Delivery Commitments (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2014 bbls
Delivery Commitments [Line Items]
Delivery Commitments, Current (2015)		6,570,000
Delivery Commitments, Due In Two Years (2016)		13,908,000
Delivery Commitments, Due In Three Years (2017)		13,870,000
Delivery Commitments, Due In Four Years (2018)		13,870,000
Delivery Commitments, Due In Five Years (2019)		13,870,000
Delivery Commitments, Due Thereafter		46,576,000
Total Delivery Commitments		108,664,000
Natural Gas Commitments, Current (2015)		15,372,000
Natural Gas Commitments, Due In Two Years (2016)		0
Natural Gas Commitments, Due In Three Years (2017)		0
Natural Gas Commitments, Due In Four Years (2018)		0
Natural Gas Commitments, Due In Five Years (2019)		0
Natural Gas Commitments, Due Thereafter		0
Total Natural Gas Commitments		15,372,000
Oil and Gas Delivery Commitments and Contracts Additional Information [Abstract]
Gain (Loss) Related to Litigation Settlement	$ 13
Commitment Volumes 2025		7,300
Minimum [Member]
Delivery Commitments [Line Items]
Deficiency Fees		1.83
Maximum [Member]
Delivery Commitments [Line Items]
Deficiency Fees		6.50
2016 to 2025 [Member]
Delivery Commitments [Line Items]
Oil and Gas Delivery Commitments and Contracts, Daily Production		20,000
2020 [Member]
Delivery Commitments [Line Items]
Oil and Gas Delivery Commitments and Contracts, Daily Production		18,000