Investments in Nuclear Decommissioning Trusts and Other Special Use Funds (Details) - APS - USD ($) $ in Thousands	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Nuclear decommissioning trust fund assets
Fair Value	$ 1,514,395		$ 1,514,395		$ 1,420,641
Total Unrealized Gains			381,803		337,994
Total Unrealized Losses			(58,187)		(69,091)
Amortized cost	1,028,000		1,028,000		927,000
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Realized gains	35,231	$ 6,282	36,441	$ 7,305
Realized losses	(11,192)	(12,439)	(16,886)	(19,674)
Proceeds from the sale of securities	340,902	330,432	567,528	691,670
Nuclear Decommissioning Trusts
Nuclear decommissioning trust fund assets
Fair Value	1,162,397		1,162,397		1,073,410
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Realized gains	35,231	6,282	36,441	7,305
Realized losses	(11,192)	(12,439)	(16,886)	(19,674)
Proceeds from the sale of securities	298,761	309,966	434,946	629,659
Other Special Use Funds
Nuclear decommissioning trust fund assets
Fair Value	351,998		351,998		347,231
Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds
Realized gains	0	0	0	0
Realized losses	0	0	0	0
Proceeds from the sale of securities	42,141	$ 20,466	132,582	$ 62,011
Equity securities
Nuclear decommissioning trust fund assets
Equity securities	546,349		546,349		554,214
Total Unrealized Gains			378,973		334,817
Total Unrealized Losses			(5)		(267)
Equity securities | Nuclear Decommissioning Trusts
Nuclear decommissioning trust fund assets
Equity securities	519,099		519,099		487,240
Equity securities | Other Special Use Funds
Nuclear decommissioning trust fund assets
Equity securities	27,250		27,250		66,974
Available for sale-fixed income securities
Nuclear decommissioning trust fund assets
Fair Value	972,774		972,774		861,637
Total Unrealized Gains			2,830		3,177
Total Unrealized Losses			(58,178)		(68,795)
Fair value of fixed income securities, summarized by contractual maturities
Less than one year	114,971		114,971
1 year – 5 years	355,424		355,424
5 years – 10 years	201,939		201,939
Greater than 10 years	300,440		300,440
Total	972,774		972,774
Available for sale-fixed income securities | Nuclear Decommissioning Trusts
Nuclear decommissioning trust fund assets
Fair Value	649,545		649,545		582,343
Fair value of fixed income securities, summarized by contractual maturities
Less than one year	19,020		19,020
1 year – 5 years	175,774		175,774
5 years – 10 years	158,261		158,261
Greater than 10 years	296,490		296,490
Total	649,545		649,545
Available for sale-fixed income securities | Other Special Use Funds
Nuclear decommissioning trust fund assets
Fair Value	323,229		323,229		279,294
Available for sale-fixed income securities | Coal Reclamation Escrow Account
Fair value of fixed income securities, summarized by contractual maturities
Less than one year	57,267		57,267
1 year – 5 years	35,020		35,020
5 years – 10 years	0		0
Greater than 10 years	3,950		3,950
Total	96,237		96,237
Available for sale-fixed income securities | Active Union Employee Medical Account
Fair value of fixed income securities, summarized by contractual maturities
Less than one year	38,684		38,684
1 year – 5 years	144,630		144,630
5 years – 10 years	43,678		43,678
Greater than 10 years	0		0
Total	226,992		226,992
Other
Nuclear decommissioning trust fund assets
Fair Value	(4,728)		(4,728)		4,790
Total Unrealized Gains			0		0
Total Unrealized Losses			(4)		(29)
Other | Nuclear Decommissioning Trusts
Nuclear decommissioning trust fund assets
Fair Value	(6,247)		(6,247)		3,827
Other | Other Special Use Funds
Nuclear decommissioning trust fund assets
Fair Value	$ 1,519		$ 1,519		$ 963