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PENSION AND POST-RETIREMENT PLANS - ASSET ALLOCATION (Details) - plan | 12 Months Ended |
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Dec. 31, 2020 | Dec. 31, 2019
Employee benefit plans |  |
Number of single-employer defined benefit pension funded plans | 2 |
Pension Benefits |  |
Employee benefit plans |  |
Target allocation (as a percent) | 100.00% |
Asset allocations (as a percent) | 100.00% | 100.00%
One year returns (losses) on plan assets (as a percent) | 12.00% |
Three year returns (losses) on plan assets (as a percent) | 8.70% |
Five year returns (losses) on plan assets (as a percent) | 9.80% |
Long-term average return on plan assets since inception (as a percent) | 8.50% |
Pension Benefits | Domestic equity securities |  |
Employee benefit plans |  |
Target allocation (as a percent) | 53.00% |
Asset allocations (as a percent) | 60.00% | 59.00%
Pension Benefits | International equity securities |  |
Employee benefit plans |  |
Target allocation (as a percent) | 15.00% |
Asset allocations (as a percent) | 17.00% | 17.00%
Pension Benefits | Debt securities |  |
Employee benefit plans |  |
Target allocation (as a percent) | 22.00% |
Asset allocations (as a percent) | 17.00% | 17.00%
Pension Benefits | Real estate |  |
Employee benefit plans |  |
Target allocation (as a percent) | 5.00% |
Asset allocations (as a percent) | 5.00% | 6.00%
Pension Benefits | Other and cash |  |
Employee benefit plans |  |
Target allocation (as a percent) | 5.00% |
Asset allocations (as a percent) | 1.00% | 1.00%

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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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