Regulatory Matters - Retail Rate Case Filing (Details) $ in Thousands	Feb. 22, 2024 USD ($)	Jan. 25, 2024 USD ($) $ / MWh	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 ($)	Dec. 17, 2021 USD ($)	Nov. 02, 2021 USD ($)	Apr. 30, 2024 USD ($)	Nov. 06, 2023 USD ($)	Nov. 05, 2023 USD ($)	Aug. 04, 2023 USD ($)	Aug. 03, 2023 USD ($)	Jun. 15, 2023 USD ($)	Mar. 06, 2023	Nov. 30, 2022 USD ($)
Public Utilities, General Disclosures [Line Items]
Revenue increase (decrease)	$ 491,700	$ 523,100
ACC
Public Utilities, General Disclosures [Line Items]
Base fuel rate (in dollars per kWh) | $ / kWh			0.006	0.006	0.004
Revenue increase (decrease)			$ 281,900	$ 383,100								$ 282,700	$ 281,900			$ 251,000
Alternative revenue increase (decrease)																$ 312,000
Recommended return on equity, percentage	9.55%	9.55%	9.68%	10.25%												9.60%
Increment of fair value rate, percentage	0.25%	0.25%	0.50%	0.50%												0.00%
Alternative increment of fair value rate percentage																0.0075
Hypothetical capital structure of equity layer percentage																0.46
ACC | Navajo Nation, Hopi Tribe | Coal Community Transition Plan | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Amount recoverable through rates related to the CCT											$ 1,000
ACC | Navajo Nation | Coal Community Transition Plan | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Amount funded by shareholders											1,500
Amount recoverable through rates related to the CCT											10,000
ACC | Navajo Nation, Hopi Reservation | Coal Community Transition Plan | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Amount recoverable through rates related to the CCT											1,250
ACC | Navajo County Communities | Coal Community Transition Plan | Subsequent Event
Public Utilities, General Disclosures [Line Items]
Amount recoverable through rates related to the CCT											500
ACC | Navajo County Communities, CCT and Economic Development | Coal Community Transition Plan | Subsequent Event
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 | Subsequent Event
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)												$ 376,200		$ 377,700	$ 383,100
Regulatory matters, customer bill impact rate				11.30%								11.10%		11.20%
Regulatory matters, no of basis penalty point										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
Base fuel rate (in dollars per kWh)		0.006					0.038321
Recommended return on equity, percentage									8.90%	8.70%
Effective fair value percentage	4.39%	4.36%
Public utilities, effective prepaid pension asset, rate		5.00%
Public utilities, effective other postretirement benefit plan liability rate		5.35%
Public utilities, retention of renewable energy adjustment charge		$ 1,900
Public utilities, recommended transfer of funds to base rates		$ 27,100
Increases in annual revenue	$ 253,400
Increase to the typical residential customer’s bill	8.00%
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 not recoverable										$ 215,500
Amount funded by shareholders										$ 1,000
Amount funded by shareholders, term										60 days
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 County Communities | Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Amount funded by shareholders										$ 500
Amount funded by shareholders, term										60 days
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
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%