Jointly-Owned Facilities (Details) - Arizona Public Service Company $ in Thousands	Dec. 31, 2021 USD ($)
Palo Verde Units 1 and 3
Interests in jointly-owned facilities
Percent owned	29.10%
Plant in service	$ 1,932,629
Accumulated depreciation	1,113,905
Construction work in progress	$ 28,288
Palo Verde Unit 2
Interests in jointly-owned facilities
Percent owned	16.80%
Plant in service	$ 657,102
Accumulated depreciation	384,193
Construction work in progress	$ 14,084
Palo Verde Common
Interests in jointly-owned facilities
Percent owned	28.00%
Plant in service	$ 792,849
Accumulated depreciation	334,804
Construction work in progress	43,690
Palo Verde Sale Leaseback
Interests in jointly-owned facilities
Plant in service	351,050
Accumulated depreciation	256,884
Construction work in progress	$ 0
Four Corners Generating Station
Interests in jointly-owned facilities
Percent owned	63.00%
Plant in service	$ 1,686,702
Accumulated depreciation	608,247
Construction work in progress	$ 21,515
Cholla Common Facilities
Interests in jointly-owned facilities
Percent owned	50.50%
Plant in service	$ 208,709
Accumulated depreciation	121,877
Construction work in progress	$ 1,608
ANPP 500kV System
Interests in jointly-owned facilities
Percent owned	33.50%
Plant in service	$ 133,289
Accumulated depreciation	53,708
Construction work in progress	$ 115
Navajo Southern System
Interests in jointly-owned facilities
Percent owned	26.80%
Plant in service	$ 89,895
Accumulated depreciation	35,144
Construction work in progress	$ 1,535
Palo Verde — Yuma 500kV System
Interests in jointly-owned facilities
Percent owned	25.80%
Plant in service	$ 23,650
Accumulated depreciation	7,188
Construction work in progress	$ 716
Four Corners Switchyards
Interests in jointly-owned facilities
Percent owned	60.10%
Plant in service	$ 73,133
Accumulated depreciation	18,637
Construction work in progress	$ 258
Phoenix — Mead System
Interests in jointly-owned facilities
Percent owned	17.10%
Plant in service	$ 39,523
Accumulated depreciation	20,150
Construction work in progress	$ 0
Palo Verde — Rudd 500kV System
Interests in jointly-owned facilities
Percent owned	50.00%
Plant in service	$ 96,376
Accumulated depreciation	29,426
Construction work in progress	$ 0
Morgan — Pinnacle Peak System
Interests in jointly-owned facilities
Percent owned	64.70%
Plant in service	$ 119,814
Accumulated depreciation	23,575
Construction work in progress	$ 138
Round Valley System
Interests in jointly-owned facilities
Percent owned	50.00%
Plant in service	$ 535
Accumulated depreciation	180
Construction work in progress	$ 0
Palo Verde — Morgan System
Interests in jointly-owned facilities
Percent owned	87.80%
Plant in service	$ 259,180
Accumulated depreciation	27,995
Construction work in progress	$ 268
Hassayampa — North Gila System
Interests in jointly-owned facilities
Percent owned	80.00%
Plant in service	$ 148,039
Accumulated depreciation	19,317
Construction work in progress	$ 0
Cholla 500kV Switchyard
Interests in jointly-owned facilities
Percent owned	85.70%
Plant in service	$ 8,287
Accumulated depreciation	2,163
Construction work in progress	$ 5
Saguaro 500kV Switchyard
Interests in jointly-owned facilities
Percent owned	60.00%
Plant in service	$ 21,655
Accumulated depreciation	13,471
Construction work in progress	$ 0
Kyrene — Knox System
Interests in jointly-owned facilities
Percent owned	50.00%
Plant in service	$ 578
Accumulated depreciation	328
Construction work in progress	$ 0