Bank segment (HEI only) - Available For Sale Investment Securities (Details) $ in Thousands	Dec. 31, 2021 USD ($) issue	Dec. 31, 2020 USD ($) issue
Available-for-sale
Available-for-sale investment securities	$ 2,574,618	$ 1,970,417
Held-to-maturity
Amortized cost	522,270	226,947
Held-to-maturity investment securities	510,474
American Savings Bank (ASB)
Available-for-sale
Amortized cost	2,618,384	1,943,114
Gross unrealized gains	7,969	30,454
Gross unrealized losses	(51,735)	(3,151)
Available-for-sale investment securities	$ 2,574,618	$ 1,970,417
Number of issues, less than 12 months \| issue	125	22
Fair value, less than 12 months	$ 1,902,850	$ 373,924
Gross unrealized losses, less than 12 months	$ (38,850)	$ (3,151)
Number of issues, more than 12 months \| issue	18	0
Fair value, 12 months or longer	$ 271,012	$ 0
Gross unrealized losses, 12 months or longer	(12,885)	0
Held-to-maturity
Amortized cost	522,270	226,947
Gross unrealized gains	1,648	3,846
Gross unrealized losses	(13,444)	(830)
Held-to-maturity investment securities	$ 510,474	$ 229,963
Number of issues, less than 12 months \| issue	24	7
Fair value, less than 12 months	$ 330,477	$ 114,152
Gross unrealized losses, less than 12 months	$ (7,835)	$ (830)
Number of issues, more than 12 months \| issue	7	0
Fair value, 12 months or longer	$ 106,483	$ 0
Gross unrealized losses, 12 months or longer	(5,609)	0
American Savings Bank (ASB) \| U.S. Treasury and federal agency obligations
Available-for-sale
Amortized cost	89,714	60,260
Gross unrealized gains	803	2,062
Gross unrealized losses	(427)	0
Available-for-sale investment securities	$ 90,090	$ 62,322
Number of issues, less than 12 months \| issue	4	0
Fair value, less than 12 months	$ 44,827	$ 0
Gross unrealized losses, less than 12 months	$ (427)	$ 0
Number of issues, more than 12 months \| issue	0	0
Fair value, 12 months or longer	$ 0	$ 0
Gross unrealized losses, 12 months or longer	0	0
Held-to-maturity
Amortized cost	59,871
Gross unrealized gains	168
Gross unrealized losses	(170)
Held-to-maturity investment securities	$ 59,869
Number of issues, less than 12 months \| issue	2
Fair value, less than 12 months	$ 39,594
Gross unrealized losses, less than 12 months	$ (170)
Number of issues, more than 12 months \| issue	0
Fair value, 12 months or longer	$ 0
Gross unrealized losses, 12 months or longer	0
American Savings Bank (ASB) \| Mortgage-backed securities — issued or guaranteed by U.S. Government agencies or sponsored agencies
Available-for-sale
Amortized cost	2,482,618	1,825,893
Gross unrealized gains	6,511	26,817
Gross unrealized losses	(51,206)	(3,151)
Available-for-sale investment securities	$ 2,437,923	$ 1,849,559
Number of issues, less than 12 months \| issue	120	22
Fair value, less than 12 months	$ 1,845,243	$ 373,924
Gross unrealized losses, less than 12 months	$ (38,321)	$ (3,151)
Number of issues, more than 12 months \| issue	18	0
Fair value, 12 months or longer	$ 271,012	$ 0
Gross unrealized losses, 12 months or longer	(12,885)	0
Held-to-maturity
Amortized cost	462,399	226,947
Gross unrealized gains	1,480	3,846
Gross unrealized losses	(13,274)	(830)
Held-to-maturity investment securities	$ 450,605	$ 229,963
Number of issues, less than 12 months \| issue	22	7
Fair value, less than 12 months	$ 290,883	$ 114,152
Gross unrealized losses, less than 12 months	$ (7,665)	$ (830)
Number of issues, more than 12 months \| issue	7	0
Fair value, 12 months or longer	$ 106,483	$ 0
Gross unrealized losses, 12 months or longer	(5,609)	0
American Savings Bank (ASB) \| Corporate bonds
Available-for-sale
Amortized cost	30,625	29,776
Gross unrealized gains	655	1,575
Gross unrealized losses	(102)	0
Available-for-sale investment securities	$ 31,178	$ 31,351
Number of issues, less than 12 months \| issue	1	0
Fair value, less than 12 months	$ 12,780	$ 0
Gross unrealized losses, less than 12 months	$ (102)	$ 0
Number of issues, more than 12 months \| issue	0	0
Fair value, 12 months or longer	$ 0	$ 0
Gross unrealized losses, 12 months or longer	0	0
American Savings Bank (ASB) \| Mortgage revenue bonds
Available-for-sale
Amortized cost	15,427	27,185
Gross unrealized gains	0	0
Gross unrealized losses	0	0
Available-for-sale investment securities	$ 15,427	$ 27,185
Number of issues, less than 12 months \| issue	0	0
Fair value, less than 12 months	$ 0	$ 0
Gross unrealized losses, less than 12 months	$ 0	$ 0
Number of issues, more than 12 months \| issue	0	0
Fair value, 12 months or longer	$ 0	$ 0
Gross unrealized losses, 12 months or longer	$ 0	$ 0

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