Changes in Accumulated Other Comprehensive Loss (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ (66,382)	$ (74,902)	$ (68,141)	$ (78,053)
OCI (loss) before reclassifications	(944)	(2,032)	(1,744)	(2,453)
Amounts reclassified from accumulated other comprehensive loss	1,726	2,717	4,285	6,289
Total other comprehensive income	782	685	2,541	3,836
Ending balance	(65,600)	(74,217)	(65,600)	(74,217)
Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(9,209)	(20,364)	(10,385)	(23,058)
OCI (loss) before reclassifications	25	40	(775)	(381)
Amounts reclassified from accumulated other comprehensive loss	874	1,955	2,850	5,070
Total other comprehensive income	899	1,995	2,075	4,689
Ending balance	(8,310)	(18,369)	(8,310)	(18,369)
Pension and other postretirement benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(57,173)	(54,538)	(57,756)	(54,995)
OCI (loss) before reclassifications	(969)	(2,072)	(969)	(2,072)
Amounts reclassified from accumulated other comprehensive loss	852	762	1,435	1,219
Total other comprehensive income	(117)	(1,310)	466	(853)
Ending balance	(57,290)	(55,848)	(57,290)	(55,848)
Arizona Public Service Company
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(46,476)	(50,111)	(48,333)	(53,372)
OCI (loss) before reclassifications	(902)	(2,001)	(1,702)	(2,422)
Amounts reclassified from accumulated other comprehensive loss	1,727	2,712	4,384	6,394
Total other comprehensive income	825	711	2,682	3,972
Ending balance	(45,651)	(49,400)	(45,651)	(49,400)
Arizona Public Service Company | Derivative Instruments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(9,209)	(20,364)	(10,385)	(23,059)
OCI (loss) before reclassifications	25	40	(775)	(381)
Amounts reclassified from accumulated other comprehensive loss	874	1,954	2,850	5,070
Total other comprehensive income	899	1,994	2,075	4,689
Ending balance	(8,310)	(18,370)	(8,310)	(18,370)
Arizona Public Service Company | Pension and other postretirement benefits
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(37,267)	(29,747)	(37,948)	(30,313)
OCI (loss) before reclassifications	(927)	(2,041)	(927)	(2,041)
Amounts reclassified from accumulated other comprehensive loss	853	758	1,534	1,324
Total other comprehensive income	(74)	(1,283)	607	(717)
Ending balance	$ (37,341)	$ (31,030)	$ (37,341)	$ (31,030)