Shareholders' equity - Reclassification out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Reclassifications out of accumulated other comprehensive income/(loss)
Revenues	$ (895,685)	$ (895,607)	$ (1,823,922)	$ (1,680,675)
Interest expense	29,832	24,965	58,630	49,314
Reclassification out of Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income/(loss)
Total reclassifications	3,710	231	7,407	462
Hawaiian Electric Company, Inc. and Subsidiaries
Reclassifications out of accumulated other comprehensive income/(loss)
Revenues	(794,191)	(818,873)	(1,624,552)	(1,527,665)
Total reclassifications	(45,798)	(44,634)	(93,306)	(91,542)
Hawaiian Electric Company, Inc. and Subsidiaries | Reclassification out of Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income/(loss)
Total reclassifications	(44)	51	(89)	102
Net unrealized gains (losses) on available-for sale investment securities - amortization of unrealized holding losses on held-to-maturity securities | Reclassification out of Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income/(loss)
Revenues	3,689	0	7,366	0
Net realized losses (gains) on derivatives qualifying as cash flow hedges | Reclassification out of Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income/(loss)
Interest expense	(48)	53	(96)	108
Amortization of prior service credit and net losses (gains) recognized during the period in net periodic benefit cost | Reclassification out of Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income/(loss)
Total reclassifications	(357)	122	(714)	4,623
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 out of Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income/(loss)
Total reclassifications	(470)	(5)	(940)	4,371
Impact of D&Os of the PUC included in regulatory assets | Reclassification out of Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income/(loss)
Total reclassifications	426	56	851	(4,269)
Impact of D&Os of the PUC included in regulatory assets | Hawaiian Electric Company, Inc. and Subsidiaries | Reclassification out of Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income/(loss)
Total reclassifications	$ 426	$ 56	$ 851	$ (4,269)