Employee Benefit Plans (Medicare Part D Subsidy) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012
Disclosure of Expected Gross Prescription Drug Subsidy Receipts [Abstract]
2013	$ 4
2014	4
2015	4
2016	4
2017	5
2018-2022	24
Total	$ 45

Prescription drug subsidy receipts, net.

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- Definition

Amount of the prescription drug subsidy receipts to be received after the fifth fiscal year following the latest fiscal year.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 60

-Section 50

-Paragraph 4

-URI http://asc.fasb.org/extlink&oid=6414203&loc=d3e39716-114964

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=21915506&loc=d3e1928-114920

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Amount of the prescription drug subsidy receipts to be received in the next fiscal year following the latest fiscal year.

+ References

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Amount of the prescription drug subsidy receipts to be received in the fifth fiscal year following the latest fiscal year.

+ References

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Amount of the prescription drug subsidy receipts to be received in the fourth fiscal year following the latest fiscal year.

+ References

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Amount of the prescription drug subsidy receipts to be received in the third fiscal year following the latest fiscal year.

+ References

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Amount of the prescription drug subsidy receipts to be received in the second fiscal year following the latest fiscal year.

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