Electric utility segment - Condensed consolidating statement of comprehensive income (Details) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended
	Jun. 30, 2022	Mar. 31, 2022	Jun. 30, 2021	Mar. 31, 2021	Jun. 30, 2022	Jun. 30, 2021
Condensed Statement of Income Captions [Line Items]
Net income for common stock	$ 52,541	$ 69,167	$ 63,872	$ 64,358	$ 121,708	$ 128,230
Retirement benefit plans:
Adjustment for amortization of prior service credit and net losses recognized during the period in net periodic benefit cost, net of taxes	122		6,008		4,623	12,018
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes	56		(5,811)		(4,269)	(11,622)
Other comprehensive income (loss), net of taxes	(87,840)	(117,159)	16,472	(44,016)	(204,999)	(27,544)
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	(35,299)		80,344		(83,291)	100,686
Hawaiian Electric Consolidated
Condensed Statement of Income Captions [Line Items]
Net income for common stock	44,135	46,409	41,901	43,358	90,544	85,259
Retirement benefit plans:
Adjustment for amortization of prior service credit and net losses recognized during the period in net periodic benefit cost, net of taxes	(5)		5,846		4,371	11,691
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes	56		(5,811)		(4,269)	(11,622)
Other comprehensive income (loss), net of taxes	51	$ 51	35	$ 34	102	69
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	44,186		41,936		90,646	85,328
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaiian Electric
Condensed Statement of Income Captions [Line Items]
Net income for common stock	44,135		41,901		90,544	85,259
Retirement benefit plans:
Adjustment for amortization of prior service credit and net losses recognized during the period in net periodic benefit cost, net of taxes	(5)		5,846		4,371	11,691
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes	56		(5,811)		(4,269)	(11,622)
Other comprehensive income (loss), net of taxes	51		35		102	69
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	44,186		41,936		90,646	85,328
Hawaiian Electric Consolidated | Reportable Legal Entities | Hawaii Electric Light
Condensed Statement of Income Captions [Line Items]
Net income for common stock	5,658		5,607		13,035	12,299
Retirement benefit plans:
Adjustment for amortization of prior service credit and net losses recognized during the period in net periodic benefit cost, net of taxes	(72)		834		598	1,669
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes	74		(834)		(596)	(1,668)
Other comprehensive income (loss), net of taxes	2		0		2	1
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	5,660		5,607		13,037	12,300
Hawaiian Electric Consolidated | Reportable Legal Entities | Maui Electric
Condensed Statement of Income Captions [Line Items]
Net income for common stock	6,579		5,137		12,863	10,955
Retirement benefit plans:
Adjustment for amortization of prior service credit and net losses recognized during the period in net periodic benefit cost, net of taxes	603		761		1,206	1,522
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes	(602)		(761)		(1,205)	(1,522)
Other comprehensive income (loss), net of taxes	1		0		1	0
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	6,580		5,137		12,864	10,955
Hawaiian Electric Consolidated | Reportable Legal Entities | Other subsidiaries
Condensed Statement of Income Captions [Line Items]
Net income for common stock	0		0		0	0
Retirement benefit plans:
Adjustment for amortization of prior service credit and net losses recognized during the period in net periodic benefit cost, net of taxes	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 income (loss), net of taxes	0		0		0	0
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	0		0		0	0
Hawaiian Electric Consolidated | Consolidating adjustments
Condensed Statement of Income Captions [Line Items]
Net income for common stock	(12,237)		(10,744)		(25,898)	(23,254)
Retirement benefit plans:
Adjustment for amortization of prior service credit and net losses recognized during the period in net periodic benefit cost, net of taxes	(531)		(1,595)		(1,804)	(3,191)
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes	528		1,595		1,801	3,190
Other comprehensive income (loss), net of taxes	(3)		0		(3)	(1)
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	$ (12,240)		$ (10,744)		$ (25,901)	$ (23,255)