Financial Information by Business Segment - Schedule of Segment Assets (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Segment assets:
Assets	$ 29,522,604	$ 15,472,922	$ 13,976,172
Operating Segments
Segment assets:
Assets	28,491,976	13,548,711	12,093,865
Operating Segments | EQT Production
Segment assets:
Assets	22,711,854	10,923,824	9,905,344
Operating Segments | EQM Gathering
Segment assets:
Assets	1,411,857	1,225,686	1,019,004
Operating Segments | EQM Transmission and Storage
Segment assets:
Assets	1,462,881	1,399,201	1,169,517
Operating Segments | RMP Gathering
Segment assets:
Assets	2,720,305	0	0
Operating Segments | RMP Water
Segment assets:
Assets	185,079	0	0
Headquarters Assets, Including Cash and Short-Term Investments
Segment assets:
Assets	$ 1,030,628	$ 1,924,211	$ 1,882,307