Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	$ 6,159,876	$ 6,021,460
Ending balance	6,284,862	6,159,876
Accumulated Other Comprehensive Loss
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(31,435)	(54,861)
OCI (loss) before reclassifications	(3,707)	19,423
Amounts reclassified from accumulated other comprehensive loss	1,998	4,003
Ending balance	(33,144)	(31,435)
Pension and Other Postretirement Benefits
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(32,332)	(53,885)
OCI (loss) before reclassifications	(4,420)	17,550
Amounts reclassified from accumulated other comprehensive loss	1,998	4,003
Ending balance	(34,754)	(32,332)
Derivative Instruments
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	897	(976)
OCI (loss) before reclassifications	713	1,873
Amounts reclassified from accumulated other comprehensive loss	0	0
Ending balance	1,610	897
Arizona Public Service Company
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	7,052,955	6,750,473
Ending balance	7,349,136	7,052,955
Arizona Public Service Company | Accumulated Other Comprehensive Loss
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(15,596)	(34,880)
OCI (loss) before reclassifications	(3,383)	15,646
Amounts reclassified from accumulated other comprehensive loss	1,760	3,638
Ending balance	(17,219)	(15,596)
Arizona Public Service Company | Pension and Other Postretirement Benefits
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(15,596)	(34,880)
OCI (loss) before reclassifications	(3,383)	15,646
Amounts reclassified from accumulated other comprehensive loss	1,760	3,638
Ending balance	$ (17,219)	$ (15,596)