Bank segment (HEI only) Statements of Comprehensive Income- Additional Information (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Net unrealized gains (losses) on securities arising during the period, taxes	$ 3,856	$ (9,037)	$ 631
Less: reclassification adjustment for net realized gains included in net income, taxes	(1,132)	(488)	(53)
Net gains (losses) arising during the period, tax benefits	(149,364)	142,478	(63,303)
Less: amortization of net loss, prior service gain and transition obligation included in net periodic benefit cost, tax benefits	7,245	14,870	9,764
American Savings Bank (ASB)
Net unrealized gains (losses) on securities arising during the period, taxes	3,856	(9,037)	631
Less: reclassification adjustment for net realized gains included in net income, taxes	1,132	488	53
Net gains (losses) arising during the period, tax benefits	(6,164)	10,450	(5,240)
Less: amortization of net loss, prior service gain and transition obligation included in net periodic benefit cost, tax benefits	$ (561)	$ (1,187)	$ (684)