Long-Term Debt - Schedule Of Long-Term Debt Maturities (Details) - Future Long Term Debt Maturities Including Long Term Debt To Affiliated Trusts [Member] $ in Millions	Dec. 31, 2025 USD ($)
Debt Instrument [Line Items]
2028	$ 25
2029	15
2030	20
Thereafter	2,766
Total	$ 2,826

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.

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+ Details

- Definition

Amount, after deduction of unamortized premium (discount) and debt issuance cost, of long-term debt. Excludes lease obligation.

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+ Details

AVISTA CORP 10-K