Regulatory Matters - Schedule of Regulatory Assets and Liabilities (Parenthetical) (Details)	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2018	Dec. 31, 2017
Regulated Asset Liability [Line Items]
Federal statutory tax rate	21.00%	21.00%	21.00%	21.00%	35.00%
Avista Utilities [Member]
Regulated Asset Liability [Line Items]
Tax cuts and jobs act period to return plant related excess deferred income taxes	33 years
Alaska Electric Light & Power [Member]
Regulated Asset Liability [Line Items]
Tax cuts and jobs act period to return plant related excess deferred income taxes	22 years