Reconciliation of Segment Information, Revenue and Other Income (Details) (USD $)	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Segment Reporting, Revenue Reconciling Item [Line Items]
Total Revenue and Other Income	$ 3,726,804,000us-gaap_Revenues	$ 3,299,685,000us-gaap_Revenues	$ 3,677,526,000us-gaap_Revenues
Revenue From External Customers	3,476,100,000cnx_RevenueFromExternalCustomers	3,120,722,000cnx_RevenueFromExternalCustomers	3,282,350,000cnx_RevenueFromExternalCustomers
Earnings Before Income Taxes:
Earnings Before Income Taxes	183,124,000	46,075,000	406,687,000
Other Income	207,103,000us-gaap_OtherIncome	111,483,000us-gaap_OtherIncome	113,170,000us-gaap_OtherIncome
Gain (Loss) on Disposition of Assets	43,601,000us-gaap_GainLossOnDispositionOfAssets1	67,480,000us-gaap_GainLossOnDispositionOfAssets1	282,006,000us-gaap_GainLossOnDispositionOfAssets1
Total Reportable Business Segments
Earnings Before Income Taxes:
Earnings Before Income Taxes	597,161,000	342,779,000	648,016,000
Coal Segment [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total Revenue and Other Income	2,121,569,000	2,096,869,000	2,327,750,000
Earnings Before Income Taxes:
Earnings Before Income Taxes	407,447,000	344,393,000	608,565,000
Gas
Segment Reporting, Revenue Reconciling Item [Line Items]
Total Revenue and Other Income	1,122,002,000	810,602,000	713,163,000
Earnings Before Income Taxes:
Earnings Before Income Taxes	189,714,000	(1,614,000)	39,451,000
Other Segments [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total Revenue and Other Income	313,216,000	343,972,000	385,073,000
Earnings Before Income Taxes:
Earnings Before Income Taxes	(32,821,000)	(17,201,000)	26,194,000
Excludes Gas Segment [Member]
Earnings Before Income Taxes:
Interest Income (Expense), Net and Other Non-operating Activity	(223,564,000)	(219,198,000)	(220,042,000)
Fees for Disposing Non-core Assets	(9,785,000)	(15,168,000)	6,584,000
Corporate Adjustments And Eliminations [Member]
Earnings Before Income Taxes:
Gain (Loss) Estimates on Extinguishment of Debt	(95,267,000)	0	0
Intersegment Eliminations [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total Revenue and Other Income	(80,687,000)	(130,721,000)	(143,636,000)
Earnings Before Income Taxes:
Earnings Before Income Taxes	(381,216,000)	(279,503,000)	(267,523,000)
UNITED STATES
Segment Reporting, Revenue Reconciling Item [Line Items]
Total Revenue and Other Income	3,354,581,000	2,999,674,000	2,898,341,000
Europe [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total Revenue and Other Income	91,340,000	83,878,000	187,313,000
South America [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total Revenue and Other Income	21,685,000	29,787,000	169,591,000
CANADA
Segment Reporting, Revenue Reconciling Item [Line Items]
Total Revenue and Other Income	8,494,000	3,575,000	5,692,000
Other Credit Derivatives [Member]
Segment Reporting, Revenue Reconciling Item [Line Items]
Total Revenue and Other Income	$ 0	$ 3,808,000	$ 21,413,000

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