Consolidated Statements of Capitalization - HECO - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020
Common stock equity
Retained earnings	$ 757,921	$ 660,398
Accumulated other comprehensive loss, net of tax benefits-retirement benefit plans	(16,858)	(17,887)
Total shareholders’ equity	2,390,884	2,337,502
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, 2021 and 2020, respectively	118,376	115,515
Premium on capital stock	798,526	746,987
Retained earnings	1,348,277	1,282,335
Accumulated other comprehensive loss, net of tax benefits-retirement benefit plans	(3,280)	(2,919)
Total shareholders’ equity	$ 2,261,899	$ 2,141,918
Shares outstanding (in shares)	1,234,657	1,234,657
Cumulative preferred stock – not subject to mandatory redemption	$ 34,293	$ 34,293
Long-term debt	1,684,000	1,569,000
Less unamortized debt issuance costs	7,598	7,698
Less current portion long-term debt, net of unamortized debt issuance costs	51,975	0
Long-term debt, net	1,624,427	1,561,302
Total capitalization	3,920,619	3,737,513
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
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
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
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
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
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes
Common stock equity
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
Common stock equity
Long-term debt	50,000	50,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 3.31%, Series 2020A and 2020B, due 2030
Common stock equity
Long-term debt	110,000	110,000
Hawaiian Electric Company, Inc. and Subsidiaries | Senior notes | 4.21%, Series 2019A, due 2034
Common stock equity
Long-term debt	50,000	50,000
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 | 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 | 4.55%, 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 | Preferred Stock $20 Par Value
Common stock equity
Par Value (in dollars per share)	$ 20	$ 20
Hawaiian Electric Company, Inc. and Subsidiaries | Preferred Stock $100 Par Value
Common stock equity
Par Value (in dollars per share)	100	100
Hawaiian Electric | Series C, 4.25% Preferred Stock
Common stock equity
Par Value (in dollars per share)	$ 20	$ 20
Shares outstanding (in shares)	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
Par Value (in dollars per share)	$ 20	$ 20
Shares outstanding (in shares)	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
Par Value (in dollars per share)	$ 20	$ 20
Shares outstanding (in shares)	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
Par Value (in dollars per share)	$ 20	$ 20
Shares outstanding (in shares)	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
Par Value (in dollars per share)	$ 20	$ 20
Shares outstanding (in shares)	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
Par Value (in dollars per share)	$ 20	$ 20
Shares outstanding (in shares)	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
Par Value (in dollars per share)	$ 20	$ 20
Shares outstanding (in shares)	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
Par Value (in dollars per share)	$ 100	$ 100
Shares outstanding (in shares)	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
Par Value (in dollars per share)	$ 100	$ 100
Shares outstanding (in shares)	50,000	50,000
Cumulative preferred stock – not subject to mandatory redemption	$ 5,000	$ 5,000