Cash flows (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Supplemental disclosures of cash flow information
Interest paid to non-affiliates	$ 84,000,000	$ 85,000,000	$ 84,000,000
Income taxes paid	47,000,000	18,000,000	17,000,000
Income taxes refunded	24,000,000	4,000,000	31,000,000
Supplemental disclosures of noncash activities
Common stock dividends reinvested in HEI common stock	0	24,000,000	24,000,000
Increases in common stock related to director and officer compensatory plans	6,000,000	5,000,000	6,000,000
Loans transferred from held for investment to held for sale	0	25,000,000	0
Real estate acquired in settlement of loans	3,000,000	4,000,000	11,000,000
Obligations to fund low income housing investments, net	14,000,000	1,000,000	0
Electric utility property, plant and equipment
AFUDC-equity	6,771,000	5,561,000	7,007,000
Unpaid invoices and other	68,000,000	24,000,000	37,000,000
Hawaiian Electric Company, Inc. and Subsidiaries
Supplemental disclosures of cash flow information
Interest paid to non-affiliates	61,000,000	59,000,000	57,000,000
Income taxes paid	6,000,000	6,000,000	6,000,000
Income taxes refunded	8,000,000	32,000,000	9,000,000
Electric utility property, plant and equipment
AFUDC-equity	6,771,000	5,561,000	7,007,000
Estimated fair value of noncash contributions in aid of construction	3,000,000	5,000,000	10,000,000
Unpaid invoices and other	$ 65,000,000	$ 24,000,000	$ 37,000,000