Regulatory Matters - ACC General Retail Rate Cases (Details) $ in Thousands	Feb. 22, 2024 USD ($)	Jan. 25, 2024 USD ($) $ / MWh	Nov. 02, 2021 USD ($)
Public Utilities, General Disclosures [Line Items]
Revenue increase (decrease)	$ 491,700	$ 523,100
ACC
Public Utilities, General Disclosures [Line Items]
Recommended return on equity, percentage	9.55%	9.55%
Increment of fair value rate, percentage	0.25%	0.25%
ACC \| Navajo Nation \| Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Regulatory matters, amounts recoverable by rates			$ 10,000
ACC \| Navajo County Communities \| Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Regulatory matters, amounts recoverable by rates			500
ACC \| Navajo Nation, Hopi Tribe \| Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Regulatory matters, amounts recoverable by rates			1,000
ACC \| Navajo Nation, Electrification Projects \| Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Amount funded by shareholders			2,000
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 Nation, Hopi Reservation \| Coal Community Transition Plan
Public Utilities, General Disclosures [Line Items]
Regulatory matters, amounts recoverable by rates			$ 1,250
APS \| Retail Rate Case Filing with Arizona Corporation Commission \| ACC
Public Utilities, General Disclosures [Line Items]
Effective fair value percentage	4.39%	4.36%
Prepaid pension asset rate (in percent)		5.00%
Pension and other post-retirement and post employment benefit plans (in percent)		5.35%
Retention of REAC		$ 1,900
Transfer to LFCR		$ 27,100
Base fuel rate (in dollars per kWh) \| $ / MWh		0.006
Increases in annual revenue	$ 253,400
Increase to the typical residential customer’s bill (in percent)	8.00%