Cover Page - shares	9 Months Ended
	Sep. 30, 2020	Oct. 23, 2020
Entity Information [Line Items]
Document Type	10-Q
Document Quarterly Report	true
Document Period End Date	Sep. 30, 2020
Document Transition Report	false
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
Title of each class	Common Stock, Without Par Value
Trading Symbol	HE
Security Exchange Name	NYSE
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		109,181,124
Entity Registrant Name	HAWAIIAN ELECTRIC INDUSTRIES INC
Entity Central Index Key	0000354707
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3
Hawaiian Electric Company, Inc. and Subsidiaries
Entity Information [Line Items]
Document Type	10-Q
Entity File Number	1-4955
Entity Tax Identification Number	99-0040500
Entity Incorporation, State or Country Code	HI
Entity Address, Address Line One	1001 Bishop Street, Suite, 2500
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	543-7771
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Non-accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
Entity Shell Company	false
Entity Common Stock, Shares Outstanding		17,048,783
Entity Registrant Name	HAWAIIAN ELECTRIC COMPANY INC
Entity Central Index Key	0000046207
Current Fiscal Year End Date	--12-31
Document Fiscal Year Focus	2020
Document Fiscal Period Focus	Q3