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Financial Instruments and Derivative Contracts - Fair Value of Derivative Contracts and Gains (losses) from Derivatives Contracts (Detail) (USD $) In Millions, unless otherwise specified | 12 Months Ended
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Dec. 31, 2011 | Dec. 31, 2010 | Dec. 31, 2009
Sales and other operating revenues [Member] |  |  |
Liabilities |  |  |
Gains (losses) from derivatives contracts | $ 907 | $ (964) | $ 1,717
Other Income [Member] |  |  |
Liabilities |  |  |
Gains (losses) from derivatives contracts | (9) | (5) | 4
Purchased commodities [Member] |  |  |
Liabilities |  |  |
Gains (losses) from derivatives contracts | (729) | 915 | (1,502)
Income from discontinued operations [Member] |  |  |
Liabilities |  |  |
Gains (losses) from derivatives contracts | (446) | (139) | (854)
Commodity Contract [Member] | Prepaid expenses and other current assets [Member] |  |  |
Assets |  |  |
Commodity derivative assets | 4,433 | 3,073 |
Commodity Contract [Member] | Other assets [Member] |  |  |
Assets |  |  |
Commodity derivative assets | 415 | 211 |
Commodity Contract [Member] | Other accruals [Member] |  |  |
Liabilities |  |  |
Commodity derivative liabilities | 4,350 | 3,212 |
Commodity Contract [Member] | Other liabilities and deferred credits [Member] |  |  |
Liabilities |  |  |
Commodity derivative liabilities | $ 374 | $ 193 |

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- Definition Amount of gain (loss) recognized in earnings in the period from the increase (decrease) in fair value of price risk derivatives not designated as hedging instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (e) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624171-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 44 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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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- Definition Fair value as of the balance sheet date of all price risk derivative assets not designated as hedging instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 17 -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 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959 + Details
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- Definition Fair value as of the balance sheet date of all price risk derivative liabilities not designated as hedging instruments. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 17 -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 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624163-113959 + Details
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