Share-Based Compensation Plans (Details 2) (USD $)	12 Months Ended			12 Months Ended			12 Months Ended				12 Months Ended								0 Months Ended	1 Months Ended	12 Months Ended
	Dec. 31, 2013 2012 Executive Performance Incentive Plan	Dec. 31, 2012 2012 Executive Performance Incentive Plan	Jan. 02, 2013 2012 Executive Performance Incentive Plan	Dec. 31, 2012 2010 Stock Incentive Award program	Jan. 02, 2013 2011 EQT Value Driver Award Program	Dec. 31, 2012 2011 EQT Value Driver Award Program	Dec. 31, 2012 2012 EQT Value Driver Award Program	Dec. 31, 2013 2012 EQT Value Driver Award Program	Jan. 31, 2013 2012 EQT Value Driver Award Program	Jan. 02, 2013 2012 EQT Value Driver Award Program	Dec. 31, 2013 2011 Volume and Efficiency Program	Dec. 31, 2013 Restricted Stock Awards	Dec. 31, 2012 Restricted Stock Awards	Dec. 31, 2011 Restricted Stock Awards	Dec. 31, 2013 Restricted Stock Awards Discontinued operations	Dec. 31, 2013 Non-employee Directors' Share-Based Awards	Dec. 31, 2012 Non-employee Directors' Share-Based Awards	Dec. 31, 2011 Non-employee Directors' Share-Based Awards	Jul. 02, 2012 Performance awards	Jul. 31, 2012 Performance awards	Dec. 31, 2013 Performance awards	Dec. 31, 2013 Phantom units	Dec. 31, 2012 Phantom units	Dec. 31, 2013 2013 EQT Value Driver Award Program	Dec. 31, 2013 2013 Executive Performance Incentive Plan	Dec. 31, 2013 Non-Qualified Stock Options	Dec. 31, 2012 Non-Qualified Stock Options	Dec. 31, 2011 Non-Qualified Stock Options	Dec. 31, 2013 2014 Value Driver Award Programs	Dec. 31, 2013 2014 Stock Options	Dec. 31, 2013 2014 Executive Performance Incentive Program	Dec. 31, 2013 2014 EQM Value Driver program	Dec. 31, 2012 Minimum 2012 Executive Performance Incentive Plan	Dec. 31, 2013 Minimum Performance awards	Dec. 31, 2013 Minimum 2013 Executive Performance Incentive Plan	Dec. 31, 2013 Minimum 2014 Value Driver Award Programs	Dec. 31, 2013 Minimum 2014 Executive Performance Incentive Program	Dec. 31, 2013 Minimum 2014 EQM Value Driver program	Dec. 31, 2012 Maximum 2012 Executive Performance Incentive Plan	Dec. 31, 2013 Maximum Performance awards	Dec. 31, 2013 Maximum 2013 Executive Performance Incentive Plan	Dec. 31, 2013 Maximum 2014 Value Driver Award Programs	Dec. 31, 2013 Maximum 2014 Executive Performance Incentive Program	Dec. 31, 2013 Maximum 2014 EQM Value Driver program
Share-Based Compensation Plans
Period after which the shares granted will be fully vested												3 years	3 years	3 years																3 years	3 years
Unrecognized compensation costs on non-vested awards	$ 13,800,000											$ 7,000,000									$ 1,700,000			$ 9,000,000	$ 23,200,000	$ 2,100,000
Non-employee Directors' share-based awards outstanding			351,480													179,639
Non-employee Directors' share-based awards granted																25,500	28,140	22,140
Non-employee Directors' weighted average fair value of shares, Granted (in dollars per share)																$ 58.98	$ 53.47	$ 44.84
Non-Vested Shares
Shares Outstanding, Beginning of Period					228,640			196,609	204,679	409,357		204,118
Number of shares granted		351,480										101,510	103,730	65,390					146,490	146,490	142,500	3,790	4,780		314,280				187,160		278,430	32,840
Percentage of unitholder return realized on common units from the date of grant																																		10.00%
Non-vested shares, Vested				(294,925)								(91,478)			(23,053)
Non-vested shares, Forfeited	(16,425)										(7,500)	(31,772)			(18,357)						(3,990)				(16,683)
Shares Outstanding, End of Period	335,055				228,640			196,609	204,679	409,357	221,140	182,378	204,118								146,490	8,886		614,048	297,597
Aggregate Fair Value
Weighted Average Fair Value, Beginning of Period (in dollars per share)												$ 49.86
Weighted Average Fair Value of shares, Granted (in dollars per share)	$ 123.37						$ 54.79				$ 48.06	$ 70.59	$ 54	$ 52							$ 20.02	$ 37.92	$ 24.30	$ 58.98	$ 126.45
Weighted Average Fair Value of shares, Vested (in dollars per share)												$ 46.87			$ 56.28
Weighted Average Fair Value of shares, Forfeited (in dollars per share)												$ 55.15			$ 55.00
Weighted Average Fair Value, End of Period (in dollars per share)												$ 61.98	$ 49.86
Restricted Stock, Aggregate Fair Value
Aggregate Fair Value, Beginning of Period												10,176,930
Aggregate Fair Value of shares, Granted												7,166,006
Aggregate Fair Value of shares, Vested				(12,600,000)								(4,287,701)	(1,600,000)	(5,100,000)	(1,300,000)
Aggregate Fair Value of shares, Forfeited												(1,752,243)			(1,000,000)
Aggregate Fair Value, End of Period												11,302,992	10,176,930
Assumptions used in the Black-Scholes single option pricing model
Risk-free interest rate (as a percent)		0.36%																							0.36%	0.76%	0.89%	2.02%
Dividend yield (as a percent)																										0.22%	1.64%	2.19%
Volatility factor (as a percent)																					38.00%					31.69%	31.44%	28.92%						27.00%						72.00%
Expected term		3 years																							3 years	5 years	5 years	5 years
Grants in period (in shares)																										259,600	278,300	229,100		133,500
Non-Qualified Stock Options, weighted average grant date fair value (in dollars per share)																										$ 16.72	$ 13.19	$ 10.06
Non-Qualified Stock Options, total intrinsic value of options exercised																										22,800,000	11,800,000	18,300,000
Non-qualified Stock Options, Shares
Non-qualified Stock Options Outstanding, Beginning of Period (in shares)																										1,864,375
Non-qualified Stock Options, Granted (in shares)																										259,600	278,300	229,100		133,500
Non-qualified Stock Options, Exercised (in shares)															(8,100)											(637,174)
Non-qualified Stock Options, Forfeited (in shares)																										(4,800)
Non-qualified Stock Options Outstanding, End of Period (in shares)																										1,482,001	1,864,375
Non-qualified Stock Options Exercisable, End of Period (in shares)																										1,088,051
Non-qualified Stock Options, Weighted Average Exercise Price
Weighted Average Exercise Price, Beginning of Period (in dollars per share)																										$ 46.01
Weighted Average Exercise Price of shares, Granted (in dollars per share)																										$ 58.98
Weighted Average Exercise Price of shares, Exercised (in dollars per share)															$ 24.39											$ 42.44
Weighted Average Exercise Price of shares, Forfeited (in dollars per share)																										$ 58.98
Weighted Average Exercise Price, End of Period (in dollars per share)																										$ 49.77	$ 46.01
Weighted Average Exercise Price of shares, Exercisable (in dollars per share)																										$ 46.98
Non-Qualified Stock Options, Weighted Average Remaining Contractual Term
Weighted Average Remaining Contractual Term, End of Period																										4 years 8 months 12 days				10 years
Weighted Average Remaining Contractual Term, Exercisable																										3 years 3 months 18 days
Non-qualified Stock Options, Aggregate Intrinsic Value
Aggregate Intrinsic Value Outstanding, End of Period																										59,287,589
Aggregate Intrinsic Value Exercisable, End of Period																										$ 46,570,891
Unrecognized compensation costs on non-vested awards, weighted average period of recognition												1 year 8 months 12 days									2 years				2 years
Award vested at end of year one, percentage						50.00%	50.00%																	50.00%					50.00%			50.00%
Award vested at end of year two, percentage						50.00%	50.00%																	50.00%					50.00%			50.00%
Compensation plan, award as a percentage of target award level											300.00%																						0.00%		0.00%	0.00%	0.00%	0.00%	300.00%		300.00%	300.00%	300.00%	300.00%
2013 Stock Options
Term of stock options																										4 years 8 months 12 days				10 years
Exercise price of stock options (in dollars per share)																														$ 89.78