Pension and Other Postretirement Benefit Plans - Weighted-Average Assumptions Used to Determine Benefit Obligation and Net Periodic Benefit Costs (Details)	12 Months Ended
Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pension [Member]
Weighted-Average Assumptions Used to Determine Benefit Obligation [Abstract]
Discount Rate	4.10%	4.54%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Costs [Abstract]
Discount Rate	4.54%	5.36%	5.81%
Expected Long-term Return on Plan Assets	8.25%	8.50%	8.50%
Pension [Member] \| Minimum [Member]
Weighted-Average Assumptions Used to Determine Benefit Obligation [Abstract]
Rate of Compensation Increase	4.30%	4.30%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Costs [Abstract]
Rate of Compensation Increase	4.30%	4.30%	4.30%
Pension [Member] \| Maximum [Member]
Weighted-Average Assumptions Used to Determine Benefit Obligation [Abstract]
Rate of Compensation Increase	4.60%	4.60%
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Costs [Abstract]
Rate of Compensation Increase	4.60%	4.60%	4.60%
Postretirement Health and Life [Member]
Weighted-Average Assumptions Used to Determine Benefit Obligation [Abstract]
Discount Rate	4.13%	4.56%
Trend Rate	9.25%	10.00%
Ultimate Trend Rate	5.00%	5.00%
Year Ultimate Trend Rate Effective	2019	2018
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Costs [Abstract]
Discount Rate	4.56%	5.40%	5.81%
Postretirement Health and Life [Member] \| Minimum [Member]
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Costs [Abstract]
Expected Long-term Return on Plan Assets	6.60%	6.80%	6.80%
Postretirement Health and Life [Member] \| Maximum [Member]
Weighted-Average Assumptions Used to Determine Net Periodic Benefit Costs [Abstract]
Expected Long-term Return on Plan Assets	8.25%	8.50%	8.50%

The interest rate used to adjust for the time value of money for the plan.

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

-Paragraph 5

-Subparagraph j

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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 (k)(1)

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

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- Definition

Expected rate of compensation increases (for pay-related plans).

+ References

+ Details

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Period Type:	instant

- Definition

The interest rate used to adjust for the time value of money.

+ References

+ Details

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Period Type:	duration

- Definition

An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation.

+ 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 (k)(3)

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

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

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 87

-Paragraph 264

-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 132R

-Paragraph 5

-Subparagraph j

-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 30

-Glossary Expected Long-Term Rate of Return on Plan Assets

-URI http://asc.fasb.org/extlink&oid=6512013

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- Definition

Expected rate of compensation increases (for pay-related plans).

+ References

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- Definition

The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.

+ References

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- Definition

The ultimate trend rate for health care costs.

+ References

+ Details

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- Definition

Year the ultimate health care cost trend rate is expected to be reached, in CCYY format.

+ References

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