Condensed Consolidated Statements of Comprehensive Income (unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Statement of Comprehensive Income [Abstract]
Net unrealized gains (losses) on securities arising during the period, taxes (benefits)	$ (4,867)	$ 148
Reclassification adjustment to net income, tax expense (benefits)	0	(289)
Amortization of prior service credit and net losses recognized during the period in net periodic benefit cost, taxes (benefits)	(1,792)	(2,502)
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, taxes	1,603	2,301
Hawaiian Electric Company, Inc. and Subsidiaries
Reclassification adjustment to net income, tax expense (benefits)	0	(289)
Amortization of prior service credit and net losses recognized during the period in net periodic benefit cost, taxes (benefits)	(1,614)	(2,304)
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, taxes	$ 1,603	$ 2,301