| Cover | Oct. 30, 2019 |
| Cover page. | |
| Document Type | 8-K |
| Document Period End Date | Oct. 30, 2019 |
| Entity Registrant Name | Hawaiian Electric Industries, Inc. |
| Entity File Number | 1-8503 |
| Entity Tax Identification Number | 99-0208097 |
| Entity Incorporation, State or Country Code | HI |
| Entity Address, Address Line One | 1001 Bishop Street, Suite 2900 |
| Entity Address, City or Town | Honolulu |
| Entity Address, State or Province | HI |
| Entity Address, Postal Zip Code | 96813 |
| City Area Code | 808 |
| Local Phone Number | 543-5662 |
| Written Communications | false |
| Soliciting Material | false |
| Pre-commencement Tender Offer | false |
| Pre-commencement Issuer Tender Offer | false |
| Title of each class | Common Stock, Without Par Value |
| Trading Symbol | HE |
| Security Exchange Name | NYSE |
| Entity Emerging Growth Company | false |
| Entity Central Index Key | 0000354707 |
| Amendment Flag | false |
