Pension Plans And Other Post-Retirement Benefits (Schedule Of Assumptions Related To Pension And Other Postretirement Benefit Plans) (Details)	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	6.50%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.30%	3.66%	4.13%
Expected return on plan assets	6.50%	6.75%	7.00%
Pension Benefits [Member] \| Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.35%	4.30%
Pension Benefits [Member] \| Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	3.00%	3.00%	3.00%
Pension Benefits [Member] \| Minimum [Member] \| Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	3.00%	3.00%
Pension Benefits [Member] \| Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	4.00%	4.00%	4.00%
Pension Benefits [Member] \| Maximum [Member] \| Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Rate of compensation increase	4.00%	4.00%
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	4.34%	3.73%	4.25%
Health care cost trend rate	6.60%	7.00%	6.60%
Rate to which the cost trend is assumed to decline (the ultimate trend rate)	5.00%	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2023	2023	2021
Other Postretirement Benefits [Member] \| Obligations [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate	3.42%	4.34%
Health care cost trend rate	6.25%	6.60%
Rate to which the cost trend is assumed to decline (the ultimate trend rate)	5.00%	5.00%
Year that the rate reaches the ultimate trend rate	2024	2022
Other Postretirement Benefits [Member] \| Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	4.10%	4.25%	4.67%
Other Postretirement Benefits [Member] \| Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected return on plan assets	6.50%	6.75%	7.00%

Weighted average rate for present value of future retirement benefits cash flows, used to determine benefit obligation of defined benefit plan.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(1)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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- Definition

Weighted average rate of return on plan assets, reflecting average rate of earnings expected on existing plan assets and expected contributions, used to determine net periodic benefit cost of defined benefit plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(3)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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Weighted average rate of compensation increase used to determine net periodic benefit cost of defined benefit plan. Plan includes, but is not limited to, pay-related defined benefit plan.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (k)(2)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Ultimate trend rate for health care cost for defined benefit postretirement plan.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
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-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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Year ultimate health care cost trend rate is expected to be reached, in CCYY format.

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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (l)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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- Definition

Defined Benefit Plan Ultimate Trend Rate

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