SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF REGISTRANT- BALANCE SHEETS (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets [Abstract]
Cash and cash equivalents	$ 300,478,000	$ 175,542,000	$ 220,036,000	$ 219,662,000
Accounts receivable	242,766,000	313,696,000
Property, plant and equipment, net	4,377,658,000	4,148,774,000
Other assets	488,635,000	542,523,000
Total assets	11,790,196,000	11,185,142,000	10,340,906,000
Liabilities
Accounts payable	138,523,000	186,425,000
Long-term debt	1,586,546,000	1,506,546,000
Other	471,828,000	531,230,000
Total liabilities	9,828,263,000	9,360,276,000
Shareholders' equity
Preferred stock, no par value, authorized 10,000,000 shares; issued: none	0	0
Common stock equity	1,629,136,000	1,521,297,000
Retained earnings	324,766,000	296,654,000	255,030,000	215,947,000
Accumulated other comprehensive loss	(26,262,000)	(27,378,000)	(16,750,000)	(26,423,000)
Total shareholders' equity	1,927,640,000	1,790,573,000	1,726,406,000	1,593,008,000
Total capitalization and liabilities	$ 11,790,196,000	$ 11,185,142,000
Aggregate principal payments
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	107,460,406	102,565,266
Common stock, outstanding shares	107,460,406	102,565,266
Self-insured United States longshore & Harbor bond
Aggregate principal payments
Guarantee obligation maximum exposure	$ 200,000
Self-insured automobile bond
Aggregate principal payments
Guarantee obligation maximum exposure	$ 600,000
HEI Term loan LIBOR .75% (effective October 8, 2015), due 2017 | LIBOR
Aggregate principal payments
Line of credit facility basis point spread (as a percent)	0.75%
HEI senior note 4.41%, due 2016
Shareholders' equity
Interest rate of medium-term notes (as a percent)	4.41%	4.41%
HEI senior note 5.67%, due 2021
Shareholders' equity
Interest rate of medium-term notes (as a percent)	5.67%	5.67%
HEI senior note 3.99%, due 2023
Shareholders' equity
Interest rate of medium-term notes (as a percent)	3.99%	3.99%
Hawaiian Electric Industries, Inc.
Assets [Abstract]
Cash and cash equivalents	$ 55,116,000	$ 276,000	$ 571,000	$ 18,021,000
Accounts receivable	5,459,000	1,991,000
Property, plant and equipment, net	4,514,000	4,917,000
Deferred income tax assets	16,715,000	15,922,000
Other assets	11,984,000	11,070,000
Investments in subsidiaries, at equity	2,293,679,000	2,223,597,000
Total assets	2,387,467,000	2,257,773,000
Liabilities
Accounts payable	1,254,000	1,993,000
Interest payable	2,450,000	2,583,000
Notes payable to subsidiaries	5,946,000	7,857,000
Commercial paper	103,063,000	118,972,000
Long-term debt	300,000,000	300,000,000
Retirement benefits liability	31,704,000	32,030,000
Other	15,410,000	3,765,000
Total liabilities	459,827,000	467,200,000
Shareholders' equity
Preferred stock, no par value, authorized 10,000,000 shares; issued: none	0	0
Common stock equity	1,629,136,000	1,521,297,000
Retained earnings	324,766,000	296,654,000
Accumulated other comprehensive loss	(26,262,000)	(27,378,000)
Total shareholders' equity	1,927,640,000	1,790,573,000
Total capitalization and liabilities	2,387,467,000	$ 2,257,773,000
Aggregate principal payments
2016	75,000,000
2017	125,000,000
2018	0
2019	0
2020	$ 0
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	107,460,406	102,565,266
Common stock, outstanding shares	107,460,406	102,565,266
Hawaiian Electric Industries, Inc. | HEI Term loan LIBOR .75% (effective October 8, 2015), due 2017
Liabilities
Long-term debt	$ 125,000,000	$ 125,000,000
Hawaiian Electric Industries, Inc. | HEI senior note 4.41%, due 2016
Liabilities
Long-term debt	$ 75,000,000	$ 75,000,000
Shareholders' equity
Interest rate of medium-term notes (as a percent)	4.41%	4.41%
Hawaiian Electric Industries, Inc. | HEI senior note 5.67%, due 2021
Liabilities
Long-term debt	$ 50,000,000	$ 50,000,000
Shareholders' equity
Interest rate of medium-term notes (as a percent)	5.67%	5.67%
Hawaiian Electric Industries, Inc. | HEI senior note 3.99%, due 2023
Liabilities
Long-term debt	$ 50,000,000	$ 50,000,000
Shareholders' equity
Interest rate of medium-term notes (as a percent)	3.99%	3.99%