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Employee Postretirement Benefits - Asset Allocation Ranges By Asset Class and PBO Funded Status (Details) - Pension Plan | Dec. 31, 2021 | Dec. 31, 2020
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Defined Benefit Plan Disclosure [Line Items] |  |
Actual Allocation | 100.00% | 100.00%
Return Enhancement |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actual Allocation | 47.00% | 58.00%
Return Enhancement | 20 - 60% | Minimum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Permitted Range | 20.00% |
Return Enhancement | 20 - 60% | Maximum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Permitted Range | 60.00% |
Risk Management |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actual Allocation | 50.00% | 39.00%
Risk Management | 40 - 80% | Minimum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Permitted Range | 40.00% |
Risk Management | 40 - 80% | Maximum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Permitted Range | 80.00% |
Alternatives |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Actual Allocation | 3.00% | 3.00%
Alternatives | 0 - 20% | Minimum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Permitted Range | 0.00% |
Alternatives | 0 - 20% | Maximum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Permitted Range | 20.00% |

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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=123450688&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=123447040&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=123447040&loc=d3e1928-114920 + Details
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