Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Regulatory Matters - Cholla and Navajo Plant (Details) - APS - USD ($) $ in Millions	Sep. 30, 2025	Apr. 30, 2025
Navajo Nation, Economic Development Organization \| Coal Community Transition Plan \| Rate Case Filing with Arizona Corporation Commission \| ACC
Acquisition
Disallowance of annual amortization percentage	15.00%
Retired power plant costs
Acquisition
Net book value	$ 24.7
Cholla Units 1 & 3
Acquisition
Net book value		$ 81.0
Navajo Plant
Acquisition
Net book value	26.2
Navajo Plant, Coal Reclamation Regulatory Asset
Acquisition
Net book value	$ 3.6