Commitments And Contingencies (Details)	0 Months Ended	1 Months Ended		9 Months Ended								1 Months Ended
	Aug. 24, 2011 USD ($)	Jul. 31, 2013 USD ($)	Dec. 31, 2010 item	Sep. 30, 2014 USD ($)	Sep. 30, 2014 CAD	Feb. 28, 2014 USD ($)	Mar. 31, 2010 CAD acre	Feb. 28, 2009 USD ($)	Sep. 30, 2014 Arkansas Royalty Litigation [Member] lawsuit	Sep. 30, 2014 Arkansas Royalty Litigation [Member] Arkansas State Court [Member] lawsuit	Sep. 30, 2014 Arkansas Royalty Litigation [Member] Federal Court [Member] lawsuit	Dec. 31, 2012 Licensing Agreement [Member]
Commitments And Contingencies [Line Items]
Unrecorded capital investments obligation, Exploration program acres coverage (acres)							2,500,000
Unrecorded capital investments obligation							47,000,000
Period licenses require capital investments be made, years				3 years
Unrecorded promissory note payable							45,000,000
Obligations for demand and similar charges under transportation agreements				44,000,000	44,000,000
Extension expiration												Mar. 16, 2015
Promissory note payable, liability recognized				0
Obligation under transportation agreements				3,800,000,000
Guarantee obligations relative to the firms transportation agreements and gathering project and services				100,000,000
Number of prospects			2
Litigation settlement, gross	11,000,000
Litigation, portion of profits considered for disgorgement								382,000,000
Disgorgement damages awarded in favor of the plaintiff and intervenor	24,000,000
Litigation, interest and attorney's fees claimed by plaintiffs	9,000,000					11,000,000
Disgorgement recoverable by plaintiff to be reversed		24,000,000
Actual damages recoverable by plaintiff to be reversed		11,000,000
Litigation settlement upheld		$ 11,000,000
Number of cases									3	2	1