Condensed Consolidated Statements of Changes in Shareholders' Equity and Common Stock Equity (unaudited) - USD ($) $ in Thousands	Total	Hawaiian Electric Company, Inc. and Subsidiaries	Common stock	Common stock Hawaiian Electric Company, Inc. and Subsidiaries	Premium on capital stock Hawaiian Electric Company, Inc. and Subsidiaries	Retained Earnings	Retained Earnings Hawaiian Electric Company, Inc. and Subsidiaries	Accumulated other comprehensive income (loss)	Accumulated other comprehensive income (loss) Hawaiian Electric Company, Inc. and Subsidiaries
Beginning Balance at Dec. 31, 2017	$ 2,097,386	$ 1,845,283	$ 1,662,491	$ 107,634	$ 614,675	$ 476,836	$ 1,124,193	$ (41,941)	$ (1,219)
Beginning Balance (in shares) at Dec. 31, 2017			108,788,000	16,142,000
Increase (decrease) in stockholders' equity
Net income for common stock	40,247	27,475				40,247	27,475
Other comprehensive income (loss), net of tax (benefits)	(12,773)	31						(12,773)	31
Share-based expenses and other, net	658		$ 658
Share-based expenses and other, net (in shares)			53,000
Common stock dividends	(33,741)	(25,826)				(33,741)	(25,826)
Common stock issuance expenses		(8)			(8)
Ending Balance at Mar. 31, 2018	2,091,777	1,846,955	$ 1,663,149	$ 107,634	614,667	483,342	1,125,842	(54,714)	(1,188)
Ending Balance (in shares) at Mar. 31, 2018			108,841,000	16,142,000
Beginning Balance at Dec. 31, 2017	2,097,386	1,845,283	$ 1,662,491	$ 107,634	614,675	476,836	1,124,193	(41,941)	(1,219)
Beginning Balance (in shares) at Dec. 31, 2017			108,788,000	16,142,000
Increase (decrease) in stockholders' equity
Net income for common stock	152,201	108,356
Other comprehensive income (loss), net of tax (benefits)	(21,187)	85						(21,187)
Common stock dividends		(77,479)
Common stock issuance expenses		(8)
Ending Balance at Sep. 30, 2018	2,132,045	1,876,237	$ 1,667,371	$ 107,634	614,667	527,802	1,155,070	(63,128)	(1,134)
Ending Balance (in shares) at Sep. 30, 2018			108,879,000	16,142,000
Beginning Balance at Mar. 31, 2018	2,091,777	1,846,955	$ 1,663,149	$ 107,634	614,667	483,342	1,125,842	(54,714)	(1,188)
Beginning Balance (in shares) at Mar. 31, 2018			108,841,000	16,142,000
Increase (decrease) in stockholders' equity
Net income for common stock	46,054	31,169				46,054	31,169
Other comprehensive income (loss), net of tax (benefits)	(3,825)	26						(3,825)	26
Share-based expenses and other, net	2,752		$ 2,752
Share-based expenses and other, net (in shares)			38,000
Common stock dividends	(33,740)	(25,826)				(33,740)	(25,826)
Ending Balance at Jun. 30, 2018	2,103,018	1,852,324	$ 1,665,901	$ 107,634	614,667	495,656	1,131,185	(58,539)	(1,162)
Ending Balance (in shares) at Jun. 30, 2018			108,879,000	16,142,000
Increase (decrease) in stockholders' equity
Net income for common stock	65,900	49,712				65,900	49,712
Other comprehensive income (loss), net of tax (benefits)	(4,589)	28						(4,589)	28
Share-based expenses and other, net	1,470		$ 1,470
Share-based expenses and other, net (in shares)			0
Common stock dividends	(33,754)	(25,827)				(33,754)	(25,827)
Ending Balance at Sep. 30, 2018	2,132,045	1,876,237	$ 1,667,371	$ 107,634	614,667	527,802	1,155,070	(63,128)	(1,134)
Ending Balance (in shares) at Sep. 30, 2018			108,879,000	16,142,000
Beginning Balance at Dec. 31, 2018	$ 2,162,280	1,957,641	$ 1,669,267	$ 111,696	681,305	543,623	1,164,541	(50,610)	99
Beginning Balance (in shares) at Dec. 31, 2018	108,879,245		108,879,000	16,751,000
Increase (decrease) in stockholders' equity
Net income for common stock	$ 45,688	32,126				45,688	32,126
Other comprehensive income (loss), net of tax (benefits)	9,241	24						9,241	24
Share-based expenses and other, net	1,166		$ 1,166
Share-based expenses and other, net (in shares)			58,000
Common stock dividends	(34,860)	(25,313)				(34,860)	(25,313)
Ending Balance at Mar. 31, 2019	2,183,515	1,964,478	$ 1,670,433	$ 111,696	681,305	554,451	1,171,354	(41,369)	123
Ending Balance (in shares) at Mar. 31, 2019			108,937,000	16,751,000
Beginning Balance at Dec. 31, 2018	$ 2,162,280	1,957,641	$ 1,669,267	$ 111,696	681,305	543,623	1,164,541	(50,610)	99
Beginning Balance (in shares) at Dec. 31, 2018	108,879,245		108,879,000	16,751,000
Increase (decrease) in stockholders' equity
Net income for common stock	$ 151,619	111,479
Other comprehensive income (loss), net of tax (benefits)	26,237	73						26,237
Common stock dividends		(75,939)
Common stock issuance expenses		0
Ending Balance at Sep. 30, 2019	$ 2,242,689	1,993,254	$ 1,676,411	$ 111,696	681,305	590,651	1,200,081	(24,373)	172
Ending Balance (in shares) at Sep. 30, 2019	108,972,564		108,973,000	16,751,000
Beginning Balance at Mar. 31, 2019	$ 2,183,515	1,964,478	$ 1,670,433	$ 111,696	681,305	554,451	1,171,354	(41,369)	123
Beginning Balance (in shares) at Mar. 31, 2019			108,937,000	16,751,000
Increase (decrease) in stockholders' equity
Net income for common stock	42,512	32,574				42,512	32,574
Other comprehensive income (loss), net of tax (benefits)	13,699	23						13,699	23
Share-based expenses and other, net	3,720		$ 3,720
Share-based expenses and other, net (in shares)			35,000
Common stock dividends	(34,860)	(25,313)				(34,860)	(25,313)
Ending Balance at Jun. 30, 2019	2,208,586	1,971,762	$ 1,674,153	$ 111,696	681,305	562,103	1,178,615	(27,670)	146
Ending Balance (in shares) at Jun. 30, 2019			108,972,000	16,751,000
Increase (decrease) in stockholders' equity
Net income for common stock	63,419	46,779				63,419	46,779
Other comprehensive income (loss), net of tax (benefits)	3,297	26						3,297	26
Share-based expenses and other, net	2,258		$ 2,258
Share-based expenses and other, net (in shares)			1,000
Common stock dividends	(34,871)	(25,313)				(34,871)	(25,313)
Ending Balance at Sep. 30, 2019	$ 2,242,689	$ 1,993,254	$ 1,676,411	$ 111,696	$ 681,305	$ 590,651	$ 1,200,081	$ (24,373)	$ 172
Ending Balance (in shares) at Sep. 30, 2019	108,972,564		108,973,000	16,751,000