Employee Benefits Schedule of Allocation of Plan Assets (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Actual [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity Securities	68.00%	68.00%
Debt Securities	32.00%	32.00%
defined benefit pension plan asset allocation	100.00%	100.00%
Actual [Member] | Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity Securities	63.00%	61.00%
Debt Securities	37.00%	39.00%
defined benefit pension plan asset allocation	100.00%	100.00%
Actual [Member] | Non Qualified Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity Securities	17.00%	30.00%
Debt Securities	6.00%	7.00%
defined benefit pension plan asset allocation	100.00%	100.00%
Insurance contracts	77.00%	63.00%
Target [Member] | Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity Securities	67.00%	67.00%
Debt Securities	33.00%	33.00%
defined benefit pension plan asset allocation	100.00%	100.00%
Target [Member] | Other Postretirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity Securities	72.00%	72.00%
Debt Securities	28.00%	28.00%
defined benefit pension plan asset allocation	100.00%	100.00%
Target [Member] | Non Qualified Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Equity Securities	17.00%	23.00%
Debt Securities	10.00%	14.00%
defined benefit pension plan asset allocation	100.00%	100.00%
Insurance contracts	73.00%	63.00%