Consolidated Statements of Income - HECO Statement - 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
Revenues	$ 725,966	$ 771,535	$ 715,485	$ 661,615	$ 761,650	$ 768,048	$ 685,277	$ 645,874	$ 2,874,601	$ 2,860,849	$ 2,555,625
Expenses
Total expenses									2,525,927	2,527,493	2,209,392
Operating income	100,795	97,308	72,634	77,937	84,604	98,064	78,799	71,889	348,674	333,356	346,233
Allowance for equity funds used during construction									11,987	10,877	12,483
Retirement defined benefits expense—other than service costs									(2,806)	(5,962)	(7,942)
Allowance for borrowed funds used during construction									4,453	4,867	4,778
Income before income taxes									271,409	254,461	276,580
Income taxes									51,637	50,797	109,393
Net income (loss)	66,736	63,890	42,985	46,161	50,046	66,371	46,527	40,720	219,772	203,664	167,187
Preferred stock dividends of subsidiaries									1,890	1,890	1,890
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
Hawaiian Electric Company, Inc. and Subsidiaries
Revenues	645,333	688,330	633,784	578,495	680,563	687,409	608,126	570,427	2,545,942	2,546,525	2,257,566
Expenses
Fuel oil									720,709	760,528	587,768
Purchased power									633,256	639,307	586,634
Other operation and maintenance									481,737	461,491	411,907
Depreciation									215,731	203,626	192,784
Taxes, other than income taxes									240,131	239,912	214,949
Total expenses									2,291,564	2,304,864	1,994,042
Operating income	70,331	71,793	55,694	56,560	61,112	74,036	55,144	51,369	254,378	241,661	263,524
Allowance for equity funds used during construction									11,987	10,877	12,483
Retirement defined benefits expense—other than service costs									(2,836)	(3,631)	(6,003)
Interest expense and other charges, net									(70,842)	(73,348)	(69,637)
Allowance for borrowed funds used during construction									4,453	4,867	4,778
Income before income taxes									197,140	180,426	205,145
Income taxes									38,305	34,778	83,199
Net income (loss)	45,860	47,277	33,073	32,625	35,796	50,210	31,668	27,974	158,835	145,648	121,946
Preferred stock dividends of subsidiaries									915	915	915
Net income attributable to Hawaiian Electric									157,920	144,733	121,031
Preferred stock dividends of Hawaiian Electric									1,080	1,080	1,080
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