Unconsolidated variable interest entities (Details)	1 Months Ended						12 Months Ended
	Nov. 30, 2015 MW	Oct. 31, 2015 MW	Oct. 31, 2004 MW	Mar. 31, 2004 USD ($) security	Oct. 31, 1988 MW	Mar. 31, 1988 MW	Dec. 31, 2016 USD ($) agreement entity	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Power purchase agreement
Number of power purchase agreements (PPAs) | agreement							5
Accounts payable							$ 143,279,000	$ 138,523,000
HECO
Power purchase agreement
Number of power purchase agreements (PPAs) | agreement							5
Percentage of power purchase from AES Hawaii, Inc. (AES Hawaii), Kalaeloa Partners, L.P. (Kalaeloa), Hamakua Energy Partners, L.P. (HEP) and HPOWER							90.00%
Purchases from IPPs							$ 431,009,000	440,983,000	$ 537,821,000
Number of entities owning wind farms not required to be consolidated as VIE's | entity							2
Minimum potential number of IPP entities consolidated into company in the future | entity							1
HECO | AES Hawaii, Inc. (AES Hawaii)
Power purchase agreement
Power purchase capacity (in megawatts) | MW	189					180
Number of years entity entered under power purchase agreement						30 years
Accounts payable							$ 13,000,000
HECO | Kalaeloa Partners, L.P. (Kalaeloa)
Power purchase agreement
Power purchase capacity (in megawatts) | MW					180
Number of years entity entered under power purchase agreement					25 years
Power purchase capacity that Increases from initial capacity (in megawatts) | MW			208
Power purchase agreement, termination period			60 days
Accounts payable							12,000,000
Hawaii Electric Light Company, Inc. (HELCO)
Power purchase agreement
Purchases from IPPs							81,018,000	97,503,000	123,226,000
Hawaiian Electric Company, Inc. and Subsidiaries
Power purchase agreement
Purchases from IPPs							562,740,000	594,096,000	722,008,000
Hawaiian Electric Company, Inc. and Subsidiaries | AES Hawaii, Inc. (AES Hawaii)
Power purchase agreement
Purchases from IPPs							149,000,000	134,000,000	145,000,000
Hawaiian Electric Company, Inc. and Subsidiaries | Kalaeloa Partners, L.P. (Kalaeloa)
Power purchase agreement
Purchases from IPPs							152,000,000	187,000,000	279,000,000
Hawaiian Electric Company, Inc. and Subsidiaries | Hamakua Energy Partners, L.P. (HEP)
Power purchase agreement
Purchases from IPPs							29,000,000	44,000,000	51,000,000
Hawaiian Electric Company, Inc. and Subsidiaries | HPOWER
Power purchase agreement
Purchases from IPPs							71,000,000	66,000,000	66,000,000
Hawaiian Electric Company, Inc. and Subsidiaries | Puna Geothermal Venture
Power purchase agreement
Purchases from IPPs							28,000,000	29,000,000	45,000,000
Hawaiian Electric Company, Inc. and Subsidiaries | Hawaiian Commercial & Sugar (HC&S)
Power purchase agreement
Purchases from IPPs							1,000,000	8,000,000	15,000,000
Hawaiian Electric Company, Inc. and Subsidiaries | Other IPPs
Power purchase agreement
Purchases from IPPs							133,000,000	126,000,000	121,000,000
Maui Electric Company, Limited (MECO)
Power purchase agreement
Purchases from IPPs							$ 50,713,000	$ 55,610,000	$ 60,961,000
Maximum monthly scheduled energy (in megawatts) | MW		4
Maximum emergency power (in megawatts) | MW		16
HECO Capital Trust III
Unconsolidated variable interest entities
Variable interest entity, ownership percentage							100.00%
Investment in 2004 Debentures							$ 51,500,000
Interest income							3,400,000
HECO Capital Trust III | HECO
Unconsolidated variable interest entities
Principal amount of 2004 Debentures				$ 31,500,000
HECO Capital Trust III | HECO | 2004 Trust Preferred Securities
Unconsolidated variable interest entities
Number of 2004 Trust Preferred Securities issued | security				2,000,000
Dividend rate on 2004 Trust Preferred Securities (as a percent)				6.50%
Aggregate Liquidation preference				$ 50,000,000
Balance of Trust Securities							50,000,000
Dividend distributions on Trust Preferred Securities							3,300,000
HECO Capital Trust III | HECO | Trust Common Securities
Unconsolidated variable interest entities
Aggregate Liquidation preference				1,500,000
Balance of Trust Securities							1,500,000
Common dividend							$ 100,000
HECO Capital Trust III | Hawaii Electric Light Company, Inc. (HELCO)
Unconsolidated variable interest entities
Principal amount of 2004 Debentures				10,000,000
HECO Capital Trust III | Maui Electric Company, Limited (MECO)
Unconsolidated variable interest entities
Principal amount of 2004 Debentures				$ 10,000,000