Electric utility segment - Cumulative Preferred Stock (Details)	Dec. 31, 2019 $ / shares
Series C, D, E, H, J and K Preferred Stock \| Hawaiian Electric
Class of Stock [Line Items]
Voluntary liquidation price	$ 20
Redemption price	21
Series I Preferred Stock \| Hawaiian Electric
Class of Stock [Line Items]
Voluntary liquidation price	20
Redemption price	20
Series G Preferred Stock \| Hawaii Electric Light Company, Inc. (HELCO)
Class of Stock [Line Items]
Voluntary liquidation price	100
Redemption price	100
Series H Preferred Stock \| Maui Electric Company, Limited (MECO)
Class of Stock [Line Items]
Voluntary liquidation price	100
Redemption price	$ 100

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.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 5
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21488-112644

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21475-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21564-112644

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