Separation and Distribution and Discontinued Operations - Schedule of Cash Provided by Discontinued Operations (Details) - USD ($) $ in Thousands	10 Months Ended	12 Months Ended
	Nov. 12, 2018	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Operating activities:
Goodwill impairment		$ 798,689	$ 0	$ 0
Share-based compensation expense		$ 18,250	15,595	18,631
Midstream Business | Spinoff
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal Group, Including Discontinued Operation, Increase (Decrease) in Deferred Income Taxes	$ (373,405)		43,471	(21,936)
Operating activities:
Depreciation	160,701		106,574	71,469
Amortization of intangible assets	36,007		5,540	0
Asset impairments	0		0	59,748
Goodwill impairment	267,878		0	0
Other income	(51,450)		(27,281)	(29,300)
Share-based compensation expense	1,841		468	373
Investing activities:
Capital expenditures	(732,727)		(380,151)	(584,819)
Capital contributions to Mountain Valley Pipeline, LLC (a)	(820,943)		(159,550)	(98,399)
Sales of interests in Mountain Valley Pipeline, LLC (a)	0		0	12,533
Financing activities:
Net proceeds from the issuance of common units of EQM	0		0	217,102
Proceeds from issuance of debt	2,500,000		0	500,018
Increase in borrowings on credit facilities	3,378,500		544,084	740,000
Repayment of borrowings on credit facilities	(3,219,500)		(344,000)	(1,039,000)
Distributions to noncontrolling interests	(380,651)		(236,123)	(189,981)
Contribution to Strike Force Midstream LLC by minority owner, net of distribution	0		6,738	0
Acquisition of 25% of Strike Force Midstream LLC	(175,000)		0	0
Debt issuance costs and revolving credit facility origination fees	$ (40,966)		$ (2,257)	$ (8,580)