Industry Segment Results (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012
Segment Reporting Information [Line Items]
Sales-Outside	$ 1,125,776	$ 1,189,293	$ 2,351,941	$ 2,500,764
Sales-Purchased Gas	1,406	651	2,764	1,490
Sales-Gas Royalty Interests	17,028	9,533	31,232	21,739
Freight-Outside	10,125	49,472	24,186	98,765
Segment Reporting Information, Intersegment Revenue	0	0	0	0
Total Sales and Freight	1,154,335	1,248,949	2,410,123	2,622,758
Earnings Before Income Taxes	1,809	211,655	510	330,232
Total Assets	12,752,928	12,597,896	12,752,928	12,597,896	12,670,909
Depreciation, Depletion and Amortization	159,307	153,824	320,622	309,171
Capital Expenditures	352,028	407,953	758,000	714,399
Equity in Earnings of Unconsolidated Affiliates			(16,667)	(15,103)
Investments in Unconsolidated Equity Affiliates	256,097		256,097		222,830
Total Reportable Business Segments
Segment Reporting Information [Line Items]
Earnings Before Income Taxes	60,868	258,325	153,730	433,295
Total Assets	11,771,465	11,416,441	11,771,465	11,416,441
Coal
Segment Reporting Information [Line Items]
Sales-Outside	871,071	944,770	1,843,456	1,999,086
Sales-Purchased Gas	0	0	0	0
Sales-Gas Royalty Interests	0	0	0	0
Freight-Outside	10,125	49,472	24,186	98,765
Segment Reporting Information, Intersegment Revenue	0	0	0	0
Total Sales and Freight	881,196	994,242	1,867,642	2,097,851
Earnings Before Income Taxes	65,478	257,181	158,980	419,651
Total Assets	5,600,934	5,445,502	5,600,934	5,445,502
Depreciation, Depletion and Amortization	100,751	100,684	203,462	201,446
Capital Expenditures	157,558	253,587	354,896	448,016
Equity in Earnings of Unconsolidated Affiliates	11,526	1,483	12,343	6,290
Investments in Unconsolidated Equity Affiliates	22,119	21,090	22,119	21,090
Gas
Segment Reporting Information [Line Items]
Sales-Outside	171,236	148,099	339,078	308,302
Sales-Purchased Gas	1,406	651	2,764	1,490
Sales-Gas Royalty Interests	17,028	9,533	31,232	21,739
Freight-Outside	0	0	0	0
Segment Reporting Information, Intersegment Revenue	926	360	1,762	826
Total Sales and Freight	190,596	158,643	374,836	332,357
Earnings Before Income Taxes	(4,610)	1,144	(5,250)	13,644
Total Assets	6,170,531	5,970,939	6,170,531	5,970,939
Depreciation, Depletion and Amortization	52,236	47,326	104,635	96,129
Capital Expenditures	188,463	143,206	395,593	241,661
Equity in Earnings of Unconsolidated Affiliates	1,030	2,037	4,212	3,981
Investments in Unconsolidated Equity Affiliates	170,589	132,545	170,589	132,545
All Other Segments [Member]
Segment Reporting Information [Line Items]
Sales-Outside	83,469	96,424	169,407	193,376
Sales-Purchased Gas	0	0	0	0
Sales-Gas Royalty Interests	0	0	0	0
Freight-Outside	0	0	0	0
Segment Reporting Information, Intersegment Revenue	32,428	36,136	67,905	73,345
Total Sales and Freight	115,897	132,560	237,312	266,721
Earnings Before Income Taxes	(883)	14,962	(41,435)	19,045
Total Assets	363,819	360,673	363,819	360,673
Depreciation, Depletion and Amortization	6,320	(5,782)	12,525	0
Capital Expenditures	6,007	11,160	7,511	24,722
Intersegment Elimination [Member]
Segment Reporting Information [Line Items]
Sales-Outside	0	0	0	0
Sales-Purchased Gas	0	0	0	0
Sales-Gas Royalty Interests	0	0	0	0
Freight-Outside	0	0	0	0
Segment Reporting Information, Intersegment Revenue	(33,354)	(36,496)	(69,667)	(74,171)
Total Sales and Freight	(33,354)	(36,496)	(69,667)	(74,171)
Earnings Before Income Taxes	(58,176)	(61,632)	(111,785)	(122,108)
Total Assets	617,644	820,782	617,644	820,782
Depreciation, Depletion and Amortization	0	11,596	0	11,596
Capital Expenditures	0	0	0	0
All Other
Segment Reporting Information [Line Items]
Equity in Earnings of Unconsolidated Affiliates	(686)	3,648	112	4,832
Investments in Unconsolidated Equity Affiliates	63,389	55,638	63,389	55,638
Steam [Member] \| Coal
Segment Reporting Information [Line Items]
Sales-Outside	697,945	748,303	1,459,217	1,560,356
Sales-Purchased Gas	0	0	0	0
Sales-Gas Royalty Interests	0	0	0	0
Freight-Outside	0	0	0	0
Segment Reporting Information, Intersegment Revenue	0	0	0	0
Total Sales and Freight	697,945	748,303	1,459,217	1,560,356
Earnings Before Income Taxes	103,768	133,697	232,200	262,146
Low Volatile Metallurgical [Member] \| Coal
Segment Reporting Information [Line Items]
Sales-Outside	111,006	120,481	257,834	293,221
Sales-Purchased Gas	0	0	0	0
Sales-Gas Royalty Interests	0	0	0	0
Freight-Outside	0	0	0	0
Segment Reporting Information, Intersegment Revenue	0	0	0	0
Total Sales and Freight	111,006	120,481	257,834	293,221
Earnings Before Income Taxes	30,819	42,780	85,536	122,121
High Volatile Metallurgical [member] \| Coal
Segment Reporting Information [Line Items]
Sales-Outside	57,115	71,250	115,737	131,818
Sales-Purchased Gas	0	0	0	0
Sales-Gas Royalty Interests	0	0	0	0
Freight-Outside	0	0	0	0
Segment Reporting Information, Intersegment Revenue	0	0	0	0
Total Sales and Freight	57,115	71,250	115,737	131,818
Earnings Before Income Taxes	17,245	19,418	30,597	35,354
Other Coal [Member] \| Coal
Segment Reporting Information [Line Items]
Sales-Outside	5,005	4,736	10,668	13,691
Sales-Purchased Gas	0	0	0	0
Sales-Gas Royalty Interests	0	0	0	0
Freight-Outside	10,125	49,472	24,186	98,765
Segment Reporting Information, Intersegment Revenue	0	0	0	0
Total Sales and Freight	15,130	54,208	34,854	112,456
Earnings Before Income Taxes	(86,354)	61,286	(189,353)	30
Coalbed Methane [Member] \| Gas
Segment Reporting Information [Line Items]
Sales-Outside	87,799	88,080	171,439	187,615
Sales-Purchased Gas	0	0	0	0
Sales-Gas Royalty Interests	0	0	0	0
Freight-Outside	0	0	0	0
Segment Reporting Information, Intersegment Revenue	0	0	0	0
Total Sales and Freight	87,799	88,080	171,439	187,615
Earnings Before Income Taxes	22,124	24,344	43,436	60,734
Marcellus Shale [Member] \| Gas
Segment Reporting Information [Line Items]
Sales-Outside	46,577	23,730	94,988	47,521
Sales-Purchased Gas	0	0	0	0
Sales-Gas Royalty Interests	0	0	0	0
Freight-Outside	0	0	0	0
Segment Reporting Information, Intersegment Revenue	0	0	0	0
Total Sales and Freight	46,577	23,730	94,988	47,521
Earnings Before Income Taxes	11,680	4,835	25,448	8,086
Conventional Gas [Member] \| Gas
Segment Reporting Information [Line Items]
Sales-Outside	33,745	34,207	66,181	68,580
Sales-Purchased Gas	0	0	0	0
Sales-Gas Royalty Interests	0	0	0	0
Freight-Outside	0	0	0	0
Segment Reporting Information, Intersegment Revenue	0	0	0	0
Total Sales and Freight	33,745	34,207	66,181	68,580
Earnings Before Income Taxes	(5,576)	(2,410)	(9,737)	(6,132)
Other Gas \| Gas
Segment Reporting Information [Line Items]
Sales-Outside	3,115	2,082	6,470	4,586
Sales-Purchased Gas	1,406	651	2,764	1,490
Sales-Gas Royalty Interests	17,028	9,533	31,232	21,739
Freight-Outside	0	0	0	0
Segment Reporting Information, Intersegment Revenue	926	360	1,762	826
Total Sales and Freight	22,475	12,626	42,228	28,641
Earnings Before Income Taxes	(32,838)	(25,625)	(64,397)	(49,044)
First Energy [Member] \| Coal
Segment Reporting Information [Line Items]
Entity-Wide Revenue, Major Customer, Amount	157,318	136,576	328,300	280,731
XCoal Energy and Resources [Member] \| Coal
Segment Reporting Information [Line Items]
Entity-Wide Revenue, Major Customer, Amount	$ 138,700	$ 181,566	$ 321,821	$ 319,907

Revenue from the sale of oil and gas which is sold by CNX on behalf of the royalty owner.

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