Guarantor Subsidiaries Balance Sheet (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Dec. 31, 2011
Current Assets:
Cash and Cash Equivalents	$ 21,086	$ 21,878	$ 230,958	$ 375,736
Accounts and Notes Receivable:
Trade	436,388	428,328
Notes Receivable, Related Parties, Current	25,813	318,387
Other Receivables	160,931	131,131
Accounts Receivable - Securitized	44,364	37,846
Inventories	238,348	247,766
Deferred Income Taxes	81,825	148,104
Restricted Cash and Cash Equivalents, Current	12,263	48,294
Prepaid Expenses	162,418	157,360
Total Current Assets	1,183,436	1,539,094
Property, Plant and Equipment:
Property, Plant and Equipment	16,571,104	15,545,204
Less-Accumulated Depreciation, Depletion and Amortization	5,940,247	5,354,237
Total Property, Plant and Equipment-Net	10,630,857	10,190,967
Other Assets:
Deferred Income Taxes	457,105	444,585
Restricted Cash and Cash Equivalents, Noncurrent	0	20,379
Investments in Unconsolidated Equity Affiliates	261,218	222,830
Notes, Loans and Financing Receivable, Net	155	25,977
Other	204,301	227,077
Total Other Assets	922,779	940,848
Total Assets	12,737,072	12,670,909	12,556,594
Current Liabilities:
Accounts Payable	512,182	507,982
Accounts Payable (Recoverable)- Related Parties	0	0
Short-Term Notes Payable		25,073
Current Portion Long-Term Debt	13,182	13,485
Short-Term Notes Payable	47,000	25,073
Secured Debt, Current	44,364	37,846
Accrued Income Taxes, Current	87,965	34,219
Other Accrued Liabilities	868,904	768,494
Total Current Liabilities	1,573,597	1,387,099
Long-Term Debt:	3,171,931	3,174,586
Deferred Credits and Other Liabilities
Postretirement Benefits Other Than Pensions	2,814,234	2,832,401
Pneumoconiosis	178,508	174,781
Mine Closing	460,515	446,727
Gas Well Closing	197,093	148,928
Workers' Compensation	156,568	155,648
Salary Retirement	74,108	218,004
Reclamation	49,487	47,965
Other	103,855	131,025
Total Deferred Credits and Other Liabilities	4,034,368	4,155,479
Total CONSOL Energy Inc. Stockholders' Equity	3,958,165	3,953,792
Noncontrolling Interest	(989)	(47)
TOTAL LIABILITIES AND EQUITY	12,737,072	12,670,909
Parent Issuer [Member]
Current Assets:
Cash and Cash Equivalents	16,187	17,491
Accounts and Notes Receivable:
Trade	0	0
Notes Receivable, Related Parties, Current	1,193	154
Other Receivables	3,866	6,335
Accounts Receivable - Securitized	0	0
Inventories	0	0
Deferred Income Taxes	106,291	174,176
Restricted Cash and Cash Equivalents, Current	0	0
Prepaid Expenses	37,054	29,589
Total Current Assets	164,591	227,745
Property, Plant and Equipment:
Property, Plant and Equipment	218,303	216,448
Less-Accumulated Depreciation, Depletion and Amortization	139,157	126,048
Total Property, Plant and Equipment-Net	79,146	90,400
Other Assets:
Deferred Income Taxes	875,354	884,310
Restricted Cash and Cash Equivalents, Noncurrent		0
Investments in Unconsolidated Equity Affiliates	10,234,178	9,917,050
Notes, Loans and Financing Receivable, Net	155	239
Other	109,998	118,938
Total Other Assets	11,219,685	10,920,537
Total Assets	11,463,422	11,238,682
Current Liabilities:
Accounts Payable	193,491	177,734
Accounts Payable (Recoverable)- Related Parties	3,882,644	3,599,216
Short-Term Notes Payable		25,073
Current Portion Long-Term Debt	1,454	1,554
Short-Term Notes Payable	0
Secured Debt, Current	0	0
Accrued Income Taxes, Current	64,059	20,488
Other Accrued Liabilities	209,321	135,407
Total Current Liabilities	4,350,969	3,959,472
Long-Term Debt:	3,004,976	3,005,515
Deferred Credits and Other Liabilities
Postretirement Benefits Other Than Pensions	0	0
Pneumoconiosis	0	0
Mine Closing	0	0
Gas Well Closing	0	0
Workers' Compensation	0	0
Salary Retirement	74,108	218,004
Reclamation	0	0
Other	75,204	101,899
Total Deferred Credits and Other Liabilities	149,312	319,903
Total CONSOL Energy Inc. Stockholders' Equity	3,958,165	3,953,792
Noncontrolling Interest	0	0
TOTAL LIABILITIES AND EQUITY	11,463,422	11,238,682
CNX Gas Guarantor [Member]
Current Assets:
Cash and Cash Equivalents	3,847	3,352
Accounts and Notes Receivable:
Trade	60,255	58,126
Notes Receivable, Related Parties, Current	0	315,730
Other Receivables	144,253	214,748
Accounts Receivable - Securitized	0	0
Inventories	15,679	14,133
Deferred Income Taxes	(24,466)	(26,072)
Restricted Cash and Cash Equivalents, Current	0	0
Prepaid Expenses	81,970	86,186
Total Current Assets	281,538	666,203
Property, Plant and Equipment:
Property, Plant and Equipment	6,586,647	5,956,207
Less-Accumulated Depreciation, Depletion and Amortization	1,122,401	960,613
Total Property, Plant and Equipment-Net	5,464,246	4,995,594
Other Assets:
Deferred Income Taxes	(418,249)	(439,725)
Restricted Cash and Cash Equivalents, Noncurrent		0
Investments in Unconsolidated Equity Affiliates	183,895	143,876
Notes, Loans and Financing Receivable, Net	0	0
Other	39,916	65,935
Total Other Assets	(194,438)	(229,914)
Total Assets	5,551,346	5,431,883
Current Liabilities:
Accounts Payable	257,487	166,182
Accounts Payable (Recoverable)- Related Parties	39,594	23,981
Short-Term Notes Payable		0
Current Portion Long-Term Debt	6,036	5,953
Short-Term Notes Payable	85,500
Secured Debt, Current	0	0
Accrued Income Taxes, Current	23,906	13,731
Other Accrued Liabilities	70,835	57,074
Total Current Liabilities	483,358	266,921
Long-Term Debt:	43,682	46,081
Deferred Credits and Other Liabilities
Postretirement Benefits Other Than Pensions	0	0
Pneumoconiosis	0	0
Mine Closing	0	0
Gas Well Closing	118,075	80,097
Workers' Compensation	0	0
Salary Retirement	0	0
Reclamation	0	0
Other	12,227	24,518
Total Deferred Credits and Other Liabilities	130,302	104,615
Total CONSOL Energy Inc. Stockholders' Equity	4,894,993	5,014,313
Noncontrolling Interest	(989)	(47)
TOTAL LIABILITIES AND EQUITY	5,551,346	5,431,883
Other Guarantors Subsidiaries [Member]
Current Assets:
Cash and Cash Equivalents	0	175
Accounts and Notes Receivable:
Trade	0	0
Notes Receivable, Related Parties, Current	24,620	2,503
Other Receivables	7,780	33,289
Accounts Receivable - Securitized	0	0
Inventories	184,877	198,269
Deferred Income Taxes	0	0
Restricted Cash and Cash Equivalents, Current	12,263	48,294
Prepaid Expenses	41,981	40,215
Total Current Assets	271,521	322,745
Property, Plant and Equipment:
Property, Plant and Equipment	9,740,510	9,347,370
Less-Accumulated Depreciation, Depletion and Amortization	4,659,763	4,249,507
Total Property, Plant and Equipment-Net	5,080,747	5,097,863
Other Assets:
Deferred Income Taxes	0	0
Restricted Cash and Cash Equivalents, Noncurrent		20,379
Investments in Unconsolidated Equity Affiliates	750,771	769,058
Notes, Loans and Financing Receivable, Net	0	25,738
Other	44,822	32,016
Total Other Assets	795,593	847,191
Total Assets	6,147,861	6,267,799
Current Liabilities:
Accounts Payable	48,128	154,936
Accounts Payable (Recoverable)- Related Parties	(4,202,168)	(3,749,584)
Short-Term Notes Payable		0
Current Portion Long-Term Debt	4,914	5,222
Short-Term Notes Payable	0
Secured Debt, Current	0	0
Accrued Income Taxes, Current	0	0
Other Accrued Liabilities	578,019	566,485
Total Current Liabilities	(3,571,107)	(3,022,941)
Long-Term Debt:	121,864	121,523
Deferred Credits and Other Liabilities
Postretirement Benefits Other Than Pensions	2,814,234	2,832,401
Pneumoconiosis	178,508	174,781
Mine Closing	460,515	446,727
Gas Well Closing	79,018	68,831
Workers' Compensation	156,242	155,342
Salary Retirement	0	0
Reclamation	49,487	47,965
Other	16,424	4,608
Total Deferred Credits and Other Liabilities	3,754,428	3,730,655
Total CONSOL Energy Inc. Stockholders' Equity	5,842,676	5,438,562
Noncontrolling Interest	0	0
TOTAL LIABILITIES AND EQUITY	6,147,861	6,267,799
Non-Guarantors [Member]
Current Assets:
Cash and Cash Equivalents	1,052	860
Accounts and Notes Receivable:
Trade	376,133	370,202
Notes Receivable, Related Parties, Current	0	0
Other Receivables	5,032	5,159
Accounts Receivable - Securitized	44,364	37,846
Inventories	37,792	35,364
Deferred Income Taxes	0	0
Restricted Cash and Cash Equivalents, Current	0	0
Prepaid Expenses	1,413	1,370
Total Current Assets	465,786	450,801
Property, Plant and Equipment:
Property, Plant and Equipment	25,644	25,179
Less-Accumulated Depreciation, Depletion and Amortization	18,926	18,069
Total Property, Plant and Equipment-Net	6,718	7,110
Other Assets:
Deferred Income Taxes	0	0
Restricted Cash and Cash Equivalents, Noncurrent		0
Investments in Unconsolidated Equity Affiliates	0	0
Notes, Loans and Financing Receivable, Net	0	0
Other	9,565	10,188
Total Other Assets	9,565	10,188
Total Assets	482,069	468,099
Current Liabilities:
Accounts Payable	13,076	9,130
Accounts Payable (Recoverable)- Related Parties	241,430	254,787
Short-Term Notes Payable		0
Current Portion Long-Term Debt	778	756
Short-Term Notes Payable	0
Secured Debt, Current	44,364	37,846
Accrued Income Taxes, Current	0	0
Other Accrued Liabilities	10,729	9,528
Total Current Liabilities	310,377	312,047
Long-Term Debt:	1,409	1,467
Deferred Credits and Other Liabilities
Postretirement Benefits Other Than Pensions	0	0
Pneumoconiosis	0	0
Mine Closing	0	0
Gas Well Closing	0	0
Workers' Compensation	326	306
Salary Retirement	0	0
Reclamation	0	0
Other	0	0
Total Deferred Credits and Other Liabilities	326	306
Total CONSOL Energy Inc. Stockholders' Equity	169,957	154,279
Noncontrolling Interest	0	0
TOTAL LIABILITIES AND EQUITY	482,069	468,099
Consolidation, Eliminations [Member]
Current Assets:
Cash and Cash Equivalents	0	0
Accounts and Notes Receivable:
Trade	0	0
Notes Receivable, Related Parties, Current	0	0
Other Receivables	0	(128,400)
Accounts Receivable - Securitized	0	0
Inventories	0	0
Deferred Income Taxes	0	0
Restricted Cash and Cash Equivalents, Current	0	0
Prepaid Expenses	0	0
Total Current Assets	0	(128,400)
Property, Plant and Equipment:
Property, Plant and Equipment	0	0
Less-Accumulated Depreciation, Depletion and Amortization	0	0
Total Property, Plant and Equipment-Net	0	0
Other Assets:
Deferred Income Taxes	0	0
Restricted Cash and Cash Equivalents, Noncurrent		0
Investments in Unconsolidated Equity Affiliates	(10,907,626)	(10,607,154)
Notes, Loans and Financing Receivable, Net	0	0
Other	0	0
Total Other Assets	(10,907,626)	(10,607,154)
Total Assets	(10,907,626)	(10,735,554)
Current Liabilities:
Accounts Payable	0	0
Accounts Payable (Recoverable)- Related Parties	38,500	(128,400)
Short-Term Notes Payable		0
Current Portion Long-Term Debt	0	0
Short-Term Notes Payable	(38,500)
Secured Debt, Current	0	0
Accrued Income Taxes, Current	0	0
Other Accrued Liabilities	0	0
Total Current Liabilities	0	(128,400)
Long-Term Debt:	0	0
Deferred Credits and Other Liabilities
Postretirement Benefits Other Than Pensions	0	0
Pneumoconiosis	0	0
Mine Closing	0	0
Gas Well Closing	0	0
Workers' Compensation	0	0
Salary Retirement	0	0
Reclamation	0	0
Other	0	0
Total Deferred Credits and Other Liabilities	0	0
Total CONSOL Energy Inc. Stockholders' Equity	(10,907,626)	(10,607,154)
Noncontrolling Interest	0	0
TOTAL LIABILITIES AND EQUITY	$ (10,907,626)	$ (10,735,554)