Common Stock and Earnings Per Share (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Reserved, Authorized and Unissued Common Stock
Possible future acquisitions (in shares)	20,457								20,457
Stock compensation plans (in shares)	10,048								10,048
Total (in shares)	30,505								30,505
Basic earnings per common share:
Net income attributable to EQT Corporation	$ 48,041	$ 31,873	$ 31,446	$ 72,035	$ 90,846	$ 178,914	$ 87,754	$ 122,255	$ 183,395	$ 479,769	$ 227,700
Average common shares outstanding									149,619	149,392	144,458
Net income (in dollars per share)	$ 0.32	$ 0.21	$ 0.21	$ 0.48	$ 0.61	$ 1.20	$ 0.59	$ 0.82	$ 1.23	$ 3.21	$ 1.58
Diluted earnings per common share:
Net income attributable to EQT Corporation	$ 48,041	$ 31,873	$ 31,446	$ 72,035	$ 90,846	$ 178,914	$ 87,754	$ 122,255	$ 183,395	$ 479,769	$ 227,700
Average common shares outstanding									149,619	149,392	144,458
Potentially dilutive securities:
Stock options and awards (in shares)									887	817	774
Total (in shares)									150,506	150,209	145,232
Net income (in dollars per share)	$ 0.32	$ 0.21	$ 0.21	$ 0.48	$ 0.60	$ 1.19	$ 0.58	$ 0.82	$ 1.22	$ 3.19	$ 1.57
Options to purchase common stock not included in potentially dilutive securities (in shares)									281,528	6,480	1,229,109