v3.26.1
Cash flows (Details) - USD ($)
$ in Millions
 1 Months Ended 6 Months Ended
Apr. 30, 2026
Jun. 30, 2026
Jun. 30, 2025
Supplemental disclosures of cash flow information      
Interest to non-affiliates, net of amounts capitalized   $ 54 $ 59
Interest on finance lease obligations   22 19
Federal income tax, net   (5) 16
State of Hawaii income tax, net (including refundable credits)   0 (1)
Supplemental disclosures of noncash activities      
Common stock issued (gross) for nonemployee director and executive/management compensation (financing)   2 2
Debt assumed by buyer - sale of a subsidiary (financing)   0 39
Capital contribution from parent related to first installment payment of the Wildfire tort-related claim liability (financing) $ 479    
HEI consolidated and Hawaiian Electric consolidated      
Property, plant and equipment      
Unpaid invoices and accruals for capital expenditures, balance, end of period (investing)   77 58
Right-of-use assets obtained in exchange for finance lease obligations (financing)   0 42
Estimated fair value of noncash contributions in aid of construction (investing)   5 5
Reduction of long-term debt from funds previously transferred for repayment (financing)   0 47
Right-of-use assets obtained in exchange for operating lease obligations (investing)   0 10
Hawaiian Electric Company, Inc. and Subsidiaries      
Supplemental disclosures of cash flow information      
Interest to non-affiliates, net of amounts capitalized   49 41
Interest on finance lease obligations   22 19
Federal income tax, net   (2) 20
State of Hawaii income tax, net (including refundable credits)   2 4
Supplemental disclosures of noncash activities      
Capital contribution from parent related to first installment payment of the Wildfire tort-related claim liability (financing)   479 0
Capital distribution from former unconsolidated affiliate (financing)   287 0
Capital distribution to parent (financing)   49 0
Capital contribution from parent of a membership interest in a former unconsolidated affiliate (financing)   0 $ 287
Property, plant and equipment      
Noncash capital distribution to parent and noncash transfer of operating liabilities from the parent   $ 12