Financial Information by Business Segment - Schedule of Operating Revenue by Segment (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Segment Reporting Information [Line Items]
Sales of natural gas, oil and NGLs									$ 1,594,997	$ 1,690,360	$ 2,132,409
Pipeline and net marketing services									262,342	263,640	256,359
(Loss) gain on derivatives not designated as hedges									(248,991)	385,762	80,942
Total operating revenues	$ 379,022	$ 556,726	$ 127,531	$ 545,069	$ 601,380	$ 583,978	$ 439,589	$ 714,815	1,608,348	2,339,762	2,469,710
Operating Segments | EQT Production
Segment Reporting Information [Line Items]
Sales of natural gas, oil and NGLs									1,594,997	1,690,360	2,132,409
Pipeline and net marketing services									41,048	55,542	71,787
(Loss) gain on derivatives not designated as hedges									(248,991)	385,762	80,942
Total operating revenues									1,387,054	2,131,664	2,285,138
Operating Segments | EQT Gathering
Segment Reporting Information [Line Items]
Sales of natural gas, oil and NGLs									0	0	0
Pipeline and net marketing services									397,494	335,105	233,945
(Loss) gain on derivatives not designated as hedges									0	0	0
Total operating revenues									397,494	335,105	233,945
Operating Segments | EQT Transmission and Storage
Segment Reporting Information [Line Items]
Sales of natural gas, oil and NGLs									0	0	0
Pipeline and net marketing services									338,120	297,831	255,273
(Loss) gain on derivatives not designated as hedges									0	0	0
Total operating revenues									338,120	297,831	255,273
Intersegment Eliminations
Segment Reporting Information [Line Items]
Sales of natural gas, oil and NGLs									0	0	0
Pipeline and net marketing services									(514,320)	(424,838)	(304,646)
(Loss) gain on derivatives not designated as hedges									0	0	0
Total operating revenues									$ (514,320)	$ (424,838)	$ (304,646)