Financial Information by Business Segment - Schedule of Depreciation, Amortization, and Expenditures (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Depreciation, depletion and amortization:
Depreciation, depletion and amortization	$ 437,893	$ 231,918
Expenditures for segment assets:
Expenditures for segment assets	764,982	1,017,313
Payments to acquire businesses, gross	0	669,479
Operating Segments | EQT Production
Depreciation, depletion and amortization:
Depreciation, depletion and amortization	400,058	211,097
Expenditures for segment assets:
Expenditures for segment assets	675,028	945,458
Payments to acquire businesses, gross		669,500
Capital expenditures incurred but not yet paid		15,400
Operating Segments | EQT Production | Fill-ins and Bolt-ons
Expenditures for segment assets:
Expenditures for segment assets	36,800	42,700
Operating Segments | EQT Production | Retained Assets
Expenditures for segment assets:
Expenditures for segment assets	44,300
Operating Segments | EQM Gathering
Depreciation, depletion and amortization:
Depreciation, depletion and amortization	10,738	8,860
Expenditures for segment assets:
Expenditures for segment assets	68,933	48,838
Operating Segments | EQM Transmission
Depreciation, depletion and amortization:
Depreciation, depletion and amortization	12,441	11,687
Expenditures for segment assets:
Expenditures for segment assets	18,929	21,389
Operating Segments | RMP Gathering
Depreciation, depletion and amortization:
Depreciation, depletion and amortization	8,124	0
Expenditures for segment assets:
Expenditures for segment assets	20,940	0
Operating Segments | RMP Water
Depreciation, depletion and amortization:
Depreciation, depletion and amortization	5,771	0
Expenditures for segment assets:
Expenditures for segment assets	2,375	0
Other
Depreciation, depletion and amortization:
Depreciation, depletion and amortization	761	274
Expenditures for segment assets:
Expenditures for segment assets	$ (21,223)	$ 1,628