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Commitments and Contingencies (Details) |  |  |  |  |  |  |  |  |  | 3 Months Ended | 108 Months Ended |
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Mar. 22, 2022 USD ($) | Nov. 02, 2021 USD ($) | Nov. 01, 2021 USD ($) claim | Feb. 22, 2021 USD ($) | Jul. 03, 2018 USD ($) | Apr. 05, 2018 plaintiff defendant | Dec. 16, 2016 plaintiff | Jul. 06, 2016 | Aug. 06, 2013 defendant | Mar. 31, 2022 USD ($) powerPlant | Jun. 30, 2020 USD ($) timePeriod claim | Dec. 31, 1986 trust
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Production tax credit guarantees |  |  |  |  |  |  |  |  |  | $ 36,000,000 |  |
APS |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Maximum insurance against public liability per occurrence for a nuclear incident (up to) |  |  |  |  |  |  |  |  |  | 13,500,000,000 |  |
Maximum available nuclear liability insurance (up to) |  |  |  |  |  |  |  |  |  | 450,000,000 |  |
Remaining nuclear liability insurance through mandatory industry wide retrospective assessment program |  |  |  |  |  |  |  |  |  | 13,100,000,000 |  |
Maximum retrospective premium assessment per reactor for each nuclear liability incident |  |  |  |  |  |  |  |  |  | 137,600,000 |  |
Annual limit per incident with respect to maximum retrospective premium assessment |  |  |  |  |  |  |  |  |  | $ 20,500,000 |  |
Number of VIE lessor trusts |  |  |  |  |  |  |  |  |  | 3 |  | 3
Maximum potential retrospective assessment per incident of APS |  |  |  |  |  |  |  |  |  | $ 120,100,000 |  |
Annual payment limitation with respect to maximum potential retrospective premium assessment |  |  |  |  |  |  |  |  |  | 17,900,000 |  |
Amount of "all risk" (including nuclear hazards) insurance for property damage to, and decontamination of, property at Palo Verde |  |  |  |  |  |  |  |  |  | 2,800,000,000 |  |
Maximum amount that APS could incur under the current NEIL policies for each retrospective assessment |  |  |  |  |  |  |  |  |  | 22,300,000 |  |
Collateral assurance provided based on rating triggers |  |  |  |  |  |  |  |  |  | $ 62,800,000 |  |
Period to provide collateral assurance based on rating triggers |  |  |  |  |  |  |  |  |  | 20 days |  |
APS | Letters of Credit Expiring in 2023 |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Outstanding letters of credit |  |  |  |  |  |  |  |  |  | $ 8,000,000 |  |
APS | Surety Bonds Expiring in 2023 |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Surety bonds expiring, amount |  |  |  |  |  |  |  |  |  | 6,000,000 |  |
APS | Coal combustion waste | Four Corners |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Site contingency increase in loss exposure not accrued, best estimate |  |  |  |  |  |  |  |  |  | 30,000,000 |  |
APS | Coal combustion waste | Cholla | Minimum |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Site contingency increase in loss exposure not accrued, best estimate |  |  |  |  |  |  |  |  |  | 16,000,000 |  |
APS | Coal combustion waste | Navajo Plant |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Site contingency increase in loss exposure not accrued, best estimate |  |  |  |  |  |  |  |  |  | 1,000,000 |  |
APS | Coal combustion waste | Cholla and Four Corners | Minimum |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Site contingency increase in loss exposure not accrued, best estimate |  |  |  |  |  |  |  |  |  | 10,000,000 |  |
APS | Coal combustion waste | Cholla and Four Corners | Maximum |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Site contingency increase in loss exposure not accrued, best estimate |  |  |  |  |  |  |  |  |  | $ 15,000,000 |  |
APS | Four Corners Units 4 and 5 | Regional Haze Rules |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Percentage of share of cost of control |  |  |  |  |  |  |  |  |  | 63.00% |  |
Expected environmental cost |  |  |  |  |  |  |  |  |  | $ 400,000,000 |  |
APS | SCE | Four Corners Units 4 and 5 |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Disallowance of plant investments |  | $ 194,000,000 |  |  |  |  |  |  |  |  |  |
Cost deferrals |  | $ 215,500,000 |  |  |  |  |  |  |  |  |  |
Amount not recoverable |  |  |  |  |  |  |  |  |  | 154,400,000 |  |
APS | Contaminated groundwater wells |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Costs related to investigation and study under Superfund site |  |  |  |  |  |  |  |  |  | 3,000,000 |  |
Number of defendants against whom Roosevelt Irrigation District (RID) filed lawsuit | defendant |  |  |  |  |  | 28 |  |  | 24 |  |  |
Number of plaintiffs | plaintiff |  |  |  |  |  |  | 2 |  |  |  |  |
APS | Contaminated groundwater wells | Settled Litigation |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Number of plaintiffs | plaintiff |  |  |  |  |  | 2 |  |  |  |  |  |
APS | Public Utilities, Inventory, Fuel |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Increase in contractual obligations |  |  |  |  |  |  |  |  |  | 1,200,000,000 |  |
Increase in contractual obligations, lease arrangements |  |  |  |  |  |  |  |  |  | 500,000,000 |  |
Total fixed consideration paid for lease arrangements |  |  |  |  |  |  |  |  |  | 1,800,000,000 |  |
4C Acquisition, LLC | Four Corners |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Percentage of share of cost of control |  |  |  |  |  |  |  | 7.00% |  |  |  |
Notes receivable, related parties |  |  |  |  |  |  |  |  |  | $ 4,600,000 |  |
NTEC | Four Corners |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Option to purchase ownership interest (as a percent) |  |  |  |  | 7.00% |  |  | 7.00% |  |  |  |
Proceeds from operating and maintenance cost reimbursement |  |  |  |  | $ 70,000,000 |  |  |  |  |  |  |
Breach of Contract for Disposal of Spent Nuclear Fuel and/or High Level Radioactive Waste |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Litigation Settlement, Amount Awarded from Other Party | $ 12,100,000 |  | $ 12,200,000 |  |  |  |  |  |  |  | $ 111,800,000 |
Breach of Contract for Disposal of Spent Nuclear Fuel and/or High Level Radioactive Waste | APS |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Number of claims submitted | claim |  |  | 8 |  |  |  |  |  |  |  | 7 |
Number of settlement agreement time periods | timePeriod |  |  |  |  |  |  |  |  |  |  | 7 |
Litigation Settlement, Amount Awarded from Other Party | $ 3,500,000 |  | $ 3,600,000 |  |  |  |  |  |  |  | $ 32,500,000 |
2017 Settlement Agreement and its Customer Education and Outreach Plan | APS |  |  |  |  |  |  |  |  |  |  |  |
Commitments and Contingencies |  |  |  |  |  |  |  |  |  |  |  |
Settlement amount |  |  |  | $ 24,750,000 |  |  |  |  |  |  |  |
Settlement amount returned to customers |  |  |  | $ 24,000,000 |  |  |  |  |  |  |  |

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