Consolidated Statements of Comprehensive Income - HECO - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Net income for common stock	$ 66,263	$ 63,419	$ 42,512	$ 45,688	$ 49,573	$ 65,900	$ 46,054	$ 40,247	$ 217,882	$ 201,774	$ 165,297
Other comprehensive income (loss), net of taxes:
Reclassification adjustment to net income, net of tax benefits of nil, nil and $289 for 2019, 2018 and 2017, respectively									0	0	454
Retirement benefit plans:
Net gains (losses) arising during the period, net of (taxes) benefits of $(1,821), $9,024 and $(39,587) for 2019, 2018 and 2017, respectively									10,914	(28,101)	65,531
Adjustment for amortization of prior service credit and net losses recognized during the period in net periodic benefit cost, net of tax benefits of $3,312, $6,594 and $9,221 for 2019, 2018 and 2017, respectively									10,107	21,015	15,737
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of (taxes) benefits of $(5,610), $2,887 and $(49,523) for 2019, 2018 and 2017, respectively									(16,177)	8,325	(78,724)
Other comprehensive income (loss), net of taxes									30,571	(8,669)	(1,372)
Comprehensive income									248,453	193,105	163,925
Hawaiian Electric Company, Inc. and Subsidiaries
Net income for common stock	$ 45,361	$ 46,779	$ 32,574	$ 32,126	$ 35,297	$ 49,712	$ 31,169	$ 27,475	156,840	143,653	119,951
Other comprehensive income (loss), net of taxes:
Reclassification adjustment to net income, net of tax benefits of nil, nil and $289 for 2019, 2018 and 2017, respectively									0	0	454
Retirement benefit plans:
Net gains (losses) arising during the period, net of (taxes) benefits of $(1,821), $9,024 and $(39,587) for 2019, 2018 and 2017, respectively									5,249	(26,019)	63,105
Adjustment for amortization of prior service credit and net losses recognized during the period in net periodic benefit cost, net of tax benefits of $3,312, $6,594 and $9,221 for 2019, 2018 and 2017, respectively									9,550	19,012	14,477
Reclassification adjustment for impact of D&Os of the PUC included in regulatory assets, net of (taxes) benefits of $(5,610), $2,887 and $(49,523) for 2019, 2018 and 2017, respectively									(16,177)	8,325	(78,724)
Other comprehensive income (loss), net of taxes									(1,378)	1,318	(688)
Comprehensive income									$ 155,462	$ 144,971	$ 119,263