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Employee Benefit Plans: Defined Benefit Pension Plan (Details) - gas_distribution_territory	Dec. 31, 2021	Dec. 31, 2020
Number of Defined Pension Plans	1
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	100.00%	100.00%
Investment in privately held oil and gas company
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	15.00%	21.00%
Real Estate
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	7.00%	3.00%
Fixed Income
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	74.00%	69.00%
Cash
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	1.00%	3.00%
Hedge Funds
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	3.00%	4.00%
Minimum | Return Seeking Assets | Pension Plan
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	22.00%
Minimum | Hedge Funds | Pension Plan
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	70.00%
Maximum | Return Seeking Assets | Pension Plan
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	30.00%
Maximum | Hedge Funds | Pension Plan
Defined Benefit Plan, Plan Assets, Target Allocation, Percentage	78.00%

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+ References

No definition available.

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+ 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

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