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Pension Plans and Other Postretirement Benefit Plans - Components of Net Periodic Benefit Costs (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2022
Defined Benefit Plan Disclosure [Line Items]
Percentage of service related net periodic benefit costs capitalized to utility property	45.00%
Percentage of service related net periodic benefit costs recorded to operating expenses	55.00%
Pension Plan and SERP [Member]
Defined Benefit Plan Disclosure [Line Items]
Regulatory asset amortization period		12 years

X

- Definition

Percentage of service related net periodic benefit costs capitalized to utility property.

+ References

No definition available.

+ Details

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X

- Definition

Percentage of service related net periodic benefit costs recorded to operating expenses.

+ References

No definition available.

+ Details

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Namespace Prefix:	ava_
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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

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X

- Definition

Amortization period for the recovery of regulatory asset, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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X

- Details

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