Guarantor Subsidiaries, Condensed Statement of Cash Flows (Detail) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Schedule of Condensed Consolidating Statement of Cash Flows [Line Items]
Net Cash Provided by Operating Activities	$ 1,527,606,000	$ 1,131,312,000	$ 1,060,451,000
Investing Activities:
Capital Expenditures	(1,382,371,000)	(1,154,024,000)	(920,080,000)
Acquisition of Dominion Exploration and Production Business	0	(3,470,212,000)	0
Purchase of CNX Gas Noncontrolling Interest		991,034,000
Net Investment in Equity Affiliates	55,876,000	11,452,000	4,855,000
Other Investing Activities	(747,971,000)	(59,844,000)	69,884,000
Net Cash Used in Investing Activities	(578,524,000)	(5,543,974,000)	(845,341,000)
Financing Activities:
Dividends Paid	(96,356,000)	(85,861,000)	(72,292,000)
(Payments on) Proceeds from Short-Term Borrowings	(284,000,000)	(188,850,000)	(84,850,000)
Payments on Securitization Facility	(200,000,000)		115,000,000
Proceeds from Accounts Receivable Securitization		150,000,000
Payments On Long Term Notes Including Redemption Premium	(265,785,000)	0	0
Proceeds from Issuance of Long-Term Notes	250,000,000	2,750,000,000	0
Debt Issuance and Financing Fees	(15,686,000)	(84,248,000)
Proceeds from Issuance of Common Stock	0	1,828,862,000	0
Proceeds from Parent		0
Other Financing Activities	5,687,000	9,946,000	(15,873,000)
Net Cash (Used in) Provided by Financing Activities	(606,140,000)	4,379,849,000	(288,015,000)
Parent Issuer
Schedule of Condensed Consolidating Statement of Cash Flows [Line Items]
Net Cash Provided by Operating Activities	530,444,000	93,623,000	179,095,000
Investing Activities:
Capital Expenditures	41,172,000	0	0
Acquisition of Dominion Exploration and Production Business		0
Purchase of CNX Gas Noncontrolling Interest		991,034,000
Net Investment in Equity Affiliates	0	3,470,212,000	0
Other Investing Activities	(10,000)	0	0
Net Cash Used in Investing Activities	(41,162,000)	(4,461,246,000)	0
Financing Activities:
Dividends Paid	96,356,000	85,861,000	(72,292,000)
(Payments on) Proceeds from Short-Term Borrowings	(155,000,000)	(260,000,000)	(70,000,000)
Payments on Securitization Facility	(200,000,000)		115,000,000
Proceeds from Accounts Receivable Securitization		150,000,000
Payments On Long Term Notes Including Redemption Premium	265,785,000
Proceeds from Issuance of Long-Term Notes	250,000,000	2,750,000,000
Debt Issuance and Financing Fees	(10,628,000)	(84,248,000)
Proceeds from Issuance of Common Stock		1,828,862,000
Proceeds from Parent		0
Other Financing Activities	16,377,000	20,703,000	5,275,000
Net Cash (Used in) Provided by Financing Activities	(461,392,000)	4,319,456,000	(252,017,000)
Cnx Gas Guarantor [Member]
Schedule of Condensed Consolidating Statement of Cash Flows [Line Items]
Net Cash Provided by Operating Activities	329,360,000	361,073,000	360,163,000
Investing Activities:
Capital Expenditures	664,612,000	421,428,000	(336,447,000)
Acquisition of Dominion Exploration and Production Business		0
Purchase of CNX Gas Noncontrolling Interest		0
Net Investment in Equity Affiliates	(50,626,000)	(1,501,000)	1,250,000
Other Investing Activities	(746,956,000)	(562,000)	288,000
Net Cash Used in Investing Activities	132,970,000	(419,365,000)	(334,909,000)
Financing Activities:
Dividends Paid	0	0	0
(Payments on) Proceeds from Short-Term Borrowings	(129,000,000)	71,150,000	(14,850,000)
Payments on Securitization Facility	0		0
Proceeds from Accounts Receivable Securitization		0
Payments On Long Term Notes Including Redemption Premium	0
Proceeds from Issuance of Long-Term Notes	0	0
Debt Issuance and Financing Fees	(5,058,000)	0
Proceeds from Issuance of Common Stock		0
Proceeds from Parent		0
Other Financing Activities	(8,104,000)	2,577,000	(11,206,000)
Net Cash (Used in) Provided by Financing Activities	(142,162,000)	73,727,000	(26,056,000)
Other Subsidiary Guarantors
Schedule of Condensed Consolidating Statement of Cash Flows [Line Items]
Net Cash Provided by Operating Activities	669,704,000	675,627,000	523,596,000
Investing Activities:
Capital Expenditures	676,587,000	732,596,000	(583,633,000)
Acquisition of Dominion Exploration and Production Business		3,470,212,000
Purchase of CNX Gas Noncontrolling Interest		0
Net Investment in Equity Affiliates	(5,250,000)	(9,951,000)	3,605,000
Other Investing Activities	469,000	(59,282,000)	69,596,000
Net Cash Used in Investing Activities	(671,806,000)	(4,133,575,000)	(510,432,000)
Financing Activities:
Dividends Paid	0	0	0
(Payments on) Proceeds from Short-Term Borrowings	0	0	0
Payments on Securitization Facility	0		0
Proceeds from Accounts Receivable Securitization		0
Payments On Long Term Notes Including Redemption Premium	0
Proceeds from Issuance of Long-Term Notes	0	0
Debt Issuance and Financing Fees	0	0
Proceeds from Issuance of Common Stock		0
Proceeds from Parent		3,470,212,000
Other Financing Activities	(1,793,000)	(12,793,000)	(9,481,000)
Net Cash (Used in) Provided by Financing Activities	(1,793,000)	3,457,419,000	(9,481,000)
Non-Guarantors
Schedule of Condensed Consolidating Statement of Cash Flows [Line Items]
Net Cash Provided by Operating Activities	(1,902,000)	989,000	(2,403,000)
Investing Activities:
Capital Expenditures	0	0	0
Acquisition of Dominion Exploration and Production Business		0
Purchase of CNX Gas Noncontrolling Interest		0
Net Investment in Equity Affiliates	0	0	0
Other Investing Activities	(1,474,000)	0	0
Net Cash Used in Investing Activities	1,474,000	0	0
Financing Activities:
Dividends Paid	0	0	0
(Payments on) Proceeds from Short-Term Borrowings	0	0	0
Payments on Securitization Facility	0		0
Proceeds from Accounts Receivable Securitization		0
Payments On Long Term Notes Including Redemption Premium	0
Proceeds from Issuance of Long-Term Notes	0	0
Debt Issuance and Financing Fees	0	0
Proceeds from Issuance of Common Stock		0
Proceeds from Parent		0
Other Financing Activities	(793,000)	(541,000)	(461,000)
Net Cash (Used in) Provided by Financing Activities	(793,000)	(541,000)	(461,000)
Elimination
Schedule of Condensed Consolidating Statement of Cash Flows [Line Items]
Net Cash Provided by Operating Activities	0	0	0
Investing Activities:
Capital Expenditures	0	0	0
Acquisition of Dominion Exploration and Production Business		0
Purchase of CNX Gas Noncontrolling Interest		0
Net Investment in Equity Affiliates	0	(3,470,212,000)	0
Other Investing Activities	0	0	0
Net Cash Used in Investing Activities	0	3,470,212,000	0
Financing Activities:
Dividends Paid	0	0	0
(Payments on) Proceeds from Short-Term Borrowings	0	0	0
Payments on Securitization Facility	0		0
Proceeds from Accounts Receivable Securitization		0
Payments On Long Term Notes Including Redemption Premium	0
Proceeds from Issuance of Long-Term Notes	0	0
Debt Issuance and Financing Fees	0	0
Proceeds from Issuance of Common Stock		0
Proceeds from Parent		(3,470,212,000)
Other Financing Activities	0	0	0
Net Cash (Used in) Provided by Financing Activities	$ 0	$ (3,470,212,000)	$ 0