Pension and Other Postretirement Benefits (Details 2)	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010
Pension Benefits [Member]
Weighted average assumptions for benefit obligations at year end:
Discount rate	4.50%	5.10%
Salary increase	3.90%	4.00%
Weighted average assumptions for net periodic cost for the year:
Discount rate	5.10%	5.40%
Salary increase	4.00%	4.00%
Expected return on assets	7.40%	7.50%
Other Benefits [Member]
Weighted average assumptions for benefit obligations at year end:
Discount rate	4.30%	5.20%
Weighted average assumptions for net periodic cost for the year:
Discount rate	5.20%	5.30%
Assumed health care cost trend rates:
Health care cost trend rate assumed for next year	8.00%	8.20%
Rate that the cost trend rate gradually declines to	5.00%	5.00%
Year that the rate reaches the rate it is assumed to remain at	2020	2017

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

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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.

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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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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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