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Retirement Plans, Weighted Average Assumptions Used to Determine Net Periodic Benefit Cost, Other Postretirement Benefits (Details) - Other Postretirement Benefits [Member] | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019 | Dec. 31, 2018
Weighted average assumptions used to determine net periodic benefit cost [Abstract] |  |  |
Discount rate | 3.50% | 4.40% | 3.70%
Health care cost trend rate [Abstract] |  |  |
Initial rate | 6.75% | 7.00% | 7.00%
Ultimate rate | 5.00% | 5.00% | 5.00%
Years to ultimate | 2025 | 2025 | 2022

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- Definition Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Initial Health Care Cost Trend Rate + References No definition available. + Details
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- Definition Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Ultimate Health Care Cost Trend Rate + References No definition available. + Details
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- Definition Year ultimate health care cost trend rate is expected to be reached, in CCYY format. + References No definition available. + Details
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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 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)(1) -URI http://asc.fasb.org/extlink&oid=118255775&loc=d3e1928-114920 + Details
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- Details
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