Retirement Benefits (Target Allocation Of The Plans' Asset Categories) (Details)	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010
Pension Benefits [Member]
Percentage of Plan Assets, Total	100.00%	100.00%
Pension Benefits [Member] \| Cash And Cash Equivalents [Member]
Minimum Target Allocation	0.00%
Maximum Target Allocation	5.00%
Percentage of Plan Assets, Other	2.00%	1.00%
Pension Benefits [Member] \| Equity Securities [Member]
Minimum Target Allocation, Equity securities	50.00%
Maximum Target Allocation, Equity securities	60.00%
Percentage of Plan Assets, Equity securities	51.00%	57.00%
Pension Benefits [Member] \| U.S. Large Capitalization [Member]
Minimum Target Allocation, Equity securities	29.00%
Maximum Target Allocation, Equity securities	39.00%
Percentage of Plan Assets, Equity securities	33.00%	31.00%
Pension Benefits [Member] \| U.S. Small And Mid Capitalization [Member]
Minimum Target Allocation, Equity securities	2.00%
Maximum Target Allocation, Equity securities	12.00%
Percentage of Plan Assets, Equity securities	7.00%	11.00%
Pension Benefits [Member] \| International And Emerging Markets [Member]
Minimum Target Allocation, Equity securities	9.00%
Maximum Target Allocation, Equity securities	19.00%
Percentage of Plan Assets, Equity securities	11.00%	15.00%
Pension Benefits [Member] \| Debt Securities [Member]
Minimum Target Allocation, Debt securities	35.00%
Maximum Target Allocation, Debt securities	45.00%
Percentage of Plan Assets, Debt securities	42.00%	37.00%
Pension Benefits [Member] \| Real Estate [Member]
Minimum Target Allocation, Real estate	0.00%
Maximum Target Allocation, Real estate	9.00%
Percentage of Plan Assets, Real estate	4.00%	4.00%
Pension Benefits [Member] \| Private Equity [Member]
Maximum Target Allocation	4.00%
Percentage of Plan Assets, Other	1.00%	1.00%
Postretirement Benefits [Member]
Percentage of Plan Assets, Total	100.00%	100.00%
Postretirement Benefits [Member] \| Cash And Cash Equivalents [Member]
Minimum Target Allocation	0.00%
Maximum Target Allocation	10.00%
Percentage of Plan Assets, Other	4.00%	4.00%
Postretirement Benefits [Member] \| Equity Securities [Member]
Minimum Target Allocation, Equity securities	55.00%
Maximum Target Allocation, Equity securities	65.00%
Percentage of Plan Assets, Equity securities	59.00%	63.00%
Postretirement Benefits [Member] \| U.S. Large Capitalization [Member]
Minimum Target Allocation, Equity securities	33.00%
Maximum Target Allocation, Equity securities	43.00%
Percentage of Plan Assets, Equity securities	38.00%	39.00%
Postretirement Benefits [Member] \| U.S. Small And Mid Capitalization [Member]
Minimum Target Allocation, Equity securities	3.00%
Maximum Target Allocation, Equity securities	13.00%
Percentage of Plan Assets, Equity securities	8.00%	10.00%
Postretirement Benefits [Member] \| International [Member]
Minimum Target Allocation, Equity securities	10.00%
Maximum Target Allocation, Equity securities	20.00%
Percentage of Plan Assets, Equity securities	13.00%	14.00%
Postretirement Benefits [Member] \| Debt Securities [Member]
Minimum Target Allocation, Debt securities	30.00%
Maximum Target Allocation, Debt securities	40.00%
Percentage of Plan Assets, Debt securities	37.00%	33.00%
Postretirement Benefits [Member] \| Private Equity [Member]
Minimum Target Allocation	0.00%

The percentage of the fair value of debt securities to the fair value of total plan assets held as of the measurement date.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph d(1)

-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 5

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e2446-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(1)

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

+ Details

Name:	us-gaap_DefinedBenefitPlanDebtSecurities
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of the fair value of equity securities to the fair value of total plan assets held as of the measurement date.

+ References

+ Details

Name:	us-gaap_DefinedBenefitPlanEquitySecurities
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of the fair value of investments other than debt securities, equity securities, and real estate to the fair value of total plan assets held as of the measurement date.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The percentage of the fair value of real estate to the fair value of total plan assets held as of the measurement date.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Target allocation maximum percentage of investments in debt securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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- Definition

Target allocation minimum percentage of investments in debt securities to total plan assets presented on a weighted-average basis as of the measurement 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 d(2)

-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 5

-Subparagraph (c)(i)

-URI http://asc.fasb.org/extlink&oid=6962843&loc=d3e2446-114920

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 715

-SubTopic 20

-Section 50

-Paragraph 1

-Subparagraph (d)(i)

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

+ Details

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- Definition

Target allocation maximum percentage of investments in equity securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

+ References

No definition available.

+ Details

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- Definition

Target allocation minimum percentage of investments in equity securities to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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- Definition

Target allocation maximum percentage in other than debt securities, equity securities, and real estate to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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- Definition

Target allocation minimum percentage in other than debt securities, equity securities, and real estate to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Target allocation maximum percentage of investments in real estate to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Target allocation minimum percentage of investments in real estate to total plan assets presented on a weighted-average basis as of the measurement date of the latest statement of financial position.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The aggregate percentage of the fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of total plan assets held as of the measurement date.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant