| **Regulatory Matters - Narrative (Details) Customer in Thousands**                                                     |              |               |        |                 |              |               |        |                   |              |            |              |                |        |        |              |            |               |              |          | 12 Months Ended |                |        |        |              |        |              |              |
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| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Ballot initiative, proposed required energy supply to be obtained from renewable sources (as a percent)                |         |          |   |            |         |          |   |              |         |       |         |           |   | 50.00% |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Number of customers | Customer                                                                                         |         |          | 13     |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Inconvenience payment                                                                                                  |         |          | $ 25   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| ARIZONA PUBLIC SERVICE COMPANY | Lost Fixed Cost Recovery Mechanism                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Fixed cost recoverable per residential power lost (in dollars per kWh) | $ / kWh                                       |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   | 0.031  |         |   |         |         |   |   |   |
| Fixed costs recoverable per residential power lost (in dollars per kWh) | $ / kWh                                      |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   | 0.023  |         |   |         |         |   |   |   |
| Fixed costs recoverable per power lost (in dollars per kWh) | $ / kWh                                                  |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           | 0.025  |   |         |   |         |         |   |   |   |
| Rate matter cap percentage of retail revenue                                                                           |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            | 1.00%          |   |   |         |   |         |         |   |   |   |
| Amount of adjustment approved representing prorated sales losses pending approval                                      |         |          |   |            |         |          |   |              | $ 36,200,000 |       |         |           |   |   | $ 60,700,000 |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Decrease in amount of adjustment representing prorated sales losses                                                    |         |          |   |            |         |          |   |              | $ 24,500,000 |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| ARIZONA PUBLIC SERVICE COMPANY | ACC                                                                                   |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Requested rate decrease for tax act                                                                                    |         |          |   | $ (184,000,000) |         |          |   |              |         |       | $ 86,500,000 |           |   |   |         |       | $ 119,100,000 |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Requested rate increase (decrease), deferred taxes amortization, period                                                |         |          |   |            |         |          |   | 28 years 6 months |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Requested rate increase (decrease), amount, one-time bill credit                                                       |         |          |   |            | $ 64,000,000 |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Requested rate increase (decrease), amount, one-time bill credit, additional benefit                                   |         |          |   |            | $ 39,500,000 |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Regulatory impact, operating results                                                                                   |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            | $ (10,000,000) |   |   |         |   |         |         |   |   |   |
| ARIZONA PUBLIC SERVICE COMPANY | ACC | Arizona Renewable Energy Standard and Tariff 2018                               |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Amount of proposed budget                                                                                              |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   | $ 86,300,000 |   |         | $ 89,900,000 |   |   | $ 90,000,000 |
| ARIZONA PUBLIC SERVICE COMPANY | ACC | Demand Side Management Adjustor Charge 2018                                     |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Amount of proposed budget                                                                                              |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            | 51,900,000     |   |   |         |   | $ 34,100,000 |         | $ 52,600,000 | $ 52,600,000 |   |
| ARIZONA PUBLIC SERVICE COMPANY | ACC | Power Supply Adjustor (PSA)                                                     |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Fuel And purchased power costs, excess annual limit                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            | $ 16,400,000   |   |   |         |   |         |         |   |   |   |
| Maximum increase decrease in PSA rate (in dollars per kWh) | $ / kWh                                                   |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         | 0.004      |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| PSA rate (in dollars per kWh) | $ / kWh                                                                                |         |          |   |            |         |          |   |              |         | (0.001658) |         |           |   |   |         | (0.004555) |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Forward component of PSA rate (in dollars per kWh) | $ / kWh                                                           |         |          |   |            |         |          |   |              |         | (0.000536) |         |           |   |   |         | (0.002009) |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Historical component of PSA rate (in dollars per kWh) | $ / kWh                                                        |         |          |   |            |         |          |   |              |         | 0.001122   |         |           |   |   |         | 0.002546   |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| ARIZONA PUBLIC SERVICE COMPANY | ACC | Net Metering                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Cost of service, resource comparison proxy method, maximum annual percentage decrease                                  |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         | 10.00%   |            |           |   |   |         |   |         |         |   |   |   |
| Cost of service for interconnected DG system customers, grandfathered period                                           |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         | 20 years |            |           |   |   |         |   |         |         |   |   |   |
| Guaranteed export price period                                                                                         |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         | 10 years |            |           |   |   |         |   |         |         |   |   |   |
| Settlement agreement, energy price for exported energy (in dollars per kWh) | $ / kWh                                  |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         | 0.129    |            |           |   |   |         |   |         |         |   |   |   |
| Request second-year energy price for exported energy | $ / kWh                                                         |         |          |   |            |         |          | 0.105  |              |         |       |         |           | 0.116  |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| ARIZONA PUBLIC SERVICE COMPANY | FERC | Transmission rates, transmission cost adjustor and other transmission matters  |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Rate matters, increase (decrease) in cost recovery                                                                     |         |          |   |            |         | $ (4,900,000) |   |              |         |       |         | $ (22,700,000) |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Cost Recovery Mechanisms | ARIZONA PUBLIC SERVICE COMPANY | ACC | Power Supply Adjustor (PSA)                          |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| PSA rate in prior years (in dollars per kWh) | $ / kWh                                                                 |         |          |   |            |         |          |   |              |         | (0.002897) |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Number of agreements | agreement                                                                                       |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         | 2      |         |         |   |   |   |
| Solar Communities | ARIZONA PUBLIC SERVICE COMPANY | ACC | Arizona Renewable Energy Standard and Tariff 2018           |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Program term                                                                                                           |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          | 3 years      |     |            |           |   |   |         |   |         |         |   |   |   |
| Minimum | ARIZONA PUBLIC SERVICE COMPANY | ACC                                                                         |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Regulatory impact, operating results                                                                                   |         |          |   | $ 69,000,000    |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Minimum | Solar Communities | ARIZONA PUBLIC SERVICE COMPANY | ACC | Arizona Renewable Energy Standard and Tariff 2018 |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Required annual capital investment                                                                                     |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          | $ 10,000,000 |     |            |           |   |   |         |   |         |         |   |   |   |
| Maximum | Solar Communities | ARIZONA PUBLIC SERVICE COMPANY | ACC | Arizona Renewable Energy Standard and Tariff 2018 |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Required annual capital investment                                                                                     |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          | $ 15,000,000 |     |            |           |   |   |         |   |         |         |   |   |   |
| Subsequent Event | ARIZONA PUBLIC SERVICE COMPANY | Lost Fixed Cost Recovery Mechanism                                 |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Amount of adjustment approved representing prorated sales losses pending approval                                      | $ 26,600,000 |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Decrease in amount of adjustment representing prorated sales losses                                                    | $ 9,600,000  |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Subsequent Event | ARIZONA PUBLIC SERVICE COMPANY | ACC | Power Supply Adjustor (PSA)                                  |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| PSA rate (in dollars per kWh) | $ / kWh                                                                                |         | 0.000456      |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Forward component of PSA rate (in dollars per kWh) | $ / kWh                                                           |         | 0.002086      |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Historical component of PSA rate (in dollars per kWh) | $ / kWh                                                        |         | 0.001630      |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Subsequent Event | ARIZONA PUBLIC SERVICE COMPANY | FERC | Environmental Improvement Surcharge                         |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Rate matters, increase (decrease) in cost recovery                                                                     |         | $ (8,750,000) |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Subsequent Event | Cost Recovery Mechanisms | ARIZONA PUBLIC SERVICE COMPANY | ACC | Power Supply Adjustor (PSA)       |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Maximum increase decrease in PSA rate (in dollars per kWh) | $ / kWh                                                   |         | 0.004         |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| PSA rate in prior years (in dollars per kWh) | $ / kWh                                                                 |         | (0.002115)    |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Forecast | ARIZONA PUBLIC SERVICE COMPANY | FERC | Environmental Improvement Surcharge                                 |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| **Regulatory Matters [Line Items]**                                                                                    |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     |            |           |   |   |         |   |         |         |   |   |   |
| Rate matters, increase (decrease) in cost recovery, excess of annual amount                                            |         |          |   |            |         |          |   |              |         |       |         |           |   |   |         |       |          |         |     | $ (2,000,000.0) |           |   |   |         |   |         |         |   |   |   |

| X                                                                                                                                                                                                                                                                                                                             |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of Adjustment Representing Prorated Sales Losses Pending Approval
+ References
No definition available.
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| X                                                                                                                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Cost Recovery, Number Of Agreements
+ References
No definition available.
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| - Definition
Forward Component of PSA Rate1
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                  |
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| - Definition
Fuel And Purchased Power Costs, Excess Annual Limit
+ References
No definition available.
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| X                                                                                                                                                                                                                                                   |
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| - Definition
Historical Component of PSA Rate1
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                      |
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| - Definition
Increase (Decrease) in Amount of Adjustment Representing Prorated Sales Losses
+ References
No definition available.
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| X                                                                                                                                                                                                                                                            |
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| - Definition
Maximum Increase Decrease in PSA Rate1
+ References
No definition available.
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| - Definition
PSA Rate1
+ References
No definition available.
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| X                                                                                                                                                                                                                                 |
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| - Definition
PSA Rate In Prior Years1
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                         |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Public Utilities, Ballot Initiative, Proposed Required Energy Supply From Renewable Sources, Percent
+ References
No definition available.
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| - Definition
Public Utilities, Program Term
+ References
No definition available.
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| - Definition
Public Utilities, Requested Rate Increase (Decrease), Amount, One-time Bill Credit
+ References
No definition available.
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| X                                                                                                                                                                                                                                                                                                                                                                               |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Public Utilities, Requested Rate Increase (Decrease), Amount, One-time Bill Credit, Additional Benefit
+ References
No definition available.
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Public Utilities, Requested Rate Increase (Decrease), Amount, Tax Cuts and Jobs Act of 2017, Incomplete Accounting, Provisional Income Tax Expense (Benefit)
+ References
No definition available.
+ Details**Name:**pnw_PublicUtilitiesRequestedRateIncreaseDecreaseAmountTaxCutsandJobsActof2017IncompleteAccountingProvisionalIncomeTaxExpenseBenefit**Namespace Prefix:**pnw_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                      |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Public Utilities, Requested Rate Increase (Decrease), Deferred Taxes Amortization, Period
+ References
No definition available.
+ Details**Name:**pnw_PublicUtilitiesRequestedRateIncreaseDecreaseDeferredTaxesAmortizationPeriod**Namespace Prefix:**pnw_**Data Type:**xbrli:durationItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                       |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Public Utilities, Required Annual Capital Investment
+ References
No definition available.
+ Details**Name:**pnw_PublicUtilitiesRequiredAnnualCapitalInvestment**Namespace Prefix:**pnw_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                           |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents information pertaining to cap percentage of retail revenues.
+ References
No definition available.
+ Details**Name:**pnw_RateMatterCapPercentageOfRetailRevenue**Namespace Prefix:**pnw_**Data Type:**num:percentItemType**Balance Type:**na**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                                 |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Rate Matter, Fixed Cost Recoverable Per Non Residential Power Lost1
+ References
No definition available.
+ Details**Name:**pnw_RateMatterFixedCostRecoverablePerNonResidentialPowerLost1**Namespace Prefix:**pnw_**Data Type:**srt-types:perUnitItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                   |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Rate Matter, Fixed Cost Recoverable Per Power Lost1
+ References
No definition available.
+ Details**Name:**pnw_RateMatterFixedCostRecoverablePerPowerLost1**Namespace Prefix:**pnw_**Data Type:**srt-types:perUnitItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                          |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Rate Matter, Fixed Cost Recoverable Per Residential Power Lost1
+ References
No definition available.
+ Details**Name:**pnw_RateMatterFixedCostRecoverablePerResidentialPowerLost1**Namespace Prefix:**pnw_**Data Type:**srt-types:perUnitItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Represents the amount of proposed budget.
+ References
No definition available.
+ Details**Name:**pnw_RateMatterProposedBudget**Namespace Prefix:**pnw_**Data Type:**xbrli:monetaryItemType**Balance Type:**debit**Period Type:**instant |
| X                                                                                                                                                                                                                                                                                                               |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Rate Matter, Request Second-Year Energy Price for Exported Energy1
+ References
No definition available.
+ Details**Name:**pnw_RateMatterRequestSecondYearEnergyPriceforExportedEnergy1**Namespace Prefix:**pnw_**Data Type:**srt-types:perUnitItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                   |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Rate Matter, Settlement Agreement, Energy Price for Exported Energy1
+ References
No definition available.
+ Details**Name:**pnw_RateMatterSettlementAgreementEnergyPriceforExportedEnergy1**Namespace Prefix:**pnw_**Data Type:**srt-types:perUnitItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                                      |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Rate Matters, Cost of Service, Resource Comparison Proxy Method, Maximum Annual Percentage Decrease
+ References
No definition available.
+ Details**Name:**pnw_RateMattersCostofServiceResourceComparisonProxyMethodMaximumAnnualPercentageDecrease**Namespace Prefix:**pnw_**Data Type:**num:percentItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                                         |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Rate Matters, Cost of Service for Interconnected DG System Customers, Grandfathered Period
+ References
No definition available.
+ Details**Name:**pnw_RateMattersCostofServiceforInterconnectedDGSystemCustomersGrandfatheredPeriod**Namespace Prefix:**pnw_**Data Type:**xbrli:durationItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                                   |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Rate Matters, Cost of Service for New Customers, Guaranteed Export Price Period
+ References
No definition available.
+ Details**Name:**pnw_RateMattersCostofServiceforNewCustomersGuaranteedExportPricePeriod**Namespace Prefix:**pnw_**Data Type:**xbrli:durationItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Rate Matters, Increase (Decrease) in Cost Recovery
+ References
No definition available.
+ Details**Name:**pnw_RateMattersIncreaseDecreaseinCostRecovery**Namespace Prefix:**pnw_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                                                              |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Rate Matters, Increase (Decrease) in Cost Recovery, Excess Of Annual Amount
+ References
No definition available.
+ Details**Name:**pnw_RateMattersIncreaseDecreaseinCostRecoveryExcessOfAnnualAmount**Namespace Prefix:**pnw_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                                |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Rate Plan Comparison Tool, Inconvenience Payment
+ References
No definition available.
+ Details**Name:**pnw_RatePlanComparisonToolInconveniencePayment**Namespace Prefix:**pnw_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Rate Plan Comparison Tool, Number Of Customers
+ References
No definition available.
+ Details**Name:**pnw_RatePlanComparisonToolNumberOfCustomers**Namespace Prefix:**pnw_**Data Type:**xbrli:integerItemType**Balance Type:**na**Period Type:**instant |
| X                                                                                                                                                                                                                                                          |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Regulatory Impact, Operating Results
+ References
No definition available.
+ Details**Name:**pnw_RegulatoryImpactOperatingResults**Namespace Prefix:**pnw_**Data Type:**xbrli:monetaryItemType**Balance Type:**credit**Period Type:**duration |
| X                                                                                                                                                                                            |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - References
No definition available.
+ Details**Name:**pnw_RegulatoryMattersLineItems**Namespace Prefix:**pnw_**Data Type:**xbrli:stringItemType**Balance Type:**na**Period Type:**duration |
| X                                                                                                                                                 |
|---------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**dei_LegalEntityAxis=pnw_ArizonaPublicServiceCompanyMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                 |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_PublicUtilitiesRegulatoryProceedingAxis=pnw_LostFixedCostRecoveryMechanismsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                           |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_RegulatoryAgencyAxis=pnw_ArizonaCorporationCommissionMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                             |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_PublicUtilitiesRegulatoryProceedingAxis=pnw_ArizonaRenewableEnergyStandardandTariff2018Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                        |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_PublicUtilitiesRegulatoryProceedingAxis=pnw_DemandSideManagementAdjustorCharge2018Member**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_PublicUtilitiesRegulatoryProceedingAxis=pnw_PowerSupplyAdjustorMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                             |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_PublicUtilitiesRegulatoryProceedingAxis=pnw_NetMeteringMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                            |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_RegulatoryAgencyAxis=pnw_UnitedStatesFederalEnergyRegulatoryCommissionMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                              |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_PublicUtilitiesRegulatoryProceedingAxis=pnw_OpenAccessTransmissionTariffMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                           |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**pnw_PublicUtilitiesRegulatoryRegulatoryMattersAxis=pnw_CostRecoveryMechanismsMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                               |
|-------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**pnw_PublicUtilityProgramAxis=pnw_SolarCommunitiesMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**srt_RangeAxis=srt_MinimumMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                       |
|-------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**srt_RangeAxis=srt_MaximumMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                     |
|-------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                                                                   |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**us-gaap_PublicUtilitiesRegulatoryProceedingAxis=pnw_EnvironmentalImprovementSurchargeMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |
| X                                                                                                                                            |
|----------------------------------------------------------------------------------------------------------------------------------------------|
| - Details**Name:**srt_StatementScenarioAxis=srt_ScenarioForecastMember**Namespace Prefix:****Data Type:**na**Balance Type:****Period Type:** |