Regulatory Matters - Retail Rate Case Filing (Details) - Retail Rate Case Filing with Arizona Corporation Commission - ACC - APS - USD ($) $ in Millions	Jun. 01, 2016	Dec. 31, 2015	Jun. 01, 2011
Public Utilities, General Disclosures [Line Items]
Net retail rate increase	$ 165.9		$ 95.5
Adjustor account balance transferred into base rates, amount		$ 267.6
Approximate percentage of increase in average customer bill	5.74%
Approximate percentage of increase in average residential customer bill	7.96%

Public Utilities, Adjustor Account Balance Transferred into Base Rates, Amount

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Rate Matter, Approximate Percentage of Increase in Average Customer Bill

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Rate Matter, Approximate Percentage of Increase in Average Residential Customer Bill

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Amount of public utility's requested rate increase (decrease) with regulatory agency.

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