Income taxes (Details)	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Income Tax Contingency [Line Items]
Effective income tax, percent	20.00%	19.00%
Hawaiian Electric Company, Inc. and Subsidiaries
Income Tax Contingency [Line Items]
Effective income tax, percent	21.00%	20.00%

Percentage of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 740
-SubTopic 10
-Section 50
-Paragraph 12
-URI http://asc.fasb.org/extlink&oid=121826272&loc=d3e32687-109319

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Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration