| **Long-Term Debt and Liquidity Matters - Narrative (Details)**                                                       |             |              |               |               | 3 Months Ended |               |                 |               |               |
|----------------------------------------------------------------------------------------------------------------------|-------------|--------------|---------------|---------------|----------------|---------------|-----------------|---------------|---------------|
||
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Issuance of long-term debt                                                                                           |        |         |          |          | $ 312,052,000  | $ 150,000,000 |            |          |          |   |
| Pinnacle West | Term Loan                                                                                            |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Debt instrument, face amount                                                                                         |        |         |          |          |           |          |            |          | $ 150,000,000 |   |
| Pinnacle West | Term Loan | Term Loan Maturing 2021                                                                  |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Debt instrument, face amount                                                                                         |        |         |          | $ 450,000,000 |           |          |            |          |          |   |
| Issuance of long-term debt                                                                                           |        |         | $ 300,000,000 | $ 150,000,000 |           |          |            |          |          |   |
| Pinnacle West | Revolving Credit Facility | Revolving Credit Facility Maturing May 2026                              |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Current borrowing capacity on credit facility                                                                        |        |         |          |          | 200,000,000    |          |            | $ 200,000,000 |          |   |
| Maximum borrowing capacity on credit facility upon satisfaction of certain conditions and consent of lenders (up to) |        |         |          |          |           |          |            | $ 300,000,000 |          |   |
| Long-term line of credit                                                                                             |        |         |          |          | 0              |          |            |          |          |   |
| Pinnacle West | Letter of Credit | Revolving Credit Facility Maturing May 2026                                       |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Outstanding letters of credit                                                                                        |        |         |          |          | 0              |          |            |          |          |   |
| Pinnacle West | Commercial paper | Revolving Credit Facility Maturing May 2026                                       |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Commercial paper                                                                                                     |        |         |          |          | 13,000,000     |          |            |          |          |   |
| APS                                                                                                                  |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Percentage of capitalization                                                                                         |        |         |          |          |           |          |            |          |          | 7.00% |
| Capacity available for trade purchases                                                                               |        |         |          |          |           |          |            |          |          | $ 500,000,000 |
| Long-term debt limit                                                                                                 |        |         |          |          |           |          |            |          |          | $ 7,500,000,000 |
| Equity infusion from Pinnacle West                                                                                   |        |         | $ 150,000,000 |          | 150,000,000    |          |            |          |          |   |
| APS | Subsequent Event                                                                                               |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Long-term debt limit                                                                                                 |        |         |          |          |           |          | $ 8,000,000,000 |          |          |   |
| APS | Revolving Credit Facility | Revolving Credit Facility Maturing May 2026                                        |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Current borrowing capacity on credit facility                                                                        |        |         |          |          | 1,000,000,000  |          |            |          |          |   |
| Maximum borrowing capacity on credit facility upon satisfaction of certain conditions and consent of lenders (up to) |        |         |          |          | 1,400,000,000  |          |            |          |          |   |
| APS | Revolving Credit Facility | Revolving Credit Facility Maturing May 2026, Facility One                          |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Current borrowing capacity on credit facility                                                                        |        |         |          |          | 500,000,000    |          |            |          |          |   |
| Maximum borrowing capacity on credit facility upon satisfaction of certain conditions and consent of lenders (up to) |        |         |          |          | 700,000,000    |          |            |          |          |   |
| APS | Revolving Credit Facility | Revolving Credit Facility Maturing May 2026, Facility Two                          |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Current borrowing capacity on credit facility                                                                        |        |         |          |          | 500,000,000    |          |            |          |          |   |
| Maximum borrowing capacity on credit facility upon satisfaction of certain conditions and consent of lenders (up to) |        |         |          |          | 700,000,000    |          |            |          |          |   |
| APS | Revolving Credit Facility | Revolving Credit Facility Maturing in 2022 and 2023                                |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Long-term line of credit                                                                                             |        |         |          |          | $ 0            |          |            |          |          |   |
| Number of line of credit facilities | creditFacility                                                                 |        |         |          |          | 2              |          |            |          |          |   |
| APS | Letter of Credit | Revolving Credit Facility Maturing May 2026                                                 |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Outstanding letters of credit                                                                                        |        |         |          |          | $ 0            |          |            |          |          |   |
| APS | Commercial paper                                                                                               |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Maximum commercial paper support available under credit facility                                                     |        |         |          |          | 750,000,000    |          |            |          |          |   |
| APS | Commercial paper | Revolving Credit Facility Maturing May 2026                                                 |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Commercial paper                                                                                                     |        |         |          |          | 250,000,000    |          |            |          |          |   |
| BCE                                                                                                                  |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Solar and battery storage capacity (in MW) | MW                                                                      |        | 31           |          |          |           |          |            |          |          |   |
| BCE | Term Loan | Non-Recourse Construction Term Loan Facility                                                       |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Debt instrument, face amount                                                                                         |        | $ 42,000,000 |          |          |           |          |            |          |          |   |
| BCE | Letter of Credit                                                                                               |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Debt instrument, face amount                                                                                         |        | 5,000,000    |          |          |           |          |            |          |          |   |
| BCE | Bridge Loan | Equity Bridge Loan Facility                                                                      |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Debt instrument, face amount                                                                                         |        | $ 33,000,000 |          |          |           |          |            |          |          |   |
| Issuance of long-term debt                                                                                           |        |         |          |          | $ 12,000,000   |          |            |          |          |   |
| BCE | Bridge Loan | Equity Bridge Loan Facility | Subsequent Event                                                   |        |         |          |          |           |          |            |          |          |   |
| **Long-Term Debt and Liquidity Matters**                                                                             |        |         |          |          |           |          |            |          |          |   |
| Issuance of long-term debt                                                                                           | $ 7,000,000 |         |          |          |           |          |            |          |          |   |

| X                                                                                                                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
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Adjustments to Additional Paid in Capital, Contributions from Parent
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| - Definition
Represents the maximum borrowings available for the commercial paper program under the terms of line of credit facility.
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No definition available.
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Represents the number of line of credit facilities.
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Public Utilities, Solar and Battery Storage Capacity
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Regulatory Matters, Long-term Debt Limit
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Regulatory Matters, Long-term Debt, Percentage Of Capitalization
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| - Definition
Carrying value as of the balance sheet date of short-term borrowings using unsecured obligations issued by banks, corporations and other borrowers to investors. The maturities of these money market securities generally do not exceed 270 days.
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Face (par) amount of debt instrument at time of issuance.
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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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No definition available.
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| - Definition
The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.
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No definition available.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.
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| - Definition
The maximum amount of borrowing capacity under a line of credit that is available as of the balance sheet date for financing purchases of goods acquired for inventory or imminent delivery to a customer.
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No definition available.
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| - Definition
Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.
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| - Definition
Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.
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| - Definition
The cash inflow from a debt initially having maturity due after one year or beyond the operating cycle, if longer.
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