ONEOK (OKE) 10-Q30 Oct 192019 Q3 Quarterly reportFinancial data

Company Profile

Document and Entity Information

Document and Entity Information - shares	9 Months Ended
Document and Entity Information - shares	Sep. 30, 2019	Oct. 21, 2019
Document Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2019
Document Transition Report	false
Entity File Number	001-13643
Entity Registrant Name	ONEOK, Inc.
Entity Incorporation, State or Country Code	OK
Entity Tax Identification Number	73-1520922
Entity Address, Address Line One	100 West Fifth Street,
Entity Address, City or Town	Tulsa,
Entity Address, State or Province	OK
Entity Address, Postal Zip Code	74103
City Area Code	918
Local Phone Number	588-7000
Title of 12(b) Security	Common stock, par value of $0.01
Trading Symbol	OKE
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		413,084,650
Entity Central Index Key	0001039684
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2019
Document Fiscal Period Focus	Q3
Amendment Flag	false

CONSOLIDATED STATEMENTS OF INCO

CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Revenues
Revenues	$ 2,263,228	$ 3,393,890	$ 7,500,761	$ 9,456,496
Cost of sales and fuel (exclusive of items shown separately below)	1,414,528	2,560,765	4,996,699	7,104,609
Operations and maintenance	218,305	206,247	632,332	589,465
Depreciation and amortization	121,430	107,383	350,552	317,908
General taxes	26,830	24,124	91,257	81,263
(Gain) loss on sale of assets	(16)	(163)	2,882	(348)
Operating income	482,151	495,534	1,427,039	1,363,599
Equity in net earnings from investments (Note I)	37,576	39,313	115,175	116,070
Allowance for equity funds used during construction	15,792	2,294	45,175	3,328
Other income	6,643	5,072	21,685	7,667
Other expense	(6,065)	(3,404)	(14,024)	(11,104)
Interest expense (net of capitalized interest of $27,610, $8,326, $73,601 and $15,498, respectively)	(129,577)	(121,910)	(362,490)	(351,131)
Income before income taxes	406,520	416,899	1,232,560	1,128,429
Income taxes	(97,365)	(102,983)	(274,234)	(266,285)
Net income	309,155	313,916	958,326	862,144
Less: Net income attributable to noncontrolling interests	0	657	0	3,329
Net income attributable to ONEOK	309,155	313,259	958,326	858,815
Less: Preferred stock dividends	275	275	825	825
Net income available to common shareholders	$ 308,880	$ 312,984	$ 957,501	$ 857,990
Basic earnings per common share (Note G)	$ 0.75	$ 0.76	$ 2.32	$ 2.09
Diluted earnings per common share (Note G)	$ 0.74	$ 0.75	$ 2.31	$ 2.07
Average shares (thousands)
Basic	413,816	412,117	413,443	411,400
Diluted	415,578	414,847	415,277	414,035
Commodity Sales
Revenues
Revenues	$ 1,947,834	$ 3,083,625	$ 6,567,634	$ 8,578,891
Services
Revenues
Revenues	$ 315,394	$ 310,265	$ 933,127	$ 877,605

CONSOLIDATED STATEMENT OF INCOM

CONSOLIDATED STATEMENT OF INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Interest expense (net of capitalized interest)	$ 27,610	$ 8,326	$ 73,601	$ 15,498

CONSOLIDATED STATEMENTS OF COMP

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Net income	$ 309,155	$ 311,963	$ 337,208	$ 313,916	$ 282,179	$ 266,049	$ 958,326	$ 862,144
Other comprehensive income (loss), net of tax
Change in fair value of derivatives, net of tax of $22,050, $1,054, $59,679 and $(3,204), respectively	(73,822)			(3,526)			(199,795)	10,729
Derivative amounts reclassified to net income, net of tax of $2,673, $(5,752), $8,654 and $(12,962), respectively	(8,952)			19,261			(29,748)	43,397
Change in retirement and other postretirement benefit plan obligations, net of tax of $(737), $(966), $(2,172) and $(2,714), respectively	2,465			3,236			7,271	9,086
Other comprehensive income (loss) of unconsolidated affiliates, net of tax of $1,314, $(442), $3,164 and $(1,578), respectively	(4,399)			1,480			(10,593)	5,281
Total other comprehensive income (loss), net of tax	(84,708)	$ (66,872)	$ (81,285)	20,451	$ (3,897)	$ 51,939	(232,865)	68,493
Comprehensive income	224,447			334,367			725,461	930,637
Less: Comprehensive income attributable to noncontrolling interests	0			657			0	3,329
Comprehensive income attributable to ONEOK	$ 224,447			$ 333,710			$ 725,461	$ 927,308

CONSOLIDATED STATEMENTS OF CO_2

CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (PARANTHETICAL) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Change in fair value of derivatives, tax	$ 22,050	$ 1,054	$ 59,679	$ (3,204)
Derivative amounts reclassified to net income, tax	2,673	(5,752)	8,654	(12,962)
Change in retirement and other postretirement benefit plan obligations, tax	(737)	(966)	(2,172)	(2,714)
Other comprehensive income (loss) on investments in unconsolidated affiliates, tax	$ 1,314	$ (442)	$ 3,164	$ (1,578)

CONSOLIDATED BALANCE SHEETS

CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents	$ 673,309	$ 11,975
Accounts receivable, net	718,708	818,958
Materials and supplies	192,933	141,174
Natural gas and NGLs in storage	283,545	296,667
Commodity imbalances	19,327	29,050
Other current assets	79,763	100,808
Total current assets	1,967,585	1,398,632
Property, plant and equipment
Property, plant and equipment	20,948,267	18,030,963
Accumulated depreciation and amortization	3,585,411	3,264,312
Net property, plant and equipment	17,362,856	14,766,651
Investments and other assets
Investments in unconsolidated affiliates	870,511	969,150
Goodwill and intangible assets	960,808	967,142
Other assets	174,147	130,096
Total investments and other assets	2,005,466	2,066,388
Total assets	21,335,907	18,231,671
Current liabilities
Current maturities of long-term debt (Note D)	7,650	507,650
Accounts payable	1,129,849	1,116,337
Commodity imbalances	103,185	110,197
Accrued Taxes	79,358	61,337
Accrued interest	122,063	161,377
Finance lease liability (Note K)	1,901	1,765
Other current liabilities	123,146	149,773
Total current liabilities	1,567,152	2,108,436
Long-term debt, excluding current maturities	12,479,452	8,873,334
Deferred credits and other liabilities
Deferred income taxes	418,736	219,731
Finance lease liability (Note K)	24,801	26,244
Other deferred credits	626,860	424,383
Total deferred credits and other liabilities	1,070,397	670,358
Commitments and contingencies (Note J)
Equity (Note E)
Preferred stock, $0.01 par value: authorized and issued 20,000 shares at September 30, 2019, and December 31, 2018	0	0
Common stock, $0.01 par value: authorized 1,200,000,000 shares, issued 445,016,234 shares and outstanding 413,076,116 shares at September 30, 2019; issued 445,016,234 shares and outstanding 411,532,606 shares at December 31, 2018	4,450	4,450
Paid-in capital	7,448,099	7,615,138
Accumulated other comprehensive loss (Note F)	(421,104)	(188,239)
Retained earnings	0	0
Treasury stock, at cost: 31,940,118 shares at September 30, 2019, and 33,483,628 shares at December 31, 2018	(812,539)	(851,806)
Total equity	6,218,906	6,579,543
Total liabilities and equity	$ 21,335,907	$ 18,231,671

CONSOLIDATED BALANCE SHEETS (Pa

CONSOLIDATED BALANCE SHEETS (Parenthetical) - $ / shares	Sep. 30, 2019	Dec. 31, 2018
Equity (Note E)
Common stock, shares, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares, authorized (in shares)	1,200,000,000	1,200,000,000
Common stock, shares, issued (in shares)	445,016,234	445,016,234
Common stock, shares, outstanding (in shares)	413,076,116	411,532,606
Treasury stock, shares (in shares)	31,940,118	33,483,628
Preferred stock, shares, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares, issued (in shares)	20,000	20,000

CONSOLIDATED STATEMENTS OF CASH

CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018
Other Operating Activities, Cash Flow Statement	$ (1,200)	$ (3,250)
Operating activities
Net income	958,326	862,144
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	350,552	317,908
Equity in net earnings from investments	(115,175)	(116,070)
Distributions received from unconsolidated affiliates	121,176	125,824
Deferred income taxes	269,488	264,509
Share-based compensation expense	28,038	23,963
Allowance for equity funds used during construction	(45,175)	(3,328)
Changes in assets and liabilities:
Accounts receivable	100,250	117,876
Natural gas and NGLs in storage	13,122	(91,170)
Accounts payable	(162,806)	(41,837)
Commodity imbalances, net	2,711	15,379
Accrued interest	(39,314)	(23,562)
Risk-management assets and liabilities	(93,244)	66,966
Other assets and liabilities, net	(59,904)	1,098
Cash provided by operating activities	1,326,845	1,516,450
Investing activities
Capital expenditures (less allowance for equity funds used during construction)	(2,739,338)	(1,309,655)
Contributions to unconsolidated affiliates	(3,290)	(831)
Distributions received from unconsolidated affiliates in excess of cumulative earnings	82,171	19,613
Payments for (Proceeds from) Other Investing Activities	12,583	1,053
Cash used in investing activities	(2,647,874)	(1,289,820)
Financing activities
Dividends paid	(1,079,379)	(983,068)
Distributions to noncontrolling interests	0	(3,500)
Borrowing (repayment) of short-term borrowings, net	0	(494,673)
Issuance of long-term debt, net of discounts	4,185,435	1,245,773
Debt financing costs	(29,777)	(11,301)
Repayment of long-term debt	(1,055,436)	(930,738)
Issuance of common stock	19,333	1,195,128
Acquisition of noncontrolling interests	0	(195,000)
Other	(57,813)	(1,980)
Cash provided by (used in) financing activities	1,982,363	(179,359)
Change in cash and cash equivalents	661,334	47,271
Cash and cash equivalents at beginning of period	11,975	37,193
Cash and cash equivalents at end of period	$ 673,309	$ 84,464

CONSOLIDATED STATEMENT OF CHANG

CONSOLIDATED STATEMENT OF CHANGES IN EQUITY - USD ($) $ in Thousands	Total	Common Stock	Preferred Stock	Additional Paid-in Capital	Accumulated Other Comprehensive Income (Loss)	Retained Earnings	Treasury Stock	Noncontrolling Interests in Consolidated Subsidiaries
Cumulative effect adjustment for adoption of ASUs	$ 1,719	$ 0	$ 0	$ 0	$ (38,101)	$ 39,803	$ 0	$ 17
Shares, issued, beginning balance at Dec. 31, 2017		423,166,234	20,000
Total equity, beginning balance at Dec. 31, 2017	5,685,352	$ 4,232	$ 0	6,588,878	(188,530)	0	(876,713)	157,485
Net income	266,049	0	0	0	0	264,508	0	1,541
Other comprehensive income (loss)	51,939	0	0	0	51,939	0	0	0
Preferred stock dividends (Note E)	(275)	$ 0	0	(275)	0	0	0	0
Common Stock Issued During Period, Shares, Other		21,850,000
Common Stock Issued During Period, Value, Other	1,182,693	$ 218	0	1,169,247	0	0	13,228	0
Common Stock Dividends (Note E)	(316,271)	0	0	(11,960)	0	(304,311)	0	0
Distributions to Noncontrolling Interests	(1,500)	0	0	0	0	0	0	(1,500)
Contributions from noncontrolling interests	10,263	0	0	0	0	0	0	10,263
Other	(10,717)	$ 0	$ 0	(10,717)	0	0	0	0
Shares, issued, ending balance at Mar. 31, 2018		445,016,234	20,000
Total equity, ending balance at Mar. 31, 2018	6,869,252	$ 4,450	$ 0	7,735,173	(174,692)	0	(863,485)	167,806
Shares, issued, beginning balance at Dec. 31, 2017		423,166,234	20,000
Total equity, beginning balance at Dec. 31, 2017	5,685,352	$ 4,232	$ 0	6,588,878	(188,530)	0	(876,713)	157,485
Net income	862,144
Other comprehensive income (loss)	68,493
Shares, issued, ending balance at Sep. 30, 2018		445,016,234	20,000
Total equity, ending balance at Sep. 30, 2018	6,652,758	$ 4,450	$ 0	7,662,673	(158,138)	0	(856,227)	0
Shares, issued, beginning balance at Mar. 31, 2018		445,016,234	20,000
Total equity, beginning balance at Mar. 31, 2018	6,869,252	$ 4,450	$ 0	7,735,173	(174,692)	0	(863,485)	167,806
Net income	282,179	0	0	0	0	281,048	0	1,131
Other comprehensive income (loss)	(3,897)	0	0	0	(3,897)	0	0	0
Preferred stock dividends (Note E)	(275)	$ 0	0	275	0	(550)	0	0
Common Stock Issued During Period, Shares, Other		0
Common Stock Issued During Period, Value, Other	7,085	$ 0	0	4,535	0	0	2,550	0
Common Stock Dividends (Note E)	(327,325)	0	0	(46,827)	0	(280,498)	0	0
Distributions to Noncontrolling Interests	(1,500)	0	0	0	0	0	0	(1,500)
Contributions from noncontrolling interests	6,186	0	0	0	0	0	0	6,186
Other	6,778	$ 0	$ 0	6,778	0	0	0	0
Shares, issued, ending balance at Jun. 30, 2018		445,016,234	20,000
Total equity, ending balance at Jun. 30, 2018	6,838,483	$ 4,450	$ 0	7,699,934	(178,589)	0	(860,935)	173,623
Net income	313,916	0	0	0	0	313,259	0	657
Other comprehensive income (loss)	20,451	0	0	0	20,451	0	0	0
Preferred stock dividends (Note E)	(275)	$ 0	0	0	0	(275)	0	0
Common Stock Issued During Period, Shares, Other		0
Common Stock Issued During Period, Value, Other	9,429	$ 0	0	4,721	0	0	4,708	0
Common Stock Dividends (Note E)	(339,829)	0	0	(26,845)	0	(312,984)	0	0
Distributions to Noncontrolling Interests	(500)	$ 0	0	0	0	0	0	(500)
Stock Issued During Period, Shares, Acquisitions		0
Acquisition of noncontrolling interests	(195,000)	$ 0	0	(21,220)	0	0	0	(173,780)
Other	6,083	$ 0	$ 0	6,083	0	0	0	0
Shares, issued, ending balance at Sep. 30, 2018		445,016,234	20,000
Total equity, ending balance at Sep. 30, 2018	6,652,758	$ 4,450	$ 0	7,662,673	(158,138)	0	(856,227)	$ 0
Cumulative effect adjustment for adoption of ASUs	(67)	$ 0	$ 0	0	0	(67)	0
Shares, issued, beginning balance at Dec. 31, 2018		445,016,234	20,000
Total equity, beginning balance at Dec. 31, 2018	6,579,543	$ 4,450	$ 0	7,615,138
Total equity, beginning balance at Dec. 31, 2018	6,579,543				(188,239)	0	(851,806)
Net income	337,208	0	0	0	0	337,208	0
Other comprehensive income (loss)	(81,285)	0	0	0	(81,285)	0	0
Preferred stock dividends (Note E)	(275)	$ 0	0	0	0	(275)	0
Common Stock Issued During Period, Shares, Other		0
Common Stock Issued During Period, Value, Other	6,260	$ 0	0	(24,779)	0	0	31,039
Common Stock Dividends (Note E)	(354,304)	0	0	(17,438)	0	(336,866)	0
Other	(45,074)	$ 0	$ 0	(45,074)	0	0	0
Shares, issued, ending balance at Mar. 31, 2019		445,016,234	20,000
Total equity, ending balance at Mar. 31, 2019		$ 4,450	$ 0	7,527,847
Total equity, ending balance at Mar. 31, 2019	6,442,006				(269,524)	0	(820,767)
Shares, issued, beginning balance at Dec. 31, 2018		445,016,234	20,000
Total equity, beginning balance at Dec. 31, 2018	6,579,543	$ 4,450	$ 0	7,615,138
Total equity, beginning balance at Dec. 31, 2018	6,579,543				(188,239)	0	(851,806)
Net income	958,326
Other comprehensive income (loss)	(232,865)				(232,865)
Shares, issued, ending balance at Sep. 30, 2019		445,016,234	20,000
Total equity, ending balance at Sep. 30, 2019	6,218,906	$ 4,450	$ 0	7,448,099
Total equity, ending balance at Sep. 30, 2019	6,218,906				(421,104)	0	(812,539)
Shares, issued, beginning balance at Mar. 31, 2019		445,016,234	20,000
Total equity, beginning balance at Mar. 31, 2019		$ 4,450	$ 0	7,527,847
Total equity, beginning balance at Mar. 31, 2019	6,442,006				(269,524)	0	(820,767)
Net income	311,963	0	0	0	0	311,963	0
Other comprehensive income (loss)	(66,872)	0	0	0	(66,872)	0	0
Preferred stock dividends (Note E)	(275)	$ 0	0	0	0	(275)	0
Common Stock Issued During Period, Shares, Other		0
Common Stock Issued During Period, Value, Other	11,726	$ 0	0	6,335	0	0	5,391
Common Stock Dividends (Note E)	(357,416)	0	0	(45,728)	0	(311,688)	0
Other	7,004	$ 0	$ 0	7,004	0	0	0
Shares, issued, ending balance at Jun. 30, 2019		445,016,234	20,000
Total equity, ending balance at Jun. 30, 2019		$ 4,450	$ 0	7,495,458
Total equity, ending balance at Jun. 30, 2019	6,348,136				(336,396)	0	(815,376)
Net income	309,155	0	0	0	0	309,155	0
Other comprehensive income (loss)	(84,708)	0	0	0	(84,708)	0	0
Preferred stock dividends (Note E)	(275)	$ 0	0	0	0	(275)	0
Common Stock Issued During Period, Shares, Other		0
Common Stock Issued During Period, Value, Other	7,075	$ 0	0	4,238	0	0	2,837
Common Stock Dividends (Note E)	(367,840)	0	0	(58,960)	0	(308,880)	0
Other	7,363	$ 0	$ 0	7,363	0	0	0
Shares, issued, ending balance at Sep. 30, 2019		445,016,234	20,000
Total equity, ending balance at Sep. 30, 2019	6,218,906	$ 4,450	$ 0	$ 7,448,099
Total equity, ending balance at Sep. 30, 2019	$ 6,218,906				$ (421,104)	$ 0	$ (812,539)

CONSOLIDATED STATEMENT OF CHA_2

CONSOLIDATED STATEMENT OF CHANGES IN EQUITY CONSOLIDATED STATEMENT OF CHANGES IN EQUITY Parenthetical - $ / shares	3 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Statement of Stockholders' Equity [Abstract]
Preferred stock, dividends paid (in dollars per share)	$ 13.75	$ 13.75	$ 13.75	$ 13.75	$ 13.75	$ 13.75
Common stock, dividends paid (in dollars per share)	$ 0.89	$ 0.865	$ 0.86	$ 0.825	$ 0.795	$ 0.77

SUMMARY OF SIGNIFICANT ACCOUNTI

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Notes)	9 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Notes)	Sep. 30, 2019
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 2018 year-end Consolidated Balance Sheet data was derived from our audited Consolidated Financial Statements but does not include all disclosures required by GAAP. Certain reclassifications and revisions have been made in the prior-year Consolidated Financial Statements to conform to the current year presentation. See Note E for additional information. These unaudited Consolidated Financial Statements should be read in conjunction with our audited Consolidated Financial Statements in our Annual Report. 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 or in our Annual Report were assessed and determined to be either not applicable or clarifications of ASUs listed below. Except as discussed below or in our Annual Report, there have been no new accounting pronouncements that have become effective or have been issued that are of significance or potential significance to us. The following table provides a brief description of recently adopted 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 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 adopted this standard on January 1, 2019, using the modified retrospective method and the optional transition method to record the adoption impact through a cumulative adjustment to equity. We recorded an immaterial cumulative effect for the adoption of the new standard and recorded $17.5 million of right-of-use assets and $17.4 million of lease liabilities related to operating leases that were not previously recorded on our Consolidated Balance Sheets. Our finance lease assets and liabilities of $28.1 million and $28.0 million, respectively, did not change as a result of adopting this standard. See Note K for additional disclosures. ASU 2018-07, “Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting” The standard aligns the measurement and classification guidance for share-based payments to nonemployees with the guidance for share-based payments to employees, with certain exceptions. First quarter 2019 The impact of adopting this standard was not material. Goodwill Impairment Review

FAIR VALUE MEASUREMENTS (Notes)

FAIR VALUE MEASUREMENTS (Notes)	9 Months Ended
FAIR VALUE MEASUREMENTS (Notes)	Sep. 30, 2019
Fair Value Disclosures [Abstract]
FAIR VALUE MEASUREMENTS	FAIR VALUE MEASUREMENTS Determining Fair Value - For our fair value measurements, we utilize market prices, third-party pricing services, present value methods and standard option valuation models to determine the price we would receive from the sale of an asset or the transfer of a liability in an orderly transaction at the measurement date. 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 may utilize modeling techniques using NYMEX-settled pricing data and implied forward LIBOR curves. Inputs into our fair value estimates include commodity-exchange prices, data obtained from third-party pricing services, LIBOR and other liquid money-market instrument rates. Our financial commodity derivatives are generally settled through a NYMEX or Intercontinental Exchange (ICE) clearing broker account with daily margin requirements. We validate our valuation inputs with third-party information and settlement prices from other sources, where available. 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 the implied forward LIBOR yield curve. The fair value of our forward-starting interest-rate swaps is determined using financial models that incorporate the implied forward LIBOR yield curve for the same period as the future interest-rate swap settlements. We consider current market data in evaluating counterparties’, as well as our own, nonperformance risk, net of collateral, by using counterparty-specific bond yields. 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 materially from our estimates. 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. These balances are composed predominantly of exchange-traded derivative contracts for natural gas and crude oil. • Level 2 - fair value measurements are based on significant observable pricing inputs, including quoted prices for similar assets and liabilities in active markets and inputs from third-party pricing services supported with corroborative evidence. These balances are composed of over-the-counter interest-rate derivatives. • 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 and third-party pricing services. These balances are composed predominantly of exchange-cleared and over-the-counter derivatives for natural gas basis and NGLs. Our commodity derivatives are generally valued using forward quotes provided by third-party pricing services that are validated with other market data. We believe any measurement uncertainty at September 30, 2019 , is immaterial as our Level 3 fair value measurements are based on unadjusted pricing information from broker quotes and third-party pricing services. We do not believe that our Level 3 fair value estimates have a material impact on our results of operations, as our derivatives are accounted for as hedges. 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, 2019 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 12,267 $ — $ 68,049 $ 80,316 $ (40,413 ) $ 39,903 Physical contracts — — 579 579 — 579 Total derivative assets $ 12,267 $ — $ 68,628 $ 80,895 $ (40,413 ) $ 40,482 Derivative liabilities Commodity contracts Financial contracts $ — $ — $ (40,413 ) $ (40,413 ) $ 40,413 $ — Interest-rate contracts — (276,865 ) — (276,865 ) — (276,865 ) Total derivative liabilities $ — $ (276,865 ) $ (40,413 ) $ (317,278 ) $ 40,413 $ (276,865 ) (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, 2019 , we held no cash and posted $1.9 million of cash with various counterparties, which is included in other current assets in our Consolidated Balance Sheet. December 31, 2018 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 10,812 $ — $ 69,165 $ 79,977 $ (32,739 ) $ 47,238 Physical contracts — — 1,142 1,142 — 1,142 Interest-rate contracts — 19,005 — 19,005 — 19,005 Total derivative assets $ 10,812 $ 19,005 $ 70,307 $ 100,124 $ (32,739 ) $ 67,385 Derivative liabilities Commodity contracts Financial contracts $ (2,916 ) $ — $ (29,823 ) $ (32,739 ) $ 32,739 $ — Interest-rate contracts — (99,260 ) — (99,260 ) — (99,260 ) Total derivative liabilities $ (2,916 ) $ (99,260 ) $ (29,823 ) $ (131,999 ) $ 32,739 $ (99,260 ) (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, 2018 , we held no cash and posted $0.8 million of cash with various counterparties, which is included in other current assets in our Consolidated Balance Sheet. 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) 2019 2018 2019 2018 ( Thousands of dollars ) Net assets (liabilities) at beginning of period $ 19,274 $ (23,501 ) $ 40,484 $ (32,838 ) Total changes in fair value: Included in net income (a) — (22 ) — (122 ) Included in other comprehensive income (loss) (b) 8,941 (7,554 ) (12,269 ) 1,883 Net assets (liabilities) at end of period $ 28,215 $ (31,077 ) $ 28,215 $ (31,077 ) (a) - Included in commodity sales revenues/cost of sales and fuel in our Consolidated Statements of Income. (b) - Included in change in fair value of derivatives in our Consolidated Statements of Comprehensive Income. Changes in fair value include the realization of our derivative contracts through maturity. During the three and nine months ended September 30, 2019 and 2018 , there were no transfers in or out of Level 3 of the fair value hierarchy. 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 $ 13.7 billion and $9.6 billion at September 30, 2019 , and December 31, 2018 , respectively. The book value of our consolidated long-term debt, including current maturities, was $ 12.5 billion and $9.4 billion at September 30, 2019 , and December 31, 2018 , respectively. The estimated fair value of the aggregate long-term debt 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, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES	RISK-MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES Risk-Management Activities - We are sensitive to changes in natural gas, crude oil and NGL prices, principally as a result of contractual terms under which these commodities are processed, purchased and sold. We 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 may 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 primarily exposed to commodity price risk resulting from the relative values of the various NGL products to each other, the value of NGLs in storage and the relative value of NGLs to natural gas. We are also exposed to location price differential risk as a result of the relative value of NGL purchases at one location and sales at another location, primarily related to our optimization and marketing activities. As part of our hedging strategy, 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 pipelines consume natural gas in operations and retain natural gas from our customers for operations or as part of our fee for services provided. When the amount consumed in operations differs from the amount provided by our customers, our pipelines must buy or sell natural gas, or store or use natural gas from inventory, which can expose 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 natural gas price fluctuations. At September 30, 2019 , and December 31, 2018 , 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 2019, we entered into $625 million of forward-starting interest-rate swaps 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. We also settled $1.8 billion of our forward-starting interest-rate swaps related to our underwritten public offerings of $1.25 billion senior unsecured notes in March 2019 and $2.0 billion senior unsecured notes in August 2019. At September 30, 2019 , and December 31, 2018 , we had forward-starting interest-rate swaps with notional amounts totaling $1.8 billion and $3.0 billion , respectively, to hedge the variability of interest payments on a portion of our forecasted debt issuances. At September 30, 2019 , and December 31, 2018 , we had interest-rate swaps with notional amounts totaling $1.3 billion 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 - All derivatives measured at fair value at September 30, 2019, and December 31, 2018, were designated as hedging instruments. See Note B for a discussion of the inputs associated with our fair value measurements. The following table sets forth the fair values of our derivative instruments presented on a gross basis for the periods indicated: September 30, 2019 December 31, 2018 Location in our Consolidated Balance Sheets Assets (Liabilities) Assets (Liabilities) ( Thousands of dollars ) Derivatives designated as hedging instruments Commodity contracts (a) Financial contracts Other current assets $ 72,995 $ (36,186 ) $ 78,891 $ (31,793 ) Other assets 7,321 (4,227 ) 1,086 (946 ) Physical contracts Other current assets 579 — 1,142 — Interest-rate contracts Other current assets/other current liabilities — (14,672 ) 19,005 (15,012 ) Other deferred credits — (262,193 ) — (84,248 ) Total derivatives designated as hedging instruments $ 80,895 $ (317,278 ) $ 100,124 $ (131,999 ) (a) - Derivative assets and liabilities are presented in our Consolidated Balance Sheets on a net basis when a legally enforceable master-netting arrangement exists between the counterparty to a derivative contract and us. Notional Quantities for Derivative Instruments - The following table sets forth the notional quantities for derivative instruments held for the periods indicated: September 30, 2019 December 31, 2018 Contract Type Purchased/ Payor Sold/ Receiver Purchased/ Payor Sold/ Receiver Derivatives designated as hedging instruments: Cash flow hedges Fixed price - Natural gas ( Bcf ) Futures and swaps — (39.6 ) — (29.9 ) - Crude oil and NGLs ( MMBbl ) Futures, forwards, swaps and options 9.2 (20.1 ) 6.5 (13.8 ) Basis - Natural gas ( Bcf ) Futures and swaps — (39.6 ) — (29.9 ) Interest-rate contracts ( Billions of dollars ) Swaps $ 3.1 $ — $ 4.3 $ — 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 - The following table sets forth the unrealized change in fair value of cash flow hedges 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, 2019 2018 2019 2018 ( Thousands of dollars ) Commodity contracts $ 32,169 $ (30,783 ) $ 43,877 $ (56,246 ) Interest-rate contracts (128,041 ) 26,203 (303,351 ) 70,179 Total unrealized change in fair value of cash flow hedges in other comprehensive income (loss) $ (95,872 ) $ (4,580 ) $ (259,474 ) $ 13,933 The following table sets forth the effect of cash flow hedges on net income for the periods indicated: Derivatives in Cash Flow Hedging Relationships Location of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Net Income Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 ( Thousands of dollars ) Commodity contracts Commodity sales revenues/ cost of sales and fuel $ 18,528 $ (20,630 ) $ 52,624 $ (42,430 ) Interest-rate contracts Interest expense (6,903 ) (4,383 ) (14,222 ) (13,929 ) Total change in fair value of cash flow hedges reclassified from accumulated other comprehensive loss into net income $ 11,625 $ (25,013 ) $ 38,402 $ (56,359 ) 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 use internally developed credit ratings for counterparties that do not have a credit rating. Our financial commodity derivatives are generally settled through a NYMEX or Intercontinental Exchange (ICE) clearing broker account with daily margin requirements. However, 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, 2019 . The counterparties to our derivative contracts typically consist 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, 2019 , the 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
DEBT DEBT (Notes)	Sep. 30, 2019
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 ) Commercial paper outstanding $ — $ — Senior unsecured obligations: $500,000 at 8.625% due March 2019 — 500,000 $300,000 at 3.8% due March 2020 — 300,000 $1,500,000 term loan, variable rate, due November 2021 1,250,000 550,000 $700,000 at 4.25% due February 2022 547,397 547,397 $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 7.5% due September 2023 500,000 500,000 $500,000 at 2.75% due September 2024 500,000 — $500,000 at 4.9% due March 2025 500,000 500,000 $500,000 at 4.0% due July 2027 500,000 500,000 $800,000 at 4.55% due July 2028 800,000 800,000 $100,000 at 6.875% due September 2028 100,000 100,000 $700,000 at 4.35% due March 2029 700,000 — $750,000 at 3.4% due September 2029 750,000 — $400,000 at 6.0% due June 2035 400,000 400,000 $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 $700,000 at 4.95% due July 2047 700,000 700,000 $1,000,000 at 5.2% due July 2048 1,000,000 450,000 $750,000 at 4.45% due September 2049 750,000 — Guardian Pipeline Weighted average 7.85% due December 2022 23,220 28,957 Total debt 12,595,617 9,451,354 Unamortized portion of terminated swaps 15,461 16,750 Unamortized debt issuance costs and discounts (123,976 ) (87,120 ) Current maturities of long-term debt (7,650 ) (507,650 ) Long-term debt $ 12,479,452 $ 8,873,334 $2.5 Billion Credit Agreement - In May 2019, we extended the term of our $2.5 Billion Credit Agreement by one year to June 2024. Our $2.5 Billion Credit Agreement is a 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 $2.5 Billion Credit Agreement, adjusted for all noncash charges and increased for projected EBITDA from certain lender-approved capital expansion projects) of no more than 5.0 to 1 at September 30, 2019 . 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. Thereafter, the covenant will decrease to 5.0 to 1. At September 30, 2019 , we had no borrowings outstanding, our ratio of indebtedness to adjusted EBITDA was 4.2 to 1, and we were in compliance with all covenants under our $2.5 Billion Credit Agreement. Debt Issuances - In August 2019, we completed an underwritten public offering of $2.0 billion senior unsecured notes consisting of $500 million , 2.75% senior notes due 2024; $750 million , 3.4% senior notes due 2029; and $750 million , 4.45% senior notes due 2049. The net proceeds, after deducting underwriting discounts, commissions and offering expenses, were $1.97 billion . A portion of the proceeds were, and the remainder will be, used for general corporate purposes, including repayment of existing indebtedness and funding capital expenditures. In March 2019, we completed an underwritten public offering of $1.25 billion senior unsecured notes consisting of $700 million , 4.35% senior notes due 2029 and an additional issuance of $550 million of our existing 5.2% senior notes due 2048. The net proceeds, after deducting underwriting discounts, commissions and offering expenses, and exclusive of accrued interest, were $1.23 billion . The proceeds were used for general corporate purposes, including repayment of existing indebtedness and funding capital expenditures. In November 2018, we entered into our $1.5 Billion Term Loan Agreement with a syndicate of banks, which was fully drawn as of June 30, 2019. We repaid $250 million of our outstanding balance in August 2019 and have $1.25 billion drawn as of September 30, 2019. Our $1.5 Billion Term Loan Agreement matures in November 2021 and bears interest at LIBOR plus 112.5 basis points bas ed on our current credit ratings. The agreement contains substantially the same covenants as those contained in our $2.5 Billion Credit Agreement. The proceeds were used for general corporate purposes, including repayment of existing indebtedness and funding capital expenditures. Debt Repayments - In September 2019, we redeemed our $300 million , 3.8% senior notes due March 2020 at a redemption price of $308.0 million , including the outstanding principal, plus accrued and unpaid interest, with cash on hand from our public offering of $2.0 billion senior unsecured notes in August 2019. In connection with this early redemption, we incurred a $2.7 million loss on extinguishment of debt, which is included in other expense in our Consolidated Statements of Income for the three and nine months ended September 30, 2019 . In August 2019, we repaid $250 million of our $1.5 Billion Term Loan Agreement with cash on hand. In March 2019, we repaid our $500 million , 8.625% senior notes at maturity with a combination of cash on hand and short-term borrowings. For additional discussion of our $2.5 Billion Credit Agreement and our $1.5 Billion Term Loan Agreement, see Note F of the Notes to Consolidated Financial Statements in our Annual Report.

EQUITY (Notes)

EQUITY (Notes)	9 Months Ended
EQUITY (Notes)	Sep. 30, 2019
Equity [Abstract]
EQUITY	EQUITY Noncontrolling Interests - In July 2018, we acquired the remaining 20% interest that we did not own in WTLPG for $195 million with cash on hand. We are now the sole owner of the West Texas LPG pipeline system. In our consolidated statement of cash flows for the nine months ended September 30, 2018, our acquisition of noncontrolling interests in WTLPG should have been classified as a financing activity instead of an investing activity. The consolidated statement of cash flows for the nine months ended September 30, 2018, has been revised to reflect this change in classification to financing, which was not material to our consolidated financial statements. 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. No shares have been sold through our “at-the-market” equity program since December 2017. In January 2018, we completed an underwritten public offering of 21.9 million shares of our common stock, generating net proceeds of $1.2 billion . We used the net proceeds from this offering to fund capital expenditures and for general corporate purposes, which included repaying a portion of our outstanding indebtedness. 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 in February 2019, May 2019 and August 2019 were $0.86 , $0.865 and $0.89 per share, respectively. A dividend of $0.915 per share was declared for shareholders of record at the close of business on November 4, 2019 , payable November 14, 2019 . 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% per year. We paid dividends for the Series E Preferred Stock of $0.3 million in February 2019, May 2019 and August 2019. Dividends totaling $0.3 million were declared for the Series E Preferred Stock and are payable November 14, 2019 .

ACCUMULATED OTHER COMPREHENSIVE

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ACCUMULATED OTHER COMPREHENSIVE INCOME (Notes)	9 Months Ended
	Sep. 30, 2019
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: Risk- Management Assets/Liabilities (a) Retirement and Other Postretirement Benefit Plan Obligations (a) (b) Risk- Management Assets/Liabilities of Unconsolidated Affiliates (a) Accumulated Other Comprehensive Loss (a) ( Thousands of dollars ) January 1, 2019 $ (64,660 ) $ (121,785 ) $ (1,794 ) $ (188,239 ) Other comprehensive loss before reclassifications (199,795 ) (63 ) (10,567 ) (210,425 ) Amounts reclassified to net income (29,748 ) 7,334 (26 ) (22,440 ) Other comprehensive income (loss) (229,543 ) 7,271 (10,593 ) (232,865 ) September 30, 2019 $ (294,203 ) $ (114,514 ) $ (12,387 ) $ (421,104 ) (a) - All amounts are presented net of tax. (b) - Includes amounts related to supplemental executive retirement plan. The following table sets forth information about the balance of accumulated other comprehensive loss at September 30, 2019 , representing unrealized gains (losses) related to risk-management assets and liabilities: Risk- Management Assets/Liabilities (a) ( Thousands of dollars ) Commodity derivative instruments expected to be realized within the next 27 months (b) $ 30,258 Settled interest-rate swaps to be recognized over the life of the long-term, fixed-rate debt (c) (111,275 ) Interest-rate swaps with future settlement dates expected to be amortized over the life of long-term debt (213,186 ) Accumulated other comprehensive loss at September 30, 2019 $ (294,203 ) (a) - All amounts are presented net of tax. (b) - Based on September 30, 2019 , commodity prices, we will realize $27.9 million in net gains, net of tax, over the next 12 months and $2.4 million in net gains, net of tax, thereafter. (c) - Losses of $19.7 million , net of tax, will be reclassified into earnings during the next 12 months as the hedged items affect earnings. The remaining amounts in accumulated other comprehensive loss relate primarily to our retirement and other postretirement benefit plan obligations, which are expected to be amortized over the average remaining service period of employees participating in these plans. The following table sets forth the effect of reclassifications from accumulated other comprehensive loss to net 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, 2019 2018 2019 2018 ( Thousands of dollars ) Risk-management assets/liabilities Commodity contracts $ 18,528 $ (20,630 ) $ 52,624 $ (42,430 ) Commodity sales revenues/cost of sales and fuel Interest-rate contracts (6,903 ) (4,383 ) (14,222 ) (13,929 ) Interest expense 11,625 (25,013 ) 38,402 (56,359 ) Income before income taxes (2,673 ) 5,752 (8,654 ) 12,962 Income taxes $ 8,952 $ (19,261 ) $ 29,748 $ (43,397 ) Net income Retirement and other postretirement benefit plan obligations (a) Amortization of net loss $ (3,232 ) $ (4,592 ) $ (9,696 ) $ (13,776 ) Other income (expense) Amortization of unrecognized prior service credit 57 415 171 1,245 Other income (expense) (3,175 ) (4,177 ) (9,525 ) (12,531 ) Income before income taxes 731 961 2,191 2,882 Income taxes $ (2,444 ) $ (3,216 ) $ (7,334 ) $ (9,649 ) Net income Risk-management assets/liabilities of unconsolidated affiliates Interest-rate contracts $ (59 ) $ 52 $ 34 $ 71 Equity in net earnings from investments 13 (12 ) (8 ) (16 ) Income taxes $ (46 ) $ 40 $ 26 $ 55 Net income Total reclassifications for the period $ 6,462 $ (22,437 ) $ 22,440 $ (52,991 ) Net income (a) - These components of accumulated other comprehensive loss are included in the computation of net periodic benefit cost. See Note H for additional detail of our net periodic benefit cost.

EARNINGS PER SHARE EARNINGS PER

EARNINGS PER SHARE EARNINGS PER SHARE (Notes)	9 Months Ended
EARNINGS PER SHARE EARNINGS PER SHARE (Notes)	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share [Text Block]	EARNINGS PER SHARE The following tables set forth the computation of basic and diluted EPS for the periods indicated: Three Months Ended September 30, 2019 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Net income available for common stock $ 308,880 413,816 $ 0.75 Diluted EPS Effect of dilutive securities — 1,762 Net income available for common stock and common stock equivalents $ 308,880 415,578 $ 0.74 Three Months Ended September 30, 2018 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Net income attributable to ONEOK available for common stock $ 312,984 412,117 $ 0.76 Diluted EPS Effect of dilutive securities — 2,730 Net income attributable to ONEOK available for common stock and common stock equivalents $ 312,984 414,847 $ 0.75 Nine Months Ended September 30, 2019 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Net income available for common stock $ 957,501 413,443 $ 2.32 Diluted EPS Effect of dilutive securities — 1,834 Net income available for common stock and common stock equivalents $ 957,501 415,277 $ 2.31 Nine Months Ended September 30, 2018 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Net income attributable to ONEOK available for common stock $ 857,990 411,400 $ 2.09 Diluted EPS Effect of dilutive securities — 2,635 Net income attributable to ONEOK available for common stock and common stock equivalents $ 857,990 414,035 $ 2.07

EMPLOYEE BENEFIT PLANS EMPLOYEE

EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS (Notes)	9 Months Ended
EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS (Notes)	Sep. 30, 2019
Defined Benefit Plan [Abstract]
EMPLOYEE BENEFIT PLANS	EMPLOYEE BENEFIT PLANS The following tables set forth the components of net periodic benefit cost (income) for our retirement and other postretirement benefit plans for the periods indicated: Retirement Benefits Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 ( Thousands of dollars ) Components of net periodic benefit cost Service cost $ 1,954 $ 1,832 $ 5,862 $ 5,496 Interest cost 5,126 4,408 15,378 13,224 Expected return on plan assets (5,892 ) (5,969 ) (17,676 ) (17,907 ) Amortization of net loss 3,158 4,258 9,474 12,774 Net periodic benefit cost $ 4,346 $ 4,529 $ 13,038 $ 13,587 Other Postretirement Benefits Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 ( Thousands of dollars ) Components of net periodic benefit cost Service cost $ 117 $ 211 $ 351 $ 633 Interest cost 509 527 1,527 1,581 Expected return on plan assets (570 ) (672 ) (1,710 ) (2,016 ) Amortization of prior service credit (57 ) (415 ) (171 ) (1,245 ) Amortization of net loss 74 334 222 1,002 Net periodic benefit cost (income) $ 73 $ (15 ) $ 219 $ (45 )

UNCONSOLIDATED AFFILIATES (Note

UNCONSOLIDATED AFFILIATES (Notes)	9 Months Ended
UNCONSOLIDATED AFFILIATES (Notes)	Sep. 30, 2019
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 (loss) from investments for the periods indicated: Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 ( Thousands of dollars ) Northern Border Pipeline $ 16,102 $ 16,486 $ 50,593 $ 48,863 Overland Pass Pipeline 15,481 16,081 48,340 48,714 Roadrunner 7,421 6,303 19,836 16,803 Other (1,428 ) 443 (3,594 ) 1,690 Equity in net earnings from investments $ 37,576 $ 39,313 $ 115,175 $ 116,070 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, 2019 2018 2019 2018 ( Thousands of dollars ) Income Statement Revenues $ 151,210 $ 160,962 $ 471,461 $ 471,641 Operating expenses $ 69,783 $ 69,004 $ 217,287 $ 205,525 Net income $ 74,341 $ 85,361 $ 234,154 $ 247,754 Distributions paid to us (a) $ 44,357 $ 47,197 $ 203,347 $ 145,437 (a) - As determined by the Northern Border Pipeline Management Committee, we received an additional distribution of $50.0 million from Northern Border Pipeline during the nine months ended September 30, 2019. We incurred expenses in transactions with unconsolidated affiliates of $41.9 million and $37.5 million for the three months ended September 30, 2019 and 2018 , respectively, and $124.2 million and $113.2 million for the nine months ended September 30, 2019 and 2018 , respectively, primarily related to Overland Pass Pipeline and Northern Border Pipeline. Accounts payable to our equity-method investees at September 30, 2019 , and December 31, 2018 , were $13.8 million and $14.7 million , respectively. 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, 2019 and 2018

COMMITMENTS AND CONTINGENCIES (

COMMITMENTS AND CONTINGENCIES (Notes)	9 Months Ended
COMMITMENTS AND CONTINGENCIES (Notes)	Sep. 30, 2019
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 laws and regulations that relate to facility/pipeline safety and integrity as well as air and water quality, hazardous and solid waste management and disposal, cultural resource protection and other environmental matters. The cost of planning, designing, constructing and operating pipelines, plants and other facilities must incorporate compliance with these 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 or construction. 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 previously reported, we and our affiliate, ONEOK Energy Services Company, L.P., along with several other energy companies, were named as defendants in multiple lawsuits arising from alleged market manipulation or false reporting of natural gas prices to natural gas-index publications alleged to have occurred prior to 2003. In September 2019, we settled Sinclair Oil Corporation v. ONEOK Energy Services Company, L.P. (filed in the United States District Court for the District of Wyoming) for an immaterial amount with cash on hand. This was the last remaining case arising from the Gas Index Pricing Litigation. 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.

LEASES (Notes)

LEASES (Notes)	9 Months Ended
LEASES (Notes)	Sep. 30, 2019
Leases [Abstract]
Lessee, Operating Leases [Text Block]	LEASES Adoption of ASC Topic 842: Leases - We adopted Topic 842 using the modified retrospective method and the optional transition method to record the adoption impact through a cumulative-effect adjustment to retained earnings as of January 1, 2019. Results for reporting periods beginning after January 1, 2019, are presented under Topic 842, while prior periods are not adjusted and continue to be reported under the accounting standards in effect for those periods. Practical Expedients and Policies Elected - We applied the short-term policy election, which allows us to exclude from recognition leases with an initial term of 12 months or less. We elected the hindsight expedient, which allows us to use hindsight in assessing lease term; the package of practical expedients permitted under the guidance, which among other things, allows us to carry forward the historical lease classification; and the land easement expedient, which allows us to apply the guidance prospectively at adoption for land easements on existing agreements. Adoption - Adoption of Topic 842 resulted in new operating lease assets and lease liabilities on our Consolidated Balance Sheet of $17.5 million and $17.4 million , respectively, as of January 1, 2019. The difference between the lease assets and lease liabilities was recorded as an adjustment to the beginning balance of retained earnings, which represents the cumulative impact of adopting the standard. Our accounting for finance leases did not change. Adoption of Topic 842 did not materially impact our Consolidated Financial Statements. Leases - We lease certain buildings, warehouses, office space, land and equipment, including pipeline equipment, rail cars and information technology equipment. Our lease payments are generally straight-line and the exercise of lease renewal options, which vary in term, is at our sole discretion. We include renewal periods in a lease term if we are reasonably certain to exercise available renewal options. Our lease agreements do not include any residual value guarantees or material restrictive covenants. Through ONEOK Leasing Company, L.L.C. and ONEOK Parking Company, L.L.C., we own an office building and a parking garage and lease excess space in these facilities to affiliates and others. Our consolidated lease income is not material. The following table sets forth information about our supplemental cash flows: Nine Months Ended September 30, 2019 ( Thousands of dollars ) Cash paid for amounts included in the measurement of lease liabilities Operating cash flows for operating leases $ 4,972 Financing cash flows for finance lease $ 1,307 Right-of-use assets obtained in exchange for operating lease liabilities (noncash) $ 3,663 The following table sets forth information about our lease assets and liabilities included in our Consolidated Balance Sheet for the period indicated: Leases Location in our Consolidated Balance Sheet September 30, 2019 ( Thousands of dollars ) Assets Operating leases Other assets $ 16,176 Finance lease Property, plant and equipment 28,286 Finance lease Accumulated depreciation (1,037 ) Total leased assets $ 43,425 Liabilities Current Operating leases Other current liabilities $ 2,624 Finance lease Finance lease liability 1,901 Noncurrent Operating leases Other deferred credits 13,790 Finance lease Finance lease liability 24,801 Total lease liabilities $ 43,116 The following table sets forth information about our leases for the periods indicated: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 At September 30, 2019 Location in our Consolidated Statement of Income Lease Cost Weighted-Average Remaining Lease Term Weighted-Average Discount Rate (a) ( Thousands of dollars ) ( Years ) Operating leases Operations and maintenance $ 1,751 $ 5,402 10.1 4.58% Finance lease 9.1 10.00% Amortization of lease assets Depreciation and amortization 283 849 Interest on lease liabilities Interest expense 675 2,058 Total lease cost $ 2,709 $ 8,309 (a) - Our weighted-average discount rates represent the rate implicit in the lease or our incremental borrowing rate for a term equal to the remaining term of the lease. The following table sets forth the maturity of our lease liabilities as of September 30, 2019 : Finance Lease Operating Leases ( Millions of dollars ) Remainder of 2019 $ 1.1 $ 1.3 2020 4.5 2.4 2021 4.5 2.0 2022 4.5 2.0 2023 4.5 1.9 2024 and beyond 21.6 11.1 Total lease payments 40.7 20.7 Less: Interest 14.0 4.3 Present value of lease liabilities $ 26.7 $ 16.4 Our future lease payments presented under the previous accounting standard as of December 31, 2018, are not materially different than those presented above.
Lessee, Finance Leases [Text Block]	LEASES Adoption of ASC Topic 842: Leases - We adopted Topic 842 using the modified retrospective method and the optional transition method to record the adoption impact through a cumulative-effect adjustment to retained earnings as of January 1, 2019. Results for reporting periods beginning after January 1, 2019, are presented under Topic 842, while prior periods are not adjusted and continue to be reported under the accounting standards in effect for those periods. Practical Expedients and Policies Elected - We applied the short-term policy election, which allows us to exclude from recognition leases with an initial term of 12 months or less. We elected the hindsight expedient, which allows us to use hindsight in assessing lease term; the package of practical expedients permitted under the guidance, which among other things, allows us to carry forward the historical lease classification; and the land easement expedient, which allows us to apply the guidance prospectively at adoption for land easements on existing agreements. Adoption - Adoption of Topic 842 resulted in new operating lease assets and lease liabilities on our Consolidated Balance Sheet of $17.5 million and $17.4 million , respectively, as of January 1, 2019. The difference between the lease assets and lease liabilities was recorded as an adjustment to the beginning balance of retained earnings, which represents the cumulative impact of adopting the standard. Our accounting for finance leases did not change. Adoption of Topic 842 did not materially impact our Consolidated Financial Statements. Leases - We lease certain buildings, warehouses, office space, land and equipment, including pipeline equipment, rail cars and information technology equipment. Our lease payments are generally straight-line and the exercise of lease renewal options, which vary in term, is at our sole discretion. We include renewal periods in a lease term if we are reasonably certain to exercise available renewal options. Our lease agreements do not include any residual value guarantees or material restrictive covenants. Through ONEOK Leasing Company, L.L.C. and ONEOK Parking Company, L.L.C., we own an office building and a parking garage and lease excess space in these facilities to affiliates and others. Our consolidated lease income is not material. The following table sets forth information about our supplemental cash flows: Nine Months Ended September 30, 2019 ( Thousands of dollars ) Cash paid for amounts included in the measurement of lease liabilities Operating cash flows for operating leases $ 4,972 Financing cash flows for finance lease $ 1,307 Right-of-use assets obtained in exchange for operating lease liabilities (noncash) $ 3,663 The following table sets forth information about our lease assets and liabilities included in our Consolidated Balance Sheet for the period indicated: Leases Location in our Consolidated Balance Sheet September 30, 2019 ( Thousands of dollars ) Assets Operating leases Other assets $ 16,176 Finance lease Property, plant and equipment 28,286 Finance lease Accumulated depreciation (1,037 ) Total leased assets $ 43,425 Liabilities Current Operating leases Other current liabilities $ 2,624 Finance lease Finance lease liability 1,901 Noncurrent Operating leases Other deferred credits 13,790 Finance lease Finance lease liability 24,801 Total lease liabilities $ 43,116 The following table sets forth information about our leases for the periods indicated: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 At September 30, 2019 Location in our Consolidated Statement of Income Lease Cost Weighted-Average Remaining Lease Term Weighted-Average Discount Rate (a) ( Thousands of dollars ) ( Years ) Operating leases Operations and maintenance $ 1,751 $ 5,402 10.1 4.58% Finance lease 9.1 10.00% Amortization of lease assets Depreciation and amortization 283 849 Interest on lease liabilities Interest expense 675 2,058 Total lease cost $ 2,709 $ 8,309 (a) - Our weighted-average discount rates represent the rate implicit in the lease or our incremental borrowing rate for a term equal to the remaining term of the lease. The following table sets forth the maturity of our lease liabilities as of September 30, 2019 : Finance Lease Operating Leases ( Millions of dollars ) Remainder of 2019 $ 1.1 $ 1.3 2020 4.5 2.4 2021 4.5 2.0 2022 4.5 2.0 2023 4.5 1.9 2024 and beyond 21.6 11.1 Total lease payments 40.7 20.7 Less: Interest 14.0 4.3 Present value of lease liabilities $ 26.7 $ 16.4 Our future lease payments presented under the previous accounting standard as of December 31, 2018, are not materially different than those presented above.

REVENUE REVENUE (Notes)

REVENUE REVENUE (Notes)	9 Months Ended
REVENUE REVENUE (Notes)	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Text Block]	REVENUES Accounting Policies - Our revenue recognition policy is described in Note A of the Notes to Consolidated Financial Statements in our Annual Report. Contract Assets and Contract Liabilities - The following tables set forth the balances in contract assets and contract liabilities for the periods indicated: Contract Assets ( Millions of dollars ) Balance at December 31, 2018 (a) $ 6.2 Amounts invoiced in excess of revenue recognized (0.9 ) Net additions 0.8 Balance at September 30, 2019 (b) $ 6.1 (a) - Contract assets of $1.7 million and $4.5 million are included in other current assets and other assets, respectively, in our Consolidated Balance Sheets. (b) - Contract assets of $2.4 million and $3.7 million are included in other current assets and other assets, respectively, in our Consolidated Balance Sheets. Contract Liabilities ( Millions of dollars ) Balance at December 31, 2018 (a) $ 31.7 Revenue recognized included in beginning balance (15.2 ) Net additions 28.9 Balance at September 30, 2019 (b) $ 45.4 (a) - Contract liabilities of $15.6 million and $16.1 million are included in other current liabilities and other deferred credits, respectively, in our Consolidated Balance Sheets. (b) - Contract liabilities of $25.2 million and $20.2 million are included in other current liabilities and other deferred credits, respectively, in our Consolidated Balance Sheets. Receivables from Customers and Revenue Disaggregation - Substantially all of the balances in accounts receivable on our Consolidated Balance Sheets at September 30, 2019 , and December 31, 2018 , relate to customer receivables. Revenues sources are disaggregated in Note M. Practical Expedients - We do not disclose the value of unsatisfied performance obligations for (i) contracts with an original expected length of one year or less and (ii) variable consideration on contracts for which we recognize revenue at the amount to which we have the right to invoice for services performed. Transaction Price Allocated to Unsatisfied Performance Obligations - The following table presents aggregate value allocated to unsatisfied performance obligations as of September 30, 2019 , and the amounts we expect to recognize in revenue in future periods, related primarily to firm transportation and storage contracts with remaining contract terms ranging from one month to 24 years: Expected Period of Recognition in Revenue ( Millions of dollars ) Remainder of 2019 $ 101.5 2020 335.6 2021 286.3 2022 228.3 2023 and beyond 952.5 Total estimated transaction price allocated to unsatisfied performance obligations $ 1,904.2 The table above excludes variable consideration allocated entirely to wholly unsatisfied performance obligations, wholly unsatisfied promises to transfer distinct goods or services that are part of a single performance obligation and consideration we determine to be fully constrained. The amounts we determined to be fully constrained relate to future sales obligations under long-term sales contracts where the transaction price is not known and minimum volume agreements, which we consider to be fully constrained until invoiced.

SEGMENTS (Notes)

SEGMENTS (Notes)	9 Months Ended
SEGMENTS (Notes)	Sep. 30, 2019
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 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. 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 Segments ( Thousands of dollars ) NGL and condensate sales $ 244,932 $ 1,746,630 $ — $ 1,991,562 Residue natural gas sales 185,303 — 231 185,534 Gathering, processing and exchange services revenue 42,795 105,179 — 147,974 Transportation and storage revenue — 46,407 108,384 154,791 Other 3,182 2,291 12,933 18,406 Total revenues (c) 476,212 1,900,507 121,548 2,498,267 Cost of sales and fuel (exclusive of depreciation and operating costs) (210,739 ) (1,438,206 ) (381 ) (1,649,326 ) Operating costs (91,227 ) (114,903 ) (40,170 ) (246,300 ) Equity in net earnings (loss) from investments (1,837 ) 15,890 23,523 37,576 Noncash compensation expense and other 2,883 4,174 (701 ) 6,356 Segment adjusted EBITDA $ 175,292 $ 367,462 $ 103,819 $ 646,573 Depreciation and amortization $ (55,781 ) $ (50,419 ) $ (14,330 ) $ (120,530 ) Capital expenditures $ 245,745 $ 738,038 $ 27,767 $ 1,011,550 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $379.7 million , of which $315.7 million related to revenues within the segment, and cost of sales and fuel of $129.5 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $72.3 million and cost of sales and fuel of $5.1 million . (c) - Intersegment revenues for the Natural Gas Gathering and Processing segment totaled $244.2 million . Intersegment revenues for the Natural Gas Liquids and Natural Gas Pipelines segments were not material. Three Months Ended Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated NGL and condensate sales $ 1,991,562 $ (230,080 ) $ 1,761,482 Residue natural gas sales 185,534 (567 ) 184,967 Gathering, processing and exchange services revenue 147,974 — 147,974 Transportation and storage revenue 154,791 (2,594 ) 152,197 Other 18,406 (1,798 ) 16,608 Total revenues (a) $ 2,498,267 $ (235,039 ) $ 2,263,228 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (1,649,326 ) $ 234,798 $ (1,414,528 ) Operating costs $ (246,300 ) $ 1,165 $ (245,135 ) Depreciation and amortization $ (120,530 ) $ (900 ) $ (121,430 ) Equity in net earnings from investments $ 37,576 $ — $ 37,576 Capital expenditures $ 1,011,550 $ 7,624 $ 1,019,174 (a) - Noncustomer revenue for the three months ended September 30, 2019 , totaled $89.0 million related primarily to gains from commodity derivative contracts. Three Months Ended Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Total Segments ( Thousands of dollars ) NGL and condensate sales $ 501,163 $ 2,861,896 $ — $ 3,363,059 Residue natural gas sales 245,474 — 763 246,237 Gathering, processing and exchange services revenue 41,101 116,833 — 157,934 Transportation and storage revenue — 45,251 98,031 143,282 Other 3,517 2,308 6,400 12,225 Total revenues (c) 791,255 3,026,288 105,194 3,922,737 Cost of sales and fuel (exclusive of depreciation and operating costs) (542,463 ) (2,544,854 ) (2,384 ) (3,089,701 ) Operating costs (90,970 ) (101,126 ) (36,543 ) (228,639 ) Equity in net earnings from investments 74 16,450 22,789 39,313 Noncash compensation expense and other 1,703 2,268 1,050 5,021 Segment adjusted EBITDA $ 159,599 $ 399,026 $ 90,106 $ 648,731 Depreciation and amortization $ (49,223 ) $ (43,688 ) $ (13,625 ) $ (106,536 ) Capital expenditures $ 213,034 $ 444,780 $ 31,522 $ 689,336 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $316.0 million , of which $276.4 million related to revenues within the segment, and cost of sales and fuel of $132.7 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $65.9 million and cost of sales and fuel of $5.5 million . (c) - Intersegment revenues for the Natural Gas Gathering and Processing segment totaled $519.7 million . Intersegment revenues for the Natural Gas Liquids and Natural Gas Pipelines segments were not material. Three Months Ended Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated NGL and condensate sales $ 3,363,059 $ (526,398 ) $ 2,836,661 Residue natural gas sales 246,237 — 246,237 Gathering, processing and exchange services revenue 157,934 — 157,934 Transportation and storage revenue 143,282 (2,370 ) 140,912 Other 12,225 (79 ) 12,146 Total revenues (a) $ 3,922,737 $ (528,847 ) $ 3,393,890 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (3,089,701 ) $ 528,936 $ (2,560,765 ) Operating costs $ (228,639 ) $ (1,732 ) $ (230,371 ) Depreciation and amortization $ (106,536 ) $ (847 ) $ (107,383 ) Equity in net earnings from investments $ 39,313 $ — $ 39,313 Capital expenditures $ 689,336 $ 4,967 $ 694,303 (a) - Noncustomer revenue for the three months ended September 30, 2018 , totaled $(17.7) million related primarily to losses from derivatives on commodity contracts. Nine Months Ended Natural Gas Natural Gas Natural Gas Total Segments ( Thousands of dollars ) NGL and condensate sales $ 890,021 $ 5,826,297 $ — $ 6,716,318 Residue natural gas sales 725,672 — 1,242 726,914 Gathering, processing and exchange services revenue 126,073 309,571 — 435,644 Transportation and storage revenue — 141,384 317,555 458,939 Other 11,287 7,313 36,682 55,282 Total revenues (c) 1,753,053 6,284,565 355,479 8,393,097 Cost of sales and fuel (exclusive of depreciation and operating costs) (971,397 ) (4,914,452 ) (3,785 ) (5,889,634 ) Operating costs (271,236 ) (340,274 ) (113,043 ) (724,553 ) Equity in net earnings (loss) from investments (4,660 ) 49,406 70,429 115,175 Noncash compensation expense and other 8,399 12,618 1,931 22,948 Segment adjusted EBITDA $ 514,159 $ 1,091,863 $ 311,011 $ 1,917,033 Depreciation and amortization $ (162,014 ) $ (143,166 ) $ (42,653 ) $ (347,833 ) Total assets $ 6,546,417 $ 11,662,489 $ 2,083,773 $ 20,292,679 Capital expenditures $ 674,115 $ 1,969,138 $ 77,861 $ 2,721,114 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $1.0 billion , of which $853.0 million related to revenues within the segment, and cost of sales and fuel of $364.9 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $214.7 million and cost of sales and fuel of $14.4 million . (c) - Intersegment revenues for the Natural Gas Gathering and Processing segment totaled $897.9 million . Intersegment revenues for the Natural Gas Liquids and Natural Gas Pipelines segments were not material. Nine Months Ended Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated NGL and condensate sales $ 6,716,318 $ (878,958 ) $ 5,837,360 Residue natural gas sales 726,914 (567 ) 726,347 Gathering, processing and exchange services revenue 435,644 — 435,644 Transportation and storage revenue 458,939 (7,578 ) 451,361 Other 55,282 (5,233 ) 50,049 Total revenues (a) $ 8,393,097 $ (892,336 ) $ 7,500,761 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (5,889,634 ) $ 892,935 $ (4,996,699 ) Operating costs $ (724,553 ) $ 964 $ (723,589 ) Depreciation and amortization $ (347,833 ) $ (2,719 ) $ (350,552 ) Equity in net earnings from investments $ 115,175 $ — $ 115,175 Total assets $ 20,292,679 $ 1,043,228 $ 21,335,907 Capital expenditures $ 2,721,114 $ 18,224 $ 2,739,338 (a) - Noncustomer revenue for the nine months ended September 30, 2019 , totaled $129.9 million related primarily to gains from commodity derivative contracts. Nine Months Ended Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Total Segments ( Thousands of dollars ) NGL and condensate sales $ 1,362,159 $ 7,884,183 $ — $ 9,246,342 Residue natural gas sales 709,089 — 5,861 714,950 Gathering, processing and exchange services revenue 122,331 296,561 — 418,892 Transportation and storage revenue — 143,741 289,646 433,387 Other 6,596 8,202 19,390 34,188 Total revenues (c) 2,200,175 8,332,687 314,897 10,847,759 Cost of sales and fuel (exclusive of depreciation and operating costs) (1,478,044 ) (7,009,438 ) (10,475 ) (8,497,957 ) Operating costs (272,931 ) (289,328 ) (104,692 ) (666,951 ) Equity in net earnings from investments 948 49,456 65,666 116,070 Noncash compensation expense and other 6,868 9,789 3,701 20,358 Segment adjusted EBITDA $ 457,016 $ 1,093,166 $ 269,097 $ 1,819,279 Depreciation and amortization $ (145,120 ) $ (128,993 ) $ (41,320 ) $ (315,433 ) Total assets $ 5,811,140 $ 9,632,212 $ 2,109,897 $ 17,553,249 Capital expenditures $ 433,605 $ 786,635 $ 71,897 $ 1,292,137 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $910.3 million , of which $784.8 million related to revenues within the segment, and cost of sales and fuel of $379.5 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $198.4 million and cost of sales and fuel of $20.4 million . (c) - Intersegment revenues for the Natural Gas Gathering and Processing segment totaled $1.4 billion . Intersegment revenues for the Natural Gas Liquids and Natural Gas Pipelines segments were not material. Nine Months Ended Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated NGL and condensate sales $ 9,246,342 $ (1,383,864 ) $ 7,862,478 Residue natural gas sales 714,950 (778 ) 714,172 Gathering, processing and exchange services revenue 418,892 (21 ) 418,871 Transportation and storage revenue 433,387 (6,959 ) 426,428 Other 34,188 359 34,547 Total revenues (a) $ 10,847,759 $ (1,391,263 ) $ 9,456,496 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (8,497,957 ) $ 1,393,348 $ (7,104,609 ) Operating costs $ (666,951 ) $ (3,777 ) $ (670,728 ) Depreciation and amortization $ (315,433 ) $ (2,475 ) $ (317,908 ) Equity in net earnings from investments $ 116,070 $ — $ 116,070 Total assets $ 17,553,249 $ 358,065 $ 17,911,314 Capital expenditures $ 1,292,137 $ 17,518 $ 1,309,655 (a) - Noncustomer revenue for the nine months ended September 30, 2018 , totaled $(32.1) million related primarily to losses from derivatives on commodity contracts. Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 ( Thousands of dollars ) Reconciliation of net income to total segment adjusted EBITDA Net income $ 309,155 $ 313,916 $ 958,326 $ 862,144 Add: Interest expense, net of capitalized interest 129,577 121,910 362,490 351,131 Depreciation and amortization 121,430 107,383 350,552 317,908 Income taxes 97,365 102,983 274,234 266,285 Noncash compensation expense 9,757 5,829 20,412 27,195 Other corporate costs and noncash items (a) (20,711 ) (3,290 ) (48,981 ) (5,384 ) Total segment adjusted EBITDA $ 646,573 $ 648,731 $ 1,917,033 $ 1,819,279 (a) - Includes equity AFUDC related to our capital-growth projects.

SUPPLEMENTAL CONDENSED CONSOLID

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION (Notes)	9 Months Ended
	Sep. 30, 2019
Condensed Financial Information Disclosure [Abstract]
Supplemental Condensed Consolidating Financial Information	SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION ONEOK and ONEOK Partners are issuers of certain public debt securities. We, ONEOK Partners and the Intermediate Partnership guarantee 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 and Comprehensive Income Three Months Ended September 30, 2019 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 1,947.8 $ — $ 1,947.8 Services — — — 316.0 (0.6 ) 315.4 Total revenues — — — 2,263.8 (0.6 ) 2,263.2 Cost of sales and fuel (exclusive of items shown separately below) — — — 1,414.5 — 1,414.5 Operating expenses (0.7 ) — — 367.8 (0.6 ) 366.5 (Gain) loss on sale of assets — — 0.1 (0.1 ) — — Operating income 0.7 — (0.1 ) 481.6 — 482.2 Equity in net earnings from investments 470.2 476.1 476.2 29.1 (1,414.0 ) 37.6 Other income (expense), net 11.1 75.4 78.1 8.0 (156.2 ) 16.4 Interest expense, net (78.4 ) (78.1 ) (78.1 ) (51.2 ) 156.2 (129.6 ) Income before income taxes 403.6 473.4 476.1 467.5 (1,414.0 ) 406.6 Income taxes (94.4 ) — — (3.0 ) — (97.4 ) Net income 309.2 473.4 476.1 464.5 (1,414.0 ) 309.2 Less: Preferred stock dividends 0.3 — — — — 0.3 Net income available to common shareholders $ 308.9 $ 473.4 $ 476.1 $ 464.5 $ (1,414.0 ) $ 308.9 Net income $ 309.2 $ 473.4 $ 476.1 $ 464.5 $ (1,414.0 ) $ 309.2 Other comprehensive income (loss), net of tax (94.4 ) 12.4 7.9 5.0 (15.6 ) (84.7 ) Comprehensive income $ 214.8 $ 485.8 $ 484.0 $ 469.5 $ (1,429.6 ) $ 224.5 Three Months Ended September 30, 2018 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 3,083.6 $ — $ 3,083.6 Services — — — 310.8 (0.5 ) 310.3 Total revenues — — — 3,394.4 (0.5 ) 3,393.9 Cost of sales and fuel (exclusive of items shown separately below) — — — 2,560.8 — 2,560.8 Operating expenses 2.0 — — 336.3 (0.5 ) 337.8 Gain on sale of assets — — — (0.2 ) — (0.2 ) Operating income (2.0 ) — — 497.5 — 495.5 Equity in net earnings from investments 457.3 457.1 457.1 30.1 (1,362.3 ) 39.3 Other income (expense), net 9.3 80.3 80.3 (5.3 ) (160.6 ) 4.0 Interest expense, net (49.1 ) (80.3 ) (80.3 ) (72.8 ) 160.6 (121.9 ) Income before income taxes 415.5 457.1 457.1 449.5 (1,362.3 ) 416.9 Income taxes (102.3 ) — — (0.7 ) — (103.0 ) Net income 313.2 457.1 457.1 448.8 (1,362.3 ) 313.9 Less: Net income attributable to noncontrolling interests — — — 0.7 — 0.7 Net income attributable to ONEOK 313.2 457.1 457.1 448.1 (1,362.3 ) 313.2 Less: Preferred stock dividends 0.2 — — — — 0.2 Net income available to common shareholders $ 313.0 $ 457.1 $ 457.1 $ 448.1 $ (1,362.3 ) $ 313.0 Net income $ 313.2 $ 457.1 $ 457.1 $ 448.8 $ (1,362.3 ) $ 313.9 Other comprehensive income (loss), net of tax 23.4 (3.7 ) (8.1 ) (7.3 ) 16.2 20.5 Comprehensive income 336.6 453.4 449.0 441.5 (1,346.1 ) 334.4 Less: Comprehensive income attributable to noncontrolling interest — — — 0.7 — 0.7 Comprehensive income attributable to ONEOK $ 336.6 $ 453.4 $ 449.0 $ 440.8 $ (1,346.1 ) $ 333.7 Nine Months Ended September 30, 2019 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 6,567.6 $ — $ 6,567.6 Services — — — 934.8 (1.6 ) 933.2 Total revenues — — — 7,502.4 (1.6 ) 7,500.8 Cost of sales and fuel (exclusive of items shown separately below) — — — 4,996.7 — 4,996.7 Operating expenses (0.7 ) — — 1,076.5 (1.6 ) 1,074.2 Loss on sale of assets — — 2.7 0.2 — 2.9 Operating income 0.7 — (2.7 ) 1,429.0 — 1,427.0 Equity in net earnings from investments 1,392.9 1,405.6 1,408.3 87.1 (4,178.7 ) 115.2 Other income (expense), net 26.3 232.8 235.5 29.3 (471.0 ) 52.9 Interest expense, net (198.1 ) (235.5 ) (235.5 ) (164.4 ) 471.0 (362.5 ) Income before income taxes 1,221.8 1,402.9 1,405.6 1,381.0 (4,178.7 ) 1,232.6 Income taxes (263.5 ) — — (10.8 ) — (274.3 ) Net income 958.3 1,402.9 1,405.6 1,370.2 (4,178.7 ) 958.3 Less: Preferred stock dividends 0.8 — — — — 0.8 Net income available to common shareholders $ 957.5 $ 1,402.9 $ 1,405.6 $ 1,370.2 $ (4,178.7 ) $ 957.5 Net income $ 958.3 $ 1,402.9 $ 1,405.6 $ 1,370.2 $ (4,178.7 ) $ 958.3 Other comprehensive income (loss), net of tax (226.0 ) (9.0 ) (22.5 ) (20.6 ) 45.3 (232.8 ) Comprehensive income $ 732.3 $ 1,393.9 $ 1,383.1 $ 1,349.6 $ (4,133.4 ) $ 725.5 Nine Months Ended September 30, 2018 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 8,578.9 $ — $ 8,578.9 Services — — — 879.1 (1.5 ) 877.6 Total revenues — — — 9,458.0 (1.5 ) 9,456.5 Cost of sales and fuel (exclusive of items shown separately below) — — — 7,104.6 — 7,104.6 Operating expenses 3.3 — — 986.8 (1.5 ) 988.6 Gain on sale of assets — — — (0.3 ) — (0.3 ) Operating income (3.3 ) — — 1,366.9 — 1,363.6 Equity in net earnings from investments 1,226.6 1,231.2 1,231.2 86.2 (3,659.1 ) 116.1 Other income (expense), net 23.1 234.9 234.9 (23.3 ) (469.8 ) (0.2 ) Interest expense, net (129.2 ) (234.9 ) (234.9 ) (221.9 ) 469.8 (351.1 ) Income before income taxes 1,117.2 1,231.2 1,231.2 1,207.9 (3,659.1 ) 1,128.4 Income taxes (258.4 ) — — (7.9 ) — (266.3 ) Net income 858.8 1,231.2 1,231.2 1,200.0 (3,659.1 ) 862.1 Less: Net income attributable to noncontrolling interests — — — 3.3 — 3.3 Net income attributable to ONEOK 858.8 1,231.2 1,231.2 1,196.7 (3,659.1 ) 858.8 Less: Preferred stock dividends 0.8 — — — — 0.8 Net income available to common shareholders $ 858.0 $ 1,231.2 $ 1,231.2 $ 1,196.7 $ (3,659.1 ) $ 858.0 Net income $ 858.8 $ 1,231.2 $ 1,231.2 $ 1,200.0 $ (3,659.1 ) $ 862.1 Other comprehensive income (loss), net of tax 65.6 4.0 (6.9 ) (8.0 ) 13.8 68.5 Comprehensive income 924.4 1,235.2 1,224.3 1,192.0 (3,645.3 ) 930.6 Less: Comprehensive income attributable to noncontrolling interest — — — 3.3 — 3.3 Comprehensive income attributable to ONEOK $ 924.4 $ 1,235.2 $ 1,224.3 $ 1,188.7 $ (3,645.3 ) $ 927.3 Condensed Consolidating Balance Sheets September 30, 2019 ( 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 $ 673.3 $ — $ — $ — $ — $ 673.3 Accounts receivable, net — — — 718.7 — 718.7 Materials and supplies — — — 192.9 — 192.9 Natural gas and NGLs in storage — — — 283.5 — 283.5 Other current assets 12.3 — — 86.8 — 99.1 Total current assets 685.6 — — 1,281.9 — 1,967.5 Property, plant and equipment Property, plant and equipment 160.0 — — 20,788.3 — 20,948.3 Accumulated depreciation and amortization 97.6 — — 3,487.8 — 3,585.4 Net property, plant and equipment 62.4 — — 17,300.5 — 17,362.9 Investments and other assets Investments 6,554.5 3,932.2 10,986.9 770.6 (21,373.7 ) 870.5 Intercompany receivable 8,099.1 6,897.7 — — (14,996.8 ) — Other assets 134.8 — — 1,001.1 (0.9 ) 1,135.0 Total investments and other assets 14,788.4 10,829.9 10,986.9 1,771.7 (36,371.4 ) 2,005.5 Total assets $ 15,536.4 $ 10,829.9 $ 10,986.9 $ 20,354.1 $ (36,371.4 ) $ 21,335.9 Liabilities and equity Current liabilities Current maturities of long-term debt $ — $ — $ — $ 7.7 $ — $ 7.7 Accounts payable 9.5 — — 1,120.3 — 1,129.8 Other current liabilities 96.4 63.5 — 269.7 — 429.6 Total current liabilities 105.9 63.5 — 1,397.7 — 1,567.1 Intercompany payable — — 7,054.7 7,942.1 (14,996.8 ) — Long-term debt, excluding current maturities 8,419.6 4,044.3 — 15.6 — 12,479.5 Deferred credits and other liabilities Deferred income taxes 297.9 — — 121.7 (0.9 ) 418.7 Other deferred credits 494.1 — — 157.6 — 651.7 Total deferred credits and other liabilities 792.0 — — 279.3 (0.9 ) 1,070.4 Commitments and contingencies Equity 6,218.9 6,722.1 3,932.2 10,719.4 (21,373.7 ) 6,218.9 Total liabilities and equity $ 15,536.4 $ 10,829.9 $ 10,986.9 $ 20,354.1 $ (36,371.4 ) $ 21,335.9 December 31, 2018 ( 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 $ 12.0 $ — $ — $ — $ — $ 12.0 Accounts receivable, net — — — 819.0 — 819.0 Materials and supplies — — — 141.2 — 141.2 Natural gas and NGLs in storage — — — 296.7 — 296.7 Other current assets 29.1 — — 100.6 — 129.7 Total current assets 41.1 — — 1,357.5 — 1,398.6 Property, plant and equipment Property, plant and equipment 145.5 — — 17,885.5 — 18,031.0 Accumulated depreciation and amortization 92.0 — — 3,172.3 — 3,264.3 Net property, plant and equipment 53.5 — — 14,713.2 — 14,766.7 Investments and other assets Investments 6,153.5 3,548.1 9,721.6 791.1 (19,245.1 ) 969.2 Intercompany receivable 5,308.6 7,701.5 1,528.0 — (14,538.1 ) — Other assets 115.9 — — 982.3 (1.0 ) 1,097.2 Total investments and other assets 11,578.0 11,249.6 11,249.6 1,773.4 (33,784.2 ) 2,066.4 Total assets $ 11,672.6 $ 11,249.6 $ 11,249.6 $ 17,844.1 $ (33,784.2 ) $ 18,231.7 Liabilities and equity Current liabilities Current maturities of long-term debt $ — $ 500.0 $ — $ 7.7 $ — $ 507.7 Accounts payable 31.3 — — 1,085.0 — 1,116.3 Other current liabilities 123.2 81.0 — 280.2 — 484.4 Total current liabilities 154.5 581.0 — 1,372.9 — 2,108.4 Intercompany payable — — 7,701.5 6,836.6 (14,538.1 ) — Long-term debt, excluding current maturities 4,510.7 4,341.4 — 21.2 — 8,873.3 Deferred credits and other liabilities Deferred income taxes 112.3 — — 108.4 (1.0 ) 219.7 Other deferred credits 315.6 — — 135.2 — 450.8 Total deferred credits and other liabilities 427.9 — — 243.6 (1.0 ) 670.5 Commitments and contingencies Equity 6,579.5 6,327.2 3,548.1 9,369.8 (19,245.1 ) 6,579.5 Total liabilities and equity $ 11,672.6 $ 11,249.6 $ 11,249.6 $ 17,844.1 $ (33,784.2 ) $ 18,231.7 Condensed Consolidating Statements of Cash Flows Nine Months Ended September 30, 2019 ( 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 $ 761.9 $ 897.3 $ 50.6 $ 1,615.0 $ (1,998.0 ) $ 1,326.8 Investing activities Capital expenditures (17.8 ) — — (2,721.5 ) — (2,739.3 ) Contributions to unconsolidated affiliates — — — (3.3 ) — (3.3 ) Other investing activities — — 72.5 22.2 — 94.7 Cash used in investing activities (17.8 ) — 72.5 (2,702.6 ) — (2,647.9 ) Financing activities Dividends paid (1,079.4 ) (999.0 ) (999.0 ) — 1,998.0 (1,079.4 ) Intercompany borrowings (advances), net (2,874.4 ) 904.1 875.9 1,094.4 — — Issuance of long-term debt, net of discounts 4,185.4 — — — — 4,185.4 Repayment of long-term debt (250.0 ) (799.7 ) — (5.7 ) — (1,055.4 ) Issuance of common stock 19.3 — — — — 19.3 Other (83.7 ) (2.7 ) — (1.1 ) — (87.5 ) Cash provided by financing activities (82.8 ) (897.3 ) (123.1 ) 1,087.6 1,998.0 1,982.4 Change in cash and cash equivalents 661.3 — — — — 661.3 Cash and cash equivalents at beginning of period 12.0 — — — — 12.0 Cash and cash equivalents at end of period $ 673.3 $ — $ — $ — $ — $ 673.3 Nine Months Ended September 30, 2018 ( 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 $ 964.4 $ 993.8 $ 48.9 $ 1,507.4 $ (1,998.0 ) $ 1,516.5 Investing activities Capital expenditures (15.0 ) — — (1,294.7 ) — (1,309.7 ) Contributions to unconsolidated affiliates — — (0.5 ) (0.3 ) — (0.8 ) Other investing activities — — 10.8 9.9 — 20.7 Cash used in investing activities (15.0 ) — 10.3 (1,285.1 ) — (1,289.8 ) Financing activities Dividends paid (983.1 ) (999.0 ) (999.0 ) — 1,998.0 (983.1 ) Distributions to noncontrolling interests — — — (3.5 ) — (3.5 ) Intercompany borrowings (advances), net (1,640.5 ) 930.2 939.8 (229.5 ) — — Borrowing (repayment) of short-term borrowings, net (494.7 ) — — — — (494.7 ) Issuance of long-term debt, net of discounts 1,245.8 — — — — 1,245.8 Repayment of long-term debt — (925.0 ) — (5.7 ) — (930.7 ) Issuance of common stock 1,195.1 — — — — 1,195.1 Acquisition of noncontrolling interests (195.0 ) — — — — (195.0 ) Other, net (29.7 ) — — 16.4 — (13.3 ) Cash used in financing activities (902.1 ) (993.8 ) (59.2 ) (222.3 ) 1,998.0 (179.4 ) Change in cash and cash equivalents 47.3 — — — — 47.3 Cash and cash equivalents at beginning of period 37.2 — — — — 37.2 Cash and cash equivalents at end of period $ 84.5 $ — $ — $ — $ — $ 84.5

SUMMARY OF SIGNIFICANT ACCOUN_2

SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	9 Months Ended
SUMMARY OF SIGNIFICANT ACCOUNTING POLICIES (Policies)	Sep. 30, 2019
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 2018 year-end Consolidated Balance Sheet data was derived from our audited Consolidated Financial Statements but does not include all disclosures required by GAAP. Certain reclassifications and revisions have been made in the prior-year Consolidated Financial Statements to conform to the current year presentation. See Note E for additional information. These unaudited Consolidated Financial Statements should be read in conjunction with our audited Consolidated Financial Statements in our Annual Report.
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 or in our Annual Report were assessed and determined to be either not applicable or clarifications of ASUs listed below. Except as discussed below or in our Annual Report, there have been no new accounting pronouncements that have become effective or have been issued that are of significance or potential significance to us. The following table provides a brief description of recently adopted 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 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 adopted this standard on January 1, 2019, using the modified retrospective method and the optional transition method to record the adoption impact through a cumulative adjustment to equity. We recorded an immaterial cumulative effect for the adoption of the new standard and recorded $17.5 million of right-of-use assets and $17.4 million of lease liabilities related to operating leases that were not previously recorded on our Consolidated Balance Sheets. Our finance lease assets and liabilities of $28.1 million and $28.0 million, respectively, did not change as a result of adopting this standard. See Note K for additional disclosures. ASU 2018-07, “Compensation - Stock Compensation (Topic 718): Improvements to Nonemployee Share-Based Payment Accounting” The standard aligns the measurement and classification guidance for share-based payments to nonemployees with the guidance for share-based payments to employees, with certain exceptions. First quarter 2019 The impact of adopting this standard was not material.

FAIR VALUE MEASUREMENTS FAIR VA

FAIR VALUE MEASUREMENTS FAIR VALUE MEASUREMENTS (Policies)	9 Months Ended
FAIR VALUE MEASUREMENTS FAIR VALUE MEASUREMENTS (Policies)	Sep. 30, 2019
Fair Value Accounting Policy [Abstract]
Fair Value of Financial Instruments, Policy [Policy Text Block]	Determining Fair Value - For our fair value measurements, we utilize market prices, third-party pricing services, present value methods and standard option valuation models to determine the price we would receive from the sale of an asset or the transfer of a liability in an orderly transaction at the measurement date. 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 may utilize modeling techniques using NYMEX-settled pricing data and implied forward LIBOR curves. Inputs into our fair value estimates include commodity-exchange prices, data obtained from third-party pricing services, LIBOR and other liquid money-market instrument rates. Our financial commodity derivatives are generally settled through a NYMEX or Intercontinental Exchange (ICE) clearing broker account with daily margin requirements. We validate our valuation inputs with third-party information and settlement prices from other sources, where available. 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 the implied forward LIBOR yield curve. The fair value of our forward-starting interest-rate swaps is determined using financial models that incorporate the implied forward LIBOR yield curve for the same period as the future interest-rate swap settlements. We consider current market data in evaluating counterparties’, as well as our own, nonperformance risk, net of collateral, by using counterparty-specific bond yields. 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 materially from our estimates. 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. These balances are composed predominantly of exchange-traded derivative contracts for natural gas and crude oil. • Level 2 - fair value measurements are based on significant observable pricing inputs, including quoted prices for similar assets and liabilities in active markets and inputs from third-party pricing services supported with corroborative evidence. These balances are composed of over-the-counter interest-rate derivatives. • 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 and third-party pricing services. These balances are composed predominantly of exchange-cleared and over-the-counter derivatives for natural gas basis and NGLs. Our commodity derivatives are generally valued using forward quotes provided by third-party pricing services that are validated with other market data. We believe any measurement uncertainty at September 30, 2019 , is immaterial as our Level 3 fair value measurements are based on unadjusted pricing information from broker quotes and third-party pricing services. We do not believe that our Level 3 fair value estimates have a material impact on our results of operations, as our derivatives are accounted for as hedges. 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.

LEASES (Policies)

LEASES (Policies)	9 Months Ended
LEASES (Policies)	Sep. 30, 2019
Leases [Abstract]
Lessee, Leases [Policy Text Block]	Our weighted-average discount rates represent the rate implicit in the lease or our incremental borrowing rate for a term equal to the remaining term of the lease. Leases - We lease certain buildings, warehouses, office space, land and equipment, including pipeline equipment, rail cars and information technology equipment. Our lease payments are generally straight-line and the exercise of lease renewal options, which vary in term, is at our sole discretion. We include renewal periods in a lease term if we are reasonably certain to exercise available renewal options. Our lease agreements do not include any residual value guarantees or material restrictive covenants.

REVENUE REVENUE (Policies)

REVENUE REVENUE (Policies)	9 Months Ended
REVENUE REVENUE (Policies)	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customer [Policy Text Block]	Accounting Policies

SEGMENTS SEGMENTS (Policies)

SEGMENTS SEGMENTS (Policies)	9 Months Ended
SEGMENTS SEGMENTS (Policies)	Sep. 30, 2019
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.

FAIR VALUE MEASUREMENTS (Tables

FAIR VALUE MEASUREMENTS (Tables)	9 Months Ended
FAIR VALUE MEASUREMENTS (Tables)	Sep. 30, 2019
Fair Value Disclosures [Abstract]
Recurring Fair Value Measurements	The following tables set forth our recurring fair value measurements for the periods indicated: September 30, 2019 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 12,267 $ — $ 68,049 $ 80,316 $ (40,413 ) $ 39,903 Physical contracts — — 579 579 — 579 Total derivative assets $ 12,267 $ — $ 68,628 $ 80,895 $ (40,413 ) $ 40,482 Derivative liabilities Commodity contracts Financial contracts $ — $ — $ (40,413 ) $ (40,413 ) $ 40,413 $ — Interest-rate contracts — (276,865 ) — (276,865 ) — (276,865 ) Total derivative liabilities $ — $ (276,865 ) $ (40,413 ) $ (317,278 ) $ 40,413 $ (276,865 ) (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, 2019 , we held no cash and posted $1.9 million of cash with various counterparties, which is included in other current assets in our Consolidated Balance Sheet. December 31, 2018 Level 1 Level 2 Level 3 Total - Gross Netting (a) Total - Net ( Thousands of dollars ) Derivative assets Commodity contracts Financial contracts $ 10,812 $ — $ 69,165 $ 79,977 $ (32,739 ) $ 47,238 Physical contracts — — 1,142 1,142 — 1,142 Interest-rate contracts — 19,005 — 19,005 — 19,005 Total derivative assets $ 10,812 $ 19,005 $ 70,307 $ 100,124 $ (32,739 ) $ 67,385 Derivative liabilities Commodity contracts Financial contracts $ (2,916 ) $ — $ (29,823 ) $ (32,739 ) $ 32,739 $ — Interest-rate contracts — (99,260 ) — (99,260 ) — (99,260 ) Total derivative liabilities $ (2,916 ) $ (99,260 ) $ (29,823 ) $ (131,999 ) $ 32,739 $ (99,260 ) (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, 2018 , we held no cash and posted $0.8 million of cash with various counterparties, which is included in other current assets in our Consolidated Balance Sheet.
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) 2019 2018 2019 2018 ( Thousands of dollars ) Net assets (liabilities) at beginning of period $ 19,274 $ (23,501 ) $ 40,484 $ (32,838 ) Total changes in fair value: Included in net income (a) — (22 ) — (122 ) Included in other comprehensive income (loss) (b) 8,941 (7,554 ) (12,269 ) 1,883 Net assets (liabilities) at end of period $ 28,215 $ (31,077 ) $ 28,215 $ (31,077 ) (a) - Included in commodity sales revenues/cost of sales and fuel in our Consolidated Statements of Income.

RISK MANAGEMENT AND HEDGING A_2

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES (Tables)	9 Months Ended
	Sep. 30, 2019
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Fair Value of Derivatives	The following table sets forth the fair values of our derivative instruments presented on a gross basis for the periods indicated: September 30, 2019 December 31, 2018 Location in our Consolidated Balance Sheets Assets (Liabilities) Assets (Liabilities) ( Thousands of dollars ) Derivatives designated as hedging instruments Commodity contracts (a) Financial contracts Other current assets $ 72,995 $ (36,186 ) $ 78,891 $ (31,793 ) Other assets 7,321 (4,227 ) 1,086 (946 ) Physical contracts Other current assets 579 — 1,142 — Interest-rate contracts Other current assets/other current liabilities — (14,672 ) 19,005 (15,012 ) Other deferred credits — (262,193 ) — (84,248 ) Total derivatives designated as hedging instruments $ 80,895 $ (317,278 ) $ 100,124 $ (131,999 ) (a) - Derivative assets and liabilities are presented in our Consolidated Balance Sheets on a net basis when a legally enforceable master-netting arrangement exists between the counterparty to a derivative contract and us.
Notional Amounts of Derivative Instruments	The following table sets forth the notional quantities for derivative instruments held for the periods indicated: September 30, 2019 December 31, 2018 Contract Type Purchased/ Payor Sold/ Receiver Purchased/ Payor Sold/ Receiver Derivatives designated as hedging instruments: Cash flow hedges Fixed price - Natural gas ( Bcf ) Futures and swaps — (39.6 ) — (29.9 ) - Crude oil and NGLs ( MMBbl ) Futures, forwards, swaps and options 9.2 (20.1 ) 6.5 (13.8 ) Basis - Natural gas ( Bcf ) Futures and swaps — (39.6 ) — (29.9 ) Interest-rate contracts ( Billions of dollars ) Swaps $ 3.1 $ — $ 4.3 $ —
Schedule of Cash Flow Hedging Instruments Effect on Comprehensive Income (Loss)	The following table sets forth the unrealized change in fair value of cash flow hedges 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, 2019 2018 2019 2018 ( Thousands of dollars ) Commodity contracts $ 32,169 $ (30,783 ) $ 43,877 $ (56,246 ) Interest-rate contracts (128,041 ) 26,203 (303,351 ) 70,179 Total unrealized change in fair value of cash flow hedges in other comprehensive income (loss) $ (95,872 ) $ (4,580 ) $ (259,474 ) $ 13,933
Schedule of Cash Flow Hedging Instruments Effect on Income	The following table sets forth the effect of cash flow hedges on net income for the periods indicated: Derivatives in Cash Flow Hedging Relationships Location of Gain (Loss) Reclassified from Accumulated Other Comprehensive Loss into Net Income Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 ( Thousands of dollars ) Commodity contracts Commodity sales revenues/ cost of sales and fuel $ 18,528 $ (20,630 ) $ 52,624 $ (42,430 ) Interest-rate contracts Interest expense (6,903 ) (4,383 ) (14,222 ) (13,929 ) Total change in fair value of cash flow hedges reclassified from accumulated other comprehensive loss into net income $ 11,625 $ (25,013 ) $ 38,402 $ (56,359 )

DEBT DEBT (Tables)

DEBT DEBT (Tables)	9 Months Ended
DEBT DEBT (Tables)	Sep. 30, 2019
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 ) Commercial paper outstanding $ — $ — Senior unsecured obligations: $500,000 at 8.625% due March 2019 — 500,000 $300,000 at 3.8% due March 2020 — 300,000 $1,500,000 term loan, variable rate, due November 2021 1,250,000 550,000 $700,000 at 4.25% due February 2022 547,397 547,397 $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 7.5% due September 2023 500,000 500,000 $500,000 at 2.75% due September 2024 500,000 — $500,000 at 4.9% due March 2025 500,000 500,000 $500,000 at 4.0% due July 2027 500,000 500,000 $800,000 at 4.55% due July 2028 800,000 800,000 $100,000 at 6.875% due September 2028 100,000 100,000 $700,000 at 4.35% due March 2029 700,000 — $750,000 at 3.4% due September 2029 750,000 — $400,000 at 6.0% due June 2035 400,000 400,000 $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 $700,000 at 4.95% due July 2047 700,000 700,000 $1,000,000 at 5.2% due July 2048 1,000,000 450,000 $750,000 at 4.45% due September 2049 750,000 — Guardian Pipeline Weighted average 7.85% due December 2022 23,220 28,957 Total debt 12,595,617 9,451,354 Unamortized portion of terminated swaps 15,461 16,750 Unamortized debt issuance costs and discounts (123,976 ) (87,120 ) Current maturities of long-term debt (7,650 ) (507,650 ) Long-term debt $ 12,479,452 $ 8,873,334

ACCUMULATED OTHER COMPREHENSI_2

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ACCUMULATED OTHER COMPREHENSIVE INCOME (Tables)	9 Months Ended
	Sep. 30, 2019
Accumulated Other Comprehensive Income (Loss)	The following table sets forth the balance in accumulated other comprehensive loss for the period indicated: Risk- Management Assets/Liabilities (a) Retirement and Other Postretirement Benefit Plan Obligations (a) (b) Risk- Management Assets/Liabilities of Unconsolidated Affiliates (a) Accumulated Other Comprehensive Loss (a) ( Thousands of dollars ) January 1, 2019 $ (64,660 ) $ (121,785 ) $ (1,794 ) $ (188,239 ) Other comprehensive loss before reclassifications (199,795 ) (63 ) (10,567 ) (210,425 ) Amounts reclassified to net income (29,748 ) 7,334 (26 ) (22,440 ) Other comprehensive income (loss) (229,543 ) 7,271 (10,593 ) (232,865 ) September 30, 2019 $ (294,203 ) $ (114,514 ) $ (12,387 ) $ (421,104 ) (a) - All amounts are presented net of tax. (b) - Includes amounts related to supplemental executive retirement plan.
Reclassification out of Accumulated Other Comprehensive Income (Loss)	The following table sets forth the effect of reclassifications from accumulated other comprehensive loss to net 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, 2019 2018 2019 2018 ( Thousands of dollars ) Risk-management assets/liabilities Commodity contracts $ 18,528 $ (20,630 ) $ 52,624 $ (42,430 ) Commodity sales revenues/cost of sales and fuel Interest-rate contracts (6,903 ) (4,383 ) (14,222 ) (13,929 ) Interest expense 11,625 (25,013 ) 38,402 (56,359 ) Income before income taxes (2,673 ) 5,752 (8,654 ) 12,962 Income taxes $ 8,952 $ (19,261 ) $ 29,748 $ (43,397 ) Net income Retirement and other postretirement benefit plan obligations (a) Amortization of net loss $ (3,232 ) $ (4,592 ) $ (9,696 ) $ (13,776 ) Other income (expense) Amortization of unrecognized prior service credit 57 415 171 1,245 Other income (expense) (3,175 ) (4,177 ) (9,525 ) (12,531 ) Income before income taxes 731 961 2,191 2,882 Income taxes $ (2,444 ) $ (3,216 ) $ (7,334 ) $ (9,649 ) Net income Risk-management assets/liabilities of unconsolidated affiliates Interest-rate contracts $ (59 ) $ 52 $ 34 $ 71 Equity in net earnings from investments 13 (12 ) (8 ) (16 ) Income taxes $ (46 ) $ 40 $ 26 $ 55 Net income Total reclassifications for the period $ 6,462 $ (22,437 ) $ 22,440 $ (52,991 ) Net income (a) - These components of accumulated other comprehensive loss are included in the computation of net periodic benefit cost. See Note H for additional detail of our net periodic benefit cost.
Schedule of Accumulated Other Comprehensive Income (Loss) for Risk-Management Assets/Liabilities [Table Text Block]	The following table sets forth information about the balance of accumulated other comprehensive loss at September 30, 2019 , representing unrealized gains (losses) related to risk-management assets and liabilities: Risk- Management Assets/Liabilities (a) ( Thousands of dollars ) Commodity derivative instruments expected to be realized within the next 27 months (b) $ 30,258 Settled interest-rate swaps to be recognized over the life of the long-term, fixed-rate debt (c) (111,275 ) Interest-rate swaps with future settlement dates expected to be amortized over the life of long-term debt (213,186 ) Accumulated other comprehensive loss at September 30, 2019 $ (294,203 ) (a) - All amounts are presented net of tax. (b) - Based on September 30, 2019 , commodity prices, we will realize $27.9 million in net gains, net of tax, over the next 12 months and $2.4 million in net gains, net of tax, thereafter. (c) - Losses of $19.7 million , net of tax, will be reclassified into earnings during the next 12 months as the hedged items affect earnings.

EARNINGS PER SHARE EARNINGS P_2

EARNINGS PER SHARE EARNINGS PER SHARE (Tables)	9 Months Ended
EARNINGS PER SHARE EARNINGS PER SHARE (Tables)	Sep. 30, 2019
Earnings Per Share [Abstract]
Earnings Per Share	The following tables set forth the computation of basic and diluted EPS for the periods indicated: Three Months Ended September 30, 2019 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Net income available for common stock $ 308,880 413,816 $ 0.75 Diluted EPS Effect of dilutive securities — 1,762 Net income available for common stock and common stock equivalents $ 308,880 415,578 $ 0.74 Three Months Ended September 30, 2018 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Net income attributable to ONEOK available for common stock $ 312,984 412,117 $ 0.76 Diluted EPS Effect of dilutive securities — 2,730 Net income attributable to ONEOK available for common stock and common stock equivalents $ 312,984 414,847 $ 0.75 Nine Months Ended September 30, 2019 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Net income available for common stock $ 957,501 413,443 $ 2.32 Diluted EPS Effect of dilutive securities — 1,834 Net income available for common stock and common stock equivalents $ 957,501 415,277 $ 2.31 Nine Months Ended September 30, 2018 Income Shares Per Share Amount ( Thousands, except per share amounts ) Basic EPS Net income attributable to ONEOK available for common stock $ 857,990 411,400 $ 2.09 Diluted EPS Effect of dilutive securities — 2,635 Net income attributable to ONEOK available for common stock and common stock equivalents $ 857,990 414,035 $ 2.07

EMPLOYEE BENEFIT PLANS EMPLOY_2

EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS (Tables)	9 Months Ended
EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS (Tables)	Sep. 30, 2019
Defined Benefit Plan [Abstract]
Components of net periodic benefit cost for retirement and postretirement benefit plans	The following tables set forth the components of net periodic benefit cost (income) for our retirement and other postretirement benefit plans for the periods indicated: Retirement Benefits Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 ( Thousands of dollars ) Components of net periodic benefit cost Service cost $ 1,954 $ 1,832 $ 5,862 $ 5,496 Interest cost 5,126 4,408 15,378 13,224 Expected return on plan assets (5,892 ) (5,969 ) (17,676 ) (17,907 ) Amortization of net loss 3,158 4,258 9,474 12,774 Net periodic benefit cost $ 4,346 $ 4,529 $ 13,038 $ 13,587 Other Postretirement Benefits Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 ( Thousands of dollars ) Components of net periodic benefit cost Service cost $ 117 $ 211 $ 351 $ 633 Interest cost 509 527 1,527 1,581 Expected return on plan assets (570 ) (672 ) (1,710 ) (2,016 ) Amortization of prior service credit (57 ) (415 ) (171 ) (1,245 ) Amortization of net loss 74 334 222 1,002 Net periodic benefit cost (income) $ 73 $ (15 ) $ 219 $ (45 )

UNCONSOLIDATED AFFILIATES (Tabl

UNCONSOLIDATED AFFILIATES (Tables)	9 Months Ended
UNCONSOLIDATED AFFILIATES (Tables)	Sep. 30, 2019
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 (loss) from investments for the periods indicated: Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 ( Thousands of dollars ) Northern Border Pipeline $ 16,102 $ 16,486 $ 50,593 $ 48,863 Overland Pass Pipeline 15,481 16,081 48,340 48,714 Roadrunner 7,421 6,303 19,836 16,803 Other (1,428 ) 443 (3,594 ) 1,690 Equity in net earnings from investments $ 37,576 $ 39,313 $ 115,175 $ 116,070
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, 2019 2018 2019 2018 ( Thousands of dollars ) Income Statement Revenues $ 151,210 $ 160,962 $ 471,461 $ 471,641 Operating expenses $ 69,783 $ 69,004 $ 217,287 $ 205,525 Net income $ 74,341 $ 85,361 $ 234,154 $ 247,754 Distributions paid to us (a) $ 44,357 $ 47,197 $ 203,347 $ 145,437 (a) - As determined by the Northern Border Pipeline Management Committee, we received an additional distribution of $50.0 million

LEASES (Tables)

LEASES (Tables)	9 Months Ended
LEASES (Tables)	Sep. 30, 2019
Leases [Abstract]
Lessee, Operating Lease, Liability, Maturity [Table Text Block]	The following table sets forth the maturity of our lease liabilities as of September 30, 2019 : Finance Lease Operating Leases ( Millions of dollars ) Remainder of 2019 $ 1.1 $ 1.3 2020 4.5 2.4 2021 4.5 2.0 2022 4.5 2.0 2023 4.5 1.9 2024 and beyond 21.6 11.1 Total lease payments 40.7 20.7 Less: Interest 14.0 4.3 Present value of lease liabilities $ 26.7 $ 16.4
Lease Assets and Liabilities Included in the Consolidated Balance Sheet[Table Text Block]	The following table sets forth information about our supplemental cash flows: Nine Months Ended September 30, 2019 ( Thousands of dollars ) Cash paid for amounts included in the measurement of lease liabilities Operating cash flows for operating leases $ 4,972 Financing cash flows for finance lease $ 1,307 Right-of-use assets obtained in exchange for operating lease liabilities (noncash) $ 3,663 The following table sets forth information about our lease assets and liabilities included in our Consolidated Balance Sheet for the period indicated: Leases Location in our Consolidated Balance Sheet September 30, 2019 ( Thousands of dollars ) Assets Operating leases Other assets $ 16,176 Finance lease Property, plant and equipment 28,286 Finance lease Accumulated depreciation (1,037 ) Total leased assets $ 43,425 Liabilities Current Operating leases Other current liabilities $ 2,624 Finance lease Finance lease liability 1,901 Noncurrent Operating leases Other deferred credits 13,790 Finance lease Finance lease liability 24,801 Total lease liabilities $ 43,116
Lease, Cost [Table Text Block]	The following table sets forth information about our leases for the periods indicated: Three Months Ended September 30, 2019 Nine Months Ended September 30, 2019 At September 30, 2019 Location in our Consolidated Statement of Income Lease Cost Weighted-Average Remaining Lease Term Weighted-Average Discount Rate (a) ( Thousands of dollars ) ( Years ) Operating leases Operations and maintenance $ 1,751 $ 5,402 10.1 4.58% Finance lease 9.1 10.00% Amortization of lease assets Depreciation and amortization 283 849 Interest on lease liabilities Interest expense 675 2,058 Total lease cost $ 2,709 $ 8,309 (a) - Our weighted-average discount rates represent the rate implicit in the lease or our incremental borrowing rate for a term equal to the remaining term of the lease.
Finance Lease, Liability, Maturity [Table Text Block]	The following table sets forth the maturity of our lease liabilities as of September 30, 2019 : Finance Lease Operating Leases ( Millions of dollars ) Remainder of 2019 $ 1.1 $ 1.3 2020 4.5 2.4 2021 4.5 2.0 2022 4.5 2.0 2023 4.5 1.9 2024 and beyond 21.6 11.1 Total lease payments 40.7 20.7 Less: Interest 14.0 4.3 Present value of lease liabilities $ 26.7 $ 16.4

REVENUE REVENUE (Tables)

REVENUE REVENUE (Tables)	9 Months Ended
REVENUE REVENUE (Tables)	Sep. 30, 2019
Revenue from Contract with Customer [Abstract]
Contract with Customer, Asset and Liability [Table Text Block]	The following tables set forth the balances in contract assets and contract liabilities for the periods indicated: Contract Assets ( Millions of dollars ) Balance at December 31, 2018 (a) $ 6.2 Amounts invoiced in excess of revenue recognized (0.9 ) Net additions 0.8 Balance at September 30, 2019 (b) $ 6.1 (a) - Contract assets of $1.7 million and $4.5 million are included in other current assets and other assets, respectively, in our Consolidated Balance Sheets. (b) - Contract assets of $2.4 million and $3.7 million are included in other current assets and other assets, respectively, in our Consolidated Balance Sheets. Contract Liabilities ( Millions of dollars ) Balance at December 31, 2018 (a) $ 31.7 Revenue recognized included in beginning balance (15.2 ) Net additions 28.9 Balance at September 30, 2019 (b) $ 45.4 (a) - Contract liabilities of $15.6 million and $16.1 million are included in other current liabilities and other deferred credits, respectively, in our Consolidated Balance Sheets. (b) - Contract liabilities of $25.2 million and $20.2 million are included in other current liabilities and other deferred credits, respectively, in our Consolidated Balance Sheets.
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Table Text Block]	The following table presents aggregate value allocated to unsatisfied performance obligations as of September 30, 2019 , and the amounts we expect to recognize in revenue in future periods, related primarily to firm transportation and storage contracts with remaining contract terms ranging from one month to 24 years: Expected Period of Recognition in Revenue ( Millions of dollars ) Remainder of 2019 $ 101.5 2020 335.6 2021 286.3 2022 228.3 2023 and beyond 952.5 Total estimated transaction price allocated to unsatisfied performance obligations $ 1,904.2

SEGMENTS (Tables)

SEGMENTS (Tables)	9 Months Ended
SEGMENTS (Tables)	Sep. 30, 2019
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 Segments ( Thousands of dollars ) NGL and condensate sales $ 244,932 $ 1,746,630 $ — $ 1,991,562 Residue natural gas sales 185,303 — 231 185,534 Gathering, processing and exchange services revenue 42,795 105,179 — 147,974 Transportation and storage revenue — 46,407 108,384 154,791 Other 3,182 2,291 12,933 18,406 Total revenues (c) 476,212 1,900,507 121,548 2,498,267 Cost of sales and fuel (exclusive of depreciation and operating costs) (210,739 ) (1,438,206 ) (381 ) (1,649,326 ) Operating costs (91,227 ) (114,903 ) (40,170 ) (246,300 ) Equity in net earnings (loss) from investments (1,837 ) 15,890 23,523 37,576 Noncash compensation expense and other 2,883 4,174 (701 ) 6,356 Segment adjusted EBITDA $ 175,292 $ 367,462 $ 103,819 $ 646,573 Depreciation and amortization $ (55,781 ) $ (50,419 ) $ (14,330 ) $ (120,530 ) Capital expenditures $ 245,745 $ 738,038 $ 27,767 $ 1,011,550 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $379.7 million , of which $315.7 million related to revenues within the segment, and cost of sales and fuel of $129.5 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $72.3 million and cost of sales and fuel of $5.1 million . (c) - Intersegment revenues for the Natural Gas Gathering and Processing segment totaled $244.2 million . Intersegment revenues for the Natural Gas Liquids and Natural Gas Pipelines segments were not material. Three Months Ended Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated NGL and condensate sales $ 1,991,562 $ (230,080 ) $ 1,761,482 Residue natural gas sales 185,534 (567 ) 184,967 Gathering, processing and exchange services revenue 147,974 — 147,974 Transportation and storage revenue 154,791 (2,594 ) 152,197 Other 18,406 (1,798 ) 16,608 Total revenues (a) $ 2,498,267 $ (235,039 ) $ 2,263,228 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (1,649,326 ) $ 234,798 $ (1,414,528 ) Operating costs $ (246,300 ) $ 1,165 $ (245,135 ) Depreciation and amortization $ (120,530 ) $ (900 ) $ (121,430 ) Equity in net earnings from investments $ 37,576 $ — $ 37,576 Capital expenditures $ 1,011,550 $ 7,624 $ 1,019,174 (a) - Noncustomer revenue for the three months ended September 30, 2019 , totaled $89.0 million related primarily to gains from commodity derivative contracts. Three Months Ended Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Total Segments ( Thousands of dollars ) NGL and condensate sales $ 501,163 $ 2,861,896 $ — $ 3,363,059 Residue natural gas sales 245,474 — 763 246,237 Gathering, processing and exchange services revenue 41,101 116,833 — 157,934 Transportation and storage revenue — 45,251 98,031 143,282 Other 3,517 2,308 6,400 12,225 Total revenues (c) 791,255 3,026,288 105,194 3,922,737 Cost of sales and fuel (exclusive of depreciation and operating costs) (542,463 ) (2,544,854 ) (2,384 ) (3,089,701 ) Operating costs (90,970 ) (101,126 ) (36,543 ) (228,639 ) Equity in net earnings from investments 74 16,450 22,789 39,313 Noncash compensation expense and other 1,703 2,268 1,050 5,021 Segment adjusted EBITDA $ 159,599 $ 399,026 $ 90,106 $ 648,731 Depreciation and amortization $ (49,223 ) $ (43,688 ) $ (13,625 ) $ (106,536 ) Capital expenditures $ 213,034 $ 444,780 $ 31,522 $ 689,336 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $316.0 million , of which $276.4 million related to revenues within the segment, and cost of sales and fuel of $132.7 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $65.9 million and cost of sales and fuel of $5.5 million . (c) - Intersegment revenues for the Natural Gas Gathering and Processing segment totaled $519.7 million . Intersegment revenues for the Natural Gas Liquids and Natural Gas Pipelines segments were not material. Three Months Ended Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated NGL and condensate sales $ 3,363,059 $ (526,398 ) $ 2,836,661 Residue natural gas sales 246,237 — 246,237 Gathering, processing and exchange services revenue 157,934 — 157,934 Transportation and storage revenue 143,282 (2,370 ) 140,912 Other 12,225 (79 ) 12,146 Total revenues (a) $ 3,922,737 $ (528,847 ) $ 3,393,890 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (3,089,701 ) $ 528,936 $ (2,560,765 ) Operating costs $ (228,639 ) $ (1,732 ) $ (230,371 ) Depreciation and amortization $ (106,536 ) $ (847 ) $ (107,383 ) Equity in net earnings from investments $ 39,313 $ — $ 39,313 Capital expenditures $ 689,336 $ 4,967 $ 694,303 (a) - Noncustomer revenue for the three months ended September 30, 2018 , totaled $(17.7) million related primarily to losses from derivatives on commodity contracts. Nine Months Ended Natural Gas Natural Gas Natural Gas Total Segments ( Thousands of dollars ) NGL and condensate sales $ 890,021 $ 5,826,297 $ — $ 6,716,318 Residue natural gas sales 725,672 — 1,242 726,914 Gathering, processing and exchange services revenue 126,073 309,571 — 435,644 Transportation and storage revenue — 141,384 317,555 458,939 Other 11,287 7,313 36,682 55,282 Total revenues (c) 1,753,053 6,284,565 355,479 8,393,097 Cost of sales and fuel (exclusive of depreciation and operating costs) (971,397 ) (4,914,452 ) (3,785 ) (5,889,634 ) Operating costs (271,236 ) (340,274 ) (113,043 ) (724,553 ) Equity in net earnings (loss) from investments (4,660 ) 49,406 70,429 115,175 Noncash compensation expense and other 8,399 12,618 1,931 22,948 Segment adjusted EBITDA $ 514,159 $ 1,091,863 $ 311,011 $ 1,917,033 Depreciation and amortization $ (162,014 ) $ (143,166 ) $ (42,653 ) $ (347,833 ) Total assets $ 6,546,417 $ 11,662,489 $ 2,083,773 $ 20,292,679 Capital expenditures $ 674,115 $ 1,969,138 $ 77,861 $ 2,721,114 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $1.0 billion , of which $853.0 million related to revenues within the segment, and cost of sales and fuel of $364.9 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $214.7 million and cost of sales and fuel of $14.4 million . (c) - Intersegment revenues for the Natural Gas Gathering and Processing segment totaled $897.9 million . Intersegment revenues for the Natural Gas Liquids and Natural Gas Pipelines segments were not material. Nine Months Ended Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated NGL and condensate sales $ 6,716,318 $ (878,958 ) $ 5,837,360 Residue natural gas sales 726,914 (567 ) 726,347 Gathering, processing and exchange services revenue 435,644 — 435,644 Transportation and storage revenue 458,939 (7,578 ) 451,361 Other 55,282 (5,233 ) 50,049 Total revenues (a) $ 8,393,097 $ (892,336 ) $ 7,500,761 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (5,889,634 ) $ 892,935 $ (4,996,699 ) Operating costs $ (724,553 ) $ 964 $ (723,589 ) Depreciation and amortization $ (347,833 ) $ (2,719 ) $ (350,552 ) Equity in net earnings from investments $ 115,175 $ — $ 115,175 Total assets $ 20,292,679 $ 1,043,228 $ 21,335,907 Capital expenditures $ 2,721,114 $ 18,224 $ 2,739,338 (a) - Noncustomer revenue for the nine months ended September 30, 2019 , totaled $129.9 million related primarily to gains from commodity derivative contracts. Nine Months Ended Natural Gas Gathering and Processing Natural Gas Liquids (a) Natural Gas Pipelines (b) Total Segments ( Thousands of dollars ) NGL and condensate sales $ 1,362,159 $ 7,884,183 $ — $ 9,246,342 Residue natural gas sales 709,089 — 5,861 714,950 Gathering, processing and exchange services revenue 122,331 296,561 — 418,892 Transportation and storage revenue — 143,741 289,646 433,387 Other 6,596 8,202 19,390 34,188 Total revenues (c) 2,200,175 8,332,687 314,897 10,847,759 Cost of sales and fuel (exclusive of depreciation and operating costs) (1,478,044 ) (7,009,438 ) (10,475 ) (8,497,957 ) Operating costs (272,931 ) (289,328 ) (104,692 ) (666,951 ) Equity in net earnings from investments 948 49,456 65,666 116,070 Noncash compensation expense and other 6,868 9,789 3,701 20,358 Segment adjusted EBITDA $ 457,016 $ 1,093,166 $ 269,097 $ 1,819,279 Depreciation and amortization $ (145,120 ) $ (128,993 ) $ (41,320 ) $ (315,433 ) Total assets $ 5,811,140 $ 9,632,212 $ 2,109,897 $ 17,553,249 Capital expenditures $ 433,605 $ 786,635 $ 71,897 $ 1,292,137 (a) - Our Natural Gas Liquids segment has regulated and nonregulated operations. Our Natural Gas Liquids segment’s regulated operations had revenues of $910.3 million , of which $784.8 million related to revenues within the segment, and cost of sales and fuel of $379.5 million . (b) - Our Natural Gas Pipelines segment has regulated and nonregulated operations. Our Natural Gas Pipelines segment’s regulated operations had revenues of $198.4 million and cost of sales and fuel of $20.4 million . (c) - Intersegment revenues for the Natural Gas Gathering and Processing segment totaled $1.4 billion . Intersegment revenues for the Natural Gas Liquids and Natural Gas Pipelines segments were not material. Nine Months Ended Total Segments Other and Eliminations Total ( Thousands of dollars ) Reconciliations of total segments to consolidated NGL and condensate sales $ 9,246,342 $ (1,383,864 ) $ 7,862,478 Residue natural gas sales 714,950 (778 ) 714,172 Gathering, processing and exchange services revenue 418,892 (21 ) 418,871 Transportation and storage revenue 433,387 (6,959 ) 426,428 Other 34,188 359 34,547 Total revenues (a) $ 10,847,759 $ (1,391,263 ) $ 9,456,496 Cost of sales and fuel (exclusive of depreciation and operating costs) $ (8,497,957 ) $ 1,393,348 $ (7,104,609 ) Operating costs $ (666,951 ) $ (3,777 ) $ (670,728 ) Depreciation and amortization $ (315,433 ) $ (2,475 ) $ (317,908 ) Equity in net earnings from investments $ 116,070 $ — $ 116,070 Total assets $ 17,553,249 $ 358,065 $ 17,911,314 Capital expenditures $ 1,292,137 $ 17,518 $ 1,309,655 (a) - Noncustomer revenue for the nine months ended September 30, 2018 , totaled $(32.1) million related primarily to losses from derivatives on commodity contracts. Three Months Ended Nine Months Ended September 30, September 30, 2019 2018 2019 2018 ( Thousands of dollars ) Reconciliation of net income to total segment adjusted EBITDA Net income $ 309,155 $ 313,916 $ 958,326 $ 862,144 Add: Interest expense, net of capitalized interest 129,577 121,910 362,490 351,131 Depreciation and amortization 121,430 107,383 350,552 317,908 Income taxes 97,365 102,983 274,234 266,285 Noncash compensation expense 9,757 5,829 20,412 27,195 Other corporate costs and noncash items (a) (20,711 ) (3,290 ) (48,981 ) (5,384 ) Total segment adjusted EBITDA $ 646,573 $ 648,731 $ 1,917,033 $ 1,819,279 (a) - Includes equity AFUDC related to our capital-growth projects.

SUPPLEMENTAL CONDENSED CONSOL_2

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION (Tables)	9 Months Ended
	Sep. 30, 2019
Condensed Financial Information Disclosure [Abstract]
Condensed Consolidating Statements of Income & Comprehensive Income	Condensed Consolidating Statements of Income and Comprehensive Income Three Months Ended September 30, 2019 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 1,947.8 $ — $ 1,947.8 Services — — — 316.0 (0.6 ) 315.4 Total revenues — — — 2,263.8 (0.6 ) 2,263.2 Cost of sales and fuel (exclusive of items shown separately below) — — — 1,414.5 — 1,414.5 Operating expenses (0.7 ) — — 367.8 (0.6 ) 366.5 (Gain) loss on sale of assets — — 0.1 (0.1 ) — — Operating income 0.7 — (0.1 ) 481.6 — 482.2 Equity in net earnings from investments 470.2 476.1 476.2 29.1 (1,414.0 ) 37.6 Other income (expense), net 11.1 75.4 78.1 8.0 (156.2 ) 16.4 Interest expense, net (78.4 ) (78.1 ) (78.1 ) (51.2 ) 156.2 (129.6 ) Income before income taxes 403.6 473.4 476.1 467.5 (1,414.0 ) 406.6 Income taxes (94.4 ) — — (3.0 ) — (97.4 ) Net income 309.2 473.4 476.1 464.5 (1,414.0 ) 309.2 Less: Preferred stock dividends 0.3 — — — — 0.3 Net income available to common shareholders $ 308.9 $ 473.4 $ 476.1 $ 464.5 $ (1,414.0 ) $ 308.9 Net income $ 309.2 $ 473.4 $ 476.1 $ 464.5 $ (1,414.0 ) $ 309.2 Other comprehensive income (loss), net of tax (94.4 ) 12.4 7.9 5.0 (15.6 ) (84.7 ) Comprehensive income $ 214.8 $ 485.8 $ 484.0 $ 469.5 $ (1,429.6 ) $ 224.5 Three Months Ended September 30, 2018 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 3,083.6 $ — $ 3,083.6 Services — — — 310.8 (0.5 ) 310.3 Total revenues — — — 3,394.4 (0.5 ) 3,393.9 Cost of sales and fuel (exclusive of items shown separately below) — — — 2,560.8 — 2,560.8 Operating expenses 2.0 — — 336.3 (0.5 ) 337.8 Gain on sale of assets — — — (0.2 ) — (0.2 ) Operating income (2.0 ) — — 497.5 — 495.5 Equity in net earnings from investments 457.3 457.1 457.1 30.1 (1,362.3 ) 39.3 Other income (expense), net 9.3 80.3 80.3 (5.3 ) (160.6 ) 4.0 Interest expense, net (49.1 ) (80.3 ) (80.3 ) (72.8 ) 160.6 (121.9 ) Income before income taxes 415.5 457.1 457.1 449.5 (1,362.3 ) 416.9 Income taxes (102.3 ) — — (0.7 ) — (103.0 ) Net income 313.2 457.1 457.1 448.8 (1,362.3 ) 313.9 Less: Net income attributable to noncontrolling interests — — — 0.7 — 0.7 Net income attributable to ONEOK 313.2 457.1 457.1 448.1 (1,362.3 ) 313.2 Less: Preferred stock dividends 0.2 — — — — 0.2 Net income available to common shareholders $ 313.0 $ 457.1 $ 457.1 $ 448.1 $ (1,362.3 ) $ 313.0 Net income $ 313.2 $ 457.1 $ 457.1 $ 448.8 $ (1,362.3 ) $ 313.9 Other comprehensive income (loss), net of tax 23.4 (3.7 ) (8.1 ) (7.3 ) 16.2 20.5 Comprehensive income 336.6 453.4 449.0 441.5 (1,346.1 ) 334.4 Less: Comprehensive income attributable to noncontrolling interest — — — 0.7 — 0.7 Comprehensive income attributable to ONEOK $ 336.6 $ 453.4 $ 449.0 $ 440.8 $ (1,346.1 ) $ 333.7 Nine Months Ended September 30, 2019 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 6,567.6 $ — $ 6,567.6 Services — — — 934.8 (1.6 ) 933.2 Total revenues — — — 7,502.4 (1.6 ) 7,500.8 Cost of sales and fuel (exclusive of items shown separately below) — — — 4,996.7 — 4,996.7 Operating expenses (0.7 ) — — 1,076.5 (1.6 ) 1,074.2 Loss on sale of assets — — 2.7 0.2 — 2.9 Operating income 0.7 — (2.7 ) 1,429.0 — 1,427.0 Equity in net earnings from investments 1,392.9 1,405.6 1,408.3 87.1 (4,178.7 ) 115.2 Other income (expense), net 26.3 232.8 235.5 29.3 (471.0 ) 52.9 Interest expense, net (198.1 ) (235.5 ) (235.5 ) (164.4 ) 471.0 (362.5 ) Income before income taxes 1,221.8 1,402.9 1,405.6 1,381.0 (4,178.7 ) 1,232.6 Income taxes (263.5 ) — — (10.8 ) — (274.3 ) Net income 958.3 1,402.9 1,405.6 1,370.2 (4,178.7 ) 958.3 Less: Preferred stock dividends 0.8 — — — — 0.8 Net income available to common shareholders $ 957.5 $ 1,402.9 $ 1,405.6 $ 1,370.2 $ (4,178.7 ) $ 957.5 Net income $ 958.3 $ 1,402.9 $ 1,405.6 $ 1,370.2 $ (4,178.7 ) $ 958.3 Other comprehensive income (loss), net of tax (226.0 ) (9.0 ) (22.5 ) (20.6 ) 45.3 (232.8 ) Comprehensive income $ 732.3 $ 1,393.9 $ 1,383.1 $ 1,349.6 $ (4,133.4 ) $ 725.5 Nine Months Ended September 30, 2018 ( Unaudited ) Parent Issuer & Guarantor Subsidiary Issuer & Guarantor Guarantor Subsidiary Combined Non-Guarantor Subsidiaries Consolidating Entries Total ( Millions of dollars ) Revenues Commodity sales $ — $ — $ — $ 8,578.9 $ — $ 8,578.9 Services — — — 879.1 (1.5 ) 877.6 Total revenues — — — 9,458.0 (1.5 ) 9,456.5 Cost of sales and fuel (exclusive of items shown separately below) — — — 7,104.6 — 7,104.6 Operating expenses 3.3 — — 986.8 (1.5 ) 988.6 Gain on sale of assets — — — (0.3 ) — (0.3 ) Operating income (3.3 ) — — 1,366.9 — 1,363.6 Equity in net earnings from investments 1,226.6 1,231.2 1,231.2 86.2 (3,659.1 ) 116.1 Other income (expense), net 23.1 234.9 234.9 (23.3 ) (469.8 ) (0.2 ) Interest expense, net (129.2 ) (234.9 ) (234.9 ) (221.9 ) 469.8 (351.1 ) Income before income taxes 1,117.2 1,231.2 1,231.2 1,207.9 (3,659.1 ) 1,128.4 Income taxes (258.4 ) — — (7.9 ) — (266.3 ) Net income 858.8 1,231.2 1,231.2 1,200.0 (3,659.1 ) 862.1 Less: Net income attributable to noncontrolling interests — — — 3.3 — 3.3 Net income attributable to ONEOK 858.8 1,231.2 1,231.2 1,196.7 (3,659.1 ) 858.8 Less: Preferred stock dividends 0.8 — — — — 0.8 Net income available to common shareholders $ 858.0 $ 1,231.2 $ 1,231.2 $ 1,196.7 $ (3,659.1 ) $ 858.0 Net income $ 858.8 $ 1,231.2 $ 1,231.2 $ 1,200.0 $ (3,659.1 ) $ 862.1 Other comprehensive income (loss), net of tax 65.6 4.0 (6.9 ) (8.0 ) 13.8 68.5 Comprehensive income 924.4 1,235.2 1,224.3 1,192.0 (3,645.3 ) 930.6 Less: Comprehensive income attributable to noncontrolling interest — — — 3.3 — 3.3 Comprehensive income attributable to ONEOK $ 924.4 $ 1,235.2 $ 1,224.3 $ 1,188.7 $ (3,645.3 ) $ 927.3
Condensed Consolidating Balance Sheets	Condensed Consolidating Balance Sheets September 30, 2019 ( 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 $ 673.3 $ — $ — $ — $ — $ 673.3 Accounts receivable, net — — — 718.7 — 718.7 Materials and supplies — — — 192.9 — 192.9 Natural gas and NGLs in storage — — — 283.5 — 283.5 Other current assets 12.3 — — 86.8 — 99.1 Total current assets 685.6 — — 1,281.9 — 1,967.5 Property, plant and equipment Property, plant and equipment 160.0 — — 20,788.3 — 20,948.3 Accumulated depreciation and amortization 97.6 — — 3,487.8 — 3,585.4 Net property, plant and equipment 62.4 — — 17,300.5 — 17,362.9 Investments and other assets Investments 6,554.5 3,932.2 10,986.9 770.6 (21,373.7 ) 870.5 Intercompany receivable 8,099.1 6,897.7 — — (14,996.8 ) — Other assets 134.8 — — 1,001.1 (0.9 ) 1,135.0 Total investments and other assets 14,788.4 10,829.9 10,986.9 1,771.7 (36,371.4 ) 2,005.5 Total assets $ 15,536.4 $ 10,829.9 $ 10,986.9 $ 20,354.1 $ (36,371.4 ) $ 21,335.9 Liabilities and equity Current liabilities Current maturities of long-term debt $ — $ — $ — $ 7.7 $ — $ 7.7 Accounts payable 9.5 — — 1,120.3 — 1,129.8 Other current liabilities 96.4 63.5 — 269.7 — 429.6 Total current liabilities 105.9 63.5 — 1,397.7 — 1,567.1 Intercompany payable — — 7,054.7 7,942.1 (14,996.8 ) — Long-term debt, excluding current maturities 8,419.6 4,044.3 — 15.6 — 12,479.5 Deferred credits and other liabilities Deferred income taxes 297.9 — — 121.7 (0.9 ) 418.7 Other deferred credits 494.1 — — 157.6 — 651.7 Total deferred credits and other liabilities 792.0 — — 279.3 (0.9 ) 1,070.4 Commitments and contingencies Equity 6,218.9 6,722.1 3,932.2 10,719.4 (21,373.7 ) 6,218.9 Total liabilities and equity $ 15,536.4 $ 10,829.9 $ 10,986.9 $ 20,354.1 $ (36,371.4 ) $ 21,335.9 December 31, 2018 ( 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 $ 12.0 $ — $ — $ — $ — $ 12.0 Accounts receivable, net — — — 819.0 — 819.0 Materials and supplies — — — 141.2 — 141.2 Natural gas and NGLs in storage — — — 296.7 — 296.7 Other current assets 29.1 — — 100.6 — 129.7 Total current assets 41.1 — — 1,357.5 — 1,398.6 Property, plant and equipment Property, plant and equipment 145.5 — — 17,885.5 — 18,031.0 Accumulated depreciation and amortization 92.0 — — 3,172.3 — 3,264.3 Net property, plant and equipment 53.5 — — 14,713.2 — 14,766.7 Investments and other assets Investments 6,153.5 3,548.1 9,721.6 791.1 (19,245.1 ) 969.2 Intercompany receivable 5,308.6 7,701.5 1,528.0 — (14,538.1 ) — Other assets 115.9 — — 982.3 (1.0 ) 1,097.2 Total investments and other assets 11,578.0 11,249.6 11,249.6 1,773.4 (33,784.2 ) 2,066.4 Total assets $ 11,672.6 $ 11,249.6 $ 11,249.6 $ 17,844.1 $ (33,784.2 ) $ 18,231.7 Liabilities and equity Current liabilities Current maturities of long-term debt $ — $ 500.0 $ — $ 7.7 $ — $ 507.7 Accounts payable 31.3 — — 1,085.0 — 1,116.3 Other current liabilities 123.2 81.0 — 280.2 — 484.4 Total current liabilities 154.5 581.0 — 1,372.9 — 2,108.4 Intercompany payable — — 7,701.5 6,836.6 (14,538.1 ) — Long-term debt, excluding current maturities 4,510.7 4,341.4 — 21.2 — 8,873.3 Deferred credits and other liabilities Deferred income taxes 112.3 — — 108.4 (1.0 ) 219.7 Other deferred credits 315.6 — — 135.2 — 450.8 Total deferred credits and other liabilities 427.9 — — 243.6 (1.0 ) 670.5 Commitments and contingencies Equity 6,579.5 6,327.2 3,548.1 9,369.8 (19,245.1 ) 6,579.5 Total liabilities and equity $ 11,672.6 $ 11,249.6 $ 11,249.6 $ 17,844.1 $ (33,784.2 ) $ 18,231.7
Condensed Consolidating Statements of Cash Flows	Condensed Consolidating Statements of Cash Flows Nine Months Ended September 30, 2019 ( 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 $ 761.9 $ 897.3 $ 50.6 $ 1,615.0 $ (1,998.0 ) $ 1,326.8 Investing activities Capital expenditures (17.8 ) — — (2,721.5 ) — (2,739.3 ) Contributions to unconsolidated affiliates — — — (3.3 ) — (3.3 ) Other investing activities — — 72.5 22.2 — 94.7 Cash used in investing activities (17.8 ) — 72.5 (2,702.6 ) — (2,647.9 ) Financing activities Dividends paid (1,079.4 ) (999.0 ) (999.0 ) — 1,998.0 (1,079.4 ) Intercompany borrowings (advances), net (2,874.4 ) 904.1 875.9 1,094.4 — — Issuance of long-term debt, net of discounts 4,185.4 — — — — 4,185.4 Repayment of long-term debt (250.0 ) (799.7 ) — (5.7 ) — (1,055.4 ) Issuance of common stock 19.3 — — — — 19.3 Other (83.7 ) (2.7 ) — (1.1 ) — (87.5 ) Cash provided by financing activities (82.8 ) (897.3 ) (123.1 ) 1,087.6 1,998.0 1,982.4 Change in cash and cash equivalents 661.3 — — — — 661.3 Cash and cash equivalents at beginning of period 12.0 — — — — 12.0 Cash and cash equivalents at end of period $ 673.3 $ — $ — $ — $ — $ 673.3 Nine Months Ended September 30, 2018 ( 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 $ 964.4 $ 993.8 $ 48.9 $ 1,507.4 $ (1,998.0 ) $ 1,516.5 Investing activities Capital expenditures (15.0 ) — — (1,294.7 ) — (1,309.7 ) Contributions to unconsolidated affiliates — — (0.5 ) (0.3 ) — (0.8 ) Other investing activities — — 10.8 9.9 — 20.7 Cash used in investing activities (15.0 ) — 10.3 (1,285.1 ) — (1,289.8 ) Financing activities Dividends paid (983.1 ) (999.0 ) (999.0 ) — 1,998.0 (983.1 ) Distributions to noncontrolling interests — — — (3.5 ) — (3.5 ) Intercompany borrowings (advances), net (1,640.5 ) 930.2 939.8 (229.5 ) — — Borrowing (repayment) of short-term borrowings, net (494.7 ) — — — — (494.7 ) Issuance of long-term debt, net of discounts 1,245.8 — — — — 1,245.8 Repayment of long-term debt — (925.0 ) — (5.7 ) — (930.7 ) Issuance of common stock 1,195.1 — — — — 1,195.1 Acquisition of noncontrolling interests (195.0 ) — — — — (195.0 ) Other, net (29.7 ) — — 16.4 — (13.3 ) Cash used in financing activities (902.1 ) (993.8 ) (59.2 ) (222.3 ) 1,998.0 (179.4 ) Change in cash and cash equivalents 47.3 — — — — 47.3 Cash and cash equivalents at beginning of period 37.2 — — — — 37.2 Cash and cash equivalents at end of period $ 84.5 $ — $ — $ — $ — $ 84.5

FAIR VALUE MEASUREMENTS - Part

FAIR VALUE MEASUREMENTS - Part 1 (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
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	1,900	800
Long-term debt, Fair Value	13,700,000	9,600,000
Long-term debt	12,500,000	9,400,000
Fair Value, Recurring [Member]
Derivative assets
Financial contracts	39,903	47,238
Physical contracts	579	1,142
Interest-rate contracts		19,005
Total derivative assets	40,482	67,385
Derivative assets netting	(40,413)	(32,739)
Derivative liabilities
Financial contracts	0	0
Interest-rate contracts	(276,865)	(99,260)
Total derivative liabilities	(276,865)	(99,260)
Derivative liabilities netting	40,413	32,739
Fair Value, Recurring [Member] \| Financial Contracts [Member]
Derivative assets
Derivative assets netting	(40,413)	(32,739)
Derivative liabilities
Derivative liabilities netting	40,413	32,739
Fair Value, Recurring [Member] \| Interest Rate Contract [Member]
Derivative assets
Derivative assets netting		0
Derivative liabilities
Derivative liabilities netting	0	0
Fair Value, Recurring [Member] \| Physical Contracts [Member]
Derivative assets
Derivative assets netting	0	0
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 1 [Member]
Derivative assets
Financial contracts	12,267	10,812
Physical contracts	0	0
Interest-rate contracts		0
Total derivative assets	12,267	10,812
Derivative liabilities
Financial contracts	0	(2,916)
Interest-rate contracts	0	0
Total derivative liabilities	0	(2,916)
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 2 [Member]
Derivative assets
Financial contracts	0	0
Physical contracts	0	0
Interest-rate contracts		19,005
Total derivative assets	0	19,005
Derivative liabilities
Financial contracts	0	0
Interest-rate contracts	(276,865)	(99,260)
Total derivative liabilities	(276,865)	(99,260)
Fair Value, Recurring [Member] \| Fair Value, Inputs, Level 3 [Member]
Derivative assets
Financial contracts	68,049	69,165
Physical contracts	579	1,142
Interest-rate contracts		0
Total derivative assets	68,628	70,307
Derivative liabilities
Financial contracts	(40,413)	(29,823)
Interest-rate contracts	0	0
Total derivative liabilities	(40,413)	(29,823)
Fair Value, Recurring [Member] \| Estimate of Fair Value Measurement [Member]
Derivative assets
Financial contracts	80,316	79,977
Physical contracts	579	1,142
Interest-rate contracts		19,005
Total derivative assets	80,895	100,124
Derivative liabilities
Financial contracts	(40,413)	(32,739)
Interest-rate contracts	(276,865)	(99,260)
Total derivative liabilities	$ (317,278)	$ (131,999)

FAIR VALUE MEASUREMENTS - Par_2

FAIR VALUE MEASUREMENTS - Part 2 (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Fair Value, Assets And Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation [Abstract]
Net assets (liabilities) at beginning of period	$ 19,274	$ (23,501)	$ 40,484	$ (32,838)
Total realized/unrealized gains (losses):
Included in earnings	0	(22)	0	(122)
Included in other comprehensive income (loss)	8,941	(7,554)	(12,269)	1,883
Net assets (liabilities) at end of period	28,215	(31,077)	28,215	(31,077)
Transfers between levels	$ 0	$ 0	$ 0	$ 0

RISK MANAGEMENT AND HEDGING A_3

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES Part 1 (Details) - USD ($)	9 Months Ended
	Sep. 30, 2019	Dec. 31, 2018
Derivative, Fair Value [Line Items]
Derivative, Net Liability Position, Aggregate Fair Value	$ 0
Notional Amount Of Cash Flow Hedge Instruments Settled	1,800,000,000
Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	80,895,000	$ 100,124,000
(Liabilities)	(317,278,000)	(131,999,000)
Natural Gas Pipelines [Member]
Derivative, Fair Value [Line Items]
Derivative, Fair Value, Net	0	0
Other Current Assets [Member] \| Commodity contracts (a) \| Financial contracts \| Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	72,995,000	78,891,000
(Liabilities)	(36,186,000)	(31,793,000)
Other Current Assets [Member] \| Commodity contracts (a) \| Physical contracts \| Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	579,000	1,142,000
(Liabilities)	0	0
Other Current Assets [Member] \| Interest-rate contracts \| Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	0	19,005,000
Other Current Liabilities \| Interest-rate contracts \| Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
(Liabilities)	(14,672,000)	(15,012,000)
Other Assets [Member] \| Commodity contracts (a) \| Financial contracts \| Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	7,321,000	1,086,000
(Liabilities)	(4,227,000)	(946,000)
Other Deferred Credits \| Interest-rate contracts \| Derivatives designated as hedging instruments
Derivative, Fair Value [Line Items]
Assets	0	0
(Liabilities)	(262,193,000)	(84,248,000)
Forecasted Debt Issuances [Member] \| Cash Flow Hedging [Member] \| Forward Contracts [Member]
Derivative, Fair Value [Line Items]
Derivative, Notional Amount, New Contracts	625,000,000
Interest-rate contracts \| Forecasted Debt Issuances [Member] \| Cash Flow Hedging [Member] \| Forward Contracts [Member]
Derivative, Fair Value [Line Items]
Derivative, Notional Amount	1,800,000,000	3,000,000,000
Interest-rate contracts \| LIBOR Based Interest Payments [Member] \| Cash Flow Hedging [Member] \| Forward Contracts [Member]
Derivative, Fair Value [Line Items]
Derivative, Notional Amount	$ 1,300,000,000	$ 1,300,000,000

RISK MANAGEMENT AND HEDGING A_4

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES, Part 2 (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019USD ($)MMcfMMBbls	Dec. 31, 2018USD ($)MMcfMMBbls
Derivative [Line Items]
Notional Amount Of Cash Flow Hedge Instruments Settled	$ 1,800,000
Designated as Hedging Instrument [Member] \| Futures and swaps \| - Natural gas (Bcf) \| Fixed price \| Purchased/ Payor
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount \| MMcf	0	0
Designated as Hedging Instrument [Member] \| Futures and swaps \| - Natural gas (Bcf) \| Fixed price \| Sold/ Receiver
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount \| MMcf	(39,600)	(29,900)
Designated as Hedging Instrument [Member] \| Futures and swaps \| - Natural gas (Bcf) \| Basis \| Purchased/ Payor
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount \| MMcf	0	0
Designated as Hedging Instrument [Member] \| Futures and swaps \| - Natural gas (Bcf) \| Basis \| Sold/ Receiver
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount \| MMcf	(39,600)	(29,900)
Designated as Hedging Instrument [Member] \| Futures, forwards, swaps and options \| - Crude oil and NGLs (MMBbl) \| Fixed price \| Purchased/ Payor
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount \| MMBbls	9.2	6.5
Designated as Hedging Instrument [Member] \| Futures, forwards, swaps and options \| - Crude oil and NGLs (MMBbl) \| Fixed price \| Sold/ Receiver
Derivative [Line Items]
Derivative, Nonmonetary Notional Amount \| MMBbls	(20.1)	(13.8)
Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Purchased/ Payor
Derivative [Line Items]
Derivative, Notional Amount	$ 3,100,000	$ 4,300,000
Designated as Hedging Instrument [Member] \| Interest Rate Contract [Member] \| Sold/ Receiver
Derivative [Line Items]
Derivative, Notional Amount	0	0
LIBOR Based Interest Payments [Member] \| Cash Flow Hedging [Member] \| Forward Contracts [Member] \| Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount	1,300,000	1,300,000
Forecasted Debt Issuances [Member] \| Cash Flow Hedging [Member] \| Forward Contracts [Member]
Derivative [Line Items]
Derivative, Notional Amount, New Contracts	625,000
Forecasted Debt Issuances [Member] \| Cash Flow Hedging [Member] \| Forward Contracts [Member] \| Interest Rate Contract [Member]
Derivative [Line Items]
Derivative, Notional Amount	1,800,000	$ 3,000,000
Notes Payable from Public Offering Due 2029 and 2048 [Member]
Derivative [Line Items]
Senior Notes, Noncurrent	1,250,000
Notes Payable from Public Offering Due 2024, 2029 and 2049 [Member]
Derivative [Line Items]
Senior Notes, Noncurrent	$ 2,000,000

RISK MANAGEMENT AND HEDGING A_5

RISK MANAGEMENT AND HEDGING ACTIVITIES USING DERIVATIVES Part 3 (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized change in fair value of cash flow hedges in other comprehensive income (loss)	$ (95,872)	$ (4,580)	$ (259,474)	$ 13,933
Change in fair value of cash flow hedges reclassified from accumulated other comprehensive loss into net income	11,625	(25,013)	38,402	(56,359)
Commodity contracts \| Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized change in fair value of cash flow hedges in other comprehensive income (loss)	32,169	(30,783)	43,877	(56,246)
Commodity contracts \| Commodity sales revenues/ cost of sales and fuel \| Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of cash flow hedges reclassified from accumulated other comprehensive loss into net income		(20,630)		(42,430)
Interest Rate Contract [Member] \| Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Unrealized change in fair value of cash flow hedges in other comprehensive income (loss)	(128,041)	26,203	(303,351)	70,179
Interest Rate Contract [Member] \| Interest expense \| Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of cash flow hedges reclassified from accumulated other comprehensive loss into net income		(4,383)		(13,929)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] \| Commodity contracts \| Commodity sales revenues/ cost of sales and fuel
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of cash flow hedges reclassified from accumulated other comprehensive loss into net income	18,528	(20,630)	52,624	(42,430)
Accumulated Net Gain (Loss) from Cash Flow Hedges Attributable to Parent [Member] \| Interest Rate Contract [Member] \| Interest expense
Derivative Instruments, Gain (Loss) [Line Items]
Change in fair value of cash flow hedges reclassified from accumulated other comprehensive loss into net income	$ (6,903)	$ (4,383)	$ (14,222)	$ (13,929)

DEBT DEBT (Details)

DEBT DEBT (Details)	9 Months Ended
DEBT DEBT (Details)	Sep. 30, 2019USD ($)Rate	Dec. 31, 2018USD ($)
Debt Instrument [Line Items]
Total Debt	$ 12,595,617,000	$ 9,451,354,000
Unamortized Portion of Terminated Swaps	15,461,000	16,750,000
Unamortized debt issuance costs and discounts	(123,976,000)	(87,120,000)
Current maturities of long-term debt	(7,650,000)	(507,650,000)
Long-term debt	12,479,452,000	8,873,334,000
$2.5 Billion Credit Agreement [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity	2,500,000,000
Line of Credit Facility, Amount Outstanding	$ 0
Indebtedness To Adjusted Ebitda Current	4.2
Indebtedness To Adjusted EBITDA Maximum	5
Indebtedness To Adjusted EBITDA From Acquisitions Maximum	5.5
Aggregate Purchase Price For Acquisitions Threshold Which Adjusts Allowable Ratio Of Indebtedness To Adjusted EBITDA	$ 25,000,000
Debt Instrument, Covenant Description	Among other things, these covenants include maintaining a ratio of indebtedness to adjusted EBITDA (EBITDA, as defined in our $2.5 Billion Credit Agreement, adjusted for all noncash charges and increased for projected EBITDA from certain lender-approved capital expansion projects) of no more than 5.0 to 1 at September 30, 2019. 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. Thereafter, the covenant will decrease to 5.0 to 1. At September 30, 2019, we had no borrowings outstanding, our ratio of indebtedness to adjusted EBITDA was 3.8 to 1, and we were in compliance with all covenants under our $2.5 Billion Credit Agreement.
Notes Payable from Public Offering Due 2024, 2029 and 2049 [Member]
Debt Instrument [Line Items]
Senior Notes, Noncurrent	$ 2,000,000,000
Proceeds from Debt, Net of Issuance Costs	1,970,000,000
Notes Payable from Public Offering Due 2029 and 2048 [Member]
Debt Instrument [Line Items]
Senior Notes, Noncurrent	1,250,000,000
Proceeds from Debt, Net of Issuance Costs	1,230,000,000
Guardian Pipeline [Member] \| Notes Payables 1 due 2022 [Member]
Debt Instrument [Line Items]
Total Debt	$ 23,220,000	28,957,000
Weighed Average Interest Rate (in hundredths) \| Rate	7.85%
Subsidiary Issuer [Member] \| Notes Payables due 2019 [Member]
Debt Instrument [Line Items]
Total Debt	$ 0	500,000,000
Repayments of Long-term Debt	$ 500,000,000
Interest Rate (in hundredths) \| Rate	8.625%
Subsidiary Issuer [Member] \| Note Payable from Public Offering Due 2020 [Member]
Debt Instrument [Line Items]
Total Debt	$ 0	300,000,000
Extinguishment of Debt	300,000,000
Gain (Loss) on Extinguishment of Debt	$ (2,700,000)
Interest Rate (in hundredths) \| Rate	3.80%
Redemption Price	$ 308,000,000
Subsidiary Issuer [Member] \| Note Payable 2 from Public Offering Due 2022 [Member]
Debt Instrument [Line Items]
Total Debt	$ 900,000,000	900,000,000
Interest Rate (in hundredths) \| Rate	3.375%
Subsidiary Issuer [Member] \| Note Payable from Public Offering Due 2023 [Member]
Debt Instrument [Line Items]
Total Debt	$ 425,000,000	425,000,000
Interest Rate (in hundredths) \| Rate	5.00%
Subsidiary Issuer [Member] \| Note Payable from Public Offering Due 2025 [Member]
Debt Instrument [Line Items]
Total Debt	$ 500,000,000	500,000,000
Interest Rate (in hundredths) \| Rate	4.90%
Subsidiary Issuer [Member] \| Notes Payables due 2036 [Member]
Debt Instrument [Line Items]
Total Debt	$ 600,000,000	600,000,000
Interest Rate (in hundredths) \| Rate	6.65%
Subsidiary Issuer [Member] \| Notes Payables due 2037 [Member]
Debt Instrument [Line Items]
Total Debt	$ 600,000,000	600,000,000
Interest Rate (in hundredths) \| Rate	6.85%
Subsidiary Issuer [Member] \| Note Payable from Public Offering Due 2041 [Member]
Debt Instrument [Line Items]
Total Debt	$ 650,000,000	650,000,000
Interest Rate (in hundredths) \| Rate	6.125%
Subsidiary Issuer [Member] \| Note Payable from Public Offering Due 2043 [Member]
Debt Instrument [Line Items]
Total Debt	$ 400,000,000	400,000,000
Interest Rate (in hundredths) \| Rate	6.20%
Parent Company
Debt Instrument [Line Items]
Commercial Paper	$ 0	0
Parent Company \| Term Loan Agreement due 2021 [Member]
Debt Instrument [Line Items]
Total Debt	1,250,000,000	550,000,000
Debt Instrument, Face Amount	1,500,000,000
Repayments of Long-term Debt	250,000,000
Parent Company \| Note Payable from Public Offering Due 2022 [Member]
Debt Instrument [Line Items]
Total Debt	$ 547,397,000	547,397,000
Interest Rate (in hundredths) \| Rate	4.25%
Parent Company \| Note Payable Due 2023 [Member]
Debt Instrument [Line Items]
Total Debt	$ 500,000,000	500,000,000
Interest Rate (in hundredths) \| Rate	7.50%
Parent Company \| Note Payable Due 2024 [Member]
Debt Instrument [Line Items]
Total Debt	$ 500,000,000	0
Interest Rate (in hundredths) \| Rate	2.75%
Parent Company \| Note Payable Due 2027 [Member]
Debt Instrument [Line Items]
Total Debt	$ 500,000,000	500,000,000
Interest Rate (in hundredths) \| Rate	4.00%
Parent Company \| Note Payables 1 due 2028 [Member]
Debt Instrument [Line Items]
Total Debt	$ 800,000,000	800,000,000
Interest Rate (in hundredths) \| Rate	4.55%
Parent Company \| Note Payables 2 due 2028 [Member]
Debt Instrument [Line Items]
Total Debt	$ 100,000,000	100,000,000
Interest Rate (in hundredths) \| Rate	6.875%
Parent Company \| Note Payable from Public Offering Due 2029 [Member]
Debt Instrument [Line Items]
Total Debt	$ 700,000,000	0
Interest Rate (in hundredths) \| Rate	4.35%
Parent Company \| Note Payable Due 2029 [Member]
Debt Instrument [Line Items]
Total Debt	$ 750,000,000	0
Interest Rate (in hundredths) \| Rate	3.40%
Parent Company \| Notes Payables due 2035 [Member]
Debt Instrument [Line Items]
Total Debt	$ 400,000,000	400,000,000
Interest Rate (in hundredths) \| Rate	6.00%
Parent Company \| Notes Payables due 2047 [Member]
Debt Instrument [Line Items]
Total Debt	$ 700,000,000	700,000,000
Interest Rate (in hundredths) \| Rate	4.95%
Parent Company \| Note Payables due 2048 [Member]
Debt Instrument [Line Items]
Total Debt	$ 1,000,000,000	450,000,000
Interest Rate (in hundredths) \| Rate	5.20%
Parent Company \| Note Payable Due 2049 [Member]
Debt Instrument [Line Items]
Total Debt	$ 750,000,000	$ 0
Interest Rate (in hundredths) \| Rate	4.45%
Parent Company \| Note Payables, Additional Issuance, due 2048 [Member]
Debt Instrument [Line Items]
Total Debt	$ 550,000,000
London Interbank Offered Rate (LIBOR) [Member] \| Parent Company \| Term Loan Agreement due 2021 [Member]
Debt Instrument [Line Items]
Debt Instrument, Basis Spread on Variable Rate	1.125%

EQUITY (Details)

EQUITY (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								9 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2017	Sep. 30, 2019
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners						20.00%
Business Combination, Consideration Transferred					$ 195,000
Common Stock, Dividends, Per Share, Cash Paid		$ 0.89	$ 0.865	$ 0.86	$ 0.825	$ 0.795	$ 0.77
Dividends, Preferred Stock, Cash		$ 300	$ 300	$ 300
Preferred Stock, Dividends, Declared		$ 275	$ 275	$ 275	$ 275	$ 275	$ 275
Stock Issued During Period, Shares, New Issues							21,900,000
Proceeds from Issuance or Sale of Equity							$ 1,200,000
Aggregate Amount Of Common Shares Available For Issuance And Sale Under Equity Distribution Agreement								$ 1,000,000
Issued Under Equity Agreement [Member]
Common Stock Sold Under Equity Distribution Agreement									0
Series E Preferred Stock [Member]
Preferred Stock, Dividend Rate, Percentage									5.50%
Subsequent Event [Member]
Common Stock, Dividends, Per Share, Declared	$ 0.915
Dividends Payable, Date of Record	Nov. 4, 2019
Dividends Payable, Date to be Paid	Nov. 14, 2019
Preferred Stock, Dividends, Declared	$ 300

ACCUMULATED OTHER COMPREHENSI_3

ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) ACCUMULATED OTHER COMPREHENSIVE INCOME (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Risk management assets/liabilities - January 1			$ (64,660)				$ (64,660)
Retirement and Other Postretirement Benefit Plan Obligations - January 1			(121,785)				(121,785)
Risk-management assets/liabilities of unconsolidated affiliates - January 1			(1,794)				(1,794)
Accumulated other comprehensive loss - January 1			(188,239)				(188,239)
Change in fair value of derivatives, net of tax	$ (73,822)			$ (3,526)			(199,795)	$ 10,729
Other Comprehensive (Income) Loss Before Reclassification, Retirement and Postretirement Benefit Plan Obligations							(63)
Other Comprehensive Income (Loss) Before Reclassification, Risk-Management Assets/Liabilities of Unconsolidated Affiliates							(10,567)
Other comprehensive income (loss) before reclassifications							(210,425)
Other comprehensive Income (Loss) Reclassification Adjustment from AOCI for Risk-Management Assets/Liabilities, Net of Tax	(8,952)			19,261			(29,748)	43,397
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Other Comprehensive Income Attributable to Unconsolidated Affiliates, Net of Tax							26
Other comprehensive Income (Loss), Reclassification Adjustment included in Net Income, Net of Tax	(6,462)			22,437			(22,440)	52,991
Other Comprehensive Income (Loss), Risk-Management Assets/Liabilities, after Reclassification Adjustment, after Tax							(229,543)
Other Comprehensive (Income) Loss, Retirement and Other Postretirement Benefit Plans, after Reclassification Adjustment, after Tax	2,465			3,236			7,271	9,086
Other Comprehensive Income (Loss), Risk-Management Assets/Liabilities of Unconsolidated Affiliates	(4,399)			1,480			(10,593)	5,281
Other Comprehensive Income (Loss), Net of Tax	(84,708)	$ (66,872)	(81,285)	20,451	$ (3,897)	$ 51,939	(232,865)	68,493
Risk management assets/liabilities - September 30	(294,203)						(294,203)
Retirement and Other Postretirement Benefit Plan Obligations - September 30	(114,514)						(114,514)
Risk-management assets/liabilities of unconsolidated affiliates - September 30	(12,387)						(12,387)
Accumulated other comprehensive loss - September 30	(421,104)						(421,104)
Reclassification Adjustment from AOCI on Risk Management Assets/Liabilities, Income Tax	(2,673)			5,752			(8,654)	12,962
Price Risk Cash Flow Hedge Unrealized Gain (Loss) to be Reclassified During Next 12 Months	27,900						27,900
Commodity Cash Flow Hedge Gain (Loss) To Be Reclassified After Next 12 Months Net	2,400						2,400
Interest Rate Cash Flow Hedge Gain (Loss) to be Reclassified During Next 12 Months, Net	(19,700)						(19,700)
Accumulated Net Gain (Loss) from Cash Flow Hedges [Member] \| Sales [Member] \| Commodity contracts
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Net	18,528			(20,630)			52,624	(42,430)
Accumulated Net Gain (Loss) from Cash Flow Hedges [Member] \| Interest Expense [Member] \| Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Net	(6,903)			(4,383)			(14,222)	(13,929)
Accumulated Net Gain (Loss) from Cash Flow Hedges [Member] \| Total before tax [Member]
Derivative instruments, Gain (Loss) Reclassified from Accumulated OCI into Income	11,625			(25,013)			38,402	(56,359)
Accumulated Net Gain (Loss) from Cash Flow Hedges [Member] \| Tax Expense [Member]
Reclassification Adjustment from AOCI on Risk Management Assets/Liabilities, Income Tax	(2,673)			5,752			(8,654)	12,962
Accumulated Net Gain (Loss) from Cash Flow Hedges [Member] \| Net of tax [Member]
Other comprehensive Income (Loss) Reclassification Adjustment from AOCI for Risk-Management Assets/Liabilities, Net of Tax	(8,952)			19,261			(29,748)	43,397
Accumulated Retirement and Other Postretirement Benefit Plans Adjustment [Member]
Other Comprehensive (Income) Loss, Retirement and Other Postretirement Benefit Plans, Reclassification Adjustment from AOCI, After Tax	(2,444)			(3,216)			(7,334)	(9,649)
Retirement and Other Postretirement Benefit Plans, Amortization of Gain (Loss)	(3,232)			(4,592)			(9,696)	(13,776)
Retirement and Other Postretirement Benefit Plans, Amortization of Prior Service Credit	57			415			171	1,245
Reclassification Adjustment from AOCI, before Tax, Retirement and Other Postretirement Benefit Plans, Gain (Loss)	(3,175)			(4,177)			(9,525)	(12,531)
Reclassification Adjustment from AOCI, Tax, Retirement and Other Postretirement Benefit Plans, Gain (Loss)	731			961			2,191	2,882
Accumulated Other Comprehensive Income from Investments in Unconsolidated Affiliates [Member]
Reclassification Adjustment from AOCI, Before Tax, Portion Attributable to Unconsolidated Affiliates	(59)			52			34	71
Reclassification Adjustment from AOCI, Tax, Portion Attributable to Unconsolidated Affiliates	13			(12)			(8)	(16)
Accumulated Other Comprehensive Income from Investments in Unconsolidated Affiliates [Member] \| Net of tax [Member]
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI for Other Comprehensive Income Attributable to Unconsolidated Affiliates, Net of Tax	(46)			40			26	55
AOCI [Member]
Other Comprehensive Income (Loss), Net of Tax	(84,708)	$ (66,872)	$ (81,285)	20,451	$ (3,897)	$ 51,939	(232,865)
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Net	11,625			(25,013)			38,402	(56,359)
Cash Flow Hedging [Member] \| Commodity contracts
Unrealized Gain Loss On Cash Flow Hedges Net Of Tax Accumulated Other Comprehensive Income Loss	30,258						30,258
Cash Flow Hedging [Member] \| Interest Rate Contract [Member]
Amount of accumulated other comprehensive income (loss) attributable primarily to settled interest-rate swaps.	(111,275)						(111,275)
Cash Flow Hedging [Member] \| Forward Contracts [Member]
Amount of accumulated other comprehensive income (loss) attributable primarily to forward starting interest-rate swaps.	$ (213,186)						$ (213,186)
Cash Flow Hedging [Member] \| Sales [Member] \| Commodity contracts
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Net				(20,630)				(42,430)
Cash Flow Hedging [Member] \| Interest Expense [Member] \| Interest Rate Contract [Member]
Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Net				$ (4,383)				$ (13,929)

EARNINGS PER SHARE EARNINGS P_3

EARNINGS PER SHARE EARNINGS PER SHARE (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Basic EPS
Net income available for common stock	$ 308,880	$ 312,984	$ 957,501	$ 857,990
Shares	413,816	412,117	413,443	411,400
Earnings per share, basic	$ 0.75	$ 0.76	$ 2.32	$ 2.09
Diluted EPS
Effect of dilutive securities	$ 0	$ 0	$ 0	$ 0
Effect of dilutive securities, number of shares	1,762	2,730	1,834	2,635
Net income attributable to ONEOK available for common stock and common stock equivalents	$ 308,880	$ 312,984	$ 957,501	$ 857,990
Shares	415,578	414,847	415,277	414,035
Earnings per share, diluted	$ 0.74	$ 0.75	$ 2.31	$ 2.07

EMPLOYEE BENEFIT PLANS EMPLOY_3

EMPLOYEE BENEFIT PLANS EMPLOYEE BENEFIT PLANS (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Retirement Benefits
Components of net periodic benefit cost
Service cost	$ 1,954	$ 1,832	$ 5,862	$ 5,496
Interest cost	5,126	4,408	15,378	13,224
Expected return on plan assets	(5,892)	(5,969)	(17,676)	(17,907)
Amortization of net loss	3,158	4,258	9,474	12,774
Net periodic benefit cost (income)	4,346	4,529	13,038	13,587
Other Postretirement Benefits Plan
Components of net periodic benefit cost
Service cost	117	211	351	633
Interest cost	509	527	1,527	1,581
Expected return on plan assets	(570)	(672)	(1,710)	(2,016)
Amortization of prior service credit	(57)	(415)	(171)	(1,245)
Amortization of net loss	74	334	222	1,002
Net periodic benefit cost (income)	$ 73	$ (15)	$ 219	$ (45)

UNCONSOLIDATED AFFILIATES (Deta

UNCONSOLIDATED AFFILIATES (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Schedule of Equity Method Investments [Line Items]
Equity in net earnings from investments	$ 37,576	$ 39,313	$ 115,175	$ 116,070
Accounts Payable, Related Parties, Current	13,800		13,800		$ 14,700
Income Statement [Abstract]
Revenues	151,210	160,962	471,461	471,641
Operating expenses	69,783	69,004	217,287	205,525
Net income	74,341	85,361	234,154	247,754
Distributions paid to us	44,357	47,197	203,347	145,437
Unconsolidated Affiliates [Member]
Schedule of Equity Method Investments [Line Items]
Related Party Transaction, Expenses from Transactions with Related Parties	41,900	37,500	124,200	113,200
Northern Border Pipeline
Schedule of Equity Method Investments [Line Items]
Equity in net earnings from investments	16,102	16,486	50,593	48,863
Income Statement [Abstract]
Distributions paid to us			50,000
Overland Pass Pipeline
Schedule of Equity Method Investments [Line Items]
Equity in net earnings from investments	15,481	16,081	48,340	48,714
Roadrunner
Schedule of Equity Method Investments [Line Items]
Equity in net earnings from investments	7,421	6,303	19,836	16,803
Other Unconsolidated Affiliates
Schedule of Equity Method Investments [Line Items]
Equity in net earnings from investments	$ (1,428)	$ 443	$ (3,594)	$ 1,690

LEASES Leases (Details)

LEASES Leases (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
LEASES Leases (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Sep. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Lessee, Lease, Details [Line Items]
Operating cash flows for operating leases		$ 4,972
Financing cash flows for finance lease		1,307
Right-of-use asset obtained in exchange for operating lease liability		3,663
Finance lease assets- Accumulated depreciation	$ (3,585,411)	(3,585,411)		$ (3,264,312)
Finance lease liability - current	1,901	1,901		1,765
Finance lease liability - noncurrent	24,801	24,801		$ 26,244
Lease Assets and Liabilities Included in the Consolidated Balance Sheet
Lessee, Lease, Details [Line Items]
Operating lease assets- Other assets	16,176	16,176
Finance lease assets- PPE	28,286	28,286
Finance lease assets- Accumulated depreciation	(1,037)	(1,037)
Total leased assets	43,425	43,425
Operating lease liabilities- Other current liabilities	2,624	2,624
Finance lease liability - current	1,901	1,901
Operating lease liabilities- Other deferred credits	13,790	13,790
Finance lease liability - noncurrent	24,801	24,801
Total lease liabilities	43,116	43,116
Components of Lease Cost
Lessee, Lease, Details [Line Items]
Operating leases - Operations and maintenance	1,751	5,402
Finance lease - Amortization of lease assets	283	849
Finance lease - Interest on lease liabilities	675	2,058
Total lease cost	$ 2,709	$ 8,309
Weighted-Average Remaining Lease Term
Lessee, Lease, Details [Line Items]
Operating leases	10 years 1 month 6 days	10 years 1 month 6 days
Finance lease	9 years 1 month 6 days	9 years 1 month 6 days
Weighted-Average Discount Rate
Lessee, Lease, Details [Line Items]
Operating leases	4.58%	4.58%
Finance lease	10.00%	10.00%
Maturity of Finance Lease Liability
Lessee, Lease, Details [Line Items]
Remainder of 2019	$ 1,100	$ 1,100
2020	4,500	4,500
2021	4,500	4,500
2022	4,500	4,500
2023	4,500	4,500
2024 and beyond	21,600	21,600
Total lease payments	40,700	40,700
Less: Interest	14,000	14,000
Present value of lease liabilities	26,700	26,700
Maturity of Operating Lease Liabilities
Lessee, Lease, Details [Line Items]
Remainder of 2019	1,300	1,300
2020	2,400	2,400
2021	2,000	2,000
2022	2,000	2,000
2023	1,900	1,900
2024 and beyond	11,100	11,100
Total lease payments	20,700	20,700
Less: Interest	4,300	4,300
Present value of lease liabilities	$ 16,400	$ 16,400
Accounting Standards Update 2016-02
Lessee, Lease, Details [Line Items]
Present value of lease liabilities			$ 17,400
Operating lease assets- Other assets			$ 17,500

REVENUE REVENUE (Details)

REVENUE REVENUE (Details) - USD ($)	9 Months Ended
REVENUE REVENUE (Details) - USD ($)	Sep. 30, 2019	Dec. 31, 2018
Contract with Customer, Asset and Liability [Abstract]
Contract with customer, asset	$ 6,100,000	$ 6,200,000
Amounts invoiced in excess of revenue recognized	(900,000)
Net additions, asset	800,000
Contract with customer, asset, net, current	2,400,000	1,700,000
Contract with customer, asset, net, noncurrent	3,700,000	4,500,000
Contract with customer, liability	45,400,000	31,700,000
Revenue recognized included in beginning balance	(15,200,000)
Net additions, liability	28,900,000
Contract with customer, liability, current	25,200,000	15,600,000
Contract with customer, liability, noncurrent	20,200,000	$ 16,100,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	1,904,200,000
2019 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	101,500,000
2020 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	335,600,000
2021 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	286,300,000
2022 [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	228,300,000
Thereafter [Member]
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction [Line Items]
Revenue, Remaining Performance Obligation, Amount	$ 952,500,000

SEGMENTS (Details)

SEGMENTS (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
SEGMENTS (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018	Dec. 31, 2018
Segment disclosure [Abstract]
Revenues	$ 2,263,228			$ 3,393,890			$ 7,500,761	$ 9,456,496
Cost of sales and fuel (exclusive of depreciation and operating costs)	(1,414,528)			(2,560,765)			(4,996,699)	(7,104,609)
Operating costs	(245,135)			(230,371)			(723,589)	(670,728)
Equity in net earnings (loss) from investments	37,576			39,313			115,175	116,070
Depreciation and amortization	(121,430)			(107,383)			(350,552)	(317,908)
Total assets	21,335,907			17,911,314			21,335,907	17,911,314	$ 18,231,671
Capital expenditures	1,019,174			694,303			2,739,338	1,309,655
Net income	309,155	$ 311,963	$ 337,208	313,916	$ 282,179	$ 266,049	958,326	862,144
Interest Expense	129,577			121,910			362,490	351,131
Income taxes	97,365			102,983			274,234	266,285
Noncash compensation expense	9,757			5,829			20,412	27,195
Other corporate costs and noncash items	(20,711)			(3,290)			(48,981)	(5,384)
Natural Gas Gathering And Processing [Member]
Segment disclosure [Abstract]
Revenues	476,212			791,255			1,753,053	2,200,175
Cost of sales and fuel (exclusive of depreciation and operating costs)	(210,739)			(542,463)			(971,397)	(1,478,044)
Operating costs	(91,227)			(90,970)			(271,236)	(272,931)
Equity in net earnings (loss) from investments	(1,837)			74			(4,660)	948
Noncash compensation expense and other	2,883			1,703			8,399	6,868
Segment adjusted EBITDA	175,292			159,599			514,159	457,016
Depreciation and amortization	(55,781)			(49,223)			(162,014)	(145,120)
Total assets	6,546,417			5,811,140			6,546,417	5,811,140
Capital expenditures	245,745			213,034			674,115	433,605
Natural Gas Gathering And Processing [Member] \| Natural Gas Gathering and Processing Intersegment [Member]
Segment disclosure [Abstract]
Revenues	244,200			519,700			897,900	1,400,000
Natural Gas Liquids [Member]
Segment disclosure [Abstract]
Revenues	1,900,507			3,026,288			6,284,565	8,332,687
Cost of sales and fuel (exclusive of depreciation and operating costs)	(1,438,206)			(2,544,854)			(4,914,452)	(7,009,438)
Operating costs	(114,903)			(101,126)			(340,274)	(289,328)
Equity in net earnings (loss) from investments	15,890			16,450			49,406	49,456
Noncash compensation expense and other	4,174			2,268			12,618	9,789
Segment adjusted EBITDA	367,462			399,026			1,091,863	1,093,166
Depreciation and amortization	(50,419)			(43,688)			(143,166)	(128,993)
Total assets	11,662,489			9,632,212			11,662,489	9,632,212
Capital expenditures	738,038			444,780			1,969,138	786,635
Natural Gas Liquids [Member] \| Natural Gas Liquids Regulated [Member]
Segment disclosure [Abstract]
Revenues	379,700			316,000			1,000,000	910,300
Cost of sales and fuel (exclusive of depreciation and operating costs)	(129,500)			(132,700)			(364,900)	(379,500)
Natural Gas Pipelines [Member]
Segment disclosure [Abstract]
Revenues	121,548			105,194			355,479	314,897
Cost of sales and fuel (exclusive of depreciation and operating costs)	(381)			(2,384)			(3,785)	(10,475)
Operating costs	(40,170)			(36,543)			(113,043)	(104,692)
Equity in net earnings (loss) from investments	23,523			22,789			70,429	65,666
Noncash compensation expense and other	(701)			1,050			1,931	3,701
Segment adjusted EBITDA	103,819			90,106			311,011	269,097
Depreciation and amortization	(14,330)			(13,625)			(42,653)	(41,320)
Total assets	2,083,773			2,109,897			2,083,773	2,109,897
Capital expenditures	27,767			31,522			77,861	71,897
Natural Gas Pipelines [Member] \| Natural Gas Pipelines Regulated [Member]
Segment disclosure [Abstract]
Revenues	72,300			65,900			214,700	198,400
Cost of sales and fuel (exclusive of depreciation and operating costs)	(5,100)			(5,500)			(14,400)	(20,400)
Total Segments [Member]
Segment disclosure [Abstract]
Revenues	2,498,267			3,922,737			8,393,097	10,847,759
Cost of sales and fuel (exclusive of depreciation and operating costs)	(1,649,326)			(3,089,701)			(5,889,634)	(8,497,957)
Operating costs	(246,300)			(228,639)			(724,553)	(666,951)
Equity in net earnings (loss) from investments	37,576			39,313			115,175	116,070
Noncash compensation expense and other	6,356			5,021			22,948	20,358
Segment adjusted EBITDA	646,573			648,731			1,917,033	1,819,279
Depreciation and amortization	(120,530)			(106,536)			(347,833)	(315,433)
Total assets	20,292,679			17,553,249			20,292,679	17,553,249
Capital expenditures	1,011,550			689,336			2,721,114	1,292,137
Other and Eliminations
Segment disclosure [Abstract]
Revenues	(235,039)			(528,847)			(892,336)	(1,391,263)
Cost of sales and fuel (exclusive of depreciation and operating costs)	234,798			528,936			892,935	1,393,348
Operating costs	1,165			(1,732)			964	(3,777)
Equity in net earnings (loss) from investments	0			0			0	0
Depreciation and amortization	(900)			(847)			(2,719)	(2,475)
Total assets	1,043,228			358,065			1,043,228	358,065
Capital expenditures	7,624			4,967			18,224	17,518
Operating Segments [Member] \| Natural Gas Liquids [Member] \| Natural Gas Liquids Regulated [Member]
Segment disclosure [Abstract]
Revenues	315,700			276,400			853,000	784,800
Noncustomer [Domain]
Segment disclosure [Abstract]
Revenues	89,000			(17,700)			129,900	(32,100)
NGL and Condensate Sales [Member]
Segment disclosure [Abstract]
Revenues	1,761,482			2,836,661			5,837,360	7,862,478
NGL and Condensate Sales [Member] \| Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	244,932			501,163			890,021	1,362,159
NGL and Condensate Sales [Member] \| Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,746,630			2,861,896			5,826,297	7,884,183
NGL and Condensate Sales [Member] \| Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0			0			0	0
NGL and Condensate Sales [Member] \| Total Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	1,991,562			3,363,059			6,716,318	9,246,342
NGL and Condensate Sales [Member] \| Other and Eliminations
Segment disclosure [Abstract]
Revenues	(230,080)			(526,398)			(878,958)	(1,383,864)
Residue Natural Gas Sales [Member]
Segment disclosure [Abstract]
Revenues	184,967			246,237			726,347	714,172
Residue Natural Gas Sales [Member] \| Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	185,303			245,474			725,672	709,089
Residue Natural Gas Sales [Member] \| Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0			0			0	0
Residue Natural Gas Sales [Member] \| Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	231			763			1,242	5,861
Residue Natural Gas Sales [Member] \| Total Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	185,534			246,237			726,914	714,950
Residue Natural Gas Sales [Member] \| Other and Eliminations
Segment disclosure [Abstract]
Revenues	(567)			0			(567)	(778)
Gathering, Processing and Exchange Services Revenue
Segment disclosure [Abstract]
Revenues	147,974			157,934			435,644	418,871
Gathering, Processing and Exchange Services Revenue \| Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	42,795			41,101			126,073	122,331
Gathering, Processing and Exchange Services Revenue \| Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	105,179			116,833			309,571	296,561
Gathering, Processing and Exchange Services Revenue \| Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0			0			0	0
Gathering, Processing and Exchange Services Revenue \| Total Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	147,974			157,934			435,644	418,892
Gathering, Processing and Exchange Services Revenue \| Other and Eliminations
Segment disclosure [Abstract]
Revenues	0			0			0	(21)
Transportation and Storage Revenue [Member]
Segment disclosure [Abstract]
Revenues	152,197			140,912			451,361	426,428
Transportation and Storage Revenue [Member] \| Natural Gas Gathering And Processing [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	0			0			0	0
Transportation and Storage Revenue [Member] \| Natural Gas Liquids [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	46,407			45,251			141,384	143,741
Transportation and Storage Revenue [Member] \| Natural Gas Pipelines [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	108,384			98,031			317,555	289,646
Transportation and Storage Revenue [Member] \| Total Segments [Member]
Segment Reporting Information [Line Items]
Revenue from Contract with Customer, Excluding Assessed Tax	154,791			143,282			458,939	433,387
Transportation and Storage Revenue [Member] \| Other and Eliminations
Segment disclosure [Abstract]
Revenues	(2,594)			(2,370)			(7,578)	(6,959)
Other [Member]
Segment disclosure [Abstract]
Revenues	16,608			12,146			50,049	34,547
Other [Member] \| Natural Gas Gathering And Processing [Member]
Segment disclosure [Abstract]
Revenues	3,182			3,517			11,287	6,596
Other [Member] \| Natural Gas Liquids [Member]
Segment disclosure [Abstract]
Revenues	2,291			2,308			7,313	8,202
Other [Member] \| Natural Gas Pipelines [Member]
Segment disclosure [Abstract]
Revenues	12,933			6,400			36,682	19,390
Other [Member] \| Total Segments [Member]
Segment disclosure [Abstract]
Revenues	18,406			12,225			55,282	34,188
Other [Member] \| Other and Eliminations
Segment disclosure [Abstract]
Revenues	$ (1,798)			$ (79)			$ (5,233)	$ 359

SUPPLEMENTAL CONDENSED CONSOL_3

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION, Income Statement and Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Sep. 30, 2019	Sep. 30, 2018
Condensed Financial Statements, Captions [Line Items]
Revenues	$ 2,263,228			$ 3,393,890			$ 7,500,761	$ 9,456,496
Cost of sales and fuel (exclusive of items shown separately below)	1,414,528			2,560,765			4,996,699	7,104,609
(Gain) loss on sale of assets	(16)			(163)			2,882	(348)
Operating income	482,151			495,534			1,427,039	1,363,599
Equity in net earnings from investments	37,576			39,313			115,175	116,070
Interest expense, net	(129,577)			(121,910)			(362,490)	(351,131)
Income before income taxes	406,520			416,899			1,232,560	1,128,429
Income taxes	(97,365)			(102,983)			(274,234)	(266,285)
Net income	309,155	$ 311,963	$ 337,208	313,916	$ 282,179	$ 266,049	958,326	862,144
Less: Net income attributable to noncontrolling interests	0			657			0	3,329
Net income attributable to ONEOK	309,155			313,259			958,326	858,815
Less: Preferred stock dividends	275			275			825	825
Net income available to common shareholders	308,880			312,984			957,501	857,990
Other comprehensive income (loss), net of tax	(84,708)	$ (66,872)	$ (81,285)	20,451	$ (3,897)	$ 51,939	(232,865)	68,493
Comprehensive income	224,447			334,367			725,461	930,637
Less: Comprehensive income attributable to noncontrolling interest	0			657			0	3,329
Comprehensive income attributable to ONEOK	$ 224,447			333,710			$ 725,461	927,308
Northern Border Pipeline
Condensed Financial Statements, Captions [Line Items]
Equity Method Investment, Ownership Percentage	50.00%						50.00%
Equity in net earnings from investments	$ 16,102			16,486			$ 50,593	48,863
Commodity Sales
Condensed Financial Statements, Captions [Line Items]
Revenues	1,947,834			3,083,625			6,567,634	8,578,891
Services
Condensed Financial Statements, Captions [Line Items]
Revenues	315,394			310,265			933,127	877,605
Reportable Legal Entities \| Parent Issuer & Guarantor
Condensed Financial Statements, Captions [Line Items]
Revenues	0			0			0	0
Cost of sales and fuel (exclusive of items shown separately below)	0			0			0	0
Operating expenses	(700)			2,000			(700)	3,300
(Gain) loss on sale of assets	0			0			0	0
Operating income	700			(2,000)			700	(3,300)
Equity in net earnings from investments	470,200			457,300			1,392,900	1,226,600
Other income (expense), net	11,100			9,300			26,300	23,100
Interest expense, net	(78,400)			(49,100)			(198,100)	(129,200)
Income before income taxes	403,600			415,500			1,221,800	1,117,200
Income taxes	(94,400)			(102,300)			(263,500)	(258,400)
Net income	309,200			313,200			958,300	858,800
Less: Net income attributable to noncontrolling interests				0				0
Net income attributable to ONEOK				313,200				858,800
Less: Preferred stock dividends	300			200			800	800
Net income available to common shareholders	308,900			313,000			957,500	858,000
Other comprehensive income (loss), net of tax	(94,400)			23,400			(226,000)	65,600
Comprehensive income	214,800			336,600			732,300	924,400
Less: Comprehensive income attributable to noncontrolling interest				0				0
Comprehensive income attributable to ONEOK				336,600				924,400
Reportable Legal Entities \| Parent Issuer & Guarantor \| Commodity Sales
Condensed Financial Statements, Captions [Line Items]
Revenues	0			0			0	0
Reportable Legal Entities \| Parent Issuer & Guarantor \| Services
Condensed Financial Statements, Captions [Line Items]
Revenues	0			0			0	0
Reportable Legal Entities \| Subsidiary Issuer & Guarantor
Condensed Financial Statements, Captions [Line Items]
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
(Gain) loss on sale of assets	0			0			0	0
Operating income	0			0			0	0
Equity in net earnings from investments	476,100			457,100			1,405,600	1,231,200
Other income (expense), net	75,400			80,300			232,800	234,900
Interest expense, net	(78,100)			(80,300)			(235,500)	(234,900)
Income before income taxes	473,400			457,100			1,402,900	1,231,200
Income taxes	0			0			0	0
Net income	473,400			457,100			1,402,900	1,231,200
Less: Net income attributable to noncontrolling interests				0				0
Net income attributable to ONEOK				457,100				1,231,200
Less: Preferred stock dividends	0			0			0	0
Net income available to common shareholders	473,400			457,100			1,402,900	1,231,200
Other comprehensive income (loss), net of tax	12,400			(3,700)			(9,000)	4,000
Comprehensive income	485,800			453,400			1,393,900	1,235,200
Less: Comprehensive income attributable to noncontrolling interest				0				0
Comprehensive income attributable to ONEOK				453,400				1,235,200
Reportable Legal Entities \| Subsidiary Issuer & Guarantor \| Commodity Sales
Condensed Financial Statements, Captions [Line Items]
Revenues	0			0			0	0
Reportable Legal Entities \| Subsidiary Issuer & Guarantor \| Services
Condensed Financial Statements, Captions [Line Items]
Revenues	0			0			0	0
Reportable Legal Entities \| Guarantor Subsidiary
Condensed Financial Statements, Captions [Line Items]
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
(Gain) loss on sale of assets	100			0			2,700	0
Operating income	(100)			0			(2,700)	0
Equity in net earnings from investments	476,200			457,100			1,408,300	1,231,200
Other income (expense), net	78,100			80,300			235,500	234,900
Interest expense, net	(78,100)			(80,300)			(235,500)	(234,900)
Income before income taxes	476,100			457,100			1,405,600	1,231,200
Income taxes	0			0			0	0
Net income	476,100			457,100			1,405,600	1,231,200
Less: Net income attributable to noncontrolling interests				0				0
Net income attributable to ONEOK				457,100				1,231,200
Less: Preferred stock dividends	0			0			0	0
Net income available to common shareholders	476,100			457,100			1,405,600	1,231,200
Other comprehensive income (loss), net of tax	7,900			(8,100)			(22,500)	(6,900)
Comprehensive income	484,000			449,000			1,383,100	1,224,300
Less: Comprehensive income attributable to noncontrolling interest				0				0
Comprehensive income attributable to ONEOK				449,000				1,224,300
Reportable Legal Entities \| Guarantor Subsidiary \| Commodity Sales
Condensed Financial Statements, Captions [Line Items]
Revenues	0			0			0	0
Reportable Legal Entities \| Guarantor Subsidiary \| Services
Condensed Financial Statements, Captions [Line Items]
Revenues	0			0			0	0
Reportable Legal Entities \| Combined Non-Guarantor Subsidiaries
Condensed Financial Statements, Captions [Line Items]
Revenues	2,263,800			3,394,400			7,502,400	9,458,000
Cost of sales and fuel (exclusive of items shown separately below)	1,414,500			2,560,800			4,996,700	7,104,600
Operating expenses	367,800			336,300			1,076,500	986,800
(Gain) loss on sale of assets	(100)			(200)			200	(300)
Operating income	481,600			497,500			1,429,000	1,366,900
Equity in net earnings from investments	29,100			30,100			87,100	86,200
Other income (expense), net	8,000			(5,300)			29,300	(23,300)
Interest expense, net	(51,200)			(72,800)			(164,400)	(221,900)
Income before income taxes	467,500			449,500			1,381,000	1,207,900
Income taxes	(3,000)			(700)			(10,800)	(7,900)
Net income	464,500			448,800			1,370,200	1,200,000
Less: Net income attributable to noncontrolling interests				700				3,300
Net income attributable to ONEOK				448,100				1,196,700
Less: Preferred stock dividends	0			0			0	0
Net income available to common shareholders	464,500			448,100			1,370,200	1,196,700
Other comprehensive income (loss), net of tax	5,000			(7,300)			(20,600)	(8,000)
Comprehensive income	469,500			441,500			1,349,600	1,192,000
Less: Comprehensive income attributable to noncontrolling interest				700				3,300
Comprehensive income attributable to ONEOK				440,800				1,188,700
Reportable Legal Entities \| Combined Non-Guarantor Subsidiaries \| Commodity Sales
Condensed Financial Statements, Captions [Line Items]
Revenues	1,947,800			3,083,600			6,567,600	8,578,900
Reportable Legal Entities \| Combined Non-Guarantor Subsidiaries \| Services
Condensed Financial Statements, Captions [Line Items]
Revenues	316,000			310,800			934,800	879,100
Reportable Legal Entities \| Total
Condensed Financial Statements, Captions [Line Items]
Revenues	2,263,200			3,393,900			7,500,800	9,456,500
Cost of sales and fuel (exclusive of items shown separately below)	1,414,500			2,560,800			4,996,700	7,104,600
Operating expenses	366,500			337,800			1,074,200	988,600
(Gain) loss on sale of assets	0			(200)			2,900	(300)
Operating income	482,200			495,500			1,427,000	1,363,600
Equity in net earnings from investments	37,600			39,300			115,200	116,100
Other income (expense), net	16,400			4,000			52,900	(200)
Interest expense, net	(129,600)			(121,900)			(362,500)	(351,100)
Income before income taxes	406,600			416,900			1,232,600	1,128,400
Income taxes	(97,400)			(103,000)			(274,300)	(266,300)
Net income	309,200			313,900			958,300	862,100
Less: Net income attributable to noncontrolling interests				700				3,300
Net income attributable to ONEOK				313,200				858,800
Less: Preferred stock dividends	300			200			800	800
Net income available to common shareholders	308,900			313,000			957,500	858,000
Other comprehensive income (loss), net of tax	(84,700)			20,500			(232,800)	68,500
Comprehensive income	224,500			334,400			725,500	930,600
Less: Comprehensive income attributable to noncontrolling interest				700				3,300
Comprehensive income attributable to ONEOK				333,700				927,300
Reportable Legal Entities \| Total \| Commodity Sales
Condensed Financial Statements, Captions [Line Items]
Revenues	1,947,800			3,083,600			6,567,600	8,578,900
Reportable Legal Entities \| Total \| Services
Condensed Financial Statements, Captions [Line Items]
Revenues	315,400			310,300			933,200	877,600
Consolidating Entries
Condensed Financial Statements, Captions [Line Items]
Revenues	(600)			(500)			(1,600)	(1,500)
Cost of sales and fuel (exclusive of items shown separately below)	0			0			0	0
Operating expenses	(600)			(500)			(1,600)	(1,500)
(Gain) loss on sale of assets	0			0			0	0
Operating income	0			0			0	0
Equity in net earnings from investments	(1,414,000)			(1,362,300)			(4,178,700)	(3,659,100)
Other income (expense), net	(156,200)			(160,600)			(471,000)	(469,800)
Interest expense, net	156,200			160,600			471,000	469,800
Income before income taxes	(1,414,000)			(1,362,300)			(4,178,700)	(3,659,100)
Income taxes	0			0			0	0
Net income	(1,414,000)			(1,362,300)			(4,178,700)	(3,659,100)
Less: Net income attributable to noncontrolling interests				0				0
Net income attributable to ONEOK				(1,362,300)				(3,659,100)
Less: Preferred stock dividends	0			0			0	0
Net income available to common shareholders	(1,414,000)			(1,362,300)			(4,178,700)	(3,659,100)
Other comprehensive income (loss), net of tax	(15,600)			16,200			45,300	13,800
Comprehensive income	(1,429,600)			(1,346,100)			(4,133,400)	(3,645,300)
Less: Comprehensive income attributable to noncontrolling interest				0				0
Comprehensive income attributable to ONEOK				(1,346,100)				(3,645,300)
Consolidating Entries \| Commodity Sales
Condensed Financial Statements, Captions [Line Items]
Revenues	0			0			0	0
Consolidating Entries \| Services
Condensed Financial Statements, Captions [Line Items]
Revenues	$ (600)			$ (500)			$ (1,600)	$ (1,500)

SUPPLEMENTAL CONDENSED CONSOL_4

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION, Balance Sheet (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2017
Current assets
Cash and cash equivalents	$ 673,309	$ 11,975	$ 84,464		$ 37,193
Accounts receivable, net	718,708	818,958
Materials and supplies	192,933	141,174
Natural gas and NGLs in storage	283,545	296,667
Other current assets	79,763	100,808
Total current assets	1,967,585	1,398,632
Property, plant and equipment
Property, plant and equipment	20,948,267	18,030,963
Accumulated depreciation and amortization	3,585,411	3,264,312
Net property, plant and equipment	17,362,856	14,766,651
Investments and other assets
Investments	870,511	969,150
Other assets	174,147	130,096
Total investments and other assets	2,005,466	2,066,388
Total assets	21,335,907	18,231,671	17,911,314
Current liabilities
Current maturities of long-term debt	7,650	507,650
Accounts payable	1,129,849	1,116,337
Other current liabilities	123,146	149,773
Total current liabilities	1,567,152	2,108,436
Long-term debt, excluding current maturities	12,479,452	8,873,334
Deferred credits and other liabilities
Deferred income taxes	418,736	219,731
Other deferred credits	626,860	424,383
Total deferred credits and other liabilities	1,070,397	670,358
Commitments and contingencies
Equity
Equity	6,218,906	6,579,543	6,652,758	$ 6,838,483
Total liabilities and equity	21,335,907	18,231,671
Reportable Legal Entities \| Parent Issuer & Guarantor
Current assets
Cash and cash equivalents	673,300	12,000	84,500		37,200
Accounts receivable, net	0	0
Materials and supplies	0	0
Natural gas and NGLs in storage	0	0
Other current assets	12,300	29,100
Total current assets	685,600	41,100
Property, plant and equipment
Property, plant and equipment	160,000	145,500
Accumulated depreciation and amortization	97,600	92,000
Net property, plant and equipment	62,400	53,500
Investments and other assets
Investments	6,554,500	6,153,500
Intercompany receivable	8,099,100	5,308,600
Other assets	134,800	115,900
Total investments and other assets	14,788,400	11,578,000
Total assets	15,536,400	11,672,600
Current liabilities
Current maturities of long-term debt	0	0
Accounts payable	9,500	31,300
Other current liabilities	96,400	123,200
Total current liabilities	105,900	154,500
Intercompany payable	0	0
Long-term debt, excluding current maturities	8,419,600	4,510,700
Deferred credits and other liabilities
Deferred income taxes	297,900	112,300
Other deferred credits	494,100	315,600
Total deferred credits and other liabilities	792,000	427,900
Commitments and contingencies
Equity
Equity	6,218,900	6,579,500
Total liabilities and equity	15,536,400	11,672,600
Reportable Legal Entities \| Subsidiary Issuer & Guarantor
Current assets
Cash and cash equivalents	0	0	0		0
Accounts receivable, net	0	0
Materials and supplies	0	0
Natural gas and NGLs in storage	0	0
Other current assets	0	0
Total current assets	0	0
Property, plant and equipment
Property, plant and equipment	0	0
Accumulated depreciation and amortization	0	0
Net property, plant and equipment	0	0
Investments and other assets
Investments	3,932,200	3,548,100
Intercompany receivable	6,897,700	7,701,500
Other assets	0	0
Total investments and other assets	10,829,900	11,249,600
Total assets	10,829,900	11,249,600
Current liabilities
Current maturities of long-term debt	0	500,000
Accounts payable	0	0
Other current liabilities	63,500	81,000
Total current liabilities	63,500	581,000
Intercompany payable	0	0
Long-term debt, excluding current maturities	4,044,300	4,341,400
Deferred credits and other liabilities
Deferred income taxes	0	0
Other deferred credits	0	0
Total deferred credits and other liabilities	0	0
Commitments and contingencies
Equity
Equity	6,722,100	6,327,200
Total liabilities and equity	10,829,900	11,249,600
Reportable Legal Entities \| Guarantor Subsidiary
Current assets
Cash and cash equivalents	0	0	0		0
Accounts receivable, net	0	0
Materials and supplies	0	0
Natural gas and NGLs in storage	0	0
Other current assets	0	0
Total current assets	0	0
Property, plant and equipment
Property, plant and equipment	0	0
Accumulated depreciation and amortization	0	0
Net property, plant and equipment	0	0
Investments and other assets
Investments	10,986,900	9,721,600
Intercompany receivable	0	1,528,000
Other assets	0	0
Total investments and other assets	10,986,900	11,249,600
Total assets	10,986,900	11,249,600
Current liabilities
Current maturities of long-term debt	0	0
Accounts payable	0	0
Other current liabilities	0	0
Total current liabilities	0	0
Intercompany payable	7,054,700	7,701,500
Long-term debt, excluding current maturities	0	0
Deferred credits and other liabilities
Deferred income taxes	0	0
Other deferred credits	0	0
Total deferred credits and other liabilities	0	0
Commitments and contingencies
Equity
Equity	3,932,200	3,548,100
Total liabilities and equity	10,986,900	11,249,600
Reportable Legal Entities \| Combined Non-Guarantor Subsidiaries
Current assets
Cash and cash equivalents	0	0	0		0
Accounts receivable, net	718,700	819,000
Materials and supplies	192,900	141,200
Natural gas and NGLs in storage	283,500	296,700
Other current assets	86,800	100,600
Total current assets	1,281,900	1,357,500
Property, plant and equipment
Property, plant and equipment	20,788,300	17,885,500
Accumulated depreciation and amortization	3,487,800	3,172,300
Net property, plant and equipment	17,300,500	14,713,200
Investments and other assets
Investments	770,600	791,100
Intercompany receivable	0	0
Other assets	1,001,100	982,300
Total investments and other assets	1,771,700	1,773,400
Total assets	20,354,100	17,844,100
Current liabilities
Current maturities of long-term debt	7,700	7,700
Accounts payable	1,120,300	1,085,000
Other current liabilities	269,700	280,200
Total current liabilities	1,397,700	1,372,900
Intercompany payable	7,942,100	6,836,600
Long-term debt, excluding current maturities	15,600	21,200
Deferred credits and other liabilities
Deferred income taxes	121,700	108,400
Other deferred credits	157,600	135,200
Total deferred credits and other liabilities	279,300	243,600
Commitments and contingencies
Equity
Equity	10,719,400	9,369,800
Total liabilities and equity	20,354,100	17,844,100
Reportable Legal Entities \| Total
Current assets
Cash and cash equivalents	673,300	12,000	84,500		37,200
Accounts receivable, net	718,700	819,000
Materials and supplies	192,900	141,200
Natural gas and NGLs in storage	283,500	296,700
Other current assets	99,100	129,700
Total current assets	1,967,500	1,398,600
Property, plant and equipment
Property, plant and equipment	20,948,300	18,031,000
Accumulated depreciation and amortization	3,585,400	3,264,300
Net property, plant and equipment	17,362,900	14,766,700
Investments and other assets
Investments	870,500	969,200
Intercompany receivable	0	0
Other assets	1,135,000	1,097,200
Total investments and other assets	2,005,500	2,066,400
Total assets	21,335,900	18,231,700
Current liabilities
Current maturities of long-term debt	7,700	507,700
Accounts payable	1,129,800	1,116,300
Other current liabilities	429,600	484,400
Total current liabilities	1,567,100	2,108,400
Intercompany payable	0	0
Long-term debt, excluding current maturities	12,479,500	8,873,300
Deferred credits and other liabilities
Deferred income taxes	418,700	219,700
Other deferred credits	651,700	450,800
Total deferred credits and other liabilities	1,070,400	670,500
Commitments and contingencies
Equity
Equity	6,218,900	6,579,500
Total liabilities and equity	21,335,900	18,231,700
Consolidating Entries
Current assets
Cash and cash equivalents	0	0	$ 0		$ 0
Accounts receivable, net	0	0
Materials and supplies	0	0
Natural gas and NGLs in storage	0	0
Other current assets	0	0
Total current assets	0	0
Property, plant and equipment
Property, plant and equipment	0	0
Accumulated depreciation and amortization	0	0
Net property, plant and equipment	0	0
Investments and other assets
Investments	(21,373,700)	(19,245,100)
Intercompany receivable	(14,996,800)	(14,538,100)
Other assets	(900)	(1,000)
Total investments and other assets	(36,371,400)	(33,784,200)
Total assets	(36,371,400)	(33,784,200)
Current liabilities
Current maturities of long-term debt	0	0
Accounts payable	0	0
Other current liabilities	0	0
Total current liabilities	0	0
Intercompany payable	(14,996,800)	(14,538,100)
Long-term debt, excluding current maturities	0	0
Deferred credits and other liabilities
Deferred income taxes	(900)	(1,000)
Other deferred credits	0	0
Total deferred credits and other liabilities	(900)	(1,000)
Commitments and contingencies
Equity
Equity	(21,373,700)	(19,245,100)
Total liabilities and equity	$ (36,371,400)	$ (33,784,200)

SUPPLEMENTAL CONDENSED CONSOL_5

SUPPLEMENTAL CONDENSED CONSOLIDATING FINANCIAL INFORMATION, Cash Flows (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Operating activities
Cash provided by operating activities			$ 1,326,845	$ 1,516,450
Investing activities
Capital expenditures	$ (1,019,174)	$ (694,303)	(2,739,338)	(1,309,655)
Contributions to unconsolidated affiliates			(3,290)	(831)
Other investing activities			12,583	1,053
Cash used in investing activities			(2,647,874)	(1,289,820)
Financing activities
Dividends paid			(1,079,379)	(983,068)
Distributions to noncontrolling interests			0	(3,500)
Borrowing (repayment) of short-term borrowings, net			0	(494,673)
Issuance of long-term debt, net of discounts			4,185,435	1,245,773
Payments of Financing Costs			29,777	11,301
Repayment of long-term debt			(1,055,436)	(930,738)
Issuance of common stock			19,333	1,195,128
Acquisition of noncontrolling interests			0	(195,000)
Other, net			(57,813)	(1,980)
Cash provided by (used in) financing activities			1,982,363	(179,359)
Change in cash and cash equivalents			661,334	47,271
Cash and cash equivalents at beginning of period			11,975	37,193
Cash and cash equivalents at end of period	673,309	84,464	673,309	84,464
Reportable Legal Entities \| Parent Issuer & Guarantor
Operating activities
Cash provided by operating activities			761,900	964,400
Investing activities
Capital expenditures			(17,800)	(15,000)
Contributions to unconsolidated affiliates			0	0
Other investing activities			0	0
Cash used in investing activities			(17,800)	(15,000)
Financing activities
Dividends paid			(1,079,400)	(983,100)
Distributions to noncontrolling interests				0
Intercompany borrowings (advances), net			(2,874,400)	(1,640,500)
Borrowing (repayment) of short-term borrowings, net				(494,700)
Issuance of long-term debt, net of discounts			4,185,400	1,245,800
Repayment of long-term debt			(250,000)	0
Issuance of common stock			19,300	1,195,100
Acquisition of noncontrolling interests				(195,000)
Other, net			(83,700)	(29,700)
Cash provided by (used in) financing activities			(82,800)	(902,100)
Change in cash and cash equivalents			661,300	47,300
Cash and cash equivalents at beginning of period			12,000	37,200
Cash and cash equivalents at end of period	673,300	84,500	673,300	84,500
Reportable Legal Entities \| Subsidiary Issuer & Guarantor
Operating activities
Cash provided by operating activities			897,300	993,800
Investing activities
Capital expenditures			0	0
Contributions to unconsolidated affiliates			0	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
Intercompany borrowings (advances), net			904,100	930,200
Borrowing (repayment) of short-term borrowings, net				0
Issuance of long-term debt, net of discounts			0	0
Repayment of long-term debt			(799,700)	(925,000)
Issuance of common stock			0	0
Acquisition of noncontrolling interests				0
Other, net			(2,700)	0
Cash provided by (used in) financing activities			(897,300)	(993,800)
Change in cash and cash equivalents			0	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			50,600	48,900
Investing activities
Capital expenditures			0	0
Contributions to unconsolidated affiliates			0	(500)
Other investing activities			72,500	10,800
Cash used in investing activities			72,500	10,300
Financing activities
Dividends paid			(999,000)	(999,000)
Distributions to noncontrolling interests				0
Intercompany borrowings (advances), net			875,900	939,800
Borrowing (repayment) of short-term borrowings, net				0
Issuance of long-term debt, net of discounts			0	0
Repayment of long-term debt			0	0
Issuance of common stock			0	0
Acquisition of noncontrolling interests				0
Other, net			0	0
Cash provided by (used in) financing activities			(123,100)	(59,200)
Change in cash and cash equivalents			0	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 \| Combined Non-Guarantor Subsidiaries
Operating activities
Cash provided by operating activities			1,615,000	1,507,400
Investing activities
Capital expenditures			(2,721,500)	(1,294,700)
Contributions to unconsolidated affiliates			(3,300)	(300)
Other investing activities			22,200	9,900
Cash used in investing activities			(2,702,600)	(1,285,100)
Financing activities
Dividends paid			0	0
Distributions to noncontrolling interests				(3,500)
Intercompany borrowings (advances), net			1,094,400	(229,500)
Borrowing (repayment) of short-term borrowings, net				0
Issuance of long-term debt, net of discounts			0	0
Repayment of long-term debt			(5,700)	(5,700)
Issuance of common stock			0	0
Acquisition of noncontrolling interests				0
Other, net			(1,100)	16,400
Cash provided by (used in) financing activities			1,087,600	(222,300)
Change in cash and cash equivalents			0	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			1,326,800	1,516,500
Investing activities
Capital expenditures			(2,739,300)	(1,309,700)
Contributions to unconsolidated affiliates			(3,300)	(800)
Other investing activities			94,700	20,700
Cash used in investing activities			(2,647,900)	(1,289,800)
Financing activities
Dividends paid			(1,079,400)	(983,100)
Distributions to noncontrolling interests				(3,500)
Intercompany borrowings (advances), net			0	0
Borrowing (repayment) of short-term borrowings, net				(494,700)
Issuance of long-term debt, net of discounts			4,185,400	1,245,800
Repayment of long-term debt			(1,055,400)	(930,700)
Issuance of common stock			19,300	1,195,100
Acquisition of noncontrolling interests				(195,000)
Other, net			(87,500)	(13,300)
Cash provided by (used in) financing activities			1,982,400	(179,400)
Change in cash and cash equivalents			661,300	47,300
Cash and cash equivalents at beginning of period			12,000	37,200
Cash and cash equivalents at end of period	673,300	84,500	673,300	84,500
Consolidating Entries
Operating activities
Cash provided by operating activities			(1,998,000)	(1,998,000)
Investing activities
Capital expenditures			0	0
Contributions to unconsolidated affiliates			0	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				0
Intercompany borrowings (advances), net			0	0
Borrowing (repayment) of short-term borrowings, net				0
Issuance of long-term debt, net of discounts			0	0
Repayment of long-term debt			0	0
Issuance of common stock			0	0
Acquisition of noncontrolling interests				0
Other, net			0	0
Cash provided by (used in) financing activities			1,998,000	1,998,000
Change in cash and cash equivalents			0	0
Cash and cash equivalents at beginning of period			0	0
Cash and cash equivalents at end of period	$ 0	$ 0	$ 0	$ 0