Property, Plant & Equipment (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Components of Property, plant and equipment
Unproved properties	$ 4,064	$ 3,796
Proved properties	3,975	3,496
Wells, equipment and related facilities	29,239	26,064
Total Exploration and Production costs	37,278	33,356
Marketing, Refining and Corporate	2,432	2,347
Total - at cost	39,710	35,703
Less reserves for depreciation, depletion, amortization and lease impairment	14,998	14,576
Property, plant and equipment - net	$ 24,712	$ 21,127	$ 16,627

The cumulative amount of depreciation, depletion and amortization (related to property, plant and equipment, but not including land) that has been recognized in the income statement.

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Capitalized costs which include those incurred to (1) to drill and equip those exploratory wells and exploratory-type stratigraphic test wells that have found proved reserves and (2) obtain access to proved reserves and provide facilities for extracting, treating, gathering, storing the oil and gas, including the drilling and equipping of development wells and development-type stratigraphic wells and service wells.

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- Definition

Gross amount, at the balance sheet date, of long-lived physical assets used in the normal conduct of business and not intended for resale. This can include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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- Definition

Tangible assets that are held by an entity for use in the production or supply of goods and services, for rental to others, or for administrative purposes and that are expected to provide economic benefit for more than one year; net of accumulated depreciation. Examples include land, buildings, machinery and equipment, and other types of furniture and equipment including, but not limited to, office equipment, furniture and fixtures, and computer equipment and software.

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- Definition

Oil and Gas properties with unproved reserves under the successful effort method.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Unproved Properties

-URI http://asc.fasb.org/extlink&oid=6527831

-Topic 932

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 19

-Paragraph 59N

-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 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 19

-Paragraph 11

-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 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 19

-Paragraph 147, 148

-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 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 235

-Section 50

-Paragraph 14

-URI http://asc.fasb.org/extlink&oid=6821537&loc=d3e61926-109447

Reference 6: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 932

-SubTopic 360

-Section 25

-Paragraph 3

-URI http://asc.fasb.org/extlink&oid=6474861&loc=d3e64746-109465

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