Subsequent event (Details) - Subsequent Event $ / shares in Units, $ in Millions	Oct. 15, 2025 USD ($) $ / shares
Hawaiian Electric Company, Inc. and Subsidiaries
Subsequent Event [Line Items]
Amount of cumulative preferred stock redeemed \| $	$ 35.3
Redemption of cumulative preferred stock \| $	$ 1.8
Series C, D, E, H, J, K Preferred Stock \| Hawaiian Electric, Parent
Subsequent Event [Line Items]
Voluntary liquidation price (in dollars per share)	$ 20
Redemption price (in dollars per share)	21
Series I Preferred Stock \| Hawaiian Electric, Parent
Subsequent Event [Line Items]
Voluntary liquidation price (in dollars per share)	20
Redemption price (in dollars per share)	20
Series G Preferred Stock \| Hawaii Electric Light Company, Inc
Subsequent Event [Line Items]
Voluntary liquidation price (in dollars per share)	100
Redemption price (in dollars per share)	100
Series H Preferred Stock \| Maui Electric
Subsequent Event [Line Items]
Voluntary liquidation price (in dollars per share)	100
Redemption price (in dollars per share)	$ 100

Preferred Stock, Voluntary Liquidation Preference Per Share

No definition available.

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- Definition

The excess of (1) fair value of the consideration transferred to the holders of the preferred stock over (2) the carrying amount of the preferred stock in the registrant's balance sheet, during the accounting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 260
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147480408/260-10-S99-2

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- Definition

The price per share at which the preferred stock of an entity that has priority over common stock in the distribution of dividends and in the event of liquidation of the entity is redeemed or may be called at. The redemption features of this preferred stock are solely within the control of the issuer.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-Publisher FASB
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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-Subparagraph (a)
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- Definition

Cash inflows (outflows) from issuing and redeeming redeemable preferred stock; includes convertible and nonconvertible redeemable preferred stock.

+ References

No definition available.

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- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 830
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147481674/830-30-50-2

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 855
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147483399/855-10-50-2

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