v3.26.1
Credit agreements and long-term debt - Narrative (Details)
Jun. 30, 2026
USD ($)
Dec. 31, 2025
USD ($)
Dec. 05, 2025
USD ($)
Sep. 05, 2025
USD ($)
institution
May 17, 2024
USD ($)
May 14, 2023
USD ($)
Revolving Credit Facility            
Debt Instrument [Line Items]            
Credit agreement $ 850,000,000 $ 840,000,000        
Revolving Credit Facility | Hawaiian Electric Company, Inc. and Subsidiaries            
Debt Instrument [Line Items]            
Credit agreement 625,000,000 615,000,000        
HEI Facility            
Debt Instrument [Line Items]            
Number of financial institutions | institution       8    
Credit agreement       $ 300,000,000   $ 175,000,000
HEI Facility | Letter of Credit            
Debt Instrument [Line Items]            
Credit agreement       25,000,000    
HEI Facility | Bridge Loan            
Debt Instrument [Line Items]            
Credit agreement       30,000,000    
Hawaiian Electric Facility            
Debt Instrument [Line Items]            
Credit agreement       300,000,000   $ 200,000,000
Accordion feature, increase limit       75,000,000    
Hawaiian Electric Facility | Letter of Credit | Hawaiian Electric Company, Inc. and Subsidiaries            
Debt Instrument [Line Items]            
Credit agreement     $ 75,000,000      
Short-term borrowings, net     $ 0      
Hawaiian Electric Facility | Letter of Credit            
Debt Instrument [Line Items]            
Credit agreement       40,000,000    
Hawaiian Electric Facility | Bridge Loan            
Debt Instrument [Line Items]            
Credit agreement       $ 30,000,000    
ABL Credit Facility Agreement | Revolving Credit Facility | Hawaiian Electric Company, Inc. and Subsidiaries            
Debt Instrument [Line Items]            
Credit agreement $ 250,000,000 $ 240,000,000        
ABL Credit Facility Agreement | Revolving Credit Facility | Hawaiian Electric Company, Inc. and Subsidiaries | Line of Credit            
Debt Instrument [Line Items]            
Credit agreement         $ 250,000,000