Net payments from settlement of derivatives.

No definition available.

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- Definition

Number of Interest Rate Swaps Settled

+ References

No definition available.

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- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

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- 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.

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- Definition

Description of the maturity date of the debt instrument including whether the debt matures serially and, if so, a brief description of the serial maturities.

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- Definition

Nominal or face amount used to calculate payment on derivative.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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- Definition

Noncurrent portion of a debt security issued by a state, certain agencies or authorities, a local government, or development corporation to finance the construction of air- or water-pollution control facilities or sewage or solid waste disposal facilities pursuant to federal law. The bonds are backed by the credit of the beneficiary of the financing rather than the credit of the issuer.

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- Definition

The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.

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Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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Long-Term Debt - Schedule Of Long-Term Debt Instruments (Parenthetical) (Details)	1 Months Ended		12 Months Ended
	Dec. 31, 2021 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($) Contract	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Apr. 30, 2014 USD ($)
Debt Instrument [Line Items]
Secured Debt	$ 2,232,200,000		$ 2,232,200,000	$ 2,092,200,000
Proceeds from issuance of long-term debt			140,000,000	165,000,000	$ 180,000,000
Avista Utilities [Member]
Debt Instrument [Line Items]
Secured Debt	$ 2,157,200,000		$ 2,157,200,000	2,017,200,000
Line of credit facility, maximum borrowing capacity						$ 400,000,000.0
First Mortgage [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	8.00%		8.00%
2032 \| Secured Debt [Member]
Debt Instrument [Line Items]
Pollution Control Bonds	$ 66,700,000		$ 66,700,000
2032 \| Secured Debt [Member] \| Avista Utilities [Member]
Debt Instrument [Line Items]
Pollution Control Bonds	66,700,000		$ 66,700,000	66,700,000
Maturity Year			2032
2034 \| Secured Debt [Member]
Debt Instrument [Line Items]
Pollution Control Bonds	17,000,000.0		$ 17,000,000.0
2034 \| Secured Debt [Member] \| Avista Utilities [Member]
Debt Instrument [Line Items]
Pollution Control Bonds	17,000,000		$ 17,000,000	17,000,000
Maturity Year			2034
2.90% Due in 2051 [Member] \| Line of Credit [Member]
Debt Instrument [Line Items]
Line of credit facility, maximum borrowing capacity	400,000,000.0		$ 400,000,000.0
2.90% Due in 2051 [Member] \| First Mortgage [Member]
Debt Instrument [Line Items]
Proceeds from issuance of long-term debt	70,000,000.0
2.90% Due in 2051 [Member] \| First Mortgage [Member] \| Interest Rate Swap [Member]
Debt Instrument [Line Items]
Number of interest rate swaps settled \| Contract			4
Notional Amount	45,000,000.0		$ 45,000,000.0
Net payments from settlement of derivatives			17,200,000
2.90% Due in 2051 [Member] \| First Mortgage [Member] \| Avista Utilities [Member]
Debt Instrument [Line Items]
Secured Debt	$ 140,000,000		$ 140,000,000
Proceeds from issuance of long-term debt		$ 70,000,000.0
Debt Instrument, Interest Rate, Stated Percentage	2.90%	2.90%	2.90%
Maturity Year		2051	2051
2050 3.07% \| First Mortgage [Member] \| Avista Utilities [Member]
Debt Instrument [Line Items]
Secured Debt	$ 165,000,000		$ 165,000,000	$ 165,000,000
Debt Instrument, Interest Rate, Stated Percentage	3.07%		3.07%
Maturity Year			2050