Retirement Benefits (Details 8)	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010
Pension Benefits
Assumptions Used to Determine Benefit Obligation at December 31 [Abstract]
Discount rate	5.03%	5.75%
Benefit Obligation \| Pension Benefits
Assumptions Used to Determine Benefit Obligation at December 31 [Abstract]
Discount rate	5.03%	5.75%
Rate of compensation increase	2.75%	3.50%
Benefit Obligation \| Medical and Life Benefits
Assumptions Used to Determine Benefit Obligation at December 31 [Abstract]
Discount rate	5.02%	5.62%
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2017	2017
Initial health care cost trend rate assumed for the next year	7.50%	8.00%
Benefit Cost \| Pension Benefits
Assumptions Used to Determine Benefit Obligation at December 31 [Abstract]
Discount rate	5.75%	6.03%
Expected long-term return on plan assets	8.50%	8.50%
Rate of compensation increase	3.50%	3.75%
Benefit Cost \| Medical and Life Benefits
Assumptions Used to Determine Benefit Obligation at December 31 [Abstract]
Rate to which the cost trend rate is assumed to decline (the ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2017	2014
Discount rate	5.62%	5.77%
Expected long-term return on plan assets	6.86%	6.90%
Initial health care cost trend rate assumed for the next year	8.00%	7.00%

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

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-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 132R

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

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

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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

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

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

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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.

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-Glossary Health Care Cost Trend Rate

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The ultimate trend rate for health care costs.

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The year when the ultimate health care cost trend rate is expected to be reached.

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