Revenue - Schedule of Utilities Operating Revenue Expense Taxes (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2025	Mar. 31, 2024
Revenue from Contract with Customer [Abstract]
Utility-related taxes	$ 27	$ 27

Public Utility Operating Expenses Excise Taxes Collected and Reported Gross in Revenues and Operating Expenses

No definition available.

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Namespace Prefix:	ava_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration