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Pension and Other Postretirement Benefits (Schedule Of Pension Plan And Postretirement Plan Asset Mix) (Details) - USD ($) $ in Millions | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | --- | ---
Fair Value, Inputs, Level 1, 2 and 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 2,275.4 | $ 2,404.1 |
Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage of total asset | 100.00% | 100.00% |
Pension Plan | Fair Value, Inputs, Level 1, 2 and 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 1,981.7 | $ 2,117.7 | $ 2,080.9
Other Postretirement Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage of total asset | 100.00% | 100.00% |
Other Postretirement Benefits | Fair Value, Inputs, Level 1, 2 and 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 293.7 | $ 286.4 | $ 261.4
Domestic Equities | Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 324.3 | $ 446.3 |
Percentage of total asset | 16.40% | 21.00% |
Domestic Equities | Other Postretirement Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 118.6 | $ 108.8 |
Percentage of total asset | 40.40% | 38.00% |
International Equities | Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 150.9 | $ 230.1 |
Percentage of total asset | 7.60% | 10.90% |
International Equities | Other Postretirement Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 50.5 | $ 48.2 |
Percentage of total asset | 17.20% | 16.80% |
Fixed Income | Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 1,382.3 | $ 1,291.2 |
Percentage of total asset | 69.70% | 61.00% |
Fixed Income | Other Postretirement Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 118.8 | $ 122.0 |
Percentage of total asset | 40.40% | 42.60% |
Real Estate | Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 37.2 | $ 52.9 |
Percentage of total asset | 1.90% | 2.50% |
Real Estate | Other Postretirement Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 0.0 | $ 0.0 |
Percentage of total asset | 0.00% | 0.00% |
Cash/Other [Member] | Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 87.0 | $ 97.2 |
Percentage of total asset | 4.40% | 4.60% |
Cash/Other [Member] | Other Postretirement Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 5.8 | $ 7.4 |
Percentage of total asset | 2.00% | 2.60% |
Commingled Funds | Short-Term Money Markets | Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 55.0 | $ 78.8 |
Commingled Funds | Short-Term Money Markets | Other Postretirement Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 5.8 | 7.6 |
Commingled Funds | International Equities | Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 111.7 | 176.8 |
Commingled Funds | International Equities | Other Postretirement Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 26.1 | 24.1 |
Commingled Funds | Fixed Income | Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 349.1 | 337.6 |
Commingled Funds | United States Equities | Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | 195.9 | 279.7 |
Commingled Funds | United States Equities | Other Postretirement Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Plan Assets, Amount | $ 14.8 | $ 14.0 |

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