Bank segment (HEI only) - Loans Receivable, Narrative (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Bank Segment Disclosure [Abstract]
Percentage of benchmark loan to appraisal ratio in excess of which mortgage insurance is required	80.00%
Minimum benchmark percentage of loan to non-owner occupied residential property purchase	75.00%
Real estate loans for investors	$ 1,500.0	$ 1,500.0	$ 1,300.0
Loans pledged as collateral to secure advances from the FHLB of Des Moines	2,800.0	3,000.0
Loans to directors, executive directors, affiliates and any related interest of such individuals	13.1	13.2
Loan balances, related interests of individuals who are directors	$ 10.0	$ 10.0