Commitments and Contingencies Additional Information (Details) (USD $)				9 Months Ended	3 Months Ended				9 Months Ended			12 Months Ended	3 Months Ended			3 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 Subsidiaries	Sep. 30, 2013 South Carolina Electric Gas Company [Member]	Sep. 30, 2012 South Carolina Electric Gas Company [Member] Counterclaim [Member]	Sep. 30, 2012 South Carolina Electric Gas Company [Member] Award Amount [Member]	Sep. 30, 2012 South Carolina Electric Gas Company [Member] Interest Rate on Amount Awarded [Member]	Sep. 30, 2012 South Carolina Electric Gas Company [Member] Attorney Fees [Member]	Sep. 30, 2013 PCB Soil Removal Action	Sep. 30, 2012 PCB Soil Removal Action	Sep. 30, 2013 American electric corp [Member]	Dec. 31, 2012 American electric corp [Member]	Dec. 31, 2007 Earl Kennedy	Sep. 30, 2013 Cnx Gas Stock Acquisition [Member]	Dec. 31, 2012 Cnx Gas Stock Acquisition [Member]	Sep. 30, 2013 Ratliff [Member]
Commitments and Contingencies Disclosure [Line Items]
Loss Contingency, Range of Possible Loss, Portion Not Accrued	$ 792,000,000
Claims by plaintiff				36000									The complaint, as amended, seeks injunctive relief, including removing CNX Gas Company from the property, and compensatory damages of $20,000.			$4,000 to $8,000
The current estimated cost of remedial action for the area CONSOL Energy was originally named a PRP, including payment of the EPA's past and future cost, is approximately									65,000,000		5,400,000			19,200
Litigation Settlement, Gross												250,000
Counterclaim by the company					9400	9735	8.75	1232			408
Sale of Stock, Price Per Share															$ 38.25
Loss Contingency, Settlement Agreement, Court														42730
Loss Contingency, Estimate of Possible Loss									12,800,000
Cost of Remediation									1,000
Amount Funded to Remidiation Trust appearing in Cost of Goods Sold									2,563,000	400,000
Loss Contingency, Range of Possible Loss, Minimum											2,000,000
CONSOL Energy's portion of probable recoveries from settled claims									3,805,000
Remaining liability in PCB soil removal action	868,904,000	768,494,000							1,769,000
Loss Contingency, Damages Sought, Value											$ 384,000
Commitments and Contingent, number of asbestos claims			6,900