v3.25.1
Commitments and Contingencies (Details)
$ in Millions
3 Months Ended 148 Months Ended
Jan. 01, 2024
USD ($)
trust
Jan. 17, 2023
USD ($)
Sep. 30, 2022
USD ($)
Jul. 03, 2018
Mar. 31, 2025
USD ($)
trust
timePeriod
Oct. 31, 2023
claim
Schedule of Commitments and Contingencies [Line Items]            
Production tax credit guarantees         $ 28.0  
Arizona Public Service Company and Palo Verde Owners vs. United States Department of Energy - Spent Nuclear Fuel and Waste Disposal            
Schedule of Commitments and Contingencies [Line Items]            
Settlement amount, awarded to company         $ 174.3  
APS            
Schedule of Commitments and Contingencies [Line Items]            
Maximum insurance against public liability per occurrence for a nuclear incident $ 16,300.0          
Maximum available nuclear liability insurance 500.0          
Remaining nuclear liability insurance through mandatory industry wide retrospective assessment program 15,800.0          
Maximum assessment per reactor for each nuclear incident 165.9          
Annual limit per incident with respect to maximum assessment $ 24.7          
Number of VIE lessor trusts | trust 3       3  
Maximum potential retrospective assessment per incident of APS $ 144.9          
Annual payment limitation with respect to maximum potential retrospective assessment $ 21.6          
Amount of "all risk" (including nuclear hazards) insurance for property damage to, and decontamination of, property at Palo Verde         $ 2,800.0  
Request second-year energy price for exported energy         24.2  
Collateral assurance based on rating triggers         $ 66.4  
Period to provide collateral assurance based on rating triggers         20 days  
APS | Surety Bonds Expiring in 2025            
Schedule of Commitments and Contingencies [Line Items]            
Surety bonds expiring, amount         $ 22.8  
APS | Letter of Credit            
Schedule of Commitments and Contingencies [Line Items]            
Outstanding letters of credit         18.7  
APS | Contaminated Groundwater Wells            
Schedule of Commitments and Contingencies [Line Items]            
Costs related to investigation and study under Superfund site         $ 3.0  
Remedial investigation work   $ 1.7        
APS | Contaminated Groundwater Wells | Pending Litigation            
Schedule of Commitments and Contingencies [Line Items]            
Settlement amount     $ 8.3      
APS | Arizona Public Service Company and Palo Verde Owners vs. United States Department of Energy - Spent Nuclear Fuel and Waste Disposal            
Schedule of Commitments and Contingencies [Line Items]            
Number of claims submitted | claim           11
Gain contingency, number of settlement agreement time periods | timePeriod         11  
Settlement amount, awarded to company         $ 50.7  
NTEC | Four Corners            
Schedule of Commitments and Contingencies [Line Items]            
Asset purchase agreement, option to purchase, ownership interest, percentage       7.00%