Shareholders' equity - Schedule of Reclassification Out of AOCI (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
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Assets of discontinued operations	$ 0				$ 9,566,449				$ 0	$ 9,566,449
Income (loss) from discontinued operations	(97,411)	$ 18,778	$ (45,787)	$ 20,934	3,231	$ 11,365	$ 20,204	$ 18,562	(103,486)	53,362	$ 79,989
Interest expense									127,207	125,532	103,402
Hawaiian Electric Company, Inc. and Subsidiaries
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)									1,224,367	(195,947)	(190,924)
Amount reclassified from AOCI
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)									(52,627)	15,402	(176,112)
Amount reclassified from AOCI | Hawaiian Electric Company, Inc. and Subsidiaries
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)									(65,743)	(10,187)	(181,052)
Amount reclassified from AOCI | Net unrealized gains (losses) on securities
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Assets of discontinued operations	$ 0				$ 10,954				0	10,954	0
Amount reclassified from AOCI | Amortization of unrealized holding losses on held-to-maturity securities
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Income (loss) from discontinued operations									13,012	14,398	3,993
Amount reclassified from AOCI | Net realized losses (gains) on derivatives qualifying as cash flow hedges
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Interest expense									(201)	(186)	172
Amount reclassified from AOCI | Amortization of prior service credit and net losses (gains) recognized during the period in net periodic benefit cost
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)									(1,730)	(1,560)	19,659
Amount reclassified from AOCI | Amortization of prior service credit and net losses (gains) recognized during the period in net periodic benefit cost | Hawaiian Electric Company, Inc. and Subsidiaries
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)									(2,035)	(1,983)	18,884
Amount reclassified from AOCI | Impact of D&Os of the PUC included in regulatory assets
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)									(63,708)	(8,204)	(199,936)
Amount reclassified from AOCI | Impact of D&Os of the PUC included in regulatory assets | Hawaiian Electric Company, Inc. and Subsidiaries
Reclassification Adjustment Out of Accumulated Other Comprehensive Income [Line Items]
Net income (loss)									$ (63,708)	$ (8,204)	$ (199,936)