Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Statement of Comprehensive Income [Abstract]
Net income (loss) for common stock	$ 123,120	$ (1,426,009)	$ 199,238
Net unrealized gains (losses) on available-for sale investment securities:
Net unrealized gains (losses) on available-for sale investment securities arising during the period, net of taxes of nil, $(4,110) and $7,536 for 2025, 2024 and 2023, respectively	0	(11,227)	20,589
Reclassification adjustment for net realized losses included in net income, net of taxes of nil, nil and $4,011 for 2025, 2024 and 2023, respectively	0	0	10,954
Amortization of unrealized holding losses on held-to-maturity securities, net of taxes of nil, $4,764 and $5,271 for 2025, 2024 and 2023, respectively	0	13,012	14,398
Derivatives qualified as cash flow hedges:
Unrealized interest rate hedging gains (losses), net of taxes of $(169), $237 and $(58) for 2025, 2024 and 2023, respectively	(489)	683	(167)
Reclassification adjustment to net income, net of taxes of $(358), $(70) and $(65) for 2025, 2024 and 2023, respectively	(1,031)	(201)	(186)
Retirement benefit plans:
Net gains arising during the period, net of taxes of $27,010, $23,015 and $3,778 for 2025, 2024 and 2023, respectively	77,873	66,355	10,854
Adjustment for amortization of prior service credit and net gains recognized during the period in net periodic benefit cost, net of taxes of $(713), $(597) and $(535) for 2025, 2024 and 2023, respectively	(2,057)	(1,730)	(1,560)
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of taxes of $(25,811), $(22,096) and $(2,846) for 2025, 2024 and 2023, respectively	(74,419)	(63,708)	(8,204)
Other comprehensive income (loss), net of taxes	(123)	3,184	46,678
Comprehensive income (loss) attributable to Hawaiian Electric Industries, Inc.	$ 122,997	$ (1,422,825)	$ 245,916