XML 82 R58.htm IDEA: XBRL DOCUMENT
v3.23.3

Pension Plans and Other Postretirement Benefit Plans - Additional Information (Details) - USD ($) | 9 Months Ended
--- | ---
Sep. 30, 2023 | Sep. 30, 2022
Defined Benefit Plan Disclosure [Line Items] |  |
Payment for pension benefits | $ 10,000,000 | $ 42,000,000
Percentage of service related net periodic benefit costs capitalized to utility property | 40.00% |
Percentage of service related net periodic benefit costs recorded to operating expenses | 60.00% |
Percentage of non-service related net periodic benefit costs capitalized to regulatory assets | 40.00% |
Percentage of non-service related net periodic benefit costs recorded to other expense | 60.00% |
Pension Plans, Defined Benefit [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Expected contributions to pension plan | $ 0 |

X
- Definition Percentage of non-service related net periodic benefit costs capitalized to regulatory assets. + References No definition available. + Details
Name: | ava_PercentageOfNonserviceRelatedNetPeriodicBenefitCostsCapitalizedToRegulatoryAssets
Namespace Prefix: | ava_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of non-service related net periodic benefit costs recorded to other expense. + References No definition available. + Details
Name: | ava_PercentageOfNonserviceRelatedNetPeriodicBenefitCostsRecordedToOtherExpense
Namespace Prefix: | ava_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of service related net periodic benefit costs capitalized to utility property. + References No definition available. + Details
Name: | ava_PercentageOfServiceRelatedNetPeriodicBenefitCostsCapitalizedToUtilityProperty
Namespace Prefix: | ava_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of service related net periodic benefit costs recorded to operating expenses. + References No definition available. + Details
Name: | ava_PercentageOfServiceRelatedNetPeriodicBenefitCostsRecordedToOperatingExpenses
Namespace Prefix: | ava_
Data Type: | dtr-types:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of contribution expected to be received by defined benefit plan from employer in remainder of current fiscal year. Excludes contribution previously paid by employer in current fiscal year. + References Reference 1: http://www.xbrl.org/2003/role/exampleRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 55 -Paragraph 18 -Publisher FASB -URI https://asc.fasb.org//1943274/2147480482/715-20-55-18 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Topic 715 -SubTopic 20 -Name Accounting Standards Codification -Section 50 -Paragraph 6 -Subparagraph (b) -Publisher FASB -URI https://asc.fasb.org//1943274/2147480506/715-20-50-6 + Details
Name: | us-gaap_DefinedBenefitPlanExpectedFutureEmployerContributionsRemainderOfFiscalYear
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Amount of cash outflow for pension benefit. Includes, but is not limited to, employer contribution to fund plan asset and payment to retiree. Excludes other postretirement benefit. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Name Accounting Standards Codification -Section 45 -Paragraph 25 -Subparagraph (g) -SubTopic 10 -Topic 230 -Publisher FASB -URI https://asc.fasb.org//1943274/2147482740/230-10-45-25 + Details
Name: | us-gaap_PensionContributions
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- Details
Name: | us-gaap_RetirementPlanTypeAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |