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Employee Benefit Plans 11 (Details)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Healthcare Cost Trend Rate
Initial health care cost for employees under age of 65 (as a percent)	5.20%
Ultimate health care cost for employees under age of 65 (as a percent)	4.40%
Initial Health care cost for employees of age 65 and over (as a percent)	4.30%
Ultimate health care cost for employees of age 65 and over (as a percent)	4.00%
Union plan
Employee benefit plans
Expected long-term return on plan assets	6.00%	6.00%	6.00%
Non-union plan
Employee benefit plans
Expected long-term return on plan assets	4.20%	4.20%	4.20%

X

- Definition

Represents the initial health care cost for employees of age sixty-five and over.

+ References

No definition available.

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- Definition

Represents the initial health care cost for employees under age of sixty-five.

+ References

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- Definition

The ultimate trend rate for health care costs for employees of age sixty-five and over.

+ References

No definition available.

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- Definition

The ultimate trend rate for health care costs for employees under age of sixty-five.

+ 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

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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