Avista (AVA) 10-Q 2 Aug 23 2023 Q2 Quarterly report Financial data

Document and Entity Information

Document and Entity Information - shares	6 Months Ended
	Jun. 30, 2023	Jul. 28, 2023
Cover [Abstract]
Entity Registrant Name	AVISTA CORPORATION
Amendment Flag	false
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Information, Former Legal or Registered Name	None
City Area Code	509
Entity Incorporation, State or Country Code	WA
Document Transition Report	false
Document Quarterly Report	true
Document Type	10-Q
Document Period End Date	Jun. 30, 2023
Entity File Number	1-3701
Entity Tax Identification Number	91-0462470
Entity Address, Address Line One	1411 East Mission Avenue
Entity Address, City or Town	Spokane
Entity Address, State or Province	WA
Entity Address, Postal Zip Code	99202-2600
Local Phone Number	489-0500
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Emerging Growth Company	false
Entity Shell Company	false
Document Fiscal Year Focus	2023
Document Fiscal Period Focus	Q2
Entity Central Index Key	0000104918
Current Fiscal Year End Date	--12-31
Entity Common Stock, Shares Outstanding		76,525,146
Title of 12(b) Security	Common Stock
Trading Symbol	AVA
Security Exchange Name	NYSE

CONDENSED CONSOLIDATED STATEMEN

CONDENSED CONSOLIDATED STATEMENTS OF INCOME - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Utility revenues:
Utility revenues, exclusive of alternative revenue programs	$ 374,285	$ 384,214	$ 867,828	$ 862,917
Alternative revenue programs	5,513	(5,793)	(13,525)	(22,570)
Total utility revenues	379,798	378,421	854,303	840,347
Non-utility revenues	139	145	265	265
Total operating revenues	379,937	378,566	854,568	840,612
Utility operating expenses:
Resource costs	141,244	157,397	334,172	344,265
Other operating expenses	103,071	104,482	208,049	199,009
Depreciation and amortization	66,148	62,806	131,336	125,383
Taxes other than income taxes	24,917	26,658	58,811	60,775
Non-utility operating expenses	749	2,940	1,791	3,928
Total operating expenses	336,129	354,283	734,159	733,360
Income from operations	43,808	24,283	120,409	107,252
Capitalized interest	(866)	(932)	(1,708)	(2,025)
Other income-net	(2,626)	(13,934)	(9,055)	(18,785)
Income before income taxes	11,674	10,454	59,891	71,183
Income tax benefit	(5,810)	(999)	(12,438)	(11,835)
Net income	$ 17,484	$ 11,453	$ 72,329	$ 83,018
Weighted-average common shares outstanding (thousands), basic	75,983	72,624	75,576	72,205
Weighted-average common shares outstanding (thousands), diluted	76,131	72,658	75,703	72,294
Earnings per common share:
Basic	$ 0.23	$ 0.16	$ 0.96	$ 1.15
Diluted	$ 0.23	$ 0.16	$ 0.96	$ 1.15
Non Affiliated Trusts [Member]
Utility operating expenses:
Interest expense	$ 35,018	$ 28,518	$ 70,102	$ 56,585
Affiliated Trusts [Member]
Utility operating expenses:
Interest expense	$ 608	$ 177	$ 1,179	$ 294

CONDENSED CONSOLIDATED STATEM_2

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Net income	$ 17,484	$ 11,453	$ 72,329	$ 83,018
Other Comprehensive Income (Loss):
Change in unfunded benefit obligation for pension and other postretirement benefit plans - net of taxes of ($5), $73, ($10) and $146, respectively	(19)	273	(37)	549
Total other comprehensive income (loss)	(19)	273	(37)	549
Comprehensive income	$ 17,465	$ 11,726	$ 72,292	$ 83,567

CONDENSED CONSOLIDATED STATEM_3

CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Statement of Comprehensive Income [Abstract]
Other Comprehensive Income (Loss), Defined Benefit Plan, after Reclassification Adjustment, Tax	$ (5)	$ 73	$ (10)	$ 146

CONDENSED CONSOLIDATED BALANCE

CONDENSED CONSOLIDATED BALANCE SHEETS - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Current Assets:
Cash and cash equivalents	$ 15,704	$ 13,428
Accounts and notes receivable-less allowances of $4,871 and $6,473, respectively	141,643	255,746
Inventory	115,805	107,674
Regulatory assets	163,906	193,787
Other current assets	89,881	151,167
Total current assets	526,939	721,802
Net utility property	5,548,651	5,444,709
Goodwill	52,426	52,426
Non-current regulatory assets	861,491	833,328
Other property and investments-net and other non-current assets	381,808	365,085
Total assets	7,371,315	7,417,350
Current Liabilities:
Accounts payable	103,587	202,954
Current portion of long-term debt	7,000	13,500
Short-term borrowings	203,000	463,000
Regulatory liabilities	79,093	95,665
Other current liabilities	148,483	189,415
Total current liabilities	541,163	964,534
Pensions and other postretirement benefits	92,741	93,901
Deferred income taxes	703,683	674,995
Non-current regulatory liabilities	845,022	840,837
Other non-current liabilities and deferred credits	206,737	175,855
Total liabilities	4,970,894	5,082,682
Commitments and Contingencies (See Notes to Condensed Consolidated Financial Statements)
Shareholders' Equity:
Common stock, no par value; 200,000,000 shares authorized; 76,524,184 and 74,945,948 shares issued and outstanding, respectively	1,588,503	1,525,185
Accumulated other comprehensive loss	(2,095)	(2,058)
Retained earnings	814,013	811,541
Total shareholders’ equity	2,400,421	2,334,668
Total liabilities and equity	7,371,315	7,417,350
Non Affiliated Trusts [Member]
Current Liabilities:
Long-term debt	2,530,001	2,281,013
Affiliated Trusts [Member]
Current Liabilities:
Long-term debt	$ 51,547	$ 51,547

CONDENSED CONSOLIDATED BALANC_2

CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Statement of Financial Position [Abstract]
Accounts and notes receivable, allowances	$ 4,871	$ 6,473
Common stock, par value	$ 0	$ 0
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares, issued	76,524,184	74,945,948
Common stock, shares outstanding	76,524,184	74,945,948

CONDENSED CONSOLIDATED STATEM_4

CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Operating Activities:
Net income	$ 72,329	$ 83,018
Non-cash items included in net income:
Depreciation and amortization	131,367	125,445
Deferred income tax provision and investment tax credits	(20,565)	(12,930)
Power and natural gas cost deferrals, net	(31,559)	(19,326)
Amortization of debt expense	1,980	1,042
Stock-based compensation expense	5,460	3,646
Equity-related AFUDC	(3,172)	(3,614)
Pension and other postretirement benefit expense	6,693	10,557
Other regulatory assets and liabilities	(31,997)	9,291
Other deferred debits and credits	32,351	(3,732)
Change in decoupling regulatory deferral	14,383	22,550
Realized and unrealized loss (gain) on assets and investments	2,752	(13,144)
Other	(2,436)	4,749
Contributions to defined benefit pension plan	(6,666)	(28,000)
Cash paid for settlement of interest rate swap agreements	(409)	(17,035)
Cash received for settlement of interest rate swap agreements	7,869
Changes in certain current assets and liabilities:
Accounts and notes receivable	111,428	33,206
Inventory	(8,131)	(21,058)
Collateral posted for derivative instruments	116,602	18,131
Income taxes receivable	7,476	(168)
Other current assets	(20,228)	(1,294)
Accounts payable	(96,080)	(13,530)
Other current liabilities	(19,886)	28,137
Net cash provided by operating activities	269,561	205,941
Investing Activities:
Utility property capital expenditures (excluding equity-related AFUDC)	(226,746)	(210,646)
Issuance of notes receivable	(1,500)	(1,772)
Equity and property investments	(6,481)	(7,765)
Other	652	764
Net cash used in investing activities	(234,075)	(219,419)
Financing Activities:
Net decrease in short-term borrowings	(260,000)	(126,000)
Proceeds from issuance of long-term debt	250,000	399,856
Maturity of long-term debt and finance leases	(8,118)	(251,543)
Issuance of common stock, net of issuance costs	59,525	60,765
Cash dividends paid	(69,942)	(64,077)
Other	(4,675)	(6,072)
Net cash provided by (used in) financing activities	(33,210)	12,929
Net increase (decrease) in cash and cash equivalents	2,276	(549)
Cash and cash equivalents at beginning of period	13,428	22,168
Cash and cash equivalents at end of period	$ 15,704	$ 21,619

CONDENSED CONSOLIDATED STATEM_5

CONDENSED CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Thousands	Total	Common Stock [Member]	Accumulated Other Comprehensive Loss [Member]	Retained Earnings [Member]
Beginning Balance (in shares) at Dec. 31, 2021		71,497,523
Shares issued		1,478,559
Ending Balance (in shares) at Jun. 30, 2022		72,976,082
Beginning Balance at Dec. 31, 2021		$ 1,380,152	$ (11,039)	$ 785,631
Equity compensation expense		3,647
Issuance of common stock, net of issuance costs		60,765
Payment of minimum tax withholdings for share-based payment awards		(1,462)
Other comprehensive income (loss)	$ 549		549
Net income	83,018			83,018
Dividends on common stock				(63,767)
Ending Balance at Jun. 30, 2022	$ 2,237,494	$ 1,443,102	(10,490)	804,882
Dividends declared per common share	$ 0.88
Beginning Balance (in shares) at Mar. 31, 2022		72,438,447
Shares issued		537,635
Ending Balance (in shares) at Jun. 30, 2022		72,976,082
Beginning Balance at Mar. 31, 2022		$ 1,418,421	(10,763)	825,642
Equity compensation expense		1,802
Issuance of common stock, net of issuance costs		22,879
Other comprehensive income (loss)	$ 273		273
Net income	11,453			11,453
Dividends on common stock				(32,213)
Ending Balance at Jun. 30, 2022	$ 2,237,494	$ 1,443,102	(10,490)	804,882
Dividends declared per common share	$ 0.44
Beginning Balance (in shares) at Dec. 31, 2022	74,945,948	74,945,948
Shares issued		1,578,236
Ending Balance (in shares) at Jun. 30, 2023	76,524,184	76,524,184
Beginning Balance at Dec. 31, 2022	$ 2,334,668	$ 1,525,185	(2,058)	811,541
Equity compensation expense		5,460
Issuance of common stock, net of issuance costs		59,525
Payment of minimum tax withholdings for share-based payment awards		(1,667)
Other comprehensive income (loss)	(37)		(37)
Net income	72,329			72,329
Dividends on common stock				(69,857)
Ending Balance at Jun. 30, 2023	$ 2,400,421	$ 1,588,503	(2,095)	814,013
Dividends declared per common share	$ 0.92
Beginning Balance (in shares) at Mar. 31, 2023		75,762,598
Shares issued		761,586
Ending Balance (in shares) at Jun. 30, 2023	76,524,184	76,524,184
Beginning Balance at Mar. 31, 2023		$ 1,555,651	(2,076)	831,736
Equity compensation expense		3,239
Issuance of common stock, net of issuance costs		29,613
Other comprehensive income (loss)	$ (19)		(19)
Net income	17,484			17,484
Dividends on common stock				(35,207)
Ending Balance at Jun. 30, 2023	$ 2,400,421	$ 1,588,503	$ (2,095)	$ 814,013
Dividends declared per common share	$ 0.46

Pay vs Performance Disclosure

Pay vs Performance Disclosure - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Pay vs Performance Disclosure
Net Income (Loss)	$ 17,484	$ 11,453	$ 72,329	$ 83,018

Insider Trading Arrangements

Insider Trading Arrangements	6 Months Ended
	Jun. 30, 2023
Trading Arrangements, by Individual
Rule 10b5-1 Arrangement Adopted	false
Non-Rule 10b5-1 Arrangement Adopted	false
Rule 10b5-1 Arrangement Terminated	false
Non-Rule 10b5-1 Arrangement Terminated	false

Summary of Significant Accounti

Summary of Significant Accounting Policies	6 Months Ended
	Jun. 30, 2023
Accounting Policies [Abstract]
Summary of Significant Accounting Policies	NOTE 1. SUMMARY OF SIGNIF ICANT ACCOUNTING POLICIES Nature of Business Avista Corp. is primarily an electric and natural gas utility with certain other business ventures. Avista Utilities is an operating division of Avista Corp., comprising its regulated utility operations in the Pacific Northwest. Avista Utilities provides electric distribution and transmission, and natural gas distribution services in parts of eastern Washington and northern Idaho. Avista Utilities also provides natural gas distribution service in parts of northeastern and southwestern Oregon. Avista Utilities has electric generating facilities in Washington, Idaho, Oregon and Montana. Avista Utilities also supplies electricity to a small number of customers in Montana. AERC is a wholly-owned subsidiary of Avista Corp. The primary subsidiary of AERC is AEL&P, which comprises Avista Corp.'s regulated utility operations in Alaska. Avista Capital, a wholly owned non-regulated subsidiary of Avista Corp., is the parent company of the subsidiary companies in the non-utility businesses, with the exception of AJT Mining Properties, Inc., which is a subsidiary of AERC. See Note 17 for b usiness segment information. Basis of Reporting The condensed consolidated financial statements include the assets, liabilities, revenues and expenses of the Company and its subsidiaries and other majority owned subsidiaries and variable interest entities for which the Company or its subsidiaries are the primary beneficiaries. Intercompany balances were eliminated in consolidation. The accompanying condensed consolidated financial statements include the Company’s proportionate share of utility plant and related operations resulting from its interests in jointly owned plants. Regulation The Company is subject to state regulation in Washington, Idaho, Montana, Oregon and Alaska. The Company is also subject to federal regulation primarily by the FERC, as well as various other federal agencies with regulatory oversight of particular aspects of its operations. Derivative Assets and Liabilities Derivatives are recorded as either assets or liabilities on the Condensed Consolidated Balance Sheets measured at estimated fair value. The WUTC and the IPUC issued accounting orders authorizing Avista Corp. to offset energy commodity derivative assets or liabilities with a regulatory asset or liability. This accounting treatment is intended to defer the recognition of mark-to-market gains and losses on energy commodity transactions until the period of delivery. Realized benefits and costs result in adjustments to retail rates through PGAs, the ERM in Washington, the PCA mechanism in Idaho, and periodic general rate cases. The resulting regulatory assets associated with energy commodity derivative instruments are probable of recovery through future rates. Substantially all forward contracts to purchase or sell power and natural gas are recorded as derivative assets or liabilities at estimated fair value with an offsetting regulatory asset or liability. Contracts not considered derivatives are accounted for on the accrual basis until they are settled or realized unless there is a decline in the fair value of the contract determined to be other-than-temporary. For interest rate swap derivatives, Avista Corp. records all mark-to-market gains and losses in each accounting period as assets and liabilities, as well as offsetting regulatory assets and liabilities, such that there is no income statement impact. The interest rate swap derivatives are risk management tools similar to energy commodity derivatives. Upon settlement of interest rate swap derivatives, the regulatory asset or liability is amortized as a component of interest expense over the term of the associated debt. The Company records an offset of interest rate swap derivative assets and liabilities with regulatory assets and liabilities, based on the prior practice of the commissions to provide recovery through the ratemaking process. The Company has multiple master netting agreements with a variety of entities that allow for cross-commodity netting of derivative agreements with the same counterparty (i.e. power derivatives can be netted with natural gas derivatives). In addition, some master netting agreements allow for the netting of commodity derivatives and interest rate swap derivatives for the same counterparty. The Company does not have any agreements which allow for cross-affiliate netting among multiple affiliated legal entities. The Company nets all derivative instruments when allowed by the agreement for presentation in the Condensed Consolidated Balance Sheets. Fair Value Measurements Fair value represents the price that would be received when selling an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. Energy commodity derivative assets and liabilities, deferred compensation assets, some equity investments, as well as derivatives related to interest rate swaps and foreign currency exchange contracts, are reported at estimated fair value on the Condensed Consolidated Balance Sheets. See Note 12 for the Company’s fair value disclosures. Contingencies The Company has unresolved regulatory, legal and tax issues which have inherently uncertain outcomes. The Company accrues a loss contingency if it is probable a liability has been incurred and the amount of the loss or impairment can be reasonably estimated. The Company also discloses loss contingencies that do not meet these conditions for accrual if there is a reasonable possibility that a material loss may be incurred. See Note 16 for further discussion of the Company's commitments and contingencies.

New Accounting Standards

New Accounting Standards	6 Months Ended
	Jun. 30, 2023
Accounting Standards Update and Change in Accounting Principle [Abstract]
New Accounting Standards	NOTE 2. NEW ACCO UNTING STANDARDS ASU 2022-03 "Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions" In June 2022, the FASB issued ASU 2022-03, Fair Value Measurement (Topic 820): Fair Value Measurement of Equity Securities Subject to Contractual Sale Restrictions. The purpose of this guidance is to clarify that a contractual restriction on the ability to sell an equity security is not considered part of the unit of account of the equity security, and therefore should not be considered when measuring the equity security's fair value. Additionally, an entity cannot separately recognize and measure a contractual sale restriction. This guidance also adds specific disclosures related to equity securities subject to contractual sale restrictions, including (i) the fair value of equity securities subject to contractual sale restrictions reflected in the balance sheet and (ii) the nature and remaining duration of the restrictions, and (iii) the circumstances that could cause a lapse in the restrictions. The amendments are effective on January 1, 2024, with early adoption permitted. The amendments must be applied using a prospective approach with any adjustments from the adoption of the amendments recognized in earnings and disclosed upon adoption. The Company does not expect the impact of these amendments to be material.

Balance Sheet Components

Balance Sheet Components	6 Months Ended
	Jun. 30, 2023
Balance Sheet Related Disclosures [Abstract]
Balance Sheet Components	NOTE 3. BALANCE SHEET COMPONENTS Inventory Inventories of materials and supplies, emission allowances, fuel stock and stored natural gas are recorded at average cost and consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, 2023 2022 Materials and supplies $ 80,569 $ 75,766 Emission allowances 14,558 — Stored natural gas 14,952 26,788 Fuel stock 5,726 5,120 Total $ 115,805 $ 107,674 Other Current Assets Other current assets consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, 2023 2022 Prepayments $ 48,039 $ 30,201 Income taxes receivable 23,264 30,740 Derivative assets net of collateral 121 18,198 Collateral posted for derivative instruments after netting with outstanding 9,770 66,142 Other 8,687 5,886 Total $ 89,881 $ 151,167 Net Utility Property Net utility property, which is recorded at original cost, net of accumulated depreciation, consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, 2023 2022 Utility plant in service $ 7,619,473 $ 7,561,688 Construction work in progress 175,010 164,147 Total 7,794,483 7,725,835 Less: Accumulated depreciation and amortization 2,245,832 2,281,126 Total $ 5,548,651 $ 5,444,709 Other Property and Investments-Net and Other Non-Current Assets Other property and investments-net and other non-current assets consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, 2023 2022 Equity investments $ 149,675 $ 147,809 Operating lease ROU assets 68,594 68,238 Finance lease ROU assets 38,235 40,056 Non-utility property 30,995 25,401 Notes receivable 18,466 17,954 Long-term prepaid license fees 17,771 17,936 Pension assets 19,137 13,382 Investment in affiliated trust 11,547 11,547 Deferred compensation assets 7,428 7,541 Held for sale 3,259 — Other 16,701 15,221 Total $ 381,808 $ 365,085 Other Current Liabilities Other current liabilities consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, Accrued taxes other than income taxes $ 30,838 $ 38,568 Derivative liabilities 8,585 26,910 Employee paid time off accruals 33,022 29,279 Accrued interest 27,107 20,863 Deferred wholesale revenue — 8,481 Pensions and other postretirement benefits 13,255 15,625 Other 35,676 49,689 Total $ 148,483 $ 189,415 Other Non-Current Liabilities and Deferred Credits Other non-current liabilities and deferred credits consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, Operating lease liabilities $ 66,537 $ 64,284 Finance lease liabilities 40,795 42,495 Deferred investment tax credits 28,509 28,784 Climate Commitment Act obligations 32,994 — Asset retirement obligations 15,946 15,783 Derivative liabilities 6,044 7,892 Other 15,912 16,617 Total $ 206,737 $ 175,855 Regulatory Assets and Liabilities Regulatory assets and liabilities consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, 2023 December 31, 2022 Current Non-Current Current Non-Current Regulatory Assets Energy commodity derivatives $ 41,198 $ 18,370 $ 112,090 $ 18,185 Decoupling surcharge 4,105 3,129 6,250 5,449 Deferred natural gas costs 88,897 — 52,091 — Deferred power costs 29,706 20,527 23,356 24,043 Deferred income taxes — 240,143 — 240,325 Pension and other postretirement benefit plans — 132,530 — 135,337 Interest rate swaps — 182,793 — 185,919 AFUDC above FERC allowed rate — 50,365 — 51,649 Settlement with Coeur d'Alene Tribe — 37,251 — 37,809 Advanced meter infrastructure — 30,863 — 32,381 Utility plant abandoned — 30,563 — 24,389 Deferred Climate Commitment Act costs — 32,008 — — COVID-19 deferrals — 9,230 — 9,793 Unamortized debt repurchase costs — 5,934 — 6,177 Demand side management programs — 485 — 3,683 Other regulatory assets — 67,300 — 58,189 Total regulatory assets $ 163,906 $ 861,491 $ 193,787 $ 833,328 Regulatory Liabilities Income tax related liabilities $ 48,879 $ 365,954 $ 73,267 $ 390,734 Deferred natural gas costs 4,924 — — — Decoupling rebate 13,066 26,798 9,469 20,476 Utility plant retirement costs — 403,291 — 376,817 Interest rate swaps — 23,402 — 24,204 COVID-19 deferrals — 11,069 — 11,874 Other regulatory liabilities 12,224 14,508 12,929 16,732 Total regulatory liabilities $ 79,093 $ 845,022 $ 95,665 $ 840,837

Revenue

Revenue	6 Months Ended
	Jun. 30, 2023
Revenue from Contract with Customer [Abstract]
Revenue	NOTE 4. REVENUE The core principle of the revenue recognition accounting model is that an entity should identify the various performance obligations in a contract, allocate the transaction price among the performance obligations and recognize revenue when (or as) the entity satisfies each performance obligation. Utility Revenues Revenue from Contracts with Customers General The majority of Avista Corp.’s revenue is from rate-regulated sales of electricity and natural gas to retail customers, which has two performance obligations, (1) having service available for a specified period (typically a month at a time) and (2) the delivery of energy to customers. The total energy price generally has a fixed component (basic charge) related to having service available and a usage-based component, related to the delivery and consumption of energy. The commodity is sold and/or delivered to and consumed by the customer simultaneously, and the provisions of the relevant utility commission authorization determine the charges the Company may bill the customer. Given that all revenue recognition criteria are met upon the delivery of energy to customers, revenue is recognized immediately at that time. Revenues from contracts with customers are presented in the Condensed Consolidated Statements of Income in the line item "Utility revenues, exclusive of alternative revenue programs." Non-Derivative Wholesale Contracts The Company has certain wholesale contracts which are not accounted for as derivatives and, accordingly, are considered revenue from contracts with customers. Revenue is recognized as energy is delivered to the customer or the service is available for a specified period of time, consistent with the discussion of rate-regulated sales above. Alternative Revenue Programs (Decoupling) ASC 606 retained existing GAAP associated with alternative revenue programs, which specified alternative revenue programs are contracts between an entity and a regulator of utilities, not a contract between an entity and a customer. GAAP requires an entity to present revenue arising from alternative revenue programs separately from revenues arising from contracts with customers on the face of the Condensed Consolidated Statements of Income. The Company's decoupling mechanisms (also known as a FCA in Idaho) qualify as alternative revenue programs. Decoupling revenue deferrals are recognized in the Condensed Consolidated Statements of Income during the period they occur (i.e. during the period of revenue shortfall or excess due to fluctuations in customer usage), subject to certain limitations, and a regulatory asset or liability is established that will be surcharged or rebated to customers in future periods. GAAP requires that for any alternative revenue program, like decoupling, the revenue must be expected to be collected from customers within 24 months of the deferral to qualify for recognition in the current period Condensed Consolidated Statement of Income. Any amounts included in the Company's decoupling program not expected to be collected from customers within 24 months are not recorded in the financial statements until the period in which revenue recognition criteria are met. The amounts expected to be collected from customers within 24 months represents an estimate made by the Company on an ongoing basis due to it being based on the volumes of electric and natural gas sold to customers on a go-forward basis. The Company records alternative program revenues under the gross method, which is to amortize the decoupling regulatory asset/liability to the alternative revenue program line item on the Condensed Consolidated Statements of Income as it is collected from or refunded to customers. The cash passing between the Company and the customers is presented in revenue from contracts with customers since it is a portion of the overall tariff paid by customers. This method results in a gross-up to both revenue from contracts with customers and revenue from alternative revenue programs, but has a net zero impact on total revenue. Depending on whether the previous deferral balance being amortized was a regulatory asset or regulatory liability, and depending on the size and direction of the current year deferral of surcharges and/or rebates to customers, it could result in negative alternative revenue program revenue during the year. Derivative Revenue Most wholesale electric and natural gas transactions (including both physical and financial transactions), and the sale of fuel are considered derivatives, which are specifically excluded from revenue from contracts with customers and therefore disclosed separately. The revenue or loss is recognized for these items upon the settlement/expiration of the derivative contract. Derivative revenue includes those transactions entered into and settled within the same month. Other Utility Revenue Other utility revenue includes rent, sales of materials, late fees and other charges that do not represent contracts with customers. Other utility revenue also includes the provision for earnings sharing. This revenue is excluded from revenue from contracts with customers, as this revenue does not represent items where a customer is a party that has contracted with the Company to obtain goods or services that are an output of the Company’s ordinary activities in exchange for consideration. As such, these revenues are presented separately from revenue from contracts with customers. Other Considerations for Utility Revenues Gross Versus Net Presentation Revenues and resource costs from Avista Utilities’ settled energy contracts “booked out” (not physically delivered) are reported on a net basis as part of derivative revenues. Utility-related taxes collected from customers (primarily state excise taxes and city utility taxes) are imposed on Avista Utilities as opposed to being imposed on its customers; therefore, Avista Utilities is the taxpayer and records these transactions on a gross basis in revenue from contracts with customers and operating expense (taxes other than income taxes). The utility-related taxes collected from customers at AEL&P are imposed on the customers rather than AEL&P; therefore, the customers are the taxpayers and AEL&P is acting as their agent. As such, these transactions at AEL&P are presented on a net basis within revenue from contracts with customers. Utility-related taxes included in revenue from contracts with customers were as follows for the three and six months ended June 30 (dollars in thousands): Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Utility-related taxes $ 16,133 $ 14,908 $ 41,872 $ 37,042 Significant Judgments and Unsatisfied Performance Obligations The only significant judgments involving revenue recognition are estimates surrounding unbilled revenue and receivables from contracts with customers and estimates surrounding the amount of decoupling revenues that will be collected from customers within 24 months (discussed above). The Company has certain capacity arrangements, where the Company has a contractual obligation to provide either electric or natural gas capacity to its customers for a fixed fee. Most of these arrangements are paid for in arrears by the customers and do not result in deferred revenue and only result in receivables from the customers. The Company has one capacity agreement where the customer makes payments throughout the year. As of June 30, 2023, the Company estimates it had unsatisfied capacity performance obligations of $ 10.2 million , which will be recognized as revenue in future periods as the capacity is provided to the customers. These performance obligations are not reflected in the financial statements, as the Company has not received payment for these services. Disaggregation of Total Operating Revenue The following table disaggregates total operating revenue by segment and source for the three and six months ended June 30 (dollars in thousands): Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Avista Utilities Revenue from contracts with customers $ 294,129 $ 287,922 $ 772,904 $ 693,259 Derivative revenues 66,580 84,403 63,518 141,776 Alternative revenue programs 5,513 ( 5,793 ) ( 13,525 ) ( 22,570 ) Deferrals and amortizations for rate refunds to customers 228 ( 500 ) 645 ( 131 ) Other utility revenues 2,154 2,483 5,204 5,053 Total Avista Utilities 368,604 368,515 828,746 817,387 AEL&P Revenue from contracts with customers 11,023 10,266 25,234 23,221 Deferrals and amortizations for rate refunds to customers — ( 517 ) — ( 565 ) Other utility revenues 171 157 323 304 Total AEL&P 11,194 9,906 25,557 22,960 Other non-utility revenues 139 145 265 265 Total operating revenues $ 379,937 $ 378,566 $ 854,568 $ 840,612 Utility Revenue from Contracts with Customers by Type and Service The following table disaggregates revenue from contracts with customers associated with the Company's electric operations for the three and six months ended June 30 (dollars in thousands): 2023 2022 Avista AEL&P Total Utility Avista AEL&P Total Utility Three months ended June 30: ELECTRIC OPERATIONS Revenue from contracts with customers Residential $ 86,499 $ 4,418 $ 90,917 $ 84,108 $ 4,156 $ 88,264 Commercial 81,346 6,544 87,890 80,713 6,051 86,764 Industrial 27,956 — 27,956 27,253 — 27,253 Public street and highway lighting 1,980 61 2,041 1,912 59 1,971 Total retail revenue 197,781 11,023 208,804 193,986 10,266 204,252 Transmission 8,475 — 8,475 8,417 — 8,417 Other revenue from contracts with 6,934 — 6,934 7,409 — 7,409 Total electric revenue from contracts $ 213,190 $ 11,023 $ 224,213 $ 209,812 $ 10,266 $ 220,078 Six months ended June 30: ELECTRIC OPERATIONS Revenue from contracts with customers Residential $ 209,322 $ 11,299 $ 220,621 $ 205,111 $ 10,617 $ 215,728 Commercial 162,572 13,810 176,382 164,283 12,485 176,768 Industrial 53,123 — 53,123 52,145 — 52,145 Public street and highway lighting 3,935 125 4,060 3,776 119 3,895 Total retail revenue 428,952 25,234 454,186 425,315 23,221 448,536 Transmission 16,422 — 16,422 13,102 — 13,102 Other revenue from contracts with 24,227 — 24,227 16,171 — 16,171 Total electric revenue from contracts $ 469,601 $ 25,234 $ 494,835 $ 454,588 $ 23,221 $ 477,809 The following table disaggregates revenue from contracts with customers associated with the Company's natural gas operations for the three and six months ended June 30 (dollars in thousands): Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Avista Utilities Avista Utilities Avista Utilities Avista Utilities NATURAL GAS OPERATIONS Revenue from contracts with customers Residential $ 48,004 $ 48,480 $ 188,840 $ 151,695 Commercial 25,477 23,736 97,802 74,357 Industrial and interruptible 4,128 2,346 9,656 5,308 Total retail revenue 77,609 74,562 296,298 231,360 Transportation 1,923 2,142 4,192 4,499 Other revenue from contracts with customers 1,407 1,406 2,813 2,812 Total natural gas revenue from contracts with customers $ 80,939 $ 78,110 $ 303,303 $ 238,671

Leases

Leases	6 Months Ended
	Jun. 30, 2023
Leases [Abstract]
Leases	NOTE 5. LE ASES In March 2023, the Company entered into an agreement with Rathdrum Power, LLC (Rathdrum) amending and restating the previously existing PPA for purchase of all the output of the Lancaster plant, a 270 MW natural gas-fired combined cycle combustion turbine. The restated agreement meets the definition of a lease, and all payments are variable in nature, based on capacity, usage or performance of the plant. Therefore, there is no resulting lease obligation or corresponding ROU asset recorded by the Company. The Company previously had a variable interest in Rathdrum through the PPA, however did not consider itself the primary beneficiary of the entity. As a result of entering the amended and restated PPA, the Company reconsidered whether Rathdrum is a variable interest entity, concluding Rathdrum no longer meets the definition of a variable interest entity. This conclusion does not materially impact the Company's financial statements.

Derivatives and Risk Management

Derivatives and Risk Management	6 Months Ended
	Jun. 30, 2023
Derivative Instruments and Hedges, Assets [Abstract]
Derivatives and Risk Management	NOTE 6. DERIVATIVES AND RISK MANAGEMENT Energy Commodity Derivatives Avista Corp. is exposed to market risks relating to changes in electricity and natural gas commodity prices and certain other fuel prices. Market risk is, in general, the risk of fluctuation in the market price of the commodity being traded and is influenced primarily by supply and demand. Market risk includes the fluctuation in the market price of associated derivative commodity instruments. Avista Corp. utilizes derivative instruments, such as forwards, futures, swap derivatives and options, to manage the various risks relating to these commodity price exposures. Avista Corp. has an energy resources risk policy and control procedures to manage these risks. As part of Avista Corp.'s resource procurement and management operations in the electric business, Avista Corp. engages in an ongoing process of resource optimization, which involves the economic selection from available energy resources to serve Avista Corp.'s load obligations and the use of these resources to capture available economic value through wholesale market transactions. These include sales and purchases of electric capacity and energy, fuel for electric generation, and derivative contracts related to capacity, energy and fuel. Such transactions are part of the process of matching resources with load obligations and hedging a portion of the related financial risks. These transactions range from terms of intra-hour up to multiple years. As part of its resource procurement and management of its natural gas business, Avista Corp. makes continuing projections of its natural gas loads and assesses available natural gas resources including natural gas storage availability. Natural gas resource planning typically includes peak requirements, low and average monthly requirements and delivery constraints from natural gas supply locations to Avista Corp.’s distribution system. However, daily variations in natural gas demand can be significantly different than monthly demand projections. Based on these projections, Avista Corp. plans and executes a series of transactions to hedge a portion of its projected natural gas requirements through forward market transactions and derivative instruments. These transactions may extend as much as three natural gas operating years (November through October) into the future. Avista Corp. also leaves a significant portion of its natural gas supply requirements unhedged for purchase in short-term and spot markets. Avista Corp. plans for sufficient natural gas delivery capacity to serve its retail customers for a theoretical peak day event. Avista Corp. generally has more pipeline and storage capacity than what is needed during periods other than a peak-day. Avista Corp. optimizes its natural gas resources by using market opportunities to generate economic value that mitigates the fixed costs. Avista Corp. also optimizes its natural gas storage capacity by purchasing and storing natural gas when prices are traditionally lower, typically in the summer, and withdrawing during higher priced months, typically during the winter. However, if market conditions and prices indicate that Avista Corp. should buy or sell natural gas at other times during the year, Avista Corp. engages in optimization transactions to capture value in the marketplace. Natural gas optimization activities include, but are not limited to, wholesale market sales of surplus natural gas supplies, purchases and sales of natural gas to optimize use of pipeline and storage capacity, and participation in the transportation capacity release market. The following table presents the underlying energy commodity derivative volumes as of June 30, 2023 expected to be delivered or mature in the respective years shown (in thousands of MWhs and mmBTUs): Purchases Sales Electric Derivatives Gas Derivatives Electric Derivatives Gas Derivatives Year Physical Financial Physical Financial Physical Financial Physical Financial Remainder 2023 5 42 18,192 56,775 129 661 577 10,740 2024 — — 10,560 54,983 31 400 1,370 10,358 2025 — — 3,710 12,305 — 96 1,115 1,125 2026 — — 450 1,350 — — — — As of June 30, 2023 , there were no expected deliveries of energy commodity derivatives after 2 0 26. The following table presents the underlying energy commodity derivative volumes as of December 31, 2022 expected to be delivered or mature in the respective years shown (in thousands of MWhs and mmBTUs): Purchases Sales Electric Derivatives Gas Derivatives Electric Derivatives Gas Derivatives Year Physical Financial Physical Financial Physical Financial Physical Financial 2023 5 — 19,140 79,253 136 1,011 4,145 29,473 2024 — — 533 30,658 — — 1,370 9,668 2025 — — 450 4,895 — — 1,115 1,125 As of December 31, 2022 , there were no expected deliveries of energy commodity derivatives after 2 0 25. (1) Physical transactions represent commodity transactions in which Avista Corp. will take or make delivery of either electricity or natural gas; financial transactions represent derivative instruments with delivery of cash in the amount of the benefit or cost but with no physical delivery of the commodity, such as futures, swap derivatives, options, or forward contracts. The electric and natural gas derivative contracts above will be included in either power supply costs or natural gas supply costs during the period they are scheduled to be delivered and will be included in the various deferral and recovery mechanisms (ERM, PCA and PGAs), or in the general rate case process, and are expected to be collected through retail rates from customers. Foreign Currency Exchange Derivatives A significant portion of Avista Corp.’s natural gas supply (including fuel for power generation) is obtained from Canadian sources. Most of those transactions are executed in U.S. dollars, which avoids foreign currency risk. A portion of Avista Corp.’s short-term natural gas transactions and long-term Canadian transportation contracts are committed based on Canadian currency prices. The short-term natural gas transactions are settled within 60 days with U.S. dollars. Avista Corp. hedges a portion of the foreign currency risk by purchasing Canadian currency exchange derivatives when such commodity transactions are initiated. The foreign currency exchange derivatives and the unhedged foreign currency risk have not had a material effect on Avista Corp.’s financial condition, results of operations or cash flows and these differences in cost related to currency fluctuations are included with natural gas supply costs for ratemaking. The following table summarizes the foreign currency exchange derivatives outstanding as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, 2023 2022 Number of contracts 17 19 Notional amount (in United States dollars) $ 8,479 $ 8,563 Notional amount (in Canadian dollars) 11,255 11,659 Interest Rate Swap Derivatives Avista Corp. is affected by fluctuating interest rates related to a portion of its existing debt, and future borrowing requirements. Avista Corp. hedges a portion of its interest rate risk with financial derivative instruments, which may include interest rate swap derivatives. These interest rate swap derivatives are considered economic hedges against fluctuations in future cash flows associated with anticipated debt issuances. The following table summarizes the unsettled interest rate swap derivatives outstanding as of June 30, 2023 and December 31, 2022 (dollars in thousands): Balance Sheet Date Number of Notional Mandatory June 30, 2023 2 $ 20,000 2024 December 31, 2022 4 $ 40,000 2023 1 10,000 2024 See Note 10 for discussion of the issuance of first mortgage bonds and the related settlement of interest rate swaps in connection with the pricing of the bonds in March 2023. The fair value of outstanding interest rate swap derivatives can vary significantly from period to period depending on the total notional amount of swap derivatives outstanding and fluctuations in market interest rates compared to the interest rates fixed by the swaps. Avista Corp. is required to make cash payments to settle the interest rate swap derivatives when the fixed rates are higher than prevailing market rates at the date of settlement. Conversely, Avista Corp. receives cash to settle its interest rate swap derivatives when prevailing market rates at the time of settlement exceed the fixed swap rates. Summary of Outstanding Derivative Instruments The amounts recorded on the Condensed Consolidated Balance Sheet as of June 30, 2023 and December 31, 2022 reflect the offsetting of derivative assets and liabilities where a legal right of offset exists. The following table presents the fair values and locations of derivative instruments recorded on the Condensed Consolidated Balance Sheet as of June 30, 2023 (in thousands): Fair Value Derivative and Balance Sheet Location Gross Gross Collateral Net Asset Foreign currency exchange derivatives Other current assets $ 16 $ — $ — $ 16 Interest rate swap derivatives Other property and investments-net and other non-current assets 2,883 — — 2,883 Energy commodity derivatives Other current assets 715 ( 610 ) — 105 Other property and investments-net and other non-current assets 447 ( 282 ) — 165 Other current liabilities 27,571 ( 68,874 ) 32,718 ( 8,585 ) Other non-current liabilities and deferred credits 4,552 ( 23,087 ) 12,491 ( 6,044 ) Total derivative instruments recorded on the balance sheet $ 36,184 $ ( 92,853 ) $ 45,209 $ ( 11,460 ) The following table presents the fair values and locations of derivative instruments recorded on the Condensed Consolidated Balance Sheet as of December 31, 2022 (in thousands): Fair Value Derivative and Balance Sheet Location Gross Gross Collateral Net Asset Foreign currency exchange derivatives Other current assets $ 43 $ — $ — $ 43 Other current liabilities — ( 3 ) — ( 3 ) Interest rate swap derivatives Other current assets 8,536 — — 8,536 Other property and investments-net and other non-current assets 2,648 — — 2,648 Other current liabilities — ( 52 ) — ( 52 ) Energy commodity derivatives Other current assets 32,257 ( 22,638 ) — 9,619 Other property and investments-net and other non-current assets 312 ( 16 ) — 296 Other current liabilities 107,902 ( 229,607 ) 94,850 ( 26,855 ) Other non-current liabilities and deferred credits 6,049 ( 24,530 ) 10,589 ( 7,892 ) Total derivative instruments recorded on the balance sheet $ 157,747 $ ( 276,846 ) $ 105,439 $ ( 13,660 ) Exposure to Demands for Collateral Avista Corp.'s derivative contracts often require collateral (in the form of cash or letters of credit) or other credit enhancements, or reductions or terminations of a portion of the contract through cash settlement. In the event of a downgrade in Avista Corp.'s credit ratings or changes in market prices, additional collateral may be required. In periods of price volatility, the level of exposure can change significantly. As a result, sudden and significant demands may be made against Avista Corp.'s credit facilities and cash. Avista Corp. actively monitors the exposure to possible collateral calls and takes steps to mitigate capital requirements. The following table presents Avista Corp.'s collateral outstanding related to its derivative instruments as of June 30, 2023 and December 31, 2022 (in thousands): June 30, December 31, 2023 2022 Energy commodity derivatives Cash collateral posted $ 54,978 $ 171,581 Letters of credit outstanding 16,000 49,425 Balance sheet offsetting 45,209 105,439 No letters of credit or cash collateral were outstanding related to interest rate swap derivatives a s of June 30, 2023 and December 31, 2022. Certain of Avista Corp.’s derivative instruments contain provisions that require Avista Corp. to maintain an "investment grade" credit rating from the major credit rating agencies. If Avista Corp.’s credit ratings were to fall below "investment grade," it would be in violation of these provisions, and the counterparties to the derivative instruments could request immediate payment or demand immediate and ongoing collateralization on derivative instruments in net liability positions. The following table presents the aggregate fair value of all derivative instruments with credit-risk-related contingent features in a liability position and the amount of additional collateral Avista Corp. could be required to post as of June 30, 2023 and December 31, 2022 (in thousands): June 30, December 31, 2023 2022 Interest rate swap derivatives Liabilities with credit-risk-related contingent features $ — $ 52 Additional collateral to post — 52

Pension Plans and Other Postret

Pension Plans and Other Postretirement Benefit Plans	6 Months Ended
	Jun. 30, 2023
Retirement Benefits, Description [Abstract]
Pension Plans and Other Postretirement Benefit Plans	NOTE 7. PENSION PLANS AND OTHE R POSTRETIREMENT BENEFIT PLANS Avista Utilities The Company contributed $ 6.7 million in cash to the pension plan for the six months ended June 30, 2023, and expects to contribute $ 10.0 million in 2023. The Company uses a December 31 measurement date for its defined benefit pension and other postretirement benefit plans. The following table sets forth the components of net periodic benefit costs for the three and six months ended June 30 (dollars in thousands): Pension Benefits Other Postretirement Benefits 2023 2022 2023 2022 Three months ended June 30: Service cost $ 3,100 $ 6,229 $ 532 $ 1,097 Interest cost 8,521 6,520 1,909 1,384 Expected return on plan assets ( 10,922 ) ( 10,950 ) ( 891 ) ( 700 ) Amortization of prior service cost 123 75 ( 263 ) ( 275 ) Net loss recognition 1,185 939 ( 8 ) 870 Net periodic benefit cost $ 2,007 $ 2,813 $ 1,279 $ 2,376 Six months ended June 30: Service cost $ 7,994 $ 12,000 $ 1,350 $ 2,160 Interest cost 15,753 13,427 2,953 2,824 Expected return on plan assets ( 21,844 ) ( 21,901 ) ( 1,782 ) ( 1,400 ) Amortization of prior service cost 246 150 ( 526 ) ( 550 ) Net loss recognition 2,024 2,087 525 1,760 Net periodic benefit cost $ 4,173 $ 5,763 $ 2,520 $ 4,794 Total service costs in the table above are recognized in the same accounts as the associated labor expense. Labor and benefits expense is recorded to various projects based on whether the work is a capital project or an operating expense. Approximately 40 percent of all labor and benefits is capitalized to utility property and 60 percent is expensed to utility other operating expenses. The non-service portion of costs in the table above are recorded to other expense below income from operations in the Condensed Consolidated Statements of Income or capitalized as a regulatory asset. Approximately 40 percent of the costs are capitalized to regulatory assets and 60 percent is expensed to the income statement.

Income Taxes

Income Taxes	6 Months Ended
	Jun. 30, 2023
Income Tax Disclosure [Abstract]
Income Taxes	NOTE 8. IN COME TAXES In accordance with interim reporting requirements, the Company uses an estimated annual effective tax rate for computing its provisions for income taxes. An estimate of annual income tax expense (or benefit) is made each interim period using estimates for annual pre-tax income, income tax adjustments, and tax credits. The estimated annual effective tax rates do not include discrete events such as tax law changes, examination settlements, accounting method changes, or adjustments to tax expense or benefits attributable to prior years. Discrete events are recorded in the interim period in which they occur or become known. The estimated annual tax rate is applied to year-to-date pre-tax income to determine income tax expense (or benefit) for the interim period consistent with the annual estimate. In subsequent interim periods, income tax expense (or benefit) for the period is computed as the difference between the year-to-date amount reported for the previous interim period and the current period’s year-to-date amount. The following table summarizes the significant factors impacting the difference between the Company's effective tax rate and the federal statutory rate for the three and six months ended June 30 (dollars in thousands): Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Federal income taxes at statutory rates $ 2,452 21.0 % $ 2,195 21.0 % $ 12,577 21.0 % $ 14,948 21.0 % Increase (decrease) in tax resulting from: Flow through related to deduction of meters ( 5,689 ) ( 48.7 ) ( 2,401 ) ( 23.0 ) ( 19,212 ) ( 32.1 ) ( 19,835 ) ( 27.9 ) Tax effect of regulatory treatment of utility ( 1,525 ) ( 13.1 ) ( 976 ) ( 9.3 ) ( 5,212 ) ( 8.7 ) ( 7,298 ) ( 10.3 ) State income tax expense 232 2.0 78 0.7 798 1.3 901 1.3 Tax credits ( 1,135 ) ( 9.7 ) — — ( 1,135 ) ( 1.9 ) — — Other ( 145 ) ( 1.3 ) 105 1.0 ( 254 ) ( 0.4 ) ( 551 ) ( 0.7 ) Total income tax benefit $ ( 5,810 ) ( 49.8 )% $ ( 999 ) ( 9.6 )% $ ( 12,438 ) ( 20.8 )% $ ( 11,835 ) ( 16.6 )% (1) The Company's general rate cases included approval of base rate increases, offset by tax customer credits. As the tax customer credits are returned to customers, this results in a decrease to income tax expense as a result of flowing through the benefits related to meters and mixed service costs. The decrease in income tax expense offsets the increases in base rates granted to the Company in these general rate cases.

Short-Term Borrowings

Short-Term Borrowings	6 Months Ended
	Jun. 30, 2023
Short-Term Debt [Abstract]
Short-Term Borrowings	NOTE 9. S HORT-TERM BORROWINGS Avista Corp. Lines of Credit Avista Corp. has a committed line of credit in the total amount of $ 500 million, with an expiration date of June 2028 and the option to extend for two additional one year periods (subject to customary conditions). In June 2023, the then-existing agreement was amended to increase the capacity of the committed line of credit from $ 400 million to $ 500 million, extend the expiration date and replace the London Interbank Offered Rate (LIBOR) provisions with SOFR provisions. The committed line of credit is secured by non-transferable first mortgage bonds of Avista Corp. issued to the agent bank that would only be payable in the event, and then only to the extent, Avista Corp. defaults on its obligations under the committed line of credit. The bonds would bear interest at a rate of 12 percent. Balances outstanding and interest rates on borrowings (excluding letters of credit) under Avista Corp.’s revolving committed line of credit were as follows as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, 2023 2022 Borrowings outstanding at end of period $ 203,000 $ 313,000 Letters of credit outstanding at end of period 4,638 35,563 Average interest rate on borrowings at end of period 6.24 % 5.31 % In December 2022, Avista Corp. entered into a revolving credit agreement in the amount of $ 100 million. As of December 31, 2022, Avista Corp. did no t have any outstanding borrowings under this agreement. The agreement was terminated in June 2023 . The borrowings outstanding under Avista Corp.'s committed lines of credit were classified as short-term borrowings on the Condensed Consolidated Balance Sheets. 2022 Term Loan In December 2022, Avista Corp. entered into a term loan agreement in the amount of $ 150 million with a maturity date of March 30, 2023 . Avista Corp. borrowed the entire $ 150 million available under the agreement in 2022, and repaid the entire outstanding balance in March 2023. 2022 Letter of Credit Facility In December 2022, Avista Corp. entered into a letter of credit a greement in the aggregate amount of $ 50 million. Either party may terminate the agreement at any time. Avista Corp. had $ 16.0 million and $ 18.5 million in letters of credit outstanding under this agreement as of June 30, 2023 and December 31, 2022, respectively. Letters of credit are not reflected on the Condensed Consolidated Balance Sheets. If a letter of credit were drawn upon by the holder, we would have an immediate obligation to reimburse the bank that issued the letter. Covenants and Default Provisions The short-term borrowing agreements contain customary covenants and default provisions, including a change in control (as defined in the agreements). The events of default under each of the credit facilities also include a cross default from other indebtedness (as defined) and, in the case of the letter of credit agreement, other obligations. The committed line of credit agreement also includes a covenant which does not permit the ratio of “consolidated total debt” to “consolidated total capitalization” of Avista Corp. to be greater than 65 percent at any time. As of June 30, 2023, the Company was in compliance with this covenant. AEL&P AEL&P has a committed line of credit in the amount of $ 25.0 million that expires in June 2028 . There were no borrowings or letters of credit outstanding under this agreement as of June 30, 2023 and December 31, 2022 . The committed line of credit is secured by non-transferable first mortgage bonds of AEL&P issued to the agent bank that would only become due and payable in the event, and then only to the extent, that AEL&P defaults on its obligations under the committed line of credit.

Long-Term Debt

Long-Term Debt	6 Months Ended
	Jun. 30, 2023
Debt Disclosure [Abstract]
Long Term Debt	NOTE 10. LONG-TERM DEBT In March 2023, the Company issued and sold $ 250.0 mi llion of 5.66 percent first mortgage bonds due in 2053 with institutional investors in the private placement market. In connection with the pricing of the first mortgage bonds in March 2023, the Company cash-settled four interest rate swap derivatives (notional aggregate amount of $ 40.0 million) and received a net amount of $ 7.5 million, which will be amortized as a component of interest expense over the life of the debt. See Note 6 for a discussion of interest rate swap derivatives. A portion of the net proceeds from the sale of these bonds will be used for the construction or improvement of utility facilities, and a portion was used to refinance existing indebtedness, including the repayment of Avista Corp.'s $ 150 million term loan.

Long-Term Debt to Affiliated Tr

Long-Term Debt to Affiliated Trusts	6 Months Ended
	Jun. 30, 2023
Long Term Debt To Affiliated Trust [Abstract]
Long- Term Debt To Affiliated Trusts	NOTE 11. LONG-TERM DEB T TO AFFILIATED TRUSTS In 1997 , the Company issued Floating Rate Junior Subordinated Deferrable Interest Debentures, Series B, with a principal amount of $ 51.5 million to Avista Capital II, an affiliated business trust formed by the Company. Avista Capital II issued $ 50.0 million of Preferred Trust Securities with a floating distribution rate of LIBOR plus 0.875 percent, calculated and reset quarterly. Effective July 3, 2023, the reference to LIBOR in the formulation for the distribution rate on these securities was replaced with three-month CME Term SOFR, as calculated and published by CME Group Benchmark Administration, Ltd. (a successor administrator), plus a tenor spread adjustment of 0.26 percent. Accordingly, the distribution rate on the Preferred Trust Securities will now be the three-month CME Term SOFR plus 1.137 percent calculated and reset quarterly. The distribution rates were as follows during the six months ended June 30, 2023 and the year ended December 31, 2022: June 30, December 31, 2023 2022 Low distribution rate 5.64 % 1.05 % High distribution rate 6.37 % 5.64 % Distribution rate at the end of the period 6.37 % 5.64 % Concurrent with the issuance of the Preferred Trust Securities, Avista Capital II issued $ 1.5 million of Common Trust Securities to the Company. The Preferred Trust Securities may be redeemed at the option of Avista Capital II at any time and mature on June 1, 2037. In December 2000, the Company purchased $ 10.0 million of these Preferred Trust Securities. The Company owns 100 percent of Avista Capital II and has solely and unconditionally guaranteed the payment of distributions on, and redemption price and liquidation amount for, the Preferred Trust Securities to the extent Avista Capital II has funds available for such payments from the respective debt securities. Upon maturity or prior redemption of such debt securities, the Preferred Trust Securities will be mandatorily redeemed. The Company does not include these capital trusts in its condensed consolidated financial statements as Avista Corp. is not the primary beneficiary. As such, the sole assets of the capital trusts are $ 51.5 million of junior subordinated deferrable interest debentures of Avista Corp., which are reflected on the Condensed Consolidated Balance Sheets. Interest expense to affiliated trusts in the Condensed Consolidated Statements of Income represents interest expense on these debentures.

Fair Value

Fair Value	6 Months Ended
	Jun. 30, 2023
Fair Value Disclosures [Abstract]
Fair Value	NOTE 12. FAIR VALUE The carrying values of cash and cash equivalents, accounts and notes receivable, accounts payable, and short-term borrowings as shown on the Condensed Consolidated Balance Sheets are reasonable estimates of their fair values. The carrying values of long-term debt (including current portion and material finance leases) and long-term debt to affiliated trusts as shown on the Condensed Consolidated Balance Sheets may be different from the estimated fair value. See below for the estimated fair value of long-term debt and long-term debt to affiliated trusts. The fair value hierarchy prioritizes the inputs used to measure fair value. The hierarchy gives the highest priority to unadjusted quoted prices in active markets for identical assets or liabilities (Level 1 measurement) and the lowest priority to fair values derived from unobservable inputs (Level 3 measurement). The three levels of the fair value hierarchy are defined as follows: Level 1 – Quoted prices are available in active markets for identical assets or liabilities. Active markets are those in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis. Level 2 – Pricing inputs are other than quoted prices in active markets included in Level 1, but which are either directly or indirectly observable as of the reporting date. Level 2 includes those financial instruments valued using models or other valuation methodologies. These models are primarily industry-standard models that consider various assumptions, including quoted forward prices for commodities, time value, volatility factors, and current market and contractual prices for the underlying instruments, as well as other relevant economic measures. Substantially all of these assumptions are observable in the marketplace throughout the full term of the instrument, can be derived from observable data or are supported by observable levels at which transactions are executed in the marketplace. Level 3 – Pricing inputs include significant inputs generally unobservable from objective sources. These inputs may be used with internally developed methodologies that result in management’s best estimate of fair value. Financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The Company’s assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. The determination of the fair values incorporates various factors including the credit standing of the counterparties involved and the impact of credit enhancements (such as cash deposits and letters of credit), and the impact of Avista Corp.’s nonperformance risk on its liabilities. The following table sets forth the carrying value and estimated fair value of the Company’s financial instruments not reported at estimated fair value on the Condensed Consolidated Balance Sheets as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, 2023 December 31, 2022 Carrying Estimated Carrying Estimated Long-term debt (Level 2) $ 1,107,000 $ 975,122 $ 1,113,500 $ 966,881 Long-term debt (Level 3) 1,450,000 1,137,437 1,200,000 881,480 Snettisham finance lease obligation (Level 3) 44,113 40,500 45,730 41,700 Long-term debt to affiliated trusts (Level 3) 51,547 42,284 51,547 42,836 These estimates of fair value of long-term debt and long-term debt to affiliated trusts were primarily based on available market information, which generally consists of estimated market prices from third party brokers for debt with similar risk and terms. The price ranges obtained from the third party brokers consisted of market prices of 60.96 percent to 106.85 percent of the principal amount, where 100.0 percent of the principal amount (adjusted for unamortized discount or premium) represents the carrying value recorded on the Condensed Consolidated Balance Sheets. Level 2 long-term debt represents publicly issued bonds with quoted market prices; however, due to their limited trading activity, they are classified as Level 2 because brokers must generate quotes and make estimates if there is no trading activity near a period end. Level 3 long-term debt consists of private placement bonds and debt to affiliated trusts, which typically have no secondary trading activity. Fair values in Level 3 are estimated based on market prices from third party brokers using secondary market quotes for debt with similar risk and terms to generate quotes for Avista Corp. bonds. Due to the unique nature of the Snettisham finance lease obligation, the estimated fair value of these items was determined based on a discounted cash flow model using available market information. The Snettisham finance lease obligation was discounted to present value using the Morgan Markets A Ex-Fin discount rate as published on June 30, 2023 and December 31, 2022. The following table discloses by level within the fair value hierarchy the Company’s assets and liabilities measured and reported on the Condensed Consolidated Balance Sheets as of June 30, 2023 and December 31, 2022 at fair value on a recurring basis (dollars in thousands): Level 1 Level 2 Level 3 Counterparty Total June 30, 2023 Assets: Energy commodity derivatives $ — $ 33,285 $ — $ ( 33,015 ) $ 270 Foreign currency exchange derivatives — 16 — — 16 Interest rate swap derivatives — 2,883 — — 2,883 Equity Investments — — 48,453 — 48,453 Deferred compensation assets Mutual Funds: Fixed income securities (3) 1,142 — — — 1,142 Equity securities (3) 6,140 — — — 6,140 Total $ 7,282 $ 36,184 $ 48,453 $ ( 33,015 ) $ 58,904 Liabilities: Energy commodity derivatives (2) $ — $ 81,132 $ 11,721 $ ( 78,224 ) $ 14,629 Total $ — $ 81,132 $ 11,721 $ ( 78,224 ) $ 14,629 December 31, 2022 Assets: Energy commodity derivatives (2) $ — $ 146,232 $ 288 $ ( 136,605 ) $ 9,915 Foreign currency exchange derivatives — 43 — — 43 Interest rate swap derivatives — 11,184 — — 11,184 Equity Investments — — 54,284 — 54,284 Deferred compensation assets Mutual Funds: Fixed income securities (3) 1,267 — — — 1,267 Equity securities (3) 6,132 — — — 6,132 Total $ 7,399 $ 157,459 $ 54,572 $ ( 136,605 ) $ 82,825 Liabilities: Energy commodity derivatives (2) $ — $ 258,769 $ 18,022 $ ( 242,044 ) $ 34,747 Foreign currency exchange derivatives — 3 — — 3 Interest rate swap derivatives — 52 — — 52 Total $ — $ 258,824 $ 18,022 $ ( 242,044 ) $ 34,802 (1) The Company is permitted to net derivative assets and derivative liabilities with the same counterparty when a legally enforceable master netting agreement exists. In addition, the Company nets derivative assets and derivative liabilities against any payables and receivables for cash collateral held or placed with these same counterparties. (2) The Level 3 energy commodity derivative balances are associated with natural gas exchange agreements. (3) Included in other property and investments-net and other non-current assets on the Condensed Consolidated Balance Sheets. The difference between the amount of derivative assets and liabilities disclosed in respective levels in the table above and the amount of derivative assets and liabilities disclosed on the Condensed Consolidated Balance Sheets is due to netting arrangements with certain counterparties. See Note 6 for additional discussion of derivative netting. To establish fair value for energy commodity derivatives, the Company uses quoted market prices and forward price curves to estimate the fair value of energy commodity derivative instruments included in Level 2. In particular, electric derivative valuations are performed using market quotes, adjusted for periods in between quotable periods. Natural gas derivative valuations are estimated using New York Mercantile Exchange pricing for similar instruments, adjusted for basin differences, using market quotes. Where observable inputs are available for substantially the full term of the contract, the derivative asset or liability is included in Level 2. To establish fair values for interest rate swap derivatives, the Company uses forward market curves for interest rates for the term of the swaps and discounts the cash flows back to present value using an appropriate discount rate. The discount rate is calculated by third party brokers according to the terms of the swap derivatives and evaluated by the Company for reasonableness, with consideration given to the potential non-performance risk by the Company. Future cash flows of the interest rate swap derivatives are equal to the fixed interest rate in the swap compared to the floating market interest rate multiplied by the notional amount for each period. To establish fair value for foreign currency derivatives, the Company uses forward market curves for Canadian dollars against the US dollar and multiplies the difference between the locked-in price and the market price by the notional amount of the derivative. Forward foreign currency market curves are provided by third party brokers. The Company's credit spread is factored into the locked-in price of the foreign exchange contracts. Deferred compensation assets and liabilities represent funds held by the Company in a Rabbi Trust for an executive deferral plan. These funds consist of actively traded equity and bond funds with quoted prices in active markets. Level 3 Fair Value Natural Gas Exchange Agreement For the natural gas commodity exchange agreement, the Company uses the same Level 2 market quotes described above; however, the Company also estimates the purchase and sales volumes (within contractual limits) as well as the timing of those transactions. Changing the timing of volume estimates changes the timing of purchases and sales, impacting which brokered quote is used. Because the brokered quotes can vary significantly from period to period, the unobservable estimates of the timing and volume of transactions can have a significant impact on the calculated fair value. The Company currently estimates volumes and timing of transactions based on a most likely scenario using historical data. Historically, the timing and volume of transactions are not highly correlated with market prices and market volatility. The following table presents the quantitative information which was used to estimate the fair values of the Level 3 assets and liabilities above as of June 30, 2023 (dollars in thousands): Fair Value Valuation Unobservable Range and Weighted June 30, 2023 Technique Input Average Price Natural gas exchange agreement $ ( 11,721 ) Internally derived weighted average cost of gas Forward purchase prices $ 2.53 - $ 3.39 /mmBTU 2.99 Weighted Average Forward sales prices $ 2.92 - $ 9.53 /mmBTU 6.79 Weighted Average Purchase volumes 140,000 - 310,000 mmBTUs Sales volumes 75,000 - 310,000 mmBTUs The valuation methods, significant inputs and resulting fair values described above were developed by the Company's management and are reviewed on at least a quarterly basis to ensure they provide a reasonable estimate of fair value each reporting period. Equity Investments The Company has two equity investments measured at fair value on a recurring basis. For one investment, fair value is determined using a market approach, starting with enterprise values from recent market transaction data for comparable companies with similar equity instruments. The market transaction data was used to estimate an enterprise value of the underlying investment and that value was allocated to the various classes of equity via an option pricing model and a waterfall approach. The selection of appropriate comparable companies and the expected time to a liquidation event requires management judgment. The significant assumptions in the analysis include the comparable market transactions and related enterprise values, time to liquidity event and the market discount for lack of liquidity. In the event there are relevant market transactions for the same or similar securities of the subject company or there is the reasonable possibility of a transaction occurring, those transactions are utilized as an input to the valuation with a probability weight applied to the valuation. For the second investment, the fair value is determined using an income approach utilizing a discounted cash flow model. The model is based on income statement forecasts from the underlying company to determine cash flows for the period of ownership. The model then utilizes market multiples from publicly traded comparable companies in similar industries and projects to estimate the terminal fair value. The market multiples are reduced to reflect the difference in the life cycle between the publicly traded comparable companies and the start-up nature of the investment company. The selection of appropriate comparable companies, market multiples and the reduction to those market multiples requires management judgment. The significant assumptions in the model include the discount rate representing the risk associated with the investment, market multiples and the related reduction to those multiples, revenue forecasts, and the estimated terminal date for the investment. In the event there are relevant market transactions for the same or similar securities of the subject company or there is the reasonable possibility of a transaction occurring, those transactions are used to determine the fair value of Avista Corp.’s investment under a market approach instead of utilizing a discounted cash flow model. The market transactions are considered Level 3 inputs because they are not publicly available observable transactions. The following table presents the quantitative information which was used to estimate the fair values of the Level 3 equity investments as of June 30, 2023 (dollars in thousands): Fair Value at June 30, 2023 Valuation Technique Unobservable Input Range Equity investments $ 48,453 Market approach Comparable enterprise values $ 130,000 -$ 388,600 246,000 Average Time to liquidity event 0 to 2 years Probability weighting 75 %/ 25 % Discounted cash flows Revenue market multiples 1.39 x to 7.10 x Revenue 3.39 x Average Market exit reduction 50 % Discount rate 25 % Annual revenues $ 14,000 - $ 265,000 Terminal date 2026 The following table presents activity for assets and liabilities measured at fair value using significant unobservable inputs (Level 3) for the three and six months ended June 30 (dollars in thousands): Natural Gas Exchange Agreement (1) Equity Investments Total Three Months Ended June 30, 2023: Beginning balance $ ( 11,062 ) $ 51,014 $ 39,952 Total gains or (losses) (realized/unrealized): Included in regulatory assets/liabilities ( 1,016 ) — ( 1,016 ) Recognized in net income — ( 2,561 ) ( 2,561 ) Purchases and debt conversions — — — Settlements 357 — 357 Other — — — Ending balance as of June 30, 2023 $ ( 11,721 ) $ 48,453 $ 36,732 Three Months Ended June 30, 2022: Beginning balance $ ( 6,197 ) $ — $ ( 6,197 ) Total gains or (losses) (realized/unrealized): Included in regulatory assets/liabilities 5,196 — 5,196 Settlements ( 1,288 ) — ( 1,288 ) Ending balance as of June 30, 2022 $ ( 2,289 ) $ — $ ( 2,289 ) Six Months Ended June 30, 2023: Beginning balance $ ( 17,734 ) $ 54,284 $ 36,550 Total gains or (losses) (realized/unrealized): Included in regulatory assets/liabilities 5,767 — 5,767 Recognized in net income — ( 5,198 ) ( 5,198 ) Purchases and debt conversions — 2,367 2,367 Settlements 246 — 246 Other — ( 3,000 ) ( 3,000 ) Ending balance as of June 30, 2023 $ ( 11,721 ) $ 48,453 $ 36,732 Six Months Ended June 30, 2022: Beginning balance $ ( 7,771 ) $ — $ ( 7,771 ) Total gains or (losses) (realized/unrealized): Included in regulatory assets/liabilities 7,695 — 7,695 Settlements ( 2,213 ) — ( 2,213 ) Ending balance as of June 30, 2022 $ ( 2,289 ) $ — $ ( 2,289 ) (1) There were no purchases, issuances or transfers from other categories of any derivatives instruments during the periods presented in the table above.

Common Stock

Common Stock	6 Months Ended
	Jun. 30, 2023
Stockholders' Equity Note [Abstract]
Common Stock	NOTE 13. CO MMON STOCK The Company issued common stock for total net proceeds of $ 29.6 million and $ 59.5 million during the three and six months ended June 30, 2023, respectively. Most of these issuances came through the Company's sales agency agreements under which the Company may offer and sell new shares of common stock through its sales agents from time to time. Under these sales agency agreements, the Company issued 0.8 million and 1.5 million shares during the three and six months ended June 30, 2023 .

Accumulated Other Comprehensive

Accumulated Other Comprehensive Loss	6 Months Ended
	Jun. 30, 2023
Accumulated Other Comprehensive Loss [Abstract]
Accumulated Other Comprehensive Loss	NOTE 14. ACCUMULATED OT HER COMPREHENSIVE LOSS Accumulated other comprehensive loss, net of tax, consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, Unfunded benefit obligation for pensions and other postretirement benefit plans - 557 and $ 547 , respectively $ 2,095 $ 2,058 The following table details the reclassifications out of accumulated other comprehensive loss to net income by component for the three and six months ended June 30 (dollars in thousands): Amounts Reclassified from Accumulated Other Three months ended June 30, Six months ended June 30, Details about Accumulated Other Comprehensive Loss Components 2023 2022 2023 2022 Amortization of defined benefit pension and Amortization of net prior service cost (1) $ ( 140 ) $ ( 200 ) $ ( 280 ) $ ( 400 ) Amortization of net loss (1) 1,177 1,809 2,549 3,847 Adjustment due to effects of regulation (1) ( 1,061 ) ( 1,263 ) ( 2,316 ) ( 2,752 ) Total before tax (2) ( 24 ) 346 ( 47 ) 695 Tax expense (2) 5 ( 73 ) 10 ( 146 ) Net of tax (2) $ ( 19 ) $ 273 $ ( 37 ) $ 549 (1) These accumulated other comprehensive loss components are included in the computation of net periodic pension cost (see Note 7 for additional details). (2) Description is also the affected line item on the Condensed Consolidated Statement of Income.

Earnings Per Common Share

Earnings Per Common Share	6 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
Earnings Per Common Share	NOTE 15. EARNINGS PER COMMON SHAR E The following table presents the computation of basic and diluted earnings per common share for the three and six months ended June 30 (in thousands, except per share amounts): Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Numerator: Net income $ 17,484 $ 11,453 $ 72,329 $ 83,018 Denominator: Weighted-average number of common shares outstanding-basic 75,983 72,624 75,576 72,205 Effect of dilutive securities: Performance and restricted stock awards 148 34 127 89 Weighted-average number of common shares outstanding-diluted 76,131 72,658 75,703 72,294 Earnings per common share: Basic $ 0.23 $ 0.16 $ 0.96 $ 1.15 Diluted $ 0.23 $ 0.16 $ 0.96 $ 1.15 There were no shares excluded from the calculation because they were antidilutive.

Commitments and Contingencies

Commitments and Contingencies	6 Months Ended
	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	NOTE 16. COMMITMENT S AND CONTINGENCIES In the course of its business, the Company becomes involved in various claims, controversies, disputes and other contingent matters, including the items described in this Note. Some of these claims, controversies, disputes and other contingent matters involve litigation or other contested proceedings. For all such matters, the Company will vigorously protect and defend its interests and pursue its rights. However, no assurance can be given as to the ultimate outcome of any matter because litigation and other contested proceedings are inherently subject to numerous uncertainties. For matters affecting Avista Utilities’ or AEL&P's operations, the Company intends to seek, to the extent appropriate, recovery of incurred costs through the ratemaking process. Boyds Fire (State of Washington Department of Natural Resources (DNR) v. Avista) In August 2019, the Company was served with a complaint, captioned “State of Washington Department of Natural Resources v. Avista Corporation,” seeking recovery of up to $ 4.4 million for fire suppression and investigation costs and related expenses incurred in connection with a wildfire that occurred in Ferry County, Washington in August 2018. Specifically, the complaint alleges the fire, which became known as the “Boyds Fire,” was caused by a dead ponderosa pine tree falling into an overhead distribution line, and Avista Corp. was negligent in failing to identify and remove the tree before it came into contact with the line. Avista Corp. disputes that the tree in question was the cause of the fire and that it was negligent in failing to identify and remove it. Additional lawsuits were subsequently filed by private landowners seeking property damages, and holders of insurance subrogation claims seeking recovery of insurance proceeds paid. The lawsuits were filed in the Superior Court of Ferry County, Washington. The Company continues to vigorously defend itself in the litigation. However, at this time the Company is unable to predict the likelihood of an adverse outcome or estimate a range of potential loss in the event of such an outcome. Road 11 Fire In April 2022, Avista Corp. received a notice of claim from property owners seeking damages of $ 5 million in connection with a fire that occurred in Douglas County, Washington, in July 2020. In June 2022, those claimants filed suit in the Superior Court of Douglas County, Washington, seeking unspecified damages. The fire, which was designated as the “Road 11 Fire,” occurred in the vicinity of an Avista Corp. 115kv line, resulting in damage to three overhead transmission structures. The fire occurred during a high wind event and grew to 10,000 acres before being contained. The Company disputes that it is liable for the fire and will vigorously defend itself in the pending legal proceeding; however, at this time the Company is unable to predict the likelihood of an adverse outcome or estimate a range of potential loss in the event of such an outcome. Labor Day 2020 Windstorm General In September 2020, a severe windstorm occurred in eastern Washington and northern Idaho. The extreme weather event resulted in customer outages and multiple wildfires in the region. The Company has become aware of instances where, during the course of the storm, otherwise healthy trees and limbs, located in areas outside its maintenance right-of-way, broke under the extraordinary wind conditions and caused damage to its energy delivery system at or near what is believed to be the potential area of origin of a wildfire. Those instances include what has been referred to as: the Babb Road fire (near Malden and Pine City, Washington); the Christensen Road fire (near Airway Heights, Washington); the Mile Marker 49 fire (near Orofino, Idaho); and the Kewa Field Fire (near Colville, Washington). These wildfires covered, in total, more than 25,000 acres. The Company estimates approximately 230 residential, commercial and other structures were impacted. With respect to the Christensen Road Fire, the Mile Marker 49 Fire, and the Kewa Field Fire, the Company’s investigation determined the primary cause of the fires was extreme high winds. To date, the Company has not found any evidence that the fires were caused by any deficiencies in its equipment, maintenance activities or vegetation management practices. See further discussion below regarding the Babb Road Fire. In addition to the instances identified above, the Company is aware of a 5 -acre fire that occurred in Colfax, Washington, which damaged several residential structures. The Company's investigation determined that the Company's facilities were not involved in the ignition of this fire. The Company’s investigation has found no evidence of negligence with respect to any of the fires, and the Company will vigorously defend itself against any claims for damages that may be asserted against it with respect to the wildfires arising out of the extreme wind event; however, at this time the Company is unable to predict the likelihood of an adverse outcome or estimate a range of potential loss in the event of such an outcome. Babb Road Fire In May 2021 the Company learned the Washington Department of Natural Resources (DNR) had completed its investigation and issued a report on the Babb Road Fire. The Babb Road fire covered approximately 15,000 acres and destroyed approximately 220 structures. There are no reports of personal injury or death resulting from the fire. The DNR report concluded, among other things, that • the fire was ignited when a branch of a multi-dominant Ponderosa Pine tree was broken off by the wind and fell on an Avista Corp. distribution line; • the tree was located approximately 30 feet from the center of Avista Corp.’s distribution line and approximately 20 feet beyond Avista Corp.’s right-of-way; • the tree showed some evidence of insect damage, damage at the top of the tree from porcupines, a small area of scarring where a lateral branch/leader (LBL) had broken off in the past, and some past signs of Gall Rust disease. The DNR report concluded as follows: “It is my opinion that because of the unusual configuration of the tree, and its proximity to the powerline, a closer inspection was warranted. A nearer inspection of the tree should have revealed the cut LBL ends and its previous failure, and necessitated determination of the failure potential of the adjacent LBL, implicated in starting the Babb Road Fire.” The DNR report acknowledged that, other than the multi-dominant nature of the tree, the conditions mentioned above would not have been easily visible without close-up inspection of, or cutting into, the tree. The report also acknowledged that, while the presence of multiple tops would have been visible from the nearby roadway, the tree did not fail at a v-fork due to the presence of multiple tops. The Company contends that applicable inspection standards did not require a closer inspection of the otherwise healthy tree, nor was the Company negligent with respect to its maintenance, inspection or vegetation management practices. Nine lawsuits seeking unspecified damages have been filed in connection with the Babb Road fire. Asplundh Tree Company and CNUC Utility Consulting, which both perform vegetation management services as independent contractors to the Company, have since been added as additional defendants in each of the lawsuits. The lawsuits include six subrogation actions filed by insurance companies seeking recovery for amounts paid to insureds; two actions on behalf of individual plaintiffs; and a class action lawsuit. All proceedings were consolidated for discovery and pre-trial proceedings, are pending in the Superior Court of Spokane County Washington under the lead action Blakely v. Avista Corporation et al. , and variously assert causes of action for negligence, private nuisance, trespass and inverse condemnation (a theory of strict liability). On September 16, 2022, the Company filed a motion in the Superior Court of Spokane County, Washington, seeking dismissal of the Plaintiffs' inverse condemnation claims as a matter of law on the grounds that they are not legally cognizable under Washington law. On October 14, 2022, the Superior Court heard oral argument on that motion. The Court concluded the Company's motion involved mixed questions of law and fact, and, as a consequence, could not be granted at that stage of the proceedings; however, the Court indicated the Company could bring the issue before the Court again after discovery is completed. The Company will vigorously defend itself in the legal proceedings; however, at this time the Company is unable to predict the likelihood of an adverse outcome or estimate a range of potential loss in the event of such an outcome. Colstrip Colstrip Owners Arbitration and Litigation Colstrip Units 3 and 4 are owned by the Company, PacifiCorp, Portland General Electric (PGE), and Puget Sound Energy (PSE) (collectively, the "Western Co-Owners"), as well as NorthWestern and Talen Montana, LLC (Talen), as tenants in common under an Ownership and Operating Agreement, dated May 6, 1981, as amended (O&O Agreement), in the percentages set forth below: Co-Owner Unit 3 Unit 4 Avista 15 % 15 % PacifiCorp 10 % 10 % PGE 20 % 20 % PSE 25 % 25 % NorthWestern — 30 % Talen 30 % — Colstrip Units 1 and 2, owned by PSE and Talen, were shut down in 2020 and are in the process of being decommissioned. The co-owners of Units 3 and 4 also own undivided interests in facilities common to both Units 3 and 4, as well as in certain facilities common to all four Colstrip units. The Washington Clean Energy Transformation Act (CETA), among other things, imposes deadlines by which each electric utility must eliminate from its electricity rates in Washington the costs and benefits associated with coal-fired resources, such as Colstrip. The practical impact of CETA is electricity from such resources, including Colstrip, may no longer be delivered to Washington retail customers after 2025. The co-owners of Colstrip Units 3 and 4 have differing needs for the generating capacity of these units. Accordingly, certain business disagreements have arisen among the co-owners, including, disagreements as to the requirements for shutting down these units. NorthWestern has initiated arbitration pursuant to the O&O Agreement to resolve these business disagreements, and two actions have been initiated to compel arbitration of those disputes: one by Talen in the Montana Thirteenth Judicial District Court for Yellowstone County, and one by the Western Co-Owners, which is pending in Montana Federal District Court. In light of the ownership transfer agreements discussed below, the Colstrip owners agreed to stay both the litigation and the arbitration through September 29, 2023, at which time the proceedings would resume absent further agreement between the owners. Agreement Between Talen Energy and Puget Sound Energy In September 2022, the Company received notice that PSE and Talen entered into an agreement through which PSE has agreed to transfer its 25 percent ownership in Colstrip Units 3 and 4 to Talen at the end of 2025. The terms and conditions of the agreement are similar in most respects to the NorthWestern Transaction discussed below. Agreement Between Avista and NorthWestern On January 16, 2023, the Company entered into an agreement with NorthWestern under which the Company will transfer its 15 percent ownership in Colstrip Units 3 and 4 to NorthWestern. There is no monetary exchange included in the transaction. The transaction is scheduled to close on December 31, 2025 or such other date as the parties mutually agree upon. Under the agreement, the Company will remain obligated through the close of the transaction to pay its share of (i) operating expenses, (ii) capital expenditures, but not in excess of the portion allocable pro rata to the portion of useful life (through 2030) expired through the close of the transaction, and (iii) except for certain costs relating to post-closing activities, site remediation expenses. In addition, the Company would enter into an agreement under which it would retain its voting rights with respect to decisions relating to remediation. The Company will retain its Colstrip transmission system assets, which are excluded from the transaction. Under the Colstrip O&O Agreement, each of the other owners of Colstrip has a 90-day period in which to evaluate the transaction and determine whether to exercise their respective rights of first refusal as to a portion of the generation being turned over to NorthWestern. That period was extended, by agreement of the Owners, through September 29, 2023. The transaction is subject to the satisfaction of customary closing conditions including the receipt of any required regulatory approvals, as well as NorthWestern's ability to enter into a new coal supply agreement by December 31, 2024. The Company does not expect this transaction to have a material impact on its financial results. Burnett et al. v. Talen et al. Multiple property owners initiated a legal proceeding (titled Burnett et al. v. Talen et al. ) in the Montana District Court for Rosebud County against Talen, PSE, Pacificorp, PGE, Avista Corp., NorthWestern, and Westmoreland Rosebud Mining. The plaintiffs allege a failure to contain coal dust in connection with the operation of Colstrip, and seek unspecified damages. The Company will vigorously defend itself in the litigation, but at this time is unable to predict the outcome, nor an amount or range of potential impact in the event of an outcome adverse to the Company’s interests. Westmoreland Mine Permits Two lawsuits have been commenced by the Montana Environmental Information Center and others, challenging certain permits relating to the operation of the Westmoreland Rosebud Mine, which provides coal to Colstrip. In the first, the Montana District Court for Rosebud County issued an order vacating a permit for one area of the mine. In the second, the Montana Federal District Court vacated a decision by the federal Office of Surface Mining Reclamation and Enforcement approving expansion of the mine into a new area, pending further analysis of potential environmental impact. Both decisions have been appealed. Avista Corp. is not a party to either of these proceedings, but is continuing to monitor the progress of both lawsuits and assess the impact, if any, of the proceedings on Westmoreland’s ability to meet its contractual coal supply obligations. National Park Service (NPS) - Natural and Cultural Damage Claim In March 2017, the Company accessed property managed by the National Park Service (NPS) to prevent the imminent failure of a power pole surrounded by flood water in the Spokane River. The Company voluntarily reported its actions to the NPS several days later. Thereafter, in March 2018, the NPS notified the Company that it might seek recovery for unspecified costs and damages allegedly caused during the incident pursuant to the System Unit Resource Protection Act (SURPA), 54 U.S.C. 100721 et seq. In January 2021, the United States Department of Justice (DOJ) requested the Company and the DOJ renew discussions relating to the matter. In July 2021, the DOJ communicated that it may seek damages of approximately $ 2 million in connection with the incident for alleged damage to “natural and cultural resources”. In addition, the DOJ indicated that it may seek treble damages under the SURPA and state law, bringing its total potential claim to approximately $ 6 million. The Company disputes the position taken by the DOJ with respect to the incident, as well as the nature and extent of the DOJ’s alleged damages, and will vigorously defend itself in any litigation that may arise with respect to the matter. The Company and the DOJ have engaged in discussions to understand their respective positions and determine whether a resolution of the dispute may be possible. However, the Company cannot predict the outcome of the matter. Rathdrum, Idaho Natural Gas Incident In October 2021, there was an incident in Rathdrum, Idaho involving the Company’s natural gas infrastructure. The incident occurred after a third party damaged those facilities during excavation work. The incident resulted in a fire which destroyed one residence and resulted in minor injuries to the occupants. On January 23, 2023, the Company was served with a lawsuit filed in the District Court of Kootenai County, Idaho by one property owner, seeking unspecified damages. The Company intends to vigorously defend itself in this action. Climate Commitment Act (CCA) Obligations Effective January 1, 2023, the CCA went into effect in the State of Washington, requiring the Company to secure enough carbon allowances to cover its carbon emissions over a certain amount each year. The state has issued carbon allowances to cover electric retail sales. In May 2023, a model was approved for use in calculating the allowances needed for compliance which assumes hydroelectric generation is first used for wholesale sales, therefore reducing allowances required for wholesale sales. The Company expects to recover any costs incurred for its Washington operations through the ratemaking process. Other Contingencies In the normal course of business, the Company has various other legal claims and contingent matters outstanding. The Company believes any ultimate liability arising from these actions will not have a material impact on its financial condition, results of operations or cash flows. It is possible a change could occur in the Company’s estimates of the probability or amount of a liability being incurred. Such a change, should it occur, could be significant. See "Note 22 of the Notes to Consolidated Financial Statements" in the 2022 Form 10-K for additional discussion regarding other contingencies.

Information by Business Segment

Information by Business Segments	6 Months Ended
	Jun. 30, 2023
Segment Reporting [Abstract]
Information by Business Segments	NOTE 17. INFORMATION BY BUSINESS SEGMENTS The business segment presentation reflects the basis used by the Company's management to analyze performance and determine the allocation of resources. The Company's management evaluates performance based on income (loss) from operations before income taxes as well as net income (loss). The accounting policies of the segments are the same as those described in the summary of significant accounting policies. Avista Utilities' business is managed based on the total regulated utility operation; therefore, it is considered one segment. AEL&P is a separate reportable business segment, as it has separate financial reports reviewed in detail by the Chief Operating Decision Maker and its operations and risks are sufficiently different from Avista Utilities and the other businesses at AERC that it cannot be aggregated with any other operating segments. The Other category, which is not a reportable segment, includes other investments and operations of various subsidiaries, as well as certain other operations of Avista Capital. The following table presents information for each of the Company’s business segments (dollars in thousands): Avista Alaska Total Utility Other Intersegment Total For the three months ended June 30, 2023: Operating revenues $ 368,604 $ 11,194 $ 379,798 $ 139 $ — $ 379,937 Resource costs 140,017 1,227 141,244 — — 141,244 Other operating expenses 99,276 3,795 103,071 749 — 103,820 Depreciation and amortization 63,419 2,729 66,148 — — 66,148 Income (loss) from operations 41,257 3,161 44,418 ( 610 ) — 43,808 Interest expense (2) 34,044 1,452 35,496 448 ( 318 ) 35,626 Income taxes ( 5,556 ) 473 ( 5,083 ) ( 727 ) — ( 5,810 ) Net income (loss) 18,810 1,359 20,169 ( 2,685 ) — 17,484 Capital expenditures (3) 121,834 4,422 126,256 — — 126,256 For the three months ended June 30, 2022: Operating revenues $ 368,515 $ 9,906 $ 378,421 $ 145 $ — $ 378,566 Resource costs 156,221 1,176 157,397 — — 157,397 Other operating expenses 100,782 3,700 104,482 2,910 — 107,392 Depreciation and amortization 60,106 2,700 62,806 30 — 62,836 Income (loss) from operations 25,037 2,041 27,078 ( 2,795 ) — 24,283 Interest expense (2) 27,078 1,487 28,565 137 ( 7 ) 28,695 Income taxes ( 2,565 ) ( 211 ) ( 2,776 ) 1,777 — ( 999 ) Net income 3,950 771 4,721 6,732 — 11,453 Capital expenditures (3) 111,850 2,809 114,659 342 — 115,001 For the six months ended June 30 2023: Operating revenues $ 828,746 $ 25,557 $ 854,303 $ 265 $ — $ 854,568 Resource costs 332,154 2,018 334,172 — — 334,172 Other operating expenses 200,665 7,384 208,049 1,760 — 209,809 Depreciation and amortization 125,883 5,453 131,336 31 — 131,367 Income (loss) from operations 111,816 10,119 121,935 ( 1,526 ) — 120,409 Interest expense (2) 68,118 2,904 71,022 795 ( 536 ) 71,281 Income taxes ( 13,504 ) 2,012 ( 11,492 ) ( 946 ) — ( 12,438 ) Net income (loss) 70,437 5,401 75,838 ( 3,509 ) — 72,329 Capital expenditures (3) 219,598 7,148 226,746 3 — 226,749 For the six months ended June 30 2022: Operating revenues $ 817,387 $ 22,960 $ 840,347 $ 265 $ — $ 840,612 Resource costs 342,645 1,620 344,265 — — 344,265 Other operating expenses 191,766 7,243 199,009 3,866 — 202,875 Depreciation and amortization 119,985 5,398 125,383 62 — 125,445 Income (loss) from operations 102,816 8,099 110,915 ( 3,663 ) — 107,252 Interest expense (2) 53,650 2,974 56,624 265 ( 10 ) 56,879 Income taxes ( 14,925 ) 1,049 ( 13,876 ) 2,041 — ( 11,835 ) Net income 71,228 4,064 75,292 7,726 — 83,018 Capital expenditures (3) 207,314 3,332 210,646 756 — 211,402 Total Assets: As of June 30, 2023: $ 6,929,611 $ 270,774 $ 7,200,385 $ 189,314 $ ( 18,384 ) $ 7,371,315 As of December 31, 2022: $ 6,976,164 $ 264,322 $ 7,240,486 $ 187,027 $ ( 10,163 ) $ 7,417,350 (1) Intersegment eliminations reported as interest expense represent intercompany interest. (2) Including interest expense to affiliated trusts. (3) The capital expenditures for the other businesses are included in other investing activities on the Condensed Consolidated Statements of Cash Flows.

Summary of Significant Accoun_2

Summary of Significant Accounting Policies (Policies)	6 Months Ended
	Jun. 30, 2023
Accounting Policies [Abstract]
Nature of Business	Nature of Business Avista Corp. is primarily an electric and natural gas utility with certain other business ventures. Avista Utilities is an operating division of Avista Corp., comprising its regulated utility operations in the Pacific Northwest. Avista Utilities provides electric distribution and transmission, and natural gas distribution services in parts of eastern Washington and northern Idaho. Avista Utilities also provides natural gas distribution service in parts of northeastern and southwestern Oregon. Avista Utilities has electric generating facilities in Washington, Idaho, Oregon and Montana. Avista Utilities also supplies electricity to a small number of customers in Montana. AERC is a wholly-owned subsidiary of Avista Corp. The primary subsidiary of AERC is AEL&P, which comprises Avista Corp.'s regulated utility operations in Alaska. Avista Capital, a wholly owned non-regulated subsidiary of Avista Corp., is the parent company of the subsidiary companies in the non-utility businesses, with the exception of AJT Mining Properties, Inc., which is a subsidiary of AERC. See Note 17 for b usiness segment information.
Basis of Reporting	Basis of Reporting The condensed consolidated financial statements include the assets, liabilities, revenues and expenses of the Company and its subsidiaries and other majority owned subsidiaries and variable interest entities for which the Company or its subsidiaries are the primary beneficiaries. Intercompany balances were eliminated in consolidation. The accompanying condensed consolidated financial statements include the Company’s proportionate share of utility plant and related operations resulting from its interests in jointly owned plants.
Regulation	Regulation The Company is subject to state regulation in Washington, Idaho, Montana, Oregon and Alaska. The Company is also subject to federal regulation primarily by the FERC, as well as various other federal agencies with regulatory oversight of particular aspects of its operations.
Derivative Assets and Liabilities	Derivative Assets and Liabilities Derivatives are recorded as either assets or liabilities on the Condensed Consolidated Balance Sheets measured at estimated fair value. The WUTC and the IPUC issued accounting orders authorizing Avista Corp. to offset energy commodity derivative assets or liabilities with a regulatory asset or liability. This accounting treatment is intended to defer the recognition of mark-to-market gains and losses on energy commodity transactions until the period of delivery. Realized benefits and costs result in adjustments to retail rates through PGAs, the ERM in Washington, the PCA mechanism in Idaho, and periodic general rate cases. The resulting regulatory assets associated with energy commodity derivative instruments are probable of recovery through future rates. Substantially all forward contracts to purchase or sell power and natural gas are recorded as derivative assets or liabilities at estimated fair value with an offsetting regulatory asset or liability. Contracts not considered derivatives are accounted for on the accrual basis until they are settled or realized unless there is a decline in the fair value of the contract determined to be other-than-temporary. For interest rate swap derivatives, Avista Corp. records all mark-to-market gains and losses in each accounting period as assets and liabilities, as well as offsetting regulatory assets and liabilities, such that there is no income statement impact. The interest rate swap derivatives are risk management tools similar to energy commodity derivatives. Upon settlement of interest rate swap derivatives, the regulatory asset or liability is amortized as a component of interest expense over the term of the associated debt. The Company records an offset of interest rate swap derivative assets and liabilities with regulatory assets and liabilities, based on the prior practice of the commissions to provide recovery through the ratemaking process. The Company has multiple master netting agreements with a variety of entities that allow for cross-commodity netting of derivative agreements with the same counterparty (i.e. power derivatives can be netted with natural gas derivatives). In addition, some master netting agreements allow for the netting of commodity derivatives and interest rate swap derivatives for the same counterparty. The Company does not have any agreements which allow for cross-affiliate netting among multiple affiliated legal entities. The Company nets all derivative instruments when allowed by the agreement for presentation in the Condensed Consolidated Balance Sheets.
Fair Value Measurements	Fair Value Measurements Fair value represents the price that would be received when selling an asset or paid to transfer a liability (an exit price) in an orderly transaction between market participants at the measurement date. Energy commodity derivative assets and liabilities, deferred compensation assets, some equity investments, as well as derivatives related to interest rate swaps and foreign currency exchange contracts, are reported at estimated fair value on the Condensed Consolidated Balance Sheets. See Note 12 for the Company’s fair value disclosures.
Contingencies	Contingencies The Company has unresolved regulatory, legal and tax issues which have inherently uncertain outcomes. The Company accrues a loss contingency if it is probable a liability has been incurred and the amount of the loss or impairment can be reasonably estimated. The Company also discloses loss contingencies that do not meet these conditions for accrual if there is a reasonable possibility that a material loss may be incurred. See Note 16 for further discussion of the Company's commitments and contingencies.
Inventory	Inventories of materials and supplies, emission allowances, fuel stock and stored natural gas are recorded at average cost and consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, 2023 2022 Materials and supplies $ 80,569 $ 75,766 Emission allowances 14,558 — Stored natural gas 14,952 26,788 Fuel stock 5,726 5,120 Total $ 115,805 $ 107,674

Balance Sheet Components (Table

Balance Sheet Components (Tables)	6 Months Ended
	Jun. 30, 2023
Balance Sheet Related Disclosures [Abstract]
Schedule of Inventory	Inventories of materials and supplies, emission allowances, fuel stock and stored natural gas are recorded at average cost and consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, 2023 2022 Materials and supplies $ 80,569 $ 75,766 Emission allowances 14,558 — Stored natural gas 14,952 26,788 Fuel stock 5,726 5,120 Total $ 115,805 $ 107,674
Schedule of Other Current Assets	Other current assets consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, 2023 2022 Prepayments $ 48,039 $ 30,201 Income taxes receivable 23,264 30,740 Derivative assets net of collateral 121 18,198 Collateral posted for derivative instruments after netting with outstanding 9,770 66,142 Other 8,687 5,886 Total $ 89,881 $ 151,167
Schedule of Net Utility Property Recorded at Original Cost Net of Accumulated Depreciation	Net utility property, which is recorded at original cost, net of accumulated depreciation, consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, 2023 2022 Utility plant in service $ 7,619,473 $ 7,561,688 Construction work in progress 175,010 164,147 Total 7,794,483 7,725,835 Less: Accumulated depreciation and amortization 2,245,832 2,281,126 Total $ 5,548,651 $ 5,444,709
Other Property and Investments-Net and Other Non-Current Assets	Other property and investments-net and other non-current assets consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, 2023 2022 Equity investments $ 149,675 $ 147,809 Operating lease ROU assets 68,594 68,238 Finance lease ROU assets 38,235 40,056 Non-utility property 30,995 25,401 Notes receivable 18,466 17,954 Long-term prepaid license fees 17,771 17,936 Pension assets 19,137 13,382 Investment in affiliated trust 11,547 11,547 Deferred compensation assets 7,428 7,541 Held for sale 3,259 — Other 16,701 15,221 Total $ 381,808 $ 365,085
Other Current Liabilities	Other current liabilities consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, Accrued taxes other than income taxes $ 30,838 $ 38,568 Derivative liabilities 8,585 26,910 Employee paid time off accruals 33,022 29,279 Accrued interest 27,107 20,863 Deferred wholesale revenue — 8,481 Pensions and other postretirement benefits 13,255 15,625 Other 35,676 49,689 Total $ 148,483 $ 189,415
Schedule of Other Non-Current Liabilities and Deferred Credits	Other non-current liabilities and deferred credits consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, Operating lease liabilities $ 66,537 $ 64,284 Finance lease liabilities 40,795 42,495 Deferred investment tax credits 28,509 28,784 Climate Commitment Act obligations 32,994 — Asset retirement obligations 15,946 15,783 Derivative liabilities 6,044 7,892 Other 15,912 16,617 Total $ 206,737 $ 175,855
Schedule of Regulatory Assets and Liabilities	Regulatory assets and liabilities consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, 2023 December 31, 2022 Current Non-Current Current Non-Current Regulatory Assets Energy commodity derivatives $ 41,198 $ 18,370 $ 112,090 $ 18,185 Decoupling surcharge 4,105 3,129 6,250 5,449 Deferred natural gas costs 88,897 — 52,091 — Deferred power costs 29,706 20,527 23,356 24,043 Deferred income taxes — 240,143 — 240,325 Pension and other postretirement benefit plans — 132,530 — 135,337 Interest rate swaps — 182,793 — 185,919 AFUDC above FERC allowed rate — 50,365 — 51,649 Settlement with Coeur d'Alene Tribe — 37,251 — 37,809 Advanced meter infrastructure — 30,863 — 32,381 Utility plant abandoned — 30,563 — 24,389 Deferred Climate Commitment Act costs — 32,008 — — COVID-19 deferrals — 9,230 — 9,793 Unamortized debt repurchase costs — 5,934 — 6,177 Demand side management programs — 485 — 3,683 Other regulatory assets — 67,300 — 58,189 Total regulatory assets $ 163,906 $ 861,491 $ 193,787 $ 833,328 Regulatory Liabilities Income tax related liabilities $ 48,879 $ 365,954 $ 73,267 $ 390,734 Deferred natural gas costs 4,924 — — — Decoupling rebate 13,066 26,798 9,469 20,476 Utility plant retirement costs — 403,291 — 376,817 Interest rate swaps — 23,402 — 24,204 COVID-19 deferrals — 11,069 — 11,874 Other regulatory liabilities 12,224 14,508 12,929 16,732 Total regulatory liabilities $ 79,093 $ 845,022 $ 95,665 $ 840,837

Revenue (Tables)

Revenue (Tables)	6 Months Ended
	Jun. 30, 2023
Revenue from Contract with Customer [Abstract]
Schedule of Utilities Operating Revenue Expense Taxes	Utility-related taxes included in revenue from contracts with customers were as follows for the three and six months ended June 30 (dollars in thousands): Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Utility-related taxes $ 16,133 $ 14,908 $ 41,872 $ 37,042
Disaggregation of Revenue	Disaggregation of Total Operating Revenue The following table disaggregates total operating revenue by segment and source for the three and six months ended June 30 (dollars in thousands): Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Avista Utilities Revenue from contracts with customers $ 294,129 $ 287,922 $ 772,904 $ 693,259 Derivative revenues 66,580 84,403 63,518 141,776 Alternative revenue programs 5,513 ( 5,793 ) ( 13,525 ) ( 22,570 ) Deferrals and amortizations for rate refunds to customers 228 ( 500 ) 645 ( 131 ) Other utility revenues 2,154 2,483 5,204 5,053 Total Avista Utilities 368,604 368,515 828,746 817,387 AEL&P Revenue from contracts with customers 11,023 10,266 25,234 23,221 Deferrals and amortizations for rate refunds to customers — ( 517 ) — ( 565 ) Other utility revenues 171 157 323 304 Total AEL&P 11,194 9,906 25,557 22,960 Other non-utility revenues 139 145 265 265 Total operating revenues $ 379,937 $ 378,566 $ 854,568 $ 840,612 Utility Revenue from Contracts with Customers by Type and Service The following table disaggregates revenue from contracts with customers associated with the Company's electric operations for the three and six months ended June 30 (dollars in thousands): 2023 2022 Avista AEL&P Total Utility Avista AEL&P Total Utility Three months ended June 30: ELECTRIC OPERATIONS Revenue from contracts with customers Residential $ 86,499 $ 4,418 $ 90,917 $ 84,108 $ 4,156 $ 88,264 Commercial 81,346 6,544 87,890 80,713 6,051 86,764 Industrial 27,956 — 27,956 27,253 — 27,253 Public street and highway lighting 1,980 61 2,041 1,912 59 1,971 Total retail revenue 197,781 11,023 208,804 193,986 10,266 204,252 Transmission 8,475 — 8,475 8,417 — 8,417 Other revenue from contracts with 6,934 — 6,934 7,409 — 7,409 Total electric revenue from contracts $ 213,190 $ 11,023 $ 224,213 $ 209,812 $ 10,266 $ 220,078 Six months ended June 30: ELECTRIC OPERATIONS Revenue from contracts with customers Residential $ 209,322 $ 11,299 $ 220,621 $ 205,111 $ 10,617 $ 215,728 Commercial 162,572 13,810 176,382 164,283 12,485 176,768 Industrial 53,123 — 53,123 52,145 — 52,145 Public street and highway lighting 3,935 125 4,060 3,776 119 3,895 Total retail revenue 428,952 25,234 454,186 425,315 23,221 448,536 Transmission 16,422 — 16,422 13,102 — 13,102 Other revenue from contracts with 24,227 — 24,227 16,171 — 16,171 Total electric revenue from contracts $ 469,601 $ 25,234 $ 494,835 $ 454,588 $ 23,221 $ 477,809 The following table disaggregates revenue from contracts with customers associated with the Company's natural gas operations for the three and six months ended June 30 (dollars in thousands): Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Avista Utilities Avista Utilities Avista Utilities Avista Utilities NATURAL GAS OPERATIONS Revenue from contracts with customers Residential $ 48,004 $ 48,480 $ 188,840 $ 151,695 Commercial 25,477 23,736 97,802 74,357 Industrial and interruptible 4,128 2,346 9,656 5,308 Total retail revenue 77,609 74,562 296,298 231,360 Transportation 1,923 2,142 4,192 4,499 Other revenue from contracts with customers 1,407 1,406 2,813 2,812 Total natural gas revenue from contracts with customers $ 80,939 $ 78,110 $ 303,303 $ 238,671

Derivatives and Risk Manageme_2

Derivatives and Risk Management (Tables)	6 Months Ended
	Jun. 30, 2023
Derivative Instruments and Hedges, Assets [Abstract]
Schedule of Energy Commodity Derivative Volumes	The following table presents the underlying energy commodity derivative volumes as of June 30, 2023 expected to be delivered or mature in the respective years shown (in thousands of MWhs and mmBTUs): Purchases Sales Electric Derivatives Gas Derivatives Electric Derivatives Gas Derivatives Year Physical Financial Physical Financial Physical Financial Physical Financial Remainder 2023 5 42 18,192 56,775 129 661 577 10,740 2024 — — 10,560 54,983 31 400 1,370 10,358 2025 — — 3,710 12,305 — 96 1,115 1,125 2026 — — 450 1,350 — — — — As of June 30, 2023 , there were no expected deliveries of energy commodity derivatives after 2 0 26. The following table presents the underlying energy commodity derivative volumes as of December 31, 2022 expected to be delivered or mature in the respective years shown (in thousands of MWhs and mmBTUs): Purchases Sales Electric Derivatives Gas Derivatives Electric Derivatives Gas Derivatives Year Physical Financial Physical Financial Physical Financial Physical Financial 2023 5 — 19,140 79,253 136 1,011 4,145 29,473 2024 — — 533 30,658 — — 1,370 9,668 2025 — — 450 4,895 — — 1,115 1,125 As of December 31, 2022 , there were no expected deliveries of energy commodity derivatives after 2 0 25. (1) Physical transactions represent commodity transactions in which Avista Corp. will take or make delivery of either electricity or natural gas; financial transactions represent derivative instruments with delivery of cash in the amount of the benefit or cost but with no physical delivery of the commodity, such as futures, swap derivatives, options, or forward contracts.
Summary of Foreign Currency Exchange Derivatives	The following table summarizes the foreign currency exchange derivatives outstanding as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, 2023 2022 Number of contracts 17 19 Notional amount (in United States dollars) $ 8,479 $ 8,563 Notional amount (in Canadian dollars) 11,255 11,659
Summary of Unsettled Interest Rate Swap Derivatives	The following table summarizes the unsettled interest rate swap derivatives outstanding as of June 30, 2023 and December 31, 2022 (dollars in thousands): Balance Sheet Date Number of Notional Mandatory June 30, 2023 2 $ 20,000 2024 December 31, 2022 4 $ 40,000 2023 1 10,000 2024
Schedules of Fair Values and Locations of Derivative Instruments	The following table presents the fair values and locations of derivative instruments recorded on the Condensed Consolidated Balance Sheet as of June 30, 2023 (in thousands): Fair Value Derivative and Balance Sheet Location Gross Gross Collateral Net Asset Foreign currency exchange derivatives Other current assets $ 16 $ — $ — $ 16 Interest rate swap derivatives Other property and investments-net and other non-current assets 2,883 — — 2,883 Energy commodity derivatives Other current assets 715 ( 610 ) — 105 Other property and investments-net and other non-current assets 447 ( 282 ) — 165 Other current liabilities 27,571 ( 68,874 ) 32,718 ( 8,585 ) Other non-current liabilities and deferred credits 4,552 ( 23,087 ) 12,491 ( 6,044 ) Total derivative instruments recorded on the balance sheet $ 36,184 $ ( 92,853 ) $ 45,209 $ ( 11,460 ) The following table presents the fair values and locations of derivative instruments recorded on the Condensed Consolidated Balance Sheet as of December 31, 2022 (in thousands): Fair Value Derivative and Balance Sheet Location Gross Gross Collateral Net Asset Foreign currency exchange derivatives Other current assets $ 43 $ — $ — $ 43 Other current liabilities — ( 3 ) — ( 3 ) Interest rate swap derivatives Other current assets 8,536 — — 8,536 Other property and investments-net and other non-current assets 2,648 — — 2,648 Other current liabilities — ( 52 ) — ( 52 ) Energy commodity derivatives Other current assets 32,257 ( 22,638 ) — 9,619 Other property and investments-net and other non-current assets 312 ( 16 ) — 296 Other current liabilities 107,902 ( 229,607 ) 94,850 ( 26,855 ) Other non-current liabilities and deferred credits 6,049 ( 24,530 ) 10,589 ( 7,892 ) Total derivative instruments recorded on the balance sheet $ 157,747 $ ( 276,846 ) $ 105,439 $ ( 13,660 )
Schedule of Collateral Outstanding Related to Derivative Instruments	The following table presents Avista Corp.'s collateral outstanding related to its derivative instruments as of June 30, 2023 and December 31, 2022 (in thousands): June 30, December 31, 2023 2022 Energy commodity derivatives Cash collateral posted $ 54,978 $ 171,581 Letters of credit outstanding 16,000 49,425 Balance sheet offsetting 45,209 105,439 No letters of credit or cash collateral were outstanding related to interest rate swap derivatives a s of June 30, 2023 and December 31, 2022. Certain of Avista Corp.’s derivative instruments contain provisions that require Avista Corp. to maintain an "investment grade" credit rating from the major credit rating agencies. If Avista Corp.’s credit ratings were to fall below "investment grade," it would be in violation of these provisions, and the counterparties to the derivative instruments could request immediate payment or demand immediate and ongoing collateralization on derivative instruments in net liability positions. The following table presents the aggregate fair value of all derivative instruments with credit-risk-related contingent features in a liability position and the amount of additional collateral Avista Corp. could be required to post as of June 30, 2023 and December 31, 2022 (in thousands): June 30, December 31, 2023 2022 Interest rate swap derivatives Liabilities with credit-risk-related contingent features $ — $ 52 Additional collateral to post — 52

Pension Plans and Other Postr_2

Pension Plans and Other Postretirement Benefit Plans (Tables)	6 Months Ended
	Jun. 30, 2023
Retirement Benefits, Description [Abstract]
Components of Net Periodic Benefit Cost	The Company uses a December 31 measurement date for its defined benefit pension and other postretirement benefit plans. The following table sets forth the components of net periodic benefit costs for the three and six months ended June 30 (dollars in thousands): Pension Benefits Other Postretirement Benefits 2023 2022 2023 2022 Three months ended June 30: Service cost $ 3,100 $ 6,229 $ 532 $ 1,097 Interest cost 8,521 6,520 1,909 1,384 Expected return on plan assets ( 10,922 ) ( 10,950 ) ( 891 ) ( 700 ) Amortization of prior service cost 123 75 ( 263 ) ( 275 ) Net loss recognition 1,185 939 ( 8 ) 870 Net periodic benefit cost $ 2,007 $ 2,813 $ 1,279 $ 2,376 Six months ended June 30: Service cost $ 7,994 $ 12,000 $ 1,350 $ 2,160 Interest cost 15,753 13,427 2,953 2,824 Expected return on plan assets ( 21,844 ) ( 21,901 ) ( 1,782 ) ( 1,400 ) Amortization of prior service cost 246 150 ( 526 ) ( 550 ) Net loss recognition 2,024 2,087 525 1,760 Net periodic benefit cost $ 4,173 $ 5,763 $ 2,520 $ 4,794

Income Taxes (Tables)

Income Taxes (Tables)	6 Months Ended
	Jun. 30, 2023
Income Tax Disclosure [Abstract]
Summary of Significant Factors Impact on Difference Between Effective Tax Rate and Federal Statutory Rate	The following table summarizes the significant factors impacting the difference between the Company's effective tax rate and the federal statutory rate for the three and six months ended June 30 (dollars in thousands): Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Federal income taxes at statutory rates $ 2,452 21.0 % $ 2,195 21.0 % $ 12,577 21.0 % $ 14,948 21.0 % Increase (decrease) in tax resulting from: Flow through related to deduction of meters ( 5,689 ) ( 48.7 ) ( 2,401 ) ( 23.0 ) ( 19,212 ) ( 32.1 ) ( 19,835 ) ( 27.9 ) Tax effect of regulatory treatment of utility ( 1,525 ) ( 13.1 ) ( 976 ) ( 9.3 ) ( 5,212 ) ( 8.7 ) ( 7,298 ) ( 10.3 ) State income tax expense 232 2.0 78 0.7 798 1.3 901 1.3 Tax credits ( 1,135 ) ( 9.7 ) — — ( 1,135 ) ( 1.9 ) — — Other ( 145 ) ( 1.3 ) 105 1.0 ( 254 ) ( 0.4 ) ( 551 ) ( 0.7 ) Total income tax benefit $ ( 5,810 ) ( 49.8 )% $ ( 999 ) ( 9.6 )% $ ( 12,438 ) ( 20.8 )% $ ( 11,835 ) ( 16.6 )% (1) The Company's general rate cases included approval of base rate increases, offset by tax customer credits. As the tax customer credits are returned to customers, this results in a decrease to income tax expense as a result of flowing through the benefits related to meters and mixed service costs. The decrease in income tax expense offsets the increases in base rates granted to the Company in these general rate cases.

Short-Term Borrowings (Tables)

Short-Term Borrowings (Tables)	6 Months Ended
	Jun. 30, 2023
Avista Utilities [Member]
Line of Credit Facility [Line Items]
Schedule of Balances Outstanding and Interest Rates of Borrowings	Balances outstanding and interest rates on borrowings (excluding letters of credit) under Avista Corp.’s revolving committed line of credit were as follows as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, 2023 2022 Borrowings outstanding at end of period $ 203,000 $ 313,000 Letters of credit outstanding at end of period 4,638 35,563 Average interest rate on borrowings at end of period 6.24 % 5.31 %

Long-Term Debt to Affiliated _2

Long-Term Debt to Affiliated Trusts (Tables)	6 Months Ended
	Jun. 30, 2023
Long Term Debt To Affiliated Trust [Abstract]
Schedule of Distribution Rates	The distribution rates were as follows during the six months ended June 30, 2023 and the year ended December 31, 2022: June 30, December 31, 2023 2022 Low distribution rate 5.64 % 1.05 % High distribution rate 6.37 % 5.64 % Distribution rate at the end of the period 6.37 % 5.64 %

Fair Value (Tables)

Fair Value (Tables)	6 Months Ended
	Jun. 30, 2023
Fair Value Disclosures [Abstract]
Schedule of Carrying Value and Estimated Fair Value of Financial Instruments	The following table sets forth the carrying value and estimated fair value of the Company’s financial instruments not reported at estimated fair value on the Condensed Consolidated Balance Sheets as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, 2023 December 31, 2022 Carrying Estimated Carrying Estimated Long-term debt (Level 2) $ 1,107,000 $ 975,122 $ 1,113,500 $ 966,881 Long-term debt (Level 3) 1,450,000 1,137,437 1,200,000 881,480 Snettisham finance lease obligation (Level 3) 44,113 40,500 45,730 41,700 Long-term debt to affiliated trusts (Level 3) 51,547 42,284 51,547 42,836
Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis	The following table discloses by level within the fair value hierarchy the Company’s assets and liabilities measured and reported on the Condensed Consolidated Balance Sheets as of June 30, 2023 and December 31, 2022 at fair value on a recurring basis (dollars in thousands): Level 1 Level 2 Level 3 Counterparty Total June 30, 2023 Assets: Energy commodity derivatives $ — $ 33,285 $ — $ ( 33,015 ) $ 270 Foreign currency exchange derivatives — 16 — — 16 Interest rate swap derivatives — 2,883 — — 2,883 Equity Investments — — 48,453 — 48,453 Deferred compensation assets Mutual Funds: Fixed income securities (3) 1,142 — — — 1,142 Equity securities (3) 6,140 — — — 6,140 Total $ 7,282 $ 36,184 $ 48,453 $ ( 33,015 ) $ 58,904 Liabilities: Energy commodity derivatives (2) $ — $ 81,132 $ 11,721 $ ( 78,224 ) $ 14,629 Total $ — $ 81,132 $ 11,721 $ ( 78,224 ) $ 14,629 December 31, 2022 Assets: Energy commodity derivatives (2) $ — $ 146,232 $ 288 $ ( 136,605 ) $ 9,915 Foreign currency exchange derivatives — 43 — — 43 Interest rate swap derivatives — 11,184 — — 11,184 Equity Investments — — 54,284 — 54,284 Deferred compensation assets Mutual Funds: Fixed income securities (3) 1,267 — — — 1,267 Equity securities (3) 6,132 — — — 6,132 Total $ 7,399 $ 157,459 $ 54,572 $ ( 136,605 ) $ 82,825 Liabilities: Energy commodity derivatives (2) $ — $ 258,769 $ 18,022 $ ( 242,044 ) $ 34,747 Foreign currency exchange derivatives — 3 — — 3 Interest rate swap derivatives — 52 — — 52 Total $ — $ 258,824 $ 18,022 $ ( 242,044 ) $ 34,802 (1) The Company is permitted to net derivative assets and derivative liabilities with the same counterparty when a legally enforceable master netting agreement exists. In addition, the Company nets derivative assets and derivative liabilities against any payables and receivables for cash collateral held or placed with these same counterparties. (2) The Level 3 energy commodity derivative balances are associated with natural gas exchange agreements. (3) Included in other property and investments-net and other non-current assets on the Condensed Consolidated Balance Sheets.
Schedule of Quantitative Information	The following table presents the quantitative information which was used to estimate the fair values of the Level 3 assets and liabilities above as of June 30, 2023 (dollars in thousands): Fair Value Valuation Unobservable Range and Weighted June 30, 2023 Technique Input Average Price Natural gas exchange agreement $ ( 11,721 ) Internally derived weighted average cost of gas Forward purchase prices $ 2.53 - $ 3.39 /mmBTU 2.99 Weighted Average Forward sales prices $ 2.92 - $ 9.53 /mmBTU 6.79 Weighted Average Purchase volumes 140,000 - 310,000 mmBTUs Sales volumes 75,000 - 310,000 mmBTUs The following table presents the quantitative information which was used to estimate the fair values of the Level 3 equity investments as of June 30, 2023 (dollars in thousands): Fair Value at June 30, 2023 Valuation Technique Unobservable Input Range Equity investments $ 48,453 Market approach Comparable enterprise values $ 130,000 -$ 388,600 246,000 Average Time to liquidity event 0 to 2 years Probability weighting 75 %/ 25 % Discounted cash flows Revenue market multiples 1.39 x to 7.10 x Revenue 3.39 x Average Market exit reduction 50 % Discount rate 25 % Annual revenues $ 14,000 - $ 265,000 Terminal date 2026
Schedule of Activity for Natural Gas Exchange Agreement Derivative Assets (Liabilities) Measured At Fair Value Using Significant Unobservable Inputs (Level 3)	The following table presents activity for assets and liabilities measured at fair value using significant unobservable inputs (Level 3) for the three and six months ended June 30 (dollars in thousands): Natural Gas Exchange Agreement (1) Equity Investments Total Three Months Ended June 30, 2023: Beginning balance $ ( 11,062 ) $ 51,014 $ 39,952 Total gains or (losses) (realized/unrealized): Included in regulatory assets/liabilities ( 1,016 ) — ( 1,016 ) Recognized in net income — ( 2,561 ) ( 2,561 ) Purchases and debt conversions — — — Settlements 357 — 357 Other — — — Ending balance as of June 30, 2023 $ ( 11,721 ) $ 48,453 $ 36,732 Three Months Ended June 30, 2022: Beginning balance $ ( 6,197 ) $ — $ ( 6,197 ) Total gains or (losses) (realized/unrealized): Included in regulatory assets/liabilities 5,196 — 5,196 Settlements ( 1,288 ) — ( 1,288 ) Ending balance as of June 30, 2022 $ ( 2,289 ) $ — $ ( 2,289 ) Six Months Ended June 30, 2023: Beginning balance $ ( 17,734 ) $ 54,284 $ 36,550 Total gains or (losses) (realized/unrealized): Included in regulatory assets/liabilities 5,767 — 5,767 Recognized in net income — ( 5,198 ) ( 5,198 ) Purchases and debt conversions — 2,367 2,367 Settlements 246 — 246 Other — ( 3,000 ) ( 3,000 ) Ending balance as of June 30, 2023 $ ( 11,721 ) $ 48,453 $ 36,732 Six Months Ended June 30, 2022: Beginning balance $ ( 7,771 ) $ — $ ( 7,771 ) Total gains or (losses) (realized/unrealized): Included in regulatory assets/liabilities 7,695 — 7,695 Settlements ( 2,213 ) — ( 2,213 ) Ending balance as of June 30, 2022 $ ( 2,289 ) $ — $ ( 2,289 ) (1) There were no purchases, issuances or transfers from other categories of any derivatives instruments during the periods presented in the table above.

Accumulated Other Comprehensi_2

Accumulated Other Comprehensive Loss (Tables)	6 Months Ended
	Jun. 30, 2023
Accumulated Other Comprehensive Loss [Abstract]
Schedule of Accumulated Other Comprehensive Loss, Net of Tax	Accumulated other comprehensive loss, net of tax, consisted of the following as of June 30, 2023 and December 31, 2022 (dollars in thousands): June 30, December 31, Unfunded benefit obligation for pensions and other postretirement benefit plans - 557 and $ 547 , respectively $ 2,095 $ 2,058
Reclassification out of Accumulated Other Comprehensive Loss	The following table details the reclassifications out of accumulated other comprehensive loss to net income by component for the three and six months ended June 30 (dollars in thousands): Amounts Reclassified from Accumulated Other Three months ended June 30, Six months ended June 30, Details about Accumulated Other Comprehensive Loss Components 2023 2022 2023 2022 Amortization of defined benefit pension and Amortization of net prior service cost (1) $ ( 140 ) $ ( 200 ) $ ( 280 ) $ ( 400 ) Amortization of net loss (1) 1,177 1,809 2,549 3,847 Adjustment due to effects of regulation (1) ( 1,061 ) ( 1,263 ) ( 2,316 ) ( 2,752 ) Total before tax (2) ( 24 ) 346 ( 47 ) 695 Tax expense (2) 5 ( 73 ) 10 ( 146 ) Net of tax (2) $ ( 19 ) $ 273 $ ( 37 ) $ 549 (1) These accumulated other comprehensive loss components are included in the computation of net periodic pension cost (see Note 7 for additional details). (2) Description is also the affected line item on the Condensed Consolidated Statement of Income.

Earnings Per Common Share (Tabl

Earnings Per Common Share (Tables)	6 Months Ended
	Jun. 30, 2023
Earnings Per Share [Abstract]
Schedule of Computation of Basic and Diluted Earnings Per Common Share	The following table presents the computation of basic and diluted earnings per common share for the three and six months ended June 30 (in thousands, except per share amounts): Three months ended June 30, Six months ended June 30, 2023 2022 2023 2022 Numerator: Net income $ 17,484 $ 11,453 $ 72,329 $ 83,018 Denominator: Weighted-average number of common shares outstanding-basic 75,983 72,624 75,576 72,205 Effect of dilutive securities: Performance and restricted stock awards 148 34 127 89 Weighted-average number of common shares outstanding-diluted 76,131 72,658 75,703 72,294 Earnings per common share: Basic $ 0.23 $ 0.16 $ 0.96 $ 1.15 Diluted $ 0.23 $ 0.16 $ 0.96 $ 1.15

Commitments and Contingencies (

Commitments and Contingencies (Tables)	6 Months Ended
	Jun. 30, 2023
Commitments and Contingencies Disclosure [Abstract]
Ownership and Operating Ownership Interest Percentage	Colstrip Units 3 and 4 are owned by the Company, PacifiCorp, Portland General Electric (PGE), and Puget Sound Energy (PSE) (collectively, the "Western Co-Owners"), as well as NorthWestern and Talen Montana, LLC (Talen), as tenants in common under an Ownership and Operating Agreement, dated May 6, 1981, as amended (O&O Agreement), in the percentages set forth below: Co-Owner Unit 3 Unit 4 Avista 15 % 15 % PacifiCorp 10 % 10 % PGE 20 % 20 % PSE 25 % 25 % NorthWestern — 30 % Talen 30 % —

Information by Business Segme_2

Information by Business Segments (Tables)	6 Months Ended
	Jun. 30, 2023
Segment Reporting [Abstract]
Schedule of Business Segments	The following table presents information for each of the Company’s business segments (dollars in thousands): Avista Alaska Total Utility Other Intersegment Total For the three months ended June 30, 2023: Operating revenues $ 368,604 $ 11,194 $ 379,798 $ 139 $ — $ 379,937 Resource costs 140,017 1,227 141,244 — — 141,244 Other operating expenses 99,276 3,795 103,071 749 — 103,820 Depreciation and amortization 63,419 2,729 66,148 — — 66,148 Income (loss) from operations 41,257 3,161 44,418 ( 610 ) — 43,808 Interest expense (2) 34,044 1,452 35,496 448 ( 318 ) 35,626 Income taxes ( 5,556 ) 473 ( 5,083 ) ( 727 ) — ( 5,810 ) Net income (loss) 18,810 1,359 20,169 ( 2,685 ) — 17,484 Capital expenditures (3) 121,834 4,422 126,256 — — 126,256 For the three months ended June 30, 2022: Operating revenues $ 368,515 $ 9,906 $ 378,421 $ 145 $ — $ 378,566 Resource costs 156,221 1,176 157,397 — — 157,397 Other operating expenses 100,782 3,700 104,482 2,910 — 107,392 Depreciation and amortization 60,106 2,700 62,806 30 — 62,836 Income (loss) from operations 25,037 2,041 27,078 ( 2,795 ) — 24,283 Interest expense (2) 27,078 1,487 28,565 137 ( 7 ) 28,695 Income taxes ( 2,565 ) ( 211 ) ( 2,776 ) 1,777 — ( 999 ) Net income 3,950 771 4,721 6,732 — 11,453 Capital expenditures (3) 111,850 2,809 114,659 342 — 115,001 For the six months ended June 30 2023: Operating revenues $ 828,746 $ 25,557 $ 854,303 $ 265 $ — $ 854,568 Resource costs 332,154 2,018 334,172 — — 334,172 Other operating expenses 200,665 7,384 208,049 1,760 — 209,809 Depreciation and amortization 125,883 5,453 131,336 31 — 131,367 Income (loss) from operations 111,816 10,119 121,935 ( 1,526 ) — 120,409 Interest expense (2) 68,118 2,904 71,022 795 ( 536 ) 71,281 Income taxes ( 13,504 ) 2,012 ( 11,492 ) ( 946 ) — ( 12,438 ) Net income (loss) 70,437 5,401 75,838 ( 3,509 ) — 72,329 Capital expenditures (3) 219,598 7,148 226,746 3 — 226,749 For the six months ended June 30 2022: Operating revenues $ 817,387 $ 22,960 $ 840,347 $ 265 $ — $ 840,612 Resource costs 342,645 1,620 344,265 — — 344,265 Other operating expenses 191,766 7,243 199,009 3,866 — 202,875 Depreciation and amortization 119,985 5,398 125,383 62 — 125,445 Income (loss) from operations 102,816 8,099 110,915 ( 3,663 ) — 107,252 Interest expense (2) 53,650 2,974 56,624 265 ( 10 ) 56,879 Income taxes ( 14,925 ) 1,049 ( 13,876 ) 2,041 — ( 11,835 ) Net income 71,228 4,064 75,292 7,726 — 83,018 Capital expenditures (3) 207,314 3,332 210,646 756 — 211,402 Total Assets: As of June 30, 2023: $ 6,929,611 $ 270,774 $ 7,200,385 $ 189,314 $ ( 18,384 ) $ 7,371,315 As of December 31, 2022: $ 6,976,164 $ 264,322 $ 7,240,486 $ 187,027 $ ( 10,163 ) $ 7,417,350 (1) Intersegment eliminations reported as interest expense represent intercompany interest. (2) Including interest expense to affiliated trusts. (3) The capital expenditures for the other businesses are included in other investing activities on the Condensed Consolidated Statements of Cash Flows.

Balance Sheet Components - Sche

Balance Sheet Components - Schedule of Inventory (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Materials and supplies	$ 80,569	$ 75,766
Emission allowances	14,558
Stored natural gas	14,952	26,788
Fuel stock	5,726	5,120
Total	$ 115,805	$ 107,674

Balance Sheet Components - Sc_2

Balance Sheet Components - Schedule of Other Current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Prepayments	$ 48,039	$ 30,201
Income taxes receivable	23,264	30,740
Derivative assets net of collateral	121	18,198
Collateral posted for derivative instruments after netting with outstanding derivative	9,770	66,142
Other	8,687	5,886
Total	$ 89,881	$ 151,167

Balance Sheet Components - Sc_3

Balance Sheet Components - Schedule of Net Utility Property Recorded at Original Cost Net of Accumulated Depreciation (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Utility plant in service	$ 7,619,473	$ 7,561,688
Construction work in progress	175,010	164,147
Total	7,794,483	7,725,835
Less: Accumulated depreciation and amortization	2,245,832	2,281,126
Total	$ 5,548,651	$ 5,444,709

Balance Sheet Components - Othe

Balance Sheet Components - Other Property and Investments-Net and Other Non-current Assets (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Equity investments	$ 149,675	$ 147,809
Operating lease ROU assets	$ 68,594	$ 68,238
Operating Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Total	Total
Finance lease ROU assets	$ 38,235	$ 40,056
Finance Lease, Right-of-Use Asset, Statement of Financial Position [Extensible Enumeration]	Total	Total
Non-utility property	$ 30,995	$ 25,401
Notes receivable	18,466	17,954
Long-term prepaid license fees	17,771	17,936
Pension assets	19,137	13,382
Investment in affiliated trust	11,547	11,547
Deferred compensation assets	7,428	7,541
Held for sale	3,259
Other	16,701	15,221
Total	$ 381,808	$ 365,085

Balance Sheet Components - Ot_2

Balance Sheet Components - Other Current Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Accrued taxes other than income taxes	$ 30,838	$ 38,568
Derivative liabilities	8,585	26,910
Employee paid time off accruals	33,022	29,279
Accrued interest	27,107	20,863
Deferred wholesale revenue		8,481
Pensions and other postretirement benefits	13,255	15,625
Other	35,676	49,689
Total	$ 148,483	$ 189,415

Balance Sheet Components - Sc_4

Balance Sheet Components - Schedule of Other Non-Current Liabilities and Deferred Credits (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Balance Sheet Related Disclosures [Abstract]
Operating lease liabilities	$ 66,537	$ 64,284
Operating Lease, Liability, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Total	Total
Finance lease liabilities	$ 40,795	$ 42,495
Deferred investment tax credits	28,509	28,784
Climate Commitment Act Obligations	32,994
Asset retirement obligations	15,946	15,783
Derivative liabilities	6,044	7,892
Other	15,912	16,617
Total	$ 206,737	$ 175,855

Balance Sheet Components - Sc_5

Balance Sheet Components - Schedule of Regulatory Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	$ 163,906	$ 193,787
Regulatory Assets, Non-Current	861,491	833,328
Regulatory Liabilities, Current	79,093	95,665
Regulatory Liabilities, Non-Current	845,022	840,837
Income Tax Related Liabilities [Member]
Regulated Asset Liability [Line Items]
Regulatory Liabilities, Current	48,879	73,267
Regulatory Liabilities, Non-Current	365,954	390,734
Deferred Natural Gas Costs [Member]
Regulated Asset Liability [Line Items]
Regulatory Liabilities, Current	4,924	0
Regulatory Liabilities, Non-Current	0	0
Decoupling Rebate [Member]
Regulated Asset Liability [Line Items]
Regulatory Liabilities, Current	13,066	9,469
Regulatory Liabilities, Non-Current	26,798	20,476
Utility Plant Retirement Costs [Member]
Regulated Asset Liability [Line Items]
Regulatory Liabilities, Current	0	0
Regulatory Liabilities, Non-Current	403,291	376,817
Interest Rate Swaps [Member]
Regulated Asset Liability [Line Items]
Regulatory Liabilities, Current	0	0
Regulatory Liabilities, Non-Current	23,402	24,204
COVID-19 Deferrals [Member]
Regulated Asset Liability [Line Items]
Regulatory Liabilities, Current	0	0
Regulatory Liabilities, Non-Current	11,069	11,874
Other Regulatory Liabilities [Member]
Regulated Asset Liability [Line Items]
Regulatory Liabilities, Current	12,224	12,929
Regulatory Liabilities, Non-Current	14,508	16,732
Energy Commodity Derivatives [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	41,198	112,090
Regulatory Assets, Non-Current	18,370	18,185
Decoupling Surcharge [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	4,105	6,250
Regulatory Assets, Non-Current	3,129	5,449
Deferred Natural Gas Costs [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	88,897	52,091
Regulatory Assets, Non-Current	0	0
Deferred Power Costs [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	29,706	23,356
Regulatory Assets, Non-Current	20,527	24,043
Deferred Income Taxes [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	0	0
Regulatory Assets, Non-Current	240,143	240,325
Pension and Other Postretirement Benefit Plans [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	0	0
Regulatory Assets, Non-Current	132,530	135,337
Interest Rate Swaps [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	0	0
Regulatory Assets, Non-Current	182,793	185,919
AFUDC Above FERC Allowed Rate [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	0	0
Regulatory Assets, Non-Current	50,365	51,649
Settlement with Coeur d'Alene Tribe [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	0	0
Regulatory Assets, Non-Current	37,251	37,809
Advanced Meter Infrastructure [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	0	0
Regulatory Assets, Non-Current	30,863	32,381
Utility Plant Abandoned [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	0	0
Regulatory Assets, Non-Current	30,563	24,389
Deferred Climate Commitment Act Costs [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	0	0
Regulatory Assets, Non-Current	32,008	0
COVID-19 Deferrals [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	0	0
Regulatory Assets, Non-Current	9,230	9,793
Unamortized Debt Repurchase Costs [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	0	0
Regulatory Assets, Non-Current	5,934	6,177
Demand Side Management Programs [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	0	0
Regulatory Assets, Non-Current	485	3,683
Other Regulatory Assets [Member]
Regulated Asset Liability [Line Items]
Regulatory Assets, Current	0	0
Regulatory Assets, Non-Current	$ 67,300	$ 58,189

Revenue - Schedule of Utilities

Revenue - Schedule of Utilities Operating Revenue Expense Taxes (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Revenue from Contract with Customer [Abstract]
Utility-related taxes	$ 16,133	$ 14,908	$ 41,872	$ 37,042

Revenue - Additional Informatio

Revenue - Additional Information (Details) $ in Millions	Jun. 30, 2023 USD ($)
Revenue from Contract with Customer [Abstract]
Revenue, Remaining Performance Obligation, Amount	$ 10.2

Revenue - Disaggregation of Rev

Revenue - Disaggregation of Revenue (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Disaggregation of Revenue [Line Items]
Revenues	$ 379,937	$ 378,566	$ 854,568	$ 840,612
Residential Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	90,917	88,264	220,621	215,728
Commercial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	87,890	86,764	176,382	176,768
Industrial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	27,956	27,253	53,123	52,145
Public Street and Highway Lighting Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	2,041	1,971	4,060	3,895
Retail Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	208,804	204,252	454,186	448,536
Transmission Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	8,475	8,417	16,422	13,102
Other Electric Revenues from Contracts With Customers [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	6,934	7,409	24,227	16,171
Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	224,213	220,078	494,835	477,809
Avista Utilities [Member]
Disaggregation of Revenue [Line Items]
Revenues	368,604	368,515	828,746	817,387
Avista Utilities [Member] | Residential Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	86,499	84,108	209,322	205,111
Avista Utilities [Member] | Commercial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	81,346	80,713	162,572	164,283
Avista Utilities [Member] | Industrial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	27,956	27,253	53,123	52,145
Avista Utilities [Member] | Public Street and Highway Lighting Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	1,980	1,912	3,935	3,776
Avista Utilities [Member] | Retail Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	197,781	193,986	428,952	425,315
Avista Utilities [Member] | Transmission Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	8,475	8,417	16,422	13,102
Avista Utilities [Member] | Other Electric Revenues from Contracts With Customers [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	6,934	7,409	24,227	16,171
Avista Utilities [Member] | Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	213,190	209,812	469,601	454,588
Avista Utilities [Member] | Residential Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	48,004	48,480	188,840	151,695
Avista Utilities [Member] | Commercial Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	25,477	23,736	97,802	74,357
Avista Utilities [Member] | Industrial and Interruptible Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	4,128	2,346	9,656	5,308
Avista Utilities [Member] | Retail Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	77,609	74,562	296,298	231,360
Avista Utilities [Member] | Transportation Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	1,923	2,142	4,192	4,499
Avista Utilities [Member] | Other Natural Gas Revenues from Contracts With Customers [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	1,407	1,406	2,813	2,812
Avista Utilities [Member] | Natural Gas [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	80,939	78,110	303,303	238,671
Avista Utilities [Member] | Revenue from Contracts with Customers [Member]
Disaggregation of Revenue [Line Items]
Revenues	294,129	287,922	772,904	693,259
Avista Utilities [Member] | Derivative revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	66,580	84,403	63,518	141,776
Avista Utilities [Member] | Alternative Revenue Programs [Member]
Disaggregation of Revenue [Line Items]
Revenues	5,513	(5,793)	(13,525)	(22,570)
Avista Utilities [Member] | Deferrals and Amortizations for Rate Refunds to Customers [Member]
Disaggregation of Revenue [Line Items]
Revenues	228	(500)	645	(131)
Avista Utilities [Member] | Other Utility Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	2,154	2,483	5,204	5,053
Alaska Electric Light & Power [Member]
Disaggregation of Revenue [Line Items]
Revenues	11,194	9,906	25,557	22,960
Alaska Electric Light & Power [Member] | Residential Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	4,418	4,156	11,299	10,617
Alaska Electric Light & Power [Member] | Commercial Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	6,544	6,051	13,810	12,485
Alaska Electric Light & Power [Member] | Public Street and Highway Lighting Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	61	59	125	119
Alaska Electric Light & Power [Member] | Retail Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	11,023	10,266	25,234	23,221
Alaska Electric Light & Power [Member] | Electric [Member]
Disaggregation of Revenue [Line Items]
Revenue from contract with customer including assessed tax	11,023	10,266	25,234	23,221
Alaska Electric Light & Power [Member] | Revenue from Contracts with Customers [Member]
Disaggregation of Revenue [Line Items]
Revenues	11,023	10,266	25,234	23,221
Alaska Electric Light & Power [Member] | Deferrals and Amortizations for Rate Refunds to Customers [Member]
Disaggregation of Revenue [Line Items]
Revenues		(517)		(565)
Alaska Electric Light & Power [Member] | Other Utility Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	171	157	323	304
Corporate and Other [Member] | Other Utility Revenues [Member]
Disaggregation of Revenue [Line Items]
Revenues	$ 139	$ 145	$ 265	$ 265

Leases - Additional Information

Leases - Additional Information (Details)	6 Months Ended
	Jun. 30, 2023 MW
Lancaster Power Purchase Agreement [Member]
Lessee, Lease, Description [Line Items]
Evaluated Power Capacity	270

Derivatives and Risk Manageme_3

Derivatives and Risk Management - Schedule of Energy Commodity Derivative Volumes (Details) MWh in Thousands, MMBTU in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023 MMBTU MWh	Dec. 31, 2022 MMBTU MWh
Purchase [Member] | Physical [Member] | Electric Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
Year one | MWh	5	5
Year two | MWh	0	0
Year three | MWh	0	0
Year four | MWh	0
Purchase [Member] | Physical [Member] | Gas Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
Year one | MMBTU	18,192	19,140
Year two | MMBTU	10,560	533
Year three | MMBTU	3,710	450
Year four | MMBTU	450
Purchase [Member] | Financial [Member] | Electric Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
Year one | MWh	42	0
Year two | MWh	0	0
Year three | MWh	0	0
Year four | MWh	0
Purchase [Member] | Financial [Member] | Gas Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
Year one | MMBTU	56,775	79,253
Year two | MMBTU	54,983	30,658
Year three | MMBTU	12,305	4,895
Year four | MMBTU	1,350
Sales [Member] | Physical [Member] | Electric Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
Year one | MWh	129	136
Year two | MWh	31	0
Year three | MWh	0	0
Year four | MWh	0
Sales [Member] | Physical [Member] | Gas Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
Year one | MMBTU	577	4,145
Year two | MMBTU	1,370	1,370
Year three | MMBTU	1,115	1,115
Year four | MMBTU	0
Sales [Member] | Financial [Member] | Electric Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
Year one | MWh	661	1,011
Year two | MWh	400	0
Year three | MWh	96	0
Year four | MWh	0
Sales [Member] | Financial [Member] | Gas Derivative [Member]
Energy Commodity Derivative Volumes [Line Items]
Year one | MMBTU	10,740	29,473
Year two | MMBTU	10,358	9,668
Year three | MMBTU	1,125	1,125
Year four | MMBTU	0

Derivatives and Risk Manageme_4

Derivatives and Risk Management - Additional Information (Details)	6 Months Ended	12 Months Ended
	Jun. 30, 2023 USD ($) MWh MMBTU	Dec. 31, 2022 USD ($) MMBTU MWh
Canadian [Member]
Derivative [Line Items]
Number of days Canadian currency prices are settled with U.S. dollars	60 days
Interest Rate Swap [Member]
Derivative [Line Items]
Cash collateral posted | $	$ 0	$ 0
Letters of credit outstanding | $	$ 0	$ 0
Purchase [Member] | Physical [Member] | Electric Derivative [Member]
Derivative [Line Items]
Expected deliveries of energy commodity derivatives after four years | MWh	0
Expected deliveries of energy commodity derivatives after three years | MWh		0
Purchase [Member] | Physical [Member] | Gas Derivative [Member]
Derivative [Line Items]
Expected deliveries of energy commodity derivatives after four years | MMBTU	0
Expected deliveries of energy commodity derivatives after three years | MMBTU		0
Purchase [Member] | Financial [Member] | Electric Derivative [Member]
Derivative [Line Items]
Expected deliveries of energy commodity derivatives after four years | MWh	0
Expected deliveries of energy commodity derivatives after three years | MWh		0
Purchase [Member] | Financial [Member] | Gas Derivative [Member]
Derivative [Line Items]
Expected deliveries of energy commodity derivatives after four years | MMBTU	0
Expected deliveries of energy commodity derivatives after three years | MMBTU		0
Sales [Member] | Physical [Member] | Electric Derivative [Member]
Derivative [Line Items]
Expected deliveries of energy commodity derivatives after four years | MWh	0
Expected deliveries of energy commodity derivatives after three years | MWh		0
Sales [Member] | Physical [Member] | Gas Derivative [Member]
Derivative [Line Items]
Expected deliveries of energy commodity derivatives after four years | MMBTU	0
Expected deliveries of energy commodity derivatives after three years | MMBTU		0
Sales [Member] | Financial [Member] | Electric Derivative [Member]
Derivative [Line Items]
Expected deliveries of energy commodity derivatives after four years | MWh	0
Expected deliveries of energy commodity derivatives after three years | MWh		0
Sales [Member] | Financial [Member] | Gas Derivative [Member]
Derivative [Line Items]
Expected deliveries of energy commodity derivatives after four years | MMBTU	0
Expected deliveries of energy commodity derivatives after three years | MMBTU		0

Derivatives and Risk Manageme_5

Derivatives and Risk Management - Summary of Foreign Currency Exchange Derivatives (Details) $ in Thousands, $ in Thousands	Jun. 30, 2023 USD ($) DerivativeContracts	Jun. 30, 2023 CAD ($) DerivativeContracts	Dec. 31, 2022 USD ($) DerivativeContracts	Dec. 31, 2022 CAD ($) DerivativeContracts
Foreign Currency Fair Value Hedge Derivative [Line Items]
Number of contracts | DerivativeContracts	17	17	19	19
United States of America, Dollars [Member] | Foreign Exchange Contract [Member]
Foreign Currency Fair Value Hedge Derivative [Line Items]
Notional amount	$ 8,479		$ 8,563
Canada, Dollars [Member] | Foreign Exchange Contract [Member]
Foreign Currency Fair Value Hedge Derivative [Line Items]
Notional amount		$ 11,255		$ 11,659

Derivatives and Risk Manageme_6

Derivatives and Risk Management - Summary of Unsettled Interest Rate Swap Derivatives (Details) - Interest Rate Swap [Member] $ in Thousands	6 Months Ended	12 Months Ended
	Jun. 30, 2023 USD ($) Contract	Dec. 31, 2022 USD ($) Contract
2023 [Member]
Derivatives, Fair Value [Line Items]
Number of Contracts | Contract		4
Notional Amount | $		$ 40,000
Mandatory Cash Settlement Date		2023
2024 [Member]
Derivatives, Fair Value [Line Items]
Number of Contracts | Contract	2	1
Notional Amount | $	$ 20,000	$ 10,000
Mandatory Cash Settlement Date	2024	2024

Derivatives and Risk Manageme_7

Derivatives and Risk Management - Schedules of Fair Values and Locations of Derivative Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Derivatives, Fair Value [Line Items]
Gross Asset	$ 36,184	$ 157,747
Gross Liability	(92,853)	(276,846)
Collateral Netted	45,209	105,439
Net Asset (Liability) on Balance Sheet	(11,460)	(13,660)
Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Collateral Netted	45,209	105,439
Other Current Liabilities [Member] | Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Gross Liability		(3)
Net Asset (Liability) on Balance Sheet		(3)
Other Current Liabilities [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Gross Liability		(52)
Net Asset (Liability) on Balance Sheet		(52)
Other Current Liabilities [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Gross Asset	27,571	107,902
Gross Liability	(68,874)	(229,607)
Collateral Netted	32,718	94,850
Net Asset (Liability) on Balance Sheet	(8,585)	(26,855)
Other Current Assets [Member] | Foreign Exchange Contract [Member]
Derivatives, Fair Value [Line Items]
Gross Asset	16	43
Net Asset (Liability) on Balance Sheet	16	43
Other Current Assets [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Gross Asset		8,536
Net Asset (Liability) on Balance Sheet		8,536
Other Current Assets [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Gross Asset	715	32,257
Gross Liability	(610)	(22,638)
Net Asset (Liability) on Balance Sheet	105	9,619
Other Property and Investments Net and Other Non-current Assets [Member] | Interest Rate Swap [Member]
Derivatives, Fair Value [Line Items]
Gross Asset	2,883	2,648
Net Asset (Liability) on Balance Sheet	2,883	2,648
Other Property and Investments Net and Other Non-current Assets [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Gross Asset	447	312
Gross Liability	(282)	(16)
Net Asset (Liability) on Balance Sheet	165	296
Other Noncurrent Liabilities [Member] | Commodity Contracts [Member]
Derivatives, Fair Value [Line Items]
Gross Asset	4,552	6,049
Gross Liability	(23,087)	(24,530)
Collateral Netted	12,491	10,589
Net Asset (Liability) on Balance Sheet	$ (6,044)	$ (7,892)

Derivatives and Risk Manageme_8

Derivatives and Risk Management - Schedule of Collateral Outstanding Related to Derivative Instruments (Details) - USD ($)	Jun. 30, 2023	Dec. 31, 2022
Derivative [Line Items]
Balance sheet offsetting	$ 45,209,000	$ 105,439,000
Commodity Contracts [Member]
Derivative [Line Items]
Cash collateral posted	54,978,000	171,581,000
Letters of credit outstanding	16,000,000	49,425,000
Balance sheet offsetting	45,209,000	105,439,000
Interest Rate Swap [Member]
Derivative [Line Items]
Cash collateral posted	0	0
Letters of credit outstanding	0	0
Liabilities with credit-risk-related contingent features	0	52,000
Additional collateral to post	$ 0	$ 52,000

Pension Plans and Other Postr_3

Pension Plans and Other Postretirement Benefit Plans - Additional Information (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
Defined Benefit Plan Disclosure [Line Items]
Payment for pension benefits	$ 6,666	$ 28,000
Percentage of service related net periodic benefit costs capitalized to utility property	40%
Percentage of service related net periodic benefit costs recorded to operating expenses	60%
Percentage of non-service related net periodic benefit costs capitalized to regulatory assets	40%
Percentage of non-service related net periodic benefit costs recorded to other expense	60%
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Expected contributions to pension plan	$ 10,000

Pension Plans and Other Postr_4

Pension Plans and Other Postretirement Benefit Plans - Components of Net Periodic Benefit Costs (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 3,100	$ 6,229	$ 7,994	$ 12,000
Interest cost	8,521	6,520	15,753	13,427
Expected return on plan assets	(10,922)	(10,950)	(21,844)	(21,901)
Amortization of prior service cost	123	75	246	150
Net loss recognition	1,185	939	2,024	2,087
Net periodic benefit cost	2,007	2,813	4,173	5,763
Other Postretirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	532	1,097	1,350	2,160
Interest cost	1,909	1,384	2,953	2,824
Expected return on plan assets	(891)	(700)	(1,782)	(1,400)
Amortization of prior service cost	(263)	(275)	(526)	(550)
Net loss recognition	(8)	870	525	1,760
Net periodic benefit cost	$ 1,279	$ 2,376	$ 2,520	$ 4,794

Income Taxes - Summary of Signi

Income Taxes - Summary of Significant Factors Impact on Difference Between Effective Tax Rate and Federal Statutory Rate (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Income Tax Disclosure [Abstract]
Federal income taxes at statutory rates	$ 2,452	$ 2,195	$ 12,577	$ 14,948
Flow through related to deduction of meters and mixed service costs	(5,689)	(2,401)	(19,212)	(19,835)
Tax effect of regulatory treatment of utility plant differences	(1,525)	(976)	(5,212)	(7,298)
State income tax expense	232	78	798	901
Tax credits	(1,135)		(1,135)
Other	(145)	105	(254)	(551)
Total income tax benefit	$ (5,810)	$ (999)	$ (12,438)	$ (11,835)
Federal income taxes at statutory rates	21%	21%	21%	21%
Flow through related to deduction of meters and mixed service costs	(48.70%)	(23.00%)	(32.10%)	(27.90%)
Tax effect of regulatory treatment of utility plant differences	(13.10%)	(9.30%)	(8.70%)	(10.30%)
State income tax expense	2%	0.70%	1.30%	1.30%
Tax credits	(9.70%)		(1.90%)
Other	(1.30%)	1%	(0.40%)	(0.70%)
Total income tax benefit	(49.80%)	(9.60%)	(20.80%)	(16.60%)

Short-Term Borrowings - Additio

Short-Term Borrowings - Additional Information (Details) - USD ($)	1 Months Ended	6 Months Ended	12 Months Ended
	Jun. 30, 2021	Jun. 30, 2023	Dec. 31, 2022	Mar. 31, 2023	Apr. 30, 2014
Short-term Debt [Line Items]
Line of credit, outstanding			$ 0
Avista Utilities [Member]
Short-term Debt [Line Items]
Line of credit facility, maximum borrowing capacity		$ 500,000,000			$ 400,000,000
Line of credit facility, expiration date	2028-06
Line of credit facility additional expiration period		2 years
Bearing interest rate		12%
Credit agreement amount borrowed				$ 150,000,000
Letters of credit outstanding		$ 4,638,000	35,563,000
Line of credit facility, covenant terms, maximum debt to equity ratio		65%
Avista Utilities [Member] | Revolving credit agreement [Member]
Short-term Debt [Line Items]
Line of credit facility, termination date		2023-06
Current borrowings			100,000,000
Avista Utilities [Member] | 2022 Term Loan [Member]
Short-term Debt [Line Items]
Principal amount			$ 150,000,000
Maturity date			Mar. 30, 2023
Avista Utilities [Member] | Letter of Credit [Member]
Short-term Debt [Line Items]
Principal amount			$ 50,000,000
Letters of credit outstanding		$ 16,000,000	18,500,000
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	$ 0

Short-Term Borrowings - Schedul

Short-Term Borrowings - Schedule of Balances Outstanding and Interest Rates of Borrowings (Details) - Avista Utilities [Member] - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Short-term Debt [Line Items]
Borrowings outstanding at end of period	$ 203,000	$ 313,000
Letters of credit outstanding at end of period	$ 4,638	$ 35,563
Average interest rate on borrowings at end of period	6.24%	5.31%

Long-Term Debt - Additional Inf

Long-Term Debt - Additional Information (Details) $ in Thousands	1 Months Ended	6 Months Ended
	Mar. 31, 2023 USD ($) Contract	Jun. 30, 2023 USD ($)	Jun. 30, 2022 USD ($)
Debt Instrument [Line Items]
Proceeds from issuance of long-term debt		$ 250,000	$ 399,856
Repayments of short-term debt		$ 150,000
5.66% Due in 2053 [Member] | First Mortgage [Member]
Debt Instrument [Line Items]
Proceeds from issuance of long-term debt	$ 250,000
Debt instrument interest rate percentage	5.66%
Debt instrument maturity year	2053
5.66% Due in 2053 [Member] | Interest Rate Swap [Member] | First Mortgage [Member]
Debt Instrument [Line Items]
Number of interest rate swaps settled | Contract	4
Notional amount	$ 40,000
Net payments from settlement of derivatives	$ 7,500

Long-Term Debt to Affiliated _3

Long-Term Debt to Affiliated Trusts - Additional Information (Details) - USD ($) $ in Millions	1 Months Ended	6 Months Ended	12 Months Ended
	Jul. 31, 2023	Jun. 30, 2023	Dec. 31, 2000
Debt Instrument [Line Items]
Payments for repurchase of trust preferred securities			$ 10
1997 Floating Rate Junior Subordinated Deferrable Interest Debentures, Series B [Member] | Avista Capital II [Member]
Debt Instrument [Line Items]
Junior subordinated debenture issuance date		1997
Principal amount		$ 51.5
Avista Corp [Member]
Debt Instrument [Line Items]
Noncontrolling interest, ownership percentage by parent		100%
Trust Preferred Securities Subject to Mandatory Redemption [Member] | 1997 Floating Rate Junior Subordinated Deferrable Interest Debentures, Series B [Member] | Avista Capital II [Member]
Debt Instrument [Line Items]
Principal amount		$ 50
Debt instrument, description of variable rate basis		LIBOR
Debt instrument, basis spread on variable rate		0.875%
Trust Preferred Securities Subject to Mandatory Redemption [Member] | 1997 Floating Rate Junior Subordinated Deferrable Interest Debentures, Series B [Member] | SOFR [Member] | Avista Capital II [Member] | Forecast [Member]
Debt Instrument [Line Items]
Debt instrument, basis spread on variable rate	1.137%
Debt instrument basis tenor spread adjustment rate	0.26%
Common Trust Securities [Member] | 1997 Floating Rate Junior Subordinated Deferrable Interest Debentures, Series B [Member] | Avista Capital II [Member]
Debt Instrument [Line Items]
Principal amount		$ 1.5

Long-Term Debt to Affiliated _4

Long-Term Debt to Affiliated Trusts - Schedule of Distribution Rates Paid (Details) - Trust Preferred Securities Subject to Mandatory Redemption [Member]	Jun. 30, 2023	Dec. 31, 2022
Debt Instrument [Line Items]
Interest rate	6.37%	5.64%
Minimum [Member]
Debt Instrument [Line Items]
Interest rate	5.64%	1.05%
Maximum [Member]
Debt Instrument [Line Items]
Interest rate	6.37%	5.64%

Fair Value - Schedule of Carryi

Fair Value - Schedule of Carrying Value and Estimated Fair Value of Financial Instruments (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Level 2 [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	$ 1,107,000	$ 1,113,500
Level 2 [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	975,122	966,881
Level 3 [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	1,450,000	1,200,000
Level 3 [Member] | Reported Value Measurement [Member] | Alaska Electric Light & Power [Member] | Finance Lease [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Finance Lease Obligation	44,113	45,730
Level 3 [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	1,137,437	881,480
Level 3 [Member] | Estimate of Fair Value Measurement [Member] | Alaska Electric Light & Power [Member] | Finance Lease [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Finance Lease Obligation	40,500	41,700
Affiliated Entity [Member] | Level 3 [Member] | Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	51,547	51,547
Affiliated Entity [Member] | Level 3 [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term Debt, Fair Value	$ 42,284	$ 42,836

Fair Value - Additional Informa

Fair Value - Additional Information (Details)	Jun. 30, 2023 Investment
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Number of equity investments measured at fair value on recurring basic	2
Measurement Input, Quoted Price [Member] | Secured and Unsecured Debt [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, measurement input	1
Measurement Input, Quoted Price [Member] | Minimum [Member] | Secured and Unsecured Debt [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, measurement input	0.6096
Measurement Input, Quoted Price [Member] | Maximum [Member] | Secured and Unsecured Debt [Member] | Estimate of Fair Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Long-term debt, measurement input	1.0685

Fair Value - Schedule of Fair V

Fair Value - Schedule of Fair Value of Assets and Liabilities Measured on Recurring Basis (Details) - USD ($) $ in Thousands		Jun. 30, 2023	Dec. 31, 2022
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset		$ 36,184	$ 157,747
Liability		92,853	276,846
Fair Value, Recurring [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, Fair Value Disclosure		58,904	82,825
Financial Liabilities Fair Value Disclosure		14,629	34,802
Counterparty and Cash Collateral Netting, Assets	[1]	(33,015)	(136,605)
Counterparty and Cash Collateral Netting, Liabilities	[1]	(78,224)	(242,044)
Fair Value, Recurring [Member] | Fixed Income Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deferred compensation assets:	[2]	1,142	1,267
Fair Value, Recurring [Member] | Equity Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity investments		48,453	54,284
Deferred compensation assets:	[2]	6,140	6,132
Fair Value, Recurring [Member] | Energy Commodity Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Counterparty and Cash Collateral Netting, Assets	[1]	(33,015)	(136,605)	[3]
Derivative Asset		270	9,915	[3]
Counterparty and Cash Collateral Netting, Liabilities	[1],[3]	(78,224)	(242,044)
Derivative Liability	[3]	14,629	34,747
Fair Value, Recurring [Member] | Interest Rate Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset		2,883	11,184
Derivative Liability			$ 52
Fair Value, Recurring [Member] | Natural Gas Exchange Agreements [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Liability		$ 11,721
Fair Value, Recurring [Member] | Foreign Exchange Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Derivative Asset, Statement of Financial Position [Extensible Enumeration]		Investments and Other Noncurrent Assets	Investments and Other Noncurrent Assets
Derivative Liability, Statement of Financial Position [Extensible Enumeration]			Other Liabilities, Noncurrent
Derivative Asset		$ 16	$ 43
Derivative Liability			3
Fair Value, Recurring [Member] | Level 1 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, Fair Value Disclosure		7,282	7,399
Fair Value, Recurring [Member] | Level 1 [Member] | Fixed Income Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deferred compensation assets:	[2]	1,142	1,267
Fair Value, Recurring [Member] | Level 1 [Member] | Equity Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Deferred compensation assets:	[2]	6,140	6,132
Fair Value, Recurring [Member] | Level 2 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, Fair Value Disclosure		36,184	157,459
Financial Liabilities Fair Value Disclosure		81,132	258,824
Fair Value, Recurring [Member] | Level 2 [Member] | Energy Commodity Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset		33,285	146,232	[3]
Liability	[3]	81,132	258,769
Fair Value, Recurring [Member] | Level 2 [Member] | Interest Rate Swap [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset		2,883	11,184
Liability			52
Fair Value, Recurring [Member] | Level 2 [Member] | Foreign Exchange Contract [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset		16	43
Liability			3
Fair Value, Recurring [Member] | Level 3 [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Assets, Fair Value Disclosure		48,453	54,572
Financial Liabilities Fair Value Disclosure		11,721	18,022
Fair Value, Recurring [Member] | Level 3 [Member] | Equity Funds [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Equity investments		48,453	54,284
Fair Value, Recurring [Member] | Level 3 [Member] | Energy Commodity Derivatives [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Gross Asset	[3]		288
Liability	[3]	$ 11,721	$ 18,022
[1] The Company is permitted to net derivative assets and derivative liabilities with the same counterparty when a legally enforceable master netting agreement exists. In addition, the Company nets derivative assets and derivative liabilities against any payables and receivables for cash collateral held or placed with these same counterparties. Included in other property and investments-net and other non-current assets on the Condensed Consolidated Balance Sheets. The Level 3 energy commodity derivative balances are associated with natural gas exchange agreements.

Fair Value - Schedule of Quanti

Fair Value - Schedule of Quantitative Information (Details) $ in Thousands	6 Months Ended
	Jun. 30, 2023 USD ($) MMBTU $ / MMBTU	Dec. 31, 2022 USD ($)
Fair Value, Recurring [Member] | Equity Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Equity investments	$ 48,453	$ 54,284
Fair Value, Recurring [Member] | Equity Investments [Member] | Level 3 [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Equity investments	$ 48,453	$ 54,284
Fair Value, Recurring [Member] | Discounted Cash Flows [Member] | Equity Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Equity investments, terminal date	2026
Fair Value, Recurring [Member] | Discounted Cash Flows [Member] | Equity Investments [Member] | Discount Rate [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Equity investments, measurement input	25
Fair Value, Recurring [Member] | Discounted Cash Flows [Member] | Equity Investments [Member] | Market Exit Reduction [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Equity investments, measurement input	50
Fair Value, Recurring [Member] | Minimum [Member] | Market Approach [Member] | Equity Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Equity investments, comparable enterprise values	$ 130,000
Equity investments, time to liquidity event	0 years
Equity Investments, probability weighting	25%
Fair Value, Recurring [Member] | Minimum [Member] | Discounted Cash Flows [Member] | Equity Investments [Member] | Annual Revenues [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Equity investments, annual revenues	$ 14,000
Fair Value, Recurring [Member] | Minimum [Member] | Discounted Cash Flows [Member] | Equity Investments [Member] | Revenue Market Multiples [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Equity investments, measurement input	1.39
Fair Value, Recurring [Member] | Maximum [Member] | Market Approach [Member] | Equity Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Equity investments, comparable enterprise values	$ 388,600
Equity investments, time to liquidity event	2 years
Equity Investments, probability weighting	75%
Fair Value, Recurring [Member] | Maximum [Member] | Discounted Cash Flows [Member] | Equity Investments [Member] | Annual Revenues [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Equity investments, annual revenues	$ 265,000
Fair Value, Recurring [Member] | Maximum [Member] | Discounted Cash Flows [Member] | Equity Investments [Member] | Revenue Market Multiples [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Equity investments, measurement input	7.1
Fair Value, Recurring [Member] | Weighted Average [Member] | Market Approach [Member] | Equity Investments [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Equity investments, comparable enterprise values	$ 246,000
Fair Value, Recurring [Member] | Weighted Average [Member] | Discounted Cash Flows [Member] | Equity Investments [Member] | Revenue Market Multiples [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Equity investments, measurement input	3.39
Natural Gas Exchange Agreements [Member] | Purchase [Member] | Minimum [Member] | Internally Derived Weighted Average Cost Of Gas [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Derivative, Forward Price | $ / MMBTU	2.53
Transaction/Delivery Volumes | MMBTU	140,000
Natural Gas Exchange Agreements [Member] | Purchase [Member] | Maximum [Member] | Internally Derived Weighted Average Cost Of Gas [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Derivative, Forward Price | $ / MMBTU	3.39
Transaction/Delivery Volumes | MMBTU	310,000
Natural Gas Exchange Agreements [Member] | Purchase [Member] | Weighted Average [Member] | Internally Derived Weighted Average Cost Of Gas [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Derivative, Forward Price | $ / MMBTU	2.99
Natural Gas Exchange Agreements [Member] | Sales [Member] | Minimum [Member] | Internally Derived Weighted Average Cost Of Gas [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Derivative, Forward Price | $ / MMBTU	2.92
Transaction/Delivery Volumes | MMBTU	75,000
Natural Gas Exchange Agreements [Member] | Sales [Member] | Maximum [Member] | Internally Derived Weighted Average Cost Of Gas [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Derivative, Forward Price | $ / MMBTU	9.53
Transaction/Delivery Volumes | MMBTU	310,000
Natural Gas Exchange Agreements [Member] | Sales [Member] | Weighted Average [Member] | Internally Derived Weighted Average Cost Of Gas [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Derivative, Forward Price | $ / MMBTU	6.79
Natural Gas Exchange Agreements [Member] | Fair Value, Recurring [Member]
Fair Value Assets And Liabilities Measured On Recurring And Nonrecurring Basis Valuation Techniques [Line Items]
Derivative Liability	$ (11,721)

Fair Value - Schedule of Activi

Fair Value - Schedule of Activity For Energy Commodity Derivative Assets (Liabilities) Measured At Fair Value Using Significant Unobservable Inputs (Level 3) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Fair Value Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other Nonoperating Income (Expense)		Other Nonoperating Income (Expense)
Level 3 [Member]
Fair Value Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 39,952	$ (6,197)	$ 36,550	$ (7,771)
Included in regulatory assets/liabilities	(1,016)	5,196	5,767	7,695
Recognized in net income	(2,561)		(5,198)
Purchases			2,367
Settlements	357	(1,288)	246	(2,213)
Other			(3,000)
Ending Balance	36,732	(2,289)	36,732	(2,289)
Natural Gas Exchange Agreements [Member] | Level 3 [Member]
Fair Value Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	(11,062)	(6,197)	(17,734)	(7,771)
Included in regulatory assets/liabilities	(1,016)	5,196	5,767	7,695
Settlements	357	(1,288)	246	(2,213)
Ending Balance	(11,721)	$ (2,289)	(11,721)	$ (2,289)
Equity Investment [Member] | Level 3 [Member]
Fair Value Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	51,014		54,284
Recognized in net income	(2,561)		(5,198)
Purchases and debt conversions			2,367
Other			(3,000)
Ending Balance	$ 48,453		$ 48,453

Common Stock - Additional Infor

Common Stock - Additional Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Class Of Stock [Line Items]
Proceeds from issuance of common stock	$ 29,600		$ 59,525	$ 60,765
Common stock, shares authorized	200,000,000		200,000,000		200,000,000
Common Stock [Member]
Class Of Stock [Line Items]
Shares issued under sales agency agreements	761,586	537,635	1,578,236	1,478,559
Sales Agency Agreement [Member] | Common Stock [Member]
Class Of Stock [Line Items]
Shares issued under sales agency agreements	800,000		1,500,000

Accumulated Other Comprehensi_3

Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Loss, Net of Tax (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Accumulated Other Comprehensive Loss [Abstract]
Unfunded benefit obligation for pensions and other postretirement benefit plans - net of taxes of $557 and $547, respectively	$ 2,095	$ 2,058

Accumulated Other Comprehensi_4

Accumulated Other Comprehensive Loss - Schedule of Accumulated Other Comprehensive Loss, Net of Tax (Parenthetical) (Details) - USD ($) $ in Thousands	Jun. 30, 2023	Dec. 31, 2022
Accumulated Other Comprehensive Loss [Abstract]
Accumulated other comprehensive income (loss), pension and other postretirement benefit plans net unamortized (gain) loss, tax	$ 557	$ 547

Accumulated Other Comprehensi_5

Accumulated Other Comprehensive Loss - Reclassification out of Accumulated Other Comprehensive Loss (Details) - Accumulated Defined Benefit Plans Adjustment Attributable to Parent [Member] - Reclassification out of Accumulated Other Comprehensive Income [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Amortization of net prior service cost	$ (140)	$ (200)	$ (280)	$ (400)
Amortization of net loss	1,177	1,809	2,549	3,847
Adjustment due to effects of regulation	(1,061)	(1,263)	(2,316)	(2,752)
Other comprehensive (income) loss, defined benefit plan, reclassification adjustment from AOCI, before tax	(24)	346	(47)	695
Other comprehensive (income) loss, defined benefit plan, reclassification adjustment from AOCI, tax	5	(73)	10	(146)
Other comprehensive (income) loss, defined benefit plan, reclassification adjustment from AOCI, after tax	$ (19)	$ 273	$ (37)	$ 549

Earnings Per Common Share - Sch

Earnings Per Common Share - Schedule of Computation of Basic and Diluted Earnings Per Common Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Numerator:
Net income	$ 17,484	$ 11,453	$ 72,329	$ 83,018
Denominator:
Weighted-average number of common shares outstanding-basic	75,983	72,624	75,576	72,205
Effect of dilutive securities:
Performance and restricted stock awards	148	34	127	89
Weighted-average number of common shares outstanding-diluted	76,131	72,658	75,703	72,294
Earnings per common share:
Basic	$ 0.23	$ 0.16	$ 0.96	$ 1.15
Diluted	$ 0.23	$ 0.16	$ 0.96	$ 1.15

Earnings Per Common Share - Add

Earnings Per Common Share - Additional Information (Details) - shares	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
Earnings Per Share [Abstract]
Antidilutive securities excluded from computation of earnings per share, amount	0	0	0	0

Commitments and Contingencies -

Commitments and Contingencies - Additional Information (Details)	1 Months Ended				6 Months Ended
	Apr. 30, 2022 USD ($) a	Jul. 31, 2021 USD ($)	Sep. 30, 2020 a	Aug. 31, 2019 USD ($)	Jun. 30, 2023 Lawsuit Plaintiff	Sep. 30, 2022	May 31, 2021 a Building	Sep. 02, 2020 a Building
Washington [Member]
Loss Contingencies [Line Items]
Wildfires covered area which damaged several residential structures, (in acres) | a			5
Natural and Cultural Damage Claim [Member]
Loss Contingencies [Line Items]
Litigation settlement damages claim amount | $		$ 2,000,000
Boyds Fire [Member] | Damage from Fire [Member] | Maximum [Member]
Loss Contingencies [Line Items]
Loss contingency, damages sought, value | $				$ 4,400,000
Labor Day Windstorm [Member] | Damage from Fire [Member]
Loss Contingencies [Line Items]
Number of residential, commercial and other structures impacted | Building								230
Road fire covered area | a								25,000
Road 11 Fire [Member] | Damage from Fire [Member] | Avista Corp [Member]
Loss Contingencies [Line Items]
Loss contingency, damages sought, value | $	$ 5,000,000
Road fire covered area | a	10,000
Babb Road Fire [Member] | Damage from Fire [Member]
Loss Contingencies [Line Items]
Number of residential, commercial and other structures impacted | Building							220
Road fire covered area | a							15,000
Number of lawsuits filed seeking unspecified damages | Lawsuit					9
Number of subrogation actions filed | Lawsuit					6
Number of actions on behalf of individual plaintiffs | Plaintiff					2
Number of class action lawsuit | Lawsuit					1
System Unit Resource Protection Act [Member] | Natural and Cultural Damage Claim [Member]
Loss Contingencies [Line Items]
Increased potential claim | $		$ 6,000,000
Colstrip [Member]
Loss Contingencies [Line Items]
Agreement voting requirement					NorthWestern has initiated arbitration pursuant to the O&O Agreement to resolve these business disagreements, and two actions have been initiated to compel arbitration of those disputes: one by Talen in the Montana Thirteenth Judicial District Court for Yellowstone County, and one by the Western Co-Owners, which is pending in Montana Federal District Court. In light of the ownership transfer agreements discussed below, the Colstrip owners agreed to stay both the litigation and the arbitration through September 29, 2023, at which time the proceedings would resume absent further agreement between the owners.
Colstrip [Member] | PSE [Member] | Unit 4 [Member]
Loss Contingencies [Line Items]
Owners percentage interest					25%	25%

Commitments and Contingencies_2

Commitments and Contingencies - Ownership and Operating Interest Percentage (Details) - Colstrip [Member]	Jun. 30, 2023	Jan. 16, 2023	Sep. 30, 2022
Avista [Member] | Unit 3 [Member]
Loss Contingencies [Line Items]
Owners percentage interest	15%
Avista [Member] | Unit 4 [Member]
Loss Contingencies [Line Items]
Owners percentage interest	15%
PacifiCorp [Member] | Unit 3 [Member]
Loss Contingencies [Line Items]
Owners percentage interest	10%
PacifiCorp [Member] | Unit 4 [Member]
Loss Contingencies [Line Items]
Owners percentage interest	10%
PGE [Member] | Unit 3 [Member]
Loss Contingencies [Line Items]
Owners percentage interest	20%
PGE [Member] | Unit 4 [Member]
Loss Contingencies [Line Items]
Owners percentage interest	20%
PSE [Member] | Unit 3 [Member]
Loss Contingencies [Line Items]
Owners percentage interest	25%
PSE [Member] | Unit 4 [Member]
Loss Contingencies [Line Items]
Owners percentage interest	25%		25%
NorthWestern [Member] | Unit 4 [Member]
Loss Contingencies [Line Items]
Owners percentage interest	30%	15%
Talen [Member] | Unit 3 [Member]
Loss Contingencies [Line Items]
Owners percentage interest	30%

Information by Business Segme_3

Information by Business Segments - Additional Information (Details)	6 Months Ended
	Jun. 30, 2023 ReportableSegments
Segment Reporting [Abstract]
Number of reportable segments	1

Information by Business Segme_4

Information by Business Segments - Schedule of Business Segments (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Segment Reporting Information [Line Items]
Operating revenues	$ 379,937	$ 378,566	$ 854,568	$ 840,612
Resource costs	141,244	157,397	334,172	344,265
Other operating expenses	103,820	107,392	209,809	202,875
Depreciation and amortization	66,148	62,836	131,367	125,445
Income (loss) from operations	43,808	24,283	120,409	107,252
Interest expense	35,626	28,695	71,281	56,879
Income taxes	(5,810)	(999)	(12,438)	(11,835)
Net income (loss)	17,484	11,453	72,329	83,018
Capital expenditures	126,256	115,001	226,749	211,402
Total Assets	7,371,315		7,371,315		$ 7,417,350
Avista Utilities [Member]
Segment Reporting Information [Line Items]
Operating revenues	368,604	368,515	828,746	817,387
Alaska Electric Light & Power [Member]
Segment Reporting Information [Line Items]
Operating revenues	11,194	9,906	25,557	22,960
Operating Segments [Member] | Utility Revenue [Member]
Segment Reporting Information [Line Items]
Operating revenues	379,798	378,421	854,303	840,347
Resource costs	141,244	157,397	334,172	344,265
Other operating expenses	103,071	104,482	208,049	199,009
Depreciation and amortization	66,148	62,806	131,336	125,383
Income (loss) from operations	44,418	27,078	121,935	110,915
Interest expense	35,496	28,565	71,022	56,624
Income taxes	(5,083)	(2,776)	(11,492)	(13,876)
Net income (loss)	20,169	4,721	75,838	75,292
Capital expenditures	126,256	114,659	226,746	210,646
Total Assets	7,200,385		7,200,385		7,240,486
Operating Segments [Member] | Avista Utilities [Member]
Segment Reporting Information [Line Items]
Capital expenditures				207,314
Operating Segments [Member] | Avista Utilities [Member] | Utility Revenue [Member]
Segment Reporting Information [Line Items]
Operating revenues	368,604	368,515	828,746	817,387
Resource costs	140,017	156,221	332,154	342,645
Other operating expenses	99,276	100,782	200,665	191,766
Depreciation and amortization	63,419	60,106	125,883	119,985
Income (loss) from operations	41,257	25,037	111,816	102,816
Interest expense	34,044	27,078	68,118	53,650
Income taxes	(5,556)	(2,565)	(13,504)	(14,925)
Net income (loss)	18,810	3,950	70,437	71,228
Capital expenditures	121,834	111,850	219,598
Total Assets	6,929,611		6,929,611		6,976,164
Operating Segments [Member] | Alaska Electric Light & Power [Member] | Utility Revenue [Member]
Segment Reporting Information [Line Items]
Operating revenues	11,194	9,906	25,557	22,960
Resource costs	1,227	1,176	2,018	1,620
Other operating expenses	3,795	3,700	7,384	7,243
Depreciation and amortization	2,729	2,700	5,453	5,398
Income (loss) from operations	3,161	2,041	10,119	8,099
Interest expense	1,452	1,487	2,904	2,974
Income taxes	473	(211)	2,012	1,049
Net income (loss)	1,359	771	5,401	4,064
Capital expenditures	4,422	2,809	7,148	3,332
Total Assets	270,774		270,774		264,322
Other [Member] | Non-Utility Revenue [Member]
Segment Reporting Information [Line Items]
Operating revenues	139	145	265	265
Resource costs	0	0	0	0
Other operating expenses	749	2,910	1,760	3,866
Depreciation and amortization	0	30	31	62
Income (loss) from operations	(610)	(2,795)	(1,526)	(3,663)
Interest expense	448	137	795	265
Income taxes	(727)	1,777	(946)	2,041
Net income (loss)	(2,685)	6,732	(3,509)	7,726
Capital expenditures	0	342	3	756
Total Assets	189,314		189,314		187,027
Intersegment Eliminations [Member]
Segment Reporting Information [Line Items]
Operating revenues	0	0	0	0
Resource costs	0	0	0	0
Other operating expenses	0	0	0	0
Depreciation and amortization	0	0	0	0
Income (loss) from operations	0	0	0	0
Interest expense	(318)	(7)	(536)	(10)
Income taxes	0	0	0	0
Net income (loss)	0	0	0	0
Capital expenditures	0	$ 0	0	$ 0
Total Assets	$ (18,384)		$ (18,384)		$ (10,163)