Commitments and Contingencies Commitments and Contingencies (Details) (USD $)	3 Months Ended	1 Months Ended
	Mar. 31, 2014 CONSOL Carried Cost Obligation [Member]	Feb. 28, 2014 Marcellus Shale Firm Transportation Agreement [Member] MMBTU
Other Commitments [Line Items]
Maximum amount to be paid each calendar year for funding of future drilling and completion costs	$ 400,000,000
Equity Method Investment, Ownership Percentage	50.00%
Funding of joint venture's future drilling and completion costs	2,100,000,000
Natural gas price agreed upon benchmark, average	4.00
Forecast On Venture To Explore and Develop Oil and Gas Properties	235,000,000
Long-term Purchase Commitment, Minimum Volume Required Per Day		150,000
Long-term Purchase Commitment, Amount		$ 765,000,000
Long-term Purchase Commitment, Time Period		15 years