Delivery Commitments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2013 bbls MBbls MMBTU
Delivery Commitments [Line Items]
Delivery Commitments, Current (2014)		7,483,000
Delivery Commitments, Due In Two Years (2015)		7,483,000
Delivery Commitments, Due In Three Years (2016)		9,190,000
Delivery Commitments, Due In Four Years (2017)		13,870,000
Delivery Commitments, Due In Five Years (2018)		13,870,000
Delivery Commitments, Due Thereafter		50,748,000
Total Delivery Commitments		102,644,000
Natural Gas Commitments, Current (2014)		11,250,000
Natural Gas Commitments, Due In Two Years (2015)		0
Natural Gas Commitments, Due In Three Years (2016)		0
Natural Gas Commitments, Due In Four Years (2017)		0
Natural Gas Commitments, Due In Five Years (2018)		0
Natural Gas Commitments, Due Thereafter		0
Total Natural Gas Commitments		11,250,000
Oil and Gas Delivery Commitments and Contracts Additional Information [Abstract]
Oil and Gas Delivery Commitments and Contracts, Term in Years		10 years 0 months 0 days
Oil and Gas Delivery Commitments and Contracts, Daily Production		20,000
Gain (Loss) Related to Litigation Settlement	$ 13
Commitment Volumes 2024		7,300
Minimum [Member]
Delivery Commitments [Line Items]
Deficiency Fees		2.67
Maximum [Member]
Delivery Commitments [Line Items]
Deficiency Fees		6.50