Summary of Significant Accounting Policies - Narrative (Details)			12 Months Ended
	Oct. 12, 2016 segment	May 15, 2015 shares	Dec. 31, 2016 USD ($) $ / Mcfe certificate_of_deposit segment shares	Dec. 31, 2015 USD ($) $ / Mcfe dry_hole	Dec. 31, 2014 USD ($) $ / Mcfe	Dec. 31, 2013 USD ($)
Accounting Policies [Abstract]
Number of segments | segment	2		3
Maturity period (in months)			3 months
Number of CDs in denominations greater than $0.1 million held | certificate_of_deposit			2
Trading securities			$ 286,396,000	$ 0
Unrealized holding gain (loss)			1,500,000
Restricted cash			$ 75,000,000
Property acquisition term (in days)			180 days
Losses for lower of cost or market adjustments			$ 0	0	$ 3,200,000
Internal costs			115,400,000	114,400,000	108,500,000
Interest costs capitalized			$ 19,200,000	$ 35,800,000	$ 35,000,000
Overall average rate of depletion | $ / Mcfe			1.06	1.18	1.22
Forward price curve period (in years)			5 years
Property, Plant and Equipment [Line Items]
Cash and cash equivalents			$ 1,103,540,000	$ 1,601,232,000	$ 1,077,429,000	$ 845,641,000
Unproved property impairments			6,900,000	19,700,000	86,600,000
Unproved oil and gas property impairments primarily as a result of lease expirations prior to drilling			8,700,000	37,400,000	14,600,000
Unproved properties			1,698,826,000	898,270,000	824,527,000
Capitalized exploratory well costs			5,100,000.0	$ 0	9,000,000
Number of exploratory dry holes | dry_hole				1
Impairment of long lived assets			66,687,000	$ 122,469,000	267,339,000
Property, plant and equipment, net			13,162,216,000	11,472,021,000
Regulatory assets associated with deferred taxes			20,300,000	73,100,000
AFUDC interest costs capitalized			2,400,000	1,600,000	1,000,000
AFUDC equity amounts capitalized			$ 19,400,000	6,300,000	3,200,000
Largest amount of benefit threshold, percentage (no greater than)			50.00%
Limited Partner Common
Property, Plant and Equipment [Line Items]
Limited partner interest (as a percent)		90.10%
Number of common units retained (in shares) | shares		239,715,000
Limited Partner Common | EQGP
Property, Plant and Equipment [Line Items]
Shares issued in IPO (in shares) | shares		26,450,000
Limited partner interest (as a percent)		9.90%
Limited Partner Common | EQGP | Affiliated Entity
Property, Plant and Equipment [Line Items]
Limited partner interest (as a percent)			26.60%
Common units owned (in shares) | shares			21,811,643
General Partner | EQGP
Property, Plant and Equipment [Line Items]
General partner interest (as a percent)			1.80%
General Partner | EQGP | Affiliated Entity
Property, Plant and Equipment [Line Items]
Number of general partner units (in shares) | shares			1,443,015
Minimum
Property, Plant and Equipment [Line Items]
Ownership percentage			20.00%
Maximum
Property, Plant and Equipment [Line Items]
Ownership percentage			50.00%
EQT Midstream | Building
Property, Plant and Equipment [Line Items]
Estimated service life (in years)			35 years
EQT Midstream | Vehicles
Property, Plant and Equipment [Line Items]
Estimated service life (in years)			5 years
EQT Midstream | Minimum | Gathering and Transmission Systems
Property, Plant and Equipment [Line Items]
Estimated service life (in years)			20 years
EQT Midstream | Minimum | Office Equipment
Property, Plant and Equipment [Line Items]
Estimated service life (in years)			3 years
EQT Midstream | Minimum | Computer Equipment
Property, Plant and Equipment [Line Items]
Estimated service life (in years)			3 years
EQT Midstream | Maximum | Gathering and Transmission Systems
Property, Plant and Equipment [Line Items]
Estimated service life (in years)			65 years
EQT Midstream | Maximum | Office Equipment
Property, Plant and Equipment [Line Items]
Estimated service life (in years)			7 years
EQT Midstream | Maximum | Computer Equipment
Property, Plant and Equipment [Line Items]
Estimated service life (in years)			7 years
EQT Production
Property, Plant and Equipment [Line Items]
Impairment of long lived assets			$ 6,939,000	122,469,000	267,339,000
Asset and lease impairments and exploratory well costs				4,200,000	0
Permian Basin of Texas
Property, Plant and Equipment [Line Items]
Pretax impairment charges on proved oil and gas properties				94,300,000	105,200,000
Fair value				44,800,000	109,200,000
Carrying value of properties				345,000,000
Carrying value of undeveloped properties				300,000,000
Utica
Property, Plant and Equipment [Line Items]
Pretax impairment charges on proved oil and gas properties				4,300,000	75,500,000
Fair value				5,700,000	7,400,000
Impairment of Oil and Gas Properties
Property, Plant and Equipment [Line Items]
Pretax impairment charges on proved oil and gas properties				$ 98,600,000	$ 180,700,000
Certificates of Deposit
Property, Plant and Equipment [Line Items]
Cash and cash equivalents			300,000,000
Unallocated Expenses
Property, Plant and Equipment [Line Items]
Impairment of long lived assets			$ 59,700,000