Short-Term Borrowings - Additional Information (Details) - USD ($) |
6 Months Ended | |
|---|---|---|
Jun. 30, 2026 |
Dec. 31, 2025 |
|
| Avista Utilities [Member] | ||
| Short-term Debt [Line Items] | ||
| Line of credit facility, maximum borrowing capacity | $ 500,000,000 | |
| Line of credit facility, expiration date | 2029-06 | |
| Line of credit facility, covenant terms, maximum debt to equity ratio | 65.00% | |
| Letters of credit outstanding | $ 5,000,000 | $ 5,000,000 |
| Avista Utilities [Member] | Letter of Credit [Member] | ||
| Short-term Debt [Line Items] | ||
| Principal amount | 65,000,000 | 50,000,000 |
| Letters of credit outstanding | 6,000,000 | $ 14,000,000 |
| Alaska Electric Light & Power [Member] | ||
| Short-term Debt [Line Items] | ||
| Line of credit facility, maximum borrowing capacity | $ 25,000,000 | |
| Line of credit facility, expiration date | 2028-06 | |
| Line of credit, outstanding | $ 0 | |
| Line of credit facility, covenant terms, maximum debt to equity ratio | 67.50% |
| X | ||||||||||
- Definition Line of credit facility expiration date. No definition available.
|
| X | ||||||||||
- Definition Line of Credit Facility, Covenant Terms, Maximum Debt to Equity Ratio No definition available.
|
| X | ||||||||||
- Definition Face (par) amount of debt instrument at time of issuance. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. Reference 1: http://www.xbrl.org/2003/role/exampleRef
|
| X | ||||||||||
- Definition Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition The carrying value as of the balance sheet date of the current portion of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement. Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
|
| X | ||||||||||
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. Reference 1: http://www.xbrl.org/2003/role/disclosureRef
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|
| X | ||||||||||
- Details
|