Cash flows (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Supplemental disclosures of cash flow information
Interest paid to non-affiliates, net of amounts capitalized	$ 106	$ 98	$ 98
Income taxes paid (net of refundable credits)	41	41	32
Income taxes refunded (including refundable credits)	2	7	3
Supplemental disclosures of noncash activities
Electric utility property, plant and equipment-Unpaid invoices and accruals for capital expenditures, balance, end of period (investing)	68	48	44
Loans transferred from held for investment to held for sale (investing)	0	61	0
Real estate transferred from property, plant and equipment to other assets held-for-sale (investing)	0	3	0
Right-of-use assets obtained in exchange for operating lease obligations (investing)	51	44	26
Property, plant, equipment and other assets received in exchange for the assumption of debt associated with a business acquisition (investing)	68	0	0
Debt, lease liabilities and other liabilities assumed in business acquisition (financing)	68	0	0
Common stock issued (gross) for director and executive/management compensation (financing)	10	7	16
Obligations to fund low income housing investments, net (investing)	9	36	25
Transfer of securities from available for sale to held to maturities (investing)	755	0	0
Hawaiian Electric Company, Inc. and Subsidiaries
Supplemental disclosures of cash flow information
Interest paid to non-affiliates, net of amounts capitalized	69	71	65
Income taxes paid (net of refundable credits)	67	45	41
Income taxes refunded (including refundable credits)	0	5	3
Supplemental disclosures of noncash activities
Electric utility property, plant and equipment-Unpaid invoices and accruals for capital expenditures, balance, end of period (investing)	64	43	41
Right-of-use assets obtained in exchange for operating lease obligations (investing)	44	44	17
Estimated fair value of noncash contributions in aid of construction (investing)	14	8	10
Increase related to an acquisition (investing)	15	0	0
Right-of-use assets obtained in exchange for finance lease obligations (financing)	48	0	0
Reduction of long-term debt from funds previously transferred for repayment (financing)	$ 0	$ 0	$ 82