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Retirement Benefits (Schedule Of Pooled Funds Components) (Details) | Dec. 31, 2016 | Dec. 31, 2015
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DB Pension Plan [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
U.S. equity securities | 67.00% | 62.00%
Foreign equity securities | 16.00% | 18.00%
U.S. fixed-income securities | 9.00% | 11.00%
Foreign fixed-income securities | 4.00% | 6.00%
Alternative investments | 4.00% | 3.00%
OPEB [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
U.S. equity securities | 72.00% | 58.00%
Foreign equity securities | 13.00% | 13.00%
U.S. fixed-income securities | 8.00% | 22.00%
Foreign fixed-income securities | 4.00% | 5.00%
Alternative investments | 3.00% | 2.00%

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