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Retirement Plans - Target and Weighted Average Actual Allocations and Benefit Pension Plans (Details) | 12 Months Ended |
--- | --- | ---
Dec. 31, 2020 | Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items] |  |
Actual Allocation (as a percent) | 100.00% | 100.00%
Debt securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actual Allocation (as a percent) | 63.00% | 60.00%
Equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actual Allocation (as a percent) | 28.00% | 31.00%
Other |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actual Allocation (as a percent) | 9.00% | 9.00%
Defined Benefit Pension Plans | Minimum | Debt securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Target Allocation (as a percent) | 55.00% |
Defined Benefit Pension Plans | Minimum | Equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Target Allocation (as a percent) | 25.00% |
Defined Benefit Pension Plans | Minimum | Other |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Target Allocation (as a percent) | 0.00% |
Defined Benefit Pension Plans | Maximum | Debt securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Target Allocation (as a percent) | 65.00% |
Defined Benefit Pension Plans | Maximum | Equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Target Allocation (as a percent) | 35.00% |
Defined Benefit Pension Plans | Maximum | Other |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Target Allocation (as a percent) | 10.00% |
Defined Benefit Pension Plans | Maximum | Common or collective trusts |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Redemption notice period to redeem investments | 30 days |

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- Definition Percentage of target 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/2003/role/exampleRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 55 -Paragraph 17 -URI http://asc.fasb.org/extlink&oid=118257860&loc=d3e4179-114921 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -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 + Details
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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 + Details
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