Document and Entity Information - shares	3 Months Ended
	Mar. 31, 2018	Apr. 27, 2018
Entity Information [Line Items]
Entity Registrant Name	HAWAIIAN ELECTRIC INDUSTRIES INC
Entity Central Index Key	0000354707
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		108,841,348
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1
Hawaiian Electric Company, Inc. and Subsidiaries
Entity Information [Line Items]
Entity Registrant Name	HAWAIIAN ELECTRIC COMPANY INC
Entity Central Index Key	0000046207
Document Type	10-Q
Document Period End Date	Mar. 31, 2018
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Non-accelerated Filer
Entity Common Stock, Shares Outstanding		16,142,216
Document Fiscal Year Focus	2018
Document Fiscal Period Focus	Q1