Shareholders' equity - Reclassification out of AOCI (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Reclassifications out of accumulated other comprehensive income/(loss)
Revenues	$ (928,237)	$ (785,068)
Interest expense	28,798	24,349
Reclassification out of Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income/(loss)
Total reclassifications	3,697	231
Hawaiian Electric Company, Inc. and Subsidiaries
Reclassifications out of accumulated other comprehensive income/(loss)
Revenues	(830,361)	(708,792)
Total reclassifications	(47,508)	(46,908)
Hawaiian Electric Company, Inc. and Subsidiaries | Reclassification out of Accumulated Other Comprehensive Income
Reclassifications out of accumulated other comprehensive income/(loss)
Total reclassifications	(45)	51
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	3,677	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)	55
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)	4,501
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)	4,376
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	425	(4,325)
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	$ 425	$ (4,325)