Pension and Other Post Retirement Benefit Plans Pension and Other Post Retirement Benefit Plans - Schedule of Plan Assets by Category (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan Disclosure [Line Items]
Actual Plan Asset Allocations	100.00%	100.00%
Target Plan Asset Allocations	100.00%	100.00%
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Actual Plan Asset Allocations	1.30%	3.20%
Target Plan Asset Allocations	3.00%	3.00%
Equity securities
Defined Benefit Plan Disclosure [Line Items]
Actual Plan Asset Allocations	53.70%	49.70%
Target Plan Asset Allocations	51.00%	51.00%
Debt securities
Defined Benefit Plan Disclosure [Line Items]
Actual Plan Asset Allocations	43.00%	45.50%
Target Plan Asset Allocations	44.00%	44.00%
Alternative investments
Defined Benefit Plan Disclosure [Line Items]
Actual Plan Asset Allocations	2.00%	1.60%
Target Plan Asset Allocations	2.00%	2.00%