Pensions and Other Postretirement Benefits - Assumptions Used (Details)	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefits
Weighted Average Assumptions:
Discount Rate	2.69%	4.14%	3.49%
Rate of Increase in Future Compensation Levels	2.36%	2.37%	2.09%
Expected Long-Term Rate of Return on Plan Assets	4.12%	4.74%	4.86%
Initial Health Care Cost Trend Rate	0.00%	0.00%	0.00%
Ultimate Health Care Cost Trend Rate	0.00%	0.00%	0.00%
Postretirement Health Coverage
Weighted Average Assumptions:
Discount Rate	3.22%	4.29%	3.64%
Rate of Increase in Future Compensation Levels	0.00%	0.00%	0.00%
Expected Long-Term Rate of Return on Plan Assets	0.00%	0.00%	0.00%
Initial Health Care Cost Trend Rate	6.65%	9.00%	9.00%
Ultimate Health Care Cost Trend Rate	4.50%	4.50%	4.50%

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

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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.

+ 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.

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- Definition

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

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- References

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