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Pension and Other Postretirement Benefits (Schedule Of Reconciliation Of The Plans Funded Status And Amounts Reflected) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020
Defined Benefit Plan Disclosure [Line Items] |  |  |
Noncurrent liabilities | $ (223.1) | $ (261.5) |
COVID-19 related regulatory asset | 2,580.8 | 2,492.2 |
Regulatory Liabilities | 2,012.6 | 1,980.0 |
Unrecognized Pension Benefit And Other Postretirement Benefit Costs |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Regulatory Liabilities | 0.0 | 0.0 |
Unrecognized Pension Benefit And Other Postretirement Benefit Costs |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
COVID-19 related regulatory asset | 607.5 | 512.1 |
Fair Value, Inputs, Level 1, 2 and 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at beginning of year | 2,275.4 |  |
Fair value of plan assets at end of year | 1,647.7 | 2,275.4 |
Pension Plan |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Benefit obligation at beginning of year | 1,852.4 | 2,058.4 |
Service cost | 27.8 | 30.2 | $ 32.0
Interest cost | 40.5 | 31.4 | 51.6
Plan participants' contributions | 0.0 | 0.0 |
Plan amendments | 0.2 | 0.0 |
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) | (318.7) | (68.7) |
Defined Benefit Plan, Benefit Obligation, Benefits Paid | 174.8 | 198.9 |
Estimated benefits paid by incurred subsidy | 0.0 | 0.0 |
Projected benefit obligation at end of year | 1,427.4 | 1,852.4 | 2,058.4
Actual return on plan assets | (386.8) | 58.9 |
Employer contributions | 2.7 | 4.0 |
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant | 0.0 | 0.0 |
Benefits paid | (174.8) | (198.9) |
Defined Benefit Plan, Funded (Unfunded) Status of Plan | (4.6) | 129.3 |
Noncurrent assets | 18.3 | 159.3 |
Current liabilities | (2.6) | (2.8) |
Noncurrent liabilities | (20.3) | (27.2) |
Net amount recognized at end of year | (4.6) | 129.3 |
Unrecognized prior service cost | 0.4 | 0.3 |
Unrecognized actuarial loss | 564.2 | 438.0 |
Defined Benefit Plan Amounts Recognized In Other Comprehensive Income Or Regulatory Asset Or Liability | 564.6 | 438.3 |
Pension Plan | Underfunded Plan [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Benefit obligation at beginning of year | 1,822.4 |  |
Projected benefit obligation at end of year | 1,404.5 | 1,822.4 |
Fair value of plan assets at beginning of year | 1,981.7 |  |
Fair value of plan assets at end of year | 1,422.8 | 1,981.7 |
Defined Benefit Plan, Funded (Unfunded) Status of Plan | 18.3 | 159.3 |
Pension Plan | Fair Value, Inputs, Level 1, 2 and 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at beginning of year | 1,981.7 | 2,117.7 |
Fair value of plan assets at end of year | 1,422.8 | 1,981.7 | 2,117.7
Other Postretirement Benefits |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Benefit obligation at beginning of year | 556.2 | 590.8 |
Service cost | 6.5 | 6.2 | 6.6
Interest cost | 12.0 | 9.9 | 15.4
Plan participants' contributions | 4.1 | 4.2 |
Plan amendments | 2.1 | 0.1 |
Defined Benefit Plan, Benefit Obligation, Actuarial Gain (Loss) | (89.9) | (14.8) |
Defined Benefit Plan, Benefit Obligation, Benefits Paid | 42.3 | 40.6 |
Estimated benefits paid by incurred subsidy | 0.3 | 0.4 |
Projected benefit obligation at end of year | 449.0 | 556.2 | 590.8
Actual return on plan assets | (51.9) | 23.9 |
Employer contributions | 21.3 | 19.8 |
Defined Benefit Plan, Plan Assets, Contributions by Plan Participant | 4.1 | 4.2 |
Benefits paid | (42.3) | (40.6) |
Defined Benefit Plan, Funded (Unfunded) Status of Plan | (224.1) | (262.5) |
Noncurrent assets | 0.0 | 0.0 |
Current liabilities | (1.0) | (1.0) |
Net amount recognized at end of year | (224.1) | (262.5) |
Unrecognized prior service cost | (3.4) | (7.8) |
Unrecognized actuarial loss | 64.0 | 88.5 |
Defined Benefit Plan Amounts Recognized In Other Comprehensive Income Or Regulatory Asset Or Liability | 60.6 | 80.7 |
Other Postretirement Benefits | Fair Value, Inputs, Level 1, 2 and 3 |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Fair value of plan assets at beginning of year | 293.7 | 286.4 |
Fair value of plan assets at end of year | $ 224.9 | $ 293.7 | $ 286.4

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