Electric utility segment - Condensed Consolidating Statement of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2024	Mar. 31, 2024	Jun. 30, 2023	Mar. 31, 2023	Jun. 30, 2024	Jun. 30, 2023
Condensed Statement of Income Captions [Line Items]
Net loss for common stock	$ (1,295,484)	$ 42,122	$ 54,610	$ 54,721	$ (1,253,362)	$ 109,331
Retirement benefit plans:
Adjustment for amortization of prior service credit and net gains recognized during the period in net periodic benefit cost, net of taxes of $(155), $(122), $(309) and $(244), respectively	(445)		(357)		(894)	(714)
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes	459		426		918	851
Other comprehensive loss, net of taxes	1,594	(9,801)	(7,609)	20,488	(8,207)	12,879
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	(1,293,890)		47,001		(1,261,569)	122,210
Hawaiian Electric Consolidated
Condensed Statement of Income Captions [Line Items]
Net loss for common stock	(1,229,394)	39,221	45,299	47,009	(1,190,173)	92,308
Retirement benefit plans:
Adjustment for amortization of prior service credit and net gains recognized during the period in net periodic benefit cost, net of taxes of $(155), $(122), $(309) and $(244), respectively	(505)		(470)		(1,013)	(940)
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes	459		426		918	851
Other comprehensive loss, net of taxes	(46)	$ (49)	(44)	$ (45)	(95)	(89)
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	(1,229,440)		45,255		(1,190,268)	92,219
Consolidating adjustments | Hawaiian Electric Consolidated
Condensed Statement of Income Captions [Line Items]
Net loss for common stock	246,099		(11,414)		240,075	(22,955)
Retirement benefit plans:
Adjustment for amortization of prior service credit and net gains recognized during the period in net periodic benefit cost, net of taxes of $(155), $(122), $(309) and $(244), respectively	96		121		193	240
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes	(85)		(110)		(169)	(217)
Other comprehensive loss, net of taxes	11		11		24	23
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	246,110		(11,403)		240,099	(22,932)
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Condensed Statement of Income Captions [Line Items]
Net loss for common stock	(1,229,394)		45,299		(1,190,173)	92,308
Retirement benefit plans:
Adjustment for amortization of prior service credit and net gains recognized during the period in net periodic benefit cost, net of taxes of $(155), $(122), $(309) and $(244), respectively	(505)		(470)		(1,013)	(940)
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes	459		426		918	851
Other comprehensive loss, net of taxes	(46)		(44)		(95)	(89)
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	(1,229,440)		45,255		(1,190,268)	92,219
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Consolidated
Condensed Statement of Income Captions [Line Items]
Net loss for common stock	(120,295)		7,075		(115,905)	13,465
Retirement benefit plans:
Adjustment for amortization of prior service credit and net gains recognized during the period in net periodic benefit cost, net of taxes of $(155), $(122), $(309) and $(244), respectively	(39)		(55)		(77)	(111)
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes	35		53		70	103
Other comprehensive loss, net of taxes	(4)		(2)		(7)	(8)
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	(120,299)		7,073		(115,912)	13,457
Maui Electric | Reportable Legal Entities | Hawaiian Electric Consolidated
Condensed Statement of Income Captions [Line Items]
Net loss for common stock	(125,804)		4,339		(124,170)	9,490
Retirement benefit plans:
Adjustment for amortization of prior service credit and net gains recognized during the period in net periodic benefit cost, net of taxes of $(155), $(122), $(309) and $(244), respectively	(57)		(66)		(116)	(129)
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes	50		57		99	114
Other comprehensive loss, net of taxes	(7)		(9)		(17)	(15)
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	(125,811)		4,330		(124,187)	9,475
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Consolidated
Condensed Statement of Income Captions [Line Items]
Net loss for common stock	0		0		0	0
Retirement benefit plans:
Adjustment for amortization of prior service credit and net gains recognized during the period in net periodic benefit cost, net of taxes of $(155), $(122), $(309) and $(244), respectively	0		0		0	0
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes	0		0		0	0
Other comprehensive loss, net of taxes	0		0		0	0
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	$ 0		$ 0		$ 0	$ 0