Jointly-Owned Facilities (Details) (ARIZONA PUBLIC SERVICE COMPANY, USD $) In Thousands, unless otherwise specified	Dec. 31, 2014
Palo Verde Units 1 and 3
Interests in jointly-owned facilities
Percent Owned	29.10%
Plant in Service	$ 1,734,918
Accumulated Depreciation	1,051,670
Construction Work in Progress	16,955
Palo Verde Unit 2
Interests in jointly-owned facilities
Percent Owned	16.80%
Plant in Service	556,472
Accumulated Depreciation	349,960
Construction Work in Progress	13,710
Palo Verde Common
Interests in jointly-owned facilities
Percent Owned	28.00%
Plant in Service	612,190
Accumulated Depreciation	224,208
Construction Work in Progress	68,896
Palo Verde Sale Leaseback
Interests in jointly-owned facilities
Plant in Service	351,050
Accumulated Depreciation	229,795
Construction Work in Progress	0
Four Corners Units 4, 5 and Common
Interests in jointly-owned facilities
Percent Owned	63.00%
Plant in Service	811,648
Accumulated Depreciation	578,772
Construction Work in Progress	33,150
Navajo Generating Station Units 1, 2 and 3
Interests in jointly-owned facilities
Percent Owned	14.00%
Plant in Service	272,208
Accumulated Depreciation	159,198
Construction Work in Progress	2,716
Cholla common facilities
Interests in jointly-owned facilities
Percent Owned	63.30%
Plant in Service	155,856
Accumulated Depreciation	49,954
Construction Work in Progress	866
ANPP 500kV System
Interests in jointly-owned facilities
Percent Owned	33.60%
Plant in Service	106,369
Accumulated Depreciation	35,035
Construction Work in Progress	3,731
Navajo Southern System
Interests in jointly-owned facilities
Percent Owned	22.50%
Plant in Service	59,994
Accumulated Depreciation	18,119
Construction Work in Progress	1,113
Palo Verde - Yuma 500kV System
Interests in jointly-owned facilities
Percent Owned	18.20%
Plant in Service	12,925
Accumulated Depreciation	4,943
Construction Work in Progress	12
Four Corners Switchyards
Interests in jointly-owned facilities
Percent Owned	47.50%
Plant in Service	33,034
Accumulated Depreciation	10,035
Construction Work in Progress	386
Phoenix - Mead System
Interests in jointly-owned facilities
Percent Owned	17.10%
Plant in Service	39,777
Accumulated Depreciation	12,843
Construction Work in Progress	105
Palo Verde - Estrella 500kV System
Interests in jointly-owned facilities
Percent Owned	50.00%
Plant in Service	89,572
Accumulated Depreciation	16,491
Construction Work in Progress	736
Morgan-Pinnacle Peak System
Interests in jointly-owned facilities
Percent Owned	64.40%
Plant in Service	130,840
Accumulated Depreciation	8,970
Construction Work in Progress	1,690
Round Valley System
Interests in jointly-owned facilities
Percent Owned	50.00%
Plant in Service	497
Accumulated Depreciation	276
Construction Work in Progress	1
Palo Verde - Morgan System
Interests in jointly-owned facilities
Percent Owned	90.00%
Plant in Service	0
Accumulated Depreciation	0
Construction Work in Progress	69,377
Hassayampa - North Gila System
Interests in jointly-owned facilities
Percent Owned	80.00%
Plant in Service	8,902
Accumulated Depreciation	3,634
Construction Work in Progress	$ 142,645