Financial Information by Business Segment - Schedule of Operating Income and Reconciliation of Operating Income to Income from Continuing Operations (Details) - USD ($)		3 Months Ended								12 Months Ended
	Nov. 03, 2017	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating income (loss):
Total operating income (loss)		$ 214,849,000	$ 137,694,000	$ 189,794,000	$ 390,644,000	$ (189,466,000)	$ 108,457,000	$ (324,492,000)	$ 127,201,000	$ 932,981,000	$ (278,300,000)	$ 563,139,000
Reconciliation of operating income (loss) to net income (loss):
Other income										24,955,000	31,693,000	9,953,000
Loss on debt extinguishment	$ 12,600,000									12,641,000	0	0
Interest expense										202,772,000	147,920,000	146,531,000
Income tax (benefit) expense										(1,115,619,000)	(263,464,000)	104,675,000
Net income (loss)										1,858,142,000	(131,063,000)	321,886,000
Gain on sale / exchange of assets										0	8,025,000	0
Impairment of long-lived assets										0	66,687,000	122,469,000
Merger related expenses										237,312,000	0	0
Asset impairment charges										0		4,200,000
EQT Production
Reconciliation of operating income (loss) to net income (loss):
Gain on sale / exchange of assets											8,000,000
Impairment of long-lived assets										0	6,939,000	122,469,000
Operating Segments | EQT Production
Operating income (loss):
Total operating income (loss)										589,716,000	(719,731,000)	132,008,000
Operating Segments | EQM Gathering
Operating income (loss):
Total operating income (loss)										333,563,000	289,027,000	243,257,000
Operating Segments | EQM Transmission and Storage
Operating income (loss):
Total operating income (loss)										247,145,000	237,922,000	207,779,000
Operating Segments | RMP Gathering
Operating income (loss):
Total operating income (loss)										21,800,000	0	0
Operating Segments | RMP Water
Operating income (loss):
Total operating income (loss)										4,145,000	0	0
Unallocated Expenses
Operating income (loss):
Total operating income (loss)										(263,388,000)	(85,518,000)	$ (19,905,000)
Reconciliation of operating income (loss) to net income (loss):
Merger related expenses										$ 237,300,000
Asset impairment charges											$ 59,700,000