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Employee Benefit Plans: Defined Benefit Pension Plan (Details) - PensionPlan | Dec. 31, 2023 | Dec. 31, 2022
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Number of Defined Pension Plans | 1 |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 100.00% | 100.00%
Return Seeking Assets |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 24.00% | 26.00%
Liability-hedging Assets |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 76.00% | 74.00%
Investment in privately held oil and gas company | Return Seeking Assets |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 14.00% | 14.00%
Real Estate | Return Seeking Assets |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 5.00% | 7.00%
Fixed Income | Return Seeking Assets |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 2.00% | 2.00%
Fixed Income | Liability-hedging Assets |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 74.00% | 72.00%
Hedge Funds | Return Seeking Assets |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 3.00% | 3.00%
Cash | Liability-hedging Assets |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 2.00% | 2.00%
Minimum | Return Seeking Assets | Pension Plan |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 20.00% |
Minimum | Hedge Funds | Pension Plan |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 72.00% |
Maximum | Return Seeking Assets | Pension Plan |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 28.00% |
Maximum | Hedge Funds | Pension Plan |  |
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage | 80.00% |

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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 -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 17 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480482/715-20-55-17 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 1 -Subparagraph (d)(i) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-1 + Details
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