Summary of Significant Accounting Policies (Details) (EQT Midstream Partners, LP)	0 Months Ended	12 Months Ended
Jul. 22, 2013	Jul. 02, 2012	Dec. 31, 2013 General partner	Dec. 31, 2013 Limited partner
Principles of Consolidation
Ownership percentage	44.60%	59.40%	2.00%	42.60%

Percentage of subsidiary's or equity method investee's stock owned by parent immediately after all stock transactions.

No definition available.

Name:	us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration