Commitments and Contingencies - PVNGS Liability and Insurance Matters (Details) - Palo Verde Nuclear Generating Station - Nuclear plant - Public Service Company of New Mexico $ in Millions	Sep. 30, 2026 USD ($) generatingUnit
Public Utilities, Commitments And Contingencies [Line Items]
Maximum retrospective premium per reactor	$ 165.9
Maximum annual premium per incident	$ 24.7
Number of nuclear power plants owned \| generatingUnit	3
Maximum potential assessment per incident	$ 12.1
Annual payment limitation related to incident	1.8
Aggregate amount of all risk insurance	2,800.0
Maximum amount under nuclear electric insurance limited	5.0
Commercial providers
Public Utilities, Commitments And Contingencies [Line Items]
Liability insurance coverage	500.0
Industry Wide Retrospective Assessment Program
Public Utilities, Commitments And Contingencies [Line Items]
Liability insurance coverage	15,900.0
Maximum
Public Utilities, Commitments And Contingencies [Line Items]
Liability insurance coverage	$ 16,400.0