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Inventories
12 Months Ended
Dec. 31, 2012
Disclosure Text Block [Abstract]  
Inventories

4.  Inventories

 

       The following summarizes the major classes of inventories, included in other current assets, at December 31:

millions2012 2011
Crude oil$91 $103
Natural gas 48  49
NGLs 37  59
Total$176 $211