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Commitments and Contingencies - Palo Verde Nuclear Generating Station and Contractual Obligations (Details) |  | 3 Months Ended |
--- | --- | --- | ---
Aug. 18, 2014 USD ($) | Mar. 31, 2018 USD ($) power_plant time_period claim | Dec. 31, 2017 USD ($) | Dec. 31, 1986 Trust
Breach of Contract for Disposal of Spent Nuclear Fuel and/or High Level Radioactive Waste |  |  |  |
Commitments and Contingencies |  |  |  |
Litigation settlement amount | $ 57,400,000 |  | $ 9,000,000 |
Proceeds from legal settlements |  | $ 65,200,000 |  |
Arizona Public Service Company |  |  |  |
Commitments and Contingencies |  |  |  |
Maximum insurance against public liability per occurrence for a nuclear incident (up to) |  | 13,200,000,000 |  |
Maximum available nuclear liability insurance (up to) |  | 450,000,000 |  |
Remaining nuclear liability insurance through mandatory industry wide retrospective assessment program |  | 12,700,000,000 |  |
Maximum retrospective premium assessment per reactor for each nuclear liability incident |  | 127,300,000 |  |
Annual limit per incident with respect to maximum retrospective premium assessment |  | $ 19,000,000 |  |
Number of VIE lessor trusts |  | 3 |  | 3
Maximum potential retrospective assessment per incident of APS |  | $ 111,100,000 |  |
Annual payment limitation with respect to maximum potential retrospective premium assessment |  | 16,600,000 |  |
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 |  | 25,000,000 |  |
Collateral assurance provided based on rating triggers |  | $ 71,200,000 |  |
Period to provide collateral assurance based on rating triggers |  | 20 days |  |
Arizona Public Service Company | Breach of Contract for Disposal of Spent Nuclear Fuel and/or High Level Radioactive Waste |  |  |  |
Commitments and Contingencies |  |  |  |
Litigation settlement amount | $ 16,700,000 |  | $ 2,600,000 |
Number of claims submitted | claim |  | 3 |  |
Number of settlement agreement time periods | time_period |  | 3 |  |
Proceeds from legal settlements |  | $ 19,000,000 |  |

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- Definition Represents the "all risk" (including nuclear hazards) insurance for property damage to, and decontamination of, property at Palo Verde of which a substantial portion must first be applied to stabilization and decontamination. + References No definition available. + Details
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- Definition Represents the annual limit per incident with respect to the maximum assessment per reactor under the program for each nuclear incident, to be periodically adjusted for inflation. + References No definition available. + Details
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- Definition Represents the annual payment limitation with respect to maximum potential retrospective assessment. + References No definition available. + Details
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- Definition Represents the maximum insurance amount against public liability per occurrence for a nuclear incident. + References No definition available. + Details
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