Agreement voting requirement description.

No definition available.

Name:	ava_AgreementVotingRequirementDescription
Namespace Prefix:	ava_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Litigation settlement increased potential claim

+ References

No definition available.

+ Details

Name:	ava_LitigationSettlementIncreasedPotentialClaim
Namespace Prefix:	ava_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Majority Of Bargaining Unit Employees, Percentage

+ References

No definition available.

+ Details

Name:	ava_MajorityOfBargainingUnitEmployeesPercentage
Namespace Prefix:	ava_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Number of residential, commercial and other structures impacted.

+ References

No definition available.

+ Details

Name:	ava_NumberOfResidentialCommercialAndOtherStructuresImpacted
Namespace Prefix:	ava_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- Definition

Percentage Of Employees, Collective Bargaining Agreement

+ References

No definition available.

+ Details

Name:	ava_PercentageOfEmployeesCollectiveBargainingAgreement
Namespace Prefix:	ava_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of maximum jointly owned utility plant proportionate ownership share.

+ References

No definition available.

+ Details

Name:	ava_PercentageOfMaximumJointlyOwnedUtilityPlantProportionateOwnershipShare
Namespace Prefix:	ava_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Road fire covered area.

+ References

No definition available.

+ Details

Name:	ava_RoadFireCoveredArea
Namespace Prefix:	ava_
Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

Wildfire covered area.

+ References

No definition available.

+ Details

Name:	ava_WildfireCoveredArea
Namespace Prefix:	ava_
Data Type:	dtr-types:areaItemType
Balance Type:	na
Period Type:	instant

- Definition

The proportionate share of interest (percent) in a jointly owned utility plant.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 360
-Section S99
-Paragraph 1
-Subparagraph (SAB Topic 10.C)
-URI http://asc.fasb.org/extlink&oid=122136288&loc=d3e659983-123033

+ Details

Name:	us-gaap_JointlyOwnedUtilityPlantProportionateOwnershipShare
Namespace Prefix:	us-gaap_
Data Type:	dtr-types:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount awarded to other party in judgment or settlement of litigation.

+ References

No definition available.

+ Details

Name:	us-gaap_LitigationSettlementAmountAwardedToOtherParty
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- 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_LossContingenciesLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 9
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14557-108349

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14435-108349

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121557415&loc=d3e14326-108349

+ Details

Name:	us-gaap_LossContingencyDamagesSoughtValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=ava_NaturalAndCulturalDamageClaimMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=ava_BoydsFireMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LossContingenciesByNatureOfContingencyAxis=us-gaap_DamageFromFireExplosionOrOtherHazardMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=ava_LaborDayWindstormMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=ava_BabbRoadFireMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=ava_SystemUnitResourceProtectionActMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_LitigationCaseAxis=ava_ColstripMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=ava_AvistaCorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=ava_AvistaUtilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Commitments and Contingencies - Additional Information (Details)	1 Months Ended		12 Months Ended
	Jul. 31, 2021 USD ($)	Aug. 31, 2019 USD ($)	Dec. 31, 2021	May 14, 2021 a Building	Sep. 02, 2020 a Building
Loss Contingencies [Line Items]
Owners percentage interest			15.00%
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]
Wildfire covered area \| a					22,000
Number of residential, commercial and other structures impacted \| Building					230
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
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			These business disagreements, in turn, have led to disagreements as to the interpretation of the O&O Agreement, including, but not limited to, what percentage voting requirement under the O&O Agreement (55 percent vs. 100 percent) is needed to remove one or more of the Colstrip units from service or to make a determination that the project can no longer be operated consistent with prudent utility practice or the requirements of governmental agencies having jurisdiction.
Avista Corp [Member]
Loss Contingencies [Line Items]
Percentage of maximum ownership			30.00%
Avista Corp [Member] \| Colstrip [Member]
Loss Contingencies [Line Items]
Owners percentage interest			15.00%
Avista Utilities [Member]
Loss Contingencies [Line Items]
Percentage Of Employees, Collective Bargaining Agreement			40.00%
Majority Of Bargaining Unit Employees, Percentage			90.00%