Consolidated Statements of Capitalization - HECO - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Common stock equity
Retained earnings	$ 622,042	$ 543,623
Accumulated other comprehensive income (loss), net of taxes-retirement benefit plans	(20,907)	(25,751)
Total shareholders’ equity	2,280,260	2,162,280
Hawaiian Electric Company, Inc. and Subsidiaries
Common stock equity
Common stock of $6 2/3 par value, Authorized: 50,000,000 shares. Outstanding: 16,142,216 shares and 16,019,785 shares at December 31, 2017 and 2016, respectively	113,678	111,696
Premium on capital stock	714,824	681,305
Retained earnings	1,220,129	1,164,541
Accumulated other comprehensive income (loss), net of taxes-retirement benefit plans	(1,279)	99
Total shareholders’ equity	$ 2,047,352	1,957,641
Shares outstanding December 31, 2019 and 2018	1,234,657
Cumulative preferred stock – not subject to mandatory redemption	$ 34,293	34,293
Long-term debt	1,505,000	1,426,546
Less unamortized debt issuance costs	7,333	7,744
Less current portion long-term debt, net of unamortized debt issuance costs	95,953	0
Long-term debt, net	1,401,714	1,418,802
Total capitalization	3,483,359	3,410,736
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds
Common stock equity
Long-term debt	542,000	462,000
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds | 3.50%, Series 2019, due 2049
Common stock equity
Long-term debt		0
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds | 3.20%, Refunding series 2019, due 2039
Common stock equity
Long-term debt		0
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds | 6.50%, Series 2009, due 2039 - redeemed in 2019
Common stock equity
Long-term debt	0
Hawaiian Electric Company, Inc. and Subsidiaries | Unsecured Debt
Common stock equity
Long-term debt	963,000	964,546
Hawaiian Electric Company, Inc. and Subsidiaries | Unsecured Debt | 3.50%, Series 2019, due 2049
Common stock equity
Long-term debt	80,000
Hawaiian Electric Company, Inc. and Subsidiaries | Unsecured Debt | 3.20%, Refunding series 2019, due 2039
Common stock equity
Long-term debt	150,000
Hawaiian Electric Company, Inc. and Subsidiaries | Unsecured Debt | 3.10%, Refunding series 2017A, due 2026
Common stock equity
Long-term debt	125,000	125,000
Hawaiian Electric Company, Inc. and Subsidiaries | Unsecured Debt | 4.00%, Refunding series 2017B, due 2037
Common stock equity
Long-term debt	140,000	140,000
Hawaiian Electric Company, Inc. and Subsidiaries | Unsecured Debt | 3.25%, Refunding series 2015, due 2025
Common stock equity
Long-term debt	47,000	47,000
Hawaiian Electric Company, Inc. and Subsidiaries | Unsecured Debt | 6.50%, Series 2009, due 2039 - redeemed in 2019
Common stock equity
Long-term debt		150,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes
Common stock equity
Long-term debt	963,000	913,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.21%, Series 2019A, due 2033
Common stock equity
Long-term debt	50,000	0
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.38%, Series 2018A, due 2028
Common stock equity
Long-term debt	67,500	67,500
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.53%, Series 2018B, due 2033
Common stock equity
Long-term debt	17,500	17,500
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.72%, Series 2018C, due 2048
Common stock equity
Long-term debt	15,000	15,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.31%, Series 2017A, due 2047
Common stock equity
Long-term debt	50,000	50,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.54%, Series 2016A, due 2046
Common stock equity
Long-term debt	40,000	40,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 5.23%, Series 2015A, due 2045
Common stock equity
Long-term debt	80,000	80,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 3.83%, Series 2013A, due 2020
Common stock equity
Long-term debt	14,000	14,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.45%, Series 2013A and 2013B, due 2022
Common stock equity
Long-term debt	52,000	52,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.84%, Series 2013A, 2013B and 2013C, due 2027
Common stock equity
Long-term debt	100,000	100,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 5.65%, Series 2013B and 2013C, due 2043
Common stock equity
Long-term debt	70,000	70,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.03%, Series 2012B, due 2020
Common stock equity
Long-term debt	82,000	82,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.55%, Series 2012B and 2012C, due 2023
Common stock equity
Long-term debt	100,000	100,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.72%, Series 2012D, due 2029
Common stock equity
Long-term debt	35,000	35,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 5.39%, Series 2012E, due 2042
Common stock equity
Long-term debt	150,000	150,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.53%, Series 2012F, due 2032
Common stock equity
Long-term debt	40,000	40,000
Hawaiian Electric Company, Inc. and Subsidiaries | Junior subordinated debt | 6.50 %, series 2004, Junior subordinated deferrable interest debentures, due 2034 - redeemed in 2019
Common stock equity
Long-term debt	$ 0	$ 51,546
Hawaiian Electric | Series C, 4.25% Preferred Stock
Common stock equity
Preferred stock, par value (in dollars per share)	$ 20
Shares outstanding December 31, 2019 and 2018	150,000	150,000
Cumulative preferred stock – not subject to mandatory redemption	$ 3,000	$ 3,000
Hawaiian Electric | Series D, 5.00% Preferred Stock
Common stock equity
Preferred stock, par value (in dollars per share)	$ 20
Shares outstanding December 31, 2019 and 2018	50,000	50,000
Cumulative preferred stock – not subject to mandatory redemption	$ 1,000	$ 1,000
Hawaiian Electric | Series E, 5.00% Preferred Stock
Common stock equity
Preferred stock, par value (in dollars per share)	$ 20
Shares outstanding December 31, 2019 and 2018	150,000	150,000
Cumulative preferred stock – not subject to mandatory redemption	$ 3,000	$ 3,000
Hawaiian Electric | Series H, 5.25% Preferred Stock
Common stock equity
Preferred stock, par value (in dollars per share)	$ 20
Shares outstanding December 31, 2019 and 2018	250,000	250,000
Cumulative preferred stock – not subject to mandatory redemption	$ 5,000	$ 5,000
Hawaiian Electric | Series I, 5.00% Preferred Stock
Common stock equity
Preferred stock, par value (in dollars per share)	$ 20
Shares outstanding December 31, 2019 and 2018	89,657	89,657
Cumulative preferred stock – not subject to mandatory redemption	$ 1,793	$ 1,793
Hawaiian Electric | Series J, 4.75% Preferred Stock
Common stock equity
Preferred stock, par value (in dollars per share)	$ 20
Shares outstanding December 31, 2019 and 2018	250,000	250,000
Cumulative preferred stock – not subject to mandatory redemption	$ 5,000	$ 5,000
Hawaiian Electric | Series K, 4.65% Preferred Stock
Common stock equity
Preferred stock, par value (in dollars per share)	$ 20
Shares outstanding December 31, 2019 and 2018	175,000	175,000
Cumulative preferred stock – not subject to mandatory redemption	$ 3,500	$ 3,500
Hawaii Electric Light | Series G, 7.625% Preferred Stock
Common stock equity
Preferred stock, par value (in dollars per share)	$ 100
Shares outstanding December 31, 2019 and 2018	70,000	70,000
Cumulative preferred stock – not subject to mandatory redemption	$ 7,000	$ 7,000
Maui Electric | Series H, 7.625% Preferred Stock
Common stock equity
Preferred stock, par value (in dollars per share)	$ 100
Shares outstanding December 31, 2019 and 2018	50,000	50,000
Cumulative preferred stock – not subject to mandatory redemption	$ 5,000	$ 5,000