Commitments And Contingencies (Details) a in Millions, CAD in Millions	1 Months Ended		6 Months Ended
	Jul. 31, 2013 USD ($)	Aug. 31, 2011 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2015 CAD	Jun. 30, 2015 USD ($)	Dec. 31, 2010 USD ($)	Mar. 31, 2010 CAD a
Commitments And Contingencies [Abstract]
Investment in New Brunswick towards Company's commitment				CAD 45	$ 44,000,000
Guarantee obligations relative to the firms transportation agreements and gathering project and services					561,000,000
Unrecorded capital investments obligation, Exploration program acres coverage (acres) | a							2.5
Unrecorded capital investments obligation | CAD							CAD 47
Unrecorded promissory note payable | CAD							CAD 45
Promissory note payable, liability recognized					$ 0
Obligation under transportation agreements			$ 8,000,000,000
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