Supplemental Oil And Gas Disclosures (Schedule Of Prices Weighted By Field Production Related To The Proved Reserves) (Details)

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Supplemental Oil And Gas Disclosures (Schedule Of Prices Weighted By Field Production Related To The Proved Reserves) (Details)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009	Dec. 31, 2008
Oil [Member]
Reserve Quantities [Line Items]
Weighted price	97.36	76.28	55.87	38.85
Natural Gas Liquids [Member]
Reserve Quantities [Line Items]
Weighted price	51.30	44.92	33.36	25.90
Natural Gas [Member]
Reserve Quantities [Line Items]
Weighted price	4.11	4.57	3.80	6.17