Condensed Consolidated Statements of Comprehensive Income (unaudited) (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Statement of Comprehensive Income [Abstract]
Net unrealized gains (losses) on securities arising during the period, (taxes) benefits	$ 1,592	$ (1,334)	$ 6,459	$ (1,482)
Reclassification adjustment to net income, tax expense (benefits)	0	0	0	(289)
Amortization of prior service credit and net losses recognized during the period in net periodic benefit cost, taxes (benefits)	(1,862)	(2,508)	(3,654)	(5,010)
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, taxes	1,674	2,281	3,277	4,582
Hawaiian Electric Company, Inc. and Subsidiaries
Reclassification adjustment to net income, tax expense (benefits)	0	0	0	(289)
Amortization of prior service credit and net losses recognized during the period in net periodic benefit cost, taxes (benefits)	(1,683)	(2,306)	(3,297)	(4,610)
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, taxes	$ 1,674	$ 2,281	$ 3,277	$ 4,582