Electric utility segment - Consolidating Statement of Comprehensive Income (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2024	Sep. 30, 2024	Jun. 30, 2024	Mar. 31, 2024	Dec. 31, 2023	Sep. 30, 2023	Jun. 30, 2023	Mar. 31, 2023	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Condensed Statement of Income Captions [Line Items]
Net income (loss) for common stock	$ (68,245)	$ (104,402)	$ (1,295,484)	$ 42,122	$ 48,789	$ 41,118	$ 54,610	$ 54,721	$ (1,426,009)	$ 199,238	$ 241,138
Retirement benefit plans:
Net gains (losses) arising during the period, net of (taxes) benefits									66,355	10,854	188,020
Adjustment for amortization of net gains recognized during the period in net periodic benefit cost, net of taxes									(1,730)	(1,560)	19,659
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of (taxes) benefits									(63,708)	(8,204)	(199,936)
Other comprehensive income (loss), net of taxes									3,184	46,678	(283,495)
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.									(1,422,825)	245,916	(42,357)
Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Statement of Income Captions [Line Items]
Net income (loss) for common stock									(1,226,362)	193,952	188,929
Retirement benefit plans:
Net gains (losses) arising during the period, net of (taxes) benefits									65,680	10,175	187,193
Adjustment for amortization of net gains recognized during the period in net periodic benefit cost, net of taxes									(2,035)	(1,983)	18,884
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of (taxes) benefits									(63,708)	(8,204)	(199,936)
Other comprehensive income (loss), net of taxes									(63)	(12)	6,141
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.									(1,226,425)	193,940	195,070
Consolidating adjustments | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Statement of Income Captions [Line Items]
Net income (loss) for common stock									248,004	(44,809)	(47,493)
Retirement benefit plans:
Net gains (losses) arising during the period, net of (taxes) benefits									(15,450)	(2,236)	(88,797)
Adjustment for amortization of net gains recognized during the period in net periodic benefit cost, net of taxes									402	487	(5,395)
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of (taxes) benefits									14,971	1,730	93,535
Other comprehensive income (loss), net of taxes									(77)	(19)	(657)
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.									247,927	(44,828)	(48,150)
Hawaiian Electric
Condensed Statement of Income Captions [Line Items]
Net income (loss) for common stock									(1,426,009)	199,238	241,138
Hawaiian Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Statement of Income Captions [Line Items]
Net income (loss) for common stock									(1,226,362)	193,952	188,929
Retirement benefit plans:
Net gains (losses) arising during the period, net of (taxes) benefits									65,680	10,175	187,193
Adjustment for amortization of net gains recognized during the period in net periodic benefit cost, net of taxes									(2,035)	(1,983)	18,884
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of (taxes) benefits									(63,708)	(8,204)	(199,936)
Other comprehensive income (loss), net of taxes									(63)	(12)	6,141
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.									(1,226,425)	193,940	195,070
Hawaii Electric Light | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Statement of Income Captions [Line Items]
Net income (loss) for common stock									(116,414)	28,507	21,816
Retirement benefit plans:
Net gains (losses) arising during the period, net of (taxes) benefits									8,108	961	44,411
Adjustment for amortization of net gains recognized during the period in net periodic benefit cost, net of taxes									(159)	(221)	2,811
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of (taxes) benefits									(7,895)	(752)	(46,841)
Other comprehensive income (loss), net of taxes									54	(12)	381
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.									(116,360)	28,495	22,197
Maui Electric | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Statement of Income Captions [Line Items]
Net income (loss) for common stock									(134,872)	16,302	25,677
Retirement benefit plans:
Net gains (losses) arising during the period, net of (taxes) benefits									7,342	1,275	44,386
Adjustment for amortization of net gains recognized during the period in net periodic benefit cost, net of taxes									(243)	(266)	2,584
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of (taxes) benefits									(7,076)	(978)	(46,694)
Other comprehensive income (loss), net of taxes									23	31	276
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.									(134,849)	$ 16,333	$ 25,953
Other subsidiaries | Reportable Legal Entities | Hawaiian Electric Company, Inc. and Subsidiaries
Condensed Statement of Income Captions [Line Items]
Net income (loss) for common stock									3,282
Retirement benefit plans:
Net gains (losses) arising during the period, net of (taxes) benefits									0
Adjustment for amortization of net gains recognized during the period in net periodic benefit cost, net of taxes									0
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of (taxes) benefits									0
Other comprehensive income (loss), net of taxes									0
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.									$ 3,282