XML 35 R1.htm IDEA: XBRL DOCUMENT v3.8.0.1
Document and Entity Information - USD ($)
 12 Months Ended
Dec. 31, 2017
Feb. 13, 2018
Jun. 30, 2017
Entity Information [Line Items]      
Entity Registrant Name HAWAIIAN ELECTRIC INDUSTRIES INC    
Entity Central Index Key 0000354707    
Document Type 10-K    
Document Period End Date Dec. 31, 2017    
Amendment Flag false    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer Yes    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Large Accelerated Filer    
Entity Public Float     $ 3,522,474,037
Entity Common Stock, Shares Outstanding   108,841,157  
Document Fiscal Year Focus 2017    
Document Fiscal Period Focus FY    
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-K    
Document Period End Date Dec. 31, 2017    
Amendment Flag false    
Current Fiscal Year End Date --12-31    
Entity Well-known Seasoned Issuer No    
Entity Voluntary Filers No    
Entity Current Reporting Status Yes    
Entity Filer Category Non-accelerated Filer    
Entity Public Float     $ 0
Entity Common Stock, Shares Outstanding   16,142,216  
Document Fiscal Year Focus 2017    
Document Fiscal Period Focus FY