Derivative Financial Instruments (Summary of recognized gains (losses) related to derivative financial instruments) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Recognized Gains (Losses)
Derivative instruments not designated as hedging instruments, gain (loss), net	$ 2	$ (1)
Gain (loss) on derivative instruments, net, pretax	2
Currency forwards [Member]
Recognized Gains (Losses)
Derivative instruments not designated as hedging instruments, gain (loss), net	2	(1)
Futures sold, not yet purchased [Member]
Recognized Gains (Losses)
Gain (loss) on derivative instruments held for trading purposes, net		$ 1

Aggregate net gain and losses (whether realized or unrealized) on all derivative instruments held for trading purposes whether or not settled physically.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 45

-Paragraph 9

-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41322-113958

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 815

-SubTopic 10

-Section 50

-Paragraph 4F

-URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5624186-113959

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

-Publisher FASB

-Name Emerging Issues Task Force (EITF)

-Number 02-3

-Paragraph 8

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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