Benefit Plans (Schedule Of Assumptions Used) (Details)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Assumptions used to determine benefit obligations: Discount rate	2.33%	3.13%
Assumptions used to determine benefit obligations: Rate of compensation increase	4.00%	4.00%
Assumptions used to determine net periodic benefit cost: Discount rate	3.13%	4.15%
Assumptions used to determine net periodic benefit cost: Expected long-term return on plan assets	6.50%	6.50%
Assumptions used to determine net periodic benefit cost: Rate of compensation increase	4.00%	4.00%
Asset allocations as of measurement date:	100.00%	100.00%
Cash and Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations as of measurement date:	12.00%	4.00%
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations as of measurement date:	22.00%	21.00%
Corporate Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations as of measurement date:	13.00%	13.00%
Municipal Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations as of measurement date:	26.00%	35.00%
Investment Fund-Debt [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations as of measurement date:	9.00%	9.00%
Investment Fund-Equity [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations as of measurement date:	12.00%	10.00%
Deposit In Immediate Participation Guarantee Contract [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations as of measurement date:	6.00%	6.00%
Other Defined Benefit Plan Assets [Member]
Defined Benefit Plan Disclosure [Line Items]
Asset allocations as of measurement date:	0.00%	2.00%

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

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- Definition

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

+ References

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- Definition

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

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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://www.xbrl.org/2003/role/disclosureRef
-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

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e2919-114920

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- Definition

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

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- Definition

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.

+ References

No definition available.

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- Definition

Percentage of actual investment allocation to total plan assets. Includes, but is not limited to, percentage on weighted-average basis if more than one plan.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 715
-SubTopic 20
-Section 50
-Paragraph 1
-Subparagraph (d)(i)
-URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920

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