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Pension and Other Postretirement Benefits (Schedule Of Changes In Plan Assets And Projected Benefit Obligations Recognized In Other Comprehensive Income) (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Pension Plan |  |  |
Net prior service cost/(credit) | $ 0.0 | $ 0.0 |
Net actuarial (gain)/loss | (78.2) | (53.8) |
Settlements | (10.5) | (9.5) | $ (18.5)
Defined Benefit Plan, Amortization of Prior Service Cost (Credit) | (0.7) | (0.2) | 0.4
Less: amortization of net actuarial (gain) loss | (33.8) | (45.2) | (40.6)
Gain Attributable to spinoff to Eversource | (33.1) | 0.0 |
Prior Service Cost attributable to spinoff to Eversource | (2.0) | 0.0 |
Total Recognized in Other Comprehensive Income or Regulatory Asset or Liability | (158.3) | (108.7) |
Amount Recognized in Net Periodic Benefits Cost and Other Comprehensive Income or Regulatory Asset or Liability | (141.3) | (61.1) |
Other Postretirement Benefits |  |  |
Net prior service cost/(credit) | 0.0 | 5.1 |
Net actuarial (gain)/loss | 2.9 | 45.1 |
Settlements | (1.5) | 0.0 | 0.0
Defined Benefit Plan, Amortization of Prior Service Cost (Credit) | 2.1 | 3.2 | 4.0
Less: amortization of net actuarial (gain) loss | (4.9) | (2.0) | $ (3.8)
Gain Attributable to spinoff to Eversource | 0.0 | 0.0 |
Prior Service Cost attributable to spinoff to Eversource | 0.0 | 0.0 |
Total Recognized in Other Comprehensive Income or Regulatory Asset or Liability | (1.4) | 51.4 |
Amount Recognized in Net Periodic Benefits Cost and Other Comprehensive Income or Regulatory Asset or Liability | $ 10.5 | $ 61.4 |

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