STATEMENTS OF CONSOLIDATED CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Cash flows from operating activities:
Net loss	$ (967,176)	$ (1,221,695)	$ (2,007,158)
Adjustments to reconcile net loss to net cash provided by operating activities:
Deferred income tax expense (benefit)	(155,840)	(275,063)	(510,405)
Depreciation and depletion	1,393,465	1,538,745	1,729,739
Amortization of intangible assets	26,006	35,916	77,374
Impairment/loss on sale/exchange of long-lived assets and leases	442,111	1,710,122	2,989,684
Gain on Equitrans Share Exchange	(187,223)	0	0
Impairment of goodwill	0	0	798,689
Loss on investment in Equitrans Midstream Corporation	314,468	336,993	72,366
Loss on debt extinguishment	25,435	0	0
Share-based compensation expense	19,552	31,233	25,189
Amortization, accretion and other	37,414	23,296	(33,039)
(Gain) loss on derivatives not designated as hedges	(400,214)	(616,634)	178,591
Cash settlements received (paid) on derivatives not designated as hedges	897,190	246,639	(225,279)
Net premiums (paid) received on derivative instruments	(46,665)	22,616	0
Changes in other assets and liabilities:
Accounts receivable	(36,296)	432,323	(439,062)
Accounts payable	(29,193)	(238,674)	457,113
Income tax receivable and payable	322,763	(167,281)	(117,188)
Other current assets	(68,628)	54,776	(28,256)
Other items, net	(49,468)	(61,608)	7,898
Net cash provided by operating activities	1,537,701	1,851,704	2,976,256
Cash flows from investing activities:
Capital expenditures	(1,042,231)	(1,602,454)	(2,999,037)
Cash paid for acquisitions (see Note 6)	(691,942)	0	0
Capital expenditures for discontinued operations	0	0	(732,727)
Capital contributions to Mountain Valley Pipeline, LLC	0	0	(820,943)
Proceeds from sale of assets	126,080	0	583,381
Cash received for Equitrans Share Exchange	52,323	0	0
Other investing activities	(30)	1,312	(9,778)
Net cash used in investing activities	(1,555,800)	(1,601,142)	(3,979,104)
Cash flows from financing activities:
Net proceeds from issuance of common stock	340,923	0	0
Proceeds from borrowings on credit facility	3,118,250	2,978,750	8,637,500
Repayment of borrowings on credit facility	(3,112,250)	(3,484,750)	(8,953,500)
Proceeds from issuance of debt	2,600,000	1,000,000	2,500,000
Debt issuance costs and Capped Call Transactions (See Note 10)	(71,056)	(913)	(40,966)
Repayments and retirements of debt	(2,822,262)	(704,661)	(8,376)
Premiums paid on debt extinguishment	(21,132)	0	0
Dividends paid	(7,664)	(30,655)	(31,375)
Proceeds and excess tax benefits from awards under employee compensation plans	0	0	1,946
Cash paid for taxes related to net settlement of share-based incentive awards	(596)	(7,224)	(22,647)
Repurchase and retirement of common stock	0	0	(538,876)
Repurchase of common stock	0	0	(27)
Contributions from (distributions to) noncontrolling interests	7,500
Contributions from (distributions to) noncontrolling interests		0	(380,651)
Acquisition of 25% of Strike Force Midstream LLC	0	0	(175,000)
Net cash transferred at Separation and Distribution	0	0	(129,008)
Net cash provided by (used in) financing activities	31,713	(249,453)	859,020
Net change in cash and cash equivalents	13,614	1,109	(143,828)
Cash and cash equivalents at beginning of year	4,596	3,487	147,315
Cash and cash equivalents at end of year	$ 18,210	$ 4,596	$ 3,487