Regulatory Matters - ACC General Retail Rate Cases (Details) $ in Thousands	Jun. 13, 2025 USD ($) $ / MWh	Feb. 22, 2024 USD ($)	Oct. 31, 2019 USD ($)
Public Utilities, General Disclosures [Line Items]
Revenue increase (decrease)		$ 491,700
ACC
Public Utilities, General Disclosures [Line Items]
Recommended return on equity, percentage		9.55%
Increment of fair value rate, percentage		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
ACC | Rate Case Filing with Arizona Corporation Commission | ACC
Public Utilities, General Disclosures [Line Items]
Base fuel and purchased power costs rate (in dollars per kWh) | $ / MWh	0.043881
APS | ACC
Public Utilities, General Disclosures [Line Items]
Proposed base rate increase	$ 579,500
Total revenue deficiency	$ 662,400
APS | Rate Case Filing with Arizona Corporation Commission | ACC
Public Utilities, General Disclosures [Line Items]
Approximate percentage of increase in average residential customer bill	13.99%
Rate matter, cost base rate	$ 12,500,000
Effective fair value percentage		4.39%