Financial Information by Business Segment - Schedule of Depreciation, Amortization, and Expenditures (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Depreciation and depletion:
Depreciation and depletion	$ 417,672	$ 240,817	$ 855,565	$ 472,735
Expenditures for segment assets:
Expenditures for segment assets	938,715	542,374	1,703,692	1,559,687
Payments to acquire businesses, gross			0	811,207
Operating Segments | EQT Production
Depreciation and depletion:
Depreciation and depletion	374,782	219,211	770,635	430,308
Expenditures for segment assets:
Expenditures for segment assets	739,183	455,721	1,369,941	1,401,179
Accrual (reversal) of capital expenditures	(34,300)	37,400	6,600	58,400
Payments to acquire businesses, gross		141,700		811,200
Capital expenditures incurred but not yet paid				9,700
Operating Segments | EQT Production | Fill-ins and Bolt-ons
Expenditures for segment assets:
Expenditures for segment assets	41,300	47,000	78,100	89,700
Operating Segments | EQM Gathering
Depreciation and depletion:
Depreciation and depletion	15,646	9,555	30,590	18,415
Expenditures for segment assets:
Expenditures for segment assets	139,099	53,708	252,297	102,546
Operating Segments | EQM Transmission
Depreciation and depletion:
Depreciation and depletion	12,430	11,845	24,871	23,532
Expenditures for segment assets:
Expenditures for segment assets	27,962	29,978	46,891	51,367
Operating Segments | RMP Gathering
Depreciation and depletion:
Depreciation and depletion	8,236	0	16,360	0
Expenditures for segment assets:
Expenditures for segment assets	47,358	0	68,298	0
Operating Segments | RMP Water
Depreciation and depletion:
Depreciation and depletion	5,798	0	11,569	0
Expenditures for segment assets:
Expenditures for segment assets	7,002	0	9,377	0
Other
Depreciation and depletion:
Depreciation and depletion	780	206	1,540	480
Expenditures for segment assets:
Expenditures for segment assets	$ (21,889)	$ 2,967	$ (43,112)	$ 4,595