SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF REGISTRANT - BALANCE SHEETS (Details) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Assets
Cash and cash equivalents	$ 169,208	$ 261,881	$ 278,452	$ 300,478
Accounts receivable	325,672	263,209
Property, plant and equipment, net	4,830,118	4,460,248
Other assets	530,364	513,535
Total assets	13,104,051	12,534,160	11,881,981
Liabilities
Accounts payable	214,773	193,714
Long-term debt, net	1,879,641	1,683,797
Other	580,788	521,018
Total liabilities	10,907,478	10,402,481
Shareholders' equity
Preferred stock, no par value, authorized 10,000,000 shares; issued: none	0	0
Common stock equity	1,669,267	1,662,491
Retained earnings	543,623	476,836
Accumulated other comprehensive loss	(50,610)	(41,941)
Total shareholders’ equity	2,162,280	2,097,386	2,066,753	1,927,640
Total capitalization and liabilities	$ 13,104,051	$ 12,534,160
Preferred stock, authorized shares	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Common stock, authorized shares	200,000,000	200,000,000
Common stock, issued shares	108,879,245	108,787,807
Common stock, outstanding shares	108,879,245	108,787,807
Hawaiian Electric Industries, Inc.
Assets
Cash and cash equivalents	$ 3,742	$ 11,702	$ 14,924	$ 55,116
Accounts receivable	2,604	2,347
Notes receivable	20,789	0
Property, plant and equipment, net	3,456	3,910
Deferred income tax assets	10,147	8,710
Other assets	11,963	15,480
Investments in subsidiaries, at equity	2,605,038	2,466,342
Total assets	2,657,739	2,508,491
Liabilities
Accounts payable	2,001	561
Interest payable	3,476	2,319
Notes payable to subsidiaries	34	1,918
Commercial paper	48,992	62,993
Short-term debt, net	0	49,953
Long-term debt, net	398,874	249,588
Retirement benefits liability	29,565	31,518
Other	12,517	12,255
Total liabilities	495,459	411,105
Shareholders' equity
Preferred stock, no par value, authorized 10,000,000 shares; issued: none	0	0
Common stock equity	1,669,267	1,662,491
Retained earnings	543,623	476,836
Accumulated other comprehensive loss	(50,610)	(41,941)
Total shareholders’ equity	2,162,280	2,097,386
Total capitalization and liabilities	$ 2,657,739	$ 2,508,491
Preferred stock, authorized shares	10,000,000	10,000,000
Preferred stock, shares issued	0	0
Common stock, authorized shares	200,000,000	200,000,000
Common stock, issued shares	108,879,245	108,787,807
Common stock, outstanding shares	108,879,245	108,787,807