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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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No definition available.

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The common equity ratio (defined as the total shareholder equity divided by the sum of total shareholder equity and long-term debt, including current maturities of long-term debt), which the entity is required to maintain pursuant to an order from a regulatory authority.

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No definition available.

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The amount of total shareholder equity required in order for the entity to pay dividends pursuant to an order from a regulatory authority.

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No definition available.

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The sum of total shareholder equity and long-term debt less current maturities, including a portion of APS' current maturities of long-term debt.

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No definition available.

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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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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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No definition available.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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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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Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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No definition available.

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Gross amount of debt extinguished.

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No definition available.

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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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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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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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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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Reflects the total carrying amount as of the balance sheet date of debt having initial terms less than one year or the normal operating cycle, if longer.

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Total of all stockholders' equity (deficit) items, net of receivables from officers, directors, owners, and affiliates of the entity which are attributable to the parent. The amount of the economic entity's stockholders' equity attributable to the parent excludes the amount of stockholders' equity which is allocable to that ownership interest in subsidiary equity which is not attributable to the parent (noncontrolling interest, minority interest). This excludes temporary equity and is sometimes called permanent equity.

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Long-Term Debt and Liquidity Matters - Narrative (Details)	Jun. 28, 2018 USD ($)	Jun. 27, 2018	Jun. 26, 2018 USD ($)	May 30, 2018 USD ($)	Sep. 30, 2018 USD ($) Facility	Aug. 09, 2018 USD ($)	Jul. 12, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jul. 31, 2017 USD ($)
Long-Term Debt and Liquidity Matters
Shot-term debt					$ 128,200,000			$ 95,400,000
Debt Provisions
Total shareholder equity					5,353,572,000			5,006,690,000
Pinnacle West \| Revolving Credit Facility \| Revolving credit facility maturing July 2018
Long-Term Debt and Liquidity Matters
Debt instrument, term		364 days
Maximum borrowing capacity on credit facility upon satisfaction of certain conditions and consent of lenders (up to)									$ 125,000,000
Pinnacle West \| Revolving Credit Facility \| Revolving credit facility maturing June 2019
Long-Term Debt and Liquidity Matters
Debt instrument, term			364 days
Maximum borrowing capacity on credit facility upon satisfaction of certain conditions and consent of lenders (up to)	$ 150,000,000
Shot-term debt					79,000,000
Pinnacle West \| Revolving Credit Facility \| Revolving Credit Facility Maturing May 2021
Long-Term Debt and Liquidity Matters
Current borrowing capacity on credit facility							$ 200,000,000
Pinnacle West \| Revolving Credit Facility \| Revolving credit Facility maturing July 2023
Long-Term Debt and Liquidity Matters
Maximum borrowing capacity on credit facility upon satisfaction of certain conditions and consent of lenders (up to)							300,000,000
Current borrowing capacity on credit facility							200,000,000
Long-term line of credit					0
Pinnacle West \| Letter of Credit \| Revolving credit Facility maturing July 2023
Long-Term Debt and Liquidity Matters
Outstanding letters of credit					0
Pinnacle West \| Commercial paper \| Revolving credit Facility maturing July 2023
Long-Term Debt and Liquidity Matters
Commercial paper					49,000,000
APS
Long-Term Debt and Liquidity Matters
Extinguishment of debt				$ 32,000,000
Debt Provisions
Total shareholder equity					5,625,282,000			$ 5,256,829,000
APS \| ACC
Debt Provisions
Total shareholder equity					5,600,000,000
Total capitalization					10,600,000,000
Dividend restrictions, shareholder equity required					$ 4,200,000,000
APS \| ACC \| Minimum
Debt Provisions
Required common equity ratio ordered by ACC (as a percent) (at least)					40.00%
APS \| Senior notes
Long-Term Debt and Liquidity Matters
Debt instrument, face amount						$ 300,000,000
Debt instrument, interest rate						4.20%
APS \| Revolving Credit Facility \| Revolving Credit Facility Maturing May 2021
Long-Term Debt and Liquidity Matters
Current borrowing capacity on credit facility					$ 500,000,000
APS \| Revolving Credit Facility \| Revolving credit Facility maturing July 2023
Long-Term Debt and Liquidity Matters
Maximum borrowing capacity on credit facility upon satisfaction of certain conditions and consent of lenders (up to)					700,000,000
Current borrowing capacity on credit facility					500,000,000		$ 500,000,000
APS \| Revolving Credit Facility \| Revolving Credit Facility Maturing in 2022 and 2023
Long-Term Debt and Liquidity Matters
Maximum borrowing capacity on credit facility upon satisfaction of certain conditions and consent of lenders (up to)					1,400,000,000
Current borrowing capacity on credit facility					1,000,000,000
Long-term line of credit					$ 0
Number of line of credit facilities \| Facility					2
APS \| Revolving Credit Facility \| Term Loan Facility
Long-Term Debt and Liquidity Matters
Extinguishment of debt			$ 50,000,000
APS \| Revolving Credit Facility \| Revolving credit facility maturing June 2022
Long-Term Debt and Liquidity Matters
Maximum borrowing capacity on credit facility upon satisfaction of certain conditions and consent of lenders (up to)					$ 700,000,000
Current borrowing capacity on credit facility					500,000,000
APS \| Commercial paper
Long-Term Debt and Liquidity Matters
Maximum commercial paper support available under credit facility					500,000,000
APS \| Commercial paper \| Revolving Credit Facility Maturing in 2022 and 2023
Long-Term Debt and Liquidity Matters
Commercial paper					$ 0
LIBOR \| Pinnacle West \| Revolving Credit Facility \| Revolving credit facility maturing June 2019
Long-Term Debt and Liquidity Matters
Debt instrument, basis spread on variable rate	0.70%