Jointly-Owned Facilities (Details) - ARIZONA PUBLIC SERVICE COMPANY $ in Thousands	Dec. 31, 2015 USD ($)
Palo Verde Units 1 and 3
Interests in jointly-owned facilities
Percent Owned	29.10%
Plant in Service	$ 1,744,137
Accumulated Depreciation	1,067,376
Construction Work in Progress	$ 22,228
Palo Verde Unit 2
Interests in jointly-owned facilities
Percent Owned	16.80%
Plant in Service	$ 583,633
Accumulated Depreciation	356,767
Construction Work in Progress	$ 4,142
Palo Verde Common
Interests in jointly-owned facilities
Percent Owned	28.00%
Plant in Service	$ 643,201
Accumulated Depreciation	231,609
Construction Work in Progress	64,069
Palo Verde Sale Leaseback
Interests in jointly-owned facilities
Plant in Service	351,050
Accumulated Depreciation	233,665
Construction Work in Progress	$ 0
Four Corners Units 4, 5 and Common
Interests in jointly-owned facilities
Percent Owned	63.00%
Plant in Service	$ 857,555
Accumulated Depreciation	577,321
Construction Work in Progress	$ 77,317
Navajo Generating Station Units 1, 2 and 3
Interests in jointly-owned facilities
Percent Owned	14.00%
Plant in Service	$ 274,640
Accumulated Depreciation	168,132
Construction Work in Progress	$ 4,460
Cholla common facilities
Interests in jointly-owned facilities
Percent Owned	63.30%
Plant in Service	$ 158,623
Accumulated Depreciation	53,777
Construction Work in Progress	$ 1,390
ANPP 500kV System
Interests in jointly-owned facilities
Percent Owned	33.40%
Plant in Service	$ 109,348
Accumulated Depreciation	36,576
Construction Work in Progress	$ 1,594
Navajo Southern System
Interests in jointly-owned facilities
Percent Owned	22.70%
Plant in Service	$ 62,139
Accumulated Depreciation	19,361
Construction Work in Progress	$ 397
Palo Verde - Yuma 500kV System
Interests in jointly-owned facilities
Percent Owned	19.30%
Plant in Service	$ 14,043
Accumulated Depreciation	5,226
Construction Work in Progress	$ 133
Four Corners Switchyards
Interests in jointly-owned facilities
Percent Owned	49.80%
Plant in Service	$ 38,420
Accumulated Depreciation	9,833
Construction Work in Progress	$ 1,687
Phoenix - Mead System
Interests in jointly-owned facilities
Percent Owned	17.10%
Plant in Service	$ 39,089
Accumulated Depreciation	13,173
Construction Work in Progress	$ 151
Palo Verde - Estrella 500kV System
Interests in jointly-owned facilities
Percent Owned	50.00%
Plant in Service	$ 89,832
Accumulated Depreciation	18,359
Construction Work in Progress	$ 1,008
Morgan-Pinnacle Peak System
Interests in jointly-owned facilities
Percent Owned	64.60%
Plant in Service	$ 129,855
Accumulated Depreciation	11,087
Construction Work in Progress	$ 2,592
Round Valley System
Interests in jointly-owned facilities
Percent Owned	50.00%
Plant in Service	$ 703
Accumulated Depreciation	286
Construction Work in Progress	$ 0
Palo Verde - Morgan System
Interests in jointly-owned facilities
Percent Owned	87.70%
Plant in Service	$ 12
Accumulated Depreciation	0
Construction Work in Progress	$ 133,813
Hassayampa - North Gila System
Interests in jointly-owned facilities
Percent Owned	80.00%
Plant in Service	$ 164,854
Accumulated Depreciation	1,159
Construction Work in Progress	$ 0
Cholla 500 Switchyard
Interests in jointly-owned facilities
Percent Owned	85.70%
Plant in Service	$ 547
Accumulated Depreciation	15
Construction Work in Progress	$ 0
Saquaro 500 Switchyard
Interests in jointly-owned facilities
Percent Owned	75.00%
Plant in Service	$ 773
Accumulated Depreciation	26
Construction Work in Progress	$ 0