v2.4.0.6
Suspended Wells (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2013
Dec. 31, 2012
Suspended Wells (Textual) [Abstract]    
Capitalized cost of suspended wells $ 1,239 $ 1,038
Increase (decrease) in capitalized cost of suspended wells $ 201