Consolidated Balance Sheets - HECO (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Hawaiian Electric Company, Inc. and Subsidiaries
Accumulated depreciation on other property, plant and equipment	$ 1,255	$ 1,251

Amount of accumulated depreciation of long-lived, physical assets used to produce goods and services and not intended for resale, classified as other.

No definition available.

Name:	us-gaap_PropertyPlantAndEquipmentOtherAccumulatedDepreciation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant