Benefit Plans (Schedule of Assumptions Used) (Details)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	5.04%
Rate of compensation increase	5.22%	5.22%
Minimum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Rate of compensation increase	3.75%	3.75%	3.75%
Maximum [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Rate of compensation increase	5.22%	5.22%	5.22%
Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	5.04%	5.60%	5.98%
Long-term rate of return on assets	7.25%	8.25%	8.50%
Pension Benefits [Member] | Medical Trend Rates, Non-Medicare Risk, Under Age 65, Percent [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical trend rates
Pension Benefits [Member] | Medical Trend Rates, Non-Medicare Risk, After Age 65, Percent [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical trend rates
Pension Benefits [Member] | Prescription Drugs [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical trend rates
Postretirement Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.23%	4.43%	4.94%
Long-term rate of return on assets
Rate of compensation increase
Postretirement Benefits [Member] | Minimum [Member] | Medical Trend Rates, Non-Medicare Risk, Under Age 65, Percent [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical trend rates	8.50%	9.00%	7.00%
Postretirement Benefits [Member] | Minimum [Member] | Medical Trend Rates, Non-Medicare Risk, After Age 65, Percent [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical trend rates	12.50%	13.00%	9.00%
Postretirement Benefits [Member] | Minimum [Member] | Prescription Drugs [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical trend rates	8.50%	9.00%	9.00%
Postretirement Benefits [Member] | Minimum [Member] | Medical Trend Rates, Medicare Risk HMO, After Age 65, Percent [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical trend rates	12.50%	13.00%	9.00%
Postretirement Benefits [Member] | Maximum [Member] | Medical Trend Rates, Non-Medicare Risk, Under Age 65, Percent [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical trend rates	5.00%	5.00%	5.00%
Postretirement Benefits [Member] | Maximum [Member] | Medical Trend Rates, Non-Medicare Risk, After Age 65, Percent [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical trend rates	5.00%	5.00%	5.00%
Postretirement Benefits [Member] | Maximum [Member] | Prescription Drugs [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical trend rates	5.00%	5.00%	5.00%
Postretirement Benefits [Member] | Maximum [Member] | Medical Trend Rates, Medicare Risk HMO, After Age 65, Percent [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Medical trend rates	5.00%	5.00%	5.00%