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v3.22.4

Summary of significant accounting policies - General, Cash, and PPE (Details) $ in Thousands | 12 Months Ended
--- | ---
Dec. 31, 2022 USD ($) branch | Dec. 31, 2021 USD ($) | Dec. 31, 2020
Significant Accounting Policies [Line Items] |  |  |
Number of branches | 38 |  |
Restricted cash | $ | $ 5,100 | $ 5,900 |
Oahu |  |  |
Significant Accounting Policies [Line Items] |  |  |
Number of branches | 27 |  |
Maui |  |  |
Significant Accounting Policies [Line Items] |  |  |
Number of branches | 5 |  |
Hawaii |  |  |
Significant Accounting Policies [Line Items] |  |  |
Number of branches | 3 |  |
Kauai |  |  |
Significant Accounting Policies [Line Items] |  |  |
Number of branches | 2 |  |
Molokai |  |  |
Significant Accounting Policies [Line Items] |  |  |
Number of branches | 1 |  |
Hawaiian Electric Company, Inc. and Subsidiaries |  |  |
Significant Accounting Policies [Line Items] |  |  |
Composite annual depreciation rate | 3.20% | 3.20% | 3.20%
Minimum |  |  |
Significant Accounting Policies [Line Items] |  |  |
Estimated useful life under production plant (in years) | 16 years |  |
Estimated useful life under transmission and distribution plant (in years) | 10 years |  |
Estimated useful life under general plant (in years) | 5 years |  |
Maximum |  |  |
Significant Accounting Policies [Line Items] |  |  |
Estimated useful life under production plant (in years) | 51 years |  |
Estimated useful life under transmission and distribution plant (in years) | 79 years |  |
Estimated useful life under general plant (in years) | 50 years |  |
Hawaiian Electric Company, Inc. and Subsidiaries |  |  |
Significant Accounting Policies [Line Items] |  |  |
Restricted cash | $ | $ 0 | $ 3,089 |

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- Definition Useful life of assets common to business units owned by public utility, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition Amount of cash and cash equivalents restricted as to withdrawal or usage, classified as current. Cash includes, but is not limited to, currency on hand, demand deposits with banks or financial institutions, and other accounts with general characteristics of demand deposits. Cash equivalents include, but are not limited to, short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 4 -URI https://asc.fasb.org/extlink&oid=126954810&loc=d3e3044-108585 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 50 -Paragraph 8 -URI https://asc.fasb.org/extlink&oid=126999549&loc=SL98516268-108586 Reference 3: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02(1)) -URI https://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
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