Consolidated Statements of Stockholders' Equity (USD $)	Total	Common Stock [Member]	Capital in Excess of Par Value	Retained Earnings (Deficit)	Accumulated Other Comprehensive Income (Loss)	Common Stock in Treasury	Total CONSOL Energy Inc. Stockholders' Equity	Non-Controlling Interest
Balance, Beginning of Period at Dec. 31, 2008	$ 1,674,346,000	$ 1,830,000	$ 993,478,000	$ 1,010,902,000	$ (461,900,000)	$ (82,123,000)	$ 1,462,187,000	$ 212,159,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	567,142,000	0	0	539,717,000	0	0	539,717,000	27,425,000
Treasury Rate Lock	(83,000)	0	0	0	(83,000)	0	(83,000)	0
Gas Cash Flow Hedge	53,132,000	0	0	0	44,270,000	0	44,270,000	8,862,000
Actuarially Determined Long-Term Liability Adjustments (Net of $1,583 Tax)	(134,549,000)	0	0	0	(134,251,000)	0	(134,251,000)	(298,000)
Comprehensive Income (Loss)	379,378,000	0	0	539,717,000	(178,604,000)	0	361,113,000	18,265,000
Issuance of Treasury Stock	(5,598,000)	0	0	(21,429,000)	0	15,831,000	(5,598,000)	0
Proceeds from Issuance of Common Stock	0
Noncontrolling Interest, Increase from Equity Issuance or Sale of Parent Equity Interest	157,000	0	0	0	0	0	0	157,000
Tax Benefit from Stock-Based Compensation	2,687,000	0	2,674,000	0	0	0	2,674,000	13,000
Amortization of Stock-Based Compensation Awards	49,381,000	0	32,723,000	0	0	0	32,723,000	16,658,000
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	790,000	0	4,741,000	0	0	0	4,741,000	(3,951,000)
Net Change in Crown Drilling Noncontrolling Interest	(4,370,000)	0	0	0	0	0	0	(4,370,000)
Dividends	72,292,000	0	0	(72,292,000)	0	0	(72,292,000)	0
Balance, End of Period at Dec. 31, 2009	2,024,479,000	1,830,000	1,033,616,000	1,456,898,000	(640,504,000)	(66,292,000)	1,785,548,000	238,931,000
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	358,626,000	0	0	346,781,000	0	0	346,781,000	11,845,000
Treasury Rate Lock	(84,000)	0	0	0	(84,000)	0	(84,000)	0
Gas Cash Flow Hedge	25,291,000	0	0	0	30,543,000	0	30,543,000	(5,252,000)
Actuarially Determined Long-Term Liability Adjustments (Net of $1,583 Tax)	(221,228,000)	0	0	0	(221,233,000)	0	(221,233,000)	5,000
Comprehensive Income (Loss)	130,049,000	0	0	346,781,000	(233,834,000)	0	112,947,000	17,102,000
Issuance of Treasury Stock	(13,588,000)	0	0	(37,221,000)	0	23,633,000	(13,588,000)	0
Proceeds from Issuance of Common Stock	1,828,862,000	443,000	1,828,419,000	0	0	0	1,828,862,000	0
Noncontrolling Interest, Increase from Equity Issuance or Sale of Parent Equity Interest	2,178,000	0	0	0	0	0	0	2,178,000
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests	(1,009,060,000)	0	(746,052,000)	0	0	0	(746,052,000)	(263,008,000)
Other Comprehensive Income, Other, Net of Tax	18,026,000	0	0	0	18,026,000	0	18,026,000	0
Tax Benefit from Stock-Based Compensation	15,100,000	0	15,100,000	0	0	0	15,100,000	0
Amortization of Stock-Based Compensation Awards	47,593,000	0	45,395,000	0	0	0	45,395,000	2,198,000
Stock Issued During Period, Value, Share-based Compensation, Net of Forfeitures	355,000	0	2,126,000	0	0	0	2,126,000	(1,771,000)
Net Change in Crown Drilling Noncontrolling Interest	(4,094,000)	0	0	0	0	0	0	(4,094,000)
Dividends	85,861,000	0	0	85,861,000	0	0	85,861,000	0
Balance, End of Period at Dec. 31, 2010	2,936,013,000	2,273,000	2,178,604,000	1,680,597,000	(874,338,000)	(42,659,000)	2,944,477,000	(8,464,000)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Net Income (Loss)	632,497,000	0	0	632,497,000	0	0	632,497,000	0
Treasury Rate Lock	(96,000)	0	0	0	(96,000)	0	(96,000)	0
Gas Cash Flow Hedge	(105,693,000)	0	0	0	(105,693,000)	0	(105,693,000)	0
Actuarially Determined Long-Term Liability Adjustments (Net of $1,583 Tax)	(32,813,000)	0	0	0	(32,813,000)	0	(32,813,000)	0
Comprehensive Income (Loss)	705,281,000	0	0	632,497,000	72,784,000	0	705,281,000	0
Issuance of Treasury Stock	1,312,000	0	0	(32,001,000)	0	33,313,000	1,312,000	0
Proceeds from Issuance of Common Stock	0
Tax Benefit from Stock-Based Compensation	7,329,000	0	7,329,000	0	0	0	7,329,000	0
Amortization of Stock-Based Compensation Awards	48,842,000	0	48,842,000	0	0	0	48,842,000	0
Net Change in Crown Drilling Noncontrolling Interest	8,464,000	0	0	0	0	0	0	8,464,000
Dividends	96,356,000	0	0	96,356,000	0	0	96,356,000	0
Balance, End of Period at Dec. 31, 2011	$ 3,610,885,000	$ 2,273,000	$ 2,234,775,000	$ 2,184,737,000	$ (801,554,000)	$ (9,346,000)	$ 3,610,885,000	$ 0