Derivative Instruments, Fair Value Derivatives Designated as Hedging Instruments (Details) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Derivatives designated as hedging instruments [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Total	$ 31	$ 142
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Total	315	127
Derivatives designated as hedging instruments [Member] \| Interest Rate Swap [Member] \| Current derivative assets [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Asset	19	16
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Asset	0	0
Derivatives designated as hedging instruments [Member] \| Interest Rate Swap [Member] \| Current derivative liabilities [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Liability	0	0
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Liability	58	64
Derivatives designated as hedging instruments [Member] \| Interest Rate Swap [Member] \| Noncurrent derivative assets [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Asset	12	91
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Asset	0	0
Derivatives designated as hedging instruments [Member] \| Interest Rate Swap [Member] \| Noncurrent derivative liabilities [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Liability	0	0
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Liability	249	59
Derivatives designated as hedging instruments [Member] \| Foreign currency swaps [Member] \| Current derivative assets [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Asset	0	24
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Asset	0	0
Derivatives designated as hedging instruments [Member] \| Foreign currency swaps [Member] \| Current derivative liabilities [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Liability	0	0
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Liability	2	4
Derivatives designated as hedging instruments [Member] \| Foreign currency swaps [Member] \| Noncurrent derivative assets [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Asset	0	11
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Asset	0	0
Derivatives designated as hedging instruments [Member] \| Foreign currency swaps [Member] \| Noncurrent derivative liabilities [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Asset	0	0
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Asset	6	0
Derivatives not designated as hedging instruments [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Total	3,903	4,130
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Total	3,908	3,858
Derivatives not designated as hedging instruments [Member] \| Foreign currency swaps [Member] \| Current derivative assets [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Asset	0	13
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Asset	0	0
Derivatives not designated as hedging instruments [Member] \| Foreign currency swaps [Member] \| Current derivative liabilities [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Liability	0	0
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Liability	2	0
Derivatives not designated as hedging instruments [Member] \| Foreign currency swaps [Member] \| Noncurrent derivative assets [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Liability	23	0
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Liability	0	0
Derivatives not designated as hedging instruments [Member] \| Commodity contracts [Member] \| Current derivative assets [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Asset	667	754
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Asset	316	278
Derivatives not designated as hedging instruments [Member] \| Commodity contracts [Member] \| Current derivative liabilities [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Liability	1,815	1,848
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Liability	2,412	2,339
Derivatives not designated as hedging instruments [Member] \| Commodity contracts [Member] \| Noncurrent derivative assets [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Asset	651	687
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Asset	133	157
Derivatives not designated as hedging instruments [Member] \| Commodity contracts [Member] \| Noncurrent derivative liabilities [Member]
Derivative Asset, Fair Value [Abstract]
Derivative Asset, Gross Liability	747	828
Derivative Liability, Fair Value [Abstract]
Derivative Liability, Gross Liability	$ 1,045	$ 1,084

Fair value of liability associated with derivative asset, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4B

-Subparagraph (a),(c)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624163-113959

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 44C

-Subparagraph a

-Clause 1

-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 133

-Paragraph 205G

-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.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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- Definition

Fair value as of the balance sheet date of the gross assets less the gross liabilities of a derivative asset or group of derivative assets.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 15

-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13495-108611

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 5

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41228-113958

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 825

-SubTopic 10

-Section 50

-Paragraph 10

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=6947722&loc=d3e13433-108611

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- Definition

Fair value of derivative asset, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

+ References

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- Definition

Fair value of derivative liability, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position.

+ References

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- Definition

+ References

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Data Type:	xbrli:monetaryItemType
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- Definition

Fair value as of the balance sheet date of the gross assets less the gross liabilities of a derivative liability or group of derivative liabilities.

+ References

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