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Retirement Benefits (Schedule Of Allocation Of Plan Assets) (Details) - USD ($) $ in Millions | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | --- | ---
DB Pension Plans |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | $ 3,599 | $ 3,402 | $ 2,546
DB Pension Plans | Plan Assets Excluding Pooled Funds |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 1,698 | 1,828 |
DB Pension Plans | Plan Assets Excluding Pooled Funds | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 815 | 1,086 |
DB Pension Plans | Plan Assets Excluding Pooled Funds | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 883 | 742 |
DB Pension Plans | Cash and short-term investments |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 30 | 115 |
DB Pension Plans | Cash and short-term investments | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 30 | 115 |
DB Pension Plans | U.S. government and agencies securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 209 | 150 |
DB Pension Plans | U.S. government and agencies securities | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 209 | 150 |
DB Pension Plans | Corporate debt |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 595 | 540 |
DB Pension Plans | Corporate debt | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 595 | 540 |
DB Pension Plans | State and municipal bonds |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 13 | 11 |
DB Pension Plans | State and municipal bonds | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 13 | 11 |
DB Pension Plans | Foreign corporate bonds |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 66 | 41 |
DB Pension Plans | Foreign corporate bonds | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 66 | 41 |
DB Pension Plans | Mutual funds |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 785 | 971 |
DB Pension Plans | Mutual funds | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 785 | 971 |
DB Pension Plans | Pooled funds |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 1,901 | 1,574 |
OPEB Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 1,787 | 1,645 | $ 1,509
OPEB Plan | Plan Assets Excluding Pooled Funds |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 1,155 | 995 |
OPEB Plan | Plan Assets Excluding Pooled Funds | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 1,047 | 906 |
OPEB Plan | Plan Assets Excluding Pooled Funds | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 108 | 89 |
OPEB Plan | Cash and short-term investments |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 21 | 33 |
OPEB Plan | Cash and short-term investments | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 21 | 33 |
OPEB Plan | U.S. government and agencies securities |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 25 | 18 |
OPEB Plan | U.S. government and agencies securities | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 25 | 18 |
OPEB Plan | Corporate debt |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 73 | 64 |
OPEB Plan | Corporate debt | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 73 | 64 |
OPEB Plan | State and municipal bonds |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 2 | 2 |
OPEB Plan | State and municipal bonds | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 2 | 2 |
OPEB Plan | Foreign corporate bonds |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 8 | 5 |
OPEB Plan | Foreign corporate bonds | Level 2 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 8 | 5 |
OPEB Plan | Common stocks |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 85 | 66 |
OPEB Plan | Common stocks | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 85 | 66 |
OPEB Plan | Mutual funds |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 941 | 807 |
OPEB Plan | Mutual funds | Level 1 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | 941 | 807 |
OPEB Plan | Pooled funds |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Plan assets | $ 632 | $ 650 |

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