Consolidated Statements of Capitalization - HECO - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019
Common stock equity
Retained earnings	$ 660,398	$ 622,042
Accumulated other comprehensive loss, net of tax benefits-retirement benefit plans	(17,887)	(20,907)
Total shareholders’ equity	2,337,502	2,280,260
Hawaiian Electric Company, Inc. and Subsidiaries
Common stock equity
Common stock of $6 2/3 par value, Authorized: 50,000,000 shares. Outstanding: shares and 17,048,783 shares at December 31, 2020 and 2019, respectively	115,515	113,678
Premium on capital stock	746,987	714,824
Retained earnings	1,282,335	1,220,129
Accumulated other comprehensive loss, net of tax benefits-retirement benefit plans	(2,919)	(1,279)
Total shareholders’ equity	$ 2,141,918	$ 2,047,352
Shares outstanding December 31, 2020 and 2019	1,234,657	1,234,657
Cumulative preferred stock – not subject to mandatory redemption	$ 34,293	$ 34,293
Long-term debt	1,569,000	1,505,000
Less unamortized debt issuance costs	7,698	7,333
Less current portion long-term debt, net of unamortized debt issuance costs	0	95,953
Long-term debt, net	1,561,302	1,401,714
Total capitalization	3,737,513	3,483,359
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds
Common stock equity
Long-term debt	542,000	542,000
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds | 3.50%, Series 2019, due 2049
Common stock equity
Long-term debt	$ 80,000	80,000
Debt instrument, stated interest rate	3.50%
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds | 3.20%, Refunding series 2019, due 2039
Common stock equity
Long-term debt	$ 150,000	150,000
Debt instrument, stated interest rate	3.20%
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds | 3.10%, Refunding series 2017A, due 2026
Common stock equity
Long-term debt	$ 125,000	125,000
Debt instrument, stated interest rate	3.10%
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds | 4.00%, Refunding series 2017B, due 2037
Common stock equity
Long-term debt	$ 140,000	140,000
Debt instrument, stated interest rate	4.00%
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds | 3.25%, Refunding series 2015, due 2025
Common stock equity
Long-term debt	$ 47,000	47,000
Debt instrument, stated interest rate	3.25%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes
Common stock equity
Long-term debt	$ 1,027,000	963,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 3.96%, Series 2020A, 2020B and 2020C, due 2050
Common stock equity
Long-term debt	$ 50,000	0
Debt instrument, stated interest rate	3.96%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 3.31%, Series 2020A and 2020B, due 2030
Common stock equity
Long-term debt	$ 110,000	0
Debt instrument, stated interest rate	3.31%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.21%, Series 2019A, due 2034
Common stock equity
Long-term debt	$ 50,000	50,000
Debt instrument, stated interest rate	4.21%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.38%, Series 2018A, due 2028
Common stock equity
Long-term debt	$ 67,500	67,500
Debt instrument, stated interest rate	4.38%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.53%, Series 2018B, due 2033
Common stock equity
Long-term debt	$ 17,500	17,500
Debt instrument, stated interest rate	4.53%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.72%, Series 2018C, due 2048
Common stock equity
Long-term debt	$ 15,000	15,000
Debt instrument, stated interest rate	4.72%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.31%, Series 2017A, due 2047
Common stock equity
Long-term debt	$ 50,000	50,000
Debt instrument, stated interest rate	4.31%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.54%, Series 2016A, due 2046
Common stock equity
Long-term debt	$ 40,000	40,000
Debt instrument, stated interest rate	4.54%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 5.23%, Series 2015A, due 2045
Common stock equity
Long-term debt	$ 80,000	80,000
Debt instrument, stated interest rate	5.23%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 3.83%, Series 2013A, due 2020 - paid in 2020
Common stock equity
Long-term debt	$ 0	14,000
Debt instrument, stated interest rate	3.83%
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
Debt instrument, stated interest rate	4.45%
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
Debt instrument, stated interest rate	4.84%
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
Debt instrument, stated interest rate	5.65%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.03%, Series 2012B, due 2020 - paid in 2020
Common stock equity
Long-term debt	$ 0	82,000
Debt instrument, stated interest rate	4.03%
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
Debt instrument, stated interest rate	4.55%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.72%, Series 2012D, due 2029
Common stock equity
Long-term debt	$ 35,000	35,000
Debt instrument, stated interest rate	4.72%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 5.39%, Series 2012E, due 2042
Common stock equity
Long-term debt	$ 150,000	150,000
Debt instrument, stated interest rate	5.39%
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.53%, Series 2012F, due 2032
Common stock equity
Long-term debt	$ 40,000	$ 40,000
Debt instrument, stated interest rate	4.53%
Hawaiian Electric Company, Inc. and Subsidiaries | Preferred Stock $20 Par Value
Common stock equity
Preferred stock, par value (in dollars per share)	$ 20	$ 20
Hawaiian Electric Company, Inc. and Subsidiaries | Preferred Stock $100 Par Value
Common stock equity
Preferred stock, par value (in dollars per share)	100	$ 100
Hawaiian Electric | Series C, 4.25% Preferred Stock
Common stock equity
Preferred stock, par value (in dollars per share)	$ 20
Shares outstanding December 31, 2020 and 2019	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, 2020 and 2019	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, 2020 and 2019	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, 2020 and 2019	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, 2020 and 2019	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, 2020 and 2019	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, 2020 and 2019	175,000	175,000
Cumulative preferred stock – not subject to mandatory redemption	$ 3,500	$ 3,500
HELCO | Series G, 7.625% Preferred Stock
Common stock equity
Preferred stock, par value (in dollars per share)	$ 100
Shares outstanding December 31, 2020 and 2019	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, 2020 and 2019	50,000	50,000
Cumulative preferred stock – not subject to mandatory redemption	$ 5,000	$ 5,000