Credit agreements, long-term debt and changes in long-term debt - Schedule of Long-Term Debt (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
	Sep. 30, 2025	Dec. 31, 2024
Debt Instrument [Line Items]
Less current portion long-term debt, net of unamortized debt issuance cost and debt discount	$ (143,472)	$ (109,171)
Long-term debt, net	2,295,219	2,690,387
Hawaiian Electric Company, Inc. and Subsidiaries
Debt Instrument [Line Items]
Less unamortized debt issuance costs and debt discount	(12,467)	(6,786)
Less current portion long-term debt, net of unamortized debt issuance cost and debt discount	(124,928)	(47,000)
Long-term debt, net	2,057,605	1,854,214
All Other
Debt Instrument [Line Items]
Less unamortized debt issuance costs and debt discount	(628)	(6,681)
Less current portion long-term debt, net of unamortized debt issuance cost and debt discount	(18,544)	(62,171)
Long-term debt, net	237,614	836,173
HEI 2.48%-6.10% senior notes due 2025-2052 | Senior Notes | All Other
Debt Instrument [Line Items]
Aggregate principal amount, issued	226,286	610,000
Pacific Current subsidiaries nonrecourse debt | All Other
Debt Instrument [Line Items]
Aggregate principal amount, issued	0	122,025
HEI Revolving Facility SOFR + 2.50%, due 2030 | Line of credit facility | All Other
Debt Instrument [Line Items]
Aggregate principal amount, issued	$ 30,500	173,000
Line of credit facility basis point spread (as percent)	2.50%
Special purpose revenue bonds and unsecured senior notes | Hawaiian Electric Company, Inc. and Subsidiaries
Debt Instrument [Line Items]
Aggregate principal amount, issued	$ 2,195,000	1,742,000
Hawaiian Electric Revolving Facility SOFR + 2.25%, due 2026 | Line of credit facility | Hawaiian Electric Company, Inc. and Subsidiaries
Debt Instrument [Line Items]
Aggregate principal amount, issued	$ 0	$ 166,000
Line of credit facility basis point spread (as percent)	2.25%
Revolving Credit Facility At 1.80% Due 2026 To 2027 | Line of credit facility | Hawaiian Electric Company, Inc. and Subsidiaries
Debt Instrument [Line Items]
Line of credit facility basis point spread (as percent)		1.80%
Maximum | HEI 2.48%-6.10% senior notes due 2025-2052 | Senior Notes
Debt Instrument [Line Items]
Stated interest rate (as percent)	6.10%
Minimum | HEI 2.48%-6.10% senior notes due 2025-2052 | Senior Notes
Debt Instrument [Line Items]
Stated interest rate (as percent)	2.48%