Postretirement Plans (Schedule Of Key Information For All Plans With ABO In Excess Of Plan Assets) (Details) - Pension Plans [Member] - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Accumulated Benefit Obligation	$ 70,466	$ 66,306
Defined Benefit Plan, Plan with Accumulated Benefit Obligation in Excess of Plan Assets, Plan Assets	55,907	52,894
Projected benefit obligation	72,325	68,354
Defined Benefit Plan, Pension Plan with Projected Benefit Obligation in Excess of Plan Assets, Plan Assets	$ 55,907	$ 52,894