Changes in Accumulated Other Comprehensive Loss (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	$ (74,217)	$ (104,457)	$ (78,053)	$ (114,008)
OCI (loss) before reclassifications	5,140	(145)	2,687	(1,882)
Amounts reclassified from accumulated other comprehensive loss	6,675	15,267	12,964	26,555
Total other comprehensive income	11,815	15,122	15,651	24,673
Ending balance	(62,402)	(89,335)	(62,402)	(89,335)
Derivative Instruments
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(18,369)	(40,319)	(23,058)	(49,592)
OCI (loss) before reclassifications	(91)	(145)	(472)	(247)
Amounts reclassified from accumulated other comprehensive loss	5,939	14,310	11,009	23,685
Total other comprehensive income	5,848	14,165	10,537	23,438
Ending balance	(12,521)	(26,154)	(12,521)	(26,154)
Pension and other postretirement benefits
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(55,848)	(64,138)	(54,995)	(64,416)
OCI (loss) before reclassifications	5,231	0	3,159	(1,635)
Amounts reclassified from accumulated other comprehensive loss	736	957	1,955	2,870
Total other comprehensive income	5,967	957	5,114	1,235
Ending balance	(49,881)	(63,181)	(49,881)	(63,181)
Arizona Public Service Company
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(49,400)	(79,552)	(53,372)	(89,095)
OCI (loss) before reclassifications	(91)	(145)	(2,513)	(1,877)
Amounts reclassified from accumulated other comprehensive loss	6,675	15,261	13,069	26,536
Total other comprehensive income	6,584	15,116	10,556	24,659
Ending balance	(42,816)	(64,436)	(42,816)	(64,436)
Arizona Public Service Company | Derivative Instruments
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(18,370)	(40,320)	(23,059)	(49,592)
OCI (loss) before reclassifications	(91)	(145)	(472)	(247)
Amounts reclassified from accumulated other comprehensive loss	5,940	14,310	11,010	23,684
Total other comprehensive income	5,849	14,165	10,538	23,437
Ending balance	(12,521)	(26,155)	(12,521)	(26,155)
Arizona Public Service Company | Pension and other postretirement benefits
Changes in accumulated other comprehensive income (loss) by component
Beginning balance	(31,030)	(39,232)	(30,313)	(39,503)
OCI (loss) before reclassifications	0	0	(2,041)	(1,630)
Amounts reclassified from accumulated other comprehensive loss	735	951	2,059	2,852
Total other comprehensive income	735	951	18	1,222
Ending balance	$ (30,295)	$ (38,281)	$ (30,295)	$ (38,281)