Investments in Nuclear Decommissioning Trusts and Other Special Use Funds (Tables)

3 Months Ended

Mar. 31, 2022

Investments, Debt and Equity Securities [Abstract]

Fair value of APS's nuclear decommissioning trust fund assets

The following tables present the unrealized gains and losses based on the original cost of the investment and summarizes the fair value of APS’s nuclear decommissioning trusts and other special use fund assets (dollars in thousands):  

	March 31, 2022
	Fair Value							Total Unrealized Gains		Total Unrealized Losses
Investment Type:	Nuclear Decommissioning Trusts		Other Special Use Funds		Total
Equity securities	$	584,737	$	27,068	$	611,805		$	422,497	$	(37)
Available for sale-fixed income securities	642,250		320,862		963,112		(a)	8,653		(36,962)
Other	478		1,112		1,590		(b)	—		—
Total	$	1,227,465	$	349,042	$	1,576,507		$	431,150	$	(36,999)

(a)As of March 31, 2022, the amortized cost basis of these available-for-sale investments is $991 million.

(b)Represents net pending securities sales and purchases.

	December 31, 2021
	Fair Value							Total Unrealized Gains		Total Unrealized Losses
Investment Type:	Nuclear Decommissioning Trusts		Other Special Use Funds		Total
Equity securities	$	640,312	$	47,570	$	687,882		$	451,387	$	—
Available for sale-fixed income securities	682,227		309,904		992,131		(a)	24,283		(4,063)
Other	(27,782)		936		(26,846)		(b)	—		—
Total	$	1,294,757	$	358,410	$	1,653,167		$	475,670	$	(4,063)

(a)As of December 31, 2021, the amortized cost basis of these available-for-sale investments is $972 million.

(b)Represents net pending securities sales and purchases.

Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds

The following table sets forth APS’s realized gains and losses relating to the sale and maturity of available-for-sale debt securities and equity securities, and the proceeds from the sale and maturity of these investment securities (dollars in thousands):

	Three Months Ended March 31,
	Nuclear Decommissioning Trusts		Other Special Use Funds		Total
2022
Realized gains	$	1,023	$	—	$	1,023
Realized losses	(7,235)		—		(7,235)
Proceeds from the sale of securities (a)	319,693		41,545		361,238
2021
Realized gains	$	2,968	$	—	$	2,968
Realized losses	(4,148)		—		(4,148)
Proceeds from the sale of securities (a)	234,728		145,250		379,978

(a)    Proceeds are reinvested in the nuclear decommissioning trusts and other special use funds, excluding amounts reimbursed to the Company for active union employee medical claims from the active union employee medical account.

Fair value of fixed income securities, summarized by contractual maturities

The fair value of APS’s fixed income securities, summarized by contractual maturities, at March 31, 2022, is as follows (dollars in thousands):

	Nuclear Decommissioning Trusts		Coal Reclamation Escrow Account		Active Union Employee Medical Account		Total
Less than one year	$	18,119	$	41,906	$	40,463	$	100,488
1 year – 5 years	198,233		35,749		151,838		385,820
5 years – 10 years	139,957		1,749		44,205		185,911
Greater than 10 years	285,941		4,952		—		290,893
Total	$	642,250	$	84,356	$	236,506	$	963,112