Cash flows (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Supplemental disclosures of cash flow information
Interest paid to non-affiliates, net of amounts capitalized	$ 107,000	$ 102,000	$ 83,000
Income taxes paid (including refundable credits)	56,000	72,000	55,000
Income taxes refunded (including refundable credits)	4,000	34,000	1,000
Supplemental disclosures of noncash activities
Unpaid invoices and accruals for capital expenditures (investing), Balance, end of period	64,000	59,000	38,000
Loans transferred from held for investment to held for sale (investing)	0	1,000	41,000
Common stock issued (gross) for director and executive/management compensation (financing)	5,000	4,000	11,000
Obligations to fund low income housing investments, net (investing)	11,000	12,000	13,000
Transfer of retail repurchase agreements to deposit liabilities (financing)	0	102,000	0
Hawaiian Electric Company, Inc. and Subsidiaries
Supplemental disclosures of cash flow information
Interest paid to non-affiliates, net of amounts capitalized	68,000	73,000	63,000
Income taxes paid (including refundable credits)	55,000	64,000	26,000
Income taxes refunded (including refundable credits)	4,000	31,000	0
Supplemental disclosures of noncash activities
Unpaid invoices and accruals for capital expenditures (investing), Balance, end of period	62,000	44,000	38,000
Estimated fair value of noncash contributions in aid of construction (investing)	9,000	14,000	18,000
Acquisition of Hawaiian Telcom’s interest in joint poles (investing)	$ 0	$ 48	$ 0