Financial Information by Business Segment - Schedule of Depreciation, Amortization, and Expenditures (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Depreciation and depletion:
Depreciation and depletion	$ 435,311	$ 246,560	$ 1,290,876	$ 719,295
Expenditures for segment assets:
Expenditures for segment assets	1,105,862	522,299	2,809,518	2,081,986
Payments to acquire businesses, gross			0	818,957
Operating Segments | EQT Production
Depreciation and depletion:
Depreciation and depletion	391,083	224,103	1,161,718	654,411
Expenditures for segment assets:
Expenditures for segment assets	855,494	449,303	2,225,435	1,850,482
Accrual (reversal) of capital expenditures	(51,800)	44,300	(45,200)	102,700
Payments to acquire businesses, gross		7,800		819,000
Capital expenditures incurred but not yet paid				7,500
Operating Segments | EQM Gathering
Depreciation and depletion:
Depreciation and depletion	25,359	9,983	72,309	28,398
Expenditures for segment assets:
Expenditures for segment assets	194,477	48,182	515,072	150,728
Operating Segments | EQM Transmission
Depreciation and depletion:
Depreciation and depletion	12,357	12,261	37,228	35,793
Expenditures for segment assets:
Expenditures for segment assets	37,626	22,312	84,517	73,679
Operating Segments | EQM Water
Depreciation and depletion:
Depreciation and depletion	5,851	0	17,420	0
Expenditures for segment assets:
Expenditures for segment assets	7,981	0	17,358	0
Other
Depreciation and depletion:
Depreciation and depletion	661	213	2,201	693
Expenditures for segment assets:
Expenditures for segment assets	$ 10,284	$ 2,502	$ (32,864)	$ 7,097