EQT Midstream Partners, LP (Details)				3 Months Ended	6 Months Ended		12 Months Ended
	Jul. 28, 2016 USD ($) shares	Jul. 26, 2016 $ / shares	Mar. 30, 2015 USD ($)	Jun. 30, 2016 USD ($) mi $ / shares shares	Jun. 30, 2016 USD ($) Bcf / d mi	Jun. 30, 2015 USD ($)	Dec. 31, 2015 USD ($)
Subsidiary or equity method investee
Net proceeds					$ 217,102,000	$ 696,582,000
Increase to deferred tax liability				$ 15,000,000
Common Stock
Subsidiary or equity method investee
Increase (decrease) in ownership of EQT Midstream Partners LP				24,900,000
Noncontrolling Interest
Subsidiary or equity method investee
Increase (decrease) in ownership of EQT Midstream Partners LP				$ (39,900,000)
Mountain Valley Pipeline
Subsidiary or equity method investee
Natural gas interstate pipeline (in miles) | mi				300	300
EQM
Subsidiary or equity method investee
Common units issued (in shares) | shares				2,949,309
Average price per unit (in dollars per share) | $ / shares				$ 74.42
Net proceeds				$ 217,100,000
Commissions				2,200,000
Underwriters discount and offering expenses				$ 200,000
EQM | Subsequent Event
Subsidiary or equity method investee
Cash distribution declared	$ 40,800,000
EQM | Subsequent Event | General Partner
Subsidiary or equity method investee
Cash distribution declared (in dollars per share) | $ / shares		$ 0.78
Common unit, outstanding (in shares) | shares	80,581,758
Cash distribution declared	$ 1,600,000
Cash distribution declared related to IDRs	22,200,000
EQM | Subsequent Event | Limited Partner
Subsidiary or equity method investee
Cash distribution declared	$ 17,000,000
EQM | Maximum
Subsidiary or equity method investee
Aggregate offering price							$ 750,000,000
MVP Joint Venture
Subsidiary or equity method investee
Total consideration			$ 54,200,000
Percentage of capital contributions			100.00%
Firms capacity commitments per day (in bcf per day) | Bcf / d					2.0
Duration of firm capacity commitments					20 years
MVP Joint Venture | EQM | Variable Interest Entity, Not Primary Beneficiary
Subsidiary or equity method investee
Ownership percentage				45.50%	45.50%
MVP Joint Venture | EQT
Subsidiary or equity method investee
Firms capacity commitments per day (in bcf per day) | Bcf / d					1.29
MVP Holdco
Subsidiary or equity method investee
Percentage of membership interest			100.00%