Commitments and Contingencies (Schedule of Purchase Obligations) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Recorded Unconditional Purchase Obligation Payment Schedule [Abstract]
2012	$ 275
2013	165
2014	107
2015	68
2016	52
Thereafter	131
Total purchase obligations	$ 798

The carrying amount of the long-term purchase obligation as of the balance sheet date, which equals the sum of all payments due.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 6

-URI http://asc.fasb.org/extlink&oid=6394976&loc=d3e25383-109308

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 47

-Paragraph 6

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 47

-Paragraph 10

-Subparagraph 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 4: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 440

-SubTopic 10

-Section 50

-Paragraph 2

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- Definition

The aggregate remaining amount of payments due after the fifth year after the balance sheet date to extinguish a recorded unconditional purchase obligation.

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 47

-Paragraph 10

-Subparagraph 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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 440

-SubTopic 10

-Section 50

-Paragraph 6

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The aggregate amount of payments due in the fifth year after the balance sheet date to reduce a recorded unconditional purchase obligation.

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The aggregate amount of payments due in the fourth year after the balance sheet date to reduce a recorded unconditional purchase obligation.

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The aggregate amount of payments due in the second year after the balance sheet date to reduce a recorded unconditional purchase obligation.

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The aggregate amount of payments due in the third year after the balance sheet date to reduce a recorded unconditional purchase obligation.

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The aggregate amount of payments due in the first year after the balance sheet date to reduce a recorded unconditional purchase obligation.

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