XML 18 R1.htm IDEA: XBRL DOCUMENT v3.10.0.1
Document and Entity Information - shares
 6 Months Ended
Jun. 30, 2018
Jul. 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 Jun. 30, 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   108,879,245
Document Fiscal Year Focus 2018  
Document Fiscal Period Focus Q2  
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 Jun. 30, 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 Q2