SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF REGISTRANT - Narrative (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Condensed Financial Statements, Captions [Line Items]
Less unamortized debt issuance costs and debt discount	$ (8,097)	$ (8,165)
Long-term debt, net—other than bank	2,842,429	2,384,980
Aggregate principal payments, fiscal year maturity:
2024	18,000
2025	109,000
2026	174,000
2027	449,000
2028	273,000
Line of credit facility | HEI revolving credit facility SOFR + 1.80%, due 2026 to 2027
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 175,000	0
Weighted average interest rate (as percent)	7.19%
Line of credit facility | HEI revolving credit facility SOFR + 1.80%, due 2026 to 2027 | SOFR
Condensed Financial Statements, Captions [Line Items]
Line of credit facility basis point spread	1.80%
Line of credit facility | HEI revolving credit facility SOFR + 1.80%, due 2026 to 2027 | Secured Overnight Financing Rate (SOFR) Excluding Sustainability Margin And Additional Adjustments
Condensed Financial Statements, Captions [Line Items]
Line of credit facility basis point spread	1.75%
Line of credit facility | HEI revolving credit facility SOFR + 1.80%, due 2026 to 2027 | Secured Overnight Financing Rate (SOFR), Sustainability Margin Adjustment
Condensed Financial Statements, Captions [Line Items]
Line of credit facility basis point spread	0.05%
Line of credit facility | HEI revolving credit facility SOFR + 1.80%, due 2026 to 2027 | Secured Overnight Financing Rate (SOFR), Additional Adjustment
Condensed Financial Statements, Captions [Line Items]
Line of credit facility basis point spread	0.10%
Hawaiian Electric
Condensed Financial Statements, Captions [Line Items]
Less unamortized debt issuance costs and debt discount	$ (2,995)	(2,126)
Long-term debt, net—other than bank	782,005	557,874
Aggregate principal payments, fiscal year maturity:
2024	0
2025	50,000
2026	18,000
2027	157,000
2028	193,000
Thereafter	367,000
Cash dividends paid	168,000	168,000	$ 172,000
HEI DRIP transaction	5,400	0	0
Hawaiian Electric | ASB Hawaii, Inc. | Consolidated subsidiary
Aggregate principal payments, fiscal year maturity:
Accounts receivable reduction	2,300	1,900	2,100
HEI notes payable increase to ASHI	2,300	1,900	$ 2,100
Hawaiian Electric | HEI 3.99% senior notes, paid in 2023
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 0	50,000
Debt instrument, stated interest rate (as percent)	3.99%
Hawaiian Electric | HEI 4.58% senior notes, due 2025
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 50,000	50,000
Debt instrument, stated interest rate (as percent)	4.58%
Hawaiian Electric | HEI 4.72% senior notes, due 2028
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 100,000	100,000
Debt instrument, stated interest rate (as percent)	4.72%
Hawaiian Electric | HEI 2.82% senior notes, due 2028
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 24,000	24,000
Debt instrument, stated interest rate (as percent)	2.82%
Hawaiian Electric | HEI 2.48% senior notes, due 2028
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 30,000	30,000
Debt instrument, stated interest rate (as percent)	2.48%
Hawaiian Electric | HEI 6.04% senior notes, due 2028
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 39,000	0
Debt instrument, stated interest rate (as percent)	6.04%
Hawaiian Electric | HEI 2.98% senior notes, due 2030
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 50,000	50,000
Debt instrument, stated interest rate (as percent)	2.98%
Hawaiian Electric | HEI 3.15% senior notes, due 2031
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 51,000	51,000
Debt instrument, stated interest rate (as percent)	3.15%
Hawaiian Electric | HEI 2.78% senior notes, due 2031
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 25,000	25,000
Debt instrument, stated interest rate (as percent)	2.78%
Hawaiian Electric | HEI 2.98% senior notes, due 2032
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 30,000	30,000
Debt instrument, stated interest rate (as percent)	2.98%
Hawaiian Electric | HEI 5.43% senior notes, due 2032
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 75,000	75,000
Debt instrument, stated interest rate (as percent)	5.43%
Hawaiian Electric | HEI 6.10% senior notes, due 2033
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 61,000	0
Hawaiian Electric | HEI 5.43% senior notes, due 2034
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 35,000	35,000
Debt instrument, stated interest rate (as percent)	5.43%
Hawaiian Electric | HEI 3.74% senior notes, due 2051
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 20,000	20,000
Debt instrument, stated interest rate (as percent)	3.74%
Hawaiian Electric | HEI 3.94% senior notes, due 2052
Condensed Financial Statements, Captions [Line Items]
Gross long-term debt	$ 20,000	$ 20,000
Debt instrument, stated interest rate (as percent)	3.94%