Benefit Plans (Assumptions Used) (Details)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pension Benefits [Member]
Weighted average assumptions used in net periodic benefit cost:
Discount rate	4.78%	5.55%	5.92%
Rate of compensation increase	4.29%	4.33%	4.36%
Long-term rate of return on assets	7.37%	7.59%	7.60%
Weighted average assumptions used in benefit obligations:
Discount rate	4.07%	4.87%
Rate of compensation increase	4.39%	4.33%
Other Retirement Benefits [Member]
Weighted average assumptions used in net periodic benefit cost:
Discount rate	4.50%	5.25%	5.25%
Rate of compensation increase	0.00%	0.00%	0.00%
Long-term rate of return on assets	0.00%	0.00%	0.00%
Weighted average assumptions used in benefit obligations:
Discount rate	3.50%	4.50%
Rate of compensation increase	0.00%	0.00%