Cash flows (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Supplemental disclosures of cash flow information
Interest paid	$ 41	$ 44
Income taxes paid	35	22
Income taxes refunded	55	24
Supplemental disclosures of noncash activities
Real estate acquired in settlement of loans (investing)	0	2
Real estate transferred from property, plant and equipment to other assets held-for-sale (investing)	5	0
Obligations to fund low income housing investments (operating)	0	8
Hawaiian Electric Company, Inc. and Subsidiaries
Supplemental disclosures of cash flow information
Interest paid	30	31
Income taxes paid	9	6
Income taxes refunded	12	8
Supplemental disclosures of noncash activities
Additions to electric utility property, plant and equipment - unpaid invoices and accruals, as restated (1)	$ (12)	$ 3