Benefit Plans (Assumptions used to Determine Net Periodic Benefit Cost) (Details)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate: Service cost	3.70%	4.60%	3.80%
Discount rate: Interest cost	3.00%	4.00%	3.30%
Expected rate of return on plan assets	6.60%	7.80%	7.80%
Rate of compensation increase	4.00%	4.00%	4.00%
Postretirement Benefit Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount rate: Service cost	3.60%	4.50%	3.80%
Discount rate: Interest cost	3.00%	4.00%	3.30%
Expected rate of return on plan assets	7.70%	7.80%	7.80%
Health care cost trend rate	6.50%	6.50%	7.00%

Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate, Interest Cost

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- Definition

Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate, Service Cost

+ References

No definition available.

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- Definition

Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Ultimate Health Care Cost Trend Rate

+ References

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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

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