Bank segment (HEI only) - Mortgage Servicing Rights, Narrative (Details) - American Savings Bank (ASB) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loans receivable
Repurchased mortgage loans	$ 0	$ 0	$ 500,000
Mortgage servicing fees	$ 2,900,000	3,500,000	3,500,000
Minimum
Loans receivable
Servicing Assets and servicing liabilities, basis spread	0.50%
Maximum
Loans receivable
Servicing Assets and servicing liabilities, basis spread	1.00%
Residential loan
Loans receivable
Proceeds from sale of mortgage loans	$ 236,100,000	275,300,000	155,000,000
Gain on sale of mortgage loans	$ 6,600,000	$ 6,300,000	$ 2,900,000