Employee Benefit Plans Actuarial Assumptions (Details)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Defined Benefit Plan, Assets, Target Allocations [Abstract]
Number of members participating	800
Scenario, Plan [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Expected return on plan assets	7.25%
Scenario, Forecast [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Expected return on plan assets	7.00%
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Expected return on plan assets	7.25%	7.75%	8.00%
Pension Plans, Defined Benefit [Member] | Nonunion [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Long-term rate of increase in compensation levels	3.58%	3.58%	3.58%
Pension Plans, Defined Benefit [Member] | Union [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Long-term rate of increase in compensation levels	3.50%	3.50%	3.50%
Pension Plans, Defined Benefit [Member] | Minimum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	4.40%	5.00%	5.75%
Pension Plans, Defined Benefit [Member] | Maximum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	4.55%	5.25%	6.00%
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Expected return on plan assets	7.25%	7.75%	8.00%
Defined Benefit Plan, Assumed Health Care Cost Trend Rates [Abstract]
Health care cost trend rate assumed for current year	9.00%
Health care cost trend rate decrease assumed for next fiscal year	0.25%
Ultimate health care cost trend rate	4.50%
Year that rate reaches ultimate trend rate	2029
Other Postretirement Benefit Plans, Defined Benefit [Member] | Nonunion [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Long-term rate of increase in compensation levels	3.58%	3.58%	3.58%
Other Postretirement Benefit Plans, Defined Benefit [Member] | Union [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Long-term rate of increase in compensation levels	3.50%	3.50%	3.50%
Other Postretirement Benefit Plans, Defined Benefit [Member] | Minimum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	3.50%	4.00%	4.75%
Other Postretirement Benefit Plans, Defined Benefit [Member] | Maximum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate	4.30%	5.00%	6.00%