SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF REGISTRANT- Balance Sheets (Details) - USD ($)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
ASSETS
Cash and cash equivalents	$ 175,542,000	$ 220,036,000	[1]	$ 219,662,000	[1]	$ 270,265,000	[1]
Accounts receivable	313,696,000	346,785,000
Property, plant and equipment, net	4,148,774,000	3,865,514,000
Other assets	541,542,000	512,627,000
Total assets	11,184,161,000	10,340,044,000
Liabilities
Accounts payable	186,425,000	212,331,000
Long-term debt	1,506,546,000	1,492,945,000
Retirement benefits liability	632,845,000	288,539,000
Other	531,230,000	524,224,000
Total liabilities	9,358,440,000	8,578,681,000
Shareholders' equity
Preferred stock, no par value, authorized 10,000,000 shares; issued: none	0	0
Common stock, no par value, authorized 200,000,000 shares; issued and outstanding: 102,565,266 shares and 101,259,800 shares at December 31, 2014 and 2013, respectively	1,521,297,000	1,488,126,000
Retained earnings	297,509,000	255,694,000
Accumulated other comprehensive loss	(27,378,000)	(16,750,000)		(26,423,000)		(19,137,000)
Total shareholders' equity	1,791,428,000	1,727,070,000		1,593,865,000		1,528,706,000
Total liabilities and shareholders' equity	11,184,161,000	$ 10,340,044,000
Aggregate principal payments
2015	0
2016	200,000,000
2017	0
2018	50,000,000
2019	$ 0
Preferred stock, authorized shares	10,000,000	10,000,000
Common stock, authorized shares	200,000,000	200,000,000
Common stock, issued shares	102,565,266	101,259,800
Common stock, outstanding shares	102,565,266	101,259,800
Deferred income taxes	$ 631,734,000	$ 529,260,000
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 plus .90% due 2016
Liabilities
Long-term debt	125,000,000	0
HEI medium-term note 6.51%, due 2014
Liabilities
Long-term debt	$ 0	$ 100,000,000
Shareholders' equity
Interest rate of medium-term notes (as a percent)	6.51%	6.51%
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%
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%
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%
Hawaiian Electric Industries, Inc.
ASSETS
Cash and cash equivalents	$ 276,000	$ 571,000		$ 18,021,000		$ 1,765,000
Accounts receivable	1,991,000	1,661,000
Property, plant and equipment, net	4,917,000	5,419,000
Deferred income tax assets	15,922,000	10,057,000
Other assets	11,070,000	9,550,000
Investments in subsidiaries, at equity	2,224,452,000	2,122,841,000
Total assets	2,258,628,000	2,150,099,000
Liabilities
Accounts payable	1,993,000	817,000
Interest payable	2,583,000	4,630,000
Notes payable to subsidiaries	7,857,000	7,936,000
Commercial paper	118,972,000	105,482,000
Long-term debt	300,000,000	275,000,000
Retirement benefits liability	32,030,000	21,559,000
Other	3,765,000	7,605,000
Total liabilities	467,200,000	423,029,000
Shareholders' equity
Preferred stock, no par value, authorized 10,000,000 shares; issued: none	0	0
Common stock, no par value, authorized 200,000,000 shares; issued and outstanding: 102,565,266 shares and 101,259,800 shares at December 31, 2014 and 2013, respectively	1,521,297,000	1,488,126,000
Retained earnings	297,509,000	255,694,000
Accumulated other comprehensive loss	(27,378,000)	(16,750,000)
Total shareholders' equity	1,791,428,000	1,727,070,000
Total liabilities and shareholders' equity	2,258,628,000	$ 2,150,099,000
Aggregate principal payments
2015	0
2016	200,000,000
2017	0
2018	0
2019	$ 0
Preferred stock, authorized shares	10,000,000	10,000,000
Common stock, authorized shares	200,000,000	200,000,000
Common stock, issued shares	102,565,266	101,259,800
Common stock, outstanding shares	102,565,266	101,259,800
Deferred income taxes		$ 0
Hawaiian Electric Industries, Inc. | HEI term loan LIBOR plus .90% due 2016
Liabilities
Long-term debt	$ 125,000,000	0
Hawaiian Electric Industries, Inc. | HEI medium-term note 6.51%, due 2014
Liabilities
Long-term debt	$ 0	$ 100,000,000
Shareholders' equity
Interest rate of medium-term notes (as a percent)	6.51%	6.51%
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%
As previously filed | Hawaiian Electric Industries, Inc.
ASSETS
Deferred income tax assets		$ 1,594,000
Other assets		23,679,000
Total assets		2,155,765,000
Liabilities
Other		1,886,000
Total liabilities		428,695,000
Shareholders' equity
Total liabilities and shareholders' equity		2,155,765,000
Aggregate principal payments
Deferred income taxes		11,385,000
Difference
ASSETS
Other assets		(7,000,000)
Difference | Hawaiian Electric Industries, Inc.
ASSETS
Deferred income tax assets		8,463,000
Other assets		(14,129,000)
Total assets		(5,666,000)
Liabilities
Other		5,719,000
Total liabilities		(5,666,000)
Shareholders' equity
Total liabilities and shareholders' equity		(5,666,000)
Aggregate principal payments
Deferred income taxes		$ (11,385,000)
LIBOR | HEI term loan LIBOR plus .90% due 2016
Aggregate principal payments
Line of credit facility basis point spread (as a percent)	0.90%

[1] As restated - See Note 1, “Summary of significant accounting policies - Revision and restatements of previously issued financial statements.”