Variable Interest Entities	12 Months Ended
Dec. 31, 2022
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	NOTE 6. VARIABLE INTEREST ENTITIES Lancaster Power Purchase Agreement The Company has a PPA for the purchase of all the output of the Lancaster Plant, a 270 MW natural gas-fired combined cycle combustion turbine plant located in Kootenai County, Idaho, owned by an unrelated third-party (Rathdrum Power LLC(Rathdrum)), through 2026. Avista Corp. has a variable interest in Rathdrum through the PPA. Accordingly, Avista Corp. made an evaluation of which interest holders have the power to direct the activities that most significantly impact the economic performance of Rathdrum and which interest holders have the obligation to absorb losses or receive benefits that could be significant to Rathdrum. Avista Corp. pays a fixed capacity and operations and maintenance payment and certain monthly variable costs under the PPA. Under the terms of the PPA, Avista Corp. makes the dispatch decisions, provides all natural gas fuel and receives all of the electric energy output from the plant. However, Rathdrum as the owner of the plant controls the daily operation of the plant and makes operating and maintenance decisions, both during the term of the PPA and after its expiration in 2026. Also, Rathdrum controls the rights and obligations with respect to the plant after the PPA expiration and Avista Corp. will not have further obligations with respect to the plant. It is estimated that the plant will have 15 to 25 years of useful life after that time. Rathdrum bears the maintenance risk of the plant and will receive the residual value of the plant. Avista Corp. has no debt or equity investments in the Lancaster Plant and does not provide financial support through liquidity arrangements or other commitments (other than the PPA). Based on its analysis, Avista Corp. does not consider itself to be the primary beneficiary of Rathdrum or the plant. Accordingly, neither the Lancaster Plant nor Rathdrum is included in Avista Corp.’s consolidated financial statements. The Company has a future contractual obligation of $117.4 million under the PPA (representing the fixed capacity and operations and maintenance payments through 2026) and believes this would be its maximum exposure to loss. The Company believes that such costs will be recovered through retail rates. Limited Partnerships and Similar Entities Under GAAP, a limited partnership or similar legal entity that is the functional equivalent of a limited partnership is considered a VIE regardless of whether it otherwise qualifies as a voting interest entity unless a simple majority or lower threshold of the “unrelated” limited partners (i.e., parties other than the general partner, entities under common control with the general partner, and other parties acting on behalf of the general partner) have substantive kick-out rights (including liquidation rights) or participating rights. The Company has investments in limited partnerships (or the functional equivalent) where Avista Corp. is a limited partner investor in an investment fund where the general partner makes all of the investment and operating decisions with regards to the partnership and fund. To remove the general partner from any of the funds, approval from greater than a simple majority of the limited partners is required. As such, the limited partners do not have substantive kick-out rights and these investments are considered VIEs. Consolidation of these VIEs by Avista Corp. is not required because the Company does not have majority ownership in any of the funds, it does not have the power to direct any activities of the funds, and it does not have the power to appoint executive leadership, including the board of directors. Avista Corp. participates in profits and losses of the investment funds based on its ownership percentage and its losses are capped at its total initial investment in the funds. Equity investments in VIEs are accounted for under the equity method (see Note 7). As of December 31, 2022, Avista Corp. has invested $63.4 million in these investment funds, with an additional commitment of $25.6 million remaining to be invested. The Company is not allowed to withdraw any capital contributions from any investment fund until after that fund expiration date and all liabilities of that fund are settled. The expiration dates range from 2025 to 2036, with some investments having no termination date (as they are perpetual). As of December 31, 2022, the Company has a total carrying amount of $79.8 million in these VIEs, including $70.2 million of equity investments and $9.6 million of notes receivable.

Variable Interest Entities

12 Months Ended

Dec. 31, 2022

Organization, Consolidation and Presentation of Financial Statements [Abstract]

NOTE 6. VARIABLE INTEREST ENTITIES

Lancaster Power Purchase Agreement

The Company has a PPA for the purchase of all the output of the Lancaster Plant, a 270 MW natural gas-fired combined cycle combustion turbine plant located in Kootenai County, Idaho, owned by an unrelated third-party (Rathdrum Power LLC(Rathdrum)), through 2026.

Avista Corp. has a variable interest in Rathdrum through the PPA. Accordingly, Avista Corp. made an evaluation of which interest holders have the power to direct the activities that most significantly impact the economic performance of Rathdrum and which interest holders have the obligation to absorb losses or receive benefits that could be significant to Rathdrum. Avista Corp. pays a fixed capacity and operations and maintenance payment and certain monthly variable costs under the PPA. Under the terms of the PPA, Avista Corp. makes the dispatch decisions, provides all natural gas fuel and receives all of the electric energy output from the plant. However, Rathdrum as the owner of the plant controls the daily operation of the plant and makes operating and maintenance decisions, both during the term of the PPA and after its expiration in 2026. Also, Rathdrum controls the rights and obligations with respect to the plant after the PPA expiration and Avista Corp. will not have further obligations with respect to the plant. It is estimated that the plant will have 15 to 25 years of useful life after that time. Rathdrum bears the maintenance risk of the plant and will receive the residual value of the plant. Avista Corp. has no debt or equity investments in the Lancaster Plant and does not provide financial support through liquidity arrangements or other commitments (other than the PPA). Based on its analysis, Avista Corp. does not consider itself to be the primary beneficiary of Rathdrum or the plant. Accordingly, neither the Lancaster Plant nor Rathdrum is included in Avista Corp.’s consolidated financial statements. The Company has a future contractual obligation of $117.4 million under the PPA (representing the fixed capacity and operations and maintenance payments through 2026) and believes this would be its maximum exposure to loss. The Company believes that such costs will be recovered through retail rates.

Limited Partnerships and Similar Entities

Under GAAP, a limited partnership or similar legal entity that is the functional equivalent of a limited partnership is considered a VIE regardless of whether it otherwise qualifies as a voting interest entity unless a simple majority or lower threshold of the “unrelated” limited partners (i.e., parties other than the general partner, entities under common control with the general partner, and other parties acting on behalf of the general partner) have substantive kick-out rights (including liquidation rights) or participating rights.

The Company has investments in limited partnerships (or the functional equivalent) where Avista Corp. is a limited partner investor in an investment fund where the general partner makes all of the investment and operating decisions with regards to the partnership and fund. To remove the general partner from any of the funds, approval from greater than a simple majority of the limited partners is required. As such, the limited partners do not have substantive kick-out rights and these investments are considered VIEs. Consolidation of these VIEs by Avista Corp. is not required because the Company does not have majority ownership in any of the funds, it does not have the power to direct any activities of the funds, and it does not have the power to appoint executive leadership, including the board of directors.

Avista Corp. participates in profits and losses of the investment funds based on its ownership percentage and its losses are capped at its total initial investment in the funds. Equity investments in VIEs are accounted for under the equity method (see Note 7). As of December 31, 2022, Avista Corp. has invested $63.4 million in these investment funds, with an additional commitment of $25.6 million remaining to be invested. The Company is not allowed to withdraw any capital contributions from any investment fund until after that fund expiration date and all liabilities of that fund are settled. The expiration dates range from 2025 to 2036, with some investments having no termination date (as they are perpetual). As of December 31, 2022, the Company has a total carrying amount of $79.8 million in these VIEs, including $70.2 million of equity investments and $9.6 million of notes receivable.