Midstream (EQTNP) 10-Q 3 Nov 20 2020 Q3 Quarterly report Financial data

Cover

Cover - shares	9 Months Ended
	Sep. 30, 2020	Oct. 31, 2020	Dec. 31, 2019
Cover [Abstract]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
Entity File Number	001-38629
Entity Registrant Name	EQUITRANS MIDSTREAM CORPORATION
Entity Incorporation, State or Country Code	PA
Entity Tax Identification Number	83-0516635
Entity Address, Address Line One	2200 Energy Drive
Entity Address, City or Town	Canonsburg
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	15317
City Area Code	724
Local Phone Number	271-7600
Title of 12(b) Security	Common Stock, no par value
Trading Symbol	ETRN
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Emerging Growth Company	false
Small Business Entity	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		432,470,000
Mezzanine equity, preferred shares outstanding (in shares)	30,018,000	30,018,000	0
Entity Central Index Key	0001747009
Amendment Flag	false
Current Fiscal Year End	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3

Statements of Consolidated Comp

Statements of Consolidated Comprehensive Income (Unaudited) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Operating revenues	[1]	$ 350,000	$ 408,434	$ 1,143,703	$ 1,204,383
Operating expenses:
Operating and maintenance	[1]	33,905	43,021	113,990	117,460
Selling, general and administrative	[1]	31,626	24,151	94,186	83,553
Separation and other transaction costs		984	256	23,797	24,606
Depreciation		66,772	59,460	191,271	166,730
Amortization of intangible assets		16,204	14,540	46,990	38,677
Impairment of long-lived assets	[2]	0	305,459	55,581	385,594
Total operating expenses		149,491	446,887	525,815	816,620
Operating income (loss)		200,509	(38,453)	617,888	387,763
Equity income	[3]	60,917	44,448	171,233	112,293
Other income	[4]	21,864	70	39,006	2,637
Loss on early extinguishment of debt	[5]	0	0	24,864	0
Net interest expense	[1]	86,411	65,606	219,960	188,268
Income (loss) before income taxes		196,879	(59,541)	583,303	314,425
Income tax expense		28,440	1,948	81,846	45,868
Net income (loss)		168,439	(61,489)	501,457	268,557
Net income attributable to noncontrolling interests		3,973	4,336	210,765	203,562
Net income (loss) attributable to Equitrans Midstream		164,466	(65,825)	290,692	64,995
Preferred dividends	[6]	14,628	0	44,132	0
Net income (loss) attributable to Equitrans Midstream common shareholders		$ 149,838	$ (65,825)	$ 246,560	$ 64,995
Earnings (loss) per share of common stock attributable to Equitrans Midstream common shareholders - basic (in dollars per share)	[7]	$ 0.35	$ (0.26)	$ 0.78	$ 0.26
Earnings (loss) per share of common stock attributable to Equitrans Midstream common shareholders - diluted (in dollars per share)	[7]	$ 0.35	$ (0.26)	$ 0.78	$ 0.25
Weighted average common shares outstanding - basic (in shares)		432,773,000	254,915,000	314,411,000	254,868,000
Weighted average common shares outstanding - diluted (in shares)		432,821,000	254,915,000	314,411,000	254,887,000
Statement of comprehensive income (loss):
Net income (loss)		$ 168,439	$ (61,489)	$ 501,457	$ 268,557
Other comprehensive income (loss), net of tax:
Pension and other post-retirement benefits liability adjustment, net of tax expense of $10, $7, $30 and $22		30	21	90	(252)
Other comprehensive income (loss)		30	21	90	(252)
Comprehensive income (loss)		168,469	(61,468)	501,547	268,305
Less: Comprehensive income attributable to noncontrolling interests		3,973	4,336	210,765	203,562
Less: Comprehensive income attributable to preferred dividends	[6]	14,628	0	44,132	0
Comprehensive income (loss) attributable to Equitrans Midstream common shareholders		$ 149,868	$ (65,804)	$ 246,650	$ 64,743
Dividends declared per common share (in dollars per share)		$ 0.15	$ 0.45	$ 0.45	$ 1.35
[1]	Includes related party activity with EQT. See Note 7.
[2]	See Note 4 for disclosure regarding impairments of long-lived assets.
[3]	Represents equity income from the MVP Joint Venture. See Note 8.
[4]	See Note 10 for disclosures regarding derivative instruments.
[5]	See Note 9 for disclosure regarding loss on early extinguishment of debt.
[6]	See Notes 2 and 11
[7]	See Note 11 for disclosure regarding the Company's calculation of net income per share of common stock (basic and diluted).

Statements of Consolidated Co_2

Statements of Consolidated Comprehensive Income (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended						9 Months Ended
	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Pension and other post-retirement benefits liability adjustments, tax expense	$ 10	$ 10	$ 10	$ 7	$ 7	$ 8	$ 30	$ 22

Statements of Consolidated Cash

Statements of Consolidated Cash Flows (Unaudited) - USD ($) $ in Thousands		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019
Cash flows from operating activities:
Net income		$ 501,457	$ 268,557
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation		191,271	166,730
Amortization of intangible assets		46,990	38,677
Deferred income taxes		79,415	45,868
Impairments of long-lived assets (Note 4)	[1]	55,581	385,594
Equity income (Note 8)	[2]	(171,233)	(112,293)
Other income		(38,403)	(3,866)
Loss on early extinguishment of debt	[3]	24,864	0
Share-based compensation plans		9,388	1,900
Changes in other assets and liabilities:
Accounts receivable		(11,021)	28,773
Accounts payable		3,151	(72,369)
Accrued interest		(5,592)	(39,103)
Deferred revenue		148,770	0
Other assets and other liabilities		(10,443)	(17,999)
Net cash provided by operating activities		824,195	690,469
Cash flows from investing activities:
Capital expenditures		(377,592)	(769,937)
Capital contributions to the MVP Joint Venture		(144,264)	(512,852)
Bolt-on Acquisition (as defined in Note 3), net of cash acquired		0	(837,231)
Principal payments received on the Preferred Interest		3,726	3,471
Net cash used in investing activities		(518,130)	(2,116,549)
Cash flows from financing activities:
Proceeds from revolving credit facility borrowings		1,965,000	1,969,000
Payments on revolving credit facility borrowings		(2,080,000)	(2,325,500)
Proceeds from the issuance of long-term debt		1,600,000	1,400,000
Debt issuance costs and credit facility origination fees		(26,720)	(2,563)
Payment for retirement of long-term debt		(594,000)	(32,825)
Redemption of EQM Series A Preferred Units (as defined in Note 1)		(617,338)	0
Distributions paid to noncontrolling interest EQM unitholders		(128,770)	(285,834)
Dividends paid to common shareholders		(213,524)	(333,493)
Cash Shares and Cash Amount (as defined in Note 6)		(52,323)	0
Purchase of EQGP Common Units (as defined in Note 2)		0	(238,455)
Proceeds from issuance of EQM Series A Preferred Units, net of offering costs		0	1,158,313
Net cash (used in) provided by financing activities		(211,857)	1,285,664
Net change in cash and cash equivalents		94,208	(140,416)
Cash and cash equivalents at beginning of period		88,322	294,172
Cash, restricted cash and cash equivalents at end of period		182,530	153,756
Cash paid during the period for:
Interest, net of amount capitalized		221,918	223,257
Non-cash activity during the period for:
Contract liability		121,483	0
Series A Preferred Units
Cash flows from financing activities:
Distributions paid to holders of EQM Series A Preferred Units (as defined in Note 1)		(61,931)	(22,979)
Dividends paid to holders of Equitrans Midstream Preferred Shares		(61,931)	(22,979)
Preferred Stock
Cash flows from financing activities:
Distributions paid to holders of EQM Series A Preferred Units (as defined in Note 1)		(2,251)	0
Dividends paid to holders of Equitrans Midstream Preferred Shares		(2,251)	0
Common Stock
Non-cash activity during the period for:
Issuance of Equitrans Midstream shares		2,736,229	0
Convertible Preferred Stock
Non-cash activity during the period for:
Issuance of Equitrans Midstream shares		$ 667,214	$ 0
[1]	See Note 4 for disclosure regarding impairments of long-lived assets.
[2]	Represents equity income from the MVP Joint Venture. See Note 8.
[3]	See Note 9 for disclosure regarding loss on early extinguishment of debt.

Consolidated Balance Sheets (Un

Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands		Sep. 30, 2020	Dec. 31, 2019
Current assets:
Cash and cash equivalents		$ 182,530	$ 88,322
Accounts receivable (net of allowance for credit losses of $3,609 and allowance for doubtful accounts of $285 as of September 30, 2020 and December 31, 2019, respectively)	[1],[2]	263,657	255,344
Other current assets	[2]	86,855	31,546
Total current assets		533,042	375,212
Property, plant and equipment		8,782,420	8,583,124
Less: accumulated depreciation		(943,687)	(859,157)
Net property, plant and equipment		7,838,733	7,723,967
Investment in unconsolidated entity		2,722,081	2,324,108
Goodwill		486,698	486,698
Net intangible assets		732,795	797,439
Deferred income tax asset		0	90,597
Other assets	[2]	317,331	243,688
Total assets		12,630,680	12,041,709
Current liabilities:
Current portion of revolving credit facility borrowings and long-term debt	[3]	302,500	6,000
Accounts payable		101,134	128,114
Capital contributions payable to the MVP Joint Venture		127,626	45,150
Accrued interest		67,863	73,455
Accrued liabilities		73,187	83,238
Total current liabilities		672,310	335,957
Long-term liabilities:
Revolving credit facility borrowings	[4]	485,000	902,500
Long-term debt		6,440,628	5,421,983
Contract liability	[5]	321,775	0
Deferred income tax liability		293,583	0
Regulatory and other long-term liabilities		95,889	99,189
Total liabilities		8,309,185	6,759,629
Mezzanine equity:
Equitrans Midstream Preferred Shares, 30,018 and 0 shares issued and outstanding as of September 30, 2020 and December 31, 2019, respectively.	[6]	681,842	0
Shareholders' equity:
Common stock, no par value, 432,470 and 254,745 shares issued and outstanding as of September 30, 2020 and December 31, 2019, respectively		3,955,934	1,292,804
Retained deficit		(781,363)	(618,062)
Accumulated other comprehensive loss		(1,936)	(2,026)
Total common shareholders' equity		3,172,635	672,716
Noncontrolling interests		467,018	4,609,364
Total shareholders' equity		3,639,653	5,282,080
Total liabilities, mezzanine equity and shareholders' equity		$ 12,630,680	$ 12,041,709
[1]	See Note 1 for a discussion of the adoption of ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments.
[2]	Includes related party activity with EQT. See Note 7
[3]	Includes aggregate borrowings outstanding on the Eureka Credit Facility (as defined in Note 9) as of September 30, 2020. See Note 9 for further detail.
[4]	Includes aggregate borrowings outstanding on the Amended EQM Credit Facility (as defined in Note 9) as of September 30, 2020. As of December 31, 2019, the Company had aggregate borrowings outstanding of approximately $610 million and $293 million on the Amended EQM Credit Facility and the Eureka Credit Facility, respectively. The Company had no borrowings outstanding under the Equitrans Midstream Credit Facility as of December 31, 2019. See Note 9 for further detail.
[5]	See Note 6 for disclosure regarding the Company's contract liabilities.
[6]	See Note 2 for disclosures regarding the Equitrans Midstream Preferred Shares.

Consolidated Balance Sheets (_2

Consolidated Balance Sheets (Unaudited) (Parenthetical) - USD ($)	Sep. 30, 2020	Dec. 31, 2019
Accounts receivable, for doubtful accounts	$ 3,609,000	$ 285,000
Mezzanine equity, preferred shares outstanding (in shares)	30,018,000	0
Mezzanine equity, preferred shares issued (in shares)	30,018,000	0
Common stock, shares issued (in shares)	432,470,000	254,745,000
Common stock, shares outstanding (in shares)	432,470,000	254,745,000
Equitrans Midstream Credit Facility | Line of credit
Long term line of credit		$ 0
EQM Midstream Partners, LP | Revolving Credit Facility | EQM Credit Facility
Borrowings outstanding	$ 485,000,000	610,000,000
Eureka Midstream, LLC | Eureka Credit Facility
Borrowings outstanding		$ 293,000,000
Eureka Midstream, LLC | Eureka Credit Facility | Line of credit
Borrowings outstanding	$ 303,000,000

Statements of Consolidated Shar

Statements of Consolidated Shareholders' Equity and Mezzanine Equity (Unaudited) - USD ($) $ in Thousands		Total	Series A Preferred Units	EQM Merger	Cumulative Effect, Period of Adoption, Adjustment	Common Stock	Common StockEQM Merger	Retained Earnings (Deficit)	Retained Earnings (Deficit)Cumulative Effect, Period of Adoption, Adjustment	Accumulated Other Comprehensive Loss	Noncontrolling Interests	Noncontrolling InterestsSeries A Preferred Units	Noncontrolling InterestsEQM Merger
Beginning balance (in shares) at Dec. 31, 2018						254,271,000
Beginning balance at Dec. 31, 2018		$ 5,259,633				$ 425,370		$ 33,932		$ (1,509)	$ 4,801,840
Increase (Decrease) in Partners' Capital
Net income		199,566						56,299			143,267
Pension and other post-retirement benefits liability adjustment, net of tax expense		21						316		(295)
Dividends		(104,251)						(104,251)
Share-based compensation plans (in shares)						413,000
Share-based compensation plans		1,108				$ 853					255
Distributions paid to noncontrolling interest unitholders		(94,030)									(94,030)
Net changes in ownership of consolidated entities		(346,543)				991,098					(1,337,641)
Share Purchase Agreements (as defined in Note 6)		(238,455)				$ (38,648)					(199,807)
Ending balance (in shares) at Mar. 31, 2019						254,684,000
Ending balance at Mar. 31, 2019		$ 4,677,049				$ 1,378,673		(13,704)		(1,804)	3,313,884
Increase (Decrease) in Mezzanine Equity
Dividends (in dollars per share)		$ 0.41
Pension and other post-retirement benefits liability adjustments, tax expense		$ 8
Beginning balance (in shares) at Dec. 31, 2018						254,271,000
Beginning balance at Dec. 31, 2018		5,259,633				$ 425,370		33,932		(1,509)	4,801,840
Increase (Decrease) in Partners' Capital
Net income		268,557
Ending balance (in shares) at Sep. 30, 2019						254,744,000
Ending balance at Sep. 30, 2019		5,941,250				$ 1,381,092		(234,250)		(1,761)	4,796,169
Increase (Decrease) in Mezzanine Equity
Pension and other post-retirement benefits liability adjustments, tax expense		22
Beginning balance (in shares) at Mar. 31, 2019						254,684,000
Beginning balance at Mar. 31, 2019		4,677,049				$ 1,378,673		(13,704)		(1,804)	3,313,884
Increase (Decrease) in Partners' Capital
Net income		130,480						74,521			55,959
Pension and other post-retirement benefits liability adjustment, net of tax expense		22								22
Dividends		(114,608)						(114,608)
Share-based compensation plans (in shares)						7,000
Share-based compensation plans		1,510				$ 1,510
Distributions paid to noncontrolling interest unitholders		(95,278)									(95,278)
Issuance of EQM Series A Preferred Units, net of offering costs		1,158,313									1,158,313
Bolt-on Acquisition		486,062									486,062
Net changes in ownership of consolidated entities		1,627				$ 1,627
Ending balance (in shares) at Jun. 30, 2019						254,691,000
Ending balance at Jun. 30, 2019		$ 6,245,177				$ 1,381,810		(53,791)		(1,782)	4,918,940
Increase (Decrease) in Mezzanine Equity
Dividends (in dollars per share)		$ 0.45
Pension and other post-retirement benefits liability adjustments, tax expense		$ 7
Net income		(61,489)						(65,825)			4,336
Pension and other post-retirement benefits liability adjustment, net of tax expense		21								21
Dividends		(114,634)						(114,634)
Share-based compensation plans (in shares)						53,000
Share-based compensation plans		(718)				$ (718)
Distributions paid to noncontrolling interest unitholders		(96,526)									(96,526)
Distributions paid to EQM Series A Preferred unitholders			$ (22,979)									$ (22,979)
Bolt-on Acquisition measurement period adjustments (Note 3)		(7,602)									(7,602)
Ending balance (in shares) at Sep. 30, 2019						254,744,000
Ending balance at Sep. 30, 2019		$ 5,941,250				$ 1,381,092		(234,250)		(1,761)	4,796,169
Increase (Decrease) in Mezzanine Equity
Dividends (in dollars per share)		$ 0.45
Pension and other post-retirement benefits liability adjustments, tax expense		$ 7
Beginning balance (in shares) at Dec. 31, 2019		254,745,000				254,745,000
Beginning balance at Dec. 31, 2019		$ 5,282,080			$ (3,718)	$ 1,292,804		(618,062)	$ (3,718)	(2,026)	4,609,364
Increase (Decrease) in Partners' Capital
Net income		189,560						69,732			119,828
Pension and other post-retirement benefits liability adjustment, net of tax expense		30								30
Dividends (shares)						(178,000)
Dividends		(115,400)						(115,400)
Share-based compensation plans (in shares)						85,000
Share-based compensation plans		4,785				$ 4,500					285
Distributions paid to noncontrolling interest unitholders		(96,526)									(96,526)
Distributions paid to EQM Series A Preferred unitholders		(25,501)									(25,501)
Share Purchase Agreements (as defined in Note 6) (in shares)						(25,300,000)
Share Purchase Agreements (as defined in Note 6)		(190,992)						(190,992)
Ending balance (in shares) at Mar. 31, 2020						229,352,000
Ending balance at Mar. 31, 2020		5,044,318				$ 1,297,304		(858,440)		(1,996)	4,607,450
Mezzanine Equity, beginning balance at Dec. 31, 2019	[1]	0
Mezzanine Equity, ending balance at Mar. 31, 2020		$ 0
Increase (Decrease) in Mezzanine Equity
Dividends (in dollars per share)		$ 0.45
Pension and other post-retirement benefits liability adjustments, tax expense		$ 10
Beginning balance (in shares) at Dec. 31, 2019		254,745,000				254,745,000
Beginning balance at Dec. 31, 2019		$ 5,282,080			$ (3,718)	$ 1,292,804		(618,062)	$ (3,718)	(2,026)	4,609,364
Increase (Decrease) in Partners' Capital
Net income		$ 501,457
Ending balance (in shares) at Sep. 30, 2020		432,470,000				432,470,000
Ending balance at Sep. 30, 2020		$ 3,639,653				$ 3,955,934		(781,363)		(1,936)	467,018
Mezzanine Equity, beginning balance at Dec. 31, 2019	[1]	0
Mezzanine Equity, ending balance at Sep. 30, 2020	[1]	681,842
Increase (Decrease) in Mezzanine Equity
Pension and other post-retirement benefits liability adjustments, tax expense		30
Beginning balance (in shares) at Mar. 31, 2020						229,352,000
Beginning balance at Mar. 31, 2020		5,044,318				$ 1,297,304		(858,440)		(1,996)	4,607,450
Increase (Decrease) in Partners' Capital
Net income, excluding amount attributable mezzanine equity		141,207						54,243			86,964
Pension and other post-retirement benefits liability adjustment, net of tax expense		30								30
Dividends		(34,634)						(34,634)
Share-based compensation plans (in shares)						(20,000)
Share-based compensation plans		1,856				$ 1,856
Distributions paid to noncontrolling interest unitholders		(32,244)									(32,244)
Net changes in ownership of consolidated entities						82,700					579,200
Distributions paid to EQM Series A Preferred unitholders		(25,501)		$ (10,929)							(25,501)		$ (10,929)
Redemption of EQM Series A Preferred Units		(617,338)						(27,253)			(590,085)
Restructuring Agreement (as defined in Note 1)		(661,874)				$ (82,717)					(579,157)
EQM Merger (as defined in Note 1) (in shares)						203,137,000
EQM Merger (as defined in Note 1)		(257,224)				$ 2,736,229					(2,993,453)
Ending balance (in shares) at Jun. 30, 2020						432,469,000
Ending balance at Jun. 30, 2020		3,547,667				$ 3,952,672		(866,084)		(1,966)	463,045
Mezzanine Equity, beginning balance at Mar. 31, 2020		0
Increase (Decrease) in Mezzanine Equity
Mezzanine Equity, Net income		2,251
Mezzanine Equity, Restructuring Agreement (as defined in Note 1)		667,214
Mezzanine Equity, ending balance at Jun. 30, 2020		$ 669,465
Increase (Decrease) in Mezzanine Equity
Dividends (in dollars per share)		$ 0.15
Pension and other post-retirement benefits liability adjustments, tax expense		$ 10
Net income		168,439
Net income, excluding amount attributable mezzanine equity		153,811						149,838			3,973
Pension and other post-retirement benefits liability adjustment, net of tax expense		30								30
Dividends		(65,117)						(65,117)
Share-based compensation plans (in shares)						1,000
Share-based compensation plans		$ 3,262				$ 3,262
Net changes in ownership of consolidated entities							$ 2,700,000						$ 3,000,000
Ending balance (in shares) at Sep. 30, 2020		432,470,000				432,470,000
Ending balance at Sep. 30, 2020		$ 3,639,653				$ 3,955,934		$ (781,363)		$ (1,936)	$ 467,018
Increase (Decrease) in Mezzanine Equity
Mezzanine Equity, Net income		14,628
Mezzanine Equity, Dividends paid to holders of Equitrans Midstream Preferred Shares ($0.075 per share)		(2,251)
Mezzanine Equity, ending balance at Sep. 30, 2020	[1]	$ 681,842
Increase (Decrease) in Mezzanine Equity
Dividends (in dollars per share)		$ 0.15
Pension and other post-retirement benefits liability adjustments, tax expense		$ 10
[1]	See Note 2 for disclosures regarding the Equitrans Midstream Preferred Shares.

Statements of Consolidated Sh_2

Statements of Consolidated Shareholders' Equity and Mezzanine Equity (Unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
Pension and other post-retirement benefits liability adjustments, tax expense	$ 10	$ 10	$ 7	$ 7	$ 8
Dividends (in dollars per share)	$ 0.15	$ 0.45	$ 0.45	$ 0.45	$ 0.41
EQM Midstream Partners, LP
Cash distributions declared (in dollars per unit)	0.3875	1.16	1.160	$ 1.145	$ 1.13
Series A Preferred Units
Cash distributions declared (in dollars per unit)			$ 0.9339
Series A Preferred Units | EQM Midstream Partners, LP
Cash distributions declared (in dollars per unit)	$ 1.0364	$ 1.0364

Financial Statements

Financial Statements	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Financial Statements	Financial Statements Organization. On November 12, 2018, Equitrans Midstream Corporation (together with its consolidated subsidiaries as applicable, the Company or Equitrans Midstream), EQT and, for certain limited purposes, EQT Production Company, a wholly owned subsidiary of EQT, entered into a Separation and Distribution Agreement, pursuant to which, among other things, EQT effected the separation of EQT's midstream business, which was composed of the separately-operated natural gas gathering, transmission and storage and water services operations of EQT, from EQT's upstream business, which was composed of the natural gas, oil and natural gas liquids development, production and sales and commercial operations of EQT (the Separation), including the transfer of certain assets and liabilities to Equitrans Midstream, and distributed 80.1% of the then-outstanding shares of common stock, no par value, of Equitrans Midstream (Equitrans Midstream common stock) to EQT shareholders of record as of the close of business on November 1, 2018 (the Distribution). The Distribution was effective at 11:59 p.m., Eastern Time, on November 12, 2018. As part of the Separation, EQT retained the remaining 19.9% of the outstanding shares in Equitrans Midstream. EQM Merger. On June 17, 2020, pursuant to that certain Agreement and Plan of Merger, dated as of February 26, 2020 (the EQM Merger Agreement), by and among the Company, EQM LP Corporation, a wholly owned subsidiary of the Company (EQM LP), LS Merger Sub, LLC, a wholly owned subsidiary of EQM LP (Merger Sub), EQM and EQGP Services, LLC, the general partner of EQM (the EQM General Partner), Merger Sub merged with and into EQM (the EQM Merger), with EQM continuing and surviving as an indirect, wholly owned subsidiary of the Company. Upon consummation of the EQM Merger, the Company acquired all of the outstanding common units representing limited partner interests in EQM (EQM Common Units) that the Company and its subsidiaries did not already own. Following the closing of the EQM Merger, EQM was no longer a publicly traded entity. See Note 2 for further information on the EQM Merger. Preferred Restructuring Agreement. On February 26, 2020, Equitrans Midstream and EQM entered into a Preferred Restructuring Agreement (the Restructuring Agreement) with all of the holders of the Series A Perpetual Convertible Preferred Units representing limited partner interests in EQM (such units, EQM Series A Preferred Units and, such investors, collectively, the Investors), pursuant to which, at the effective time of the EQM Merger (the Effective Time): (i) EQM redeemed $600 million aggregate principal amount of the Investors' EQM Series A Preferred Units issued and outstanding immediately prior to the Restructuring Closing (defined below), which occurred substantially concurrent with the closing of the EQM Merger, for cash at 101% of the EQM Series A Preferred Unit purchase price of $48.77 per such unit (the EQM Series A Preferred Unit Purchase Price) plus any accrued and unpaid distribution amounts and partial period distribution amounts, and (ii) immediately following such redemption, each remaining issued and outstanding EQM Series A Preferred Unit was exchanged for 2.44 shares of a newly authorized and created series of preferred stock, without par value, of Equitrans Midstream, convertible into Equitrans Midstream common stock (the Equitrans Midstream Preferred Shares) on a one for one basis, in each case, in connection with the occurrence of the “Series A Change of Control” (as defined in the Fourth Amended and Restated Agreement of Limited Partnership of EQM (as amended, the Former EQM Partnership Agreement)) that occurred upon the closing of the EQM Merger (collectively, the Restructuring and, the closing of the Restructuring, the Restructuring Closing). See Note 2 for further information on the Restructuring Agreement. Basis of Presentation. References in these financial statements to Equitrans Midstream or the Company refer collectively to Equitrans Midstream Corporation and, as applicable, its consolidated subsidiaries for all periods presented, unless otherwise indicated. The accompanying unaudited consolidated financial statements have been prepared in accordance with GAAP for interim financial information and with the requirements of Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, these unaudited consolidated financial statements include all adjustments (consisting of only normal, recurring adjustments, unless otherwise disclosed in this Quarterly Report on Form 10-Q) necessary for a fair presentation of the financial position of the Company as of September 30, 2020 and December 31, 2019, the results of its operations and equity for the three and nine months ended September 30, 2020 and 2019 and its cash flows for the nine months ended September 30, 2020 and 2019. The consolidated balance sheet at December 31, 2019 has been derived from the audited financial statements at that date but does not include all of the information and notes required by GAAP for complete financial statements. This Quarterly Report on Form 10-Q should be read in conjunction with the Company's Annual Report on Form 10-K for the year ended December 31, 2019, which includes all disclosures required by GAAP. Due to, among other things, the seasonal nature of the Company's utility customer contracts and temporary volume curtailments by certain of the Company's customers, including EQT, as well as producers’ well completion activities and varying needs for fresh and produced water (which are partially driven by horizontal lateral lengths and the number of completion stages per well), the interim statements for the three and nine months ended September 30, 2020 are not necessarily indicative of the results that may be expected for the year ending December 31, 2020. For further information, refer to the Company's annual consolidated financial statements and related notes in the Company's Annual Report on Form 10-K for the year ended December 31, 2019, as well as "Management's Discussion and Analysis of Financial Condition and Results of Operations" contained herein. Recently Issued Accounting Standards In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The standard amended guidance on reporting credit losses for assets held at amortized cost basis and available for sale debt securities. For assets held at amortized cost basis, this standard eliminated the probable initial recognition threshold in then current GAAP, and, in its place, requires an entity to recognize its current estimate of all expected credit losses. The amendments affected loans, debt securities, trade receivables, contract assets, net investments in leases, off balance sheet credit exposures, reinsurance receivables, and any other financial assets not excluded from the scope of the standard that have the contractual right to receive cash. In May 2019, the FASB issued ASU 2019-05, Financial Instruments – Credit Losses (Topic 326). The update provides entities with targeted transition relief that is intended to increase comparability of financial statement information for some entities that otherwise would have measured similar financial instruments using different measurement methodologies. In November 2019, the FASB issued ASU 2019-11, Codification Improvements to Topic 326, Financial Instruments – Credit Losses. The update clarifies and addresses stakeholders' specific issues in ASU 2016-13. The Company adopted the standard on January 1, 2020, using the modified retrospective method for all financial assets recorded at amortized cost. Results for reporting periods beginning after January 1, 2020 are presented under Topic 326 while prior period amounts continue to be reported in accordance with previously applicable GAAP. The Company's current expected credit loss (CECL) methodology considers risks of collection based on a customer’s current credit status. The standard requires an entity to assess whether financial assets share similar risk characteristics and, if so, group such assets in a pool. Customer balances are aggregated for evaluation based on their credit risk rating, which takes into account changes in economic factors that impact a customer’s ability to meet its financial obligations. The Company's CECL methodology assigns a reserve, even if remote, to each customer based on credit risk. The table below summarizes the changes in the allowance for credit losses by outstanding receivable for the nine months ended September 30, 2020: Accounts Receivable Contract Asset (a) Other Assets (b) Total Balance at December 31, 2019 $ (285) $ — $ — $ (285) Adoption of Topic 326 (2,708) — (1,010) (3,718) Provision for (recovery of) expected credit losses (616) (222) 26 (812) Balance at September 30, 2020 $ (3,609) $ (222) $ (984) $ (4,815) (a) Included in other current assets in the consolidated balance sheets. (b) Includes the Company's Preferred Interest in EES and other long-term receivables. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement, Changes to the Disclosure Requirements for Fair Value Measurement , which makes a number of changes to the hierarchy associated with Level 1, 2 and 3 fair value measurements and the related disclosure requirements. This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The Company adopted this standard on January 1, 2020. The adoption of this standard did not have an impact on the Company's financial statements. In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes , which enhances and simplifies various aspects of the income tax accounting guidance including the elimination of certain exceptions related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The guidance also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. The guidance will be effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020, with early adoption permitted. The Company early-adopted the standard in the first quarter of 2020 with no significant effect on its financial statements or related disclosures. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848) , which provides practical expedients for contract modifications and certain hedging relationships associated with the transition from reference rates that are expected to be discontinued. This guidance is applicable for the Amended EQM Credit Facility, the Amended 2019 EQM Term Loan Agreement (as defined in Note 9) and the Eureka Credit Facility, as well as for each dividend following March 31, 2024 for the Equitrans Midstream Preferred Shares, which each use the London Inter-Bank Offered Rate (LIBOR) as a reference rate. The ASU is effective immediately but is only available through December 31, 2022. The Company is currently evaluating the potential impact of this standard on its financial statements. In August 2020, the FASB issued ASU 2020-06, Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity , which simplifies the accounting for convertible debt and convertible preferred stock by removing the requirements to separately present certain conversion features in equity. In addition, the amendments in the ASU 2020-06 also simplify the guidance in ASC Subtopic 815-40, Derivatives and Hedging: Contracts in Entity’s Own Equity , by removing certain criteria that must be satisfied in order to classify a contract as equity. Finally, the amendments revise the guidance on calculating earnings per share, requiring use of the if-converted method for all convertible instruments and rescinding an entity’s ability to rebut the presumption of share settlement for instruments that may be settled in cash or other assets. The amendments will be effective for fiscal years beginning after December 15, 2021. Early adoption is permitted for fiscal years beginning after December 15, 2020. Adoption of the guidance must commence at the beginning of the annual fiscal year. The Company is currently evaluating the potential impact of this standard on its financial statements.

Investments in Consolidated, No

Investments in Consolidated, Non-Wholly-Owed Entities	9 Months Ended
	Sep. 30, 2020
Equity [Abstract]
Investments in Consolidated, Non-Wholly-Owed Entities	Investments in Consolidated, Non-Wholly Owned Entities Investment in EQM EQM IDR Transaction . On February 22, 2019, the Company completed a simplification transaction pursuant to that certain Agreement and Plan of Merger, dated as of February 13, 2019, by and among the Company and certain related parties, pursuant to which, among other things, (i) Equitrans Merger Sub, LP merged with and into EQGP (the IDR Merger) with EQGP continuing as the surviving limited partnership and a wholly owned subsidiary of EQM, and (ii) each of (a) the IDRs in EQM, (b) the economic portion of the general partner interest in EQM and (c) the issued and outstanding common units representing limited partner interests in EQGP (EQGP Common Units) were canceled, and, as consideration for such cancellation, certain affiliates of the Company received on a pro rata basis 80,000,000 newly-issued EQM Common Units and 7,000,000 newly-issued Class B units representing limited partner interests in EQM (Class B units), and the EQM General Partner retained the non-economic general partner interest in EQM (such transactions, collectively, the EQM IDR Transaction). Additionally, as part of the EQM IDR Transaction, 21,811,643 EQM Common Units held by EQGP were canceled and 21,811,643 EQM Common Units were issued pro rata to certain subsidiaries of the Company. As a result of the EQM IDR Transaction, the EQM General Partner replaced EQM Midstream Services, LLC as the general partner of EQM. After giving effect to the EQM IDR Transaction, including the issuance of Class B units, Equitrans Gathering Holdings, LLC (Equitrans Gathering Holdings), EQM GP Corporation (EQM GP Corp) and Equitrans Midstream Holdings, LLC (EMH), each a wholly owned subsidiary of Equitrans Midstream, held 89,505,616, 89,536 and 27,650,303 EQM Common Units, respectively, for a total of 117,245,455 EQM Common Units. Additionally, Equitrans Gathering Holdings, EQM GP Corp and EMH held 6,153,907, 6,155 and 839,938 Class B units, respectively, for a total of 7,000,000 Class B units. During the first quarter of 2019, as a result of the EQM IDR Transaction, the Company recorded, in the aggregate, a $991.1 million increase of common stock, no par value, a decrease in noncontrolling interest of $1.3 billion and a decrease in deferred tax asset of $346.5 million. EQM Merger. As discussed in Note 1, on June 17, 2020, the Company, EQM, EQM LP, Merger Sub and the EQM General Partner completed the EQM Merger, pursuant to which Merger Sub merged with and into EQM, with EQM continuing and surviving as an indirect, wholly owned subsidiary of the Company. As a result of the EQM Merger, EQM is no longer a publicly traded entity. At the Effective Time, subject to applicable tax withholding, (i) each outstanding EQM Common Unit, other than EQM Common Units owned by the Company and its subsidiaries, was converted into the right to receive 2.44 shares of Equitrans Midstream common stock (the Merger Consideration); (ii) (x) $600.0 million aggregate principal amount of the EQM Series A Preferred Units issued and outstanding immediately prior to the Effective Time were redeemed by EQM for cash at 101% of the EQM Series A Preferred Unit Purchase Price plus any accrued and unpaid distribution amounts and partial period distribution amounts, and (y) immediately following such redemption, each remaining issued and outstanding EQM Series A Preferred Unit was exchanged for 2.44 Equitrans Midstream Preferred Shares; and (iii) each outstanding phantom unit relating to an EQM Common Unit issued pursuant to the Amended and Restated EQGP Services, LLC 2012 Long-Term Incentive Plan, dated as of February 22, 2019 (the EQM LTIP), and any other award issued pursuant to the EQM LTIP, whether vested or unvested, was converted into the right to receive, with respect to each EQM Common Unit subject thereto, the Merger Consideration (plus any accrued but unpaid amounts in relation to distribution equivalent rights). The limited partner interests in EQM owned by the Company and its subsidiaries (including the Class B units) remained outstanding as limited partner interests in the surviving entity. The EQM General Partner continued to own the non-economic general partner interest in the surviving entity. No fractional shares of Equitrans Midstream common stock were issued in the EQM Merger; instead, all fractions of Equitrans Midstream common stock to which an EQM common unitholder otherwise would have been entitled were aggregated and the resulting fraction was rounded up to the nearest whole share of Equitrans Midstream common stock. In connection with the EQM Merger at the Effective Time, the Company's omnibus and secondment agreements with EQM and certain other subsidiaries of the Company terminated, subject to the survival of certain license rights and indemnification obligations. Because the Company controlled EQM both before and after the EQM Merger, the increase in the Company’s ownership interest in EQM resulting from the EQM Merger was accounted for as an equity transaction and reflected as a reduction of the noncontrolling interest associated with public ownership of EQM Common Units, offset by an increase in common stock, no par value. No gain or loss was recognized in the Company’s statement of consolidated comprehensive income as a result of the EQM Merger. In addition, the tax effects of the EQM Merger are reported as adjustments to deferred income taxes and Equitrans Midstream common stock, consistent with ASC 740, Income Taxes . Immediately prior to the completion of the EQM Merger, the public limited partners collectively owned a 40.1% interest in EQM, excluding the impact of the EQM Series A Preferred Units. The publicly-owned EQM Common Units, prior to completion of the EQM Merger, were reflected within noncontrolling interest in the Company's consolidated balance sheets as of March 31, 2020. The portion of EQM earnings attributable to publicly held EQM Common Units prior to completion of the EQM Merger was reflected in net income attributable to noncontrolling interests in the Company's statements of consolidated comprehensive income. During the second quarter of 2020, as a result of the EQM Merger, the Company recorded, in the aggregate, a $2.7 billion increase of common stock, no par value, a decrease in noncontrolling interest of $3.0 billion and an increase in deferred tax liability of $257.2 million. Additionally, for the period from January 1, 2020 to June 17, 2020, the Company determined that EQM was a variable interest entity. Through the Company's ownership and control of the general partner of EQM during that period, the Company had the power to direct the activities that most significantly affected EQM's economic performance. As a result of the EQM Merger, EQM is no longer a variable interest entity. The Company recorded $1.0 million and $23.8 million in expenses related to the EQM Merger and the EQT Global GGA (defined in Note 4) during the three and nine months ended September 30, 2020, respectively. The expenses consisted of advisor, legal and accounting fees related to the transactions and are included in separation and other transaction costs in the statements of consolidated comprehensive income. Preferred Restructuring Agreement. As discussed in Note 1, on June 17, 2020, concurrently with the closing of the EQM Merger: (i) EQM redeemed $600 million aggregate principal amount of the EQM Series A Preferred Units issued and outstanding immediately prior to the Effective Time for cash at 101% of the EQM Series A Preferred Unit Purchase Price plus any accrued and unpaid distribution amounts and partial period distribution amounts, and (ii) immediately following such redemption, each remaining issued and outstanding EQM Series A Preferred Unit was exchanged for 2.44 Equitrans Midstream Preferred Shares, in each case, in connection with the occurrence of the “Series A Change of Control” (as defined in the Former EQM Partnership Agreement) that occurred upon the closing of the EQM Merger. The Equitrans Midstream Preferred Shares issued were not registered under the Securities Act of 1933, as amended (the Securities Act), in reliance upon the exemption provided in Section 4(a)(2) of the Securities Act and/or Regulation D promulgated thereunder. On June 17, 2020, the Company paid cash of $617.3 million to redeem $600 million aggregate principal amount of the Investors’ EQM Series A Preferred Units and pay partial period distributions on such EQM Series A Preferred Units. At the time of the redemption, the carrying value of the EQM Series A Preferred Units was $590.1 million, resulting in a premium over the carrying value of $27.3 million. The premium represented a return similar to distributions to the holders of the EQM Series A Preferred Units and, as such, reduced net income attributable to Equitrans Midstream common shareholders, and was recorded in retained earnings (deficit) in the statements of consolidated shareholders' equity and mezzanine equity. Pursuant to the Restructuring Agreement, in connection with the Restructuring Closing, the Company filed a statement with respect to shares, attaching a Certificate of Designations (the Certificate of Designations), with the Pennsylvania Department of State on June 17, 2020 to, among other things, authorize and establish the designations, rights and preferences of the Equitrans Midstream Preferred Shares. On August 13, 2020, pursuant to the terms of the Certificate of Designations, the Company paid $10.9 million in the aggregate to holders of Equitrans Midstream Preferred Shares related to forgone partial period distributions on the EQM Series A Preferred Units that were converted into Equitrans Midstream Preferred Shares in connection with the EQM Merger. The Equitrans Midstream Preferred Shares were a new class of security as of June 2020. They rank pari passu with any other outstanding class or series of preferred stock of the Company and senior to Equitrans Midstream common stock with respect to dividend rights and rights upon liquidation. The Equitrans Midstream Preferred Shares vote on an as-converted basis with Equitrans Midstream common stock and have certain other class voting rights with respect to any amendment to the Certificate of Designations or the Company’s Amended and Restated Articles of Incorporation that would be adverse (other than in a de minimis manner) to any of the rights, preferences or privileges of the Equitrans Midstream Preferred Shares. The holders of the Equitrans Midstream Preferred Shares receive cumulative quarterly dividends at a rate per annum of 9.75% for each quarter ending on or before March 31, 2024, and thereafter quarterly dividends at a rate per annum equal to the sum of (i) three-month LIBOR as of the LIBOR Determination Date (as defined in the Certificate of Designations) in respect of the applicable quarter and (ii) 8.15%; provided that such rate per annum in respect of periods after March 31, 2024 will not be less than 10.50%. The Company is not permitted to pay any dividends on any junior securities, including on Equitrans Midstream common stock, prior to paying the quarterly dividends payable to the Equitrans Midstream Preferred Shares, including any previously accrued and unpaid dividends. Each holder of the Equitrans Midstream Preferred Shares may elect to convert all or any portion of the Equitrans Midstream Preferred Shares owned by it into Equitrans Midstream common stock initially on a one-for-one basis, subject to certain anti-dilution adjustments and an adjustment for any dividends that have accrued but not been paid when due and partial period dividends (referred to as the “conversion rate”), at any time (but not more often than once per fiscal quarter) after April 10, 2021 (or immediately prior to a liquidation, dissolution or winding up of the Company), provided that any conversion involves an aggregate number of Equitrans Midstream Preferred Shares of at least $20.0 million (calculated based on the closing price of Equitrans Midstream common stock on the trading day preceding notice of the conversion) or such lesser amount if such conversion relates to all of a holder’s remaining Equitrans Midstream Preferred Shares or if such conversion is approved by the Company's Board of Directors. So long as the holders of the Equitrans Midstream Preferred Shares have not elected to convert all of their Equitrans Midstream Preferred Shares into Equitrans Midstream common stock, the Company may elect to convert all of the Equitrans Midstream Preferred Shares into Equitrans Midstream common stock, at the then-applicable conversion rate, at any time after April 10, 2021 if (i) the shares of Equitrans Midstream common stock are listed for, or admitted to, trading on a national securities exchange, (ii) the closing price per share of Equitrans Midstream common stock on the national securities exchange on which the shares of Equitrans Midstream common stock are listed for, or admitted to, trading exceeds $27.99 for the 20 consecutive trading days immediately preceding notice of the conversion, (iii) the average daily trading volume of the Equitrans Midstream common stock on the national securities exchange on which the shares of Equitrans Midstream common stock are listed for, or admitted to, trading exceeds 1,000,000 shares (subject to certain adjustments) of Equitrans Midstream common stock for the 20 consecutive trading days immediately preceding notice of the conversion, (iv) the Company has an effective registration statement on file with the SEC covering resales of the shares of Equitrans Midstream common stock to be received by such holders upon any such conversion and (v) the Company has paid all prior accumulated and unpaid dividends in cash in full to the holders. Upon certain events involving a Change of Control (as defined in the Certificate of Designations) in which more than 90% of the consideration payable to the Company, or to the holders of Equitrans Midstream common stock, is payable in cash, the Equitrans Midstream Preferred Shares will automatically convert into Equitrans Midstream common stock at a conversion ratio equal to the greater of (i) the quotient of (a) the sum of (x) $19.99 (such price, the Equitrans Midstream Preferred Share Issue Price) plus (y) any accrued and unpaid dividends as of such date, including any partial period dividends, with respect to the Equitrans Midstream Preferred Shares, divided by (b) the Equitrans Midstream Preferred Share Issue Price and (ii) the quotient of (a) the sum of (x)(1) the Equitrans Midstream Preferred Share Issue Price multiplied by (2) 110% plus (y) any accrued and unpaid dividends on such date, including any partial period dividends with respect to the Equitrans Midstream Preferred Shares, divided by (b) the volume weighted average price of the shares of Equitrans Midstream common stock for the 30-day period ending immediately prior to the execution of definitive documentation relating to the Change of Control. In connection with other Change of Control events that do not satisfy the 90% cash consideration threshold described above, in addition to certain other conditions, each holder of Equitrans Midstream Preferred Shares may elect to (i) convert all, but not less than all, of its Equitrans Midstream Preferred Shares into Equitrans Midstream common stock at the then-applicable conversion rate, (ii) if the Company is not the surviving entity (or if the Company is the surviving entity, but Equitrans Midstream common stock will cease to be listed), require the Company to use commercially reasonable efforts to cause the surviving entity in any such transaction to deliver, in exchange for such holder's Equitrans Midstream Preferred Shares, a substantially equivalent security that has rights, preferences and privileges substantially equivalent to the Equitrans Midstream Preferred Shares (or if the Company is unable to cause such substantially equivalent securities to be issued, to exercise the option described in clause (i) or (iv) hereof or elect to convert such Equitrans Midstream Preferred Shares at a conversion ratio reflecting a multiple of invested capital), (iii) if the Company is the surviving entity, continue to hold the Equitrans Midstream Preferred Shares or (iv) require the Company to redeem the Equitrans Midstream Preferred Shares at a price per share equal to 101% of the Equitrans Midstream Preferred Share Issue Price, plus accrued and unpaid dividends, including any partial period dividends, on the applicable Equitrans Midstream Preferred Shares as of such date, which redemption price may be payable in cash, Equitrans Midstream common stock or a combination thereof at the election of the Company's Board of Directors (and, if payable in Equitrans Midstream common stock, such Equitrans Midstream common stock will be issued at 95% of the volume-weighted average price of Equitrans Midstream common stock for the 20-day period ending on the fifth trading day immediately preceding the consummation of the Change of Control). Any holder of Equitrans Midstream Preferred Shares that requires the Company to redeem its Equitrans Midstream Preferred Shares pursuant to clause (iv) above will have the right to withdraw such election with respect to all, but not less than all, of its Equitrans Midstream Preferred Shares at any time prior to the fifth trading day immediately preceding the consummation of the Change of Control and instead elect to be treated in accordance with any of clauses (i), (ii) or (iii) above. At any time on or after January 1, 2024, the Company will have the right, subject to applicable law, to redeem the Equitrans Midstream Preferred Shares, in whole or in part, by paying cash for each Equitrans Midstream Preferred Share to be redeemed in an amount equal to the greater of (a) the sum of (i)(1) the Equitrans Midstream Preferred Share Issue Price multiplied by (2) 110%, plus (ii) any accrued and unpaid dividends, including partial period dividends, with respect to the Equitrans Midstream Preferred Shares as of such date and (b) the amount the holder of such Equitrans Midstream Preferred Share would receive if such holder had converted such Equitrans Midstream Preferred Share into shares of Equitrans Midstream common stock at the then-applicable conversion ratio and the Company liquidated immediately thereafter. Pursuant to the terms of the Restructuring Agreement, in connection with the Restructuring Closing, the Company entered into a registration rights agreement with the Investors (the Registration Rights Agreement) pursuant to which, among other things, the Company gave the Investors certain rights to require the Company to file and maintain one or more registration statements with respect to the resale of the Equitrans Midstream Preferred Shares and the shares of Equitrans Midstream common stock that are issuable upon conversion of the Equitrans Midstream Preferred Shares, and certain Investors have the right to require the Company to initiate underwritten offerings for the Equitrans Midstream Preferred Shares and the shares of Equitrans Midstream common stock that are issuable upon conversion of the Equitrans Midstream Preferred Shares. During the second quarter of 2020, as a result of the Restructuring Closing, the Company recorded an increase in mezzanine equity of $667.2 million, a decrease in noncontrolling interest of $579.2 million and a decrease in common stock, no par value, of $82.7 million, net of deferred taxes of $5.3 million. The Equitrans Midstream Preferred Shares are considered redeemable securities under GAAP due to the possibility of redemption outside the Company’s control. They are therefore presented as temporary equity in the mezzanine equity section of the Company’s consolidated balance sheets and are not considered to be a component of shareholders’ equity on the consolidated balance sheets. The Equitrans Midstream Preferred Shares were recorded at fair value as of the date of issuance, and income allocations increase the carrying value and declared dividends decrease the carrying value of the Equitrans Midstream Preferred Shares. As the Equitrans Midstream Preferred Shares are not currently redeemable and not probable of becoming redeemable, adjustment to the initial carrying amount is not necessary and would only be required if it becomes probable that the Equitrans Midstream Preferred Shares would become redeemable.

Mergers and Acquisitions

Mergers and Acquisitions	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Mergers and Acquisitions	Mergers and Acquisitions EQM Merger. See Note 2. Bolt-on Acquisition. On March 13, 2019, the Company (through EQM) entered into a Purchase and Sale Agreement with North Haven Infrastructure Partners II Buffalo Holdings, LLC (NHIP), an affiliate of Morgan Stanley Infrastructure Partners, pursuant to which the Company acquired from NHIP a 60% Class A interest in Eureka Midstream Holdings, LLC (Eureka Midstream) and a 100% interest in Hornet Midstream Holdings, LLC (Hornet Midstream) (collectively, the Bolt-on Acquisition) for total consideration of approximately $1.04 billion, composed of approximately $852 million in cash, net of purchase price adjustments, and approximately $192 million in assumed pro-rata debt. At the time of the acquisition, Eureka Midstream owned a 190-mile gathering header pipeline system in Ohio and West Virginia that services both dry Utica and wet Marcellus Shale production and Hornet Midstream owned a 15-mile, high-pressure gathering system in West Virginia that connects to the Eureka Midstream system. The Bolt-on Acquisition closed on April 10, 2019 and was funded through proceeds from the March 2019 private placement by EQM of an aggregate of 24,605,291 EQM Series A Preferred Units that closed concurrently with the Bolt-on Acquisition. At the closing of the Bolt-on Acquisition, a subsidiary of Hornet Midstream terminated all of its obligations under its term loan credit agreement and repaid the $28.2 million outstanding principal balance and $0.1 million in related interest and fees. The Company recorded $0.3 million and $17.0 million in acquisition-related expenses related to the Bolt-on Acquisition during the three and nine months ended September 30, 2019, respectively. The Bolt-on Acquisition acquisition-related expenses included $0.3 million for professional fees for the three months ended September 30, 2019 and $15.3 million for professional fees and $1.7 million for compensation arrangements for the nine months ended September 30, 2019, and are included in separation and other transaction costs in the statements of consolidated comprehensive income. The Bolt-on Acquisition was accounted for as a business combination using the acquisition method. As a result of the acquisition, the Company recognized $99.2 million of goodwill, which was allocated to the Gathering segment. Such goodwill primarily related to additional commercial opportunities, a diversified producer customer mix, increased exposure to dry Utica and wet Marcellus acreage and operating leverage within the Gathering segment. The purchase price allocation and related adjustments were finalized during the fourth quarter of 2019. The following table summarizes the final purchase price and allocation of the fair value of the assets acquired and liabilities assumed in the Bolt-on Acquisition as of April 10, 2019 by the Company, as well as certain measurement period adjustments made subsequent to the Company's initial valuation. (in thousands) Preliminary Purchase Price Allocation (As initially reported) Measurement Period Adjustments (a) Purchase Price Allocation (As adjusted) Consideration given: Cash consideration (b) $ 861,250 $ (11,404) $ 849,846 Buyout of portion of Eureka Midstream Class B Units and incentive compensation 2,530 — 2,530 Total consideration 863,780 (11,404) 852,376 Fair value of liabilities assumed: Current liabilities 52,458 (9,857) 42,601 Long-term debt 300,825 — 300,825 Other long-term liabilities 10,203 — 10,203 Amount attributable to liabilities assumed 363,486 (9,857) 353,629 Fair value of assets acquired: Cash 15,145 — 15,145 Accounts receivable 16,817 — 16,817 Inventory 12,991 (26) 12,965 Other current assets 882 — 882 Net property, plant and equipment 1,222,284 (8,906) 1,213,378 Intangible assets (c) 317,000 (6,000) 311,000 Deferred tax asset 5,773 (5,268) 505 Other assets 14,567 — 14,567 Amount attributable to assets acquired 1,605,459 (20,200) 1,585,259 Noncontrolling interests (486,062) 7,602 (478,460) Goodwill as of April 10, 2019 $ 107,869 $ (8,663) $ 99,206 Impairment of goodwill (d) (99,206) Goodwill as of September 30, 2020 $ — (a) The Company recorded measurement period adjustments to its preliminary acquisition date fair values due to the refinement of its valuation models, assumptions and inputs. The measurement period adjustments were based upon information obtained about facts and circumstances that existed at the acquisition date that, if known, would have affected the measurement of the amounts recognized at that date. (b) The cash consideration for the Bolt-on Acquisition was adjusted by approximately $11.4 million related to working capital adjustments and the release of all escrowed indemnification funds to EQM. (c) After considering the refinements to the valuation models, the Company estimated the fair value of the customer-related intangible assets acquired as part of the Bolt-on Acquisition to be $311.0 million. As a result, the fair value of the customer-related intangible assets was decreased by $6.0 million on September 30, 2019 with a corresponding increase to goodwill. In addition, the change to the provisional amount resulted in a decrease in amortization expense and accumulated amortization of approximately $0.4 million. (d) During the third quarter of 2019, the Company identified impairment indicators that suggested the fair value of its goodwill was more likely than not below its carrying amount. As such, the Company performed an interim goodwill impairment assessment, which resulted in the Company recognizing impairment to goodwill of approximately $268.1 million, of which $99.2 million was associated with its Eureka/Hornet reporting unit, bringing the reporting unit's goodwill balance to zero. See Note 4 for further detail. The estimated fair value of midstream facilities and equipment, generally consisting of pipeline systems and compression stations, was estimated using the cost approach. Significant unobservable inputs in the estimate of fair value under this approach included management's assumptions about the replacement costs for similar assets, the relative age of the acquired assets and any potential economic or functional obsolescence associated with the acquired assets. As a result, the estimated fair value of the midstream facilities and equipment represented a Level 3 fair value measurement. As a result of the acquisition, the noncontrolling interest in Eureka Midstream was estimated to be $478.5 million. The fair value of the noncontrolling interest was calculated based on the enterprise value of Eureka Midstream and the percentage ownership not acquired by the Company. Significant unobservable inputs in the enterprise value of Eureka Midstream include future revenue estimates and future cost assumptions. As a result, the fair value measurement is based on significant inputs that are not observable in the market and thus represents a Level 3 fair value measurement. As part of the preliminary purchase price allocation, the Company identified intangible assets for customer relationships with third-party customers. The fair value of the customer relationships with third-party customers was determined using the income approach, which requires a forecast of the expected future cash flows generated and an estimated market-based weighted average cost of capital. Significant unobservable inputs in the determination of fair value include future revenue estimates, future cost assumptions and estimated customer retention rates. As a result, the estimated fair value of the identified intangible assets represents a Level 3 fair value measurement. The Company calculates amortization of intangible assets using the straight-line method over the estimated useful life of the intangible assets. The Company previously utilized a useful life of 20 years for the Eureka Midstream- and Hornet Midstream-related intangible assets. As a result of expected changes in cash flows due to decreases in producer activity driven by lower natural gas prices, as of April 1, 2020, the Company prospectively changed the remaining useful life of the Eureka Midstream-related intangible assets to 10.75 years, increasing the expected annual amortization expense by $9.1 million. In addition, as a result of then expected reductions in future cash flows, as of October 1, 2019, the useful life of the Hornet Midstream-related intangible assets was prospectively changed to 7.25 years. The estimated annual amortization expense for the Eureka Midstream- and Hornet Midstream-related intangible assets for the remaining three months of 2020 and over the successive five years is as follows: 2020 $5.8 million, 2021 $23.3 million, 2022 $23.3 million, 2023 $23.3 million, 2024 $23.3 million and 2025 $23.3 million. As discussed in Note 4, during the third quarter of 2019, as a result of a recoverability test conducted due to a decrease in producer activity, the Company determined that the estimated fair value of the Hornet Midstream-related intangible assets was not in excess of the assets’ carrying value, which resulted in an impairment charge of $36.4 million related to certain of such intangibles within the Company’s Gathering segment. The Company also performed a recoverability test during the first quarter of 2020 due to significant declines in the unit price of EQM Common Units and corresponding market capitalization, which resulted in an additional impairment charge of $17.7 million to the Hornet Midstream-related intangible assets (see Note 4). The useful life of the Hornet Midstream-related intangible assets remained 7.25 years following the first quarter 2020 recoverability test.

Impairments of Long-Lived Asset

Impairments of Long-Lived Assets and Other-Than-Temporary Decline in Value	9 Months Ended
	Sep. 30, 2020
Property, Plant and Equipment [Abstract]
Impairments of Long-Lived Assets and Other-Than-Temporary Decline in Value	Impairments of Long-Lived Assets and Other-Than-Temporary Decline in Value Goodwill. On February 26, 2020 (the EQT Global GGA Effective Date), the Company (through EQM) entered into a Gas Gathering and Compression Agreement (as amended, the EQT Global GGA) with EQT for the provision of certain gas gathering services to EQT in the Marcellus and Utica Shales of Pennsylvania and West Virginia (as further discussed in Note 6). Prior to the EQT Global GGA Effective Date, the Company operated three reportable operating segments and seven reporting units, which are one level below the operating segment level and are generally based on how segment management reviews the Company's operating results. Commencing with the EQT Global GGA Effective Date, the Company reduced its reporting units from seven to six and maintained its three reportable operating segments. As of the EQT Global GGA Effective Date, the only reporting unit to which the Company had goodwill recorded related to the Pennsylvania gathering assets acquired in connection with EQM's merger with Rice Midstream Partners LP in July 2018 (RMP PA Gas Gathering reporting unit). As a result of the EQT Global GGA, the assets under, and operations associated with, the RMP PA Gas Gathering reporting unit and the reporting unit associated with the gas gathering and compression activities of EQM Gathering Opco, LLC, an indirect wholly owned subsidiary of the Company (EQM Opco reporting unit), were combined to service a collective MVC under the agreement. Therefore, effective on the EQT Global GGA Effective Date, the RMP PA Gas Gathering reporting unit was merged with and into the EQM Opco reporting unit, with the EQM Opco reporting unit surviving. During the first quarter of 2020, the Company identified impairment indicators in the form of significant declines in the unit price of EQM Common Units and corresponding market capitalization. Management considered these declines as indicators that the fair value of the RMP PA Gas Gathering reporting unit was more likely than not below its carrying amount, and the performance of an interim quantitative goodwill impairment assessment was required. Additionally, as a result of the combination of the RMP PA Gas Gathering reporting unit and the EQM Opco reporting unit, the Company tested both the RMP PA Gas Gathering and the merged EQM Opco reporting units for goodwill impairment. In estimating the fair value of the RMP PA Gas Gathering and the merged EQM Opco reporting units, the Company used a combination of the income approach and the market approach. The Company used the income approach’s discounted cash flow method, which applies significant inputs not observable in the public market (Level 3), including estimates and assumptions related to the use of an appropriate discount rate, future throughput volumes, operating costs, capital spending and changes in working capital. The Company used the market approach’s comparable company and reference transaction methods. The comparable company method evaluates the value of a company using metrics of other businesses of similar size and industry. The reference transaction method evaluates the value of a company based on pricing multiples derived from similar transactions entered into by similar companies. As a result of the interim assessment, the Company determined that the fair values of the RMP PA Gas Gathering reporting unit and the merged EQM Opco reporting unit, as applicable, were greater than their respective carrying values. No impairment to goodwill was recorded during the three months ended March 31, 2020. The Company believes the estimates and assumptions used in estimating its reporting units’ fair values are reasonable and appropriate; however, different assumptions and estimates could materially affect the calculated fair values of the RMP PA Gas Gathering reporting unit and the merged EQM Opco reporting unit and the resulting conclusions on impairment of goodwill, which could materially affect the Company’s results of operations and financial position. Additionally, actual results could differ from these estimates. Additional adverse changes in the future could reduce the underlying cash flows used to estimate the fair value of the merged EQM Opco reporting unit and could result in a decline in fair value that could trigger future impairment charges relating to the EQM Opco reporting unit. The three reporting units to which the Company had goodwill during 2019 were (i) the Ohio gathering assets acquired in connection with EQM’s acquisition of the outstanding limited liability company interests in each of EQM West Virginia Midstream LLC (EQM West Virginia), EQM Olympus Midstream LLC (EQM Olympus) and Strike Force Midstream Holdings LLC (Strike Force Holdings) (collectively, Rice Retained Midstream) (ii) RMP PA Gas Gathering and (iii) the Ohio and West Virginia gathering assets acquired in the Bolt-on Acquisition (Eureka/Hornet, collectively with Rice Retained Midstream and RMP PA Gas Gathering, the Reporting Units). During the third quarter of 2019, the Company identified impairment indicators in the form of significant declines in the unit price of EQM's Common Units and corresponding market capitalization, primarily as a result of continued suppressed natural gas prices and decreased producer drilling activity. Management considered these declines as indicators that the fair value of goodwill was more likely than not below the carrying amounts for the respective Reporting Units. As such, the performance of an interim goodwill impairment assessment was required. In estimating the fair value of each of the Reporting Units, the Company used a combination of the income approach and the market approach, both as described above. As of August 31, 2019, the Company determined that the fair value of Rice Retained Midstream was greater than its carrying value; however, the carrying values of RMP PA Gas Gathering and Eureka/Hornet were each greater than their respective fair values. As a result, the Company recognized impairment of goodwill of $168.9 million and $99.2 million on RMP PA Gas Gathering and Eureka/Hornet, respectively. The non-cash impairment charge is included in the impairments of long-lived assets line on the Company's statements of consolidated comprehensive income. Long-lived assets, including intangible assets and equity method investments. The Company evaluates long-lived assets, including related intangibles, for impairment when events or changes in circumstances indicate, in management's judgment, that the carrying value of such assets may not be recoverable. Asset recoverability is measured by comparing the carrying value of the asset or asset group with its expected future pre-tax undiscounted cash flows. These cash flow estimates require the Company to make projections and assumptions for many years into the future for pricing, demand, competition, operating cost and other factors. If the carrying amount exceeds the expected future undiscounted cash flows, the Company recognizes an impairment equal to the excess of net book value over fair value as determined by quoted market prices in active markets or present value techniques if quotes are unavailable. The determination of the fair value using present value techniques requires the Company to make projections and assumptions regarding the probability of a range of outcomes and the rates of interest used in the present value calculations. Any changes the Company makes to these projections and assumptions could result in significant revisions to its evaluation of recoverability of its property, plant and equipment and the recognition of additional impairments. As of March 31, 2020, the Company performed a recoverability test of the Hornet Midstream long-lived assets due to decreased producer activity. As a result of the recoverability test, management determined that the carrying value of the Hornet Midstream long-lived assets (which consisted of gathering assets and customer-related intangible assets) was not recoverable under ASC 360, Impairment Testing: Long-Lived Assets Classified as Held and Used . During the first quarter of 2020, the Company estimated the fair value of the Hornet Midstream asset group and determined that the fair value was not in excess of the assets’ carrying value, which resulted in impairment charges of approximately $37.9 million to the gathering assets and approximately $17.7 million to the customer-related intangible assets both within the Company’s Gathering segment. The non-cash impairment charges were recognized during the first quarter of 2020 and are included in the impairments of long-lived assets line on the statements of consolidated comprehensive income. During the third quarter of 2019, the Company assessed its long-lived asset groups for impairment due to the triggering events described in the goodwill impairment summary above. As a result of the recoverability test, management determined that the carrying value of certain long-lived assets associated with Eureka/Hornet (specifically, Hornet Midstream customer-related intangible assets) were not recoverable. The Company estimated the fair value of the Hornet Midstream-related intangible assets and determined that the fair value was not in excess of the assets’ carrying value, which resulted in an impairment charge of approximately $36.4 million related to certain of such intangible assets within the Company's Gathering segment. The non-cash impairment charge is included in the impairments of long-lived assets line on the statements of consolidated comprehensive income. During 2019, the Company reassessed its asset groupings for its regulated pipelines due to certain regulatory ratemaking policy changes affecting the regulated pipelines, changes in strategic focus and plans for segmentation of operations. Prior to the second quarter of 2019, the Company defined its regulated asset grouping to include the FERC-regulated transmission and storage assets, integrated with the low-pressure assets due to overlapping operations, a shared costs structure and similar ratemaking structures. During the second quarter of 2019, Equitrans L.P. reached a settlement related to its FERC Form 501-G report, which was focused solely on the Company’s FERC-regulated transmission and storage assets. Further, management increased its operational focus and emphasis on high-pressure gathering assets as illustrated by the consummation of the Bolt-on Acquisition. As a result of these regulatory changes and shift in operational focus, beginning with the second quarter of 2019, the Company grouped its FERC-regulated assets in two asset groupings: FERC-regulated transmission and storage assets and FERC-regulated low-pressure gathering assets. Upon the change in asset grouping, management evaluated whether any indicators of impairment were present and, in conjunction with the evaluation, the Company determined that the carrying values for the non-core FERC-regulated low-pressure gathering assets exceeded their undiscounted cash flows. Additionally, following the settlement related to the FERC Form 501-G report, management did not, and currently does not, plan to seek to recover the deficient cash flows through a future rate proceeding. The Company therefore estimated the fair values of FERC-regulated low-pressure gathering assets and determined that their fair values were not in excess of the assets’ carrying values, which resulted in recognized impairments of property and equipment of approximately $80.1 million during the second quarter of 2019 related to the assets within the Company's Gathering segment. As a result of the impairment, the assets carry no book value. The non-cash impairment charge is included in the impairments of long-lived assets line on the statements of consolidated comprehensive income. The Company is also required to evaluate its equity method investments, including investments in the MVP Joint Venture, to determine whether they are impaired under ASC 323, Investments - Equity Method and Joint Ventures . The standard for determining whether an impairment must be recorded under ASC 323 is whether there occurred an other-than-temporary decline in value. The evaluation and measurement of impairments under ASC 323 involves the same uncertainties as described above for long-lived assets that the Company owns directly and accounts for in accordance with ASC 360. The estimates that the Company makes with respect to its equity method investments are based upon assumptions that management believes are reasonable, and the impact of variations in these estimates or the underlying assumptions could be material. Additionally, if the projects in which the Company holds these investments recognize an impairment under ASC 360, the Company would record its proportionate share of that impairment loss and would evaluate its investment for an other-than-temporary decline in value under ASC 323. The Company evaluated its equity method investments, including investments in the MVP Joint Venture, as of September 30, 2020 and determined that there was not an other-than-temporary decline in value. There is risk that the carrying value of the Company's investments in the MVP Joint Venture may be impaired in the future. There are ongoing legal and regulatory matters that must be resolved favorably before the MVP and MVP Southgate projects

Financial Information by Busine

Financial Information by Business Segment	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Financial Information by Business Segment	Financial Information by Business Segment The Company reports its operations in three segments that reflect its three lines of business: Gathering, Transmission and Water. Gathering includes predominantly dry gas gathering systems of high-pressure gathering lines and FERC-regulated low-pressure gathering lines; Transmission includes FERC-regulated interstate pipelines and storage systems; and Water consists of the Company's water pipelines, impoundment facilities, pumping stations, take point facilities and measurement facilities. Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (Thousands) Revenues from customers: Gathering $ 232,651 $ 299,491 $ 764,229 $ 847,038 Transmission 93,329 87,299 288,869 289,926 Water 24,020 21,644 90,605 67,419 Total operating revenues $ 350,000 $ 408,434 $ 1,143,703 $ 1,204,383 Operating income (loss): Gathering (a) $ 129,186 $ (98,489) $ 400,647 $ 177,720 Transmission 63,460 59,690 201,714 207,684 Water 10,118 7,722 40,173 18,980 Headquarters (b) (2,255) (7,376) (24,646) (16,621) Total operating income (loss) $ 200,509 $ (38,453) $ 617,888 $ 387,763 Reconciliation of operating income (loss) to net income (loss): Equity income (c) $ 60,917 $ 44,448 $ 171,233 $ 112,293 Other income 21,864 70 39,006 2,637 Loss on early extinguishment of debt — — 24,864 — Net interest expense 86,411 65,606 219,960 188,268 Income tax expense 28,440 1,948 81,846 45,868 Net income (loss) $ 168,439 $ (61,489) $ 501,457 $ 268,557 (a) Impairments of long-lived assets of $298.7 million for the three months ended September 30, 2019 and $55.6 million and $378.8 million for the nine months ended September 30, 2020 and 2019, respectively, were included in Gathering operating income (loss). See Note 4 for further information. (b) Includes separation and other transaction costs and other unallocated corporate expenses. (c) Equity income is included in the Transmission segment. September 30, 2020 December 31, 2019 (Thousands) Segment assets: Gathering $ 7,743,615 $ 7,572,911 Transmission (a) 4,279,330 3,903,707 Water 208,899 202,440 Total operating segments 12,231,844 11,679,058 Headquarters, including cash 398,836 362,651 Total assets $ 12,630,680 $ 12,041,709 (a) The equity investments in the MVP Joint Venture are included in the Transmission segment. Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (Thousands) Depreciation: Gathering $ 44,648 $ 38,943 $ 126,915 $ 104,502 Transmission 13,659 13,347 40,787 38,474 Water 8,105 6,907 22,720 19,801 Headquarters 360 263 849 3,953 Total $ 66,772 $ 59,460 $ 191,271 $ 166,730 Capital expenditures for segment assets: Gathering (a) $ 90,452 $ 271,860 $ 303,063 $ 686,178 Transmission (b) 6,721 16,296 32,983 46,287 Water 2,530 13,466 8,377 31,490 Headquarters 447 1,068 3,234 6,787 Total (c) $ 100,150 $ 302,690 $ 347,657 $ 770,742 (a) Includes approximately $13.5 million and $37.1 million of capital expenditures related to the noncontrolling interest in Eureka Midstream for the three and nine months ended September 30, 2020, respectively, and includes approximately $6.7 million and $17.6 million of capital expenditures related to the noncontrolling interest in Eureka Midstream for the three and nine months ended September 30, 2019, respectively. (b) Transmission capital expenditures do not include capital contributions made to the MVP Joint Venture for the MVP and MVP Southgate projects of $65.6 million and $211.7 million for the three months ended September 30, 2020 and 2019, respectively, and $144.3 million and $512.9 million for the nine months ended September 30, 2020 and 2019, respectively. (c) The Company accrues capital expenditures when the work has been completed but the associated bills have not yet been paid. Accrued capital expenditures are excluded from the statements of consolidated cash flows until they are paid. The net impact of non-cash capital expenditures, including the effect of accrued capital expenditures, assumed capital expenditures associated with the Bolt-on Acquisition, transfers from inventory as assets are assigned to a project and capitalized share-based compensation costs, was $8.3 million and $(15.3) million for the three months ended September 30, 2020 and 2019, respectively, and $29.9 million and $(0.8) million for the nine months ended September 30, 2020 and 2019, respectively.

Revenue from Contracts with Cus

Revenue from Contracts with Customers	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Revenue from Contract with Customers	Revenue from Contracts with Customers For the three and nine months ended September 30, 2020 and 2019, all revenues recognized on the Company's statements of consolidated comprehensive income are from contracts with customers. As of September 30, 2020 and December 31, 2019, all receivables recorded on the Company's consolidated balance sheets represent performance obligations that have been satisfied and for which an unconditional right to consideration exists. Summary of Disaggregated Revenues. The tables below provide disaggregated revenue information by business segment. Three Months Ended September 30, 2020 Gathering Transmission Water Total (Thousands) Firm reservation fee revenues (a) $ 145,533 $ 84,612 $ 9,005 $ 239,150 Volumetric-based fee revenues 87,118 8,717 15,015 110,850 Total operating revenues $ 232,651 $ 93,329 $ 24,020 $ 350,000 Three Months Ended September 30, 2019 Gathering Transmission Water Total (Thousands) Firm reservation fee revenues $ 154,791 $ 81,990 $ 840 $ 237,621 Volumetric-based fee revenues 144,700 5,309 20,804 170,813 Total operating revenues $ 299,491 $ 87,299 $ 21,644 $ 408,434 Nine Months Ended September 30, 2020 Gathering Transmission Water Total (Thousands) Firm reservation fee revenues (a) $ 446,721 $ 267,973 $ 32,788 $ 747,482 Volumetric-based fee revenues 317,508 20,896 57,817 396,221 Total operating revenues $ 764,229 $ 288,869 $ 90,605 $ 1,143,703 Nine Months Ended September 30, 2019 Gathering Transmission Water Total (Thousands) Firm reservation fee revenues $ 431,520 $ 263,051 $ 4,531 $ 699,102 Volumetric-based fee revenues 415,518 26,875 62,888 505,281 Total operating revenues $ 847,038 $ 289,926 $ 67,419 $ 1,204,383 (a) For the three months ended September 30, 2020, firm reservation fee revenues associated with Gathering and Water included approximately $2.6 million and $1.9 million, respectively, of MVC unbilled revenues. For the nine months ended September 30, 2020, firm reservation fee revenues associated with Gathering and Water included approximately $13.7 million and $11.4 million, respectively, of MVC unbilled revenues. There were no MVC unbilled revenues associated with Gathering and Water during the three and nine months ended September 30, 2019. Contract Assets. The Company recognizes contract assets in instances where billing occurs subsequent to revenue recognition and the Company's right to invoice the customer is conditioned on something other than the passage of time. The Company's contract assets primarily consist of revenue recognized under contracts containing MVCs whereby management has concluded (i) it is probable there will be a MVC deficiency payment at the end of the then-current MVC period, which is typically the period beginning at the inception of such contracts through the successive twelve month periods after that date, and (ii) that a significant reversal of revenue recognized currently for the future MVC deficiency payment will not occur. As a result, the Company's contract assets related to the Company's future MVC deficiency payments are generally expected to be collected within the next twelve months and are included in other current assets in the Company's consolidated balance sheets until such time as the MVC deficiency payments are invoiced to the customer. The following table presents changes in the Company's unbilled revenue balance during the nine months ended September 30, 2020: Unbilled Revenue (Thousands) Balance as of January 1, 2020 $ — Revenue recognized in excess of amounts invoiced (a) 25,086 Minimum volume commitments invoiced (b) — Balance as of September 30, 2020 $ 25,086 (a) Revenues associated with unbilled MVCs are included in firm reservation fee revenues within the Gathering and Water segments, as described in the Summary of Disaggregated Revenues table above. (b) Unbilled revenues are transferred to accounts receivable once the Company has an unconditional right to consideration from the customer. Contract Liabilities. As of September 30, 2020, the Company's contract liabilities consist of deferred revenue associated with the EQT Global GGA, including advance payments from EQT associated with the Rate Relief Shares (as defined below) acquired by the Company as consideration for certain commercial terms and the initial fair value of the Henry Hub cash bonus payment provision (as defined below). The contract liabilities are classified as current or non-current according to when such amounts are expected to be recognized. As of September 30, 2020, the contract liabilities are classified as non-current as none of the deferred revenue is expected to be recognized in revenue during the next five years. Contracts requiring advance payments and the recognition of contract liabilities are evaluated to determine whether the advance payments provide the Company with a significant financing benefit. This determination requires significant judgment and is based on the combined effect of the expected length of time between when the Company transfers the promised good or service to the customer and when the customer pays for those goods or services and the prevailing interest rates. The Company has assessed the EQT Global GGA and determined that this agreement does not contain a significant financing component. The following table presents changes in the Company's deferred revenue balances during the nine months ended September 30, 2020: Deferred Revenue (Thousands) Balance as of January 1, 2020 $ — Amounts recorded during the period (a) 321,775 Amounts transferred during the period (b) — Balance as of September 30, 2020 $ 321,775 (a) Includes deferred billed revenue of approximately $74.6 million and $148.8 million recorded during the three and nine months ended September 30, 2020, respectively, associated with the EQT Global GGA. (b) Deferred revenues are recognized as revenue upon satisfaction of the Company's performance obligation to the customer. Summary of Remaining Performance Obligations. The following table summarizes the estimated transaction price allocated to the Company's remaining performance obligations under all contracts with firm reservation fees and MVCs as of September 30, 2020 that the Company will invoice or transfer from contract liabilities and recognize in future periods. 2020 (a) 2021 2022 2023 2024 Thereafter Total (Thousands) Gathering firm reservation fees $ 22,081 $ 106,127 $ 158,721 $ 158,628 $ 157,127 $ 1,433,923 $ 2,036,607 Gathering revenues supported by MVCs 125,591 526,413 585,384 617,532 635,649 5,367,726 7,858,295 Transmission firm reservation fees 94,112 360,242 380,890 342,566 282,962 2,609,294 4,070,066 Water revenues supported by MVCs 9,006 16,521 60,000 60,000 60,000 105,000 310,527 Total (b) $ 250,790 $ 1,009,303 $ 1,184,995 $ 1,178,726 $ 1,135,738 $ 9,515,943 $ 14,275,495 (a) October 1, 2020 through December 31, 2020. (b) Includes assumptions regarding timing for placing certain projects, including the MVP, in-service. Delays in the in-service dates for projects may substantially alter the remaining performance obligations for certain contracts with firm reservation fees and/or MVCs. Based on total projected contractual revenues, including projected contractual revenues from future capacity expected from expansion projects that are not yet fully constructed for which the Company has executed firm contracts, the Company's firm gathering contracts and firm transmission and storage contracts had weighted average remaining terms of approximately 15 years and 14 years, respectively, as of September 30, 2020. EQT Global GGA. On the EQT Global GGA Effective Date, the Company (through EQM) entered into the EQT Global GGA with EQT for the provision by the Company of certain gas gathering services to EQT in the Marcellus and Utica Shales of Pennsylvania and West Virginia. Pursuant to the EQT Global GGA, EQT is subject to an initial annual MVC of 3.0 Bcf per day that gradually steps up to 4.0 Bcf per day for several years following the in-service date of the MVP. The EQT Global GGA runs from the EQT Global GGA Effective Date through December 31, 2035, and will renew annually thereafter unless terminated by EQT or the Company pursuant to its terms. Pursuant to the EQT Global GGA, the Company has certain obligations to build connections to connect EQT wells to its gathering system, which are subject to geographical limitations in relation to the dedicated area in Pennsylvania and West Virginia, as well as the distance of such connections to the Company's then-existing gathering system. Management has estimated the total consideration expected to be received over the life of the EQT Global GGA, including gathering MVC revenue with a declining rate structure, the fair value of the Rate Relief Shares and the initial fair value of the Henry Hub cash bonus payment provision. The total consideration is allocated proportionally to the performance obligation under the contract, which is to provide daily MVC capacity over the life of the contract, in order to recognize revenue in accordance with ASC 606, Revenue from Contracts with Customers. The performance obligations will be satisfied during the life of the contract based on a units of production methodology for the daily MVC capacity provided to EQT. Due to the declining rate structure, there will be periods during which the billable gathering MVC revenue will exceed the allocated consideration to the performance obligation, which will result in billable gathering MVC revenue being deferred to the contract liability. The deferred consideration amounts are deferred until recognized in revenue when the associated performance obligation has been satisfied and are classified as current or non-current according to when such amounts are expected to be recognized. In addition to the estimated total consideration allocated to the daily MVC, the EQT Global GGA includes other fees based on variable or volumetric-based services that will be recognized in the period the services are provided. The EQT Global GGA provides for potential cash bonus payments payable by EQT to the Company during the period beginning on the first day of the calendar quarter in which the MVP in-service date occurs through the earlier of the twelfth calendar quarter from that point or the calendar quarter ending December 31, 2024 (the Henry Hub cash bonus payment provision). The potential cash bonus payments are conditioned upon the quarterly average of certain Henry Hub natural gas prices exceeding certain price thresholds. The Henry Hub cash bonus payment provision meets the definition of an embedded derivative that should be bifurcated from the host contract and accounted for separately in accordance with ASC 815, Derivatives and Hedging . The embedded derivative was recorded as a derivative asset at its estimated fair value at inception of approximately $51.5 million and as part of the contract liability to be included in the total consideration to be allocated to the performance obligation under ASC 606. Subsequent changes to the fair value of the derivative instrument through the end of the contract are recognized in other income on the Company's statements of consolidated comprehensive income. The gathering MVC fees payable by EQT (or its affiliates) to the Company set forth in the EQT Global GGA are subject to potential reductions for certain contract years as set forth in the EQT Global GGA, conditioned upon the in-service date of the MVP, which provide for estimated aggregate fee relief of approximately $270 million in the first year after the in-service date of the MVP, approximately $230 million in the second year after the in-service date of the MVP and approximately $35 million in the third year after the in-service date of the MVP. In addition, if the MVP in-service date has not occurred by January 1, 2022, EQT has an option, exercisable for a period of twelve months (or such shorter period if the in-service date of the MVP occurs), to forgo approximately $145 million of the gathering fee relief in the first year after the MVP in-service date and approximately $90 million of the gathering fee relief in the second year after the MVP in-service date in exchange for a cash payment from the Company (through EQM) to EQT in the amount of approximately $196 million (the EQT Cash Option). As consideration for the additional rate relief subject to the EQT Cash Option, the Company purchased shares of its common stock (see Rate Relief Shares discussed and defined below) from EQT. The consideration received for future contractual rate relief associated with the Rate Relief Shares was recorded at a fair value of approximately $121.5 million as a contract liability in accordance with ASC 606 and will be recognized as revenue over the life of the contract. Water Services Letter Agreement. On February 26, 2020, the Company (through EQM) entered into a letter agreement with EQT, pursuant to which EQT agreed to utilize the Company for the provision of water services in Pennsylvania under existing water services agreements and new water services agreements if negotiated between the parties (such letter agreement, the Water Services Letter Agreement). The Water Services Letter Agreement is effective as of the first day of the first month following the MVP in-service date and shall expire on the fifth anniversary of such date. During each year of the Water Services Letter Agreement, EQT agreed that fixed MVC fees payable to the Company for water services incurred on a volumetric basis, provided in accordance with existing agreements and new agreements entered into between the parties pursuant to the Water Services Letter Agreement (or the related agreements), shall be equal to or greater than $60 million per year.

Related Party Transactions

Related Party Transactions	9 Months Ended
	Sep. 30, 2020
Related Party Transactions [Abstract]
Related Party Transactions	Related Party Transactions Related Party Transactions with EQT As of September 30, 2020, EQT remained a related party of the Company due to its ownership of 25,296,026 shares of Equitrans Midstream common stock, which represented an approximately 5.9% ownership interest in the Company, excluding the impact of the Equitrans Midstream Preferred Shares. In the ordinary course of business, the Company engaged, and continues to engage, as applicable, in transactions with EQT and its affiliates, including, but not limited to, gathering agreements, transportation service and precedent agreements, storage agreements and water services agreements. Operating revenues included related party revenues from EQT of approximately $222.7 million and $275.4 million for the three months ended September 30, 2020 and 2019, respectively, and $741.2 million and $843.9 million for the nine months ended September 30, 2020 and 2019, respectively. Operating and maintenance expense included charges to EQT of approximately $2.4 million for both the three and nine months ended September 30, 2019. Selling, general and administrative expense included charges from EQT of approximately $1.0 million for both the three and nine months ended September 30, 2019. Additionally, net interest expense included interest income on the Preferred Interest in EES of approximately $1.5 million and $1.6 million for the three months ended September 30, 2020 and 2019, respectively, and $4.6 million and $4.8 million for the nine months ended September 30, 2020 and 2019, respectively. Accounts receivable as of September 30, 2020 and December 31, 2019 included approximately $194.3 million and $175.2 million, respectively, of related party accounts receivable from EQT. Other current assets as of September 30, 2020 included approximately $11.4 million of MVC unbilled revenue from EQT. In addition, as of September 30, 2020, the Preferred Interest in EES was approximately $106.3 million, of which $5.2 million was recorded in other current assets and $101.1 million was recorded in other assets on the Company's consolidated balance sheets. As of December 31, 2019, the Preferred Interest in EES was approximately $110.1 million, of which $5.0 million was recorded in other current assets and $105.1 million was recorded in other assets on the Company's consolidated balance sheets. Tax Matters Agreement. On November 12, 2018, in connection with the Separation and Distribution, the Company and EQT entered into a tax matters agreement that governs the parties' respective rights, responsibilities and obligations with respect to taxes (including taxes arising in the ordinary course of business and taxes, if any, incurred as a result of any failure of the Distribution and certain related transactions to qualify as generally tax-free for U.S. federal income tax purposes), tax attributes, the preparation and filing of tax returns, the control of audits and other tax proceedings and assistance and cooperation with respect to tax matters (the Tax Matters Agreement). In addition, the Tax Matters Agreement imposes certain restrictions on the Company and its subsidiaries, including restrictions on certain equity issuances, business combinations, sales of assets and similar transactions, that are designed to preserve the tax-free status of the Distribution and certain related transactions. The Tax Matters Agreement provides special rules that allocate tax liabilities in the event that the Distribution, together with certain related transactions, is not tax-free. In general, under the Tax Matters Agreement, each party is expected to be responsible for any taxes, whether imposed on the Company or EQT, that arise (i) from the failure of the Distribution, together with certain related transactions, to qualify for tax-free treatment, or (ii) if certain related transactions were to fail to qualify for their intended tax treatment, in each case, to the extent that the failure to qualify is attributable to actions, events or transactions relating to such party's respective stock, assets or business or a breach of the relevant representations or covenants made by that party in the Tax Matters Agreement. Credit Letter Agreement. On February 26, 2020, in connection with the execution of the EQT Global GGA, the Company (through EQM) and EQT entered into a letter agreement (the Credit Letter Agreement) pursuant to which, among other things, (a) the Company agreed to relieve certain credit posting requirements for EQT, in an amount up to approximately $250 million, under its commercial agreements with the Company, subject to EQT maintaining a minimum credit rating from two of three rating agencies of (i) Ba3 with Moody’s Investors Service (Moody's), (ii) BB- with S&P Global Ratings (S&P) and (iii) BB- with Fitch Investor Services (Fitch) and (b) the Company agreed to use commercially reasonable good faith efforts to negotiate similar credit support arrangements for EQT in respect of its commitments to the MVP Joint Venture. EQT Global GGA. See Notes 4 and 6 for further detail. Water Services Letter Agreement. See Note 6 for further detail. Share Purchase Agreements. See Note 6 for further detail.

Investments in Unconsolidated E

Investments in Unconsolidated Entity	9 Months Ended
	Sep. 30, 2020
Equity Method Investments and Joint Ventures [Abstract]
Investments in Unconsolidated Entity	Investments in Unconsolidated EntityThe MVP Joint Venture is constructing the MVP, an estimated 300-mile natural gas interstate pipeline that will span from northern West Virginia to southern Virginia. The Company will operate the MVP and owned a 45.9% interest in the MVP project as of September 30, 2020. On November 4, 2019, Con Edison exercised an option to cap its investment in the MVP project at approximately $530 million (excluding AFUDC). The Company and NextEra Energy, Inc. are obligated to, and RGC Resources, Inc., another member of the MVP Joint Venture owning an interest in the MVP project, has opted to, fund the shortfall in Con Edison's capital contributions, on a pro rata basis. Such funding by the Company and funding by other members has and will correspondingly increase the Company's and such other funding members' respective interests in the MVP project and decrease Con Edison's interest in the MVP project. As a result, based on the midpoint of the project's $5.8 billion to $6.0 billion (excluding AFUDC) targeted cost, the Company's equity ownership in the MVP project will progressively increase from approximately 45.9% to approximately 47.6%. The MVP Joint Venture is a variable interest entity because it has insufficient equity to finance its activities during the construction stage of the project. The Company is not the primary beneficiary of the MVP Joint Venture because the Company does not have the power to direct the activities that most significantly affect the MVP Joint Venture's economic performance. Certain business decisions, such as decisions to make distributions of cash, require a greater than 66 2/3% ownership interest approval, and no one member owns more than a 66 2/3% interest. In April 2018, the MVP Joint Venture announced the MVP Southgate project, a proposed 75-mile interstate pipeline that will extend from the MVP at Pittsylvania County, Virginia to new delivery points in Rockingham and Alamance Counties, North Carolina. The Company will operate the MVP Southgate pipeline and owned a 47.2% interest in the MVP Southgate project as of September 30, 2020. In September 2020, the MVP Joint Venture issued a capital call notice for the funding of the MVP project to MVP Holdco, LLC (MVP Holdco), a wholly owned subsidiary of the Company, for $126.6 million, of which $14.4 million and $112.2 million was paid in October 2020 and November 2020, respectively. In September 2020, the MVP Joint Venture issued a capital call notice for the funding of the MVP Southgate project to MVP Holdco for $0.7 million, which was paid in October 2020. In addition, in October 2020, the MVP Joint Venture issued a capital call notice for the funding of the MVP Southgate project to MVP Holdco for $0.3 million, which is expected to be paid in November 2020. The capital contributions payable and the corresponding increase to the investment balance are reflected on the consolidated balance sheet as of September 30, 2020. The Company's interests in the MVP and MVP Southgate projects are equity method investments for accounting purposes because the Company has the ability to exercise significant influence, but not control, over the MVP Joint Venture's operating and financial policies. Accordingly, the Company records adjustments to the investment balance for contributions to or distributions from the MVP Joint Venture and for the Company's pro-rata share of MVP Joint Venture earnings. Equity income, which is primarily related to the Company's pro-rata share of the MVP Joint Venture's AFUDC on the construction of the MVP, is reported in equity income in the Company's statements of consolidated comprehensive income. Pursuant to the MVP Joint Venture's limited liability company agreement, MVP Holdco is obligated to provide performance assurances, which may take the form of a guarantee from EQM (provided that EQM's debt is rated as investment grade in accordance with the requirements of the MVP Joint Venture's limited liability company agreement), a letter of credit or cash collateral, in favor of the MVP Joint Venture to provide assurance as to the funding of MVP Holdco's proportionate share of the construction budget for the MVP project. In 2019, EQM issued performance guarantees in an amount equal to 33% of MVP Holdco's proportionate share of the then-remaining construction budget for the MVP project. As of December 31, 2019, EQM's performance guarantee was approximately $223 million, adjusted for capital contributions made by EQM during the fourth quarter of 2019. In addition, pursuant to the MVP Joint Venture's limited liability company agreement, MVP Holdco is obligated to provide performance assurances in respect of MVP Southgate, which performance assurances may take the form of a guarantee from EQM (provided that EQM's debt is rated as investment grade in accordance with the requirements of the MVP Joint Venture's limited liability company agreement), a letter of credit or cash collateral. In 2019, EQM issued a performance guarantee of $14 million in favor of the MVP Joint Venture for the MVP Southgate project. As a result of EQM’s credit rating downgrades in the first quarter of 2020, EQM delivered replacement credit support to the MVP Joint Venture in the form of letters of credit in the amounts of approximately $220.2 million and $14.2 million with respect to the MVP project and MVP Southgate project, respectively. In connection with delivering such letters of credit as replacement performance assurances, EQM's performance guarantees associated with the MVP and MVP Southgate projects were terminated. As of September 30, 2020, the letters of credit with respect to the MVP project and MVP Southgate project were in the amounts of approximately $220.2 million and $14.2 million, respectively. As of November 3, 2020, based on the midpoint of the targeted project cost, MVP Holdco's obligation to deliver a replacement letter of credit with respect to the MVP project was in the amount of approximately $231.2 million. Upon the FERC’s initial release to begin construction of the MVP Southgate project, the Company’s current letter of credit to support MVP Southgate will be terminated, and the Company will be obligated to deliver a new letter of credit (or provide another allowable form of performance assurance) in an amount equal to 33% of MVP Holdco’s proportionate share of the remaining capital obligations for the MVP Southgate project under the applicable construction budget. As of September 30, 2020, the Company's maximum financial statement exposure related to the MVP Joint Venture was approximately $2,829 million, which consisted of the investment in unconsolidated entity balance on the consolidated balance sheet as of September 30, 2020, net of capital contributions payable, and the letters of credit outstanding under the Amended EQM Credit Facility. As of November 3, 2020, in conjunction with MVP Holdco's obligation to deliver a replacement letter of credit with respect to the MVP project, the Company's maximum financial statement exposure related to the MVP Joint Venture was approximately $2,967 million. The following tables summarize the unaudited condensed consolidated financial statements of the MVP Joint Venture in relation to the MVP project. Condensed Consolidated Balance Sheets September 30, 2020 December 31, 2019 (Thousands) Current assets $ 290,541 $ 102,638 Non-current assets 5,540,846 4,951,521 Total assets $ 5,831,387 $ 5,054,159 Current liabilities $ 187,826 $ 223,645 Equity 5,643,561 4,830,514 Total liabilities and equity $ 5,831,387 $ 5,054,159 Condensed Statements of Consolidated Operations Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (Thousands) Environmental remediation reserve $ 20 $ (516) $ (295) $ (2,682) Other income 13 1,165 275 5,863 Net interest income 39,280 29,100 110,868 73,035 AFUDC — equity 91,653 67,902 258,693 170,416 Net income $ 130,966 $ 97,651 $ 369,541 $ 246,632

Debt

Debt	9 Months Ended
	Sep. 30, 2020
Debt Disclosure [Abstract]
Debt	Debt Equitrans Midstream Term Loan Facility . In December 2018, Equitrans Midstream entered into a term loan credit agreement (as amended in May 2019, the ETRN Term Loan Credit Agreement) that provided for a senior secured term loan facility in an aggregate principal amount of $600 million (the ETRN Term Loans). The Company received net proceeds from the ETRN Term Loans of $568.1 million, inclusive of a discount of $18.0 million and estimated debt issuance costs of $13.9 million. The net proceeds were primarily used to fund the purchase of the public EQGP Common Units (the EQGP Buyout), including certain fees, costs and expenses in connection therewith, and the remainder was used for general corporate purposes. On March 3, 2020, EQM drew $650.0 million under the Amended EQM Credit Facility and transferred such funds to the Company, pursuant to a senior unsecured term loan agreement with the Company. The Company utilized a portion of such funds to pay off amounts outstanding under the ETRN Term Loans and the ETRN Term Loan Credit Agreement was terminated. As a result, the Company wrote off $24.4 million of unamortized discount and financing costs related to the ETRN Term Loan Credit Agreement. The write off charge is included in the loss on early extinguishment of debt line on the statements of consolidated comprehensive income. On September 29, 2020, the Company made a prepayment to EQM of all principal, interest, fees and other obligations outstanding under the senior unsecured term loan agreement and terminated the agreement. As of December 31, 2019, the current portion of the ETRN Term Loans was $6.0 million and was recorded in the current portion of long-term debt on the consolidated balance sheet. The Company had $594.0 million of borrowings outstanding and no letters of credit outstanding under the ETRN Term Loan Credit Agreement as of December 31, 2019. During the period from January 1, 2020 to March 3, 2020, the weighted average annual interest rate was approximately 6.2%. For the three and nine months ended September 30, 2019, the weighted average annual interest rates were approximately 6.8% and 6.9%, respectively. Equitrans Midstream Credit Facility. In October 2018, Equitrans Midstream entered into a senior secured revolving credit facility agreement that provided for $100 million in borrowing capacity (the Equitrans Midstream Credit Facility). Equitrans Midstream amended the Equitrans Midstream Credit Facility on December 31, 2018 to, among other things, permit the incurrence of the borrowings under the ETRN Term Loan Credit Agreement. The Equitrans Midstream Credit Facility, which was available for general corporate purposes and to fund ongoing working capital requirements, was terminated on March 3, 2020 in conjunction with the Company's termination of the ETRN Term Loan Credit Agreement (see above). As a result, the Company wrote off $0.5 million of unamortized financing costs related to the Equitrans Midstream Credit Facility. The write off charge is included in the loss on early extinguishment of debt line on the statements of consolidated comprehensive income. The Company had no borrowings and no letters of credit outstanding under the Equitrans Midstream Credit Facility as of December 31, 2019 and during the period from January 1, 2020 to March 3, 2020. There were no borrowings on the Equitrans Midstream Credit Facility during the three months ended September 30, 2019. For the nine months ended September 30, 2019, the maximum outstanding borrowings was approximately $44 million, the average daily balance was approximately $4 million and the weighted average annual interest rate was approximately 4.3%. Commitment fees paid to maintain credit availability under the credit facility were approximately $0.1 million for the period from January 1, 2020 to March 3, 2020, and approximately $0.1 million and $0.3 million for the three and nine months ended September 30, 2019, respectively. Amended EQM Revolving Credit Facility and Amended 2019 EQM Term Loan Agreement. On October 31, 2018, EQM amended and restated its unsecured revolving credit facility to increase the borrowing capacity from $1 billion to $3 billion and extend the term to October 2023 (the EQM Credit Facility). In August 2019, EQM entered into a term loan agreement (the 2019 EQM Term Loan Agreement) that provided for unsecured term loans (the EQM Term Loans) in an aggregate principal amount of $1.4 billion. Additionally, on March 30, 2020, EQM entered into (i) an amendment to the EQM Credit Facility (as amended, the Amended EQM Credit Facility) and (ii) an amendment to the 2019 EQM Term Loan Agreement (as amended, the Amended 2019 EQM Term Loan Agreement) which, among other things, amended certain defined terms and negative covenants in the EQM Credit Facility and the 2019 EQM Term Loan Agreement. The Amended EQM Credit Facility is available for general partnership purposes, including to purchase assets, to fund working capital requirements and capital expenditures and to pay distributions. Subject to satisfaction of certain conditions, the Amended EQM Credit Facility has an accordion feature that allows EQM to increase the available borrowings under the facility by up to an additional $750 million. The Amended EQM Credit Facility has a sublimit of up to $250 million for same-day swing line advances and a sublimit of up to $400 million for letters of credit. In addition, EQM has the ability to request that one or more lenders make available term loans under the Amended EQM Credit Facility, subject to the satisfaction of certain conditions. As of September 30, 2020, no term loans were outstanding under the Amended EQM Credit Facility. Such term loans would be secured by cash, qualifying investment grade securities or a combination thereof. Under the terms of the Amended EQM Credit Facility, EQM can obtain committed loans as Base Rate Loans (as defined in the Amended EQM Credit Facility) or Eurodollar Rate Loans (as defined in the Amended EQM Credit Facility). Base Rate Loans are denominated in dollars and bear interest at a base rate plus a margin of 0.125% to 1.750% determined on the basis of a combination of EQM’s then-current debt issuer credit ratings by Moody’s, S&P and Fitch. Eurodollar Rate Loans bear interest at a Eurodollar Rate (as defined in the Amended EQM Credit Facility) plus a margin of 1.125% to 2.750% determined on the basis of a combination of EQM’s then-current debt issuer credit ratings with Moody’s, S&P and Fitch. EQM may voluntarily prepay its borrowings under the Amended EQM Credit Facility, in whole or in part, without premium or penalty, but subject to reimbursement of funding losses with respect to certain prepayments of Eurodollar Rate Loans. Revolving amounts prepaid under the Amended EQM Credit Facility may be re-borrowed. As of September 30, 2020, EQM had approximately $485 million of borrowings and $235 million of letters of credit outstanding under the Amended EQM Credit Facility. As of December 31, 2019, EQM had approximately $610 million of borrowings and $1 million of letters of credit outstanding under the Amended EQM Credit Facility. During the three and nine months ended September 30, 2020, the maximum outstanding borrowings at any time were approximately $485 million and $2,040 million, respectively, and the average daily balances were approximately $485 million and $975 million, respectively. EQM incurred interest at weighted average annual interest rates of approximately 2.6% and 2.9% for the three and nine months ended September 30, 2020, respectively. During the three and nine months ended September 30, 2019, the maximum outstanding borrowings at any time was approximately $1,690 million for both periods, the average daily balances were approximately $865 million and $950 million, respectively, and the weighted average annual interest rates were approximately 3.7% and 3.8%, respectively. For the three and nine months ended September 30, 2020, commitment fees of $2.4 million and $5.0 million, respectively, were paid to maintain credit availability under the Amended EQM Credit Facility. For the three and nine months ended September 30, 2019, commitment fees of $1.2 million and $3.3 million, respectively, were paid to maintain credit availability under the Amended EQM Credit Facility. The EQM Term Loans mature in August 2022. EQM received net proceeds from the issuance of the EQM Term Loans of $1,397.4 million, inclusive of debt issuance costs of $2.6 million. The net proceeds were primarily used to repay borrowings under the Amended EQM Credit Facility and the remainder was used for general partnership purposes. The Amended 2019 EQM Term Loan Agreement provides EQM with the right to request incremental term loans in an aggregate amount of up to $300 million, subject to, among other things, obtaining additional commitments from existing lenders or commitments from new lenders. As of September 30, 2020 and December 31, 2019, EQM had $1.4 billion of borrowings outstanding under the Amended 2019 EQM Term Loan Agreement for both periods. During the three and nine months ended September 30, 2020, the weighted average annual interest rates for the periods were approximately 2.4% and 2.8%, respectively. During the applicable portion of the two months ended September 30, 2019, the weighted average annual interest rate for the period was approximately 3.6%. Under the terms of the Amended 2019 EQM Term Loan Agreement, EQM can obtain Base Rate Loans (as defined in the Amended 2019 EQM Term Loan Agreement) or Eurodollar Rate Loans (as defined in the Amended 2019 EQM Term Loan Agreement). Base Rate Loans are denominated in dollars and bear interest at a base rate plus a margin of 0.000% to 1.625% determined on the basis of a combination of EQM’s then-current debt issuer credit ratings with Moody’s, S&P and Fitch. Eurodollar Rate Loans bear interest at a Eurodollar Rate (as defined in the Amended 2019 EQM Term Loan Agreement) plus a margin of 1.000% to 2.625% determined on the basis of a combination of EQM’s then-current debt issuer credit ratings with Moody’s, S&P and Fitch. EQM may voluntarily prepay its borrowings under the Amended 2019 EQM Term Loan Agreement, in whole or in part, without premium or penalty, but subject to reimbursement of funding losses with respect to certain prepayments of Eurodollar Rate Loans. Amounts prepaid under the Amended 2019 EQM Term Loan Agreement may not be reborrowed. The Amended EQM Credit Facility and the Amended 2019 EQM Term Loan Agreement each contain certain negative covenants, that, among other things, limit the ability of EQM and certain of its subsidiaries to incur or permit liens on assets, establish a maximum consolidated leverage ratio that varies over the course of the term ranging from not more than 5.75 to 1.00 to not more than 5.00 to 1.00 tested as of the end of each fiscal quarter (which in limited circumstances is increased for certain measurement periods following the consummation of certain acquisitions), limit transactions with affiliates, mergers and other fundamental changes, asset dispositions, the incurrence of new debt and entry into burdensome agreements, in each case and as applicable, subject to certain specified exceptions. The Amended EQM Credit Facility and the Amended 2019 EQM Term Loan Agreement each also contains certain specified events of default, including, among others, failure to make certain payments (subject to specified grace periods in some cases), failure to observe covenants (subject to specified grace periods in some cases), cross-defaults to certain other material debt, certain specified insolvency or bankruptcy events and the occurrence of a change of control event, in each case, the occurrence of which would allow the lenders to accelerate EQM’s payment obligations under the Amended EQM Credit Facility or the Amended 2019 EQM Term Loan Agreement, as applicable. Eureka Credit Facility. Eureka Midstream, LLC (Eureka), a wholly owned subsidiary of Eureka Midstream, has a $400 million senior secured revolving credit facility that is available for general business purposes, including financing maintenance and expansion capital expenditures related to the Eureka system and providing working capital for Eureka’s operations (as amended, the Eureka Credit Facility). The Eureka Credit Facility matures on August 25, 2021. Subject to satisfaction of certain conditions, the Eureka Credit Facility has an accordion feature that allows Eureka to increase the available borrowings under the facility to an amount no greater than $500 million. As of September 30, 2020 and December 31, 2019, Eureka had approximately $303 million and $293 million, respectively, of borrowings outstanding under the Eureka Credit Facility. For the three and nine months ended September 30, 2020, the maximum amount of outstanding borrowings under the Eureka Credit Facility at any time was approximately $323 million for both periods, the average daily balances were approximately $310 million and $300 million, respectively, and Eureka incurred interest at weighted average annual interest rates of approximately 2.4% and 2.6%, respectively. For the three months ended September 30, 2019 and for the period from April 10, 2019 through September 30, 2019, the maximum amount of outstanding borrowings under the Eureka Credit Facility at any time was approximately $293 million for both periods, the average daily balances were approximately $293 million and $285 million, respectively, and Eureka incurred interest at a weighted average annual interest rate of approximately 4.3% for both periods. For the three and nine months ended September 30, 2020, commitment fees of $0.1 million and $0.4 million, respectively, were paid to maintain credit availability under the Eureka Credit Facility. For the three months ended September 30, 2019 and for the period from April 10, 2019 through September 30, 2019, commitment fees of $0.1 million and $0.2 million, respectively, were paid to maintain credit availability under the Eureka Credit Facility. 2020 Senior Notes. During the second quarter of 2020, EQM issued $700 million aggregate principal amount of new 6.000% senior unsecured notes due July 1, 2025 and $900 million aggregate principal amount of new 6.500% senior unsecured notes due July 1, 2027 (collectively, the 2020 Senior Notes) and received net proceeds from the offering of approximately $1,576.1 million, inclusive of a discount of $20.0 million and debt issuance costs of $3.9 million. The net proceeds were used to repay a portion of the borrowings outstanding under the Amended EQM Credit Facility, and the remainder was used for general partnership purposes. The 2020 Senior Notes were issued under and are governed by an indenture, dated June 18, 2020 (the 2020 Indenture), between EQM and the Bank of New York Mellon Trust Company, N.A., as trustee. The 2020 Indenture contains covenants that limit EQM's ability to, among other things, incur certain liens securing indebtedness, engage in certain sale and leaseback transactions, and enter into certain consolidations, mergers, conveyances, transfers or leases of all or substantially all of EQM's assets. Upon the occurrence of a Change of Control Triggering Event (as defined in the 2020 Indenture), EQM may be required to offer to purchase the 2020 Senior Notes at a purchase price equal to 101% of the aggregate principal amount of the 2020 Senior Notes repurchased, plus accrued and unpaid interest, if any, to, but excluding, the repurchase date. The 2020 Senior Notes are unsecured and rank equally with all of EQM’s existing and future senior obligations. The 2020 Senior Notes are senior in right of payment to any of EQM’s future obligations that are, by their terms, expressly subordinated in right of payment to the 2020 Senior Notes. The 2020 Senior Notes are effectively subordinated to EQM’s secured obligations, if any, to the extent of the value of the collateral securing such obligations, and structurally subordinated to all indebtedness and obligations, including trade payables, of EQM’s subsidiaries, other than any subsidiaries that may guarantee the 2020 Senior Notes in the future. As of September 30, 2020, EQM and Eureka were in compliance with all debt provisions and covenants.

Fair Value Measurements

Fair Value Measurements	9 Months Ended
	Sep. 30, 2020
Fair Value Disclosures [Abstract]
Fair Value Measurements	Fair Value Measurements Assets Measured at Fair Value on a Recurring Basis. The Company records derivative instruments at fair value on a gross basis in its consolidated balance sheets. The Henry Hub cash bonus payment provision, as described in Note 6, is recorded at its estimated fair value using a Monte Carlo simulation model. Significant inputs used in the fair value measurement include NYMEX Henry Hub natural gas futures prices as of the date of valuation, risk-free interest rates based on U.S. Treasury rates, expected volatility of NYMEX Henry Hub natural gas futures prices and an estimated credit spread of EQT. The expected volatility of NYMEX Henry Hub natural gas futures prices used in the valuation methodology represents a significant unobservable input causing the Henry Hub cash bonus payment provision to be designated as a Level 3 fair value measurement. As of September 30, 2020, the fair value of the Henry Hub cash bonus payment provision was $89.2 million, of which $35.3 million was recorded in other current assets and $53.9 million was recorded in other assets on the Company's consolidated balance sheets. During the three and nine months ended September 30, 2020, the Company recognized gains of $21.0 million and $37.7 million, respectively, representing the change in estimated fair value of the derivative instrument during the applicable period. The gain is reflected in other income in the Company's statements of consolidated comprehensive income. Other Financial Instruments. The carrying values of cash and cash equivalents, accounts receivable, amounts due to/from related parties and accounts payable approximate fair value due to the short maturity of the instruments; as such, their fair values are Level 1 fair value measurements. The carrying values of borrowings under the Amended EQM Credit Facility, the Eureka Credit Facility and the Amended 2019 EQM Term Loan Agreement approximate fair value as the interest rates are based on prevailing market rates; these are considered Level 1 fair value measurements. As EQM's borrowings under its senior notes are not actively traded, their fair values are estimated using an income approach model that applies a discount rate based on prevailing market rates for debt with similar remaining time-to-maturity and credit risk; as such, their fair values are Level 2 fair value measurements. Effective on March 3, 2020, the ETRN Term Loans were paid off with proceeds from the Amended EQM Credit Facility (see Note 9), and the ETRN Term Loan Credit Agreement was terminated. As of December 31, 2019, the estimated fair value of the ETRN Term Loans was approximately $595 million and the carrying value of the ETRN Term Loans was approximately $568 million. As of September 30, 2020 and December 31, 2019, the estimated fair values of EQM's senior notes were approximately $5,139 million and $3,421 million, respectively, and the carrying values of EQM's senior notes were approximately $5,043 million and $3,462 million, respectively. The fair value of the Preferred Interest is a Level 3 fair value measurement and is estimated using an income approach model that applies a market-based discount rate. As of September 30, 2020 and December 31, 2019, the estimated fair values of the Preferred Interest were approximately $127 million and $126 million, respectively, and the carrying values of the Preferred Interest were approximately $106 million and $110 million, respectively.

Earnings (Loss) Per Share

Earnings (Loss) Per Share	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Earnings (Loss) Per Share	Earnings (Loss) Per ShareThe following tables set forth the computation of the basic and diluted earnings (loss) per share attributable to Equitrans Midstream common shareholders for the three and nine months ended September 30, 2020 and 2019: Three Months Ended September 30, 2020 2019 Basic Diluted Basic Diluted (In thousands, except per share data) Net income (loss) $ 168,439 $ 168,439 $ (61,489) $ (61,489) Less: Net income (loss) attributable to noncontrolling interests (excluding EQM Series A Preferred Units) 3,973 3,973 (44,144) (44,144) Less: EQM Series A Preferred Units interest in net income — — 48,480 48,480 Less: Preferred dividends 14,628 14,628 — — Net income (loss) attributable to Equitrans Midstream common shareholders $ 149,838 $ 149,838 $ (65,825) $ (65,825) Basic weighted average common shares outstanding 432,773 432,773 254,915 254,915 Dilutive securities (a)(b) — 48 — — Diluted weighted average common shares outstanding 432,773 432,821 254,915 254,915 Earnings (loss) per share of common stock attributable to Equitrans Midstream common shareholders $ 0.35 $ 0.35 $ (0.26) $ (0.26) Nine Months Ended September 30, 2020 2019 Basic Diluted Basic Diluted (In thousands, except per share data) Net income $ 501,457 $ 501,457 $ 268,557 $ 268,557 Less: Net income attributable to noncontrolling interests (excluding EQM Series A Preferred Units) 163,406 163,406 155,082 155,082 Less: EQM Series A Preferred Units interest in net income 47,359 47,359 48,480 48,480 Less: Preferred dividends 44,132 44,132 — — Net income attributable to Equitrans Midstream common shareholders $ 246,560 $ 246,560 $ 64,995 $ 64,995 Basic weighted average common shares outstanding 314,411 314,411 254,868 254,868 Dilutive securities (a)(b) — — — 19 Diluted weighted average common shares outstanding 314,411 314,411 254,868 254,887 Earnings per share of common stock attributable to Equitrans Midstream common shareholders $ 0.78 $ 0.78 $ 0.26 $ 0.25 (a) For the periods presented, as applicable, EQM's dilutive securities issued and outstanding prior to the EQM Merger did not have a material impact on the Company's diluted earnings per share. (b) For the three and nine months ended September 30, 2020, the Company excluded 30,099 and 11,995 (in thousands), respectively, of weighted average anti-dilutive securities related to the Equitrans Midstream Preferred Shares and stock-based compensation awards. For the three months ended September 30, 2019, the Company excluded 45 (in thousands) of weighted average anti-dilutive securities related to stock-based compensation awards. Preferred dividends include a $27.3 million premium recognized on the redemption of the EQM Series A Preferred Units as part of the Restructuring Closing during the nine months ended September 30, 2020.

Income Taxes

Income Taxes	9 Months Ended
	Sep. 30, 2020
Income Tax Disclosure [Abstract]
Income Taxes	Income TaxesThe Company's effective tax rate was 14.4% for the three months ended September 30, 2020, compared to (3.3)% for the three months ended September 30, 2019. The Company's effective tax rate was 14.0% for the nine months ended September 30, 2020, compared to 14.6% for the nine months ended September 30, 2019. The effective tax rate was higher for the three months ended September 30, 2020 compared to the three months ended September 30, 2019 primarily due to the tax impact of the impairments of long-lived assets (see Note 4) during the three months ended September 30, 2019 and, for the three months ended September 30, 2020, the decrease in net income attributable to noncontrolling interests as a result of the EQM Merger and related effect on the Company's estimated annual effective tax rate, partially offset by an increase in AFUDC - equity. Excluding other items, the effective tax rates for the three and nine months ended September 30, 2020 and 2019 were lower than the statutory rates because the Company does not record income tax expense on the portion of its income attributable to the noncontrolling member of Eureka Midstream and did not record income tax expense on the portion of its income attributable to the noncontrolling limited partners of EQM and EQGP for the periods prior to the closing of the EQM Merger and the EQGP Buyout, respectively.

Financial Statements (Policies)

Financial Statements (Policies)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Basis of Presentation	Basis of Presentation. References in these financial statements to Equitrans Midstream or the Company refer collectively to Equitrans Midstream Corporation and, as applicable, its consolidated subsidiaries for all periods presented, unless otherwise indicated. The accompanying unaudited consolidated financial statements have been prepared in accordance with GAAP for interim financial information and with the requirements of Form 10-Q and Article 10 of Regulation S-X. Accordingly, they do not include all of the information and footnotes required by GAAP for complete financial statements. In the opinion of management, these unaudited consolidated financial statements include all adjustments (consisting of only normal, recurring adjustments, unless otherwise disclosed in this Quarterly Report on Form 10-Q) necessary for a fair presentation of the financial position of the Company as of September 30, 2020 and December 31, 2019, the results of its operations and equity for the three and nine months ended September 30, 2020 and 2019 and its cash flows for the nine months ended September 30, 2020 and 2019. The consolidated balance sheet at December 31, 2019 has been derived from the audited financial statements at that date but does not include all of the information and notes required by GAAP for complete financial statements. This Quarterly Report on Form 10-Q should be read in conjunction with the Company's Annual Report on Form 10-K for the year ended December 31, 2019, which includes all disclosures required by GAAP. Due to, among other things, the seasonal nature of the Company's utility customer contracts and temporary volume curtailments by certain of the Company's customers, including EQT, as well as producers’ well completion activities and varying needs for fresh and produced water (which are partially driven by horizontal lateral lengths and the number of completion stages per well), the interim statements for the three and nine months ended September 30, 2020 are not necessarily indicative of the results that may be expected for the year ending December 31, 2020. For further information, refer to the Company's annual consolidated financial statements and related notes in the Company's Annual Report on Form 10-K for the year ended December 31, 2019, as well as "Management's Discussion and Analysis of Financial Condition and Results of Operations" contained herein.
Recently Issued Accounting Standards	Recently Issued Accounting Standards In June 2016, the FASB issued ASU 2016-13, Financial Instruments-Credit Losses (Topic 326): Measurement of Credit Losses on Financial Instruments. The standard amended guidance on reporting credit losses for assets held at amortized cost basis and available for sale debt securities. For assets held at amortized cost basis, this standard eliminated the probable initial recognition threshold in then current GAAP, and, in its place, requires an entity to recognize its current estimate of all expected credit losses. The amendments affected loans, debt securities, trade receivables, contract assets, net investments in leases, off balance sheet credit exposures, reinsurance receivables, and any other financial assets not excluded from the scope of the standard that have the contractual right to receive cash. In May 2019, the FASB issued ASU 2019-05, Financial Instruments – Credit Losses (Topic 326). The update provides entities with targeted transition relief that is intended to increase comparability of financial statement information for some entities that otherwise would have measured similar financial instruments using different measurement methodologies. In November 2019, the FASB issued ASU 2019-11, Codification Improvements to Topic 326, Financial Instruments – Credit Losses. The update clarifies and addresses stakeholders' specific issues in ASU 2016-13. The Company adopted the standard on January 1, 2020, using the modified retrospective method for all financial assets recorded at amortized cost. Results for reporting periods beginning after January 1, 2020 are presented under Topic 326 while prior period amounts continue to be reported in accordance with previously applicable GAAP. The Company's current expected credit loss (CECL) methodology considers risks of collection based on a customer’s current credit status. The standard requires an entity to assess whether financial assets share similar risk characteristics and, if so, group such assets in a pool. Customer balances are aggregated for evaluation based on their credit risk rating, which takes into account changes in economic factors that impact a customer’s ability to meet its financial obligations. The Company's CECL methodology assigns a reserve, even if remote, to each customer based on credit risk. The table below summarizes the changes in the allowance for credit losses by outstanding receivable for the nine months ended September 30, 2020: Accounts Receivable Contract Asset (a) Other Assets (b) Total Balance at December 31, 2019 $ (285) $ — $ — $ (285) Adoption of Topic 326 (2,708) — (1,010) (3,718) Provision for (recovery of) expected credit losses (616) (222) 26 (812) Balance at September 30, 2020 $ (3,609) $ (222) $ (984) $ (4,815) (a) Included in other current assets in the consolidated balance sheets. (b) Includes the Company's Preferred Interest in EES and other long-term receivables. In August 2018, the FASB issued ASU 2018-13, Fair Value Measurement, Changes to the Disclosure Requirements for Fair Value Measurement , which makes a number of changes to the hierarchy associated with Level 1, 2 and 3 fair value measurements and the related disclosure requirements. This guidance is effective for fiscal years beginning after December 15, 2019, including interim periods within those fiscal years. The Company adopted this standard on January 1, 2020. The adoption of this standard did not have an impact on the Company's financial statements. In December 2019, the FASB issued ASU 2019-12, Simplifying the Accounting for Income Taxes , which enhances and simplifies various aspects of the income tax accounting guidance including the elimination of certain exceptions related to the approach for intra-period tax allocation, the methodology for calculating income taxes in an interim period and the recognition of deferred tax liabilities for outside basis differences. The guidance also simplifies aspects of the accounting for franchise taxes and enacted changes in tax laws or rates and clarifies the accounting for transactions that result in a step-up in the tax basis of goodwill. The guidance will be effective for fiscal years, and interim periods within those fiscal years, beginning after December 15, 2020, with early adoption permitted. The Company early-adopted the standard in the first quarter of 2020 with no significant effect on its financial statements or related disclosures. In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848) , which provides practical expedients for contract modifications and certain hedging relationships associated with the transition from reference rates that are expected to be discontinued. This guidance is applicable for the Amended EQM Credit Facility, the Amended 2019 EQM Term Loan Agreement (as defined in Note 9) and the Eureka Credit Facility, as well as for each dividend following March 31, 2024 for the Equitrans Midstream Preferred Shares, which each use the London Inter-Bank Offered Rate (LIBOR) as a reference rate. The ASU is effective immediately but is only available through December 31, 2022. The Company is currently evaluating the potential impact of this standard on its financial statements. In August 2020, the FASB issued ASU 2020-06, Accounting for Convertible Instruments and Contracts in an Entity’s Own Equity , which simplifies the accounting for convertible debt and convertible preferred stock by removing the requirements to separately present certain conversion features in equity. In addition, the amendments in the ASU 2020-06 also simplify the guidance in ASC Subtopic 815-40, Derivatives and Hedging: Contracts in Entity’s Own Equity , by removing certain criteria that must be satisfied in order to classify a contract as equity. Finally, the amendments revise the guidance on calculating earnings per share, requiring use of the if-converted method for all convertible instruments and rescinding an entity’s ability to rebut the presumption of share settlement for instruments that may be settled in cash or other assets. The amendments will be effective for fiscal years beginning after December 15, 2021. Early adoption is permitted for fiscal years beginning after December 15, 2020. Adoption of the guidance must commence at the beginning of the annual fiscal year. The Company is currently evaluating the potential impact of this standard on its financial statements.

Financial Statements (Tables)

Financial Statements (Tables)	9 Months Ended
	Sep. 30, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
New Accounting Policy	The table below summarizes the changes in the allowance for credit losses by outstanding receivable for the nine months ended September 30, 2020: Accounts Receivable Contract Asset (a) Other Assets (b) Total Balance at December 31, 2019 $ (285) $ — $ — $ (285) Adoption of Topic 326 (2,708) — (1,010) (3,718) Provision for (recovery of) expected credit losses (616) (222) 26 (812) Balance at September 30, 2020 $ (3,609) $ (222) $ (984) $ (4,815) (a) Included in other current assets in the consolidated balance sheets. (b) Includes the Company's Preferred Interest in EES and other long-term receivables.

Mergers and Acquisitions (Table

Mergers and Acquisitions (Tables)	9 Months Ended
	Sep. 30, 2020
Business Combinations [Abstract]
Schedule of Preliminary Purchase Price Allocations	The following table summarizes the final purchase price and allocation of the fair value of the assets acquired and liabilities assumed in the Bolt-on Acquisition as of April 10, 2019 by the Company, as well as certain measurement period adjustments made subsequent to the Company's initial valuation. (in thousands) Preliminary Purchase Price Allocation (As initially reported) Measurement Period Adjustments (a) Purchase Price Allocation (As adjusted) Consideration given: Cash consideration (b) $ 861,250 $ (11,404) $ 849,846 Buyout of portion of Eureka Midstream Class B Units and incentive compensation 2,530 — 2,530 Total consideration 863,780 (11,404) 852,376 Fair value of liabilities assumed: Current liabilities 52,458 (9,857) 42,601 Long-term debt 300,825 — 300,825 Other long-term liabilities 10,203 — 10,203 Amount attributable to liabilities assumed 363,486 (9,857) 353,629 Fair value of assets acquired: Cash 15,145 — 15,145 Accounts receivable 16,817 — 16,817 Inventory 12,991 (26) 12,965 Other current assets 882 — 882 Net property, plant and equipment 1,222,284 (8,906) 1,213,378 Intangible assets (c) 317,000 (6,000) 311,000 Deferred tax asset 5,773 (5,268) 505 Other assets 14,567 — 14,567 Amount attributable to assets acquired 1,605,459 (20,200) 1,585,259 Noncontrolling interests (486,062) 7,602 (478,460) Goodwill as of April 10, 2019 $ 107,869 $ (8,663) $ 99,206 Impairment of goodwill (d) (99,206) Goodwill as of September 30, 2020 $ — (a) The Company recorded measurement period adjustments to its preliminary acquisition date fair values due to the refinement of its valuation models, assumptions and inputs. The measurement period adjustments were based upon information obtained about facts and circumstances that existed at the acquisition date that, if known, would have affected the measurement of the amounts recognized at that date. (b) The cash consideration for the Bolt-on Acquisition was adjusted by approximately $11.4 million related to working capital adjustments and the release of all escrowed indemnification funds to EQM. (c) After considering the refinements to the valuation models, the Company estimated the fair value of the customer-related intangible assets acquired as part of the Bolt-on Acquisition to be $311.0 million. As a result, the fair value of the customer-related intangible assets was decreased by $6.0 million on September 30, 2019 with a corresponding increase to goodwill. In addition, the change to the provisional amount resulted in a decrease in amortization expense and accumulated amortization of approximately $0.4 million. (d) During the third quarter of 2019, the Company identified impairment indicators that suggested the fair value of its goodwill was more likely than not below its carrying amount. As such, the Company performed an interim goodwill impairment assessment, which resulted in the Company recognizing impairment to goodwill of approximately $268.1 million, of which $99.2 million was associated with its Eureka/Hornet reporting unit, bringing the reporting unit's goodwill balance to zero. See Note 4 for further detail.

Financial Information by Busi_2

Financial Information by Business Segment (Tables)	9 Months Ended
	Sep. 30, 2020
Segment Reporting [Abstract]
Schedule of Revenue from External Customers and Operating Income and Reconciliation to Net Income	Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (Thousands) Revenues from customers: Gathering $ 232,651 $ 299,491 $ 764,229 $ 847,038 Transmission 93,329 87,299 288,869 289,926 Water 24,020 21,644 90,605 67,419 Total operating revenues $ 350,000 $ 408,434 $ 1,143,703 $ 1,204,383 Operating income (loss): Gathering (a) $ 129,186 $ (98,489) $ 400,647 $ 177,720 Transmission 63,460 59,690 201,714 207,684 Water 10,118 7,722 40,173 18,980 Headquarters (b) (2,255) (7,376) (24,646) (16,621) Total operating income (loss) $ 200,509 $ (38,453) $ 617,888 $ 387,763 Reconciliation of operating income (loss) to net income (loss): Equity income (c) $ 60,917 $ 44,448 $ 171,233 $ 112,293 Other income 21,864 70 39,006 2,637 Loss on early extinguishment of debt — — 24,864 — Net interest expense 86,411 65,606 219,960 188,268 Income tax expense 28,440 1,948 81,846 45,868 Net income (loss) $ 168,439 $ (61,489) $ 501,457 $ 268,557 (a) Impairments of long-lived assets of $298.7 million for the three months ended September 30, 2019 and $55.6 million and $378.8 million for the nine months ended September 30, 2020 and 2019, respectively, were included in Gathering operating income (loss). See Note 4 for further information. (b) Includes separation and other transaction costs and other unallocated corporate expenses. (c) Equity income is included in the Transmission segment.
Schedule of Segment Assets	September 30, 2020 December 31, 2019 (Thousands) Segment assets: Gathering $ 7,743,615 $ 7,572,911 Transmission (a) 4,279,330 3,903,707 Water 208,899 202,440 Total operating segments 12,231,844 11,679,058 Headquarters, including cash 398,836 362,651 Total assets $ 12,630,680 $ 12,041,709 (a) The equity investments in the MVP Joint Venture are included in the Transmission segment.
Schedule of Depreciation and Amortization and Expenditures for Segment Assets	Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (Thousands) Depreciation: Gathering $ 44,648 $ 38,943 $ 126,915 $ 104,502 Transmission 13,659 13,347 40,787 38,474 Water 8,105 6,907 22,720 19,801 Headquarters 360 263 849 3,953 Total $ 66,772 $ 59,460 $ 191,271 $ 166,730 Capital expenditures for segment assets: Gathering (a) $ 90,452 $ 271,860 $ 303,063 $ 686,178 Transmission (b) 6,721 16,296 32,983 46,287 Water 2,530 13,466 8,377 31,490 Headquarters 447 1,068 3,234 6,787 Total (c) $ 100,150 $ 302,690 $ 347,657 $ 770,742 (a) Includes approximately $13.5 million and $37.1 million of capital expenditures related to the noncontrolling interest in Eureka Midstream for the three and nine months ended September 30, 2020, respectively, and includes approximately $6.7 million and $17.6 million of capital expenditures related to the noncontrolling interest in Eureka Midstream for the three and nine months ended September 30, 2019, respectively. (b) Transmission capital expenditures do not include capital contributions made to the MVP Joint Venture for the MVP and MVP Southgate projects of $65.6 million and $211.7 million for the three months ended September 30, 2020 and 2019, respectively, and $144.3 million and $512.9 million for the nine months ended September 30, 2020 and 2019, respectively. (c) The Company accrues capital expenditures when the work has been completed but the associated bills have not yet been paid. Accrued capital expenditures are excluded from the statements of consolidated cash flows until they are paid. The net impact of non-cash capital expenditures, including the effect of accrued capital expenditures, assumed capital expenditures associated with the Bolt-on Acquisition, transfers from inventory as assets are assigned to a project and capitalized share-based compensation costs, was $8.3 million and $(15.3) million for the three months ended September 30, 2020 and 2019, respectively, and $29.9 million and $(0.8) million for the nine months ended September 30, 2020 and 2019, respectively.

Revenue from Contracts with C_2

Revenue from Contracts with Customers (Tables)	9 Months Ended
	Sep. 30, 2020
Revenue from Contract with Customer [Abstract]
Schedule of Disaggregated Revenue Information, By Segment	The tables below provide disaggregated revenue information by business segment. Three Months Ended September 30, 2020 Gathering Transmission Water Total (Thousands) Firm reservation fee revenues (a) $ 145,533 $ 84,612 $ 9,005 $ 239,150 Volumetric-based fee revenues 87,118 8,717 15,015 110,850 Total operating revenues $ 232,651 $ 93,329 $ 24,020 $ 350,000 Three Months Ended September 30, 2019 Gathering Transmission Water Total (Thousands) Firm reservation fee revenues $ 154,791 $ 81,990 $ 840 $ 237,621 Volumetric-based fee revenues 144,700 5,309 20,804 170,813 Total operating revenues $ 299,491 $ 87,299 $ 21,644 $ 408,434 Nine Months Ended September 30, 2020 Gathering Transmission Water Total (Thousands) Firm reservation fee revenues (a) $ 446,721 $ 267,973 $ 32,788 $ 747,482 Volumetric-based fee revenues 317,508 20,896 57,817 396,221 Total operating revenues $ 764,229 $ 288,869 $ 90,605 $ 1,143,703 Nine Months Ended September 30, 2019 Gathering Transmission Water Total (Thousands) Firm reservation fee revenues $ 431,520 $ 263,051 $ 4,531 $ 699,102 Volumetric-based fee revenues 415,518 26,875 62,888 505,281 Total operating revenues $ 847,038 $ 289,926 $ 67,419 $ 1,204,383 (a) For the three months ended September 30, 2020, firm reservation fee revenues associated with Gathering and Water included approximately $2.6 million and $1.9 million, respectively, of MVC unbilled revenues. For the nine months ended September 30, 2020, firm reservation fee revenues associated with Gathering and Water included approximately $13.7 million and $11.4 million, respectively, of MVC unbilled revenues. There were no MVC unbilled revenues associated with Gathering and Water during the three and nine months ended September 30, 2019.
Contract with Customer, Asset and Liability	The following table presents changes in the Company's unbilled revenue balance during the nine months ended September 30, 2020: Unbilled Revenue (Thousands) Balance as of January 1, 2020 $ — Revenue recognized in excess of amounts invoiced (a) 25,086 Minimum volume commitments invoiced (b) — Balance as of September 30, 2020 $ 25,086 (a) Revenues associated with unbilled MVCs are included in firm reservation fee revenues within the Gathering and Water segments, as described in the Summary of Disaggregated Revenues table above. (b) Unbilled revenues are transferred to accounts receivable once the Company has an unconditional right to consideration from the customer. The following table presents changes in the Company's deferred revenue balances during the nine months ended September 30, 2020: Deferred Revenue (Thousands) Balance as of January 1, 2020 $ — Amounts recorded during the period (a) 321,775 Amounts transferred during the period (b) — Balance as of September 30, 2020 $ 321,775 (a) Includes deferred billed revenue of approximately $74.6 million and $148.8 million recorded during the three and nine months ended September 30, 2020, respectively, associated with the EQT Global GGA. (b) Deferred revenues are recognized as revenue upon satisfaction of the Company's performance obligation to the customer.
Summary of Remaining Performance Obligations	The following table summarizes the estimated transaction price allocated to the Company's remaining performance obligations under all contracts with firm reservation fees and MVCs as of September 30, 2020 that the Company will invoice or transfer from contract liabilities and recognize in future periods. 2020 (a) 2021 2022 2023 2024 Thereafter Total (Thousands) Gathering firm reservation fees $ 22,081 $ 106,127 $ 158,721 $ 158,628 $ 157,127 $ 1,433,923 $ 2,036,607 Gathering revenues supported by MVCs 125,591 526,413 585,384 617,532 635,649 5,367,726 7,858,295 Transmission firm reservation fees 94,112 360,242 380,890 342,566 282,962 2,609,294 4,070,066 Water revenues supported by MVCs 9,006 16,521 60,000 60,000 60,000 105,000 310,527 Total (b) $ 250,790 $ 1,009,303 $ 1,184,995 $ 1,178,726 $ 1,135,738 $ 9,515,943 $ 14,275,495 (a) October 1, 2020 through December 31, 2020. (b) Includes assumptions regarding timing for placing certain projects, including the MVP, in-service. Delays in the in-service dates for projects may substantially alter the remaining performance obligations for certain contracts with firm reservation fees and/or MVCs.

Investments in Unconsolidated_2

Investments in Unconsolidated Entity (Tables)	9 Months Ended
	Sep. 30, 2020
Equity Method Investments and Joint Ventures [Abstract]
Schedule of Unaudited Condensed Financial Statements for the Investment in Unconsolidated Equity	The following tables summarize the unaudited condensed consolidated financial statements of the MVP Joint Venture in relation to the MVP project. Condensed Consolidated Balance Sheets September 30, 2020 December 31, 2019 (Thousands) Current assets $ 290,541 $ 102,638 Non-current assets 5,540,846 4,951,521 Total assets $ 5,831,387 $ 5,054,159 Current liabilities $ 187,826 $ 223,645 Equity 5,643,561 4,830,514 Total liabilities and equity $ 5,831,387 $ 5,054,159 Condensed Statements of Consolidated Operations Three Months Ended September 30, Nine Months Ended September 30, 2020 2019 2020 2019 (Thousands) Environmental remediation reserve $ 20 $ (516) $ (295) $ (2,682) Other income 13 1,165 275 5,863 Net interest income 39,280 29,100 110,868 73,035 AFUDC — equity 91,653 67,902 258,693 170,416 Net income $ 130,966 $ 97,651 $ 369,541 $ 246,632

Earnings (Loss) Per Share (Tabl

Earnings (Loss) Per Share (Tables)	9 Months Ended
	Sep. 30, 2020
Earnings Per Share [Abstract]
Schedule of Earnings Per Share, Basic and Diluted	The following tables set forth the computation of the basic and diluted earnings (loss) per share attributable to Equitrans Midstream common shareholders for the three and nine months ended September 30, 2020 and 2019: Three Months Ended September 30, 2020 2019 Basic Diluted Basic Diluted (In thousands, except per share data) Net income (loss) $ 168,439 $ 168,439 $ (61,489) $ (61,489) Less: Net income (loss) attributable to noncontrolling interests (excluding EQM Series A Preferred Units) 3,973 3,973 (44,144) (44,144) Less: EQM Series A Preferred Units interest in net income — — 48,480 48,480 Less: Preferred dividends 14,628 14,628 — — Net income (loss) attributable to Equitrans Midstream common shareholders $ 149,838 $ 149,838 $ (65,825) $ (65,825) Basic weighted average common shares outstanding 432,773 432,773 254,915 254,915 Dilutive securities (a)(b) — 48 — — Diluted weighted average common shares outstanding 432,773 432,821 254,915 254,915 Earnings (loss) per share of common stock attributable to Equitrans Midstream common shareholders $ 0.35 $ 0.35 $ (0.26) $ (0.26) Nine Months Ended September 30, 2020 2019 Basic Diluted Basic Diluted (In thousands, except per share data) Net income $ 501,457 $ 501,457 $ 268,557 $ 268,557 Less: Net income attributable to noncontrolling interests (excluding EQM Series A Preferred Units) 163,406 163,406 155,082 155,082 Less: EQM Series A Preferred Units interest in net income 47,359 47,359 48,480 48,480 Less: Preferred dividends 44,132 44,132 — — Net income attributable to Equitrans Midstream common shareholders $ 246,560 $ 246,560 $ 64,995 $ 64,995 Basic weighted average common shares outstanding 314,411 314,411 254,868 254,868 Dilutive securities (a)(b) — — — 19 Diluted weighted average common shares outstanding 314,411 314,411 254,868 254,887 Earnings per share of common stock attributable to Equitrans Midstream common shareholders $ 0.78 $ 0.78 $ 0.26 $ 0.25 (a) For the periods presented, as applicable, EQM's dilutive securities issued and outstanding prior to the EQM Merger did not have a material impact on the Company's diluted earnings per share. (b) For the three and nine months ended September 30, 2020, the Company excluded 30,099 and 11,995 (in thousands), respectively, of weighted average anti-dilutive securities related to the Equitrans Midstream Preferred Shares and stock-based compensation awards. For the three months ended September 30, 2019, the Company excluded 45 (in thousands) of weighted average anti-dilutive securities related to stock-based compensation awards.

Financial Statements (Details)

Financial Statements (Details)	Jun. 17, 2020USD ($)	Feb. 26, 2020USD ($)$ / shares	Nov. 12, 2018	Jun. 30, 2020USD ($)
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Percentage of cash distributions paid			80.10%
Redemptions				$ 661,874,000
Series A Preferred Units | EQM Merger
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Redemptions	$ 600,000,000	$ 600,000,000
Redemption percentage rate	1.01
Purchase price (in dollars per share) | $ / shares		$ 48.77
Preferred Stock | EQM Merger
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Redemption percentage rate	2.44
EQT Corporation and Subsidiaries | Equitrans Midstream
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Limited partner ownership interest			19.90%

Financial Statements - Impact o

Financial Statements - Impact of Adoption (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	$ (285)
Provision for (recovery of) expected credit losses	(812)
Balance at September 30, 2020	(4,815)
Cumulative Effect, Period of Adoption, Adjustment
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	(3,718)
Accounts Receivable
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	(285)
Provision for (recovery of) expected credit losses	(616)
Balance at September 30, 2020	(3,609)
Accounts Receivable | Cumulative Effect, Period of Adoption, Adjustment
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	(2,708)
Contract Asset
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	0
Provision for (recovery of) expected credit losses	(222)
Balance at September 30, 2020	(222)
Contract Asset | Cumulative Effect, Period of Adoption, Adjustment
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	0
Other Assets
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	0
Provision for (recovery of) expected credit losses	26
Balance at September 30, 2020	(984)
Other Assets | Cumulative Effect, Period of Adoption, Adjustment
Accounts Receivable, Allowance for Credit Loss [Roll Forward]
Balance at December 31, 2019	$ (1,010)

Investments in Consolidated, _2

Investments in Consolidated, Non-Wholly-Owed Entities (Details)

Aug. 13, 2020USD ($)

Jun. 17, 2020USD ($)

Feb. 26, 2020USD ($)day$ / sharesshares

Mar. 13, 2019

Feb. 13, 2019shares

Sep. 30, 2020USD ($)shares

Jun. 30, 2020USD ($)

Sep. 30, 2019USD ($)

Jun. 30, 2019USD ($)

Mar. 31, 2019USD ($)

Sep. 30, 2020USD ($)shares

Sep. 30, 2019USD ($)

Class of Stock

Aggregate change in common stock and noncontrolling interest

$ 1,627,000

$ (346,543,000)

Decrease in deferred tax asset

346,500,000

Redemptions

$ 661,874,000

Increase in deferred tax liability

$ 257,200,000

Transaction costs

984,000

$ 256,000

$ 23,797,000

$ 24,606,000

Conversion basis of common stock

100.00%

Convertible units

$ 20,000,000

Trading price threshold (per unit) | $ / shares

$ 27.99

Threshold trading days

20 days

Threshold amount of stock price trigger (in shares) | shares

1,000,000

Convertible common stock, consecutive trading days | day

20

Conversion price (in usd per share) | $ / shares

$ 19.99

Threshold percentage of consideration payable trigger, conversion ratio

110.00%

Increase in mezzanine equity

667,200,000

Change in deferred taxes

5,300,000

Minimum

Class of Stock

Threshold percentage of consideration payable trigger

90.00%

Threshold percentage of consideration payable trigger, redemption covenant

101.00%

Threshold percentage of consideration payable trigger, volume weighted average price covenant

95.00%

Series A Preferred Units | EQM Merger

Class of Stock

Redemption percentage rate

1.01

Redemptions

$ 600,000,000

$ 600,000,000

Cash paid to redeem EQM Series A preferred units

617,300,000

Partners' Capital

$ 590,100,000

Premium recognized on redemption

$ 27,300,000

Aggregate amount of distributions to be made to holder of Equitrans Midstream preferred shares

$ 10,900,000

Preferred Stock | EQM Merger

Class of Stock

Redemption percentage rate

2.44

EQM | Limited Partner Common

Class of Stock

Canceled common units (in shares) | shares

21,811,643

Common Stock

Class of Stock

Aggregate change in common stock and noncontrolling interest

82,700,000

$ 1,627,000

991,098,000

Redemptions

82,717,000

Common Stock | EQM Merger

Class of Stock

Aggregate change in common stock and noncontrolling interest

2,700,000,000

Noncontrolling Interests

Class of Stock

Aggregate change in common stock and noncontrolling interest

579,200,000

$ (1,337,641,000)

Redemptions

$ 579,157,000

Noncontrolling Interests | EQM Merger

Class of Stock

Aggregate change in common stock and noncontrolling interest

$ 3,000,000,000

EQM | Limited Partner Common

Class of Stock

Common units held (in shares) | shares

117,245,455

117,245,455

EQM | Common Class B | Limited Partner Common

Class of Stock

Common units held (in shares) | shares

7,000,000

7,000,000

EQM | EQGP | Limited Partner Common

Class of Stock

Partners' capital common units outstanding (in shares) | shares

21,811,643

EQM | Equitrans Gathering Holdings, LLC | Limited Partner Common

Class of Stock

Common units held (in shares) | shares

89,505,616

89,505,616

EQM | Equitrans Gathering Holdings, LLC | Common Class B | Limited Partner Common

Class of Stock

Common units held (in shares) | shares

6,153,907

6,153,907

EQM | EQM GP Corporation | Limited Partner Common

Class of Stock

Common units held (in shares) | shares

89,536

89,536

EQM | EQM GP Corporation | Common Class B | Limited Partner Common

Class of Stock

Common units held (in shares) | shares

6,155

6,155

EQM | Equitrans Midstream Holdings, LLC | Limited Partner Common

Class of Stock

Common units held (in shares) | shares

27,650,303

27,650,303

EQM | Equitrans Midstream Holdings, LLC | Common Class B | Limited Partner Common

Class of Stock

Common units held (in shares) | shares

839,938

839,938

EQM | Public Owned

Class of Stock

Limited partner ownership interest

40.10%

IDR Merger Agreement | EQM

Class of Stock

Common units received (in shares) | shares

80,000,000

IDR Merger Agreement | EQM | Common Class B

Class of Stock

Common units received (in shares) | shares

7,000,000

Private Placement

Class of Stock

Cumulative quarterly dividend rate

9.75%

Increase in quarterly distribution, percent

8.15%

Private Placement | Minimum

Class of Stock

Cumulative quarterly dividend rate

10.50%

Mergers and Acquisitions - Narr

Mergers and Acquisitions - Narrative (Details) $ in Thousands	Sep. 30, 2020USD ($)	Apr. 01, 2020USD ($)	Mar. 31, 2020	Apr. 10, 2019USD ($)mishares	Mar. 13, 2019USD ($)	Sep. 30, 2020USD ($)	Jun. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)
Business Acquisition
Shares issued to fund business acquisition (in shares) | shares				24,605,291
Interest, net of amount capitalized										$ 221,918	$ 223,257
Amortization of intangible assets						$ 16,204			$ 14,540	46,990	38,677
Hornet Midstream Holdings, LLC
Business Acquisition
Length of gathering lines (in miles) | mi				15
Intangible assets, useful life		7 years 3 months
Impairment of intangible assets								$ 17,700	36,400
Hornet Midstream Holdings, LLC | EQM
Business Acquisition
Limited partner ownership interest (as a percent)				100.00%
Bolt-on Acquisition
Business Acquisition
Cash consideration	$ 852,376			$ 863,780
Repayment of outstanding term loan credit					$ 28,200
Interest, net of amount capitalized					100
Acquisition related expenses									300		17,000
Professional fees									300		15,300
Compensation arrangements related to business acquisitions											1,700
Goodwill prior to impairment adjustment	99,206			99,200		99,206				99,206
Noncontrolling interest	478,460			486,062		478,460			478,500	478,460	478,500
Amortization of intangible assets							$ (400)
Impairment of intangible assets									$ 36,400		$ 36,400
Tax deductible goodwill				$ 43,000
Bolt-on Acquisition | EQM
Business Acquisition
Total consideration					1,040,000
Cash consideration					852,000
Assumed pro-rata debt					$ 192,000
Eureka Midstream Holdings, LLC
Business Acquisition
Length of gathering lines (in miles) | mi				190
Intangible assets, useful life		10 years 9 months	20 years
Amortization of intangible assets		$ 9,100
Intangible assets, amortization expense, 2020	5,800					5,800				5,800
Intangible assets, amortization expense, 2021	23,300					23,300				23,300
Intangible assets, amortization expense, 2022	23,300					23,300				23,300
Intangible assets, amortization expense, 2023	23,300					23,300				23,300
Intangible assets, amortization expense, 2024	23,300					23,300				23,300
Intangible assets, amortization expense, 2025	$ 23,300					$ 23,300				$ 23,300
Eureka Midstream Holdings, LLC | EQM
Business Acquisition
Limited partner ownership interest (as a percent)				60.00%

Mergers and Acquisitions - Sche

Mergers and Acquisitions - Schedule of Preliminary Purchase Price Allocation (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Apr. 10, 2019	Sep. 30, 2020	Jun. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019
Goodwill
Goodwill as of April 10, 2019					$ 486,698			$ 486,698
Impairment of goodwill					(268,100)
Goodwill as of September 30, 2020	$ 486,698		$ 486,698				$ 486,698	486,698
Decrease in amortization expense			(16,204)			$ (14,540)		(46,990)	$ (38,677)
Bolt-on Acquisition
Consideration given:
Cash consideration	849,846	$ 861,250
Buyout of portion of Eureka Midstream Class B Units and incentive compensation	2,530	2,530
Total consideration	852,376	863,780
Fair value of liabilities assumed:
Current liabilities	42,601	52,458	42,601				42,601	42,601
Long-term debt	300,825	300,825	300,825				300,825	300,825
Other long-term liabilities	10,203	10,203	10,203				10,203	10,203
Amount attributable to liabilities assumed	353,629	363,486	353,629				353,629	353,629
Fair value of assets acquired:
Cash	15,145	15,145	15,145				15,145	15,145
Accounts receivable	16,817	16,817	16,817				16,817	16,817
Inventory	12,965	12,991	12,965				12,965	12,965
Other current assets	882	882	882				882	882
Net property, plant and equipment	1,213,378	1,222,284	1,213,378				1,213,378	1,213,378
Intangible assets	311,000	317,000	311,000				311,000	311,000
Deferred tax asset	505	5,773	505				505	505
Other assets	14,567	14,567	14,567				14,567	14,567
Amount attributable to assets acquired	1,585,259	1,605,459	1,585,259				1,585,259	1,585,259
Noncontrolling interests	(478,460)	(486,062)	(478,460)			$ (478,500)	(478,460)	(478,460)	$ (478,500)
Measurement Period Adjustments
Total consideration				$ (11,400)			(11,404)
Current liabilities							(9,857)
Amount attributable to liabilities assumed							(9,857)
Inventory							(26)
Net property, plant and equipment							(8,906)
Intangible assets							(6,000)
Deferred tax asset							(5,268)
Amount attributable to assets acquired							(20,200)
Noncontrolling interests							7,602
Goodwill as of April 10, 2019							(8,663)
Goodwill
Goodwill prior to impairment adjustment	99,206	99,200	99,206				99,206	99,206
Goodwill as of April 10, 2019
Impairment of goodwill							(99,206)
Goodwill as of September 30, 2020	$ 0	$ 107,869	$ 0		$ 0		$ 0	$ 0
Decrease in amortization expense				$ 400

Impairments of Long-Lived Ass_2

Impairments of Long-Lived Assets and Other-Than-Temporary Decline in Value (Details) $ in Thousands		Feb. 26, 2020segmentreporting_unit	Feb. 25, 2020reporting_unitsegment	Aug. 31, 2019USD ($)	Sep. 30, 2020USD ($)	Mar. 31, 2020USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2020USD ($)segment	Sep. 30, 2019USD ($)
Property, Plant and Equipment
Number of operating segments | segment		3	3						3
Number of reporting units | reporting_unit		6	7
Impairment of goodwill						$ 268,100
Impairments of long-lived assets (Note 4)	[1]				$ 0		$ 305,459		$ 55,581	$ 385,594
Bolt-on Acquisition
Property, Plant and Equipment
Impairment of goodwill								$ 99,206
Impairment of intangible assets							$ 36,400			36,400
Eureka Midstream, LLC And Hornet Midstream, LLC Reporting Units
Property, Plant and Equipment
Impairment of goodwill				$ 99,200
RMP PA Gas Gathering Reporting Unit
Property, Plant and Equipment
Impairment of goodwill				$ 168,900
Gathering
Property, Plant and Equipment
Impairment of property and equipment									37,900
Impairment of intangible assets									$ 17,700
Impairments of long-lived assets (Note 4)										$ 80,100
[1]	See Note 4 for disclosure regarding impairments of long-lived assets.

Financial Information by Busi_3

Financial Information by Business Segment - Narrative (Details)	Feb. 26, 2020segment	Feb. 25, 2020segment	Sep. 30, 2020business_linesegment
Segment Reporting [Abstract]
Number of operating segments | segment	3	3	3
Number of lines of business | business_line			3

Financial Information by Busi_4

Financial Information by Business Segment - Schedule of Segment Income (Details) - USD ($) $ in Thousands		3 Months Ended					9 Months Ended
		Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Revenues from customers:
Operating revenues	[1]	$ 350,000		$ 408,434			$ 1,143,703	$ 1,204,383
Operating income (loss):
Total operating income (loss)		200,509		(38,453)			617,888	387,763
Reconciliation of operating income (loss) to net income (loss):
Equity income	[2]	60,917		44,448			171,233	112,293
Other income	[3]	21,864		70			39,006	2,637
Loss on early extinguishment of debt	[4]	0		0			24,864	0
Net interest expense	[1]	86,411		65,606			219,960	188,268
Income tax expense		28,440		1,948			81,846	45,868
Net income (loss)		168,439	$ 189,560	(61,489)	$ 130,480	$ 199,566	501,457	268,557
Impairment of long-lived assets	[5]	0		305,459			55,581	385,594
Gathering
Revenues from customers:
Operating revenues		232,651		299,491			764,229	847,038
Reconciliation of operating income (loss) to net income (loss):
Impairment of long-lived assets								80,100
Transmission
Revenues from customers:
Operating revenues		93,329		87,299			288,869	289,926
Water
Revenues from customers:
Operating revenues		24,020		21,644			90,605	67,419
Operating segments | Gathering
Revenues from customers:
Operating revenues		232,651		299,491			764,229	847,038
Operating income (loss):
Total operating income (loss)		129,186		(98,489)			400,647	177,720
Reconciliation of operating income (loss) to net income (loss):
Impairment of long-lived assets				298,700			55,600	378,800
Operating segments | Transmission
Revenues from customers:
Operating revenues		93,329		87,299			288,869	289,926
Operating income (loss):
Total operating income (loss)		63,460		59,690			201,714	207,684
Operating segments | Water
Revenues from customers:
Operating revenues		24,020		21,644			90,605	67,419
Operating income (loss):
Total operating income (loss)		10,118		7,722			40,173	18,980
Headquarters
Operating income (loss):
Total operating income (loss)		$ (2,255)		$ (7,376)			$ (24,646)	$ (16,621)
[1]	Includes related party activity with EQT. See Note 7.
[2]	Represents equity income from the MVP Joint Venture. See Note 8.
[3]	See Note 10 for disclosures regarding derivative instruments.
[4]	See Note 9 for disclosure regarding loss on early extinguishment of debt.
[5]	See Note 4 for disclosure regarding impairments of long-lived assets.

Financial Information by Busi_5

Financial Information by Business Segment - Assets (Details) - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Long-Lived Assets
Total assets	$ 12,630,680	$ 12,041,709
Operating segments
Long-Lived Assets
Total assets	12,231,844	11,679,058
Operating segments | Gathering
Long-Lived Assets
Total assets	7,743,615	7,572,911
Operating segments | Transmission
Long-Lived Assets
Total assets	4,279,330	3,903,707
Operating segments | Water
Long-Lived Assets
Total assets	208,899	202,440
Headquarters
Long-Lived Assets
Total assets	$ 398,836	$ 362,651

Financial Information by Busi_6

Financial Information by Business Segment - Depreciation and Capital Expenditures for Segment Assets (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Information
Depreciation	$ 66,772	$ 59,460	$ 191,271	$ 166,730
Capital expenditures for segment assets	100,150	302,690	347,657	770,742
Capitalized share-based compensation cost	8,300	(15,300)	29,900	(800)
Operating segments | Gathering
Segment Information
Depreciation	44,648	38,943	126,915	104,502
Capital expenditures for segment assets	90,452	271,860	303,063	686,178
Operating segments | Gathering | Eureka Midstream Holdings, LLC
Segment Information
Capital expenditures for segment assets	13,500	6,700	37,100	17,600
Operating segments | Transmission
Segment Information
Depreciation	13,659	13,347	40,787	38,474
Capital expenditures for segment assets	6,721	16,296	32,983	46,287
Operating segments | Transmission | MVP Southgate Project
Segment Information
Capital expenditures for segment assets	65,600	211,700	144,300	512,900
Operating segments | Water
Segment Information
Depreciation	8,105	6,907	22,720	19,801
Capital expenditures for segment assets	2,530	13,466	8,377	31,490
Headquarters
Segment Information
Depreciation	360	263	849	3,953
Capital expenditures for segment assets	$ 447	$ 1,068	$ 3,234	$ 6,787

Revenue from Contracts with C_3

Revenue from Contracts with Customers - Schedule of Disaggregated Revenue Information, by Business Segment (Details) - USD ($)		3 Months Ended		9 Months Ended
		Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue
Operating revenues	[1]	$ 350,000,000	$ 408,434,000	$ 1,143,703,000	$ 1,204,383,000
Firm reservation fee revenues
Disaggregation of Revenue
Operating revenues		239,150,000	237,621,000	747,482,000	699,102,000
Volumetric-based fee revenues
Disaggregation of Revenue
Operating revenues		110,850,000	170,813,000	396,221,000	505,281,000
Gathering
Disaggregation of Revenue
Operating revenues		232,651,000	299,491,000	764,229,000	847,038,000
Gathering | MVC
Disaggregation of Revenue
Operating revenues		2,600,000	0	13,700,000	0
Gathering | Firm reservation fee revenues
Disaggregation of Revenue
Operating revenues		145,533,000	154,791,000	446,721,000	431,520,000
Gathering | Volumetric-based fee revenues
Disaggregation of Revenue
Operating revenues		87,118,000	144,700,000	317,508,000	415,518,000
Transmission
Disaggregation of Revenue
Operating revenues		93,329,000	87,299,000	288,869,000	289,926,000
Transmission | Firm reservation fee revenues
Disaggregation of Revenue
Operating revenues		84,612,000	81,990,000	267,973,000	263,051,000
Transmission | Volumetric-based fee revenues
Disaggregation of Revenue
Operating revenues		8,717,000	5,309,000	20,896,000	26,875,000
Water
Disaggregation of Revenue
Operating revenues		24,020,000	21,644,000	90,605,000	67,419,000
Water | MVC
Disaggregation of Revenue
Operating revenues		1,900,000	0	11,400,000	0
Water | Firm reservation fee revenues
Disaggregation of Revenue
Operating revenues		9,005,000	840,000	32,788,000	4,531,000
Water | Volumetric-based fee revenues
Disaggregation of Revenue
Operating revenues		$ 15,015,000	$ 20,804,000	$ 57,817,000	$ 62,888,000
[1]	Includes related party activity with EQT. See Note 7.

Revenue from Contracts with C_4

Revenue from Contracts with Customers - Unbilled Revenue Rollforward (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2020USD ($)
Change in Contract with Customer, Asset
Balance as of January 1, 2020	$ 0
Revenue recognized in excess of amounts invoiced (a)	25,086
Minimum volume commitments invoiced	0
Balance as of September 30, 2020	$ 25,086

Revenue from Contracts with C_5

Revenue from Contracts with Customers - Deferred Revenue Rollforward (Details) - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Sep. 30, 2019
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Balance as of January 1, 2020		$ 0
Amounts recorded during the period		321,775
Amounts transferred during the period		0
Balance as of September 30, 2020	$ 321,775	321,775
Contract liability		121,483	$ 0
EQT Corporation and Subsidiaries
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Contract liability	$ 74,600	$ 148,800

Revenue from Contracts with C_6

Revenue from Contracts with Customers - Summary of Remaining Performance Obligations (Details) $ in Thousands	Sep. 30, 2020USD ($)
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 14,275,495
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	250,790
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	1,009,303
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	1,184,995
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	1,178,726
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	1,135,738
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	9,515,943
Transmission firm reservation fees
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	4,070,066
Transmission firm reservation fees | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 94,112
Remaining performance obligations, expected timing	3 months
Transmission firm reservation fees | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 360,242
Remaining performance obligations, expected timing	1 year
Transmission firm reservation fees | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 380,890
Remaining performance obligations, expected timing	1 year
Transmission firm reservation fees | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 342,566
Remaining performance obligations, expected timing	1 year
Transmission firm reservation fees | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 282,962
Remaining performance obligations, expected timing	1 year
Transmission firm reservation fees | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 2,609,294
Remaining performance obligations, expected timing
Water revenues supported by MVCs
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 310,527
Water revenues supported by MVCs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 9,006
Remaining performance obligations, expected timing	3 months
Water revenues supported by MVCs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 16,521
Remaining performance obligations, expected timing	1 year
Water revenues supported by MVCs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 60,000
Remaining performance obligations, expected timing	1 year
Water revenues supported by MVCs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 60,000
Remaining performance obligations, expected timing	1 year
Water revenues supported by MVCs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 60,000
Remaining performance obligations, expected timing	1 year
Water revenues supported by MVCs | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 105,000
Remaining performance obligations, expected timing
Gathering firm reservation fees | Gathering
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 2,036,607
Gathering firm reservation fees | Gathering | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 22,081
Remaining performance obligations, expected timing	3 months
Gathering firm reservation fees | Gathering | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 106,127
Remaining performance obligations, expected timing	1 year
Gathering firm reservation fees | Gathering | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 158,721
Remaining performance obligations, expected timing	1 year
Gathering firm reservation fees | Gathering | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 158,628
Remaining performance obligations, expected timing	1 year
Gathering firm reservation fees | Gathering | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 157,127
Remaining performance obligations, expected timing	1 year
Gathering firm reservation fees | Gathering | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 1,433,923
Remaining performance obligations, expected timing
Gathering revenues supported by MVCs | Gathering
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 7,858,295
Gathering revenues supported by MVCs | Gathering | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2020-10-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 125,591
Remaining performance obligations, expected timing	3 months
Gathering revenues supported by MVCs | Gathering | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2021-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 526,413
Remaining performance obligations, expected timing	1 year
Gathering revenues supported by MVCs | Gathering | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2022-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 585,384
Remaining performance obligations, expected timing	1 year
Gathering revenues supported by MVCs | Gathering | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2023-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 617,532
Remaining performance obligations, expected timing	1 year
Gathering revenues supported by MVCs | Gathering | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 635,649
Remaining performance obligations, expected timing	1 year
Gathering revenues supported by MVCs | Gathering | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction
Total	$ 5,367,726
Remaining performance obligations, expected timing

Revenue from Contracts with C_7

Revenue from Contracts with Customers - Narrative (Details) $ in Thousands	Mar. 05, 2020USD ($)shares	Feb. 26, 2020USD ($)agreementBcf	Mar. 31, 2020USD ($)	Mar. 31, 2019USD ($)	Sep. 30, 2020USD ($)	Dec. 31, 2019USD ($)
Disaggregation of Revenue
Estimated aggregate fee relief, year one		$ 270,000
Estimated aggregate fee relief, year two		230,000
Estimated aggregate fee relief, year three		35,000
Option to forgo fee relief, year one		145,000
Option to forgo fee relief, year two		90,000
Cash payment to be made in exchange for fee relief		196,000
Contract liability		$ 121,500			$ 321,775	$ 0
Number of shares purchased			$ 190,992	$ 238,455
Deferred tax liability					17,200
Henry Hub cash payment
Disaggregation of Revenue
Derivative instrument, at fair value					$ 89,200
EQM
Disaggregation of Revenue
Number of share purchase agreements | agreement		2
Common Stock, Cash Shares
Disaggregation of Revenue
Number of shares purchased (in shares) | shares	4,769,496
Common Stock, Rate Relief Shares And Cash Shares
Disaggregation of Revenue
Number of shares purchased (in shares) | shares	20,530,256
Share Purchase Agreement | Common Stock, Cash Shares
Disaggregation of Revenue
Number of shares purchased	$ 46,000
Affiliated Entity | Water Services Letter Agreement
Disaggregation of Revenue
Fees incurred for services		$ 60,000
EQT Corporation and Subsidiaries
Disaggregation of Revenue
Firm reservation capacity, per day | Bcf		3
Firm reservation capacity, step up per day | Bcf		4
Derivative instrument, at fair value		$ 51,500
EQT Corporation and Subsidiaries | Share Purchase Agreement
Disaggregation of Revenue
Number of shares purchased	7,000
EQT Corporation and Subsidiaries | Share Purchase Agreement | Common Stock, Rate Relief Shares And Cash Shares
Disaggregation of Revenue
Number of shares purchased	$ 196,000
Gathering
Disaggregation of Revenue
Weighted average remaining term					15 years
Transmission
Disaggregation of Revenue
Weighted average remaining term					14 years

Related Party Transactions (Det

Related Party Transactions (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019	Feb. 26, 2020	Dec. 31, 2019
Related Party Transaction
Shares owned (in shares)	432,470,000		432,470,000			254,745,000
Operating and maintenance expense		$ 2,400,000		$ 2,400,000
Selling, general and administrative expense		1,000,000		1,000,000
Accounts receivable	$ 194,300,000		$ 194,300,000			$ 175,200,000
Unbilled revenue	11,400,000		11,400,000
EQT Corporation and Subsidiaries
Related Party Transaction
Revenue from related party	222,700,000	275,400,000	741,200,000	843,900,000
Affiliated Entity
Related Party Transaction
Interest income	1,500,000	$ 1,600,000	4,600,000	$ 4,800,000
Interest receivable						110,100,000
Affiliated Entity | Other current assets
Related Party Transaction
Interest receivable	5,200,000		5,200,000			5,000,000
Affiliated Entity | Other assets
Related Party Transaction
Interest receivable	$ 101,100,000		$ 101,100,000			105,100,000
EQT Corporation and Subsidiaries | EQM | Affiliated Entity
Related Party Transaction
Maximum borrowing capacity					$ 250,000,000
EQT Corporation and Subsidiaries | Equitrans Midstream
Related Party Transaction
Shares owned (in shares)	25,296,026		25,296,026
Ownership interest	5.90%		5.90%
EQM | Affiliated Entity | Level 3 | Carrying Value
Related Party Transaction
Preferred interest	$ 106,300,000		$ 106,300,000			$ 110,000,000

Investments in Unconsolidated_3

Investments in Unconsolidated Entity - Narrative (Details) $ in Millions	Nov. 04, 2019USD ($)	Nov. 30, 2020USD ($)	Oct. 31, 2020USD ($)	Sep. 30, 2020USD ($)mi	Sep. 30, 2020USD ($)mi	Dec. 31, 2020	Nov. 03, 2020USD ($)	Mar. 31, 2020USD ($)	Dec. 31, 2019USD ($)	Apr. 30, 2018mi
Con Edison | Maximum
Schedule of Equity Method Investments
Investment cap	$ 530
MVP Joint Venture | Beneficial Owner
Schedule of Equity Method Investments
Percentage of ownership interest					66.67%
MVP Southgate Project
Schedule of Equity Method Investments
Letter of credit outstanding				$ 14.2	$ 14.2			$ 14.2
MVP Project
Schedule of Equity Method Investments
Letter of credit outstanding				220.2	220.2			$ 220.2
MVP Project | Subsequent Event
Schedule of Equity Method Investments
Letter of credit outstanding							$ 231.2
Variable Interest Entity, Not Primary Beneficiary | MVP Joint Venture
Schedule of Equity Method Investments
Payments to joint venture	$ 5,800				6,000
Maximum financial statement exposure				$ 2,829	$ 2,829
Variable Interest Entity, Not Primary Beneficiary | MVP Joint Venture | Scenario, Forecast
Schedule of Equity Method Investments
Maximum financial statement exposure							$ 2,967
Variable Interest Entity, Not Primary Beneficiary | MVP Joint Venture | EQM
Schedule of Equity Method Investments
Ownership interest				45.90%	45.90%
Variable Interest Entity, Not Primary Beneficiary | MVP Joint Venture | EQM | Scenario, Forecast
Schedule of Equity Method Investments
Ownership interest						47.60%
Variable Interest Entity, Not Primary Beneficiary | MVP Southgate Project
Schedule of Equity Method Investments
Ownership interest				47.20%	47.20%
Variable Interest Entity, Not Primary Beneficiary | MVP Southgate Project | Subsequent Event
Schedule of Equity Method Investments
Payments to joint venture			$ 0.7
Variable Interest Entity, Not Primary Beneficiary | MVP Project
Schedule of Equity Method Investments
Capital contribution payable to MVP Joint Venture				$ 126.6
Variable Interest Entity, Not Primary Beneficiary | MVP Project | Subsequent Event
Schedule of Equity Method Investments
Payments to joint venture			$ 14.4
Variable Interest Entity, Not Primary Beneficiary | MVP Project | Scenario, Forecast | Subsequent Event
Schedule of Equity Method Investments
Payments to joint venture		$ 112.2
Variable Interest Entity, Not Primary Beneficiary | MVP Holdco Project | Subsequent Event
Schedule of Equity Method Investments
Payments to joint venture		$ 0.3
MVP
Schedule of Equity Method Investments
Length of pipeline (in miles) | mi				300	300
MVP | Variable Interest Entity, Not Primary Beneficiary
Schedule of Equity Method Investments
Issuance of performance guarantee, remaining capital obligation, percentage									33.00%
Issuance of performance guarantee									$ 223
MVP Southgate Project
Schedule of Equity Method Investments
Length of pipeline (in miles) | mi										75
MVP Southgate Project | Variable Interest Entity, Not Primary Beneficiary
Schedule of Equity Method Investments
Issuance of performance guarantee									$ 14

Investments in Unconsolidated_4

Investments in Unconsolidated Entity - Balance Sheet for the Investment in Unconsolidated Equity (Details) - MVP Joint Venture - USD ($) $ in Thousands	Sep. 30, 2020	Dec. 31, 2019
Condensed Consolidated Balance Sheets
Current assets	$ 290,541	$ 102,638
Non-current assets	5,540,846	4,951,521
Total assets	5,831,387	5,054,159
Current liabilities	187,826	223,645
Equity	5,643,561	4,830,514
Total liabilities and equity	$ 5,831,387	$ 5,054,159

Investments in Unconsolidated_5

Investments in Unconsolidated Entity - Income Statement for the Investment in Unconsolidated Equity (Details) - MVP Joint Venture - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Condensed Statements of Consolidated Operations
Environmental remediation reserve	$ 20	$ (516)	$ (295)	$ (2,682)
Other income	13	1,165	275	5,863
Net interest income	39,280	29,100	110,868	73,035
AFUDC — equity	91,653	67,902	258,693	170,416
Net income	$ 130,966	$ 97,651	$ 369,541	$ 246,632

Debt - Equitrans Midstream Term

Debt - Equitrans Midstream Term Loan Facility (Details) - USD ($)		Mar. 03, 2020	Dec. 31, 2018	Mar. 03, 2020	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument
Current portion of revolving credit facility borrowings and long-term debt	[1]						$ 302,500,000	$ 6,000,000
Letters of credit outstanding	[2]						$ 485,000,000	902,500,000
Term Loans | Equitrans Midstream Term Loans
Debt Instrument
Principal			$ 600,000,000
Net proceeds from offering		$ 650,000,000	568,100,000
Discount			18,000,000
Debt issuance costs			$ 13,900,000
Write off of debt issuance cost		$ 24,400,000
Current portion of revolving credit facility borrowings and long-term debt								6,000,000
Long term line of credit								594,000,000
Letters of credit outstanding								$ 0
Weighted average annual interest rate				6.20%	6.80%	6.90%
[1]	Includes aggregate borrowings outstanding on the Eureka Credit Facility (as defined in Note 9) as of September 30, 2020. See Note 9 for further detail.
[2]	Includes aggregate borrowings outstanding on the Amended EQM Credit Facility (as defined in Note 9) as of September 30, 2020. As of December 31, 2019, the Company had aggregate borrowings outstanding of approximately $610 million and $293 million on the Amended EQM Credit Facility and the Eureka Credit Facility, respectively. The Company had no borrowings outstanding under the Equitrans Midstream Credit Facility as of December 31, 2019. See Note 9 for further detail.

Debt - Equitrans Midstream Cred

Debt - Equitrans Midstream Credit Facility (Details) - USD ($)		Mar. 03, 2020	Mar. 03, 2020	Sep. 30, 2019	Sep. 30, 2019	Sep. 30, 2020	Dec. 31, 2019	Oct. 31, 2018
Debt Instrument
Letters of credit outstanding	[1]					$ 485,000,000	$ 902,500,000
Equitrans Midstream Credit Facility | Line of credit
Debt Instrument
Maximum borrowing capacity								$ 100,000,000
Write off of debt issuance cost		$ 500,000
Long term line of credit							0
Maximum amount of short term loans outstanding					$ 44,000,000
Average daily balance of short term loans outstanding					$ 4,000,000
Weighted average annual interest rate					4.30%
Payment commitment fees			$ 100,000	$ 100,000	$ 300,000
Equitrans Midstream Credit Facility | Letter of credit
Debt Instrument
Letters of credit outstanding		$ 0	$ 0				$ 0
[1]	Includes aggregate borrowings outstanding on the Amended EQM Credit Facility (as defined in Note 9) as of September 30, 2020. As of December 31, 2019, the Company had aggregate borrowings outstanding of approximately $610 million and $293 million on the Amended EQM Credit Facility and the Eureka Credit Facility, respectively. The Company had no borrowings outstanding under the Equitrans Midstream Credit Facility as of December 31, 2019. See Note 9 for further detail.

Debt - Amended EQM Revolving Cr

Debt - Amended EQM Revolving Credit Facility and 2019 EQM Term Loan Agreement (Details)		Oct. 31, 2018USD ($)	Aug. 31, 2019USD ($)	Oct. 31, 2018USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Jun. 30, 2019USD ($)	Sep. 30, 2019USD ($)	Sep. 30, 2020USD ($)	Sep. 30, 2019USD ($)	Dec. 31, 2019USD ($)	Nov. 01, 2018USD ($)
Debt Instrument
Letters of credit outstanding	[1]				$ 485,000,000				$ 485,000,000		$ 902,500,000
EQM | EQM Credit Facility | Revolving Credit Facility
Debt Instrument
Borrowings outstanding					485,000,000				485,000,000		610,000,000
Letters of credit outstanding					$ 235,000,000				$ 235,000,000		1,000,000
Weighted average annual interest rate					2.60%	3.70%			2.90%	3.80%
EQM | Line of credit | EQM Credit Facility
Debt Instrument
Maximum borrowing capacity		$ 1,000,000,000		$ 1,000,000,000								$ 3,000,000,000
Additional available borrowings				$ 750,000,000
Maximum amount of short term loans outstanding					$ 485,000,000	$ 1,690,000,000			$ 2,040,000,000	$ 1,690,000,000
Average daily balance of short term loans outstanding					485,000,000	865,000,000			975,000,000	950,000,000
Commitment fees					$ 2,400,000	$ 1,200,000			$ 5,000,000	$ 3,300,000
EQM | Line of credit | EQM Credit Facility | Each Fiscal Quarter Ending on or after the Revolver Amendment Date and on or prior to Mar.31 2021
Debt Instrument
Debt Instrument, Covenant Compliance, Consolidated Leverage Ratio		5.75		5.75
EQM | Line of credit | EQM Credit Facility | Each Fiscal Quarter Ending on and After Mar. 31 2023
Debt Instrument
Debt Instrument, Covenant Compliance, Consolidated Leverage Ratio		5		5
EQM | Line of credit | EQM Credit Facility | Base Rate | Minimum
Debt Instrument
Basis spread on variable rate		0.125%
EQM | Line of credit | EQM Credit Facility | Base Rate | Maximum
Debt Instrument
Basis spread on variable rate		1.75%
EQM | Line of credit | EQM Credit Facility | Eurodollar | Minimum
Debt Instrument
Basis spread on variable rate		1.125%
EQM | Line of credit | EQM Credit Facility | Eurodollar | Maximum
Debt Instrument
Basis spread on variable rate		2.75%
EQM | Unsecured Debt | 2019 Term Loan Facility
Debt Instrument
Principal			$ 1,400,000,000
Weighted average annual interest rate					2.40%	3.60%			2.80%
Net proceeds from offering			1,397,400,000
Debt issuance costs			2,600,000
Long term line of credit					$ 1,400,000,000				$ 1,400,000,000		1,400,000,000
EQM | Unsecured Debt | 2019 EQM Term Loan Agreement
Debt Instrument
Principal			$ 300,000,000
EQM | Same-day swing line advances | EQM Credit Facility
Debt Instrument
Maximum borrowing capacity		$ 250,000,000		$ 250,000,000
EQM | Letter of credit | EQM Credit Facility
Debt Instrument
Maximum borrowing capacity		$ 400,000,000		400,000,000
Maximum amount of short term loans outstanding									0
EQM | Term Loans | EQM Credit Facility | Eurodollar | Minimum
Debt Instrument
Basis spread on variable rate		1.00%
EQM | Term Loans | EQM Credit Facility | Eurodollar | Maximum
Debt Instrument
Basis spread on variable rate		2.625%
EQM | Term Loans | 2019 EQM Term Loan Agreement | Base Rate | Minimum
Debt Instrument
Basis spread on variable rate		0.00%
EQM | Term Loans | 2019 EQM Term Loan Agreement | Base Rate | Maximum
Debt Instrument
Basis spread on variable rate		1.625%
Eureka Midstream, LLC | Eureka Credit Facility
Debt Instrument
Borrowings outstanding											$ 293,000,000
Eureka Midstream, LLC | Line of credit | Eureka Credit Facility
Debt Instrument
Maximum borrowing capacity		$ 400,000,000		$ 400,000,000
Additional available borrowings		$ 500,000,000
Maximum amount of short term loans outstanding							$ 293,000,000		323,000,000
Borrowings outstanding					303,000,000				303,000,000
Average daily balance of short term loans outstanding					$ 310,000,000	$ 293,000,000		$ 285,000,000	$ 300,000,000
Weighted average annual interest rate					2.40%	4.30%		4.30%	2.60%
[1]	Includes aggregate borrowings outstanding on the Amended EQM Credit Facility (as defined in Note 9) as of September 30, 2020. As of December 31, 2019, the Company had aggregate borrowings outstanding of approximately $610 million and $293 million on the Amended EQM Credit Facility and the Eureka Credit Facility, respectively. The Company had no borrowings outstanding under the Equitrans Midstream Credit Facility as of December 31, 2019. See Note 9 for further detail.

Debt - Eureka Credit Facility (

Debt - Eureka Credit Facility (Details) - Eureka Midstream, LLC - Eureka Credit Facility - USD ($)	Oct. 31, 2018	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Sep. 30, 2019	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument
Borrowings outstanding							$ 293,000,000
Line of credit
Debt Instrument
Maximum borrowing capacity	$ 400,000,000
Additional available borrowings	$ 500,000,000
Borrowings outstanding		$ 303,000,000				$ 303,000,000
Maximum amount of short term loans outstanding				$ 293,000,000		323,000,000
Average daily balance of short term loans outstanding		$ 310,000,000	$ 293,000,000		$ 285,000,000	$ 300,000,000
Weighted average annual interest rate		2.40%	4.30%		4.30%	2.60%
Payment commitment fees		$ 100,000	$ 100,000		$ 200,000	$ 400,000

Debt - 2020 Senior Notes (Detai

Debt - 2020 Senior Notes (Details) - EQM Senior notes	3 Months Ended
	Jun. 30, 2020USD ($)	Jun. 17, 2020
6.00% Senior Notes Due July 1, 2025
Debt Instrument
Principal	$ 700,000,000
Interest rate	6.00%
6.50% Senior Note Due July 1, 2027
Debt Instrument
Principal	$ 900,000,000
Interest rate	6.50%
2020 Senior Notes
Debt Instrument
Net proceeds from offering	$ 1,576,100,000
Discount	20,000,000
Debt issuance costs	$ 3,900,000
Redemption percentage rate		1.01

Fair Value Measurements (Detail

Fair Value Measurements (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Gain on derivative instrument	$ 21	$ 37.7
EQM | Fair Value | Level 3 | EES
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Preferred interest	127	127	$ 126
EQM | Carrying Value | Level 3 | EES
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Preferred interest	106.3	106.3	110
EQM Senior notes | EQM | Fair Value | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Long-term debt	5,139	5,139	3,421
EQM Senior notes | EQM | Carrying Value | Level 2 | Fair Value, Measurements, Recurring
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Long-term debt	5,043	5,043	3,462
Equitrans Midstream Term Loans | Term Loans | Fair Value | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Long-term debt			595
Equitrans Midstream Term Loans | Term Loans | Carrying Value | Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Long-term debt			$ 568
Henry Hub cash payment
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative instrument, at fair value	89.2	89.2
Henry Hub cash payment | Other current assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative instrument, at fair value	35.3	35.3
Henry Hub cash payment | Other assets
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis
Derivative instrument, at fair value	$ 53.9	$ 53.9

Earnings (Loss) Per Share (Deta

Earnings (Loss) Per Share (Details) - USD ($) $ / shares in Units, $ in Thousands		3 Months Ended					9 Months Ended
		Sep. 30, 2020	Mar. 31, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Class of Stock
Net income		$ 168,439	$ 189,560	$ (61,489)	$ 130,480	$ 199,566	$ 501,457	$ 268,557
Less: Net income (loss) attributable to noncontrolling interests (excluding EQM Series A Preferred Units)		3,973		4,336			210,765	203,562
Less: Preferred dividends	[1]	14,628		0			44,132	0
Net income (loss) attributable to Equitrans Midstream common shareholders		$ 149,838		$ (65,825)			$ 246,560	$ 64,995
Weighted average common shares outstanding - basic (in shares)		432,773,000		254,915,000			314,411,000	254,868,000
Dilutive securities (in shares)		48,000		0				19,000
Weighted average common stock outstanding - diluted (in shares)		432,821,000		254,915,000			314,411,000	254,887,000
Earnings (loss) per share of common stock attributable to Equitrans Midstream common shareholders - basic (in dollars per share)	[2]	$ 0.35		$ (0.26)			$ 0.78	$ 0.26
Earnings (loss) per share of common stock attributable to Equitrans Midstream common shareholders - diluted (in dollars per share)	[2]	$ 0.35		$ (0.26)			$ 0.78	$ 0.25
Potentially dilutive securities (in shares)		30,099,000		45,000			11,995,000
EQM Merger | Series A Preferred Units
Class of Stock
Premium recognized on redemption							$ 27,300
Series A Preferred Units
Class of Stock
Less: Net income (loss) attributable to noncontrolling interests (excluding EQM Series A Preferred Units)		$ 3,973		$ (44,144)			163,406	$ 155,082
Less: EQM Series A Preferred Units interest in net income		0		48,480			47,359	48,480
Equitrans Preferred Shares
Class of Stock
Less: Preferred dividends		$ 14,628		$ 0			$ 44,132	$ 0
[1]	See Notes 2 and 11
[2]	See Note 11 for disclosure regarding the Company's calculation of net income per share of common stock (basic and diluted).

Income Taxes (Details)

Income Taxes (Details)	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Tax Disclosure [Abstract]
Effective tax rate	14.40%	(3.30%)	14.00%	14.60%