Other Postretirement Benefits (Expected Benefit Payments) (Details) (Other Postretirement Benefits [Member], USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Other Postretirement Benefits [Member]
Schedule Of Other Postretirement Benefits [Line Items]
2012	$ 122
2013	124
2014	126
2015	128
2016	128
2017-2021	640
2012 - Prescriptions	12
2013 - Prescriptions	13
2014 - Prescriptions	14
2015 - Prescriptions	15
2016 - Prescriptions	16
2017-2021 - Prescriptions	$ 94

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The amount of the aggregate benefits expected to be paid in the five fiscal years thereafter (the aggregate amount of benefits expected to be paid in years 6 through 10 after the date of the latest statement of financial position).

+ References

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph f

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

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- Definition

The amount of the benefits expected to be paid in Year 5.

+ References

+ Details

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- Definition

The amount of the benefits expected to be paid in Year 4.

+ References

+ Details

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- Definition

The amount of the benefits expected to be paid in Year 1.

+ References

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- Definition

The amount of the benefits expected to be paid in Year 3.

+ References

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- Definition

The amount of the benefits expected to be paid in Year 2.

+ References

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- Definition

Aggregate amount for the next five fiscal years following the first five fiscal years (that is the aggregate of fiscal years six through ten) following the balance sheet date of the prescription drug subsidy receipts expected to be received.

+ 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 Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph f

-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 FASB Staff Position (FSP)

-Number FAS106-2

-Paragraph 22

-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 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (f)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e1928-114920

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- Definition

Amount of the prescription drug subsidy receipts expected to be received in Year 5 after the balance sheet date.

+ References

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- Definition

Amount of the prescription drug subsidy receipts expected to be received in Year 4 after the balance sheet date.

+ References

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- Definition

Amount of the prescription drug subsidy receipts expected to be received in Year 1 after the balance sheet date.

+ References

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- Definition

Amount of the prescription drug subsidy receipts expected to be received in Year 3 after the balance sheet date.

+ References

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- Definition

Amount of the prescription drug subsidy receipts expected to be received in Year 2 after the balance sheet date.

+ References

+ Details

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