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Suspended Wells (Details) (USD $) In Millions, unless otherwise specified | 6 Months Ended |
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Jun. 30, 2013 | Dec. 31, 2012
Suspended Wells (Textual) [Abstract] |  |
Capitalized cost of suspended wells | $ 915 | $ 1,038
Increase (decrease) in capitalized cost of suspended wells | $ (123) |

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- Definition The change during the reporting period in capitalized exploratory well costs. This change comprises additions of capitalized costs where proven reserves have not been found, reclassification of capitalized costs where proved reserves were found, and capitalized costs that were expensed when proved reserves were definitively not found. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS19-1 -Paragraph 10 -Subparagraph a -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 1B -Subparagraph a -URI http://asc.fasb.org/extlink&oid=8451039&loc=SL6806780-109447 + Details
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- Definition The amount of capitalized exploratory well costs that is pending the determination of proved reserves. This does not include amounts that were capitalized and subsequently expensed in the same annual period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 932 -SubTopic 235 -Section 50 -Paragraph 1B -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=8451039&loc=SL6806780-109447 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS19-1 -Paragraph 10 -Subparagraph a -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
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