Bank segment (HEI only) - Loans Receivable, Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Bank Segment Disclosure [Abstract]
Percentage of benchmark loan to appraisal ratio in excess of which mortgage insurance is required	80.00%
Real estate loans for investors	$ 1,200.0	$ 1,500.0	$ 1,400.0
Loans pledged as collateral to secure advances from the FHLB of Seattle	2,400.0	2,300.0
Loans to directors, executive directors, affiliates and any related interest of such individuals	22.9	27.8
Lines of credit closed and repaid, net of new loans and lines of credit to executive directors	4.9
Lines of credit closed and repaid	4.9
Loan balances, related interests of individuals who are directors	$ 19.0	$ 25.8