Long-Term Debt (Details) (USD $)	12 Months Ended				0 Months Ended	12 Months Ended				0 Months Ended	12 Months Ended					12 Months Ended				0 Months Ended	12 Months Ended										12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Oct. 03, 2013 Credit Facility, due October 3, 2018	Dec. 31, 2013 Credit Facility, due October 3, 2018		Dec. 31, 2012 Credit Facility, due October 3, 2018		Sep. 01, 2013 CONSOL Installment Payment	Dec. 31, 2013 CONSOL Installment Payment	Dec. 31, 2012 CONSOL Installment Payment		Dec. 31, 2013 Capital Lease and Other Obligations	Dec. 31, 2012 Capital Lease and Other Obligations	Dec. 31, 2013 5¼% Senior Notes, due April 15, 2014	Dec. 31, 2012 5¼% Senior Notes, due April 15, 2014	Dec. 31, 2013 8¼% Senior Notes, due March 1, 2019	Dec. 31, 2012 8¼% Senior Notes, due March 1, 2019	Nov. 08, 2013 4.15% Senior Notes, due December 15, 2021	Dec. 31, 2013 4.15% Senior Notes, due December 15, 2021	Dec. 31, 2012 4.15% Senior Notes, due December 15, 2021	Dec. 31, 2013 7¼% Senior Notes, due October 15, 2023	Dec. 31, 2012 7¼% Senior Notes, due October 15, 2023	Dec. 31, 2013 8% Senior Notes, due April 1, 2027	Dec. 31, 2012 8% Senior Notes, due April 1, 2027	Dec. 31, 2013 6% Senior Notes, due March 1, 2041	Dec. 31, 2012 6% Senior Notes, due March 1, 2041	Dec. 31, 2013 5¼% Senior Notes, due November 15, 2043	Dec. 31, 2012 5¼% Senior Notes, due November 15, 2043	Dec. 31, 2013 7¼% Senior Debentures, due August 1, 2097	Dec. 31, 2012 7¼% Senior Debentures, due August 1, 2097	Dec. 31, 2012 CONSOL
Debt Instrument [Line Items]
Debt	$ 4,843,000,000		$ 4,123,000,000			$ 0	[1]	$ 0	[1]		$ 0	$ 328,000,000		$ 359,000,000	$ 311,000,000	$ 200,000,000	$ 200,000,000	$ 1,000,000,000	$ 1,000,000,000	$ 1,000,000,000	$ 1,000,000,000	$ 1,000,000,000	$ 100,000,000	$ 100,000,000	$ 250,000,000	$ 250,000,000	$ 850,000,000	$ 850,000,000	$ 1,000,000,000	$ 0	$ 84,000,000	$ 84,000,000
Interest Rate						0.00%	[1]	0.00%	[1]		0.00%	1.79%	[2]	0.00%	0.00%	5.25%	5.25%	8.25%	8.25%	5.25%	4.15%	4.15%	7.25%	7.25%	8.00%	8.00%	6.00%	6.00%	5.25%	0.00%	7.25%	7.25%
Debt Instrument, Maturity Date						Oct. 03, 2018		Oct. 14, 2016			Sep. 30, 2013	Sep. 30, 2013				Apr. 15, 2014	Apr. 15, 2014	Mar. 01, 2019	Mar. 01, 2019		Dec. 15, 2021	Dec. 15, 2021	Oct. 15, 2023	Oct. 15, 2023	Apr. 01, 2027	Apr. 01, 2027	Mar. 01, 2041	Mar. 01, 2041	Nov. 15, 2043		Aug. 01, 2097	Aug. 01, 2097
Debt Instrument, Maturity Date Range, Start												Sep. 30, 2012
Unamortized Discount	(19,000,000)		(15,000,000)
Total Debt, Net of Discount	4,824,000,000		4,108,000,000
Long-term Debt and Capital Lease Obligations, Current											(200,000,000)			(58,000,000)	(48,000,000)
Notes and Loans Payable, Current	(200,000,000)	[3]	(324,000,000)	[3]								(324,000,000)
Long-Term Debt Due After One Year	4,566,000,000		3,736,000,000
Unamortized Debt Issuance Costs	41,000,000																			6,000,000
Debt Issuance Proceeds Used To Extinguish Outstanding Debt																				900,000,000
Debt Instrument, Offering Date					Oct. 03, 2013					Sep. 30, 2011										Nov. 08, 2013
Debt offerings proceeds, net of discount and underwriting fees																				985,000,000
Installment payment amount for joint venture partnership																																	328,000,000
Line of Credit Facility, Maximum Borrowing Capacity					4,000,000,000	4,000,000,000
Credit facility fee rate basis points, minimum					0.125%
Credit facility fee rate basis points, maximum					0.30%
Credit facility interest rate, Eurodollar rate plus, minimum					1.00%
Credit facility interest rate, Eurodollar rate plus, maximum					1.45%
Credit facility aggregate short-term loans and letters of credit, maximum					500,000,000
Credit facility covenant term debt to capitalization ratio maximum					65.00%
Repayments of Long-term Debt [Abstract]
2014	200,000,000
2015	0
2016	0
2017	0
2018	0
Thereafter	4,284,000,000
Total	$ 4,484,000,000

[1] Our Credit Agreement provides for a $4.0 billion Credit Facility. The Credit Facility is available for general corporate purposes.

[2] Imputed rate based on the prevailing market rates for similar debt instruments at the date of assessment.

[3] See Note 10. Long-Term Debt.