Employee Benefit Plans (Schedule Of Assumptions Used) (Details)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Employee Benefit Plans [Abstract]
Annual increase in cost of benefits	5.80%	5.90%	7.00%
Discount rate used to determine year-end obligations	3.30%	3.30%	4.50%
Discount rate used to determine year-end expense	3.30%	4.50%	4.50%