Other Postretirement Benefits (Actuarial Assumptions) (Details) (Other Postretirement Benefits [Member])	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Other Postretirement Benefits [Member]
Schedule Of Other Postretirement Benefits [Line Items]
Discount rate, benefit obligations	4.55%	5.40%	5.95%
Discount rate, net periodic benefit	5.40%	5.95%	5.75%
Expected return on plan assets	8.50%	8.50%	8.50%