Bank segment (HEI only) - Reconciliation of Income (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Gain on sales of investment securities, net and equity-method investment	$ 8,123	$ 528	$ 9,275
Total revenues	3,741,985	2,850,379	2,579,775
Total interest expense	116,703	99,403	99,808
Less: Retirement defined benefits expense (credit)—other than service costs	(4,411)	(5,848)	3,210
Total expenses	3,360,912	2,464,313	2,268,282
Operating income	381,073	386,066	311,493
Add back: Retirement defined benefits expense (credit)—other than service costs	(4,411)	(5,848)	3,210
Add back: Gain on sale of investment securities, net	8,123	528	9,275
Income before income taxes	304,195	310,863	240,624
American Savings Bank (ASB)
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Effects of Changes, Net [Line Items]
Interest and dividend income	265,874	242,266	244,663
Noninterest income	56,972	64,660	78,123
Less: Gain on sale of real estate	1,778	0	0
Gain on sales of investment securities, net and equity-method investment	0	528	9,275
Total revenues	321,068	306,398	313,511
Total interest expense	13,301	5,040	11,114
Provision for credit losses	2,037	(25,825)	50,811
Noninterest expense	205,267	197,152	191,590
Less: Retirement defined benefits expense (credit)—other than service costs	(723)	(1,828)	1,813
Gain on sale of real estate	1,778	0	0
Total expenses	219,550	178,195	251,702
Operating income	101,518	128,203	61,809
Add back: Retirement defined benefits expense (credit)—other than service costs	(723)	(1,828)	1,813
Add back: Gain on sale of investment securities, net	0	528	9,275
Income before income taxes	$ 102,241	$ 130,559	$ 69,271