Consolidated Statements of Income - HECO - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Revenues									$ 2,614,831		$ 2,380,654
Expenses
Purchased power									639,000	$ 587,000	563,000
Total expenses									2,527,493	2,209,392	2,024,816
Operating income	$ 84,604	$ 98,064	$ 78,799	$ 71,889	$ 87,220	$ 111,473	$ 77,802	$ 69,738	333,356	346,233	355,838
Allowance for equity funds used during construction									10,877	12,483	8,325
Retirement defined benefits expense—other than service costs									(5,962)	(7,942)	(7,663)
Allowance for borrowed funds used during construction									4,867	4,778	3,144
Income before income taxes									254,461	276,580	373,841
Income taxes									50,797	109,393	123,695
Net income (loss)	50,046	66,371	46,527	40,720	32,843	60,544	39,134	34,666	203,664	167,187	250,146
Preferred stock dividends of subsidiaries									1,890	1,890	1,890
Net income for common stock	49,573	65,900	46,054	40,247	32,370	60,073	38,661	34,193	201,774	165,297	248,256
Hawaiian Electric Company, Inc. and Subsidiaries
Revenues									2,546,525	2,257,566	2,094,368
Expenses
Fuel oil									760,528	587,768	454,704
Purchased power									639,307	586,634	562,740
Other operation and maintenance									461,491	411,907	399,931
Depreciation									203,626	192,784	187,061
Taxes, other than income taxes									239,912	214,949	199,862
Total expenses									2,304,864	1,994,042	1,804,298
Operating income	61,112	74,036	55,144	51,369	68,184	88,497	56,482	50,361	241,661	263,524	290,070
Allowance for equity funds used during construction									10,877	12,483	8,325
Retirement defined benefits expense—other than service costs									(3,631)	(6,003)	(5,602)
Interest expense and other charges, net									(73,348)	(69,637)	(66,824)
Allowance for borrowed funds used during construction									4,867	4,778	3,144
Income before income taxes									180,426	205,145	229,113
Income taxes									34,778	83,199	84,801
Net income (loss)	35,796	50,210	31,668	27,974	25,854	47,985	26,143	21,964	145,648	121,946	144,312
Preferred stock dividends of subsidiaries									915	915	915
Net income attributable to Hawaiian Electric									144,733	121,031	143,397
Preferred stock dividends of Hawaiian Electric									1,080	1,080	1,080
Net income for common stock	$ 35,297	$ 49,712	$ 31,169	$ 27,475	$ 25,355	$ 47,487	$ 25,644	$ 21,465	$ 143,653	$ 119,951	$ 142,317