XML 91 R57.htm IDEA: XBRL DOCUMENT v3.8.0.1
Electric utility segment - Regulatory Assets and Liabilities (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Regulatory assets    
Regulatory assets $ 869,297 $ 957,451
Regulatory liabilities    
Regulatory liabilities $ 880,770 410,693
Minimum | Income taxes    
Regulatory liabilities    
Authorized amortization or recovery periods 1 year  
Maximum | Income taxes    
Regulatory liabilities    
Authorized amortization or recovery periods 55 years  
Hawaiian Electric Company, Inc. and Subsidiaries    
Regulatory assets    
Regulatory assets $ 869,297 957,451
Regulatory liabilities    
Regulatory liabilities 880,770 410,693
Hawaiian Electric Company, Inc. and Subsidiaries | Cost of removal in excess of salvage value    
Regulatory liabilities    
Regulatory liabilities 453,986 394,072
Hawaiian Electric Company, Inc. and Subsidiaries | Income taxes    
Regulatory liabilities    
Regulatory liabilities 406,324 0
Hawaiian Electric Company, Inc. and Subsidiaries | Retirement benefit plans, regulatory liabilities    
Regulatory liabilities    
Regulatory liabilities $ 9,961 10,824
Authorized amortization or recovery periods 5 years  
Hawaiian Electric Company, Inc. and Subsidiaries | Other, regulatory liabilities    
Regulatory liabilities    
Regulatory liabilities $ 10,499 5,797
Authorized amortization or recovery periods 5 years  
Hawaiian Electric Company, Inc. and Subsidiaries | Minimum | Cost of removal in excess of salvage value    
Regulatory liabilities    
Authorized amortization or recovery periods 1 year  
Hawaiian Electric Company, Inc. and Subsidiaries | Minimum | Other, regulatory liabilities    
Regulatory liabilities    
Remaining amortization or recovery periods 1 year  
Hawaiian Electric Company, Inc. and Subsidiaries | Maximum | Cost of removal in excess of salvage value    
Regulatory liabilities    
Authorized amortization or recovery periods 60 years  
Hawaiian Electric Company, Inc. and Subsidiaries | Maximum | Other, regulatory liabilities    
Regulatory liabilities    
Remaining amortization or recovery periods 2 years  
Hawaiian Electric Company, Inc. and Subsidiaries | Current assets    
Regulatory assets    
Regulatory assets $ 88,390 66,032
Hawaiian Electric Company, Inc. and Subsidiaries | Long-term assets    
Regulatory assets    
Regulatory assets 780,907 891,419
Hawaiian Electric Company, Inc. and Subsidiaries | Current liabilities    
Regulatory liabilities    
Regulatory liabilities 3,401 3,762
Hawaiian Electric Company, Inc. and Subsidiaries | Long-term liabilities    
Regulatory liabilities    
Regulatory liabilities 877,369 406,931
Hawaiian Electric Company, Inc. and Subsidiaries | Retirement benefit plans, regulatory assets    
Regulatory assets    
Regulatory assets 637,204 745,367
Hawaiian Electric Company, Inc. and Subsidiaries | Income taxes    
Regulatory assets    
Regulatory assets $ 118,201 90,100
Hawaiian Electric Company, Inc. and Subsidiaries | Income taxes | Minimum    
Regulatory assets    
Authorized amortization or recovery periods 1 year  
Hawaiian Electric Company, Inc. and Subsidiaries | Income taxes | Maximum    
Regulatory assets    
Authorized amortization or recovery periods 55 years  
Hawaiian Electric Company, Inc. and Subsidiaries | Decoupling revenue balancing account    
Regulatory assets    
Regulatory assets $ 64,087 73,485
Hawaiian Electric Company, Inc. and Subsidiaries | Decoupling revenue balancing account | Minimum    
Regulatory assets    
Authorized amortization or recovery periods 1 year  
Hawaiian Electric Company, Inc. and Subsidiaries | Decoupling revenue balancing account | Maximum    
Regulatory assets    
Authorized amortization or recovery periods 2 years  
Hawaiian Electric Company, Inc. and Subsidiaries | Unamortized expense and premiums on retired debt and equity issuances    
Regulatory assets    
Regulatory assets $ 11,993 12,299
Hawaiian Electric Company, Inc. and Subsidiaries | Unamortized expense and premiums on retired debt and equity issuances | Minimum    
Regulatory assets    
Authorized amortization or recovery periods 19 years  
Remaining amortization or recovery periods 6 years  
Hawaiian Electric Company, Inc. and Subsidiaries | Unamortized expense and premiums on retired debt and equity issuances | Maximum    
Regulatory assets    
Authorized amortization or recovery periods 30 years  
Remaining amortization or recovery periods 18 years  
Hawaiian Electric Company, Inc. and Subsidiaries | Vacation earned, but not yet taken    
Regulatory assets    
Regulatory assets $ 11,224 10,970
Authorized amortization or recovery periods 1 year  
Hawaiian Electric Company, Inc. and Subsidiaries | Other, regulatory assets    
Regulatory assets    
Regulatory assets $ 26,588 $ 25,230
Hawaiian Electric Company, Inc. and Subsidiaries | Other, regulatory assets | Minimum    
Regulatory assets    
Authorized amortization or recovery periods 1 year  
Remaining amortization or recovery periods 1 year  
Hawaiian Electric Company, Inc. and Subsidiaries | Other, regulatory assets | Maximum    
Regulatory assets    
Authorized amortization or recovery periods 50 years  
Remaining amortization or recovery periods 46 years