Cash flows (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Supplemental disclosures of cash flow information
Interest paid to non-affiliates	$ 43	$ 42
Income taxes paid	1	6
Supplemental disclosures of noncash activities
Common stock dividends reinvested in HEI common stock	12	12
Increases in common stock related to director and officer compensatory plans	1	4
Additions to electric utility property, plant and equipment - Unpaid invoices and other	5	12
Real estate acquired in settlement of loans	3	5
Loans transferred from held-for-investment to held-for-sale	$ 25