, 2017
Accumulated Other Comprehensive Income (Loss)	The following table sets forth the balance in accumulated other comprehensive loss for the period indicated: Unrealized Gains (Losses) on Risk- Management Assets/Liabilities (a) Pension and Postretirement Benefit Plan Obligations (a) (b) Unrealized Gains (Losses) on Risk- Management Assets/Liabilities of Unconsolidated Affiliates (a) Accumulated Other Comprehensive Loss (a) ( Thousands of dollars ) January 1, 2017 $ (52,155 ) $ (101,236 ) $ (959 ) $ (154,350 ) Other comprehensive income (loss) before reclassifications (14,892 ) 8 (588 ) (15,472 ) Amounts reclassified from accumulated other comprehensive loss 22,126 6,114 99 28,339 Impact of Merger Transaction (Note B) (c) (40,288 ) — — (40,288 ) Net current-period other comprehensive income (loss) attributable to ONEOK (33,054 ) 6,122 (489 ) (27,421 ) September 30, 2017 $ (85,209 ) $ (95,114 ) $ (1,448 ) $ (181,771 ) (a) - All amounts are presented net of tax. (b) - Includes amounts related to supplemental executive retirement plan. (c) - Includes the remaining portion of ONEOK Partners’ accumulated other comprehensive loss at June 30, 2017, that we acquired in the Merger Transaction, related to commodity and interest-rate contracts.
Reclassification out of Accumulated Other Comprehensive Income (Loss)	The following table sets forth the effect of reclassifications from accumulated other comprehensive loss in our Consolidated Statements of Income for the periods indicated: Details about Accumulated Other Components Three Months Ended Nine Months Ended Affected Line Item in the Statements of Income September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Unrealized gains (losses) on risk-management assets/liabilities Commodity contracts $ (15,913 ) $ 908 $ (38,028 ) $ 29,456 Commodity sales revenues Interest-rate contracts (4,820 ) (4,802 ) (15,321 ) (14,302 ) Interest expense (20,733 ) (3,894 ) (53,349 ) 15,154 Income before income taxes 7,671 811 13,077 (1,658 ) Income tax expense (13,062 ) (3,083 ) (40,272 ) 13,496 Net income Noncontrolling interests — (1,774 ) (18,146 ) 10,459 Less: Net income attributable to noncontrolling interests $ (13,062 ) $ (1,309 ) $ (22,126 ) $ 3,037 Net income attributable to ONEOK Pension and postretirement benefit plan obligations (a) Amortization of net loss $ (3,811 ) $ (2,999 ) $ (11,435 ) $ (8,994 ) Amortization of unrecognized prior service cost 415 416 1,245 1,246 (3,396 ) (2,583 ) (10,190 ) (7,748 ) Income before income taxes 1,358 1,033 4,076 3,099 Income tax expense $ (2,038 ) $ (1,550 ) $ (6,114 ) $ (4,649 ) Net income attributable to ONEOK Unrealized gains (losses) on risk-management assets/liabilities of unconsolidated affiliates $ (83 ) $ — $ (264 ) $ — Equity in net earnings from investments 31 — 59 — Income tax expense (52 ) — (205 ) — Net income Noncontrolling interests — — (106 ) — Less: Net income attributable to noncontrolling interests $ (52 ) $ — $ (99 ) $ — Net income attributable to ONEOK Total reclassifications for the period attributable to ONEOK $ (15,152 ) $ (2,859 ) $ (28,339 ) $ (1,612 ) Net income attributable to ONEOK (a) - These components of accumulated other comprehensive loss are included in the computation of net periodic benefit cost. See Note I for additional detail of our net periodic benefit cost.

EARNINGS PER SHARE EARNINGS P34

EARNINGS PER SHARE EARNINGS PER SHARE (Tables)	9 Months Ended
	Sep. 30, 2017
Earnings Per Share [Abstract]
Earnings Per Share	The following tables set forth the computation of basic and diluted EPS from continuing operations for the periods indicated: Three Months Ended September 30, 2017 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS from continuing operations Income from continuing operations attributable to ONEOK available for common stock $ 165,466 380,907 $ 0.43 Diluted EPS from continuing operations Effect of dilutive securities — 2,512 Income from continuing operations attributable to ONEOK available for common stock and common stock equivalents $ 165,466 383,419 $ 0.43 Three Months Ended September 30, 2016 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS from continuing operations Income from continuing operations attributable to ONEOK available for common stock $ 92,720 211,309 $ 0.44 Diluted EPS from continuing operations Effect of dilutive securities — 1,561 Income from continuing operations attributable to ONEOK available for common stock and common stock equivalents $ 92,720 212,870 $ 0.44 Nine Months Ended September 30, 2017 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS from continuing operations Income from continuing operations attributable to ONEOK available for common stock $ 324,303 268,108 $ 1.21 Diluted EPS from continuing operations Effect of dilutive securities — 2,241 Income from continuing operations attributable to ONEOK available for common stock and common stock equivalents $ 324,303 270,349 $ 1.20 Nine Months Ended September 30, 2016 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS from continuing operations Income from continuing operations attributable to ONEOK available for common stock $ 263,289 211,038 $ 1.25 Diluted EPS from continuing operations Effect of dilutive securities — 1,085 Income from continuing operations attributable to ONEOK available for common stock and common stock equivalents $ 263,289 212,123 $ 1.24

EMPLOYEE BENEFIT PLANS EMPLOY35

EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS (Tables)	9 Months Ended
	Sep. 30, 2017
Defined Benefit Plan [Abstract]
Components of net periodic benefit cost for pension and postretirement benefit plans	The following tables set forth the components of net periodic benefit cost for our pension and postretirement benefit plans for our continuing operations for the periods indicated: Pension Benefits Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Components of net periodic benefit cost Service cost $ 1,721 $ 1,622 $ 5,165 $ 4,866 Interest cost 4,655 4,946 13,965 14,840 Expected return on plan assets (5,336 ) (5,077 ) (16,008 ) (15,231 ) Amortization of net loss 3,392 2,737 10,176 8,210 Net periodic benefit cost $ 4,432 $ 4,228 $ 13,298 $ 12,685 Postretirement Benefits Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Components of net periodic benefit cost Service cost $ 165 $ 149 $ 495 $ 447 Interest cost 565 601 1,695 1,803 Expected return on plan assets (564 ) (531 ) (1,692 ) (1,593 ) Amortization of prior service credit (415 ) (416 ) (1,245 ) (1,246 ) Amortization of net loss 419 262 1,259 784 Net periodic benefit cost $ 170 $ 65 $ 512 $ 195

UNCONSOLIDATED AFFILIATES (Tabl

UNCONSOLIDATED AFFILIATES (Tables)	9 Months Ended
	Sep. 30, 2017
Equity In Net Earnings From Investments
Schedule of Equity Method Investments [Line Items]
Schedule of Equity Method Investments [Table Text Block]	The following table sets forth our equity in net earnings from investments for the periods indicated: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Northern Border Pipeline $ 16,440 $ 17,854 $ 50,879 $ 52,251 Overland Pass Pipeline Company 15,793 13,886 44,243 40,798 Other 7,825 3,415 23,863 7,392 Equity in net earnings from investments $ 40,058 $ 35,155 $ 118,985 $ 100,441 Impairment of equity investments $ (4,270 ) $ — $ (4,270 ) $ —
Unconsolidated Affiliates Financial Information
Schedule of Equity Method Investments [Line Items]
Schedule of Equity Method Investments [Table Text Block]	The following table sets forth summarized combined financial information of our unconsolidated affiliates for the periods indicated: Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 ( Thousands of dollars ) Income Statement Operating revenues $ 163,627 $ 143,967 $ 475,510 $ 423,170 Operating expenses $ 69,740 $ 66,490 $ 206,141 $ 191,863 Net income $ 87,330 $ 72,672 $ 260,533 $ 214,129 Distributions paid to us $ 49,414 $ 40,822 $ 146,094 $ 149,399

SEGMENTS (Tables)

SEGMENTS (Tables)	9 Months Ended
	Sep. 30, 2017
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Segments	The following tables set forth certain selected financial information for our operating segments for the periods indicated: Three Months Ended Natural Gas Natural Gas Natural Gas Total ( Thousands of dollars ) Sales to unaffiliated customers $ 453,432 $ 2,348,052 $ 104,340 $ 2,905,824 Intersegment revenues 329,496 153,927 2,098 485,521 Total revenues 782,928 2,501,979 106,438 3,391,345 Cost of sales and fuel (exclusive of depreciation and items shown separately below) (566,988 ) (2,136,207 ) (10,614 ) (2,713,809 ) Operating costs (80,197 ) (90,234 ) (29,838 ) (200,269 ) Equity in net earnings from investments 3,433 15,287 21,338 40,058 Other 2,774 3,094 203 6,071 Segment adjusted EBITDA $ 141,950 $ 293,919 $ 87,527 $ 523,396 Depreciation and amortization $ (46,842 ) $ (41,929 ) $ (12,765 ) $ (101,536 ) Impairment of long-lived assets and equity investments $ (20,240 ) $ — $ — $ (20,240 ) Capital expenditures $ 85,542 $ 27,024 $ 18,811 $ 131,377 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $293.1 million , of which $250.2 million related to sales within the segment and cost of sales and fuel of $124.2 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $65.6 million and cost of sales and fuel of $10.5 million . Three Months Ended September 30, 2017 Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated Sales to unaffiliated customers $ 2,905,824 $ 542 $ 2,906,366 Intersegment revenues 485,521 (485,521 ) — Total revenues $ 3,391,345 $ (484,979 ) $ 2,906,366 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (2,713,809 ) $ 484,393 $ (2,229,416 ) Operating costs $ (200,269 ) $ (6,781 ) $ (207,050 ) Depreciation and amortization $ (101,536 ) $ (762 ) $ (102,298 ) Impairment of long-lived assets and equity investments $ (20,240 ) $ — $ (20,240 ) Equity in net earnings from investments $ 40,058 $ — $ 40,058 Capital expenditures $ 131,377 $ 3,822 $ 135,199 Three Months Ended Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Total ( Thousands of dollars ) Sales to unaffiliated customers $ 361,717 $ 1,905,273 $ 90,401 $ 2,357,391 Intersegment revenues 150,501 133,984 1,676 286,161 Total revenues 512,218 2,039,257 92,077 2,643,552 Cost of sales and fuel (exclusive of depreciation and items shown separately below) (336,456 ) (1,694,161 ) (6,870 ) (2,037,487 ) Operating costs (69,443 ) (79,771 ) (28,373 ) (177,587 ) Equity in net earnings from investments 2,596 13,960 18,599 35,155 Other 922 (29 ) 4,871 5,764 Segment adjusted EBITDA $ 109,837 $ 279,256 $ 80,304 $ 469,397 Depreciation and amortization $ (44,994 ) $ (40,751 ) $ (12,057 ) $ (97,802 ) Capital expenditures $ 99,649 $ 30,533 $ 24,495 $ 154,677 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $299.2 million , of which $253.4 million related to sales within the segment and cost of sales and fuel of $119.6 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $61.0 million and cost of sales and fuel of $7.8 million . Three Months Ended September 30, 2016 Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated Sales to unaffiliated customers $ 2,357,391 $ 516 $ 2,357,907 Intersegment revenues 286,161 (286,161 ) — Total revenues $ 2,643,552 $ (285,645 ) $ 2,357,907 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (2,037,487 ) $ 285,894 $ (1,751,593 ) Operating costs $ (177,587 ) $ (6,564 ) $ (184,151 ) Depreciation and amortization $ (97,802 ) $ (748 ) $ (98,550 ) Equity in net earnings from investments $ 35,155 $ — $ 35,155 Capital expenditures $ 154,677 $ 3,597 $ 158,274 Nine Months Ended Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Total ( Thousands of dollars ) Sales to unaffiliated customers $ 1,286,669 $ 6,788,451 $ 305,019 $ 8,380,139 Intersegment revenues 843,350 455,197 6,086 1,304,633 Total revenues 2,130,019 7,243,648 311,105 9,684,772 Cost of sales and fuel (exclusive of depreciation and items shown separately below) (1,544,263 ) (6,188,501 ) (33,990 ) (7,766,754 ) Operating costs (225,079 ) (256,262 ) (92,468 ) (573,809 ) Equity in net earnings from investments 9,843 44,071 65,071 118,985 Other 3,658 2,501 1,427 7,586 Segment adjusted EBITDA $ 374,178 $ 845,457 $ 251,145 $ 1,470,780 Depreciation and amortization $ (137,843 ) $ (124,471 ) $ (37,906 ) $ (300,220 ) Impairment of long-lived assets and equity investments $ (20,240 ) $ — $ — $ (20,240 ) Total assets $ 5,385,778 $ 8,515,535 $ 2,040,445 $ 15,941,758 Capital expenditures $ 185,713 $ 59,813 $ 70,671 $ 316,197 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $878.8 million , of which $752.5 million related to sales within the segment and cost of sales and fuel of $359.6 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $197.3 million and cost of sales and fuel of $32.9 million . Nine Months Ended September 30, 2017 Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated Sales to unaffiliated customers $ 8,380,139 $ 1,610 $ 8,381,749 Intersegment revenues 1,304,633 (1,304,633 ) — Total revenues $ 9,684,772 $ (1,303,023 ) $ 8,381,749 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (7,766,754 ) $ 1,302,473 $ (6,464,281 ) Operating costs $ (573,809 ) $ (42,968 ) $ (616,777 ) Depreciation and amortization $ (300,220 ) $ (2,346 ) $ (302,566 ) Impairment of long-lived assets and equity investments $ (20,240 ) $ — $ (20,240 ) Equity in net earnings from investments $ 118,985 $ — $ 118,985 Total assets $ 15,941,758 $ 823,083 $ 16,764,841 Capital expenditures $ 316,197 $ 14,234 $ 330,431 Nine Months Ended Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Total ( Thousands of dollars ) Sales to unaffiliated customers $ 971,834 $ 5,030,820 $ 262,276 $ 6,264,930 Intersegment revenues 449,154 367,820 3,843 820,817 Total revenues 1,420,988 5,398,640 266,119 7,085,747 Cost of sales and fuel (exclusive of depreciation and items shown separately below) (902,747 ) (4,376,345 ) (15,914 ) (5,295,006 ) Operating costs (208,353 ) (236,722 ) (85,075 ) (530,150 ) Equity in net earnings from investments 7,987 41,211 51,243 100,441 Other 2,295 (748 ) 6,812 8,359 Segment adjusted EBITDA $ 320,170 $ 826,036 $ 223,185 $ 1,369,391 Depreciation and amortization $ (133,258 ) $ (122,153 ) $ (34,634 ) $ (290,045 ) Total assets $ 5,268,161 $ 8,257,203 $ 1,912,951 $ 15,438,315 Capital expenditures $ 325,820 $ 85,519 $ 71,721 $ 483,060 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $878.5 million , of which $742.6 million related to sales within the segment and cost of sales and fuel of $339.1 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $172.4 million and cost of sales and fuel of $19.1 million . Nine Months Ended September 30, 2016 Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated Sales to unaffiliated customers $ 6,264,930 $ 1,543 $ 6,266,473 Intersegment revenues 820,817 (820,817 ) — Total revenues $ 7,085,747 $ (819,274 ) $ 6,266,473 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (5,295,006 ) $ 820,352 $ (4,474,654 ) Operating costs $ (530,150 ) $ (22,855 ) $ (553,005 ) Depreciation and amortization $ (290,045 ) $ (2,230 ) $ (292,275 ) Equity in net earnings from investments $ 100,441 $ — $ 100,441 Total assets $ 15,438,315 $ 543,720 $ 15,982,035 Capital expenditures $ 483,060 $ 8,468 $ 491,528 Three Months Ended Nine Months Ended September 30, September 30, 2017 2016 2017 2016 Reconciliation of income from continuing operations to total segment adjusted EBITDA ( Thousands of dollars ) Income from continuing operations $ 166,531 $ 194,792 $ 528,707 $ 550,789 Add: Interest expense, net of capitalized interest 126,533 118,240 361,468 355,463 Depreciation and amortization 102,298 98,550 302,566 292,275 Income taxes 97,128 55,012 195,913 157,536 Impairment charges 20,240 — 20,240 — Noncash compensation expense 4,883 3,165 9,790 20,170 Other corporate costs and noncash items (a) 5,783 (362 ) 52,096 (6,842 ) Total segment adjusted EBITDA $ 523,396 $ 469,397 $ 1,470,780 $ 1,369,391 (a) - The nine months ended September 30, 2017, includes our April 2017 $20 million contribution of Series E Preferred Stock to the Foundation and costs related to the Merger Transaction of $29.5 million .

SUPPLEMENTAL CONDENSED CONSOL38

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2017
Condensed Financial Information of Parent Company Only Disclosure [Abstract]
Condensed Consolidating Statements of Income	Condensed Consolidating Statements of Income Three Months Ended September 30, 2017 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 2,322.5 $ — $ 2,322.5 Services — — — 584.3 (0.5 ) 583.8 Total revenues — — — 2,906.8 (0.5 ) 2,906.3 Cost of sales and fuel (exclusive of items shown separately below) — — — 2,229.4 — 2,229.4 Operating expenses 3.9 — 2.6 303.3 (0.5 ) 309.3 Impairment of long-lived assets — — — 16.0 — 16.0 Gain on sale of assets — — — (0.3 ) — (0.3 ) Operating income (3.9 ) — (2.6 ) 358.4 — 351.9 Equity in net earnings from investments 298.0 298.3 300.9 27.6 (884.7 ) 40.1 Impairment of equity investments — — — (4.3 ) — (4.3 ) Other income (expense), net 6.8 86.1 86.1 (4.3 ) (172.2 ) 2.5 Interest expense, net (43.2 ) (86.1 ) (86.1 ) (83.3 ) 172.2 (126.5 ) Income before income taxes 257.7 298.3 298.3 294.1 (884.7 ) — 263.7 Income taxes (91.9 ) — — (5.3 ) — (97.2 ) Net income 165.8 298.3 298.3 288.8 (884.7 ) 166.5 Less: Net income attributable to noncontrolling interests 0.1 — — 0.7 — 0.8 Net income attributable to ONEOK 165.7 298.3 298.3 288.1 (884.7 ) 165.7 Less: Preferred stock dividends 0.2 — — — — 0.2 Net income available to common shareholders $ 165.5 $ 298.3 $ 298.3 $ 288.1 $ (884.7 ) $ 165.5 Three Months Ended September 30, 2016 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 1,840.5 $ — $ 1,840.5 Services — — — 517.9 (0.5 ) 517.4 Total revenues — — — 2,358.4 (0.5 ) 2,357.9 Cost of sales and fuel (exclusive of items shown separately below) — — — 1,751.6 — 1,751.6 Operating expenses 6.7 — — 276.4 (0.5 ) 282.6 Gain on sale of assets — — — (5.7 ) — (5.7 ) Operating income (6.7 ) — — 336.1 — 329.4 Equity in net earnings from investments 273.5 274.3 274.3 17.4 (804.3 ) 35.2 Other income (expense), net 3.4 95.3 95.3 — (190.6 ) 3.4 Interest expense, net (25.7 ) (95.3 ) (95.3 ) (92.5 ) 190.6 (118.2 ) Income before income taxes 244.5 274.3 274.3 261.0 (804.3 ) 249.8 Income taxes (51.4 ) — — (3.6 ) — (55.0 ) Income from continuing operations 193.1 274.3 274.3 257.4 (804.3 ) 194.8 Income (loss) from discontinued operations, net of tax — — — (0.6 ) — (0.6 ) Net income 193.1 274.3 274.3 256.8 (804.3 ) 194.2 Less: Net income attributable to noncontrolling interests 101.0 — — 1.1 — 102.1 Net income attributable to ONEOK $ 92.1 $ 274.3 $ 274.3 $ 255.7 $ (804.3 ) $ 92.1 Nine Months Ended September 30, 2017 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 6,700.3 $ — $ 6,700.3 Services — — — 1,683.0 (1.5 ) 1,681.5 Total revenues — — — 8,383.3 (1.5 ) 8,381.8 Cost of sales and fuel (exclusive of items shown separately below) — — — 6,464.3 — 6,464.3 Operating expenses 34.0 — 8.8 878.0 (1.5 ) 919.3 Impairment of long-lived assets — — — 16.0 — 16.0 Gain on sale of assets — — — (0.9 ) — (0.9 ) Operating income (34.0 ) — (8.8 ) 1,025.9 — 983.1 Equity in net earnings from investments 842.0 845.9 854.7 72.1 (2,495.7 ) 119.0 Impairment of equity investments — — — (4.3 ) — (4.3 ) Other income (expense), net (7.4 ) 272.2 272.2 (4.3 ) (544.4 ) (11.7 ) Interest expense, net (93.5 ) (272.2 ) (272.2 ) (268.0 ) 544.4 (361.5 ) Income before income taxes 707.1 845.9 845.9 821.4 (2,495.7 ) 724.6 Income taxes (180.9 ) — — (15.0 ) — (195.9 ) Net income 526.2 845.9 845.9 806.4 (2,495.7 ) 528.7 Less: Net income attributable to noncontrolling interests 201.4 — — 2.5 — 203.9 Net income attributable to ONEOK 324.8 845.9 845.9 803.9 (2,495.7 ) 324.8 Less: Preferred stock dividends 0.5 — — — — 0.5 Net income available to common shareholders $ 324.3 $ 845.9 $ 845.9 $ 803.9 $ (2,495.7 ) $ 324.3 Nine Months Ended September 30, 2016 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 4,757.3 $ — $ 4,757.3 Services — — — 1,510.7 (1.5 ) 1,509.2 Total revenues — — — 6,268.0 (1.5 ) 6,266.5 Cost of sales and fuel (exclusive of items shown separately below) — — — 4,474.7 — 4,474.7 Operating expenses 23.1 — — 823.6 (1.5 ) 845.2 Gain on sale of assets — — — (9.5 ) — (9.5 ) Operating income (23.1 ) — — 979.2 — 956.1 Equity in net earnings from investments 786.8 789.3 789.3 48.2 (2,313.2 ) 100.4 Other income (expense), net 7.8 284.6 284.6 (0.5 ) (569.2 ) 7.3 Interest expense, net (77.1 ) (284.6 ) (284.6 ) (278.4 ) 569.2 (355.5 ) Income before income taxes 694.4 789.3 789.3 748.5 (2,313.2 ) 708.3 Income taxes (149.8 ) — — (7.7 ) — (157.5 ) Income from continuing operations 544.6 789.3 789.3 740.8 (2,313.2 ) 550.8 Income (loss) from discontinued operations, net of tax — — — (1.8 ) — (1.8 ) Net income 544.6 789.3 789.3 739.0 (2,313.2 ) 549.0 Less: Net income attributable to noncontrolling interests 283.1 — — 4.4 — 287.5 Net income attributable to ONEOK $ 261.5 $ 789.3 $ 789.3 $ 734.6 $ (2,313.2 ) $ 261.5
Condensed Consolidating Statements of Comprehensive Income	Condensed Consolidating Statements of Comprehensive Income Three Months Ended September 30, 2017 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 165.8 $ 298.3 $ 298.3 $ 288.8 $ (884.7 ) $ 166.5 Other comprehensive income (loss), net of tax Unrealized gains (losses) on derivatives, net of tax 18.4 (61.9 ) (42.4 ) (19.5 ) 84.8 (20.6 ) Realized (gains) losses on derivatives in net income, net of tax 0.6 19.8 15.9 8.6 (31.8 ) 13.1 Change in pension and postretirement benefit plan liability, net of tax 2.0 — — — — 2.0 Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax — (0.3 ) (0.3 ) (0.2 ) 0.6 (0.2 ) Total other comprehensive income (loss) 21.0 (42.4 ) (26.8 ) (11.1 ) 53.6 (5.7 ) Comprehensive income 186.8 255.9 271.5 277.7 (831.1 ) 160.8 Less: Comprehensive income attributable to noncontrolling interests — — — 0.7 — 0.7 Comprehensive income attributable to ONEOK $ 186.8 $ 255.9 $ 271.5 $ 277.0 $ (831.1 ) $ 160.1 Three Months Ended September 30, 2016 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 193.1 $ 274.3 $ 274.3 $ 256.8 $ (804.3 ) $ 194.2 Other comprehensive income (loss), net of tax Unrealized gains (losses) on derivatives, net of tax — 8.5 7.6 14.8 (23.7 ) 7.2 Realized (gains) losses on derivatives in net income, net of tax 0.5 3.0 (1.0 ) 1.0 (0.4 ) 3.1 Change in pension and postretirement benefit plan liability, net of tax 1.6 — — — — 1.6 Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax — (0.7 ) (0.7 ) (1.3 ) 2.1 (0.6 ) Total other comprehensive income (loss) 2.1 10.8 5.9 14.5 (22.0 ) 11.3 Comprehensive income 195.2 285.1 280.2 271.3 (826.3 ) 205.5 Less: Comprehensive income attributable to noncontrolling interests 107.4 — — 1.1 — 108.5 Comprehensive income attributable to ONEOK $ 87.8 $ 285.1 $ 280.2 $ 270.2 $ (826.3 ) $ 97.0 Nine Months Ended September 30, 2017 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 526.2 $ 845.9 $ 845.9 $ 806.4 $ (2,495.7 ) $ 528.7 Other comprehensive income (loss), net of tax Unrealized gains (losses) on derivatives, net of tax 18.1 (38.8 ) (6.1 ) 13.3 12.2 (1.3 ) Realized (gains) losses on derivatives in net income, net of tax 1.6 50.7 38.0 26.0 (76.0 ) 40.3 Change in pension and postretirement benefit plan liability, net of tax 6.1 — — — — 6.1 Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax — (1.5 ) (1.5 ) (1.2 ) 3.0 (1.2 ) Total other comprehensive income (loss) 25.8 10.4 30.4 38.1 (60.8 ) 43.9 Comprehensive income 552.0 856.3 876.3 844.5 (2,556.5 ) 572.6 Less: Comprehensive income attributable to noncontrolling interests 232.4 — — 2.5 — 234.9 Comprehensive income attributable to ONEOK $ 319.6 $ 856.3 $ 876.3 $ 842.0 $ (2,556.5 ) $ 337.7 Nine Months Ended September 30, 2016 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Net income $ 544.6 $ 789.3 $ 789.3 $ 739.0 $ (2,313.2 ) $ 549.0 Other comprehensive income (loss), net of tax Unrealized gains (losses) on derivatives, net of tax — (98.6 ) (39.4 ) (123.0 ) 177.4 (83.6 ) Realized (gains) losses on derivatives in net income, net of tax 1.6 (17.8 ) (29.5 ) (43.0 ) 75.2 (13.5 ) Change in pension and postretirement benefit plan liability, net of tax 4.7 — — — — 4.7 Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax — (12.1 ) (12.1 ) (22.3 ) 36.3 (10.2 ) Total other comprehensive income (loss) 6.3 (128.5 ) (81.0 ) (188.3 ) 288.9 (102.6 ) Comprehensive income 550.9 660.8 708.3 550.7 (2,024.3 ) 446.4 Less: Comprehensive income attributable to noncontrolling interests 207.6 — — 4.4 — 212.0 Comprehensive income attributable to ONEOK $ 343.3 $ 660.8 $ 708.3 $ 546.3 $ (2,024.3 ) $ 234.4
Condensed Consolidating Balance Sheets	Condensed Consolidating Balance Sheets September 30, 2017 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total Assets ( Millions of dollars ) Current assets Cash and cash equivalents $ 11.7 $ — $ — $ — $ — $ 11.7 Accounts receivable, net — — — 939.6 — 939.6 Natural gas and natural gas liquids in storage — — — 314.3 — 314.3 Other current assets 10.6 0.3 — 242.4 — 253.3 Total current assets 22.3 0.3 — 1,496.3 — 1,518.9 Property, plant and equipment Property, plant and equipment 139.8 — — 15,224.5 — 15,364.3 Accumulated depreciation and amortization 96.2 — — 2,689.5 — 2,785.7 Net property, plant and equipment 43.6 — — 12,535.0 — 12,578.6 Investments and other assets Investments 5,684.0 3,099.4 7,711.6 809.1 (16,290.4 ) 1,013.7 Intercompany notes receivable 2,831.9 8,605.5 3,993.3 — (15,430.7 ) — Other assets 707.4 0.2 — 1,015.9 (69.9 ) 1,653.6 Total investments and other assets 9,223.3 11,705.1 11,704.9 1,825.0 (31,791.0 ) 2,667.3 Total assets $ 9,289.2 $ 11,705.4 $ 11,704.9 $ 15,856.3 $ (31,791.0 ) $ 16,764.8 Liabilities and equity Current liabilities Current maturities of long-term debt $ — $ 425.0 $ — $ 7.7 $ — $ 432.7 Short-term borrowings 932.3 — — — — 932.3 Accounts payable 6.8 — — 916.0 — 922.8 Other current liabilities 47.8 68.2 — 337.2 — 453.2 Total current liabilities 986.9 493.2 — 1,260.9 — 2,741.0 Intercompany debt — — 8,605.5 6,825.2 (15,430.7 ) — Long-term debt, excluding current maturities 2,726.1 5,335.2 — 30.7 — 8,092.0 Deferred credits and other liabilities 216.7 — — 268.6 (69.9 ) 415.4 Commitments and contingencies Equity Equity excluding noncontrolling interests in consolidated subsidiaries 5,359.5 5,877.0 3,099.4 7,314.0 (16,290.4 ) 5,359.5 Noncontrolling interests in consolidated subsidiaries — — — 156.9 — 156.9 Total equity 5,359.5 5,877.0 3,099.4 7,470.9 (16,290.4 ) 5,516.4 Total liabilities and equity $ 9,289.2 $ 11,705.4 $ 11,704.9 $ 15,856.3 $ (31,791.0 ) $ 16,764.8 December 31, 2016 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total Assets ( Millions of dollars ) Current assets Cash and cash equivalents $ 248.5 $ — $ 0.4 $ — $ — $ 248.9 Accounts receivable, net — — — 872.4 — 872.4 Natural gas and natural gas liquids in storage — — — 140.0 — 140.0 Other current assets 7.2 — — 160.6 — 167.8 Assets of discontinued operations — — — 0.6 — 0.6 Total current assets 255.7 — 0.4 1,173.6 — — 1,429.7 Property, plant and equipment Property, plant and equipment 139.8 — — 14,938.7 — 15,078.5 Accumulated depreciation and amortization 90.4 — — 2,416.7 — 2,507.1 Net property, plant and equipment 49.4 — — 12,522.0 — 12,571.4 Investments and other assets Investments 2,931.9 3,222.1 6,805.4 631.1 (12,631.7 ) 958.8 Intercompany notes receivable 205.2 10,615.0 7,031.3 — (17,851.5 ) — Other assets 103.4 47.5 — 1,028.0 — 1,178.9 Total investments and other assets 3,240.5 13,884.6 13,836.7 1,659.1 (30,483.2 ) 2,137.7 Total assets $ 3,545.6 $ 13,884.6 $ 13,837.1 $ 15,354.7 $ (30,483.2 ) $ 16,138.8 Liabilities and equity Current liabilities Current maturities of long-term debt $ 3.0 $ 400.0 $ — $ 7.7 $ — $ 410.7 Short-term borrowings — 1,110.3 — — — 1,110.3 Accounts payable 13.0 — — 861.7 — 874.7 Other current liabilities 44.7 99.9 — 296.5 — 441.1 Total current liabilities 60.7 1,610.2 — 1,165.9 — 2,836.8 Intercompany debt — — 10,615.0 7,236.5 (17,851.5 ) — Long-term debt, excluding current maturities 1,628.7 6,254.7 — 36.6 — 7,920.0 Deferred credits and other liabilities 1,667.5 — — 285.6 — 1,953.1 Commitments and contingencies Equity Equity excluding noncontrolling interests in consolidated subsidiaries 188.7 6,019.7 3,222.1 6,472.0 (15,713.8 ) 188.7 Noncontrolling interests in consolidated subsidiaries — — — 158.1 3,082.1 3,240.2 Total equity 188.7 6,019.7 3,222.1 6,630.1 (12,631.7 ) 3,428.9 Total liabilities and equity $ 3,545.6 $ 13,884.6 $ 13,837.1 $ 15,354.7 $ (30,483.2 ) $ 16,138.8
Condensed Consolidating Statements of Cash Flows	Condensed Consolidating Statements of Cash Flows Nine Months Ended September 30, 2017 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 620.8 $ 994.3 $ 42.1 $ 1,005.8 $ (1,727.0 ) $ 936.0 Investing activities Capital expenditures (0.5 ) — — (329.9 ) — (330.4 ) Contributions to unconsolidated affiliates — — (83.0 ) (4.7 ) — (87.7 ) Other investing activities — — 11.2 12.3 — 23.5 Cash used in investing activities (0.5 ) — (71.8 ) (322.3 ) — (394.6 ) Financing activities Dividends paid (543.4 ) (999.0 ) (999.0 ) — 1,998.0 (543.4 ) Distributions to noncontrolling interests — — — (4.1 ) (271.0 ) (275.1 ) Intercompany borrowings (advances), net (2,376.9 ) 2,022.2 1,028.3 (673.6 ) — — Borrowing (repayment) of short-term borrowings, net 932.3 (1,110.3 ) — — — (178.0 ) Issuance of long-term debt, net of discounts 1,190.1 — — — — 1,190.1 Repayment of long-term debt (87.1 ) (900.0 ) — (5.8 ) — (992.9 ) Issuance of common stock 45.8 — — — — 45.8 Other (17.9 ) (7.2 ) — — — (25.1 ) Cash provided by (used in) financing activities (857.1 ) (994.3 ) 29.3 — (683.5 ) 1,727.0 (778.6 ) Change in cash and cash equivalents (236.8 ) — (0.4 ) — — (237.2 ) Cash and cash equivalents at beginning of period 248.5 — 0.4 — — 248.9 Cash and cash equivalents at end of period $ 11.7 $ — $ — $ — $ — $ 11.7 Nine Months Ended September 30, 2016 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Operating activities Cash provided by operating activities $ 546.3 $ 998.3 $ 52.3 $ 916.7 $ (1,591.6 ) $ 922.0 Investing activities Capital expenditures (0.1 ) — — (491.4 ) — (491.5 ) Other investing activities — — 30.0 (23.1 ) — 6.9 Cash provided by (used in) investing activities (0.1 ) — 30.0 (514.5 ) — (484.6 ) Financing activities Dividends paid (388.1 ) (999.0 ) (999.0 ) — 1,998.0 (388.1 ) Distributions to noncontrolling interests — — — (6.1 ) (406.4 ) (412.5 ) Intercompany borrowings (advances), net (33.1 ) (493.7 ) 917.1 (390.3 ) — — Borrowing (repayment) of short-term borrowings, net — 147.2 — — — 147.2 Issuance of long-term debt, net of discounts — 1,000.0 — — — 1,000.0 Debt financing costs — (2.8 ) — — — (2.8 ) Repayment of long-term debt (0.3 ) (650.0 ) — (5.8 ) — (656.1 ) Issuance of common stock 14.9 — — — — 14.9 Cash used in financing activities (406.6 ) (998.3 ) (81.9 ) (402.2 ) 1,591.6 (297.4 ) Change in cash and cash equivalents 139.6 — 0.4 — — 140.0 Change in cash and cash equivalents included in discontinued operations (0.2 ) — — — — (0.2 ) Change in cash and cash equivalents included in continuing operations 139.4 — 0.4 — — 139.8 Cash and cash equivalents at beginning of period 92.5 — 5.1 — — 97.6 Cash and cash equivalents at end of period $ 231.9 $ — $ 5.5 $ — $ — $ 237.4

SUMMARY OF SIGNIFICANT ACCOUN39

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Accounting Policies [Abstract]
Impairment of long-lived assets	$ 15,970	$ 0	$ 15,970	$ 0
Equity Method Investment, Other than Temporary Impairment	$ 4,270	$ 0	$ 4,270	$ 0

ONEOK PARTNERS ACQUISITION (Det

ONEOK PARTNERS ACQUISITION (Details) - USD ($) $ in Thousands	6 Months Ended	9 Months Ended		12 Months Ended
	Jun. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Business Acquisition [Line Items]
Business Acquisition, Date of Acquisition Agreement	Jun. 30, 2017
Business Acquisition, Description of Acquired Entity	we completed the Merger Transaction at a fixed exchange ratio of 0.985 of a share of our common stock for each ONEOK Partners common unit that we did not already own. We issued 168.9 million shares of our common stock to third-party common unitholders of ONEOK Partners in exchange for all of the 171.5 million outstanding common units of ONEOK Partners that we previously did not own. No fractional shares were issued in the Merger Transaction, and ONEOK Partners common unitholders instead received cash in lieu of fractional shares. As a result of the completion of the Merger Transaction, common units of ONEOK Partners are no longer publicly traded.
Deferred Tax Assets, Gross, Current	$ 2,100,000
Deferred Tax Asset, Tax Basis	8,800,000
Deferred Tax Asset, Book Basis	$ 3,000,000
Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent	37.00%
General partnership ownership interest	41.20%			41.20%
Common stock		$ 45,849	$ 14,948
Accumulated other comprehensive loss		(40,288)
Noncontrolling interests in consolidated subsidiaries		$ 2,146,462
ONEOK [Member]
Business Acquisition [Line Items]
Common stock	$ 1,700
Paid-in capital	5,228,600
Accumulated other comprehensive loss	(40,300)
Noncontrolling interests in consolidated subsidiaries	(3,043,500)
Deferred income taxes	$ (2,146,500)

FAIR VALUE MEASUREMENTS - Part

FAIR VALUE MEASUREMENTS - Part 1 (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Cash held - offsetting derivative net asset positions under master-netting arrangements	$ 0	$ 0
Cash posted - total	52,800	67,700
Cash posted - offsetting derivative net liability positions under master-netting arrangements	25,400	51,600
Cash posted - remaining in excess of derivative net liability positions included in consolidated Balance Sheets	27,400	16,100
Long-term debt, Fair Value	9,300,000	8,800,000
Long-term debt	8,500,000	8,300,000
Fair Value, Measurements, Recurring [Member]
Derivative assets
Financial contracts	27	951
Interest-rate contracts	45,684	47,457
Total derivative assets	45,711	48,408
Derivative assets netting	(17,839)	(4,760)
Derivative liabilities
Financial contracts	(199)	0
Physical contracts	(4,083)	(3,022)
Interest-rate contracts		(12,795)
Total derivative liabilities	(4,282)	(15,817)
Derivative liabilities netting	43,268	56,319
Fair Value, Measurements, Recurring [Member] | Estimate of Fair Value Measurement [Member]
Derivative assets
Financial contracts	17,866	5,711
Interest-rate contracts	45,684	47,457
Total derivative assets	63,550	53,168
Derivative liabilities
Financial contracts	(43,467)	(56,319)
Physical contracts	(4,083)	(3,022)
Interest-rate contracts		(12,795)
Total derivative liabilities	(47,550)	(72,136)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 1 [Member]
Derivative assets
Financial contracts	1,237	1,147
Interest-rate contracts	0	0
Total derivative assets	1,237	1,147
Derivative liabilities
Financial contracts	(4,415)	(31,458)
Physical contracts	0	0
Interest-rate contracts		0
Total derivative liabilities	(4,415)	(31,458)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative assets
Financial contracts	0	0
Interest-rate contracts	45,684	47,457
Total derivative assets	45,684	47,457
Derivative liabilities
Financial contracts	0	0
Physical contracts	0	0
Interest-rate contracts		(12,795)
Total derivative liabilities	0	(12,795)
Fair Value, Measurements, Recurring [Member] | Fair Value, Inputs, Level 3 [Member]
Derivative assets
Financial contracts	16,629	4,564
Interest-rate contracts	0	0
Total derivative assets	16,629	4,564
Derivative liabilities
Financial contracts	(39,052)	(24,861)
Physical contracts	(4,083)	(3,022)
Interest-rate contracts		0
Total derivative liabilities	$ (43,135)	$ (27,883)

FAIR VALUE MEASUREMENTS - Par42

FAIR VALUE MEASUREMENTS - Part 2 (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Fair Value, Assets And Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Net assets (liabilities) at beginning of period	$ 750	$ (14,021)	$ (23,319)	$ 7,331
Total realized/unrealized gains (losses):
Included in earnings	(675)	920	(417)	492
Included in other comprehensive income (loss)	(26,581)	3,038	(2,770)	(17,886)
Net assets (liabilities) at end of period	(26,506)	(10,063)	(26,506)	(10,063)
Transfers between levels	$ 0	$ 0	$ 0	$ 0

RISK MANAGEMENT AND HEDGING A43

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES Part 1 (Details) - USD ($)	Sep. 30, 2017	Dec. 31, 2016
Derivative, Fair Value [Line Items]
Assets	$ 63,550,000	$ 53,168,000
(Liabilities)	(47,550,000)	(72,136,000)
Derivative, Net Liability Position, Aggregate Fair Value	0
Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	56,962,000	48,822,000
(Liabilities)	(40,398,000)	(67,897,000)
Derivatives not designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	6,588,000	4,346,000
(Liabilities)	(7,152,000)	(4,239,000)
Natural Gas Pipelines [Member]
Derivative, Fair Value [Line Items]
Derivative, Fair Value, Net	0	0
Other Current Assets [Member] | Commodity contracts | Financial contracts | Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	9,180,000	1,155,000
Other Current Assets [Member] | Commodity contracts | Financial contracts | Derivatives not designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	5,862,000	4,346,000
Other Current Assets [Member] | Commodity contracts | Physical contracts | Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	0	0
Other Current Assets [Member] | Interest-rate contracts | Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	252,000	0
Other Current Liabilities [Member] | Commodity contracts | Financial contracts | Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
(Liabilities)	(33,500,000)	(49,938,000)
Other Current Liabilities [Member] | Commodity contracts | Financial contracts | Derivatives not designated as hedging instruments
Derivative, Fair Value [Line Items]
(Liabilities)	(6,444,000)	(4,239,000)
Other Current Liabilities [Member] | Commodity contracts | Physical contracts | Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
(Liabilities)	(3,600,000)	(3,022,000)
Other Current Liabilities [Member] | Interest-rate contracts | Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
(Liabilities)	0	(12,795,000)
Other Assets [Member] | Commodity contracts | Financial contracts | Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	2,098,000	210,000
Other Assets [Member] | Commodity contracts | Financial contracts | Derivatives not designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	726,000	0
Other Assets [Member] | Commodity contracts | Physical contracts | Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	0	0
Other Assets [Member] | Interest-rate contracts | Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	45,432,000	47,457,000
Other Liabilities [Member] | Commodity contracts | Financial contracts | Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
(Liabilities)	(2,815,000)	(2,142,000)
Other Liabilities [Member] | Commodity contracts | Financial contracts | Derivatives not designated as hedging instruments
Derivative, Fair Value [Line Items]
(Liabilities)	(708,000)	0
Other Liabilities [Member] | Commodity contracts | Physical contracts | Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
(Liabilities)	(483,000)	0
Other Liabilities [Member] | Interest-rate contracts | Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
(Liabilities)	$ 0	$ 0

RISK MANAGEMENT AND HEDGING A44

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES, Part 2 (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)MMcfMMBbls	Dec. 31, 2016USD ($)MMcfMMBbls
Derivative [Line Items]
Notional Amount Of Cash Flow Hedge Instruments Settled | $	$ 400,000
Senior Notes, Noncurrent | $	1,200,000
Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Amount of accumulated other comprehensive income (loss) attributable primarily to settled interest-rate swaps. | $	$ (91,000)
Designated as Hedging Instrument [Member] | Futures and swaps | - Natural gas (Bcf) | Fixed price | Purchased/ Payor
Derivative [Line Items]
Notional Amount	0	0
Designated as Hedging Instrument [Member] | Futures and swaps | - Natural gas (Bcf) | Fixed price | Sold/ Receiver
Derivative [Line Items]
Notional Amount	(27,600)	(38,400)
Designated as Hedging Instrument [Member] | Futures and swaps | - Natural gas (Bcf) | Basis | Purchased/ Payor
Derivative [Line Items]
Notional Amount	0	0
Designated as Hedging Instrument [Member] | Futures and swaps | - Natural gas (Bcf) | Basis | Sold/ Receiver
Derivative [Line Items]
Notional Amount	(27,600)	(38,400)
Designated as Hedging Instrument [Member] | Put options | - Natural gas (Bcf) | Fixed price | Purchased/ Payor
Derivative [Line Items]
Notional Amount	9,000	49,500
Designated as Hedging Instrument [Member] | Put options | - Natural gas (Bcf) | Fixed price | Sold/ Receiver
Derivative [Line Items]
Notional Amount	0	0
Designated as Hedging Instrument [Member] | Futures, forwards and swaps | - Crude oil and NGLs (MMBbl) | Fixed price | Purchased/ Payor
Derivative [Line Items]
Notional Amount | MMBbls	2.8	0
Designated as Hedging Instrument [Member] | Futures, forwards and swaps | - Crude oil and NGLs (MMBbl) | Fixed price | Sold/ Receiver
Derivative [Line Items]
Notional Amount | MMBbls	(10.3)	(3.6)
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Purchased/ Payor
Derivative [Line Items]
Derivative, Notional Amount | $	$ 1,750,000	$ 2,150,000
Designated as Hedging Instrument [Member] | Interest Rate Contract [Member] | Sold/ Receiver
Derivative [Line Items]
Derivative, Notional Amount | $	$ 0	$ 0
Not Designated as Hedging Instrument [Member] | Futures and swaps | - Natural gas (Bcf) | Fixed price | Purchased/ Payor
Derivative [Line Items]
Notional Amount	2,700	400
Not Designated as Hedging Instrument [Member] | Futures and swaps | - Natural gas (Bcf) | Fixed price | Sold/ Receiver
Derivative [Line Items]
Notional Amount	0	0
Not Designated as Hedging Instrument [Member] | Futures and swaps | - Natural gas (Bcf) | Basis | Purchased/ Payor
Derivative [Line Items]
Notional Amount	2,700	400
Not Designated as Hedging Instrument [Member] | Futures and swaps | - Natural gas (Bcf) | Basis | Sold/ Receiver
Derivative [Line Items]
Notional Amount	0	0
Not Designated as Hedging Instrument [Member] | Futures, forwards and swaps | - Crude oil and NGLs (MMBbl) | Fixed price | Purchased/ Payor
Derivative [Line Items]
Notional Amount | MMBbls	1.2	0.5
Not Designated as Hedging Instrument [Member] | Futures, forwards and swaps | - Crude oil and NGLs (MMBbl) | Fixed price | Sold/ Receiver
Derivative [Line Items]
Notional Amount | MMBbls	(2.2)	(0.7)
LIBOR Based Interest Payments [Member] | Cash Flow Hedging [Member] | Forward Contracts [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount | $	$ 500,000	$ 1,000,000
Forecasted Debt Issuances [Member] | Cash Flow Hedging [Member] | Forward Contracts [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount | $	1,300,000	$ 1,200,000
Derivative, Notional Amount, New Contracts | $	500,000
ONEOK Partners [Member] | Note Payable from Public Offering Due 2017 [Member]
Derivative [Line Items]
Repayment of Senior Notes | $	$ 400,000

RISK MANAGEMENT AND HEDGING A45

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES Part 3 (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (181,771)		$ (181,771)		$ (154,350)
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net			(14,892)
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(32,837)	$ 8,538	(9,976)	$ (98,613)
Total Gain (Loss) Reclassified from Accumulated Other Comprehensive Income (Loss) into Net Income (Effective Portion)	(20,733)	(3,894)	(53,349)	15,154
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	(19,900)		(19,900)
Price Risk Cash Flow Hedge Unrealized Gain (Loss) to be Reclassified During Next 12 Months	(19,100)		(19,100)
Commodity Cash Flow Hedge Gain (Loss) To Be Reclassified After Next 12 Months Net	(800)		(800)
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	(42,450)	7,580	(6,123)	(39,396)
Commodity Contract [Member] | Commodity sales revenues | 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)	(15,913)	908	(38,028)	29,456
Interest Rate Contract [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Amount of accumulated other comprehensive income (loss) attributable primarily to settled interest-rate swaps.	(91,000)		(91,000)
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	(13,800)		(13,800)
Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net	9,613	958	(3,853)	(59,217)
Interest Rate Contract [Member] | Interest expense | 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)	$ (4,820)	$ (4,802)	$ (15,321)	$ (14,302)

DEBT DEBT (Details)

DEBT DEBT (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2017USD ($)Rate	Dec. 31, 2016USD ($)	Dec. 31, 2015USD ($)
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 9,518,167	$ 9,489,057
Unamortized Portion of Terminated Swaps	18,897	20,186
Unamortized debt issuance costs and discounts	(80,164)	(68,320)
Current maturities	(432,650)	(410,650)
Short-term Debt	(932,250)	(1,110,277)
Long-term debt	8,092,000	7,919,996
Senior Notes, Noncurrent	$ 1,200,000
Indebtedness To Adjusted Ebitda Current	4.9
ONEOK, Inc. Commercial Paper Program [Domain]
Debt Instrument [Line Items]
Maximum Amount Of Commercial Paper	$ 2,500,000
ONEOK Partners Commercial Paper Program [Domain]
Debt Instrument [Line Items]
Maximum Amount Of Commercial Paper	2,400,000
ONEOK Credit Agreement 2017 [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	2,500,000
Line of credit facility sublimit	100,000
Line of Credit Facility Swingline Subfacility	200,000
Line Of Credit Facility Option To Increase Borrowing Capacity	$ 3,500,000
Debt Instrument, Covenant Description	Among other things, these covenants include maintaining a ratio of indebtedness to adjusted EBITDA (EBITDA, as defined in our 2017 Credit Agreement, adjusted for all noncash charges and increased for projected EBITDA from certain lender-approved capital expansion projects) of no more than 5.75 to 1 at September 30,2017 and for the following two quarters; 5.5 to 1 for the subsequent two quarters; and 5.0 to 1 thereafter. Once the covenant decreases to 5.0 to 1, if we consummate one or more acquisitions in which the aggregate purchase 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 is completed and the two following quarters. The 2017 Credit Agreement includes a $100 million sublimit for the issuance of standby letters of credit and a $200 million sublimit for swingline loans. Under the terms of the 2017 Credit Agreement, we may request an increase in the size of the facility to an aggregate of $3.5 billion by either commitments from new lenders or increased commitments from existing lenders. The 2017 Credit Agreement contains provisions for an applicable margin rate and an annual facility fee, both of which adjust with changes in our credit ratings. Based on our current credit ratings, borrowings, if any, will accrue at LIBOR plus 110 basis points, and the annual facility fee is 15 basis points. We have the option to request two one-year extensions, subject to lender approval, which may be used for working capital, capital expenditures, acquisitions and mergers, the issuance of letters of credit and for other general corporate purposes. At September 30, 2017, our ratio of indebtedness to adjusted EBITDA was 4.9 to 1, and we were in compliance with all covenants under the 2017 Credit Agreement.
Partnership Credit Agreement [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Interest Rate Description	borrowings, if any, will accrue at LIBOR plus 110 basis points
Line Of Credit Facility, Annual Facility Fee Description	the annual facility fee is 15 basis points
Senior Notes [Member]
Debt Instrument [Line Items]
Proceeds from Debt, Net of Issuance Costs	$ 1,180,000
Partnership Interest [Member] | Term Loan Agreement [Member]
Debt Instrument [Line Items]
Senior Notes, Noncurrent	1,000,000
Guardian Pipeline [Member] | Notes Payables 1 due 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 38,520	44,257
Weighed Average Interest Rate (in hundredths) | Rate	7.85%
Parent Company
Debt Instrument [Line Items]
Commercial Paper	$ 932,250	0
Short-term Debt, Weighted Average Interest Rate, at Point in Time | Rate	1.93%
Parent Company | Note Payable from Public Offering Due 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 547,397	547,397
Interest Rate (in hundredths) | Rate	4.25%
Parent Company | Note Payable Due 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 500,000	500,000
Interest Rate (in hundredths) | Rate	7.50%
Parent Company | Note Payable Due 2027 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 500,000	0
Interest Rate (in hundredths) | Rate	4.00%
Parent Company | Note Payables 1 due 2028 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 0	87,126
Repayment of Senior Notes	$ 87,000
Interest Rate (in hundredths) | Rate	6.50%
Parent Company | Note Payables 2 due 2028 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 100,000	100,000
Interest Rate (in hundredths) | Rate	6.875%
Parent Company | Notes Payables due 2035 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 400,000	400,000
Interest Rate (in hundredths) | Rate	6.00%
Parent Company | Notes Payables due 2047 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 700,000	0
Interest Rate (in hundredths) | Rate	4.95%
Partnership Interest [Member]
Debt Instrument [Line Items]
Commercial Paper	$ 0	1,110,277
Partnership Interest [Member] | Note Payable from Public Offering Due 2017 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	0	400,000
Repayment of Senior Notes	$ 400,000
Interest Rate (in hundredths) | Rate	2.00%
Partnership Interest [Member] | Note Payable from Public Offering Due 2018 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 425,000	425,000
Interest Rate (in hundredths) | Rate	3.20%
Partnership Interest [Member] | Term Loan Agreement [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 500,000	1,000,000
Repayment of Senior Notes	$ 500,000
Delayed-Draw Unsecured Senior Term Loan		1,000,000
Long-term Debt, Percentage Bearing Variable Interest, Percentage Rate | Rate	2.54%
Partnership Interest [Member] | Notes Payables due 2019 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 500,000	500,000
Interest Rate (in hundredths) | Rate	8.625%
Partnership Interest [Member] | Note Payable from Public Offering Due 2020 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 300,000	300,000
Interest Rate (in hundredths) | Rate	3.80%
Partnership Interest [Member] | Note Payable 2 from Public Offering Due 2022 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 900,000	900,000
Interest Rate (in hundredths) | Rate	3.375%
Partnership Interest [Member] | Note Payable from Public Offering Due 2023 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 425,000	425,000
Interest Rate (in hundredths) | Rate	5.00%
Partnership Interest [Member] | Note Payable from Public Offering Due 2025 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 500,000	500,000
Interest Rate (in hundredths) | Rate	4.90%
Partnership Interest [Member] | Notes Payables due 2036 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 600,000	600,000
Interest Rate (in hundredths) | Rate	6.65%
Partnership Interest [Member] | Notes Payables due 2037 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 600,000	600,000
Interest Rate (in hundredths) | Rate	6.85%
Partnership Interest [Member] | Note Payable from Public Offering Due 2041 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 650,000	650,000
Interest Rate (in hundredths) | Rate	6.125%
Partnership Interest [Member] | Note Payable from Public Offering Due 2043 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 400,000	$ 400,000
Interest Rate (in hundredths) | Rate	6.20%
Partnership Interest [Member] | Note Payable from Public Offering Due 2016 [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross			$ 650,000

EQUITY (Details)

EQUITY (Details) - USD ($)	3 Months Ended					6 Months Ended	9 Months Ended		12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners		20.00%					20.00%
Common Stock, Dividends, Per Share, Cash Paid		$ 0.745	$ 0.615	$ 0.615			$ 1.975	$ 1.845
Common Stock, Dividends, Per Share, Declared		$ 0.745			$ 0.615		$ 1.975	$ 1.845
Noncash Contribution Expense							$ 12,600,000	$ 0
Dividends, Preferred Stock, Cash		$ 400,000					100,000
Preferred Stock, Dividends Per Share, Declared							$ 493,000
Partnership Capital Distributions [Line Items]
General partnership ownership interest						41.20%			41.20%
Number of common units owned by related party									41,300,000
Number Of Class B Units Owned By Related Party									73,000,000
Common Stock, Shares, Issued		415,913,504					415,913,504		245,811,180
Issued Under Equity Distribution Agreement [Member]
Partnership Capital Distributions [Line Items]
Partners Capital Account Units Sold Under Equity Distribution Agreement						0			0
General Partner [Member]
Partnership Capital Distributions [Line Items]
General partnership ownership interest						2.00%
Subsequent Event [Member]
Common Stock, Dividends, Per Share, Declared	$ 0.745
Dividends Payable, Date of Record	Nov. 6, 2017
Dividends Payable, Date to be Paid	Nov. 14, 2017
Preferred Stock, Dividends Per Share, Declared	$ 275,000
Distribution Paid [Member]
Partnership Capital Distributions [Line Items]
Distribution per unit		$ 0			$ 0.79		$ 1.58	$ 2.37
Total distributions paid		$ 0			$ 333,001,000		$ 666,001,000	$ 999,002,000
Distribution Declared [Member]
Partnership Capital Distributions [Line Items]
Distribution Made to Member or Limited Partner, Distribution Date			May 1, 2017	Jan. 30, 2017
Distribution per unit		$ 0.79	$ 0.79	$ 0.79
Oneok Partners [Member]
Partnership Capital Distributions [Line Items]
Common Unit, Issued			171,493,399			171,493,399
Aggregate Amount Of Common Units Available For Issuance And Sale Under The Equity Distribution Agreement						$ 650,000,000
ONEOK [Member]
Partnership Capital Distributions [Line Items]
Common Stock, Shares, Issued			168,920,998			168,920,998
Aggregate Amount Of Common Shares Available For Issuance And Sale Under Equity Distribution Agreement							1,000,000,000
Issued Under Equity Agreement [Member]
Common Stock Sold Under Equity Distribution Agreement	2,100,000	1,200,000
Proceeds from Issuance or Sale of Equity, Settled		$ 30,800,000
Issued Under Equity Agreement [Member] | Subsequent Event [Member]
Proceeds from Sale of Common Stock	$ 119,500,000	64,700,000
General Partner [Member] | Distribution Paid [Member]
Partnership Capital Distributions [Line Items]
General partner distributions		0			6,660,000		13,320,000	19,980,000
Incentive distributions		0			100,538,000		201,076,000	301,614,000
Distributions to general partner		0			107,198,000		214,396,000	321,594,000
ONEOK [Member] | Distribution Paid [Member]
Partnership Capital Distributions [Line Items]
Limited partner distributions to ONEOK		0			90,323,000		180,646,000	270,969,000
Limited Partner [Member] | Distribution Paid [Member]
Partnership Capital Distributions [Line Items]
Limited partner distributions to other unitholders		$ 0			$ 135,480,000		$ 270,959,000	$ 406,439,000
Series E Preferred Stock [Member]
Stock Issued During Period, Shares, New Issues							20,000
Stock Issued During Period, Value, New Issues							$ 20,000,000
Noncash Contribution Expense							$ 20,000,000
Preferred Stock, Dividend Rate, Percentage							5.50%

ACCUMULATED OTHER COMPREHENSI48

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Unrealized gains (losses) on risk management assets/liabilities - January 1			$ (52,155)
Pension and Postretirement Benefit Plan Obligations - January 1			(101,236)
Unrealized gains (losses) on risk-management assets/liabilities of unconsolidated affiliates - January 1			(959)
Accumulated other comprehensive loss - January 1			(154,350)
Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax			(14,892)
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax			8
Other Comprehensive Income (Loss), Amount Attributable to Equity Method Investments, before Reclassification Adjustments, Net of Tax			(588)
Other comprehensive income (loss) before reclassifications			(15,472)
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	$ 13,062	$ 3,083	40,272	$ (13,496)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Other Comprehensive Income Attributable to Equity Method Investments, Net of Tax			99
Other Comprehensive Income (Loss), Reclassification Adjustment included in Net Income, Net of Tax	15,152	2,859	28,339	1,612
Impact of Merger Transaction On Unrealized Gains (Losses) on Risk Management Assets/Liabilities			(40,288)
Impact of Merger Transaction on Pension and Postretirement Benefit Plan Obligations			0
Impact of Merger Transaction on Unrealized Gains (Losses) on Risk Management Assets/Liabilities of Unconsolidated Affiliates			0
Impact of Merger Transaction on AOCI, Total			(40,288)
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Parent			(33,054)
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, after Tax	2,041	1,553	6,122	4,658
Other comprehensive income (loss) on investment in unconsolidated affiliates			(489)
Net current-period other comprehensive income (loss) attributable to ONEOK Partners			(27,421)
Unrealized gains (losses) on risk management assets/liabilities - September 30	(85,209)		(85,209)
Pension and Postretirement Benefit Plan Obligations - September 30	(95,114)		(95,114)
Unrealized gains (losses) on risk-management assets/liabilities of unconsolidated affiliates - September 30	(1,448)		(1,448)
Accumulated other comprehensive loss - September 30	(181,771)		(181,771)
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	7,671	811	13,077	(1,658)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	13,062	1,309	22,126	(3,037)
Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member]
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax	(2,038)	(1,550)	(6,114)	(4,649)
Defined Benefit Plan, Amortization of Gain (Loss)	(3,811)	(2,999)	(11,435)	(8,994)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit)	415	416	1,245	1,246
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, before Tax	(3,396)	(2,583)	(10,190)	(7,748)
Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss), Reclassification Adjustment from AOCI, Tax	1,358	1,033	4,076	3,099
Accumulated Other Comprehensive Income from Investments in Unconsolidated Affiliates Attributable to Parent [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Other Comprehensive Income Attributable to Equity Method Investments, Net of Tax	52	0	99	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Other Comprehensive Income Attributable to Equity Method Investments, Before Tax	(83)	0	(264)	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Other Comprehensive Income Attributable to Equity Method Investments, Tax	31	0	59	0
Sales [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Commodity Contract [Member]
Amounts reclassified from accumulated other comprehensive income (loss)	(15,913)	908	(38,028)	29,456
Interest Expense [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] | Interest Rate Contract [Member]
Amounts reclassified from accumulated other comprehensive income (loss)	(4,820)	(4,802)	(15,321)	(14,302)
Total before tax [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Amounts reclassified from accumulated other comprehensive income (loss)	(20,733)	(3,894)	(53,349)	15,154
Tax Expense [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	7,671	811	13,077	(1,658)
Net of tax [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Amounts Reclassified from Accumulated Other Comprehensive Income (Loss)	13,062	3,083	40,272	(13,496)
Net of tax [Member] | Accumulated Other Comprehensive Income from Investments in Unconsolidated Affiliates Attributable to Parent [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Other Comprehensive Income Attributable to Equity Method Investments, Net of Tax	52	0	205	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Other Comprehensive Income Attributable to Equity Method Investments, Net of Tax, Portion Attributable to Noncont Interests	0	0	(106)	0
Net income attributable to noncontrolling interest [Member] | Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member]
Other Comprehensive Income (Loss), Derivatives Qualifying as Hedges, Net of Tax, Portion Attributable to Noncontrolling Interest	$ 0	$ (1,774)	$ (18,146)	$ 10,459

EARNINGS PER SHARE EARNINGS P49

EARNINGS PER SHARE EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Basic EPS from Continuing Operations [Abstract]
Income from continuing operations attributable to ONEOK available for common stock	$ 165,466	$ 92,720	$ 324,303	$ 263,289
Shares	380,907	211,309	268,108	211,038
Basic (in dollars per share)	$ 0.43	$ 0.44	$ 1.21	$ 1.25
Diluted EPS from Continuing Operations [Abstract]
Effect of options and other dilutive securities	$ 0	$ 0	$ 0	$ 0
Effect of options and other dilutive securities, number of shares, shares	2,512	1,561	2,241	1,085
Income from continuing operations attributable to ONEOK available for common stock and common stock equivalents	$ 165,466	$ 92,720	$ 324,303	$ 263,289
Shares	383,419	212,870	270,349	212,123
Diluted (in dollars per share)	$ 0.43	$ 0.44	$ 1.20	$ 1.24

EMPLOYEE BENEFIT PLANS EMPLOY50

EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pension Benefits
Components of net periodic benefit cost
Service cost	$ 1,721	$ 1,622	$ 5,165	$ 4,866
Interest cost	4,655	4,946	13,965	14,840
Expected return on plan assets	(5,336)	(5,077)	(16,008)	(15,231)
Amortization of net loss	3,392	2,737	10,176	8,210
Net periodic benefit cost	4,432	4,228	13,298	12,685
Postretirement Benefits
Components of net periodic benefit cost
Service cost	165	149	495	447
Interest cost	565	601	1,695	1,803
Expected return on plan assets	(564)	(531)	(1,692)	(1,593)
Amortization of prior service credit	(415)	(416)	(1,245)	(1,246)
Amortization of net loss	419	262	1,259	784
Net periodic benefit cost	$ 170	$ 65	$ 512	$ 195

UNCONSOLIDATED AFFILIATES (Deta

UNCONSOLIDATED AFFILIATES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Schedule of Equity Method Investments [Line Items]
Equity in net earnings from investments	$ 40,058	$ 35,155	$ 118,985	$ 100,441
Impairment of long-lived assets	15,970	0	15,970	0
Impairment of equity investments	4,270	0	4,270	0
Accounts Payable, Related Parties, Current	13,100		13,100		$ 11,100
Payments to Acquire Equity Method Investments			83,000
Income Statement [Abstract]
Operating revenues	163,627	143,967	475,510	423,170
Operating expenses	69,740	66,490	206,141	191,863
Net income	87,330	72,672	260,533	214,129
Distributions paid to us	49,414	40,822	146,094	149,399
Unconsolidated Affiliates [Member]
Schedule of Equity Method Investments [Line Items]
Related Party Transaction, Expenses from Transactions with Related Parties	39,900	36,400	116,000	105,300
Northern Border Pipeline [Member]
Schedule of Equity Method Investments [Line Items]
Equity in net earnings from investments	16,440	17,854	50,879	52,251
Overland Pass Pipeline Company [Member]
Schedule of Equity Method Investments [Line Items]
Equity in net earnings from investments	15,793	13,886	44,243	40,798
Other Unconsolidated Affiliates [Member]
Schedule of Equity Method Investments [Line Items]
Equity in net earnings from investments	$ 7,825	$ 3,415	$ 23,863	$ 7,392

SEGMENTS (Details)

SEGMENTS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Segment Reporting Information [Line Items]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 166,531	$ 194,216	$ 528,707	$ 549,034
Segment disclosure [Abstract]
Segment Reporting, Disclosure of Major Customers	For the three months ended September 30, 2017, we had no single customer from which we received 10 percent or more of our consolidated revenues.	For the three months ended September 30, 2016, we had no single customer from which we received 10 percent or more of our consolidated revenues.	For the nine months ended September 30, 2017, we had no single customer from which we received 10 percent or more of our consolidated revenues.	For the nine months ended September 30, 2016, we had no single customer from which we received 10 percent or more of our consolidated revenues.
Revenues	$ 2,906,366	$ 2,357,907	$ 8,381,749	$ 6,266,473
Cost of sales and fuel (exclusive of depreciation and items shown separately below)	(2,229,416)	(1,751,593)	(6,464,281)	(4,474,654)
Operating costs	(207,050)	(184,151)	(616,777)	(553,005)
Equity in net earnings from investments	40,058	35,155	118,985	100,441
Depreciation and amortization	102,298	98,550	302,566	292,275
Total assets	16,764,841	15,982,035	16,764,841	15,982,035	$ 16,138,751
Capital expenditures	135,199	158,274	330,431	491,528
Income from continuing operations	166,531	194,792	528,707	550,789
Interest expense, net of capitalized interest	126,533	118,240	361,468	355,463
Income taxes	97,128	55,012	195,913	157,536
Impairment Charges	20,240	0	20,240	0
Noncash compensation expense	4,883	3,165	9,790	20,170
Other corporate costs and noncash items	5,783	(362)	52,096	(6,842)
Noncash Contribution Expense			12,600	0
Business Combination, Acquisition Related Costs			29,500
Natural Gas Gathering and Processing [Member]
Segment disclosure [Abstract]
Revenues	782,928	512,218	2,130,019	1,420,988
Cost of sales and fuel (exclusive of depreciation and items shown separately below)	(566,988)	(336,456)	(1,544,263)	(902,747)
Operating costs	(80,197)	(69,443)	(225,079)	(208,353)
Equity in net earnings from investments	3,433	2,596	9,843	7,987
Other	2,774	922	3,658	2,295
Segment adjusted EBITDA	141,950	109,837	374,178	320,170
Depreciation and amortization	46,842	44,994	137,843	133,258
Total assets	5,385,778	5,268,161	5,385,778	5,268,161
Capital expenditures	85,542	99,649	185,713	325,820
Impairment Charges	20,240		20,240
Natural Gas Liquids [Member]
Segment disclosure [Abstract]
Revenues	2,501,979	2,039,257	7,243,648	5,398,640
Cost of sales and fuel (exclusive of depreciation and items shown separately below)	(2,136,207)	(1,694,161)	(6,188,501)	(4,376,345)
Operating costs	(90,234)	(79,771)	(256,262)	(236,722)
Equity in net earnings from investments	15,287	13,960	44,071	41,211
Other	3,094	(29)	2,501	(748)
Segment adjusted EBITDA	293,919	279,256	845,457	826,036
Depreciation and amortization	41,929	40,751	124,471	122,153
Total assets	8,515,535	8,257,203	8,515,535	8,257,203
Capital expenditures	27,024	30,533	59,813	85,519
Impairment Charges	0		0
Natural Gas Liquids [Member] | Natural Gas Liquids Regulated [Member]
Segment disclosure [Abstract]
Revenues	293,100	299,200	878,800	878,500
Cost of sales and fuel (exclusive of depreciation and items shown separately below)	(124,200)	(119,600)	(359,600)	(339,100)
Natural Gas Pipelines [Member]
Segment disclosure [Abstract]
Revenues	106,438	92,077	311,105	266,119
Cost of sales and fuel (exclusive of depreciation and items shown separately below)	(10,614)	(6,870)	(33,990)	(15,914)
Operating costs	(29,838)	(28,373)	(92,468)	(85,075)
Equity in net earnings from investments	21,338	18,599	65,071	51,243
Other	203	4,871	1,427	6,812
Segment adjusted EBITDA	87,527	80,304	251,145	223,185
Depreciation and amortization	12,765	12,057	37,906	34,634
Total assets	2,040,445	1,912,951	2,040,445	1,912,951
Capital expenditures	18,811	24,495	70,671	71,721
Impairment Charges	0		0
Natural Gas Pipelines [Member] | Natural Gas Pipelines Regulated [Member]
Segment disclosure [Abstract]
Revenues	65,600	61,000	197,300	172,400
Cost of sales and fuel (exclusive of depreciation and items shown separately below)	(10,500)	(7,800)	(32,900)	(19,100)
Total Segments [Member]
Segment disclosure [Abstract]
Revenues	3,391,345	2,643,552	9,684,772	7,085,747
Cost of sales and fuel (exclusive of depreciation and items shown separately below)	(2,713,809)	(2,037,487)	(7,766,754)	(5,295,006)
Operating costs	(200,269)	(177,587)	(573,809)	(530,150)
Equity in net earnings from investments	40,058	35,155	118,985	100,441
Other	6,071	5,764	7,586	8,359
Segment adjusted EBITDA	523,396	469,397	1,470,780	1,369,391
Depreciation and amortization	101,536	97,802	300,220	290,045
Total assets	15,941,758	15,438,315	15,941,758	15,438,315
Capital expenditures	131,377	154,677	316,197	483,060
Impairment Charges	20,240		20,240
Other and Eliminations
Segment disclosure [Abstract]
Revenues	(484,979)	(285,645)	(1,303,023)	(819,274)
Cost of sales and fuel (exclusive of depreciation and items shown separately below)	484,393	285,894	1,302,473	820,352
Operating costs	(6,781)	(6,564)	(42,968)	(22,855)
Equity in net earnings from investments	0	0	0	0
Depreciation and amortization	762	748	2,346	2,230
Total assets	823,083	543,720	823,083	543,720
Capital expenditures	3,822	3,597	14,234	8,468
Impairment Charges	0		0
Unaffiliated entity [Member]
Segment disclosure [Abstract]
Revenues	2,906,366	2,357,907	8,381,749	6,266,473
Unaffiliated entity [Member] | Natural Gas Gathering and Processing [Member]
Segment disclosure [Abstract]
Revenues	453,432	361,717	1,286,669	971,834
Unaffiliated entity [Member] | Natural Gas Liquids [Member]
Segment disclosure [Abstract]
Revenues	2,348,052	1,905,273	6,788,451	5,030,820
Unaffiliated entity [Member] | Natural Gas Pipelines [Member]
Segment disclosure [Abstract]
Revenues	104,340	90,401	305,019	262,276
Unaffiliated entity [Member] | Total Segments [Member]
Segment disclosure [Abstract]
Revenues	2,905,824	2,357,391	8,380,139	6,264,930
Unaffiliated entity [Member] | Other and Eliminations
Segment disclosure [Abstract]
Revenues	542	516	1,610	1,543
Operating Segments [Member]
Segment disclosure [Abstract]
Revenues	0	0	0	0
Operating Segments [Member] | Natural Gas Gathering and Processing [Member]
Segment disclosure [Abstract]
Revenues	329,496	150,501	843,350	449,154
Operating Segments [Member] | Natural Gas Liquids [Member]
Segment disclosure [Abstract]
Revenues	153,927	133,984	455,197	367,820
Operating Segments [Member] | Natural Gas Liquids [Member] | Natural Gas Liquids Regulated [Member]
Segment disclosure [Abstract]
Revenues	250,200	253,400	752,500	742,600
Operating Segments [Member] | Natural Gas Pipelines [Member]
Segment disclosure [Abstract]
Revenues	2,098	1,676	6,086	3,843
Operating Segments [Member] | Total Segments [Member]
Segment disclosure [Abstract]
Revenues	485,521	286,161	1,304,633	820,817
Operating Segments [Member] | Other and Eliminations
Segment disclosure [Abstract]
Revenues	$ (485,521)	$ (286,161)	(1,304,633)	$ (820,817)
Series E Preferred Stock [Member]
Segment disclosure [Abstract]
Noncash Contribution Expense			$ 20,000

SUPPLEMENTAL CONDENSED CONSOL53

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION, Income Statement (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Condensed Financial Statements, Captions [Line Items]
Commodity sales	$ 2,322,534	$ 1,840,523	$ 6,700,260	$ 4,757,306
Services	583,832	517,384	1,681,489	1,509,167
Total revenues	2,906,366	2,357,907	8,381,749	6,266,473
Cost of sales and fuel (exclusive of items shown separately below)	2,229,416	1,751,593	6,464,281	4,474,654
Impairment of long-lived assets	15,970	0	15,970	0
Gain on sale of assets	(274)	(5,744)	(904)	(9,537)
Operating income	351,906	329,357	983,059	956,076
Equity in net earnings from investments	40,058	35,155	118,985	100,441
Impairment of equity investments	(4,270)	0	(4,270)	0
Interest expense, net	(126,533)	(118,240)	(361,468)	(355,463)
Income before income taxes	263,659	249,804	724,620	708,325
Income taxes	(97,128)	(55,012)	(195,913)	(157,536)
Income from continuing operations	166,531	194,792	528,707	550,789
Income (loss) from discontinued operations, net of tax	0	576	0	1,755
Net income	166,531	194,216	528,707	549,034
Less: Net income attributable to noncontrolling interests	789	102,072	203,911	287,500
Net income attributable to ONEOK	165,742	92,144	324,796	261,534
Less: Preferred stock dividends	276	0	493	0
Net income available to common shareholders	$ 165,466	92,144	$ 324,303	261,534
Northern Border Pipeline [Member]
Condensed Financial Statements, Captions [Line Items]
Equity Method Investment, Ownership Percentage	50.00%		50.00%
Equity in net earnings from investments	$ 16,440	17,854	$ 50,879	52,251
Reportable Legal Entities | Parent Issuer & Guarantor
Condensed Financial Statements, Captions [Line Items]
Commodity sales	0	0	0	0
Services	0	0	0	0
Total revenues	0	0	0	0
Cost of sales and fuel (exclusive of items shown separately below)	0	0	0	0
Operating expenses	3,900	6,700	34,000	23,100
Impairment of long-lived assets	0		0
Gain on sale of assets	0	0	0	0
Operating income	(3,900)	(6,700)	(34,000)	(23,100)
Equity in net earnings from investments	298,000	273,500	842,000	786,800
Impairment of equity investments	0		0
Other income (expense), net	6,800	3,400	(7,400)	7,800
Interest expense, net	(43,200)	(25,700)	(93,500)	(77,100)
Income before income taxes	257,700	244,500	707,100	694,400
Income taxes	(91,900)	(51,400)	(180,900)	(149,800)
Income from continuing operations		193,100		544,600
Income (loss) from discontinued operations, net of tax		0		0
Net income	165,800	193,100	526,200	544,600
Less: Net income attributable to noncontrolling interests	100	101,000	201,400	283,100
Net income attributable to ONEOK	165,700	92,100	324,800	261,500
Less: Preferred stock dividends	200		500
Net income available to common shareholders	165,500		324,300
Reportable Legal Entities | Subsidiary Issuer & Guarantor
Condensed Financial Statements, Captions [Line Items]
Commodity sales	0	0	0	0
Services	0	0	0	0
Total revenues	0	0	0	0
Cost of sales and fuel (exclusive of items shown separately below)	0	0	0	0
Operating expenses	0	0	0	0
Impairment of long-lived assets	0		0
Gain on sale of assets	0	0	0	0
Operating income	0	0	0	0
Equity in net earnings from investments	298,300	274,300	845,900	789,300
Impairment of equity investments	0		0
Other income (expense), net	86,100	95,300	272,200	284,600
Interest expense, net	(86,100)	(95,300)	(272,200)	(284,600)
Income before income taxes	298,300	274,300	845,900	789,300
Income taxes	0	0	0	0
Income from continuing operations		274,300		789,300
Income (loss) from discontinued operations, net of tax		0		0
Net income	298,300	274,300	845,900	789,300
Less: Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to ONEOK	298,300	274,300	845,900	789,300
Less: Preferred stock dividends	0		0
Net income available to common shareholders	298,300		845,900
Reportable Legal Entities | Guarantor Subsidiary
Condensed Financial Statements, Captions [Line Items]
Commodity sales	0	0	0	0
Services	0	0	0	0
Total revenues	0	0	0	0
Cost of sales and fuel (exclusive of items shown separately below)	0	0	0	0
Operating expenses	2,600	0	8,800	0
Impairment of long-lived assets	0		0
Gain on sale of assets	0	0	0	0
Operating income	(2,600)	0	(8,800)	0
Equity in net earnings from investments	300,900	274,300	854,700	789,300
Impairment of equity investments	0		0
Other income (expense), net	86,100	95,300	272,200	284,600
Interest expense, net	(86,100)	(95,300)	(272,200)	(284,600)
Income before income taxes	298,300	274,300	845,900	789,300
Income taxes	0	0	0	0
Income from continuing operations		274,300		789,300
Income (loss) from discontinued operations, net of tax		0		0
Net income	298,300	274,300	845,900	789,300
Less: Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to ONEOK	298,300	274,300	845,900	789,300
Less: Preferred stock dividends	0		0
Net income available to common shareholders	298,300		845,900
Reportable Legal Entities | Combined Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Commodity sales	2,322,500	1,840,500	6,700,300	4,757,300
Services	584,300	517,900	1,683,000	1,510,700
Total revenues	2,906,800	2,358,400	8,383,300	6,268,000
Cost of sales and fuel (exclusive of items shown separately below)	2,229,400	1,751,600	6,464,300	4,474,700
Operating expenses	303,300	276,400	878,000	823,600
Impairment of long-lived assets	16,000		16,000
Gain on sale of assets	(300)	(5,700)	(900)	(9,500)
Operating income	358,400	336,100	1,025,900	979,200
Equity in net earnings from investments	27,600	17,400	72,100	48,200
Impairment of equity investments	(4,300)		(4,300)
Other income (expense), net	(4,300)	0	(4,300)	(500)
Interest expense, net	(83,300)	(92,500)	(268,000)	(278,400)
Income before income taxes	294,100	261,000	821,400	748,500
Income taxes	(5,300)	(3,600)	(15,000)	(7,700)
Income from continuing operations		257,400		740,800
Income (loss) from discontinued operations, net of tax		(600)		(1,800)
Net income	288,800	256,800	806,400	739,000
Less: Net income attributable to noncontrolling interests	700	1,100	2,500	4,400
Net income attributable to ONEOK	288,100	255,700	803,900	734,600
Less: Preferred stock dividends	0		0
Net income available to common shareholders	288,100		803,900
Reportable Legal Entities | Total
Condensed Financial Statements, Captions [Line Items]
Commodity sales	2,322,500	1,840,500	6,700,300	4,757,300
Services	583,800	517,400	1,681,500	1,509,200
Total revenues	2,906,300	2,357,900	8,381,800	6,266,500
Cost of sales and fuel (exclusive of items shown separately below)	2,229,400	1,751,600	6,464,300	4,474,700
Operating expenses	309,300	282,600	919,300	845,200
Impairment of long-lived assets	16,000		16,000
Gain on sale of assets	(300)	(5,700)	(900)	(9,500)
Operating income	351,900	329,400	983,100	956,100
Equity in net earnings from investments	40,100	35,200	119,000	100,400
Impairment of equity investments	(4,300)		(4,300)
Other income (expense), net	2,500	3,400	(11,700)	7,300
Interest expense, net	(126,500)	(118,200)	(361,500)	(355,500)
Income before income taxes	263,700	249,800	724,600	708,300
Income taxes	(97,200)	(55,000)	(195,900)	(157,500)
Income from continuing operations		194,800		550,800
Income (loss) from discontinued operations, net of tax		(600)		(1,800)
Net income	166,500	194,200	528,700	549,000
Less: Net income attributable to noncontrolling interests	800	102,100	203,900	287,500
Net income attributable to ONEOK	165,700	92,100	324,800	261,500
Less: Preferred stock dividends	200		500
Net income available to common shareholders	165,500		324,300
Consolidating Entries
Condensed Financial Statements, Captions [Line Items]
Commodity sales	0	0	0	0
Services	(500)	(500)	(1,500)	(1,500)
Total revenues	(500)	(500)	(1,500)	(1,500)
Cost of sales and fuel (exclusive of items shown separately below)	0	0	0	0
Operating expenses	(500)	(500)	(1,500)	(1,500)
Impairment of long-lived assets	0		0
Gain on sale of assets	0	0	0	0
Operating income	0	0	0	0
Equity in net earnings from investments	(884,700)	(804,300)	(2,495,700)	(2,313,200)
Impairment of equity investments	0		0
Other income (expense), net	(172,200)	(190,600)	(544,400)	(569,200)
Interest expense, net	172,200	190,600	544,400	569,200
Income before income taxes	(884,700)	(804,300)	(2,495,700)	(2,313,200)
Income taxes	0	0	0	0
Income from continuing operations		(804,300)		(2,313,200)
Income (loss) from discontinued operations, net of tax		0		0
Net income	(884,700)	(804,300)	(2,495,700)	(2,313,200)
Less: Net income attributable to noncontrolling interests	0	0	0	0
Net income attributable to ONEOK	(884,700)	$ (804,300)	(2,495,700)	$ (2,313,200)
Less: Preferred stock dividends	0		0
Net income available to common shareholders	$ (884,700)		$ (2,495,700)

SUPPLEMENTAL CONDENSED CONSOL54

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION, Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Condensed Financial Statements, Captions [Line Items]
Net income	$ 166,531	$ 194,216	$ 528,707	$ 549,034
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on derivatives, net of tax	(20,620)	7,237	(1,287)	(83,580)
Realized (gains) losses on derivatives in net income, net of tax	(13,062)	(3,083)	(40,272)	13,496
Change in pension and postretirement benefit plan liability, net of tax	(2,041)	(1,553)	(6,122)	(4,658)
Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax	(169)	(600)	(1,214)	(10,231)
Total other comprehensive income (loss)	(5,686)	11,273	43,893	(102,649)
Comprehensive income	160,845	205,489	572,600	446,385
Less: Comprehensive income attributable to noncontrolling interests	789	108,450	234,937	211,960
Comprehensive income attributable to ONEOK	160,056	97,039	337,663	234,425
Reportable Legal Entities | Parent Issuer & Guarantor
Condensed Financial Statements, Captions [Line Items]
Net income	165,800	193,100	526,200	544,600
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on derivatives, net of tax	18,400	0	18,100	0
Realized (gains) losses on derivatives in net income, net of tax	600	500	1,600	1,600
Change in pension and postretirement benefit plan liability, net of tax	2,000	1,600	6,100	4,700
Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax	0	0	0	0
Total other comprehensive income (loss)	21,000	2,100	25,800	6,300
Comprehensive income	186,800	195,200	552,000	550,900
Less: Comprehensive income attributable to noncontrolling interests	0	107,400	232,400	207,600
Comprehensive income attributable to ONEOK	186,800	87,800	319,600	343,300
Reportable Legal Entities | Subsidiary Issuer & Guarantor
Condensed Financial Statements, Captions [Line Items]
Net income	298,300	274,300	845,900	789,300
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on derivatives, net of tax	(61,900)	8,500	(38,800)	(98,600)
Realized (gains) losses on derivatives in net income, net of tax	19,800	3,000	50,700	(17,800)
Change in pension and postretirement benefit plan liability, net of tax	0	0	0	0
Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax	(300)	(700)	(1,500)	(12,100)
Total other comprehensive income (loss)	(42,400)	10,800	10,400	(128,500)
Comprehensive income	255,900	285,100	856,300	660,800
Less: Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to ONEOK	255,900	285,100	856,300	660,800
Reportable Legal Entities | Guarantor Subsidiary
Condensed Financial Statements, Captions [Line Items]
Net income	298,300	274,300	845,900	789,300
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on derivatives, net of tax	(42,400)	7,600	(6,100)	(39,400)
Realized (gains) losses on derivatives in net income, net of tax	15,900	(1,000)	38,000	(29,500)
Change in pension and postretirement benefit plan liability, net of tax	0	0	0	0
Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax	(300)	(700)	(1,500)	(12,100)
Total other comprehensive income (loss)	(26,800)	5,900	30,400	(81,000)
Comprehensive income	271,500	280,200	876,300	708,300
Less: Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to ONEOK	271,500	280,200	876,300	708,300
Reportable Legal Entities | Combined Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Net income	288,800	256,800	806,400	739,000
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on derivatives, net of tax	(19,500)	14,800	13,300	(123,000)
Realized (gains) losses on derivatives in net income, net of tax	8,600	1,000	26,000	(43,000)
Change in pension and postretirement benefit plan liability, net of tax	0	0	0	0
Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax	(200)	(1,300)	(1,200)	(22,300)
Total other comprehensive income (loss)	(11,100)	14,500	38,100	(188,300)
Comprehensive income	277,700	271,300	844,500	550,700
Less: Comprehensive income attributable to noncontrolling interests	700	1,100	2,500	4,400
Comprehensive income attributable to ONEOK	277,000	270,200	842,000	546,300
Reportable Legal Entities | Total
Condensed Financial Statements, Captions [Line Items]
Net income	166,500	194,200	528,700	549,000
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on derivatives, net of tax	(20,600)	7,200	(1,300)	(83,600)
Realized (gains) losses on derivatives in net income, net of tax	13,100	3,100	40,300	(13,500)
Change in pension and postretirement benefit plan liability, net of tax	2,000	1,600	6,100	4,700
Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax	(200)	(600)	(1,200)	(10,200)
Total other comprehensive income (loss)	(5,700)	11,300	43,900	(102,600)
Comprehensive income	160,800	205,500	572,600	446,400
Less: Comprehensive income attributable to noncontrolling interests	700	108,500	234,900	212,000
Comprehensive income attributable to ONEOK	160,100	97,000	337,700	234,400
Consolidating Entries
Condensed Financial Statements, Captions [Line Items]
Net income	(884,700)	(804,300)	(2,495,700)	(2,313,200)
Other comprehensive income (loss), net of tax
Unrealized gains (losses) on derivatives, net of tax	84,800	(23,700)	12,200	177,400
Realized (gains) losses on derivatives in net income, net of tax	(31,800)	(400)	(76,000)	75,200
Change in pension and postretirement benefit plan liability, net of tax	0	0	0	0
Other comprehensive income (loss) on investments in unconsolidated affiliates, net of tax	600	2,100	3,000	36,300
Total other comprehensive income (loss)	53,600	(22,000)	(60,800)	288,900
Comprehensive income	(831,100)	(826,300)	(2,556,500)	(2,024,300)
Less: Comprehensive income attributable to noncontrolling interests	0	0	0	0
Comprehensive income attributable to ONEOK	$ (831,100)	$ (826,300)	$ (2,556,500)	$ (2,024,300)

SUPPLEMENTAL CONDENSED CONSOL55

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION, Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Current assets
Cash and cash equivalents	$ 11,676	$ 248,875	$ 237,410	$ 97,619
Accounts receivable, net	939,595	872,430
Natural gas and natural gas liquids in storage	314,266	140,034
Materials and supplies	77,366	60,912
Other current assets	64,196	45,986
Asset of discontinued operations	0	551
Total current assets	1,518,865	1,429,684
Property, plant and equipment
Property, plant and equipment	15,364,289	15,078,497
Accumulated depreciation and amortization	2,785,682	2,507,094
Net property, plant and equipment	12,578,607	12,571,403
Investments and other assets
Investments	1,013,702	958,807
Goodwill and intangible assets	996,435	1,005,359
Other assets	182,265	162,998
Asset of discontinued operations	0	10,500
Total investments and other assets	2,667,369	2,137,664
Total assets	16,764,841	16,138,751	15,982,035
Current liabilities
Current maturities of long-term debt	432,650	410,650
Short-term borrowings	932,250	1,110,277
Accounts payable	922,820	874,731
Commodity imbalances	189,512	142,646
Accrued interest	97,023	112,514
Other current liabilities	166,825	166,042
Liabilities of discontinued operations	0	19,841
Total current liabilities	2,741,080	2,836,701
Long-term debt, excluding current maturities	8,092,000	7,919,996
Deferred credits and other liabilities	415,378	1,953,139
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	5,359,495	188,745
Noncontrolling interests in consolidated subsidiaries	156,888	3,240,170
Total equity	5,516,383	3,428,915	3,440,214	3,766,336
Total liabilities and equity	16,764,841	16,138,751
Reportable Legal Entities | Parent Issuer & Guarantor
Current assets
Cash and cash equivalents	11,700	248,500	231,900	92,500
Accounts receivable, net	0	0
Natural gas and natural gas liquids in storage	0	0
Other current assets	10,600	7,200
Asset of discontinued operations		0
Total current assets	22,300	255,700
Property, plant and equipment
Property, plant and equipment	139,800	139,800
Accumulated depreciation and amortization	96,200	90,400
Net property, plant and equipment	43,600	49,400
Investments and other assets
Investments	5,684,000	2,931,900
Intercompany notes receivable	2,831,900	205,200
Other assets	707,400	103,400
Total investments and other assets	9,223,300	3,240,500
Total assets	9,289,200	3,545,600
Current liabilities
Current maturities of long-term debt	0	3,000
Short-term borrowings	932,300	0
Accounts payable	6,800	13,000
Other current liabilities	47,800	44,700
Total current liabilities	986,900	60,700
Intercompany debt	0	0
Long-term debt, excluding current maturities	2,726,100	1,628,700
Deferred credits and other liabilities	216,700	1,667,500
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	5,359,500	188,700
Noncontrolling interests in consolidated subsidiaries	0	0
Total equity	5,359,500	188,700
Total liabilities and equity	9,289,200	3,545,600
Reportable Legal Entities | Subsidiary Issuer & Guarantor
Current assets
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	0	0
Natural gas and natural gas liquids in storage	0	0
Other current assets	300	0
Asset of discontinued operations		0
Total current assets	300	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
Investments	3,099,400	3,222,100
Intercompany notes receivable	8,605,500	10,615,000
Other assets	200	47,500
Total investments and other assets	11,705,100	13,884,600
Total assets	11,705,400	13,884,600
Current liabilities
Current maturities of long-term debt	425,000	400,000
Short-term borrowings	0	1,110,300
Accounts payable	0	0
Other current liabilities	68,200	99,900
Total current liabilities	493,200	1,610,200
Intercompany debt	0	0
Long-term debt, excluding current maturities	5,335,200	6,254,700
Deferred credits and other liabilities	0	0
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	5,877,000	6,019,700
Noncontrolling interests in consolidated subsidiaries	0	0
Total equity	5,877,000	6,019,700
Total liabilities and equity	11,705,400	13,884,600
Reportable Legal Entities | Guarantor Subsidiary
Current assets
Cash and cash equivalents	0	400	5,500	5,100
Accounts receivable, net	0	0
Natural gas and natural gas liquids in storage	0	0
Other current assets	0	0
Asset of discontinued operations		0
Total current assets	0	400
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
Investments	7,711,600	6,805,400
Intercompany notes receivable	3,993,300	7,031,300
Other assets	0	0
Total investments and other assets	11,704,900	13,836,700
Total assets	11,704,900	13,837,100
Current liabilities
Current maturities of long-term debt	0	0
Short-term borrowings	0	0
Accounts payable	0	0
Other current liabilities	0	0
Total current liabilities	0	0
Intercompany debt	8,605,500	10,615,000
Long-term debt, excluding current maturities	0	0
Deferred credits and other liabilities	0	0
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	3,099,400	3,222,100
Noncontrolling interests in consolidated subsidiaries	0	0
Total equity	3,099,400	3,222,100
Total liabilities and equity	11,704,900	13,837,100
Reportable Legal Entities | Combined Non-Guarantor Subsidiaries
Current assets
Cash and cash equivalents	0	0	0	0
Accounts receivable, net	939,600	872,400
Natural gas and natural gas liquids in storage	314,300	140,000
Other current assets	242,400	160,600
Asset of discontinued operations		600
Total current assets	1,496,300	1,173,600
Property, plant and equipment
Property, plant and equipment	15,224,500	14,938,700
Accumulated depreciation and amortization	2,689,500	2,416,700
Net property, plant and equipment	12,535,000	12,522,000
Investments and other assets
Investments	809,100	631,100
Intercompany notes receivable	0	0
Other assets	1,015,900	1,028,000
Total investments and other assets	1,825,000	1,659,100
Total assets	15,856,300	15,354,700
Current liabilities
Current maturities of long-term debt	7,700	7,700
Short-term borrowings	0	0
Accounts payable	916,000	861,700
Other current liabilities	337,200	296,500
Total current liabilities	1,260,900	1,165,900
Intercompany debt	6,825,200	7,236,500
Long-term debt, excluding current maturities	30,700	36,600
Deferred credits and other liabilities	268,600	285,600
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	7,314,000	6,472,000
Noncontrolling interests in consolidated subsidiaries	156,900	158,100
Total equity	7,470,900	6,630,100
Total liabilities and equity	15,856,300	15,354,700
Reportable Legal Entities | Total
Current assets
Cash and cash equivalents	11,700	248,900	237,400	97,600
Accounts receivable, net	939,600	872,400
Natural gas and natural gas liquids in storage	314,300	140,000
Other current assets	253,300	167,800
Asset of discontinued operations		600
Total current assets	1,518,900	1,429,700
Property, plant and equipment
Property, plant and equipment	15,364,300	15,078,500
Accumulated depreciation and amortization	2,785,700	2,507,100
Net property, plant and equipment	12,578,600	12,571,400
Investments and other assets
Investments	1,013,700	958,800
Intercompany notes receivable	0	0
Other assets	1,653,600	1,178,900
Total investments and other assets	2,667,300	2,137,700
Total assets	16,764,800	16,138,800
Current liabilities
Current maturities of long-term debt	432,700	410,700
Short-term borrowings	932,300	1,110,300
Accounts payable	922,800	874,700
Other current liabilities	453,200	441,100
Total current liabilities	2,741,000	2,836,800
Intercompany debt	0	0
Long-term debt, excluding current maturities	8,092,000	7,920,000
Deferred credits and other liabilities	415,400	1,953,100
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	5,359,500	188,700
Noncontrolling interests in consolidated subsidiaries	156,900	3,240,200
Total equity	5,516,400	3,428,900
Total liabilities and equity	16,764,800	16,138,800
Consolidating Entries
Current assets
Cash and cash equivalents	0	0	$ 0	$ 0
Accounts receivable, net	0	0
Natural gas and natural gas liquids in storage	0	0
Other current assets	0	0
Asset of discontinued operations		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
Investments	(16,290,400)	(12,631,700)
Intercompany notes receivable	(15,430,700)	(17,851,500)
Other assets	(69,900)	0
Total investments and other assets	(31,791,000)	(30,483,200)
Total assets	(31,791,000)	(30,483,200)
Current liabilities
Current maturities of long-term debt	0	0
Short-term borrowings	0	0
Accounts payable	0	0
Other current liabilities	0	0
Total current liabilities	0	0
Intercompany debt	(15,430,700)	(17,851,500)
Long-term debt, excluding current maturities	0	0
Deferred credits and other liabilities	(69,900)	0
Commitments and contingencies
Equity
Equity excluding noncontrolling interests in consolidated subsidiaries	(16,290,400)	(15,713,800)
Noncontrolling interests in consolidated subsidiaries	0	3,082,100
Total equity	(16,290,400)	(12,631,700)
Total liabilities and equity	$ (31,791,000)	$ (30,483,200)

SUPPLEMENTAL CONDENSED CONSOL56

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION, Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Operating activities
Cash provided by operating activities			$ 935,996	$ 922,028
Investing activities
Capital expenditures	$ (135,199)	$ (158,274)	(330,431)	(491,528)
Contributions to unconsolidated affiliates			(87,653)	(55,177)
Cash used in investing activities			(394,597)	(484,588)
Financing activities
Dividends paid			(543,445)	(388,103)
Distributions to noncontrolling interests			(275,060)	(412,539)
Borrowing (repayment) of short-term borrowings, net			(178,027)	147,160
Issuance of long-term debt, net of discounts			1,190,067	1,000,000
Debt financing costs			(11,340)	(2,770)
Repayment of long-term debt			(992,864)	(656,117)
Issuance of common stock			45,849	14,948
Other			(13,778)	0
Cash used in financing activities			(778,598)	(297,421)
Change in cash and cash equivalents			(237,199)	140,019
Change in cash and cash equivalents included in discontinued operations			0	228
Change in cash and cash equivalents included in continuing operations			(237,199)	139,791
Cash and cash equivalents at beginning of period			248,875	97,619
Cash and cash equivalents at end of period	11,676	237,410	11,676	237,410
Reportable Legal Entities | Parent Issuer & Guarantor
Operating activities
Cash provided by operating activities			620,800	546,300
Investing activities
Capital expenditures			(500)	(100)
Contributions to unconsolidated affiliates			0
Other investing activities			0	0
Cash used in investing activities			(500)	(100)
Financing activities
Dividends paid			(543,400)	(388,100)
Distributions to noncontrolling interests			0	0
Intercompany borrowings (advances), net			(2,376,900)	(33,100)
Borrowing (repayment) of short-term borrowings, net			932,300	0
Issuance of long-term debt, net of discounts			1,190,100	0
Debt financing costs				0
Repayment of long-term debt			(87,100)	(300)
Issuance of common stock			45,800	14,900
Other			(17,900)
Cash used in financing activities			(857,100)	(406,600)
Change in cash and cash equivalents			(236,800)	139,600
Change in cash and cash equivalents included in discontinued operations				(200)
Change in cash and cash equivalents included in continuing operations				139,400
Cash and cash equivalents at beginning of period			248,500	92,500
Cash and cash equivalents at end of period	11,700	231,900	11,700	231,900
Reportable Legal Entities | Subsidiary Issuer & Guarantor
Operating activities
Cash provided by operating activities			994,300	998,300
Investing activities
Capital expenditures			0	0
Contributions to unconsolidated affiliates			0
Other investing activities			0	0
Cash used in investing activities			0	0
Financing activities
Dividends paid			(999,000)	(999,000)
Distributions to noncontrolling interests			0	0
Intercompany borrowings (advances), net			2,022,200	(493,700)
Borrowing (repayment) of short-term borrowings, net			(1,110,300)	147,200
Issuance of long-term debt, net of discounts			0	1,000,000
Debt financing costs				(2,800)
Repayment of long-term debt			(900,000)	(650,000)
Issuance of common stock			0	0
Other			(7,200)
Cash used in financing activities			(994,300)	(998,300)
Change in cash and cash equivalents			0	0
Change in cash and cash equivalents included in discontinued operations				0
Change in cash and cash equivalents included in continuing operations				0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	0	0	0	0
Reportable Legal Entities | Guarantor Subsidiary
Operating activities
Cash provided by operating activities			42,100	52,300
Investing activities
Capital expenditures			0	0
Contributions to unconsolidated affiliates			(83,000)
Other investing activities			11,200	30,000
Cash used in investing activities			(71,800)	30,000
Financing activities
Dividends paid			(999,000)	(999,000)
Distributions to noncontrolling interests			0	0
Intercompany borrowings (advances), net			1,028,300	917,100
Borrowing (repayment) of short-term borrowings, net			0	0
Issuance of long-term debt, net of discounts			0	0
Debt financing costs				0
Repayment of long-term debt			0	0
Issuance of common stock			0	0
Other			0
Cash used in financing activities			29,300	(81,900)
Change in cash and cash equivalents			(400)	400
Change in cash and cash equivalents included in discontinued operations				0
Change in cash and cash equivalents included in continuing operations				400
Cash and cash equivalents at beginning of period			400	5,100
Cash and cash equivalents at end of period	0	5,500	0	5,500
Reportable Legal Entities | Combined Non-Guarantor Subsidiaries
Operating activities
Cash provided by operating activities			1,005,800	916,700
Investing activities
Capital expenditures			(329,900)	(491,400)
Contributions to unconsolidated affiliates			(4,700)
Other investing activities			12,300	(23,100)
Cash used in investing activities			(322,300)	(514,500)
Financing activities
Dividends paid			0	0
Distributions to noncontrolling interests			(4,100)	(6,100)
Intercompany borrowings (advances), net			(673,600)	(390,300)
Borrowing (repayment) of short-term borrowings, net			0	0
Issuance of long-term debt, net of discounts			0	0
Debt financing costs				0
Repayment of long-term debt			(5,800)	(5,800)
Issuance of common stock			0	0
Other			0
Cash used in financing activities			(683,500)	(402,200)
Change in cash and cash equivalents			0	0
Change in cash and cash equivalents included in discontinued operations				0
Change in cash and cash equivalents included in continuing operations				0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	0	0	0	0
Reportable Legal Entities | Total
Operating activities
Cash provided by operating activities			936,000	922,000
Investing activities
Capital expenditures			(330,400)	(491,500)
Contributions to unconsolidated affiliates			(87,700)
Other investing activities			23,500	6,900
Cash used in investing activities			(394,600)	(484,600)
Financing activities
Dividends paid			(543,400)	(388,100)
Distributions to noncontrolling interests			(275,100)	(412,500)
Intercompany borrowings (advances), net			0	0
Borrowing (repayment) of short-term borrowings, net			(178,000)	147,200
Issuance of long-term debt, net of discounts			1,190,100	1,000,000
Debt financing costs				(2,800)
Repayment of long-term debt			(992,900)	(656,100)
Issuance of common stock			45,800	14,900
Other			(25,100)
Cash used in financing activities			(778,600)	(297,400)
Change in cash and cash equivalents			(237,200)	140,000
Change in cash and cash equivalents included in discontinued operations				(200)
Change in cash and cash equivalents included in continuing operations				139,800
Cash and cash equivalents at beginning of period			248,900	97,600
Cash and cash equivalents at end of period	11,700	237,400	11,700	237,400
Consolidating Entries
Operating activities
Cash provided by operating activities			(1,727,000)	(1,591,600)
Investing activities
Capital expenditures			0	0
Contributions to unconsolidated affiliates			0
Other investing activities			0	0
Cash used in investing activities			0	0
Financing activities
Dividends paid			1,998,000	1,998,000
Distributions to noncontrolling interests			(271,000)	(406,400)
Intercompany borrowings (advances), net			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
Repayment of long-term debt			0	0
Issuance of common stock			0	0
Other			0
Cash used in financing activities			1,727,000	1,591,600
Change in cash and cash equivalents			0	0
Change in cash and cash equivalents included in discontinued operations				0
Change in cash and cash equivalents included in continuing operations				0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	$ 0	$ 0	$ 0	$ 0