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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 |

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