Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	$ 6,284,862	$ 6,159,876
Other comprehensive income/(loss) before reclassifications	148	(3,707)
Amounts reclassified from accumulated other comprehensive loss	2,054	1,998
Ending balance	6,857,478	6,284,862
Accumulated Other Comprehensive Loss
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(33,144)	(31,435)
Ending balance	(30,942)	(33,144)
Pension and Other Postretirement Benefits
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(34,754)	(32,332)
Other comprehensive income/(loss) before reclassifications	1,039	(4,420)
Amounts reclassified from accumulated other comprehensive loss	2,054	1,998
Ending balance	(31,661)	(34,754)
Derivative Instruments
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	1,610	897
Other comprehensive income/(loss) before reclassifications	(891)	713
Amounts reclassified from accumulated other comprehensive loss	0	0
Ending balance	719	1,610
Arizona Public Service Company
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	7,349,136	7,052,955
Ending balance	8,376,332	7,349,136
Arizona Public Service Company | Accumulated Other Comprehensive Loss
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(17,219)	(15,596)
Ending balance	(14,116)	(17,219)
Arizona Public Service Company | Pension and Other Postretirement Benefits
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(17,219)	(15,596)
Other comprehensive income/(loss) before reclassifications	1,255	(3,383)
Amounts reclassified from accumulated other comprehensive loss	1,848	1,760
Ending balance	$ (14,116)	$ (17,219)