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Pension and Other Post Retirement Benefit Plans - Schedule of Plan Assets by Category (Details) | Dec. 31, 2020 | Dec. 31, 2019
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Defined Benefit Plan Disclosure [Line Items] |  |
Actual (as a percent) | 100.00% | 100.00%
Target (as a percent) | 100.00% | 100.00%
Cash and cash equivalents |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actual (as a percent) | 2.70% | 3.00%
Target (as a percent) | 3.00% | 3.00%
Equity securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actual (as a percent) | 53.00% | 52.30%
Target (as a percent) | 50.00% | 50.00%
Debt securities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actual (as a percent) | 42.30% | 42.30%
Target (as a percent) | 45.00% | 45.00%
Alternative investments |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actual (as a percent) | 2.00% | 2.40%
Target (as a percent) | 2.00% | 2.00%

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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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