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Pension Plans And Other Postretirement Benefit Plans (Components Of Net Periodic Benefit Cost) (Details) - USD ($) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2019 | Dec. 31, 2018 | Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage of Net Periodic Benefit Costs Capitalized to Utility Property | 40.00% |  |
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax | $ (10,259) | $ (7,866) |
Percentage of Net Periodic Benefit Costs Recorded to Operating Expenses | 60.00% |  |
Pension Plan And SERP [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax | $ 9,078 | 7,587 |
Service cost | 19,755 | 21,614 | $ 20,406
Interest cost | 28,417 | 26,096 | 27,898
Expected return on plan assets | (31,763) | (33,018) | (31,626)
Amortization of prior service cost | 257 | 257 | 2
Net loss recognition | 10,216 | 7,879 | 9,793
Net periodic benefit cost | 26,882 | 22,828 | 26,473
Other Postretirement Benefits [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined Benefit Plan, Accumulated Other Comprehensive Income (Loss), after Tax | 1,181 | 279 |
Service cost | 3,006 | 3,188 | 3,220
Interest cost | 5,598 | 4,831 | 5,490
Expected return on plan assets | (2,101) | (1,973) | (1,899)
Amortization of prior service cost | (981) | (1,089) | (1,144)
Net loss recognition | 4,013 | 4,232 | 4,934
Net periodic benefit cost | $ 9,535 | $ 9,189 | $ 10,601

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- Definition Amount, after tax, of accumulated other comprehensive (income) loss for defined benefit plan, that has not been recognized in net periodic benefit cost (credit). + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 14A -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669686-108580 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 220 -SubTopic 10 -Section 45 -Paragraph 10A -Subparagraph (i-k) -URI http://asc.fasb.org/extlink&oid=118930883&loc=SL7669646-108580 + Details
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