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Commitments and Contingencies - Superfund-Related Matters, Southwest Power Outage and Clean Air Act (Details) $ in Millions |  |  |  | 6 Months Ended
--- | --- | --- | --- | ---
Jun. 24, 2015 USD ($) power_plant | Aug. 06, 2013 Defendant | Sep. 08, 2011 kV Customer | Jun. 30, 2015 USD ($)
Arizona Public Service Company |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Capacity of transmission line that tripped out of service (in kV) | kV |  |  | 500 |
Period, after the transmission line went off-line, over which generation and transmission resources for the Yuma area were lost |  |  | 10 minutes |
Number of customers losing service in Yuma area | Customer |  |  | 69,700 |
Arizona Public Service Company | Contaminated groundwater wells |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Costs related to investigation and study under Superfund site |  |  |  | $ 2.0
Number of defendants against whom Roosevelt Irrigation District (RID) filed lawsuit | Defendant |  | 24 |  |
Arizona Public Service Company | Clean Air Act Citizen Lawsuit |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Public comment period | 30 days |  |  |
Number of power plants in lawsuit | power_plant | 2 |  |  |
Litigation settlement percent | 15.00% |  |  |
Four Corners | Clean Air Act Citizen Lawsuit |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Civil penalty amount | $ 1.5 |  |  |
Environmental mitigation project cost | $ 6.2 |  |  |

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- Definition Costs related to site-wide groundwater remedial investigation and feasibility study work plan because subsidiary has been found to be potentially responsible parties ("PRPs") with liability for cleanup of hazardous substances that contaminates the soil, water or air, under the Comprehensive Environmental Response, Compensation and Liability Act ("Superfund"). + References No definition available. + Details
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