Maui windstorm and wildfires - Utilities Charged (Details) - Natural Disasters and Other Casualty Events - USD ($) $ in Thousands	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023	Dec. 31, 2023
Maui Windstorm and Wildfires
Public Utilities, General Disclosures [Line Items]
Total Maui windstorm and wildfires related expenses	$ 236,396	$ 102,582	$ 2,014,809	$ 102,582	$ 138,383
Insurance recovery	(52,158)	(75,000)	(83,610)	(75,000)	(104,580)
Deferral treatment approved by the PUC	(8,589)	0	(24,143)	0	(14,692)
Total Maui windstorm and wildfires related expenses, net of insurance recoveries and approved deferral treatment	175,649	27,582	1,907,056	27,582	19,111
Legal expenses
Public Utilities, General Disclosures [Line Items]
Total Maui windstorm and wildfires related expenses	17,963	10,751	57,990	10,751	34,876
Wildfire tort-related claims
Public Utilities, General Disclosures [Line Items]
Total Maui windstorm and wildfires related expenses	203,000	75,000	1,915,000	75,000	75,000
Other expense
Public Utilities, General Disclosures [Line Items]
Total Maui windstorm and wildfires related expenses	15,433	16,831	41,819	16,831	28,507
Hawaiian Electric Company, Inc. and Subsidiaries | Maui Windstorm and Wildfires
Public Utilities, General Disclosures [Line Items]
Total Maui windstorm and wildfires related expenses	228,250	88,942	1,991,692	88,942	114,808
Insurance recovery	(49,625)	(75,000)	(75,973)	(75,000)	(98,613)
Deferral treatment approved by the PUC	(8,589)	0	(24,143)	0	(14,692)
Total Maui windstorm and wildfires related expenses, net of insurance recoveries and approved deferral treatment	170,036	13,942	1,891,576	13,942	1,503
Hawaiian Electric Company, Inc. and Subsidiaries | Legal expenses
Public Utilities, General Disclosures [Line Items]
Total Maui windstorm and wildfires related expenses	11,821	6,251	40,169	6,251	24,737
Hawaiian Electric Company, Inc. and Subsidiaries | Wildfire tort-related claims
Public Utilities, General Disclosures [Line Items]
Total Maui windstorm and wildfires related expenses	203,000	75,000	1,915,000	75,000	75,000
Hawaiian Electric Company, Inc. and Subsidiaries | Other expense
Public Utilities, General Disclosures [Line Items]
Total Maui windstorm and wildfires related expenses	$ 13,429	$ 7,691	$ 36,523	$ 7,691	$ 15,071