Cash flows (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Supplemental disclosures of cash flow information
Interest paid	$ 21	$ 20
Income taxes paid	1	1
Income taxes refunded	47	19
Supplemental disclosures of noncash activities
Increases in common stock related to director and officer compensatory plans	2	1
Real estate acquired in settlement of loans	0	1
Real estate transferred from property, plant and equipment to other assets held-for-sale	5	0
Obligations to fund low income housing investments	0	10
Additions to electric utility property, plant and equipment - unpaid invoices and other	24	9
Hawaiian Electric Company, Inc. and Subsidiaries
Supplemental disclosures of cash flow information
Interest paid	13	13
Income taxes refunded	6	8
Supplemental disclosures of noncash activities
Additions to electric utility property, plant and equipment - unpaid invoices and other	$ 24	$ 9