Postretirement Plans (Schedule Of Actuarial Assumptions Used To Determine Net Periodic Benefit Cost) (Details)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Qualified Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.75%	5.50%	5.875%
Expected long-term rate of return on assets	8.00%	8.50%	8.50%
Rate of increase in future compensation levels	4.30%	4.40%	4.50%
Retiree Medical And Life Insurance Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.50%	5.50%	5.875%
Expected long-term rate of return on assets	8.00%	8.50%	8.50%
Health care cost trend rate assumed for next year	9.50%	10.00%
Ultimate trend rate	5.00%	5.00%
Year that the ultimate trend rate is reached	2021	2021