Retirement Benefits (Schedule Of Accumulated And Projected Benefit Obligations) (Details) - DB Pension Plans - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
PBO	$ 3,266	$ 2,973	$ 2,512
ABO	2,900	2,600
Fair value of plan assets	$ 3,402	2,546	$ 2,247
Pension Plan A
Defined Benefit Plan Disclosure [Line Items]
PBO		1,736
ABO		1,398
Fair value of plan assets		$ 1,205