Regulatory Matters - Retail Rate Case Filing (Details) $ in Thousands											9 Months Ended
	Jul. 26, 2023 USD ($) $ / kWh	Jul. 12, 2023 USD ($) $ / kWh	Jul. 11, 2023 $ / kWh	Jun. 14, 2023 USD ($)	Oct. 28, 2022 USD ($) $ / kWh	Jun. 30, 2022 USD ($)	Dec. 17, 2021 USD ($)	Oct. 27, 2021 USD ($)	Aug. 02, 2021 USD ($)	Mar. 27, 2017 USD ($)	Sep. 30, 2023 USD ($)	Aug. 04, 2023 USD ($)	Aug. 03, 2023 USD ($)	Jun. 15, 2023 USD ($)	Jun. 05, 2023	Mar. 06, 2023	Nov. 30, 2022 USD ($)	Apr. 30, 2022 USD ($)
ACC
Public Utilities, General Disclosures [Line Items]
Revenue increase (decrease)	$ 281,900	$ 383,100												$ 251,000
Alternative revenue increase (decrease)														$ 312,000
Recommended return on equity, percentage	9.68%	10.25%												9.60%
Increment of fair value rate, percentage	0.50%	0.50%												0.00%
Alternative increment of fair value rate percentage														0.0075
Hypothetical capital structure of equity layer percentage															0.46
Base fuel rate (in dollars per kWh) | $ / kWh	0.006	0.006	0.004
ACC | Navajo Nation, Hopi Tribe | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Amount recoverable through rates related to the CCT																		$ 1,000
ACC | Navajo Nation | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Amount recoverable through rates related to the CCT											$ 6,660
ACC | Navajo Nation, Hopi Reservation | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Amount recoverable through rates related to the CCT																		1,250
ACC | Navajo County Communities | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Amount recoverable through rates related to the CCT																		500
ACC | Navajo Nation, Electrification Projects | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Amount funded by shareholders																		1,000
ACC | Navajo County Communities, CCT and Economic Development | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Amount funded by shareholders																		1,100
ACC | Navajo Nation, Hopi Tribe for CCT and Economic Development | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Amount funded by shareholders																		$ 1,250
ACC | Navajo and Hopi Tribes | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Disbursement																	$ 1,250
ACC | APS
Public Utilities, General Disclosures [Line Items]
Total revenue deficiency					$ 772,000
Revenue increase (decrease)												$ 377,700	$ 383,100
Regulatory matters, customer bill impact rate		11.30%										11.20%
Regulatory matters, no of basis penalty point							0.0020	0.0020								20
Reversal of basis point penalty				0.0020
ACC | APS | Retail Rate Case Filing with Arizona Corporation Commission
Public Utilities, General Disclosures [Line Items]
Approximate percentage of increase in average residential customer bill					13.60%
Rate matter, cost base rate						$ 10,500,000
Revenue increase (decrease)									$ (111,000)
Recommended return on equity, percentage							8.90%	8.70%	9.16%
Increment of fair value rate, percentage									0.30%
Base fuel rate (in dollars per kWh) | $ / kWh					0.038321
Reduction on equity percentage									0.03%
Effective fair value percentage									4.95%
Net retail base rate, increase										$ 94,600
Non-fuel and non-depreciation base rate, increase										87,200
Fuel-related base rate decrease										53,600
Base rate increase, changes in depreciation schedules										$ 61,000
ACC | APS | Retail Rate Case Filing with Arizona Corporation Commission | Navajo Nation, Economic Development Organization | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Disallowance of annual amortization percentage									15.00%
Amount funded by customers									$ 50,000
Amount funded by customers, term									10 years
ACC | APS | Retail Rate Case Filing with Arizona Corporation Commission | Navajo County Communities | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Amount funded by shareholders								$ 500	$ 5,000
Amount funded by shareholders, term								60 days	5 years
ACC | APS | Retail Rate Case Filing with Arizona Corporation Commission | Navajo Nation, Hopi Tribe | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Amount funded by shareholders								$ 1,000	$ 1,675
Amount funded by shareholders, term								60 days
Amount not recoverable								$ 215,500
ACC | APS | Retail Rate Case Filing with Arizona Corporation Commission | Navajo Nation | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Amount funded by shareholders								$ 10,000
Amount funded by shareholders, term								3 years
ACC | APS | Retail Rate Case Filing with Arizona Corporation Commission | Navajo Nation, Hopi Reservation | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Amount funded by shareholders								$ 1,250
ACC | APS | Retail Rate Case Filing with Arizona Corporation Commission | Navajo Nation Reservation | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Revenue increase (decrease)								(4,800)
Recommended return on equity, percentage				8.70%
Amount funded by shareholders								$ 1,250
Disallowance of plant investments							$ 215,500
Requested reversal of rate adjustment				$ 215,500
Lost revenue recovery				$ 59,600							6,400
Lost revenue recovery collected											$ 6,400
Residential Utility Consumer Office | ACC
Public Utilities, General Disclosures [Line Items]
Revenue increase (decrease)														$ 84,900
Recommended return on equity, percentage														8.20%
Increment of fair value rate, percentage														0.00%
Alternate recommended return on equity percentage														0.087
Minimum | ACC | APS
Public Utilities, General Disclosures [Line Items]
Annual increase in retail base rates					$ 460,000
Maximum | ACC
Public Utilities, General Disclosures [Line Items]
Increment of fair value rate, percentage			1.00%