Major Customers And Derivative Counterparties (Consolidated Oil, NGL And Gas Revenues) (Details)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Plains Marketing LP [Member]
Consolidated oil, NGL and gas revenues represented by the company's purchases	16.00%	12.00%	10.00%
Occidental Energy Marketing Inc [Member]
Consolidated oil, NGL and gas revenues represented by the company's purchases	14.00%	8.00%	7.00%
Enterprise Products Partners L.P. [Member]
Consolidated oil, NGL and gas revenues represented by the company's purchases	12.00%	10.00%	6.00%