Regulatory Matters - Cost Recovery Mechanisms (Details)																											1 Months Ended	9 Months Ended		12 Months Ended
	Jul. 12, 2022 USD ($) $ / kWh	Jun. 01, 2022 USD ($)	Feb. 15, 2022 USD ($)	Feb. 01, 2022 USD ($) $ / kWh $ / KWH_Kilowatt_hour	Nov. 01, 2021 $ / kWh	Oct. 01, 2021 USD ($) $ / kWh	Jun. 07, 2021 USD ($)	Jun. 01, 2021 USD ($)	Apr. 01, 2021 $ / kWh	Feb. 22, 2021 USD ($)	Feb. 15, 2021 USD ($)	Feb. 01, 2021 USD ($) $ / kWh	Aug. 20, 2020 USD ($) customer	Jun. 01, 2020 USD ($)	May 01, 2020 $ / kWh	Feb. 14, 2020 USD ($)	Feb. 01, 2020 $ / kWh	Nov. 14, 2019 USD ($) customer	Oct. 31, 2019 USD ($) $ / KWH_Kilowatt_hour	Oct. 29, 2019 USD ($)	May 01, 2019 $ / kWh	Apr. 10, 2019	Aug. 13, 2018 USD ($)	Nov. 20, 2017 USD ($)	Sep. 01, 2017 USD ($)	Mar. 27, 2017 $ / kWh	Mar. 31, 2021	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2020 USD ($) program MW	Dec. 31, 2017 $ / kWh	Dec. 31, 2017 $ / KWH_Kilowatt_hour	Jul. 01, 2022 USD ($)	Apr. 18, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 17, 2021 USD ($)	Dec. 09, 2021 USD ($)	Jul. 01, 2021 USD ($)	Jul. 01, 2020 USD ($)	May 15, 2020 USD ($)	May 05, 2020 USD ($)	Dec. 31, 2019 USD ($)	Jul. 01, 2019 USD ($)	Mar. 15, 2019 agreement	Dec. 31, 2018 USD ($)	Nov. 14, 2017 USD ($)
Change in regulatory asset
Deferred fuel and purchased power costs — current period																												$ 228,483,000	$ 224,541,000
Amounts charged to customers																												(171,607,000)	(25,195,000)
Rate plan comparison tool, number of customers | customer													3,800					13,000
Rate plan comparison tool, inconvenience payment													$ 25					$ 25
APS
Change in regulatory asset
Deferred fuel and purchased power costs — current period																												228,483,000	224,541,000
Amounts charged to customers																												$ (171,607,000)	(25,195,000)
Percentage increase under PSA effective for first billing cycle beginning April 2021																											50.00%
Remaining percentage increase under PSA effective for first billing cycle beginning November 2021																											50.00%
Demand side management funds																																									$ 36,000,000
Customer credits																																			$ 43,000,000
Customer credits, additional funds																																			$ 7,000,000
APS | 2017 Settlement Agreement and its Customer Education and Outreach Plan
Change in regulatory asset
Settlement amount										$ 24,750,000
Settlement amount returned to customers										$ 24,000,000
Lost Fixed Cost Recovery Mechanisms | APS
Change in regulatory asset
Fixed cost recoverable per power lost (in dollars per kWh)																															0.025	2.56
Percentage of retail revenues																												1.00%
Amount of adjustment representing prorated sales losses pending approval			$ 59,100,000								$ 38,500,000					$ 26,600,000
Increase (decrease) in amount of adjustment representing prorated sales losses			$ 32,500,000								$ 11,800,000					$ (9,600,000)
ACC | APS
Settlement Agreement
Program term																														18 years
Change in regulatory asset
Amount requested to be returned in form of tax savings to customers																			$ (184,000,000)				$ 86,500,000
Deferred taxes amortization, period																						28 years 6 months
Public Utilities, one-time bill credit																				$ 64,000,000
Public Utilities, one-time bill credit, additional benefit																				$ 39,500,000
Number of programs | program																														2
Solar capacity (in MW) | MW																														80
ACC | RES | APS
Settlement Agreement
Plan term																												5 years
ACC | RES 2018 | APS
Settlement Agreement
Amount of proposed budget																																	$ 86,200,000				$ 100,500,000	$ 93,100,000	$ 84,700,000				$ 86,300,000
Revenue requirements																																							$ 4,500,000
Authorized amount to be collected							$ 68,300,000
ACC | RES 2018 | APS | Solar Communities
Settlement Agreement
Program term																								3 years
ACC | Demand Side Management Adjustor Charge 2018 | APS
Settlement Agreement
Amount of proposed budget																									$ 52,600,000																					$ 52,600,000
ACC | Demand Side Management Adjustor Charge 2019 | APS
Settlement Agreement
Amount of proposed budget																																													$ 34,100,000
ACC | Demand Side Management Adjustor Charge 2020 | APS
Settlement Agreement
Amount of proposed budget																																								$ 51,900,000		$ 51,900,000
ACC | Power Supply Adjustor (PSA) | APS
Change in regulatory asset
Beginning balance						$ 375,181,000																						$ 388,148,000	175,835,000
Deferred fuel and purchased power costs — current period																												228,483,000	224,541,000
Amounts charged to customers																												(171,606,000)	(25,195,000)
Ending balance																												$ 445,025,000	$ 375,181,000	$ 175,835,000
PSA rate (in dollars per kWh) | $ / kWh				0.007544	0.003544				0.001544			0.003544					(0.000456)
PSA rate for prior year (in dollars per kWh) | $ / kWh				0.004842	(0.004444)				(0.004444)			0.003434					(0.002086)
Forward component of increase in PSA (in dollars per kWh)				0.012386	0.007988				0.005988			0.000110					0.001630
Fuel and purchased power costs above annual cap				$ 365,000,000								$ 215,900,000
ACC | Net Metering | APS
Change in regulatory asset
Cost of service, resource comparison proxy method, maximum annual percentage decrease	10.00%																								10.00%
Cost of service for interconnected DG system customers, grandfathered period																									20 years
Cost of service for new customers, guaranteed export price period																									10 years
Second-year export energy price (in dollars per kWh) | $ / kWh	0.0846					0.094									0.094						0.105
ACC | Demand Side Management Adjustor Charge 2021 | APS
Settlement Agreement
Amount of proposed budget																														$ 63,700,000
ACC | Demand Side Management Adjustor Charge 2022 | APS
Settlement Agreement
Amount of proposed budget																																				$ 78,400,000
Change in regulatory asset
Increase in proposed budget																																				$ 14,000,000
FERC | Environmental Improvement Surcharge | APS
Change in regulatory asset
Rate matter, environmental surcharge cap rate (in dollars per kWh) | $ / KWH_Kilowatt_hour				0.0005
Increase (decrease) in annual wholesale transmission rates												11,400,000
Rate matters, increase (decrease) in cost recovery, excess of annual amount												$ 1,100,000
FERC | Open Access Transmission Tariff | APS
Change in regulatory asset
Increase (decrease) in annual wholesale transmission rates		$ 33,000,000						$ 4,000,000						$ (6,100,000)
Increase (decrease) in wholesale customer rates		(6,400,000)						(3,200,000)						4,800,000
Increase (decrease) in retail customer rates		26,600,000						7,200,000						(10,900,000)
Increase (decrease) in retail revenue requirements		$ (2,400,000)						$ (28,400,000)						$ (7,400,000)
Cost Recovery Mechanisms | ACC | Power Supply Adjustor (PSA) | APS
Change in regulatory asset
Historical component of increase in PSA (in dollars per kWh) | $ / kWh				0.004								0.004					(0.002115)
Cost recovery, number of agreements | agreement																																												2
Minimum | ACC | APS
Change in regulatory asset
Operating results																			$ (69,000,000)
Minimum | ACC | RES 2018 | APS
Change in regulatory asset
Authorized spending	$ 20,000,000
Minimum | ACC | RES 2018 | APS | Solar Communities
Settlement Agreement
Required annual capital investment																								$ 10,000,000
Minimum | ACC | Retail Rate Case Filing with Arizona Corporation Commission | APS
Change in regulatory asset
Rate matter, environmental surcharge cap rate (in dollars per kWh) | $ / kWh																										0.00016
Minimum | FERC | Environmental Improvement Surcharge | APS
Change in regulatory asset
Rate matter, environmental surcharge cap rate amount				$ 13,000,000
Maximum | Retail Rate Case Filing with Arizona Corporation Commission | APS
Change in regulatory asset
Fixed cost recoverable per power lost (in dollars per kWh) | $ / KWH_Kilowatt_hour																			2.68
Maximum | ACC | RES 2018 | APS
Change in regulatory asset
Authorized spending	$ 30,000,000
Maximum | ACC | RES 2018 | APS | Solar Communities
Settlement Agreement
Required annual capital investment																								$ 15,000,000
Maximum | ACC | Retail Rate Case Filing with Arizona Corporation Commission | APS
Change in regulatory asset
Rate matter, environmental surcharge cap rate (in dollars per kWh) | $ / kWh																										0.00050
Maximum | FERC | Environmental Improvement Surcharge | APS
Change in regulatory asset
Rate matter, environmental surcharge cap rate amount				$ 14,000,000
Damage from Fire, Explosion or Other Hazard | APS
Change in regulatory asset
Past due balance threshold qualifying for payment extension																																		$ 75