Retirement benefits (Tables)

6 Months Ended

Jun. 30, 2025

Retirement Benefits [Abstract]

Schedule of Components of Net Periodic Benefit Cost for Consolidated HEI

The components of net periodic pension costs and net periodic benefit costs for HEI consolidated and Hawaiian Electric consolidated were as follows:

	Three months ended June 30								Six months ended June 30
	Pension benefits				Other benefits				Pension benefits				Other benefits
(in thousands)	2025		2024		2025		2024		2025		2024		2025		2024
HEI consolidated
Service cost	$	9,948	$	11,178	$	248	$	282	$	19,896	$	22,354	$	496	$	563
Interest cost	26,304		25,449		1,821		1,861		52,609		50,898		3,642		3,722
Expected return on plan assets	(33,856)		(34,598)		(3,510)		(3,487)		(67,713)		(69,194)		(7,020)		(6,972)
Amortization of net actuarial (gain)/losses	65		64		(746)		(706)		130		128		(1,492)		(1,414)
Net periodic pension/benefit cost (return)	2,461		2,093		(2,187)		(2,050)		4,922		4,186		(4,374)		(4,101)
Impact of PUC D&Os	17,800		18,089		2,024		1,887		35,599		36,179		4,049		3,775
Net periodic pension/benefit cost (return) (adjusted for impact of PUC D&Os)	$	20,261	$	20,182	$	(163)	$	(163)	$	40,521	$	40,365	$	(325)	$	(326)
Hawaiian Electric consolidated
Service cost	$	9,705	$	10,916	$	245	$	278	$	19,410	$	21,832	$	490	$	556
Interest cost	25,430		24,627		1,740		1,779		50,859		49,254		3,481		3,558
Expected return on plan assets	(33,052)		(33,775)		(3,461)		(3,434)		(66,101)		(67,552)		(6,923)		(6,868)
Amortization of net actuarial (gain)/losses	24		11		(737)		(694)		47		23		(1,474)		(1,388)
Net periodic pension/benefit cost (return)	2,107		1,779		(2,213)		(2,071)		4,215		3,557		(4,426)		(4,142)
Impact of PUC D&Os	17,800		18,089		2,024		1,887		35,599		36,179		4,049		3,775
Net periodic pension/benefit cost (return) (adjusted for impact of PUC D&Os)	$	19,907	$	19,868	$	(189)	$	(184)	$	39,814	$	39,736	$	(377)	$	(367)