Organization And Basis Of Presentation (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012
East Texas/North Louisiana JV [Member]
Percentage of ownership interest	50.00%
TGGT Holdings, LLC [Member]
Percentage of ownership interest	50.00%
Appalachia Midstream JV [Member]
Percentage of ownership interest	50.00%
Appalachia JV [Member]
Percentage of ownership interest	50.00%
Carry commitment percentage	75.00%
Proportional interest	49.75%
Remaining Carry balance	$ 29.7
Working interest in equity investment	0.50%
Deep drilling and completion costs	$ 150.0
Midstream [Member]
Percentage of ownership interest	50.00%
Midstream [Member] | East Texas North, Louisiana And Appalachia [Member]
Percentage of ownership interest	50.00%