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Commitments and Contingencies - Palo Verde Nuclear Generating Station and Contractual Obligations (Details) |  |  |  | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | --- | ---
Feb. 01, 2017 USD ($) | Jan. 01, 2017 USD ($) | Aug. 18, 2014 USD ($) | Sep. 30, 2016 USD ($) | Dec. 31, 2016 USD ($) Trust time_period claim | Dec. 31, 2015 USD ($) | Dec. 31, 2014 USD ($) | Dec. 31, 1986 Trust
ARIZONA PUBLIC SERVICE COMPANY |  |  |  |  |  |  |  |
Palo Verde Nuclear Generating Station [Abstract] |  |  |  |  |  |  |  |
Maximum insurance against public liability per occurrence for a nuclear incident |  |  |  |  | $ 13,400,000,000.0 |  |  |
Maximum available nuclear liability insurance |  |  |  | $ 375,000,000 |  |  |  |
Remaining nuclear liability insurance through mandatory industry wide retrospective assessment program |  |  |  |  | 13,100,000,000 |  |  |
Maximum assessment per reactor for each nuclear incident |  |  |  |  | 127,300,000 |  |  |
Annual limit per incident with respect to maximum assessment |  |  |  |  | $ 18,900,000.0 |  |  |
Number of VIE lessor trusts | Trust |  |  |  |  | 3 |  |  | 3
Maximum potential retrospective assessment per incident of APS |  |  |  |  | $ 111,100,000 |  |  |
Annual payment limitation with respect to maximum potential retrospective 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 |  |  |  |  | 23,800,000 |  |  |
Collateral assurance provided based on rating triggers |  |  |  |  | $ 64,000,000 |  |  |
Period to provide collateral assurance based on rating triggers |  |  |  |  | 20 days |  |  |
Fuel and Purchased Power Commitments and Purchase Obligations [Abstract] |  |  |  |  |  |  |  |
2017 |  |  |  |  | $ 977,000,000 |  |  |
2018 |  |  |  |  | 737,000,000 |  |  |
2019 |  |  |  |  | 598,000,000 |  |  |
2020 |  |  |  |  | 525,000,000 |  |  |
2021 |  |  |  |  | 524,000,000 |  |  |
Thereafter |  |  |  |  | 7,300,000,000 |  |  |
ARIZONA PUBLIC SERVICE COMPANY | Coal take-or-pay commitments |  |  |  |  |  |  |  |
Fuel and Purchased Power Commitments and Purchase Obligations [Abstract] |  |  |  |  |  |  |  |
2017 |  |  |  |  | 195,428,000 |  |  |
2018 |  |  |  |  | 189,588,000 |  |  |
2019 |  |  |  |  | 193,818,000 |  |  |
2020 |  |  |  |  | 198,160,000 |  |  |
2021 |  |  |  |  | 202,619,000 |  |  |
Thereafter |  |  |  |  | 2,068,355,000 |  |  |
Total obligation |  |  |  |  | 3,047,968,000 |  |  |
Present value of commitments |  |  |  |  | 2,100,000,000 |  |  |
Total purchases |  |  |  |  | 160,066,000 | $ 211,327,000 | $ 236,773,000 |
ARIZONA PUBLIC SERVICE COMPANY | Renewable energy credits |  |  |  |  |  |  |  |
Fuel and Purchased Power Commitments and Purchase Obligations [Abstract] |  |  |  |  |  |  |  |
2017 |  |  |  |  | 40,000,000 |  |  |
2018 |  |  |  |  | 40,000,000 |  |  |
2019 |  |  |  |  | 40,000,000 |  |  |
2020 |  |  |  |  | 40,000,000 |  |  |
2021 |  |  |  |  | 40,000,000 |  |  |
Thereafter |  |  |  |  | 420,000,000 |  |  |
ARIZONA PUBLIC SERVICE COMPANY | Coal Mine Reclamation Obligations |  |  |  |  |  |  |  |
Fuel and Purchased Power Commitments and Purchase Obligations [Abstract] |  |  |  |  |  |  |  |
2017 |  |  |  |  | 17,000,000 |  |  |
2018 |  |  |  |  | 18,000,000 |  |  |
2019 |  |  |  |  | 19,000,000 |  |  |
2020 |  |  |  |  | 21,000,000 |  |  |
2021 |  |  |  |  | 22,000,000 |  |  |
Thereafter |  |  |  |  | 241,000,000 |  |  |
ARIZONA PUBLIC SERVICE COMPANY | Coal Mine Reclamation Balance Sheet Obligations |  |  |  |  |  |  |  |
Fuel and Purchased Power Commitments and Purchase Obligations [Abstract] |  |  |  |  |  |  |  |
Total obligation |  |  |  |  | 207,000,000 | $ 202,000,000 |  |
4CA | Coal Mine Reclamation Obligations |  |  |  |  |  |  |  |
Fuel and Purchased Power Commitments and Purchase Obligations [Abstract] |  |  |  |  |  |  |  |
2017 |  |  |  |  | 1,000,000 |  |  |
2018 |  |  |  |  | 1,000,000 |  |  |
2019 |  |  |  |  | 1,000,000 |  |  |
2020 |  |  |  |  | 1,000,000 |  |  |
2021 |  |  |  |  | 2,000,000 |  |  |
Thereafter |  |  |  |  | 17,000,000 |  |  |
4CA | Coal Mine Reclamation Balance Sheet Obligations |  |  |  |  |  |  |  |
Fuel and Purchased Power Commitments and Purchase Obligations [Abstract] |  |  |  |  |  |  |  |
Total obligation |  |  |  |  | 15,000,000 |  |  |
Breach of Contract for Disposal of Spent Nuclear Fuel and/or High Level Radioactive Waste |  |  |  |  |  |  |  |
Palo Verde Nuclear Generating Station [Abstract] |  |  |  |  |  |  |  |
Litigation settlement, amount |  |  | $ 57,400,000 |  |  |  |  |
Breach of Contract for Disposal of Spent Nuclear Fuel and/or High Level Radioactive Waste | ARIZONA PUBLIC SERVICE COMPANY |  |  |  |  |  |  |  |
Palo Verde Nuclear Generating Station [Abstract] |  |  |  |  |  |  |  |
Litigation settlement, amount |  |  | $ 16,700,000 |  |  |  |  |
Arizona Public Service Company and Palo Verde Owners vs. United States Department of Energy - Spent Nuclear Fuel and Waste Disposal |  |  |  |  |  |  |  |
Palo Verde Nuclear Generating Station [Abstract] |  |  |  |  |  |  |  |
Proceeds from legal settlements |  |  |  |  | $ 53,900,000 |  |  |
Arizona Public Service Company and Palo Verde Owners vs. United States Department of Energy - Spent Nuclear Fuel and Waste Disposal | ARIZONA PUBLIC SERVICE COMPANY |  |  |  |  |  |  |  |
Palo Verde Nuclear Generating Station [Abstract] |  |  |  |  |  |  |  |
New claims filed | claim |  |  |  |  | 2 |  |  |
Number of settlement agreement time periods | time_period |  |  |  |  | 2 |  |  |
Proceeds from legal settlements |  |  |  |  | $ 15,700,000 |  |  |
Subsequent Event | ARIZONA PUBLIC SERVICE COMPANY |  |  |  |  |  |  |  |
Palo Verde Nuclear Generating Station [Abstract] |  |  |  |  |  |  |  |
Maximum available nuclear liability insurance |  | $ 450,000,000 |  |  |  |  |  |
Remaining nuclear liability insurance through mandatory industry wide retrospective assessment program |  | $ 13,000,000,000 |  |  |  |  |  |
Subsequent Event | Arizona Public Service Company and Palo Verde Owners vs. United States Department of Energy - Spent Nuclear Fuel and Waste Disposal |  |  |  |  |  |  |  |
Palo Verde Nuclear Generating Station [Abstract] |  |  |  |  |  |  |  |
Litigation settlement, amount | $ 11,300,000 |  |  |  |  |  |  |
Subsequent Event | Arizona Public Service Company and Palo Verde Owners vs. United States Department of Energy - Spent Nuclear Fuel and Waste Disposal | ARIZONA PUBLIC SERVICE COMPANY |  |  |  |  |  |  |  |
Palo Verde Nuclear Generating Station [Abstract] |  |  |  |  |  |  |  |
Litigation settlement, amount | $ 3,300,000 |  |  |  |  |  |  |

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