Postretirement Benefit Plans (Details 8)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011
Equity securities
Defined Benefit Plan Disclosure
Actual allocation of plan assets	29.20%	42.20%
Minimum target allocation	20.00%
Maximum target allocation	40.00%
Fixed income
Defined Benefit Plan Disclosure
Actual allocation of plan assets	26.40%	41.50%
Minimum target allocation	20.00%
Maximum target allocation	50.00%
Hedge funds
Defined Benefit Plan Disclosure
Actual allocation of plan assets	29.40%	8.90%
Minimum target allocation	20.00%
Maximum target allocation	60.00%
Private equity
Defined Benefit Plan Disclosure
Actual allocation of plan assets	5.10%	5.80%
Minimum target allocation	0.00%
Maximum target allocation	15.00%
Cash and other
Defined Benefit Plan Disclosure
Actual allocation of plan assets	9.90%	1.60%
Minimum target allocation	0.00%
Maximum target allocation	30.00%

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Target allocation maximum percentage of investments of this type to total plan assets presented on a weighted average basis.

+ References

Reference 1: 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=21915506&loc=d3e1928-114920

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=21915506&loc=d3e2446-114920

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- Definition

Target allocation minimum percentage of investments of this type to total plan assets presented on a weighted average basis.

+ References

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- Definition

Percentage of fair value of investments (categorized by debt securities, equity securities, real estate and other plan assets) to the fair value of plan assets held.

+ References

Reference 1: 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=21915506&loc=d3e2446-114920

Reference 2: 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=21915506&loc=d3e1928-114920

Reference 3: 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.

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