Non-Hedge Derivative Gain (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
Jun. 30, 2012	Jun. 30, 2011
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net [Abstract]
Gain/(loss) on non-hedge derivatives	$ 67	$ 88
Fair Value Disclosures, Movement on Bonds [Abstract]
Fair value gain/(loss) on mandatory convertible bonds	$ 113	$ 92

Net gain (loss) from the increase (decrease) in fair value of derivative instrument not designated as hedging instrument.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 133

-Paragraph 45

-Subparagraph b(1)(b)

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 4C

-Subparagraph (e)

-URI http://asc.fasb.org/extlink&oid=6935481&loc=SL5624171-113959

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