Consolidated Statements of Capitalization - HECO (Parenthetical) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Common stock, authorized shares (in shares)	200,000,000	200,000,000
Common stock, outstanding shares (in shares)	109,311,785	109,181,124
Hawaiian Electric Company, Inc. and Subsidiaries
Common stock, par value (in dollars per share)	$ 6.667	$ 6.667
Common stock, authorized shares (in shares)	50,000,000	50,000,000
Common stock, outstanding shares (in shares)	17,753,533	17,324,376
Long-term debt	$ 1,684,000	$ 1,569,000
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds
Long-term debt	$ 542,000	542,000
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds | 3.50%, Series 2019, due 2049
Debt instrument, stated interest rate	3.50%
Long-term debt	$ 80,000	80,000
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds | 3.20%, Refunding series 2019, due 2039
Debt instrument, stated interest rate	3.20%
Long-term debt	$ 150,000	150,000
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds | 3.10%, Refunding series 2017A, due 2026
Debt instrument, stated interest rate	3.10%
Long-term debt	$ 125,000	125,000
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds | 4.00%, Refunding series 2017B, due 2037
Debt instrument, stated interest rate	4.00%
Long-term debt	$ 140,000	140,000
Hawaiian Electric Company, Inc. and Subsidiaries | Special Purpose Revenue Bonds | 3.25%, Refunding series 2015, due 2025
Debt instrument, stated interest rate	3.25%
Long-term debt	$ 47,000	47,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes
Long-term debt	$ 1,142,000	1,027,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 3.96%, Series 2020A, 2020B and 2020C, due 2050
Debt instrument, stated interest rate	3.96%
Long-term debt	$ 50,000	50,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 3.51%, Series 2020C and 2020E, due 2050
Debt instrument, stated interest rate	3.51%
Long-term debt	$ 70,000	0
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 3.28%, Series 2020B and 2020D, due 2040
Debt instrument, stated interest rate	3.28%
Long-term debt	$ 45,000	0
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 3.31%, Series 2020A and 2020B, due 2030
Debt instrument, stated interest rate	3.31%
Long-term debt	$ 110,000	110,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.21%, Series 2019A, due 2034
Debt instrument, stated interest rate	4.21%
Long-term debt	$ 50,000	50,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.38%, Series 2018A, due 2028
Debt instrument, stated interest rate	4.38%
Long-term debt	$ 67,500	67,500
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.53%, Series 2018B, due 2033
Debt instrument, stated interest rate	4.53%
Long-term debt	$ 17,500	17,500
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.72%, Series 2018C, due 2048
Debt instrument, stated interest rate	4.72%
Long-term debt	$ 15,000	15,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.31%, Series 2017A, due 2047
Debt instrument, stated interest rate	4.31%
Long-term debt	$ 50,000	50,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.54%, Series 2016A, due 2046
Debt instrument, stated interest rate	4.54%
Long-term debt	$ 40,000	40,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 5.23%, Series 2015A, due 2045
Debt instrument, stated interest rate	5.23%
Long-term debt	$ 80,000	80,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.45%, Series 2013A and 2013B, due 2022
Debt instrument, stated interest rate	4.45%
Long-term debt	$ 52,000	52,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.84%, Series 2013A, 2013B and 2013C, due 2027
Debt instrument, stated interest rate	4.84%
Long-term debt	$ 100,000	100,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 5.65%, Series 2013B and 2013C, due 2043
Debt instrument, stated interest rate	5.65%
Long-term debt	$ 70,000	70,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.55%, Series 2012B and 2012C, due 2023
Debt instrument, stated interest rate	4.55%
Long-term debt	$ 100,000	100,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.72%, Series 2012D, due 2029
Debt instrument, stated interest rate	4.72%
Long-term debt	$ 35,000	35,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 5.39%, Series 2012E, due 2042
Debt instrument, stated interest rate	5.39%
Long-term debt	$ 150,000	150,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.53%, Series 2012F, due 2032
Debt instrument, stated interest rate	4.53%
Long-term debt	$ 40,000	$ 40,000
Hawaiian Electric Company, Inc. and Subsidiaries | Preferred Stock $20 Par Value
Preferred stock, authorized shares (in shares)	5,000,000	5,000,000
Preferred stock, par value (in dollars per share)	$ 20	$ 20
Hawaiian Electric Company, Inc. and Subsidiaries | Preferred Stock $100 Par Value
Preferred stock, authorized shares (in shares)	7,000,000	7,000,000
Preferred stock, par value (in dollars per share)	$ 100	$ 100
Hawaiian Electric | Series C, 4.25% Preferred Stock
Preferred stock, par value (in dollars per share)	$ 20	$ 20
Preferred stock, stated dividend rate	4.25%	4.25%
Hawaiian Electric | Series D, 5.00% Preferred Stock
Preferred stock, par value (in dollars per share)	$ 20	$ 20
Preferred stock, stated dividend rate	5.00%	5.00%
Hawaiian Electric | Series E, 5.00% Preferred Stock
Preferred stock, par value (in dollars per share)	$ 20	$ 20
Preferred stock, stated dividend rate	5.00%	5.00%
Hawaiian Electric | Series H, 5.25% Preferred Stock
Preferred stock, par value (in dollars per share)	$ 20	$ 20
Preferred stock, stated dividend rate	5.25%	5.25%
Hawaiian Electric | Series I, 5.00% Preferred Stock
Preferred stock, par value (in dollars per share)	$ 20	$ 20
Preferred stock, stated dividend rate	5.00%	5.00%
Hawaiian Electric | Series J, 4.75% Preferred Stock
Preferred stock, par value (in dollars per share)	$ 20	$ 20
Preferred stock, stated dividend rate	4.75%	4.75%
Hawaiian Electric | Series K, 4.65% Preferred Stock
Preferred stock, par value (in dollars per share)	$ 20	$ 20
Preferred stock, stated dividend rate	4.65%	4.65%
Hawaii Electric Light | Series G, 7.625% Preferred Stock
Preferred stock, par value (in dollars per share)	$ 100	$ 100
Preferred stock, stated dividend rate	7.625%	7.625%
Maui Electric | Series H, 7.625% Preferred Stock
Preferred stock, par value (in dollars per share)	$ 100	$ 100
Preferred stock, stated dividend rate	7.625%	7.625%