XML 146 R111.htm IDEA: XBRL DOCUMENT v3.22.0.1
Committed Lines of Credit - Additional Information (Details) - USD ($)
1 Months Ended 12 Months Ended
Jun. 30, 2021
Dec. 31, 2021
Dec. 31, 2020
Apr. 30, 2014
Avista Utilities [Member]        
Short-term Debt [Line Items]        
Line of credit facility, maximum borrowing capacity       $ 400,000,000.0
Line of credit facility, expiration date 2026-06      
Line of credit facility additional expiration period   1 year    
Line of credit facility, covenant terms, maximum debt to equity ratio   65.00%    
Average interest rate   1.11% 1.22%  
Alaska Electric Light & Power [Member]        
Short-term Debt [Line Items]        
Line of credit facility, maximum borrowing capacity   $ 25,000,000.0    
Line of credit facility, expiration date   2024-11    
Line of credit facility, covenant terms, maximum debt to equity ratio   67.50%    
Line of credit, outstanding   $ 0 $ 1,000,000.0  
Average interest rate     1.65%