Retirement, Other Postretirement Benefits, and Defined Contribution Plans (Details 7)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Actuarial Assumptions Used in Determining Net Periodic Pension and Other Postretirement Benefit Costs
Weighted-average rate of increase in future compensation levels	4.23%	4.23%	4.23%
Taxable [Member]
Actuarial Assumptions Used in Determining Net Periodic Pension and Other Postretirement Benefit Costs
Expected long-term rate of return on plan assets:	5.50%	5.50%	6.00%
Non - Taxable [Member]
Actuarial Assumptions Used in Determining Net Periodic Pension and Other Postretirement Benefit Costs
Expected long-term rate of return on plan assets:	7.75%	7.75%	8.50%
Pension Assets [Member]
Actuarial Assumptions Used in Determining Net Periodic Pension and Other Postretirement Benefit Costs
Expected long-term rate of return on plan assets:	8.50%	8.50%	8.50%
Qualified Pension [Member]
Actuarial Assumptions Used in Determining Net Periodic Pension and Other Postretirement Benefit Costs
Weighted-average discount rate:			6.75%
Qualified Pension [Member] | Maximum [Member]
Actuarial Assumptions Used in Determining Net Periodic Pension and Other Postretirement Benefit Costs
Weighted-average discount rate:	5.70%	6.30%
Qualified Pension [Member] | Minimum [Member]
Actuarial Assumptions Used in Determining Net Periodic Pension and Other Postretirement Benefit Costs
Weighted-average discount rate:	5.60%	6.10%
Non Qualified Pension [Member]
Actuarial Assumptions Used in Determining Net Periodic Pension and Other Postretirement Benefit Costs
Weighted-average discount rate:	4.90%	5.40%	6.75%
Other Postretirement [Member]
Actuarial Assumptions Used in Determining Net Periodic Pension and Other Postretirement Benefit Costs
Weighted-average discount rate:	5.50%	6.10%	6.70%