Consolidated Statements of Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Oil and Gas Sales Revenue	$ 793,248	$ 726,921	$ 1,004,924
Gain (Loss) on Hedging Activity	(141,021)	392,942	23,193
Coal Products and Services Revenue	1,065,582	1,289,036	1,616,874
Other Revenue, Net	32,038	30,967	276,242
Gas Royalty Interests and Purchased Gas Sales	43,256	14,450	8,999
Freight-Outside	46,468	20,499	23,133
Other Income	167,306	144,351	207,460
Gain (Loss) on Disposition of Assets	19,498	74,173	43,198
Total Revenue and Other Income	2,026,375	2,693,339	3,204,023
Oil and Gas Property, Lease Operating Expense	96,434	121,847	139,242
Gas Gathering, Transportation, Marketing and Processing Costs	374,350	343,403	239,579
Production Tax Expense	31,049	30,438	39,418
E&P Depreciation, Depletion, and Amortization	417,853	370,374	323,600
Exploration and Production Costs	14,519	10,120	23,355
Production Royalty Interests and Purchased Gas Costs	42,717	10,721	7,251
Other Expenses	87,913	65,939	46,838
Impairment of Oil and Gas Properties	0	828,905	0
Results of Operations, General and Administrative Related to Oil and Gas Producing Activities	102,503	102,229	128,731
Oil and Gas Production Expense	1,167,338	1,883,976	948,014
Operating Expenses	733,300	666,302	982,749
Coal Depreciation, Depletion, Amortization	168,195	176,864	173,316
Freight Expense	46,468	20,499	23,133
General and Administrative Expense	37,512	40,843	68,597
Cost of Coal Products and Services	985,475	904,508	1,247,795
Other Nonoperating Expense	182,869	78,743	460,429
Other General and Administrative Expense	12,717	14,918	13,307
Depreciation, Depletion and Amortization, Nonproduction	12,455	19,882	35,727
Gains (Losses) on Extinguishment of Debt	0	67,751	95,267
Interest Expense	191,476	199,266	223,333
Other General Expense	399,517	380,560	828,063
Total Costs	2,552,330	3,169,044	3,023,872
Earnings Before Income Taxes	(525,955)	(475,705)	180,151
Income Taxes	10,010	(125,439)	15,204
Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest	(535,965)	(350,266)	164,947
Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent	(303,183)	(14,209)	(1,857)
Net Income (Loss)	(839,148)	(364,475)	163,090
Less: Net Loss (Income) Attributable to Noncontrolling Interest	(8,954)	(10,410)	0
Net Income Attributable to CONSOL Energy Inc Shareholders	$ (848,102)	$ (374,885)	$ 163,090
Earnings per share:
Income (Loss) from Continuing Operations, Per Basic Share	$ (2.38)	$ (1.57)	$ 0.72
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share	(1.32)	(0.07)	(0.01)
Basic	(3.70)	(1.64)	0.71
Income (Loss) from Continuing Operations, Per Diluted Share	(2.38)	(1.57)	0.71
Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share	(1.32)	(0.07)	(0.01)
Dilutive	(3.70)	(1.64)	0.70
Dividends Paid Per Share	$ 0.01	$ 0.15	$ 0.25