Derivative Accounting (Tables)

9 Months Ended

Sep. 30, 2025

Derivative Instruments and Hedging Activities Disclosure [Abstract]

Schedule of Outstanding Gross Notional Amount of Derivatives, which Represents Both Purchases and Sales

The following table shows the outstanding gross notional volume of energy derivatives, which represent both purchases and sales (does not reflect net position):

		Quantity
Commodity	Unit of Measure	September 30, 2025	December 31, 2024
Power	Gigawatt-hour	619	1,051
Gas	Billion cubic feet	241	235

Schedule of Gains and Losses from Derivative Instruments Not Designated as Accounting Hedges Instruments

The following table provides information about gains and losses from energy derivative instruments not designated as accounting hedging instruments (dollars in thousands):

	Financial Statement	Three Months Ended September 30,				Nine Months Ended September 30,
Commodity Contracts	Location	2025		2024		2025		2024
Net Loss Recognized in Income	Fuel and purchased power (a)	$	(67,368)	$	(59,485)	$	(26,598)	$	(118,179)

(a)Amounts are before the effect of PSA deferrals.

Schedule of the Entity's Fair Value of Risk Management Activities Reported on a Gross Basis and the Impacts on Offsetting Liabilities

The following tables provide information about the fair value of APS’s risk management activities reported on a gross basis and the impacts of offsetting.  These amounts relate to commodity contracts and are located in the assets and liabilities from risk management activities lines of APS’s Condensed Consolidated Balance Sheets.

As of September 30, 2025:  (dollars in thousands)	Gross  Recognized  Derivatives  (a)		Amounts  Offset (b)		Net  Recognized  Derivatives		Other  (c)		Amounts  Reported on  Balance Sheets
Current assets	$	17,605	$	(10,974)	$	6,631	$	5	$	6,636
Investments and other assets	16,207		(607)		15,600		—		15,600
Total assets	33,812		(11,581)		22,231		5		22,236
Current liabilities	(44,256)		10,974		(33,282)		(5,796)		(39,078)
Deferred credits and other	(607)		607		—		—		—
Total liabilities	(44,863)		11,581		(33,282)		(5,796)		(39,078)
Total	$	(11,051)	$	—	$	(11,051)	$	(5,791)	$	(16,842)

(a)All of our gross recognized derivative instruments were subject to master netting arrangements.

(b)No cash collateral has been provided to counterparties, or received from counterparties, that is subject to offsetting.

(c)Represents cash collateral and cash margin that is not subject to offsetting. Amounts relate to non-derivative instruments, derivatives qualifying for scope exceptions, or collateral and margin posted in excess of the recognized derivative instrument.  Includes cash collateral received from counterparties of $5,796 thousand and cash margin provided to counterparties of $5 thousand.

As of December 31, 2024:  (dollars in thousands)	Gross  Recognized  Derivatives  (a)		Amounts Offset  (b)		Net  Recognized  Derivatives		Other  (c)		Amounts  Reported on  Balance Sheets
Current assets	$	13,718	$	(3,158)	$	10,560	$	18	$	10,578
Investments and other assets	6,610		(630)		5,980		—		5,980
Total assets	20,328		(3,788)		16,540		18		16,558
Current liabilities	(52,527)		3,158		(49,369)		(2,971)		(52,340)
Deferred credits and other	(10,076)		630		(9,446)		—		(9,446)
Total liabilities	(62,603)		3,788		(58,815)		(2,971)		(61,786)
Total	$	(42,275)	$	—	$	(42,275)	$	(2,953)	$	(45,228)

(a)All of our gross recognized derivative instruments were subject to master netting arrangements.

(b)No cash collateral has been provided to counterparties, or received from counterparties, that is subject to offsetting.

(c)Represents cash collateral and cash margin that is not subject to offsetting.  Amounts relate to non-derivative instruments, derivatives qualifying for scope exceptions, or collateral and margin posted in excess of the recognized derivative instrument.  Includes cash collateral received from counterparties of $2,971 thousand and cash margin provided to counterparties of $18 thousand.

Schedule of the Entity's Fair Value of Risk Management Activities Reported on a Gross Basis and the Impacts on Offsetting Assets

The following tables provide information about the fair value of APS’s risk management activities reported on a gross basis and the impacts of offsetting.  These amounts relate to commodity contracts and are located in the assets and liabilities from risk management activities lines of APS’s Condensed Consolidated Balance Sheets.

As of September 30, 2025:  (dollars in thousands)	Gross  Recognized  Derivatives  (a)		Amounts  Offset (b)		Net  Recognized  Derivatives		Other  (c)		Amounts  Reported on  Balance Sheets
Current assets	$	17,605	$	(10,974)	$	6,631	$	5	$	6,636
Investments and other assets	16,207		(607)		15,600		—		15,600
Total assets	33,812		(11,581)		22,231		5		22,236
Current liabilities	(44,256)		10,974		(33,282)		(5,796)		(39,078)
Deferred credits and other	(607)		607		—		—		—
Total liabilities	(44,863)		11,581		(33,282)		(5,796)		(39,078)
Total	$	(11,051)	$	—	$	(11,051)	$	(5,791)	$	(16,842)

(a)All of our gross recognized derivative instruments were subject to master netting arrangements.

(b)No cash collateral has been provided to counterparties, or received from counterparties, that is subject to offsetting.

(c)Represents cash collateral and cash margin that is not subject to offsetting. Amounts relate to non-derivative instruments, derivatives qualifying for scope exceptions, or collateral and margin posted in excess of the recognized derivative instrument.  Includes cash collateral received from counterparties of $5,796 thousand and cash margin provided to counterparties of $5 thousand.

As of December 31, 2024:  (dollars in thousands)	Gross  Recognized  Derivatives  (a)		Amounts Offset  (b)		Net  Recognized  Derivatives		Other  (c)		Amounts  Reported on  Balance Sheets
Current assets	$	13,718	$	(3,158)	$	10,560	$	18	$	10,578
Investments and other assets	6,610		(630)		5,980		—		5,980
Total assets	20,328		(3,788)		16,540		18		16,558
Current liabilities	(52,527)		3,158		(49,369)		(2,971)		(52,340)
Deferred credits and other	(10,076)		630		(9,446)		—		(9,446)
Total liabilities	(62,603)		3,788		(58,815)		(2,971)		(61,786)
Total	$	(42,275)	$	—	$	(42,275)	$	(2,953)	$	(45,228)

(a)All of our gross recognized derivative instruments were subject to master netting arrangements.

(b)No cash collateral has been provided to counterparties, or received from counterparties, that is subject to offsetting.

(c)Represents cash collateral and cash margin that is not subject to offsetting.  Amounts relate to non-derivative instruments, derivatives qualifying for scope exceptions, or collateral and margin posted in excess of the recognized derivative instrument.  Includes cash collateral received from counterparties of $2,971 thousand and cash margin provided to counterparties of $18 thousand.

Schedule of Information about Derivative Instruments that have Credit-Risk-Related Contingent Features

The following table provides information about our energy derivative instruments that have credit-risk-related contingent features (dollars in thousands):

	September 30, 2025
Aggregate fair value of derivative instruments in a net liability position	$	44,863
Additional collateral in the event credit-risk related contingent features were fully triggered (a)	10,007

(a)This amount is after counterparty netting and includes those contracts which qualify for scope exceptions, which are excluded from the derivative details above.