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Summary of Significant Accounting Policies (Tables)
12 Months Ended
Dec. 31, 2012
Summary of Significant Accounting Policies [Abstract]  
Schedule Of Property, Plant, And Equipment, Useful Lifes
Depreciation of property, plant and equipment is recorded on a straight-line basis over the following estimated useful lives:
Functional Class of Property
 
Useful Lives (Years)
Gathering and Transmission Systems
 
10 - 50
Compression Equipment
 
2 - 30
Gas Plants and Buildings
 
5 - 35
Other property, plant and equipment
 
3 - 15