Retirement Benefits (Schedule Of Accumulated And Projected Benefit Obligations) (Details) - DB Pension Plans - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
PBO	$ 2,973	$ 2,512	$ 2,780
ABO	2,600	2,200
Fair value of plan assets	2,546	2,247	$ 2,305
Pension Plan A
Defined Benefit Plan Disclosure [Line Items]
PBO	1,736	1,363
ABO	1,398	1,091
Fair value of plan assets	$ 1,205	$ 1,059