New revolving credit facility maturing in 2019 Represents the credit facility maturing in May 2019. Line of Credit Maturing in 2019 [Member] Line of Credit Maturing in May 2019 [Member] Revolving credit facility maturing in 2019 Represents the revolving credit facility maturing in May 2019. Pollution Control Revenue Refunding Bonds 2009 Series A, Series B and Series C [Member] Pollution Control Revenue Refunding Bonds, 2009 Series A, B and C A contractual arrangement to borrow and repay an amount under Pollution Control Revenue Refunding Bonds, 2009 series A, B and C. Unsecured Senior Notes 3.35 Percent Mature on 15 June, 2024 [Member] 3.35% unsecured senior note A contractual arrangement to borrow and repay an amount under unsecured senior notes at an interest rate of 3.35 percent, maturing on June 15, 2024. Unsecured Senior Notes 5.80 Percent Mature on 30 June, 2014 [Member] 5.80% senior notes A contractual arrangement to borrow and repay an amount under unsecured senior notes at an interest rate of 5.80percent, maturing on June 30, 2014. Defined Benefit Plan Estimated Future Employer Contributions in Year Two 2015 Amount of employer's best estimate of contributions expected to be paid to the plan during the second fiscal year beginning after the date of the latest statement of financial position. Defined Benefit Plan, Health Care Cost Trend Rates Assumed for Next Fiscal Year Initial healthcare cost trend rate (as a percent) The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status. change values to 0.0750 for 2011; 0.0800 for 2010; remove value for 2009. Defined Benefit Plan Period after which Rate Reaches Ultimate Trend Rate Number of years to ultimate trend rate The period after which the ultimate health care cost trend rate is expected to be reached. Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost Expected Long Term Return on Assets for Next Fiscal Year Expected long-term return on plan assets for next fiscal year (as a percent) An assumption as to the rate of return on plan assets reflecting the average rate of earnings expected on the funds invested or to be invested to provide for the benefits included in the benefit obligation during next fiscal year. ANPP 500kV System [Member] Represents ANPP 500KV System, a jointly-owned transmission facility of the entity. ANPP 500kV System Represents APS Energy Services Company, Inc. (APSES), a subsidiary of Pinnacle West dealing with energy-related projects. APSES APS Energy Services Company Inc [Member] Amendment Flag Accumulated Amortization on Nuclear Fuel Accumulated amortization on nuclear fuel Represents the accumulated amortization on nuclear fuel. Accumulated amortization on nuclear fuel Represents the tax component of accumulated other comprehensive income (loss) of defined benefit pension and other postretirement plans. Accumulated Other Comprehensive Income (Loss), Defined Benefit Pension and Other Postretirement Plans Tax Income tax benefit Advances of Loans to Subsidiaries Advances of loans to subsidiaries Represents the cash outflow associated with the advances of loans to subsidiaries. All Risk Insurance for Property Damage and Decontamination at Palo Verde Amount of "all risk" (including nuclear hazards) insurance for property damage to, and decontamination of, property at Palo Verde Represents the "all risk" (including nuclear hazards) insurance for property damage to, and decontamination of, property at Palo Verde of which a substantial portion must first be applied to stabilization and decontamination. Alternative Investments [Member] Alternative investments Represents information pertaining to alternative investments. Amortization to Income [Abstract] Amortization to income: Amount of Adjustment Representing Prorated Sales Losses Approved Amount of adjustment approved representing prorated sales losses Represents the amount of adjustment approved representing prorated sales losses on the first LFCR adjustment filing. Represents the annual limit per incident with respect to the maximum assessment per reactor under the program for each nuclear incident, to be periodically adjusted for inflation. Annual Limit Per Incident with Respect to Maximum Assessment Annual limit per incident with respect to maximum retrospective premium assessment Annual payment limitation with respect to maximum potential retrospective premium assessment Represents the annual payment limitation with respect to maximum potential retrospective assessment. Annual Payment Limitation with Respect to Maximum Potential Retrospective Assessment ACC Represents the Arizona Corporation Commission (ACC), which regulates public utilities in Arizona. Arizona Corporation Commission [Member] ARIZONA PUBLIC SERVICE COMPANY Arizona Public Service Company [Member] APS Represents Arizona Public Service Company, which is an electric utility subsidiary of the entity. 2012 RES Represents the RES program which permits a surcharge for 2012 as part of customer bills to recover approved amounts for use in renewable energy projects. Arizona Renewable Energy Standard and Tariff 2012 [Member] Arizona Renewable Energy Standard and Tariff [Member] RES Represents the RES program which permits a surcharge as part of customer bills to recover approved amounts for use in renewable energy projects. Arizona Renewable Energy Standard and Tariff 2013 [Member] 2013 RES Represents the RES program which permits a surcharge for 2013 as part of customer bills to recover approved amounts for use in renewable energy projects. Asset Retirement Obligations [Line Items] Asset Retirement Obligations Cash paid (received) during the period for: Cash paid during the period for: Cash Paid During Period [Abstract] Current Fiscal Year End Date Change in margin and collateral accounts - liabilities Change in Margin and Collateral Accounts Liabilities The aggregate net change during the reporting period in moneys received as security, collateral, or margin deposits. Change in margin and collateral accounts - liabilities Debt Instrument Number of Tax Exempt Indebtedness Series Reacquired Number of tax-exempt indebtedness series re-acquired Represents the number of tax-exempt indebtedness series re-acquired. Represents Cholla common facilities, a jointly-owned generating facility of the entity. Cholla common facilities Cholla Common Facilities [Member] Cholla Power Plant [Member] Cholla Represent information pertaining to Cholla Power Plant. Cholla Units 2 and 3 [Member] Cholla Units 2 And 3 Represent information pertaining to Cholla Units 2 and 3. Climate Change Lawsuit Climate Change Lawsuit [Abstract] Climate Change Lawsuit [Member] Climate Change Lawsuit Represents information pertaining to the climate change lawsuit. Award Type [Axis] Coal Mine Reclamation Obligations [Member] Represents the obligations related to reimbursement to certain coal providers for amounts incurred for coal mine reclamation. Coal Mine Reclamation Obligations Coal Reclamation [Member] Reclamation liability that is associated with a legal obligation for the reclamation of coal properties. Coal reclamation Collateral Assurance Based on Rating Triggers Collateral assurance provided based on rating triggers Represents the collateral assurance provided that depends upon rating triggers such as a rating downgrade to non-investment grade under NEIL policies. Commitments and Contingencies [Line Items] Palo Verde Nuclear Generating Station Document Period End Date Common and Collective Trusts [Member] Investments made in common and collective trusts by the entity. Common and collective trusts: Component of Other Income and Other Expense Nonoperating [Table] Provides a description and amount of each detailed component of other nonoperating income and expenses. Offsetting Assets and Liabilities [Table] Disclosure of information about derivatives, financial assets and liabilities that are subject to offsetting, including enforceable master netting arrangements. SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF REGISTRANT Cost Recovery Mechanisms [Member] Cost Recovery Mechanisms Represents the cost recovery mechanisms. Costs Related to Investigation and Study under Superfund Site Costs related to investigation and study under Superfund site Costs related to site-wide groundwater remedial investigation and feasibility study work plan because subsidiary has been found to be potentially responsible parties ("PRPs") with liability for cleanup of hazardous substances that contaminates the soil, water or air, under the Comprehensive Environmental Response, Compensation and Liability Act ("Superfund"). Debt Instrument, Covenant Consolidated Debt to Total Consolidated Capitalization Ratio Ratio of consolidated debt to consolidated capitalization (as a percent) The consolidated debt to total consolidated capitalization ratio, which the entity is required to maintain pursuant to a debt covenant. Debt Instrument, Covenant Consolidated Debt to Total Consolidated Capitalization Ratio Actual Actual ratio of consolidated debt to total consolidated capitalization required to be maintained as per the debt covenant (as a percent) The actual consolidated debt to total consolidated capitalization ratio, which the entity is required to maintain pursuant to a debt covenant. Debt Instrument Daily Interest Rate Daily rate (as a percent) Represents the daily interest rate of the debt instrument. Entity [Domain] Debt Provisions Debt Provisions [Abstract] Deferred compensation Deferred Compensation [Member] Represents the regulatory asset under deferred compensation arrangements. Deferred contract termination charges to be amortized over a future period related to proposed acquisition of Southern California Edison Represents the deferred contract termination charges which will be amortized over a future period. Deferred Contract Termination Charges Deferred Credits and Other Deferred Credits [Member] Line item in the statement of financial position in which the fair value amounts of the derivative instruments are included. Deferred fuel and purchased power Deferred Fuel and Purchased Power Costs [Member] Fuel and purchased power costs incurred that would otherwise be charged to expense. These costs are included in allowable costs for rate making purposes and future revenue will be provided to permit recovery of such incurred costs. Deferred Fuel and Purchased Power Costs Deferred Fuel and Purchased Power MTM Costs [Member] Deferred fuel and purchased power - mark-to-market Fuel and purchased power MTM costs incurred that would otherwise be charged to expense. These costs are included in allowable costs for rate making purposes and future revenue will be provided to permit recovery of such incurred costs. Deferred fuel and purchased power regulatory asset (Note 3) Deferred Fuel and Purchased Power Regulatory Asset, Current Carrying amount as of the balance sheet date of deferred fuel and purchased power of regulated entities. Beginning balance Ending balance Carrying amount as of the balance sheet date of deferred fuel and purchased power of regulated entities that are expected to be reimbursed or refunded within one year or the normal operating cycle if longer. Deferred Fuel and Purchased Power Regulatory Asset (Liability), Current Change in regulatory asset Deferred Fuel and Purchased Power Regulatory Asset (Liability) [Roll Forward] Deferred fuel and purchased power regulatory liability Carrying amount as of the balance sheet date of deferred fuel and purchased power of regulated entities that are not expected to be reimbursed through revenue sources within one year or the normal operating cycle, if longer. Deferred fuel and purchased power regulatory liability (Note 3) Deferred Fuel and Purchased Power Regulatory Liability The component of income tax expense for the period representing the increase (decrease) in the entity's deferred tax assets and liabilities pertaining to continuing and discontinued operations. Deferred Income Tax Expense (Benefit) Continuing and Discontinued Operations Total deferred The component of income tax expense for the period representing the increase (decrease) in the entity's deferred tax assets and liabilities pertaining to discontinued operations. Deferred Income Tax Expense (Benefit) Discontinued Operations Discontinued operations Represents the costs incurred for income taxes that would otherwise be charged to expense. These costs represent probable future revenues and are expected to be recovered from customers through the ratemaking process. Deferred income taxes Deferred Income Taxes [Member] Pension and other postretirement benefits deferral Deferred Pension and Other Post Retirement Benefits [Member] Represents the regulatory asset under deferred pension and other post-retirement benefits. Deferred Tax Assets, Credit and Loss Carryforwards Credit and loss carryforwards The tax effect as of the balance sheet date of the amount of the future tax deductions attributable to credit and loss carryforwards. Deferred Tax Assets Real Estate Investments and Assets Held For Sale Real estate investments and assets held for sale The tax effect as of the balance sheet date of the amount of the estimated future tax reductions attributable to the difference between the tax basis and the generally accepted accounting principles basis of a company's real estate investments and assets held for sale which will decrease future taxable income when such basis difference reverses. Regulatory liabilities: Deferred Tax Assets, Regulatory Liabilities [Abstract] Deferred Tax Assets, Regulatory Liabilities, Asset Retirement Obligation and Removal Costs Asset retirement obligation and removal costs The tax effect as of the balance sheet date of the amount of the estimated future tax deductions attributable to regulatory liabilities related to asset retirement obligation and removal costs which can only be realized if sufficient taxable income is generated in future periods to enable the deduction to be taken. Deferred fuel and purchased power The tax effect as of the balance sheet date of the amount of the estimated future tax deductions attributable to regulatory liabilities related to deferred fuel and purchased power which can only be realized if sufficient taxable income is generated in future periods to enable the deduction to be taken. Deferred Tax Assets, Regulatory Liabilities, Deferred Fuel and Purchased Power Other The tax effect as of the balance sheet date of the amount of the estimated future tax deductions attributable to other regulatory liabilities which can only be realized if sufficient taxable income is generated in future periods to enable the deduction to be taken. Deferred Tax Assets, Regulatory Liabilities, Other Deferred Tax Assets, Regulatory Liabilities, Renewable Energy Standard Renewable energy standard The tax effect as of the balance sheet date of the amount of the estimated future tax deductions attributable to regulatory liabilities related to renewable energy standard which can only be realized if sufficient taxable income is generated in future periods to enable the deduction to be taken. Unamortized investment tax credits The tax effect as of the balance sheet date of the amount of the estimated future tax deductions attributable to regulatory liabilities related to unamortized investment tax credits, which can only be realized, if sufficient taxable income is generated in future periods to enable the deduction to be taken. Deferred Tax Assets Regulatory Liabilities Unamortized Investment Tax Credits The tax effect as of the balance sheet date of the amount of the estimated future tax reductions attributable to renewable energy incentives which can only be realized if sufficient taxable income is generated in future periods to enable the deduction to be taken. Deferred Tax Assets, Renewable Energy Incentives Renewable energy incentives Deferred Tax Liabilities, Regulatory Assets [Abstract] Regulatory assets: The amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the tax basis and the basis in accordance with generally accepted accounting principles of regulatory assets related to allowance for equity funds used during construction which will increase future taxable income when such basis difference reverses. Deferred Tax Liabilities, Regulatory Assets Allowance for Equity Funds Used During Construction Allowance for equity funds used during construction Deferred fuel and purchased power The amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the tax basis and the basis in accordance with generally accepted accounting principles of regulatory assets related to deferred fuel and purchased power which will increase future taxable income when such basis difference reverses. Deferred Tax Liabilities Regulatory Assets Deferred Fuel and Purchased Power The amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the tax basis and the basis in accordance with generally accepted accounting principles of regulatory assets related to deferred fuel and purchased power mark-to-market which will increase future taxable income when such basis difference reverses. Deferred Tax Liabilities, Regulatory Assets Deferred Fuel and Purchased Power Mark to Market Deferred fuel and purchased power - mark-to-market Deferred Tax Liabilities, Regulatory Assets, Other Other The amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the tax basis and the basis in accordance with generally accepted accounting principles of other regulatory assets which will increase future taxable income when such basis difference reverses. Deferred Tax Liabilities, Regulatory Assets, Pension and Other Postretirement Benefits Pension and other postretirement benefits The amount as of the balance sheet date of the estimated future tax effects attributable to the difference between the tax basis and the basis in accordance with generally accepted accounting principles of regulatory assets related to pension and other postretirement benefits which will increase future taxable income when such basis difference reverses. Amount related to the pretax cost of benefit changes, a portion of which has been recorded as a regulatory asset, which has not yet been recognized as components of net periodic benefit cost. Defined Benefit Plan, Accumulated Other Comprehensive Income, Regulatory Asset APS's portion recorded as a regulatory asset Defined Benefit Plan, Change in Fair Values of Plan Asset [Roll Forward] Changes in fair value for assets that are measured at fair value on a recurring basis A roll forward reconciliation of a concept from the beginning of a period to the end of a period. Amount of pension and other postretirement benefit costs deferred Represents the amount of pension and other postretirement benefit costs which were deferred. Defined Benefit Plan, Cost Deferred Effect of 1% decrease on other postretirement benefits expense, after consideration of amounts capitalized or billed to electric plant participants The effect of a one-percentage-point decrease in the assumed health care cost trend rates on the other postretirement benefits expense, after consideration of amount capitalized or billed to electric plant participants. Defined Benefit Plan Effect of One Percentage Point Decrease on Other Postretirement Benefits Expense Effect of 1% increase on other postretirement benefits expense, after consideration of amounts capitalized or billed to electric plant participants Defined Benefit Plan, Effect of One Percentage Point Increase on Other Postretirement Benefits Expense The effect of a one-percentage-point increase in the assumed health care cost trend rates on the other postretirement benefits expense, after consideration of amount capitalized or billed to electric plant participants. Defined Benefit Plan, Estimated Future Employer Contributions Percentage Approximate percentage of the subsidiary's contribution to the benefit plans relative to the consolidated entity's total contribution. APS's share of contributions to the plans (as a percent) Defined Benefit Plan, Fair Value of Plan Assets [Abstract] Fair value of Pinnacle West's pension plan and other postretirement benefit plan assets, by asset category APS's employees share of total cost of the plans (as a percent) Percentage of the subsidiary's share of the total cost of the benefit plans relative to the consolidated entity's total cost. Defined Contribution Plan, Cost Recognized Percentage 2010 DSMAC Represents the Demand-Side Management program which permits a surcharge for 2010 as part of customer bills to recover approved amounts for use on energy efficiency projects. Demand Side Management Adjustor Charge 2010 [Member] Represents the DSMAC program which permits a surcharge for 2012 as part of customer bills to recover approved amounts for use in energy efficiency projects. 2012 DSMAC Demand Side Management Adjustor Charge 2012 [Member] Represents the DSMAC program which permits a surcharge for 2013 as part of customer bills to recover approved amounts for use in energy efficiency projects. Demand Side Management Adjustor Charge 2013 [Member] 2013 DSMAC Derivative Collateral that Qualify for Scope Exception Obligation to Return Cash Collateral Provided from Counterparties, relating to non-derivative instruments or derivative instruments that qualify for a scope exception The amount of the obligation to return cash collateral relating to non-derivative instruments or derivative instruments that qualifies for a scope exception. Derivative Collateral that Qualify for Scope Exception Right to Reclaim Cash Collateral Provided to Counterparties, relating to non-derivative instruments or derivative instruments that qualify for a scope exception The amount of the right to reclaim cash collateral relating to non-derivative instruments or derivative instruments that qualify for a scope exception. Derivative Instrument Concentration of Risk Counterparties Concentration of credit risk, number of counterparties The number of counterparties involved in risk management contracts for which the concentration of risk is disclosed. The net gain (loss) reclassified from accumulated other comprehensive income into income on discontinuation of derivative instruments designated and qualifying as hedging instruments. Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income on Discontinuation Amount reclassified from accumulated other comprehensive income to earnings related to discontinued cash flow hedges Entity Well-known Seasoned Issuer Developed equities Represents information pertaining to developed equities. Developed Equities [Member] Entity Voluntary Filers Discontinued Operation Gain (Loss) on Disposal of Discontinued Operation Energy Related Products and Services Business, Net of, Tax Gain on sale of energy-related business Gain (loss) after tax expense or benefit, not previously recognized and resulting from the sale of a business component, which is recognized at the date of sale. A gain (loss) reflects the amount by which the consideration received exceeds (is exceeded by) the net carrying amount (reflecting previous provisions for loss on disposal, if any) of the energy related products and services disposal group. Gain on sale of energy-related products and services business Entity Current Reporting Status Tax (expense) benefit recognized by the parent company in accordance with an intercompany tax sharing agreement. Discontinued Operation Tax Effect of Discontinued Operation under Intercompany Tax Sharing Agreement Tax benefit in accordance with an intercompany tax sharing agreement Entity Filer Category Plant used in connection with distribution of energy. Distribution [Member] Distribution Entity Public Float Document and Entity Information Entity Registrant Name Electricity forward contracts Electricity Contracts [Member] Electricity contracts Represents derivative instruments with primary underlying risk tied to electricity contracts. Entity Central Index Key Emerging Equities [Member] Emerging equities Represents information pertaining to emerging equities. Represents information pertaining to alternative investments. Equity and Long Term Debt Less Current Maturities and Leaseback The sum of total shareholder equity and long-term debt, excluding current maturities of long-term debt and leaseback. Total capitalization Equity in Earnings (Losses) of Subsidiaries Equity in earnings of subsidiaries Equity in earnings of subsidiaries - net Represents the equity in earnings or losses of subsidiaries for the reporting period. Equity Securities International Companies [Member] This category includes information about ownership interests or the right to acquire ownership interests in international companies which ownership interest is represented by shares of common or preferred stock (which is neither mandatorily redeemable no redeemable at the option of the holder), convertible securities, stock rights, or stock warrants. International Companies, Equities Entity Common Stock, Shares Outstanding Equity Securities US Companies [Member] This category includes information about ownership interests or the right to acquire ownership interests in U.S. companies which ownership interest is represented by shares of common or preferred stock (which is neither mandatorily redeemable no redeemable at the option of the holder), convertible securities, stock rights, or stock warrants. U.S. Companies, Equities Estimated Share of Costs Related to on Site Interim Storage of Spent Nuclear Fuel Estimated share of the costs related to on-site interim storage of spent nuclear fuel Represents the estimated share of costs related to the on-site interim storage of spent nuclear fuel, which is to be incurred over the current life of Palo Verde with respect to the Palo Verde Nuclear Generating Station. Sublimit for non-nuclear property damage losses which has been imposed to the primary policy offered Represents the amount of sublimit for non-nuclear property damage losses which has been imposed to the primary policy offered during the reporting period. Primary Policy Offered Sublimit for Non Nuclear Property Damage Losses Accidental Outage Policy Sublimit for Non Nuclear Losses Sublimit for non-nuclear losses which has been imposed to the accidental outage policy Represents the amount of sublimit for non-nuclear losses which has been imposed to the accidental outage policy during the reporting period. Represents the expiration of amortization period of costs and prior year credits. Expiration of Amortization Period of Costs and Prior Year Credits Expiration of amortization period of costs and prior year credits Changes in fair value for our risk management activities assets and liabilities that are measured at fair value on a recurring basis using Level 3 inputs Fair Value, Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation Calculation [Roll Forward] Electricity forward price (per MWh) Represents the electricity forward price per Megawatt Hours, used as an input to measure fair value. Fair Value Inputs, Electricity Forward Price Per Megawatt Hours Fair Value Inputs, Gas Forward Price Per Metric Million British Thermal Units Natural gas forward price (per MMbtu) Represents the gas price per Metric Million British Thermal Units, used as an input to measure fair value. Fair Value Inputs, Implied Electricity Volatilities Electricity price volatilities (as a percent) Represents the percentage of implied electricity volatilities. Natural gas price volatilities (as a percent) Represents the percentage of implied electricity natural gas price volatilities. Fair Value Inputs, Implied Gas Price Volatilities Represents a price per Megawatt Hours, used as an input to measure fair value. Fair Value Inputs Prices Per Megawatt Hours Prices (per MWh) Fair Value Inputs, Prices Per Metric Million British Thermal Units Prices (per mmbtu) Represents a price per Metric Million British Thermal Units , used as an input to measure fair value. This item represents the amount of the total change in unrealized (holding) gains or losses for the period which are included in the statement of income (or changes in net assets) in other income. Such unrealized (holding) gains or losses relate to those assets and liabilities that are still held at the reporting date for which fair value is measured on a recurring basis using significant unobservable inputs (Level 3). Fair Value, Liabilities Measured on Recurring Basis Asset and Liability, Change in Unrealized Gain (Loss), Included in Other Income Net unrealized gains included in earnings related to instruments still held at end of period Total net gains (losses) realized/unrealized: Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liability, Gain (Loss) [Abstract] Settlements that had taken place during the period in relation to assets and liabilities measured at fair value and categorized within Level 3 of the fair value hierarchy. Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liability, Settlements Settlements Transfers into Level 3 from Level 2 Transfers into assets and liabilities measured at fair value and categorized within Level 3 of the fair value hierarchy that had taken place during the period. Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis Asset and Liability, Transfers into Level 3 Transfers from Level 3 into Level 2 Transfers out of assets and liabilities measured at fair value and categorized within Level 3 of the fair value hierarchy that had taken place during the period. Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis Asset and Liability, Transfers Out of Level 3 Document Fiscal Year Focus Net derivative balance at beginning of period This element represents assets and liabilities measured at fair value using significant unobservable inputs (Level 3) which are required for reconciliation purposes of beginning and ending balances. Net derivative balance at end of period Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis Asset and Liability, Value Document Fiscal Period Focus Deferred as a regulatory asset or liability This element represents the total gains or losses for the period (realized and unrealized), arising from assets and liabilities measured at fair value on a recurring basis using unobservable inputs (Level 3), which have been deferred as a regulatory asset or liability. Fair Value Measurement with Unobservable Inputs Reconciliation Recurring Basis, Derivative Gain (Loss) Deferred as Regulatory Asset or Liability Amount of federal and state loss carryforwards which begin to expire in 2013 Represents the amount of other federal and state loss carryforwards which expires in 2013. Federal and State Loss Carryforwards which Begin to Expire in 2013 Federal and State Loss Carryforwards which Begin to Expire in 2014 Represents the amount of other federal and state loss carryforwards which expires in 2014. Amount of federal and state loss carryforwards which begin to expire in 2014 Amount of federal and state loss carryforwards which begin to expire in 2017 Federal and State Loss Carryforwards which Begin to Expire in 2017 Represents the amount of other federal and state loss carryforwards which expires in 2017. Federal General Business Credits Carryforwards Expiration Amount Amount of federal general business credits carryforwards which begin to expire in 2031 Represents the amount of federal general business credits carryforwards which expires in 2031. Represents the amount of federal general business credits carryforwards which expires in 2029. Amount of federal general business credits carryforwards which begin to expire in 2029 Federal General Business Credits Carryforwards Expiration in 2029 Amount Represents the amount of federal general business credits carryforwards which expires in 2031. Federal General Business Credits Carry forwards Expiration in 2031 Amount Amount of federal general business credits carryforwards which begin to expire in 2031 Federal General Business Credits Carryforwards whose Realization would be Delayed on Recognition of Cash Benefit Represents federal general business credit carryforwards whose realization will be delayed on recognition of cash benefit. Federal general business income tax credit carryforwards whose realization will be delayed on recognition of cash benefit Federal General Business Credits Carryforwards Whose Realization Would be Delayed on Recognition of Cash Benefit Current Federal general business income tax credit carryforwards Represents the current portion of federal general business credit carryforwards which will be realized within the next twelve months. Amount of federal net operating losses carryforwards which begin to expire in 2031 Federal Net Operating Losses Carryforwards Expiration Amount Represents the amount of federal net operating losses carryforwards which expires in 2031. Represents the amount of federal net operating losses carryforwards which expires in 2029. Amount of federal net operating losses carryforwards which begin to expire in 2029 Federal Net Operating Losses Carryforwards Expiration in 2029 Amount Legal Entity [Axis] Federal Net Operating Losses Carry forwards Expiration in 2031 Amount Amount of federal net operating losses carryforwards which begin to expire in 2031 Represents the amount of federal net operating losses carryforwards which expires in 2031. Document Type Filing with Arizona Corporation Commission [Member] Represents the filing with the Arizona Corporation Commission. Filing with the Arizona Corporation Commission Financial Assurances [Abstract] Financial Assurances Forward Component of PSA Rate Forward component of increase in PSA (in dollars per kWh) Represents the forward component of increase in PSA. Four Corners common [Member] Represents Four Corners common, a jointly-owned generating facility of the entity. Four Corners Common Four Corners [Member] Four Corners Represent information pertaining to Four Corners. Four Corners Switchyards [Member] Represents Four Corners Switchyards, a jointly-owned transmission facility of the entity. Four Corners Switchyards Four Corners Units 4 and 5 [Member] Represents Four Corners Units 4 and 5, a jointly-owned generating facility of the entity. Four Corners Units 4 and 5 Four Corners Units 4, 5 and Common Gain on sale of energy-related products and services business Represents gain (loss) on sale of energy-related products and services business. Gain on Sale of Energy Related Products and Services Business 2008 General retail rate case Rate case application filed in 2008, which was settled in 2009. General Retail Rate Case 2008 [Member] Retail rate case filing Represents the general retail rate case filing. Retail Rate Case Filing [Member] Grant 2007 [Member] Represents the grant of equity based awards made in 2007. 2007 grant Summary of Significant Accounting Policies 2008 grant Grant 2008 [Member] Represents the grant of equity based awards made in 2008. Represents the grant of equity based awards made in 2009. 2009 grant Grant 2009 [Member] Grant 2010 [Member] Represents the grant of equity based awards made in 2010. 2010 grant Grant 2011 [Member] Represents the grant of equity based awards made in 2011. 2011 grant Grant 2012 [Member] Represents the grant of equity based awards made in 2012. 2012 grant Guarantee Obligations Terms Guarantees, Term Represents the approximate term of the guarantee or each group of similar guarantees. Historical Component of PSA Rate Historical component of increase in PSA (in dollars per kWh) Represents the historical component of increase in PSA. Incentive Shares [Member] Incentive Shares as awarded by the company to their employees as a form of incentive compensation. Incentive Shares Total income tax expense The sum of the current income tax expense or benefit and the deferred income tax expense or benefit pertaining to continuing and discontinued operations. Income Tax Expense (Benefit) Continuing and Discontinued Operations Income taxes Income Tax [Line Items] Allowance for equity funds used during construction The portion of the difference between total income tax expense or benefit as reported in the income statement for the period and the expected income tax expense or benefit computed by applying the domestic federal statutory income tax rates to pretax income from continuing operations attributable to allowance for equity funds used during construction. Income Tax Reconciliation Allowance for Equity Funds Used During Construction Increases (reductions) in tax expense resulting from: Income Tax Reconciliation Increases Reductions in Tax Expense [Abstract] Credits and favorable adjustments related to prior years resolved in current year Income Tax Reconciliation Tax Credits and Adjustments Prior Years Represents the credits and favorable adjustments related to prior years resolved in current year. Income Taxes [Abstract] Income Taxes Income Taxes, additional disclosures Income Taxes Additional Disclosures [Abstract] Deferred fuel and purchased power amortization The amortization of deferred fuel and purchased power costs. Amounts charged to customers Increase (Decrease) Deferred Fuel and Purchased Power Amortization Increase (Decrease) in Income from Continuing Operations Decrease in income from continuing operations The increase (decrease) during the reporting period in income from continuing operations. Reduction in operating income The increase (decrease) during the reporting period in operating income. Increase (Decrease) in Operating Income Increase (Decrease) in Operating Revenues Reduction in operating revenues The increase (decrease) during the reporting period in operating revenues. Increase (Decrease) in Operations and Maintenance Reduction in operations and maintenance The increase (decrease) during the reporting period in operations and maintenance expense. Investments made in common and collective trusts that primarily invest in international equities. International Equities International Equity Securities [Member] Investment in Subsidiaries Investments in subsidiaries Represents investments in subsidiaries. INVESTMENTS AND OTHER ASSETS Investments and Other Assets [Abstract] Investments and other assets Represents the disclosure for jointly-owned facilities. Jointly Owned Utility Plants [Text Block] Jointly-Owned Facilities Line of Credit Facility, Commercial Paper Program Maximum Borrowing Capacity Maximum commercial paper support available under credit facility Represents the maximum borrowings available for the commercial paper program under the terms of line of credit facility. Number of line of credit facilities Line of Credit Facility, Number of Agreements Represents the number of line of credit facilities. Represents the number of credit facilities. Line of Credit Facility Number of Facilities Number of credit facilities Revolving credit facility maturing in 2010 Represents the revolving credit facility maturing in 2010. Line of Credit Maturing in 2010 [Member] Represents the information pertaining to the Line of Credit maturing in 2011. Line of Credit Maturing in 2011 [Member] Line of Credit Maturing in 2011 Revolving credit facility maturing in 2015 Represents the revolving credit facility maturing in 2015. Line of Credit Maturing in 2015 [Member] Line of Credit Maturing in 2018 [Member] Revolving credit facility maturing in 2018 Represents the revolving credit facility maturing in 2018. Line of Credit Maturing in 2016 [Member] Revolving credit facility maturing in 2016 Represents the credit facility maturing in 2016. Lines of Credit and Short-Term Borrowings Thereafter Amount of long-term debt maturing after the fourth full fiscal year following the date of the most recent balance sheet presented in the financial statements. Long Term Debt, Maturities, Repayments of Principal after Fourth Full Fiscal Year Loss Contingencies and Environmental Liabilities [Policy Text Block] Loss Contingencies and Environmental Liabilities Disclosure of accounting policy for loss contingencies and environmental liabilities. Lost Fixed Cost Recovery Mechanisms [Member] Lost Fixed Cost Recovery Mechanism Represents lost fixed cost recovery mechanism. The amount of cash or securities placed with a broker or counterparty as security for a trading or derivatives securities position which was partially obtained with funds provided by the broker dealer and the right to reclaim cash collateral under master netting arrangements that have not been offset against net derivative instrument positions. Margin Deposit Assets and Derivative Collateral Right to Reclaim Cash Margin and Collateral Provided to Counterparties Represents the maximum amount APS could incur under the current NEIL (Nuclear Electric Insurance Limited) policies for each retrospective assessment declared by NEIL's Board of Directors due to losses. Maximum Amount that Could be Incurred under Retrospective Assessment of NEIL Policies Maximum amount that APS could incur under the current NEIL policies for each retrospective assessment Represents the maximum assessment per reactor under the program for each nuclear incident. Maximum Assessment Per Reactor for Each Nuclear Incident Maximum retrospective premium assessment per reactor for each nuclear liability incident Maximum available nuclear liability insurance Represents the maximum available nuclear liability insurance which is provided by commercial insurance carriers, maintained by Palo Verde as required by the Price Anderson Nuclear Industries Indemnity Act. Maximum Available Nuclear Liability Insurance Amount of cash tax benefits that may be available Represents the amount of cash tax benefits that may be available if provision is made as per American Taxpayer Relief Act of 2012. Maximum Cash Tax Benefits that May be Available Accounts receivable Accounts Receivable, Gross, Current Customer and other receivables Maximum Insurance Coverage Per Incident Maximum insurance against public liability per occurrence for a nuclear incident Represents the maximum insurance amount against public liability per occurrence for a nuclear incident. Represents the maximum potential retrospective assessment per incident based on the interest of APS in the three Palo Verde units. Maximum Potential Retrospective Assessment Per Incident Maximum potential retrospective assessment per incident of APS Amount of miscellaneous other nonoperating expenses resulting from ancillary business-related activities (that is, excluding major activities considered as a part of the normal operations of the business). Miscellaneous Other Nonoperating Expense Miscellaneous Miscellaneous Other Nonoperating Income Miscellaneous Amount of miscellaneous other nonoperating income resulting from ancillary business-related activities (that is, excluding major activities considered as a part of the normal operations of the business). Morgan-Pinnacle Peak System Morgan Pinnacle Peak System [Member] Represents Morgan-Pinnacle Peak System, a jointly-owned transmission facility of the entity. Natural gas forward contracts Natural Gas Contracts [Member] Natural gas contracts Represents derivative instruments with primary underlying risk tied to natural gas contracts. Navajo Generating Station Units 1, 2 and 3 Navajo Generating Station Units 1, 2 and 3 [Member] Represents Navajo Generating Station Units 1, 2 and 3, a jointly-owned generating facility of the entity. Represent information pertaining to Navajo Generating Station. Navajo Generating Station [Member] Navajo Plant Represents Navajo Southern System, a jointly-owned transmission facility of the entity. Navajo Southern System Navajo Southern System [Member] Netting, Collateral and Other [Member] This item represents the amount of cash collateral held or placed with counterparties, the impact of netting across the levels of the fair value hierarchy, and net payables or net receivables related to pending securities sales and purchases. Other The aggregate fair value of additional assets that would be required to be posted as collateral for non-derivative instruments with credit-risk related contingent features if the credit-risk-related contingent features were triggered at the end of the reporting period. Non Derivative Credit Risk Contract Additional Collateral Aggregate Fair Value Additional collateral to counterparties for energy related non-derivative instrument contracts Nonmonetary Notional Amount of Price Risk Cash Flow Hedge Derivatives 1 Aggregate notional amounts of price risk derivatives designated as a cash flow hedge with notional amounts expressed in a nonmonetary unit. For example the number of barrels specified in a fuel oil forward purchase contract. Outstanding gross notional amount of derivative instruments Nonmonetary Notional Amount of Price Risk Cash Flow Hedge Derivatives 2 Aggregate notional amount of price risk derivatives designated as a cash flow hedge with a notional amounts expressed in nonmonetary units. For example the number of barrels specified in a fuel oil forward purchase contract. Outstanding gross notional amount of derivative instruments Amount of nonoperating costs resulting from the ancillary business-related activities (that is, excluding major activities considered as a part of the normal operations of the business) recognized during the period. Non-operating costs Nonoperating Costs Income taxes Nonoperating Income Tax Expense (Benefit) The sum of the current income tax expense (benefit) and the deferred income tax expense (benefit) pertaining to non-operating income. North Valley System North Valley System [Member] Represents North Valley System, a jointly-owned transmission facility of the entity. Nuclear Fuel Nuclear Fuel [Abstract] Accounts payable Accounts Payable, Current Number of Non Financial Separate Performance Metrics Based on which Awards, Vest Number of non-financial separate performance metrics based on which awards vest Represents the number of non-financial separate performance metrics based on which the awards vest. Number of Shares of Stock Awarded for Each Unit Award Earned The number of shares awarded to an employee for each unit award earned. The cash payment is calculated by multiplying the shares awarded by the fair market value of a share determined at a pre-established valuation date. The number of shares used to determine the cash award payable to an employee for each unit earned Number of VIE Lessor Trusts Number of VIE lessor trusts with whom agreements have been made to sell and lease back interests in certain nuclear generating assets and related common facilities. Number of VIE lessor trusts Oil Companies Number Number of oil companies Represents the number of oil companies against which lawsuits were filed. Transmission Rates, Transmission Cost Adjustor and Other Transmission Matters Represents the formula rate-setting methodology to reflect and recover costs incurred in providing transmission services. Open Access Transmission Tariff [Member] Operating margin The net result for the period of deducting operating expenses, excluding depreciation and amortization, from operating revenues. Operating Income (Loss) Excluding Depreciation and Amortization Operating Income Tax Expense (Benefit) The sum of the current income tax expense (benefit) and the deferred income tax expense (benefit) pertaining to operating income. Income taxes Operating Licenses Extension, Period Extension period of operating licenses for each of the three Palo Verde units Represents the extension period of operating licenses. License extension approved by the NRC Option Model Valuation Technique [Member] Option model valuation technique used to measure fair value. Option model The total amount of other operating cost and expense items that is associated with the entity's normal revenue producing operation excluding depreciation and amortization. Other Cost and Expense Operating Excluding Depreciation and Amortization Other operating expenses Plant used in connection with other generation of energy. Other generation [Member] Other generation Other Regulatory Liabilities [Member] Miscellaneous regulatory liabilities which are individually insignificant. Other Ownership Percentage for Classification as Cost Method Investments Ownership percentage for classification as cost method investments by El Dorado Represents the maximum ownership percentage for the classification of investments as cost method investments. Represents the PSA rate (power supply adjustor) which provides for the adjustment of retail rates to reflect variations in retail fuel and purchased power costs. PSA Rate PSA rate (in dollars per kWh) Represents the PSA rate prior for the prior years (power supply adjustor) which provides for the adjustment of retail rates to reflect variations in retail fuel and purchased power costs. PSA Rate in Prior Years PSA rate for prior year (in dollars per kWh) PSA Rate Maximum Increase (Decrease) Increase or decrease in PSA charge (in dollars per kWh) Represents the increase or decrease in PSA rate (power supply adjustor) which provides for the adjustment of retail rates to reflect variations in retail fuel and purchased power costs. Palo Verde Common [Member] Palo Verde Common Represents Palo Verde Common, a jointly-owned generating facility of the entity. Palo Verde - Estrella 500kV System Palo Verde Estrella 500kV System [Member] Represents Palo Verde - Estrella 500KV System, a jointly-owned transmission facility of the entity. Palo Verde Lessor Trusts [Member] Palo Verde Lessor Trusts Represents Palo Verde Lessor Trusts, a consolidated variable interest entity. Palo Verde Sale Leaseback [Member] Represents Palo Verde Sale Leaseback, a jointly-owned generating facility of the entity. Palo Verde Sale Leaseback Palo Verde Unit 2 [Member] Represents Palo Verde Unit 2, a jointly-owned generating facility of the entity. Palo Verde Unit 2 Palo Verde Units 1 and 3 [Member] Represents Palo Verde Units 1 and 3, a jointly-owned generating facility of the entity. Palo Verde Units 1 and 3 Palo Verde Yuma 500kV System [Member] Represents Palo Verde - Yuma 500KV System, a jointly-owned transmission facility of the entity. Palo Verde - Yuma 500kV System Payments to Consolidated Subsidiaries Investments in subsidiaries Represents the cash outflow associated with the contributions paid to the consolidated subsidiaries of the entity. Pension and other postretirement benefits Carrying value of pension and other postretirement benefit costs under current regulatory conditions. These costs are a form of a regulatory asset that are expected to be recoverable through rate adjustments. Pension and Other Post Retirement Benefits [Member] Percentage of the awards that vest based on non-financial separate performance metrics Represents the percentage of the awards that vest based on non-financial separate performance metrics. Percentage of Awards, that Vest Based on Non Financial Separate Performance Metrics Represents the percentage of the equity based awards that vest based on a percentile ranking of the Company's earnings per share growth rate compared with the earnings per share growth rate of all relevant companies in a specified utilities index. Percentage of Awards, that Vest Based on Percentile Ranking of Earnings Per Share, Growth Rate Percentage of the awards that vest based on a percentile ranking of earnings per share growth rate Percentage of the awards that vest based on a percentile ranking of total shareholder return Represents the percentage of the equity based awards that vest based on a percentile ranking of total shareholder return compared with the total shareholder return of all relevant companies in a specified utilities index. Percentage of Awards, that Vest Based on Percentile Ranking of Total Shareholder Return Percentage of Bonus Depreciation for Income Tax Regarding Qualified Property Placed into Service Percentage of bonus depreciation for federal income tax purposes Represents the percentage of bonus depreciation for federal income tax purposes in relation to qualified property placed into service as per American Taxpayer Relief Act of 2012. Percentage of Cash in which Election to Receive Dividend Equivalent Payment May be Made by Participants for Deferrals Option One Percentage of cash that the participant may elect as a dividend equivalent deferral under the first option available under the plan Represents the percentage of cash that the participant may elect as a deferred dividend equivalent payment under the first option available under the plan. Percentage of Cash in which Election to Receive Payment May be Made by Participants for Deferrals Option One Represents the percentage of cash that the participant may elect as a deferred grant under the first option available under the plan. Percentage of cash that the participant may elect as a deferral under the first option available under the plan Percentage of Fully Transferable Shares of Stock in which Election to Receive Dividend Equivalent Payment May be Made by Participants for Deferrals Option One Percentage of fully transferable shares of stock that the participant may elect as a dividend equivalent deferral for the first option available under the plan Represents the percentage of fully transferable shares of stock that the participant may elect as a deferred dividend equivalent payment for the first option available under the plan. Percentage of Fully Transferable Shares of Stock in which Election to Receive Dividend Equivalent Payment May be Made by Participants for Deferrals Option Two Percentage of fully transferable shares of stock that the participant may elect as a dividend equivalent deferral for the second option available under the plan Represents the percentage of fully transferable shares of stock that the participant may elect as a deferred dividend equivalent payment for the second option available under the plan. Percentage of fully transferable shares of stock that the participant may elect as a deferral for the first option available under the plan Represents the percentage of fully transferable shares of stock that the participant may elect as a deferred grant for the first option available under the plan. Percentage of Fully Transferable Shares of Stock in which Election to Receive Payment May be Made by Participants for Deferrals Option One Percentage of fully transferable shares of stock that the participant may elect as a deferral for the second option available under the plan Represents the percentage of fully transferable shares of stock that the participant may elect as a deferred grant for the second option available under the plan. Percentage of Fully Transferable Shares of Stock in which Election to Receive Payment May be Made by Participants for Deferrals Option Two Percentage of unrealized gains and losses on certain derivatives deferred for future rate treatment Percentage of unrealized gains and losses on certain derivatives deferred for future rate treatment pursuant to the PSA mechanism that would otherwise be recognized in income. Percentage of Unrealized Gains and Losses on Certain Derivatives Deferred for Future Rate Treatment Percentage of Unrealized Gains and Losses on Certain Derivatives Deferred for Future Rate Treatment before Accounting Treatment Change Percentage of unrealized gains and losses on certain derivatives deferred for future rate treatment pursuant to the PSA mechanism that would otherwise be recognized in income before accounting treatment change. Percentage of unrealized gains and losses on certain derivatives deferred for future rate treatment before accounting treatment change Performance Share Awards Performance Share Awards [Member] Share awards that vest based on performance of the employees. These share awards are allotted only if certain company wide performance criteria are met, such as earnings per share growth rate, total shareholder return, etc. Period of License Extension Approved by NRC Period of license extension approved by the NRC Represents the period of license extension approved by the NRC, which extends the commencement of decommissioning to 2045. Represents the period to provide collateral assurance based on rating triggers such as a rating downgrade to non-investment grade under NEIL policies (in days). Period to Provide Collateral Assurance Based on Rating Triggers Period to provide collateral assurance based on rating triggers Phoenix Mead System [Member] Represents Phoenix - Mead System, a jointly-owned transmission facility of the entity. Phoenix - Mead System Pollution Control Bonds Fixed [Member] A debt security issued by a state, certain agencies or authorities, a local government, or development corporation to finance the construction of air- or water-pollution control facilities or sewage or solid waste disposal facilities pursuant to federal law and which is carrying a fixed interest rate. Pollution Control Bonds - Fixed A debt security issued by a state, certain agencies or authorities, a local government, or development corporation to finance the construction of air- or water-pollution control facilities or sewage or solid waste disposal facilities pursuant to federal law. Total Pollution Control Bonds Pollution Control Bonds [Member] Pollution Control Bonds - Variable A debt security issued by a state, certain agencies or authorities, a local government, or development corporation to finance the construction of air- or water-pollution control facilities or sewage or solid waste disposal facilities pursuant to federal law and which is carrying a variable interest rate. Pollution Control Bonds Variable [Member] Pollution Control Bonds with Senior Notes [Member] A debt security issued by a state, certain agencies or authorities, a local government, or development corporation to finance the construction of air- or water-pollution control facilities or sewage or solid waste disposal facilities pursuant to federal law. The bonds are backed by the credit of the beneficiary of the financing and with senior notes rather than the credit of the issuer. Pollution control bonds with senior notes Pollution Control Revenue Refunding Bonds 2009 Series A [Member] Pollution Control Revenue Refunding Bonds, 2009 Series A A contractual arrangement to borrow and repay an amount under Pollution Control Revenue Refunding Bonds, 2009 series A. United States UNITED STATES A contractual arrangement to borrow and repay an amount under Pollution Control Revenue Refunding Bonds, 2002 series A. Pollution Control Revenue Refunding Bonds, 2002 Series A Pollution Control Revenue Refunding Bonds 2002 Series A [Member] A contractual arrangement to borrow and repay an amount under pollution control revenue refunding bonds, 2009 series B. Pollution Control Revenue Refunding Bonds 2009 Series B [Member] Pollution Control Revenue Refunding Bonds, 2009 Series B Power Companies Number Number of power companies Represents the number of power companies against which lawsuits were filed. Commodity - Power Represents power related derivative commodity of the entity. Power [Member] Power Outage [Abstract] Southwest Power Outage Power Outage Capacity of Firm Load Affected Capacity of firm load that were reported to have been affected due to outages affecting portions of southern Arizona, southern California and northern Mexico (in MW) Represents the capacity of firm load that were reported to have been affected due to outages affecting portions of specified regions. Represents the capacity of transmission line that tripped out of service related to the power outage. Power Outage Capacity of Transmission Line that Tripped out of Service Capacity of transmission line that tripped out of service (in kV) Pollution Control Revenue Refunding Bonds 2009 Series C [Member] Pollution Control Revenue Refunding Bonds, 2009 Series C A contractual arrangement to borrow and repay an amount under pollution control revenue refunding bonds, 2009 series C. Maximum possible fine per violation per day that the violation is found to have been in existence Represents the maximum possible fine per violation per day that the violation is found to have been in existence. Power Outage Inquiry Maximum Possible Fine Per Violation Per Day Number of customers losing service in Yuma area Represents the number of customers losing service after the generation and transmission resources were lost in the power outage. Power Outage Number of Customers Losing Service Number of customers that were reported to have been affected due to outages Represents the number of customers that were reported to have been affected due to outages affecting portions of specified regions. Power Outage Number of Customers Affected Represents the period, after the transmission line went off-line, until the generation and transmission resources were lost in the power outage. Power Outage Period Over which Generation and Transmission Resources were Lost Period, after the transmission line went off-line, over which generation and transmission resources for the Yuma area were lost Power Supply Adjustor (PSA) Represents the Power Supply Adjustment Plan which permits a surcharge for variations in retail fuel and purchased power costs. Power Supply Adjustor [Member] Other Prepaid Option, Premiums and Other Derivative instrument netting, options, and other risk management contracts. Proceeds from Dividends Received from Subsidiaries Dividends received from subsidiaries Represents dividends received from subsidiaries. Proceeds from sale of energy-related products and services business Proceeds from Sale of Energy Related Products and Services Business Represents the proceeds from the sale of energy-related products and services business during the reporting period. Charges for the permanent disposal of spent nuclear fuel (in dollars per kWh) Represents the rate charged for the permanent disposal of spent nuclear fuel. Public Utilities Disposal of Spent Nuclear Fuel Rate Public Utility Financing Application, Long Term Debt Authorization Long-term debt authorization requested in a financing application Represents the long-term debt authorization requested in a financing application filed with a regulatory authority. Public Utility Order Common Stockholders Equity Ratio Required common equity ratio ordered by ACC (as a percent) 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. Public Utility Order Dividend Restrictions Shareholder Equity Dividend restrictions, shareholder equity required The amount of total shareholder equity required in order for the entity to pay dividends pursuant to an order from a regulatory authority. Long-term debt authorization Represents the long-term debt authorization pursuant to an order from a regulatory authority. Public Utility Order Long Term Debt, Authorization Public Utility Order Long Term Debt, Authorization before Increase Long-term debt authorization before increase Represents the long-term debt authorization before the increase pursuant to an order from a regulatory authority. Percentage of APS's capitalization used in calculation of short-term debt authorization Represents the percentage of capitalization which is used to calculate the short-term debt authorization pursuant to an order from a regulatory authority. Public Utility Order Short Term Debt Authorization as Percentage of Capitalization Represents the short-term debt authorization as a percentage of capitalization pursuant to an order from a regulatory authority before the increase. Public Utility Order Short Term Debt Authorization as Percentage of Capitalization, before Increase Short-term debt authorization as a percentage of APS's capitalization before increase Public Utility Order Short Term Debt Authorization, Fixed Amount Required amount to be used in purchases of natural gas and power which is used in calculation of short-term debt authorization Represents the fixed amount required to be used for purchases of natural gas and power which is used to calculate the short-term debt authorization pursuant to an order from a regulatory authority. Rate Matter Additional Capacity from AZ Sun Projects Additional capacity from APS-owned AZ Sun projects (in MW) Represents the additional capacity from APS-owned AZ Sun projects. Total capacity from APS-owned AZ Sun projects (in MW) Represents the aggregate capacity from APS-owned AZ Sun projects. Rate Matter Aggregate Capacity from AZ Sun Projects Rate Matter, Amount by which Proposed Budget Exceeds Approved Budget Amount by which proposed budget exceeds approved budget Represents the amount by which proposed budget exceeds approved budget. Amount of approved budget Represents the amount of approved budget. Rate Matter, Approved Budget Represents the remaining capacity from APS-owned AZ Sun projects. Rate Matter Remaining Capacity from AZ Sun Projects Remaining capacity from APS-owned AZ Sun projects (in MW) Rate Matter, Approved Budget for Residential Distributed Energy Amount of approved budget for residential distributed energy up-front incentives Represents the amount of approved budget residential distributed energy. Represents the amount of approved commercial distributed energy up-front incentives. Rate Matter, Approved for Commercial Distributed Energy Amount of approved budget for commercial distributed energy up-front incentives Rate Matter, Approximate Percentage of Increase in Average Retail Customer Bill Approximate percentage of increase in the average retail customer bill Approximate percentage of increase in the average retail customer bill due to request for net retail base rate increase. Rate Matter Approximate Percentage of Increase in Average Retail Customer Bill for Specific Transaction Approximate percentage of increase in the average retail customer bill due to request for net retail base rate increase for the Four Corners transaction. Approximate percentage of increase in the average retail customer bill under proposed Four Corners rate filing Current base fuel rate (in dollars per kWh) Rate Matter, Base Fuel Rate Current Represents the current base rate for fuel and purchased power costs. Proposed base fuel rate (in dollars per kWh) Rate Matter Base Fuel Rate Proposed Represents the proposed base rate for fuel and purchased power costs. Base rate decrease Rate Matter Base Rate Decrease Amount of decrease in base rates in an application filed of a regulatory matter for fuel and purchased power costs currently addressed through a surcharge. Rate Matter, Amortization of Costs Recovered Through Surcharge Amortization of recovery of demand-side management adjustor charge included in costs already been recovered Represents the amount of amortization of the portion of costs for a specific program which is being recovered through a surcharge. Rate Matter, Cost Recovery Amortization Period Period over which program costs will be amortized Represents the period of time over which the costs incurred will be recovered. Represents the period covered by the cost recovery program due to a change in the recovery method from historical basis to concurrent basis. Period covered by cost recovery program Rate Matter, Cost Recovery Period Percentage of cumulative energy savings for current year Represents the percentage of cumulative energy savings for current year. Rate Matter, Cumulative Energy Savings for Current Year Percentage Represents the percentage of cumulative energy savings for prior year. Percentage of cumulative energy savings for prior year Rate Matter, Cumulative Energy Savings for Prior Year Percentage Rate Matter, Energy Savings Goal, Percentage Percentage of annual energy savings to meet energy efficiency goal for 2011 Represents the annual energy savings goal expressed as a percent of total energy resources needed to meet the retail load. Rate Matter, Energy Savings Goal Term Period of energy savings goal Represents term of annual energy savings to meet energy efficiency goal for 2011. Rate Matter, Findings Period ACC staff sufficiency findings, general period of time The period of time which the staff of the regulatory entity generally requires prior to issuance of its findings. Rate Matter, Fixed Cost Recoverable Per Non Residential Power Lost Fixed costs recoverable per non-residential power lost (in dollars per kWh) Represents fixed costs recovered by the LFCR mechanism per non-residential kWh lost. Fixed costs recoverable per residential power lost (in dollars per kWh) Represents fixed costs recovered by the LFCR mechanism per residential kWh lost. Rate Matter, Fixed Cost Recoverable Per Residential Power Lost Rate Matter, Funded Amount Costs already being recovered in general rates Represents the amount of costs for a specific program which is being recovered through the rate base. Rate Matter, Funding Approved Budget Authorized Funding approval as per budget authorized Represents the funding approval as per budget which has been authorized. Rate Matter, Funding Request The amount of funding requested for inclusion in the rate base for a specific project. Funding request Rate Matter, Investment Commitment for Development of New Solar Generation Investment commitment for development of new solar generation Represents the minimum amount of investment commitment for development of new solar generation. Rate Matter, Plan Term Plan term The period of time covered by a plan to implement a standard enacted by a regulatory authority. Period to process the subsequent rate cases The period of time subsequent to the findings of the staff of the regulatory entity in which the parties agreed to process the rate matter in good faith. Rate Matter, Process Period Amount of proposed budget Represents the amount of proposed budget. Rate Matter, Proposed Budget Rate Matter, Solar Capacity Generation Contracts Executed Capacity of new solar generation contracts executed (in MW) Represents the capacity of new solar generation contract executed. Rate Matters, Costs Recovered Through Surcharge Represents the portion of costs for a specific program which is being recovered through a surcharge. Demand-side management adjustor charge (DSMAC) Increase in annual wholesale transmission rates The increase in annual wholesale transmission rates as a result of a regulatory action. Rate Matters, Increase in Cost Recovery Revenue increase related to transmission services used for APS's retail customers Rate Matters, Increase in Cost Recovery Retail Rates The increase in annual wholesale transmission rates for retail customers as a result of a regulatory action. Rate Matters, Reduction in Cost Recovery Wholesale Rates Revenue reduction related to transmission services used for wholesale customers The reduction in annual wholesale transmission rates for wholesale customers as a result of a regulatory action. Real Estate Impairment Charge Disclosure [Text Block] Real Estate Impairment Charge Represents the disclosure of real estate impairment charges. Regulatory Accounting [Policy Text Block] Regulatory Accounting Disclosure of accounting policy for regulatory assets and liabilities, which may include the entity's capitalization policy and how impairment of regulatory assets is assessed and recognized. Regulatory Asset Amortization Period Regulatory asset amortization period Represents the amortization period for recovery of the individual regulatory asset in a schedule of regulatory assets. Regulatory Asset Including Deferred Fuel and Purchased Power Regulatory Asset Current The amount for the individual regulatory current asset including deferred fuel and purchased power as itemized in a table of regulatory current assets as of the end of the period. Regulatory assets, current Regulatory liabilities, current The amount for the individual regulatory current liability including deferred fuel and purchased power as itemized in a table of regulatory current liabilities as of the end of the period. Regulatory Liability, Including Deferred Fuel and Purchased Power Regulatory Liability Current Regulatory Matters [Line Items] Regulatory Matters Regulatory Matters Regulatory Matters [Text Block] This element represents Regulatory Matters. Remaining Nuclear Liability Insurance Through Mandatory Industry Wide Retrospective Assessment Program Remaining nuclear liability insurance through mandatory industry wide retrospective assessment program Represents the remaining nuclear liability insurance that is provided through mandatory industry wide retrospective assessment program. Renewable Energy Credits [Member] Renewable Energy Credits or Renewable Energy Certificates ("RECs") are certificates received as proof that one megawatt-hour (MWh) of electricity was generated from a renewable energy resource. RECs can be sold on the open market as a commodity and provide an additional income stream to the energy provider, thus making it a bit more attractive to produce. Renewable energy credits Repayments of loans from subsidiaries Represents the cash inflow associated with the repayments of loans from subsidiaries. Repayments of Loans from Subsidiaries SCHEDULE II - RESERVE FOR UNCOLLECTIBLES Restricted Stock Units RSU and Stock Grants [Member] Represents information pertaining to restricted stock unit awards and stock grants. Restricted stock units and stock grants Retention Units as awarded by the company to their employees as a form of incentive compensation. Retention Units Retention Units [Member] Return Generating Assets [Member] Return-generating assets. Return-generating assets Round Valley System [Member] Represents Round Valley System, a jointly-owned transmission facility of the entity. Round Valley System Palo Verde sale leaseback lessor notes less current maturities (Notes 6 and 20) Sale Leaseback Lessor Notes Variable Interest entity long term debt. Palo Verde sale leaseback lessor notes long-term debt excluding current maturities Palo Verde sale leaseback lessor notes less current maturities (Note 19) Long-term debt excluding current maturities Palo Verde sale leaseback lessor notes Sale Leaseback Lessor Notes [Member] Represents the sale leaseback lessor notes of Palo Verde, a variable interest entity. Accumulated depreciation and amortization Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment Sale Leaseback Transaction Annual Rental Payments if Lease is Extended Annual lease payment if lease is extended Represents the yearly payments to be paid if lease is extended under the lease entered into in connection with the transaction involving the sale of property to another party and the lease of the property back to the seller. Accumulated other comprehensive loss Total accumulated other comprehensive loss Beginning balance Ending balance Accumulated Other Comprehensive Income (Loss), Net of Tax Sale Leaseback Transaction Number of Lease Options Number of options Represents the number of options available under the lease agreement, which the entity has to exercise. Schedule of Asset Retirement Obligations [Table] Information about the carrying amount of a liability for asset retirement obligations. Schedule of Cash Used to Settle Share Based Payment Awards [Table Text Block] Schedule of amount of cash required to settle the payments on restricted stock units Tabular disclosure of aggregate cash paid by the entity during the period to settle equity instruments granted under the equity-based payment arrangements. Schedule of Classification of Deferred Tax Assets and Liabilities [Table Text Block] Tabular disclosure of classification of deferred tax assets and liabilities recognized in the entity's statement of financial position. Net deferred income tax liability recognized on the Consolidated Balance Sheets Net deferred income tax liability recognized on the Balance Sheets Discloses the specific components of significant arrangements in which the entity has agreed to expend funds. Schedule of Commitments and Contingencies [Table] Schedule of Debt Instruments [Table] A table or schedule providing information pertaining to short-term and long-term debt instruments or arrangements, including identification, terms, features, collateral requirements and other information necessary to a fair presentation. Tabular disclosure of the changes in the deferred fuel and purchased power regulatory asset (liability) of regulated entities. Schedule of Deferred Fuel and Purchased Power Regulatory Asset (Liability) [Table Text Block] Schedule of changes in the deferred fuel and purchased power regulatory asset Information about derivative instruments that have credit-risk-related contingent features Tabular disclosure of derivative instruments that have credit-risk-related contingent features. Schedule of Derivative Credit Risk Related Contingent Features [Table Text Block] Schedule of Fair Value Assets and Liabilities Measured on Recurring Basis Unobservable Input Reconciliation [Table Text Block] Changes in fair value for assets and liabilities that are measured at fair value on a recurring basis using Level 3 inputs Tabular disclosure of the fair value measurement of assets and liabilities using significant unobservable inputs (Level 3), a reconciliation of the beginning and ending balances. Derivative Instruments Accumulated Net Unrealized Investment Gain (Loss) [Member] Tabular disclosure of the impact of the reclassifications on quarterly financial data in the annual financial statements. Schedule of Impact of Reclassifications on Quarterly Financial Information [Table Text Block] Impact of the reclassifications on consolidated quarterly financial information Schedule of Income Tax [Table] A table or schedule providing information pertaining to income taxes. Summary of the performance shares granted and the weighted average fair value Tabular disclosure of the number and weighted-average grant date fair value for performance shares. Schedule of Performance Shares Granted and Weighted Average Fair Value [Table Text Block] Accumulated Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net of Tax Accumulated other comprehensive loss Pension and other postretirement benefits Pension and other postretirement benefits Table or schedule disclosing the quarterly financial data in the annual financial statements. The disclosure includes financial information for each fiscal quarter for the current and previous year, including revenues, gross profit, income (loss) before extraordinary items and cumulative effect of a change in accounting principle and earnings per share data. Schedule of Quarterly Financial Information [Table] Schedule of Real Estate Impairment Charges [Table Text Block] Schedule of the impairment charge before income taxes Tabular disclosure of impairment charges recognized during the period for real estate property held for abandonment, exchange or sale. Accumulated Other Comprehensive Income (Loss) [Member] ACCUMULATED OTHER COMPREHENSIVE INCOME (LOSS) Schedule providing information about regulatory matters relating to public utilities. Schedule of Regulatory Matters [Table] Schedule of Restricted Stock Units Award and Stock Grants Activity [Table Text Block] Summary of the status of restricted stock units and stock grants and changes during the year Tabular disclosure of the number and weighted-average grant date fair value for restricted stock units and stock grants that were outstanding at the beginning and end of the year and the number of restricted stock units and stock grants that were granted, vested, or forfeited during the year. Selected Quarterly Financial Information [Line Items] Consolidated quarterly financial information A contractual arrangement to borrow and repay an amount under senior notes at an interest rate of 6.5 percent, due in 2012. Senior Notes 6.5 Percent Due 2012 [Member] 6.50% senior notes due March 1, 2012 Represents the senior unsecured notes maturing at various dates from 2012 through 2041. Senior unsecured notes Senior Unsecured Notes Maturing Through 2041 [Member] Settlement Agreement Base Fuel Rate Proposed Approved base fuel rate (in dollars per kWh) Represents the base rate for fuel and purchased power costs as per the terms of the settlement agreement of a regulatory matter. Settlement Agreement Current Sharing Provision of Fuel and Purchased Power Costs Elimination Elimination of the sharing provision of fuel and purchased power costs Represents the elimination of the current sharing provision of fuel and purchased power costs. Amount of decrease in fuel-related base rates as per the terms of the settlement agreement of a regulatory matter. Settlement Agreement Fuel Related Base Rate Decrease Fuel-related base rate decrease Settlement Agreement, Minimum Equity Infusion Authorization and requirements of equity infusions into APS beginning June 1, 2009 through December 31, 2014 Minimum authorization and requirements of equity infusions into a regulated entity during the period from June 1, 2009 through December 31, 2014, contained in a settlement agreement of a regulatory matter. Minimum amount of reduction of average annual operational expenses from 2010 through 2014 Minimum amount of committed reduction of average annual operational expenses from 2010 through 2014 required by a settlement agreement of a regulatory matter. Settlement Agreement, Minimum Reduction in Average Annual Operational Expenses Derivative instruments Accumulated Other Comprehensive Income (Loss), Cumulative Changes in Net Gain (Loss) from Cash Flow Hedges, Effect Net of Tax Derivative instruments Annual cost recovery due to modifications to the Environmental Improvement Surcharge Settlement Agreement Modifications to EIS Cost Recovery Amount of cost recovery due to modifications to the Environmental Improvement Surcharge (EIS) as per the terms of the settlement agreement of a regulatory matter. Non-fuel base rate increase Amount of increase in non-fuel base rates as per the terms of the settlement agreement of a regulatory matter. Settlement Agreement, Non Fuel Base Rate, Increase Pension and other postretirement benefits Accumulated Defined Benefit Plans Adjustment [Member] Pension and Other Postretirement Benefits Settlement Agreement, Number of Counterparties Number of other parties to the settlement agreement Represents the number of the other parties to the settlement agreement. Deferral of property taxes in all years, if Arizona property tax rates decrease (as a percent) Percentage of deferral of property taxes in all years, if Arizona property tax rates decrease. Settlement Agreement Percentage of Deferral of Property Taxes if Arizona Property Tax Rates Decrease Settlement Agreement Percentage of Deferral of Property Taxes if Arizona Property Tax Rates Increase, Year One Percentage of deferral of property taxes in year one, if Arizona property tax rates increase. Deferral of property taxes in 2012, if Arizona property tax rates increase (as a percent) Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract] Accumulated other comprehensive loss: Accumulated other comprehensive loss: Settlement Agreement Percentage of Deferral of Property Taxes if Arizona Property Tax Rates Increase, Year Three and Thereafter Deferral of property taxes for 2014 and subsequent years, if Arizona property tax rates increase (as a percent) Percentage of deferral of property taxes for year three and thereafter, if Arizona property tax rates increase. Deferred investment tax credit Accumulated Deferred Investment Tax Credit Settlement Agreement Percentage of Deferral of Property Taxes if Arizona Property Tax Rates Increase, Year Two Deferral of property taxes in 2013, if Arizona property tax rates increase (as a percent) Percentage of deferral of property taxes in year two, if Arizona property tax rates increase. Accumulated Other Comprehensive Income (Loss) [Line Items] Changes in accumulated other comprehensive income (loss) including reclassification adjustments, by component: Settlement Agreement Transfer of Cost Recovery to Base Rates Estimated amount of transfer of cost recovery for certain renewable energy projects from the RES surcharge to base rates Estimated amount of transfer of cost recovery for certain renewable energy projects from the RES surcharge to base rates as per the terms of the settlement agreement of a regulatory matter. Accumulated Other Comprehensive Income (Loss) [Table] Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Additional Shares to be Granted if Performance Requirements are Met Additional shares to be granted as retention award if performance requirements are met Represents the number of additional grants to be made during the period on other than stock (or unit) option plans if performance requirements are met. Represents the cash required to settle the payment for grant of equity-based awards other than stock (or unit) option plans. Share Based Compensation Arrangement by Share Based Payment Award, Equity Instruments Other than Options, Cash Required to Settle Payment for Grant Cash required to settle the payment for grant Share based Compensation Arrangement by Share based Payment Award, Equity Instruments Other than Options Increase in Performance in Period Increase in performance factor (in shares) Represents increase in the performance factor made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Represents the weighted average fair value at performance factor date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan). Share based Compensation Arrangement by Share based Payment Award, Equity Instruments Other than Options Increase in Performance in Period Weighted Average Grant Date Fair Value Increase in performance factor (in dollars per share) Number of performance elements criteria that affect the number of shares received after the end of the specified performance period, if performance criteria conditions are met. Share Based Compensation Arrangement by Share Based Payment Award Number of Performance Elements Criteria Number of performance element criteria Aggregate Intrinsic Value Share Based Compensation Arrangement by Share Based Payment Award, Options, Aggregate Intrinsic Value [Abstract] Weighted-Average Exercise Price Share Based Compensation Arrangement by Share Based Payment Award, Options, Weighted Average Exercise Price [Abstract] Share Based Compensation Arrangement by Share Based Payment Award, Options, Weighted Average Remaining Contractual Term [Abstract] Weighted-Average Remaining Contractual Term Exact number of shares issued as a percentage of the target award Represents the number of shares issued as a percentage of the target award. Share Based Compensation Arrangement by Share Based Payment Award Shares Issued as Percentage of Target Award Percentage of awards that are no longer contingent on satisfaction of either a service condition, market condition or a performance condition on the first vesting year from the grant date, thereby giving the employee the legal right to convert the award to shares. Share Based Compensation Arrangement by Share Based Payment Award Vesting Rights Percentage on First Vesting Year from Grant Date Percentage of awards vesting on February 15, 2013 Percentage of awards vesting on February 15, 2014 Percentage of awards that are no longer contingent on satisfaction of either a service condition, market condition or a performance condition on the second vesting year from the grant date, thereby giving the employee the legal right to convert the award to shares. Share Based Compensation Arrangement by Share Based Payment Award Vesting Rights Percentage on Second Vesting Year from Grant Date Percentage of awards that are no longer contingent on satisfaction of either a service condition, market condition or a performance condition on the third vesting year from the grant date, thereby giving the employee the legal right to convert the award to shares. Share Based Compensation Arrangement by Share Based Payment Award Vesting Rights Percentage on Third Vesting Year from Grant Date Percentage of awards vesting on February 15, 2015 Share Based Compensation Arrangements by Share Based Payment Award Options Expiration Term Share Based Compensation Arrangements By Share Based Payment Award Options Expiration Term The period of time, from the grant date until the time at which the share-based [option] award expires. Total capitalization The sum of total shareholder equity and long-term debt less current maturities, including a portion of APS' current maturities of long-term debt. Shareholder Equity and Long Term Debt and Current Maturities Short Term Investments and Other [Member] Short-term investments and other Represents the short-term investments and other. Spent Nuclear Fuel [Member] Liability associated with spent nuclear fuel. Spent nuclear fuel Represents the amount of equity contributed by the parent during the period. Stockholders Equity Contribution from Parent Equity infusion Sun Cor Development Company [Member] SunCor Represents SunCor Development Company, which is a real estate subsidiary of the entity. Superfund-Related Matters Superfund [Abstract] Surety Bonds Terms Surety Bonds, Term Represents the approximate term of surety bonds. Tax expense of Medicare subsidy Tax Expense of Medicare Subsidy [Member] Represents the tax expense of Medicare subsidy. Sum of the carrying amounts as of the balance sheet date of all regulatory assets and other deferred debits that are expected to be recovered through revenue sources (or the normal operating cycle, if longer). Total deferred debits Total Deferred Debits Total deferred debits Total Investments and Other Assets Total investments and other assets Sum of the carrying amounts as of the balance sheet date of all investments and other assets that are expected to be realized in cash, sold, or consumed at a future date that exceeds one year from the balance sheet date. Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. Total investments and other assets Transmission Plant used in connection with transmission of energy. Transmission [Member] Transmission Vegetation Management [Member] Anticipated costs associated with transmission vegetation management to maintain the reliability of overhead transmission lines by minimizing vegetation-caused outages. Transmission vegetation management U.S. Commingled Funds [Member] A professionally managed investment fund of equity securities established by an investment company regulated by the Securities Exchange Commission or a bank regulated by the Office of the Comptroller of the Currency. The investment fund limits it's investments to equity securities located in the United States. US commingled equity funds Additional paid-in capital Additional Paid in Capital, Common Stock US Equity Securities [Member] U.S. Equities Investments made in common and collective trusts that primarily invest in U.S. equities. Represents the Federal Energy Regulatory Commission (FERC). United States Federal Energy Regulatory Commission [Member] FERC Reductions for tax positions of prior years for: Unrecognized Tax Benefits Decreases Resulting from Prior Period Tax Positions [Abstract] The gross amount of decreases in unrecognized tax benefits resulting from settlements with taxing authorities which decreased the effective tax rate. Unrecognized Tax Benefits Decreases Resulting from Settlements with Taxing Authorities that Decreased Effective Tax Rate Net decrease in uncertain tax positions which decreased our effective tax rate Unrecognized Tax Benefits Interest on Income Taxes Benefit Through Effective Tax Rate Net interest benefits through the effective tax rate Represents the net interest benefits recognized through the effective tax rate. Unrecognized Tax Benefits Interest on Income Taxes Receivable Interest income to be received on the overpayment of income taxes for certain adjustments that we have filed, or will file, with the IRS Represents the amount of interest income to be received on the overpayment of income taxes for certain adjustments that the company has filed, or will file, with the IRS. Summary of actual take-or-pay commitments Tabular disclosure of actual unconditional purchase obligations that are not recognized as a liability on the balance sheet, including the nature and significant terms of an unconditional purchase obligation; the amount of the fixed and determinable portion of the obligation as of the date of the latest balance sheet presented in the aggregate and, if determinable, for each of the five succeeding fiscal years; the nature of any variable component of the obligation; the amount purchased under the obligation (for example, the take-or-pay or throughput contract) for the reporting period; and may include the amount of imputed interest necessary to reduce the obligation to present value. Unrecorded Unconditional Actual Purchase, Obligations Disclosure [Text Block] ADDITIONAL PAID-IN CAPITAL Additional Paid-in Capital [Member] Summary of estimated coal take-or-pay commitments Tabular disclosure of expected unconditional purchase obligations that are not recognized as a liability on the balance sheet, including the nature and significant terms of an unconditional purchase obligation; the amount of the fixed and determinable portion of the obligation as of the date of the latest balance sheet presented in the aggregate and, if determinable, for each of the five succeeding fiscal years; the nature of any variable components of the obligation; the amount purchased under the obligation (for example, the take-or-pay or throughput contract) for the reporting period; and may include the amount of imputed interest necessary to reduce the obligation to present value. Unrecorded Unconditional Estimated Purchase, Obligations Disclosure [Text Block] Total net present value of commitments The net present value of an unrecorded unconditional purchase obligation as of the balance sheet date. Unrecorded Unconditional Purchase Obligation, Present Value A contractual arrangement to borrow and repay an amount under unsecured senior notes at an interest rate of 4.5 percent, due in 2042. Unsecured Senior Notes 4.5 Percent Due 2042 [Member] 4.50% unsecured senior notes that mature on April 1, 2042 Additional Collateral, Aggregate Fair Value Additional Cash Collateral in the Event Credit-Risk Related Contingent Features were Fully Triggered Palo Verde Sale Leaseback Variable Interest Entities Statement of Cash Flows Additional Cash Flow Elements, Operating Activities [Abstract] Required payment to Variable Interest Entity Noncontrolling interest holders upon the occurrence of certain events. Variable Interest Entity, Entity Maximum Loss Exposure to Noncontrolling Interests Payment Amount Maximum payment to the VIEs' noncontrolling equity participants upon the occurrence of certain unlikely events Variable Interest Entity, Loss Exposure to Debt Assumed Amount VIE debt to be assumed upon the occurrence of certain unlikely events The amount of exposure to loss, upon the occurrence of certain events, in the form of assumed debt that is already reflected in the Consolidated Balance Sheets, as a result of involvement with the Variable Interest Entity (VIE). Year of Cases [Domain] Year for which the rate cases are filed. Year of Rate Cases [Axis] Year for which the rate cases are filed. Other Comprehensive Income (Loss) before Reclassifications Tax Portion Amount of tax (provision) benefit on other comprehensive income (loss) before reclassifications. Tax (provision) benefit Changes in accumulated other comprehensive income (loss) by component Accumulated Other Comprehensive Income (Loss) [Roll Forward] Tax portion of reclassification adjustments of other comprehensive income (loss). Reclassification from Accumulated Other Comprehensive Income Current Period Tax Portion Tax benefit Tabular disclosure of derivatives, other financial assets and liabilities that are subject to offsetting, including master netting arrangements. Offsetting Assets and Liabilities [Table Text Block] Schedule of the entity's fair value of risk management activities reported on a gross basis and the impacts of offsetting Offsetting Assets and Liabilities [Line Items] Fair value of risk management activities reported on gross basis and the impacts of offsetting Assets and Liabilities Offsetting Derivative Assets Liabilities, Net [Abstract] Derivative Fair Value of Derivative Assets (Liability), Net Represents the fair value of derivative asset, net of liability, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position. Gross Recognized Derivatives Derivative Fair Value Gross Asset (Liability), Net Represents the fair value of assets (liabilities) associated with derivative instrument, presented on a gross basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position. Amounts Offset Represents the fair value of derivative asset net of liability, presented on a net basis even when the derivative instrument is subject to master netting arrangements and qualifies for net presentation in the statement of financial position. Net Recognized Derivatives Derivative Asset (Liability), Fair Value, Net Other Derivative Collateral Obligation Right to Return Reclaim Cash Represents the amount of the obligation to return cash collateral and right to reclaim cash collateral under master netting arrangements that have not been offset against net derivative instrument positions. Fair Value Measurement Inter Level Transfers Amount Transfers in or out of Level 1 to or from any other hierarchy level The amount of the transfers of assets or liabilities measured on a recurring basis out of Level 1 of the fair value hierarchy into any other hierarchy level. Benefit payments The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a decrease to plan assets. Defined Benefit Plan Change in Fair Value of Plan Assets, Benefits Paid Represents information pertaining to the contaminated groundwater wells. Contaminated Groundwater Wells [Member] Contaminated groundwater wells Income tax expense associates with the VIE's Income Tax Expense Benefit Attributable to Non Controlling Interests The sum of the current income tax expense or benefit attributable to non-controlling interests. Other Other Prior Period Adjustment Represents information pertaining to the other prior period adjustment. Pollution Control Revenue Refunding Bonds, 1994 Series A [Member] Pollution Control Revenue Refunding Bonds, 1994 Series A A contractual arrangement to borrow and repay an amount under pollution control revenue refunding bonds, 1994 series A. Arizona Renewable Energy Standard and Tariff Annual Implementation Plan 2014 to 2018 [Member] RES implementation plan covering 2014-2018 timeframe Represents information pertaining to the annual RES implementation plan covering the 2014-2018 timeframe. Retired power plant costs Represents the regulatory asset under Retired power plant costs. Retired Power Plant Costs [Member] Rate Matter Percentage of Sale of Distributed Energy Systems Output at Market Price for Installing New Rooftop Solar System Percentage of sale of distributed energy system's output at a market-based price for installing new rooftop solar system to all new residential customers Represents the percentage of sale of the distributed energy system's output at a market-based price for installing a new rooftop solar system to all new residential customers. Income Tax Receivable that Reclassified from Long Term to Short Term Income tax receivable that will be reclassified from long term to short-term Represents income tax receivable that will be reclassified from long term to short-term. Lost Fixed Cost Recovery [Member] Lost fixed cost recovery Represents the regulatory asset under lost fixed recovery mechanisms. Transmission Cost Adjustor [Member] Transmission cost adjustor Represents the regulatory asset under transmission cost adjustor mechanisms. Estimated contributions The reporting scenario used to indicate financial results estimated for a future period. Scenario Estimated [Member] Represents the expenditures made during the period to acquire and/or expand fixed assets. Capital expenditures made to expand the existing earnings capacity of our assets are considered expansion capital expenditures, not maintenance capital. Capital Expenditures Capital expenditures Schedule detailing information related to shareholders' equity comprised of portions attributable to the parent entity and noncontrolling interest, including other comprehensive income. Statement of Stock holders Equity [Table] Statement of Stock holders Equity [Line Items] Changes in equity Changes in Equity Defined Benefit Plan Employer Contributions [Abstract] Contributions Minimum Contributions under MAP-21 Defined Benefit Plan Estimated Future Minimum Employer Contributions under Act [Abstract] 2014 Represents the amount of employer's minimum estimated contributions expected to be paid to the plan in the current fiscal period. Defined Benefit Plans Estimated Minimum Future Employer Contributions under the Act in Current Fiscal Year 2015 Represents the amount of employer's minimum estimated contributions expected to be paid to the plan in the second fiscal year following the latest fiscal year. Defined Benefit Plans Estimated Minimum Future Employer Contributions under the Act in Year Two 2016 Amount of employer's best estimate of contributions expected to be paid to the plan during the third fiscal year beginning after the date of the latest statement of financial position. Defined Benefit Plans Estimated Future Employer Contributions in Year Three Public Utilities Regulatory, Regulatory Matters [Axis] Represents information by various regulatory matters. Represents various regulatory matters. Public Utilities Regulatory, Regulatory Matters [Domain] Represents information pertaining to the 2008 General Retail Rate Case On-Going Impacts. General Retail Rate Case 2008 on Going Impact [Member] 2008 General Retail Rate Case On-Going Impacts Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to reconcile net income to net cash provided by operating activities: Adjustments to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities [Abstract] Regulatory Matters General Retail Rate Case 2008 on Going Impact [Abstract] 2008 General Retail Rate Case on-going impacts 2016 Represents the amount of employer's minimum estimated contributions expected to be paid to the plan in the third fiscal year following the latest fiscal year. Defined Benefit Plans Estimated Minimum Future Employer Contributions under Act in Year Three Defined Benefit Plan Assumptions used in Calculating Benefit Obligation and Net Periodic Benefit Cost Discount Rate Discount rate (as a percent) Represents the interest rate used to adjust for the time value of money for the plan. Rate of compensation increase (as a percent) Represents the expected rate of compensation increase (for pay-related plans). Defined Benefit Plan Assumptions used in Calculating Benefit Obligation and Net Periodic Benefit Cost Rate of Compensation Increase Initial health care cost trend rate (as a percent) Defined Benefit Plan Assumptions used in Calculating Benefit Obligation and Net Periodic Benefit Cost Rate of Initial Health Care Cost Trend Represents the expected rate of initial health care cost trend. Ultimate health care cost trend rate (as a percent) Represents the ultimate trend rate for health care costs. Defined Benefit Plan Assumptions used in Calculating Benefit Obligation and Net Periodic Benefit Cost Ultimate Health Care Cost Trend Rate Represents the period after which the ultimate health care cost trend rate is expected to be reached. Number of years to ultimate trend rate Defined Benefit Plan Assumptions used in Calculating Benefit Obligation and Net Periodic Benefit Cost Period after which Rate Reaches Ultimate Trend Rate Represents the information pertaining to other equity securities. Other Equity Securities Other Equity Securities [Member] Pollution Control Revenue Refunding Bonds 1994 Series C [Member] Pollution Control Revenue Refunding Bonds, 1994 Series C A contractual arrangement to borrow and repay an amount under pollution control revenue refunding bonds, 1994 series C. The increase (decrease) during the reporting period in the amount due to contractual obligations for fuel and purchased power commitments. Increase (Decrease) in Unrecorded Unconditional Purchase Obligation Decrease in contractual obligations for fuel and purchased power commitments Represent information pertaining to New Mexico Tax Matter. New Mexico Tax Matter [Member] New Mexico Tax Matter Coal severance surtax, penalty, and interest Represent information pertaining to total amount of coal severance surtax, penalty, and interest related to coal supplied under the coal supply agreement. Loss Contingency Coal Severance Surtax Penalty and Interest Loss Contingency Assessment Share Share of the assessment Represent information pertaining to share of the assessment. Represents information pertaining to number of modest charges on new solar customers with a mechanism to return all incremental revenue collected from such charges to customers. Number of Modest Charges on New Solar Customers Number of modest charges on new solar customers Increase (decrease) in Income Taxes Receivable Non current Change in long term income tax receivable The increase (decrease) during the reporting period in non-current portion of income taxes receivable, which represents the amount due from tax authorities for refunds of overpayments or recoveries of income taxes paid. Change in long-term income tax receivable Future payments with respect long-term deferred tax liabilities Represent the expected future payments with respect to long-term deferred tax liabilities. Expected Payment for Long Term Deferred Tax Liabilities Period over which Deferred Income Tax Liability would Have Been Repaid Period over which deferred income tax liability would have been repaid Represents the period over which the deferred income tax liability would have been repaid. Phase in Period of Corporate Income Tax Rate Reductions Phase-in period of corporate income tax rate reductions beginning in 2014 Phase-in period of corporate income tax rate reductions beginning in 2014 by Arizona enacted legislation (H.B. 2001). Grant 2013 [Member] 2013 grant Represents the grant of equity based awards made in 2013. Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options [Abstract] Stocks granted and the weighted average fair value Share Based Compensation Arrangement by Share Based Payment Award Equity Instruments Other than Options Unit Grants in Period Units granted (in shares) The number of units granted during the period on other than stock (or unit) option plans. Finite Lived Intangible Asset [Abstract] Intangible Assets Line of Credit Facility, Letters of Credit Support, Maximum Borrowing Capacity Maximum letters of credit support available under credit facility Represents the maximum borrowings available for the issuances of letters of credit under the terms of line of credit facility. Total Long Term Debt Less Current Maturities Total long-term debt less current maturities Sum of the carrying values as of the balance sheet date of total long-term debt, which is debt initially having maturities due after one year from the balance sheet date or beyond the operating cycle, if longer, but excluding the portions thereof scheduled to be repaid within one year or the normal operating cycle, if longer plus capital lease obligations due to be paid more than one year after the balance sheet date. Preferred Stock Par or Stated Value Per Share 1 Par value of type 1 preferred stock authorized (in dollars per share) Face amount or stated value per share of nonredeemable preferred stock type 1 (or preferred stock redeemable type 1 solely at the option of the issuer); generally not indicative of the fair market value per share. Preferred Stock Par Or Stated Value Per Share 2 Par value of type 2 preferred stock authorized (in dollars per share) Face amount or stated value per share of nonredeemable preferred stock type 2 (or preferred stock redeemable type 2 solely at the option of the issuer); generally not indicative of the fair market value per share. Preferred Stock Par Or Stated Value Per Share 3 Par value of type 3 preferred stock authorized (in dollars per share) Face amount or stated value per share of nonredeemable preferred stock type 3 (or preferred stock redeemable type 3 solely at the option of the issuer); generally not indicative of the fair market value per share. Rate Matter Estimated Monthly Collection Due to Charge on Future Customers who Install Rooftop Solar Panels Estimated monthly collection due to charge on future customers who install rooftop solar panels Represents the amount of estimated monthly collection due to charge on future customers who install rooftop solar panels under order issued on net metering proposal. Southern California Edison Company [Member] SCE Represents information related to Southern California Edison Company. Represents the amount of acquisition adjustments to property, plant, and equipment recognized as of the acquisition date. Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Property Plant and Equipment Acquisition Adjustment Acquisition adjustment Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Property Plant and Equipment Construction Work in Progress Construction work in progress Represents the amount of construction work in progress of property, plant, and equipment recognized as of the acquisition date. Decommissioning obligations Represents the amount of decommissioning obligations, assumed at the acquisition date. Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Decommissioning Obligations Represents the amount of mine reclamation obligations, assumed at the acquisition date. Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Mine Reclamation Obligations Mine reclamation obligations Other various liabilities Represents the amount of other various liabilities, assumed at the acquisition date. Business Combination Recognized Identifiable Assets Acquired and Liabilities Assumed Other Various Liabilities Four Corners Cost Deferral [Member] Four Corners cost deferral Represents the regulatory asset under Four Corners cost deferral. Unsecured Senior Notes 4.7 Percent Due 2044 [Member] 4.70% unsecured senior notes that mature on January 15, 2044 A contractual arrangement to borrow and repay an amount under the unsecured senior notes at an interest rate of 4.7 percent, due in 2044. Palo Verde - Morgan System Represents Palo Verde - Morgan System, a jointly-owned transmission facility of the entity. Palo Verde Morgan System [Member] Asset Retirement Obligation Assumed Decommissioning Obligation Assumed SCE's obligation Represents the amount of asset retirement obligations decommissioning obligation assumed in SCE acquisition during the period. Federal and State Loss Carryforwards Which Will Begin to Expire in 2018 Amount of federal and state loss carryforwards which will begin to expire in 2018 Represents the amount of other federal and state loss carryforwards, which expires in 2018. Rate Matter Charge on Future Customers who Install Rooftop Solar Panels Charge on future customers who install rooftop solar panels (in dollars per kWh) Represents the Charge on future customers who install rooftop solar panels under order issued on net metering proposal. Transmission Termination Agreement Power Capacity Rights Assigned to Third Parties Capacity rights over the Arizona Transmission System assign to third-parties Represents the capacity rights over the Arizona Transmission System assigned to third-parties under negotiation of alternate arrangement. Transmission Termination Agreement Power Capacity Rights Related to Marketing and Trading Group for Transmission of Additional Power Receive Assigned to Third Parties Capacity rights related to marketing and trading group for transmission of the additional power received assign to third-parties Represents the capacity rights related to marketing and trading group for transmission of the additional power received assigned to third-parties under negotiation of alternate arrangement. Transmission Termination Agreement Net Receipt Due to Negotiation of Alternate Arrangement Net receipt due to negotiation of alternate arrangement Represents the amount of net receipt due to negotiation of alternate arrangement. Rate Matter Recovery Period Period beginning March 1, 2012, over which the costs will be recovered Represents the period over which the amount of APS's energy efficiency and demand side management program costs will be recovered by the then existing DSMAC. Represents total entitlement acquired by the entity. Total Entitlement Acquired Total Entitlement Represents the percentage of share of the cost of control acquired by the entity. Percentage of Share of Cost of Control Share of Cost of Control of Four Corners Units 4 and 5 Accrued taxes and income tax receivable The net increase (decrease) during the reporting period of all taxes owed but not paid, including income, property, other taxes and income tax receivable. Increase (Decrease) in Accrued Taxes Payable and Income Taxes Receivable Residential Customers Rate Case Filing [Member] Residential customers rate case filing Represents information pertaining to residential customers rate case filing. Business Acquisition Equity Interest Value Deferred Deferral balance related to the acquisition of SCE's interest in Units 4 and 5 and the closure of Four Corners Units 1-3 Represents the value of equity interests (such as common shares, preferred shares, or partnership interest) of the acquired entity deferred. Defined Benefit Plans Estimated Minimum Future Employer Contributions under Act Minimum contributions under MAP-21 Represents the amount of employer's minimum estimated contributions expected to be paid to the plan. Amount of employer's best estimate of contributions expected to be paid to the plan during the next three fiscal year beginning after the date of the latest statement of financial position. Defined Benefit Plans Estimated Future Employer Contributions in Next Three Fiscal Year Expected employer's contributions Number of Entities Alleged Number of alleged entities Represents the number of alleged entities under non-public preliminary investigations. Represents the information pertaining to the number of Reliability Standard Requirements violations in which the company is alleged. Reliability Standard Requirements Violations Number Number of Reliability Standard Requirements Violations alleged Increase (Decrease) in Deferred Income Taxes Due to Regulation Adoption Increase (decrease) in deferred income taxes due to adoption of regulations The increase (decrease) during the reporting period in the account that represents the temporary difference that results from Income or Loss that is recognized for accounting purposes but not for tax purposes and vice versa, due to the adoption of regulations. Increase (Decrease) in Deferred Income Taxes Due to Rate Changes Decrease in long term deferred tax liability due to rate changes The increase (decrease) during the reporting period in the account that represents the temporary difference that results from Income or Loss that is recognized for accounting purposes but not for tax purposes and vice versa, due to rate changes. Represents the estimated change in the total amount of the unrecognized tax benefit (that will significantly increase or decrease within twelve months of the balance sheet date) for a tax position taken. Significant Change in Unrecognized Tax Benefits Decrease in uncertain tax positions Common and Collective Trusts Fixed Income Securities [Member] FIXED INCOME Investments made in common and collective trusts that primarily invest in fixed income securities. Asset Retirement Obligation Total The carrying amount of a liability for an asset retirement obligation including current and long-term amounts. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees. Asset retirement obligations at the beginning of year Asset retirement obligations at the end of year Deferred Tax Assets Net Current Value Amount after the allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and carryforwards expected to be realized or consumed within one year or operating cycle, if longer. Deferred income taxes Deferred Income Tax Expenses Benefits Amount of deferred income tax expenses (benefits) pertaining to income (loss) from continuing operations. Total deferred Demand Side Management Adjustor Charge 2014 [Member] 2014 DSMAC Represents the DSMAC program which permits a surcharge for 2014 as part of customer bills to recover approved amounts for use in energy efficiency projects. Pollution Control Revenue Refunding Bonds 2009 Series A, Series D and Series E [Member] Pollution Control Revenue Refunding Bonds, 2009 Series A, D and E A contractual arrangement to borrow and repay an amount under Pollution Control Revenue Refunding Bonds, 2009 series A, D and E. Represents the percentage of possible impact on average bill to residential customers. Percentage of Possible Impact on Average Bill to Residential Customers Percentage of possible impact on average bill to residential customers Net Metering [Member] Net Metering Represents information pertaining to the proposed solution to the ACC to fix the cost shift brought by current net metering rules. Pollution Control Revenue Refunding Bonds 2009 Series B and Series C [Member] Pollution Control Revenue Refunding Bonds, 2009 Series B and C A contractual arrangement to borrow and repay an amount under Pollution Control Revenue Refunding Bonds, 2009 Series B and C. Deferred Property Taxes [Member] Deferred property taxes Represents information pertaining to deferred property taxes. Sale Leaseback Transaction Period [Axis] Represents information pertinent to sale and leaseback period. Represents details pertaining to sale and leaseback period. Sale Leaseback Transaction Period [Domain] Sale Leaseback Transaction Period Through 2023 [Member] Through 2023 Represents information pertaining to sale and leaseback period through 2023. Sale Leaseback Transaction Period Through 2033 [Member] Represents information pertaining to sale and leaseback period through 2033. Through 2033 Sale Leaseback Transaction Period 2016 Through 2023 [Member] Period 2016 through 2023 Represents information pertaining to sale and leaseback period 2016 through 2023. Sale Leaseback Transaction Period 2024 Through 2033 [Member] Period 2024 through 2033 Represents information pertaining to sale and leaseback period 2024 through 2033. Sale Leaseback Transaction Number of Leases under which Assets Retained Through Specified Period Number of leases under which assets are retained Represents the number of leases under which assets are retained through a specified period. Reliability Standard Requirements Number Neither Admitted Nor Denied Violations In Settlement Number of Reliability Standard Requirements neither admitted nor denied violations in settlement Represents information pertaining to the number of Reliability Standard Requirements which neither admitted nor denied violations in settlement. Reliability Standard Requirements Litigation Settlement Amount Required to be Paid in Equal Parts Civil penalty amount required to be paid in equal parts Amount of judgment or settlement awarded to (against) the entity in respect of litigation, which is required to be paid in equal parts. Reliability Standard Requirements Litigation Settlement Amount Offset in Exchange for Completing Certain Reliability Enhancements Civil penalty amount offset in exchange for completing certain reliability enhancements Represents the settlement amount offset in exchange for completing certain reliability enhancements. Palo Verde Nuclear Facilities and Certain other Generation Transmission and Distribution Assets [Member] Palo Verde Represents information pertaining to Palo Verde nuclear facilities and certain other generation, transmission and distribution assets. Four Corners Units 1 Through 3 [Member] Four Corners Units 1-3 Represents information pertaining to Four Corners Units 1 through 3. Asset Retirement Obligation Amount of Update on Account of Decommissioning Study Amount of update on account of decommissioning study Represents the amount of update to asset on account of decommissioning study. 2014 RES Represents the RES program, which permits a surcharge for 2014 as a part of customer bills to recover approved amounts for use in renewable energy projects. Arizona Renewable Energy Standard and Tariff 2014 [Member] Rate Matter Capacity from A Z Sun Residential Projects Capacity of APS-owned residential solar AZ Sun projects (in MW) Represents the capacity of APS-owned residential solar AZ Sun projects. Rate Matter Cap Percentage of Retail Revenue Percentage of retail revenues Represents information pertaining to cap percentage of retail revenues. Sale Leaseback Transaction Lease Period Lease period Represents the period of lease entered into in connection with the transaction involving the sale of property to another party and the lease of the property back to the seller. Dividends Declared but Not Yet Paid Dividends declared but not yet paid Represents the future cash outflow to pay for dividends declared but not yet paid. A contractual arrangement to borrow and repay an amount under 2009 series A bonds. Series A Bonds 2009 [Member] 2009 series A bonds Series D and Series E Bonds 2009 [Member] 2009 series D and series E bonds A contractual arrangement to borrow and repay an amount under 2009 series D and series E bonds. Series B and Series C Bonds 2009 [Member] 2009 series B and series C bonds A contractual arrangement to borrow and repay an amount under 2009 series B and series C bonds. Equity Lessors Sale Leaseback Letter of Credit [Member] Equity Lessors in Palo Verde sale leaseback transactions A document typically issued by a financial institution which acts as a guarantee of payment to a beneficiary, or as the source of payment for a specific transaction to support certain equity lessors in sales leaseack transactions as of the reporting date. Natural Gas Tolling Letter of Credit [Member] Natural gas tolling contract obligations A document typically issued by a financial institution which acts as a guarantee of payment to a beneficiary, or as the source of payment for a specific transaction to natural gas tolling contract obligations as of the reporting date. Letters of Credit Expiring in 2015 [Member] Letters of credit expiring in 2015 Represents the credit facility expiring in 2015. Letters of Credit Expiring in 2016 [Member] Letters of credit expiring in 2016 Represents the credit facility expiring in 2016. Number of Letters of Credit Expiring Number of letters of credit expiring Represents the number of letters of credit expiring. All other Other Segments [Member] Allocated Share-based Compensation Expense Compensation cost that has been charged against income Allowance for Doubtful Accounts Receivable, Current Allowance for doubtful accounts Allowance for borrowed funds used during construction Allowance for Funds Used During Construction, Investing Activities Allowance for Funds Used During Construction Allowance for Funds Used During Construction, Policy [Policy Text Block] Reserve for uncollectibles. Allowance for Doubtful Accounts [Member] Amortization expense Amortization of Intangible Assets Amortization of regulatory assets Amortization of Regulatory Asset Options to purchase shares of common stock outstanding excluded from computation of diluted earnings per share due to its antidilutive effect Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount Asset Retirement Obligations Asset Retirement Obligation Disclosure [Text Block] Accretion expense Asset Retirement Obligation, Accretion Expense Changes attributable to: Asset Retirement Obligation [Abstract] Liabilities for asset retirements Asset Retirement Obligations, Noncurrent Liabilities for asset retirements (Note 16) Asset Retirement Obligations Asset Retirement Obligation Costs [Member] Asset retirement obligations Estimated cash flow revisions Asset Retirement Obligation, Revision of Estimate Liabilities for asset retirements Asset retirement obligations at the beginning of year Asset retirement obligations at the end of year Asset Retirement Obligation Change in asset retirement obligations Asset Retirement Obligation, Roll Forward Analysis [Roll Forward] Settlements Asset Retirement Obligation, Liabilities Settled Asset retirement obligations, current Asset Retirement Obligation, Current Liabilities for asset retirements Assets Assets, Fair Value Disclosure [Abstract] TOTAL ASSETS Assets Total assets Assets Total assets Assets Assets, Fair Value Disclosure CURRENT ASSETS Current assets Assets, Current [Abstract] ASSETS Assets Assets [Abstract] Total Assets Assets, Total [Member] Assets Disposal Group, Including Discontinued Operation, Assets Total current assets Assets, Current Current Assets - Assets held for sale Disposal Group, Including Discontinued Operation, Assets, Current Fair value of APS's nuclear decommissioning trust fund assets Available-for-sale Securities [Table Text Block] Unrealized Gains Available-for-sale Securities, Accumulated Gross Unrealized Gain, before Tax Unrealized Losses Available-for-sale Securities, Accumulated Gross Unrealized Loss, before Tax Less than one year Available-for-sale Securities, Debt Maturities, Next Twelve Months, Fair Value 5 years - 10 years Available-for-sale Securities, Debt Maturities, Year Six Through Ten, Fair Value Fair value of fixed income securities, summarized by contractual maturities Available-for-sale Securities, Debt Maturities, Fair Value, Fiscal Year Maturity [Abstract] Greater than 10 years Available-for-sale Securities, Debt Maturities, after Ten Years, Fair Value 1 year - 5 years Available-for-sale Securities, Debt Maturities, Year Two Through Five, Fair Value Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds Available-for-sale Securities, Gross Realized Gain (Loss), Disclosures [Abstract] Realized losses Available-for-sale Securities, Gross Realized Losses Realized gains Available-for-sale Securities, Gross Realized Gains Balance Sheet Location [Axis] Balance Sheets Balance Sheet Related Disclosures [Abstract] Balance Sheet Location [Domain] Description of Business and Basis of Presentation Basis of Accounting, Policy [Policy Text Block] Business Acquisition [Axis] Acquisition Business Acquisition [Line Items] Ownership interest acquired Business Acquisition, Percentage of Voting Interests Acquired Business Acquisition, Acquiree [Domain] Purchase price Business Combination, Consideration Transferred Plant-in-service Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment Capitalized lease obligations Capital Lease Obligations [Member] Accrued capital expenditures Capital Expenditures Incurred but Not yet Paid Nuclear Fuel Capitalization and Amortization of Fuel Costs, Policy [Policy Text Block] Cash and Cash Equivalents Cash and Cash Equivalents, Policy [Policy Text Block] NET INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS Cash and Cash Equivalents, Period Increase (Decrease) Estimated net loss before income taxes to be reclassified from accumulated other comprehensive income Cash Flow Hedge Gain (Loss) to be Reclassified within Twelve Months Cash and cash equivalents CASH AND CASH EQUIVALENTS AT BEGINNING OF PERIOD CASH AND CASH EQUIVALENTS AT END OF PERIOD Cash and Cash Equivalents, at Carrying Value Cash Equivalents Cash and Cash Equivalents, Fair Value Disclosure Cash and Cash Equivalents Cash and Cash Equivalents [Abstract] Cash and cash equivalent funds Cash and Cash Equivalents [Member] Non-cash financing activities: Significant non-cash investing and financing activities: Cash Flow, Noncash Investing and Financing Activities Disclosure [Abstract] Variable Interest Entity, Classification [Domain] Cash Collateral Posted Collateral Already Posted, Aggregate Fair Value Commercial Paper Commercial Paper [Member] Commercial paper (Note 5) Commercial Paper Commitments and Contingencies. COMMITMENTS AND CONTINGENCIES (SEE NOTES) Commitments and Contingencies Commitments and Contingencies Commitments and Contingencies Disclosure [Text Block] Option Contracts Commodity Option [Member] Commodity Contracts Commodity Contract [Member] COMMON STOCK (Note 7) Common Stock Common Stock [Member] COMMON STOCK Common stock, no par value; authorized 150,000,000 shares, 110,430,456 and 110,280,703 issued at respective dates Common stock Common Stock, Value, Issued Common stock, issued shares Balance at the beginning of the period (in shares) Balance at the end of the period (in shares) Common Stock, Shares, Issued DIVIDENDS DECLARED PER SHARE (in dollars per share) Common Stock, Dividends, Per Share, Declared Total common stock Common stock Common Stock, Value, Outstanding Common stock, authorized shares Common Stock, Shares Authorized Common stock, par value (in dollars per share) Common Stock, No Par Value Retirement Plans and Other Benefits Other Income and Other Expense Component of Other Expense, Nonoperating [Abstract] DEFERRED TAX ASSETS Components of Deferred Tax Assets [Abstract] Components of income tax expense Components of Income Tax Expense (Benefit), Continuing Operations [Abstract] Components of the net deferred income tax liability Components of Deferred Tax Assets and Liabilities [Abstract] DEFERRED TAX LIABILITIES Components of Deferred Tax Liabilities [Abstract] COMPREHENSIVE INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS Total comprehensive income attributable to common shareholders Net income attributable to common shareholders Comprehensive Income (Loss), Net of Tax, Attributable to Parent Changes in Accumulated Other Comprehensive Loss COMPREHENSIVE INCOME ATTRIBUTABLE TO COMMON SHAREHOLDER Total comprehensive income (loss) COMPREHENSIVE INCOME Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest Changes in Accumulated Other Comprehensive Loss Comprehensive Income (Loss) Note [Text Block] COMPREHENSIVE INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS Comprehensive Income [Member] COMPREHENSIVE INCOME ATTRIBUTABLE TO COMMON SHAREHOLDER Concentration of risk with two counterparties, as a percentage of risk management assets Concentration Risk, Percentage CONDENSED STATEMENTS OF INCOME CONDENSED BALANCE SHEETS CONDENSED STATEMENTS OF CASH FLOWS Condensed Financial Statements, Captions [Line Items] SCHEDULE I - CONDENSED FINANCIAL INFORMATION OF REGISTRANT Condensed Financial Information of Parent Company Only Disclosure [Text Block] Construction work in progress Construction in Progress, Gross Corporate debt Corporate Debt Securities [Member] Fuel and purchased power Cost of Goods Sold, Electric Depreciation and amortization Cost of Services, Depreciation and Amortization Fuel and purchased power Cost of Sales [Member] Accrued unbilled revenues Costs in Excess of Billings, Current OPERATING EXPENSES Operating Expenses Costs and Expenses [Abstract] Total Operating expenses Costs and Expenses Credit Facility [Axis] Credit Facility [Domain] State Current State and Local Tax Expense (Benefit) Current: Current Income Tax Expense (Benefit), Continuing Operations [Abstract] Federal Current Federal Tax Expense (Benefit) Total current Current Income Tax Expense (Benefit) Customer advances Customer Advances for Construction Customer deposits Customer Deposits, Current Designated as Hedging Instruments Designated as Hedging Instrument [Member] Principal balance repaid Debt Instrument, Decrease, Repayments (Deprecated 2013-01-31) Repurchase debt amount Debt Instrument, Repurchase Amount Long-Term Debt and Liquidity Matters Debt Instrument [Line Items] Schedule of Long-term Debt Instruments [Table] Notes issued Debt Instrument, Face Amount Carrying Amount Long-term debt Long-term debt Debt and Capital Lease Obligations Long-Term Debt and Liquidity Matters Principal balance repaid Debt Instrument, Repurchased Face Amount Total Long-term debt redemption Long-term Debt, Gross Debt Instrument [Axis] Debt Instrument, Name [Domain] Unamortized discount Debt Instrument, Unamortized Discount Fixed income securities Debt Securities [Member] Debt Instrument, Unamortized Premium Unamortized premium Interest rate (as a percent) Debt Instrument, Interest Rate, Stated Percentage Notes issued Debt Instrument, Increase, Additional Borrowings (Deprecated 2013-01-31) Debt discount, premium and expense Debt Related Commitment Fees and Debt Issuance Costs Interest Rates, high end of range (as a percent) Debt Instrument, Interest Rate, Stated Percentage Rate Range, Maximum Interest Rates, low end of range (as a percent) Debt Instrument, Interest Rate, Stated Percentage Rate Range, Minimum Estimated fair value of long-term debt, including current maturities Debt Instruments [Abstract] Nuclear decommissioning trust (Note 13) Nuclear decommissioning trust Fair Value Total Nuclear decommissioning trust (Notes 13) Decommissioning Fund Investments, Fair Value Total deferred credits and other Deferred Credits and Other Liabilities DEFERRED CREDITS AND OTHER Deferred credits and other Deferred Credits and Other Liabilities [Abstract] Equity-Based Arrangements, Individual Contracts, Type of Deferred Compensation [Axis] Federal Deferred Federal Income Tax Expense (Benefit) Deferred: Deferred Income Tax Expense (Benefit), Continuing Operations [Abstract] DEFERRED DEBITS Deferred Costs [Abstract] Deferred income taxes Income from continuing operations Deferred Total deferred Deferred Income Tax Expense (Benefit) Deferred gains on utility property Deferred Gain (Loss) on Early Extinguishment of Debt [Member] Income taxes - allowance for funds used during construction ("AFUDC") equity Income taxes - change in rates Deferred Income Tax Charge [Member] State Deferred State and Local Income Tax Expense (Benefit) Deferred income taxes - net Deferred Tax Assets, Net Risk management activities Deferred Tax Assets, Derivative Instruments Net deferred income tax liability recognized on the Consolidated Balance Sheets Deferred Tax Assets, Net, Classification [Abstract] Other Deferred Tax Assets, Other Deferred income taxes Current asset (liability) Current deferred income taxes Deferred income taxes Deferred Tax Assets, Net of Valuation Allowance, Current Deferred income taxes (Notes 4 and S-1) Total deferred tax assets Deferred Tax Assets, Net of Valuation Allowance Pension and other postretirement liabilities Deferred Tax Assets, Tax Deferred Expense, Compensation and Benefits Deferred income taxes Deferred Tax Assets, Net of Valuation Allowance, Noncurrent Other Deferred Tax Liabilities, Other Deferred income taxes Deferred Tax Liabilities, Net, Noncurrent Deferred income taxes Long-term liability Plant-related Deferred Tax Liabilities, Property, Plant and Equipment Total deferred tax liabilities Deferred Tax Liabilities, Net Deferred income taxes Deferred Tax Liabilities, Net, Current Risk management activities Deferred Tax Liabilities, Derivatives Estimated amounts that will be amortized from accumulated other comprehensive loss and regulatory assets into net periodic benefit cost in 2014 Defined Benefit Plan, Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year [Abstract] 2018 Defined Benefit Plan, Expected Future Benefit Payments, Year Five 2014 Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year 2013 Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year Defined Benefit Plan, Benefit Obligation Benefit obligation at the beginning of the period Benefit obligation at the end of the period Defined Benefit Plan, Amounts Recognized in Balance Sheet Net amount recognized Amortization of prior service cost Defined Benefit Plan, Amortization of Prior Service Cost (Credit) Weighted-average assumptions used to determine benefit obligations Defined Benefit Plan, Assumptions Used in Calculations [Abstract] 2016 Defined Benefit Plan, Expected Future Benefit Payments, Year Three 2015 Defined Benefit Plan, Expected Future Benefit Payments, Year Two Transition obligation Defined Benefit Plan, Future Amortization of Transition Obligation (Asset) Net actuarial loss Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax Effect of 1% decrease on service and interest cost components of net periodic other postretirement benefit costs Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components Defined Benefit Plan, Target Plan Asset Allocations Range Minimum Target allocation, minimum (as a percent) Expected employer's contributions Defined Benefit Plan, Estimated Future Employer Contributions [Abstract] Actuarial (gain) loss Defined Benefit Plan, Actuarial Gain (Loss) Discount rate (as a percent) Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate Expected long-term return on plan assets Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets Years 2019-2023 Defined Benefit Plan, Expected Future Benefit Payments, Five Fiscal Years Thereafter 2017 Defined Benefit Plan, Expected Future Benefit Payments, Year Four Amortization of net actuarial loss Defined Benefit Plan, Amortization of Gains (Losses) Defined Benefit Plan, Target Plan Asset Allocations Range Maximum Target allocation, maximum (as a percent) Amounts recognized on the Consolidated Balance Sheets Defined Benefit Plan, Amounts Recognized in Balance Sheet [Abstract] Discount rate (as a percent) Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Discount Rate Effect of 1% decrease on the accumulated other postretirement benefit obligation Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation Defined Benefit Plan, Assets, Target Allocations [Abstract] Target asset allocation Total amounts estimated to be amortized from accumulated other comprehensive loss and regulatory assets in 2014 Defined Benefit Plan, Amount to be Amortized from Accumulated Other Comprehensive Income (Loss) Next Fiscal Year Prior service cost (credit) Defined Benefit Plan, Future Amortization of Prior Service Cost (Credit) Net actuarial loss Defined Benefit Plan, Future Amortization of Gain (Loss) Retirement Plans and Other Benefits Defined Benefit Plan Disclosure [Line Items] Amortization of transition obligation Defined Benefit Plan, Amortization of Transition Obligations (Assets) Actual return on plan assets Defined Benefit Plan, Actual Return on Plan Assets Details related to accumulated other comprehensive loss Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract] Rate of compensation increase (as a percent) Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Rate of Compensation Increase 2014 Defined Benefit Plan, Expected Future Benefit Payments, Next Twelve Months Benefit payments Defined Benefit Plan, Benefits Paid Transition obligation Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Transition Assets (Obligations), before Tax Rate of compensation increase (as a percent) Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Rate of Compensation Increase Target allocation (as a percent) Defined Benefit Plan, Target Plan Asset Allocations Change in Plan Assets Changes in fair value for assets that are measured at fair value on a recurring basis Defined Benefit Plan, Change in Fair Value of Plan Assets [Roll Forward] Net periodic benefit cost Defined Benefit Plan, Net Periodic Benefit Cost Effect of 1% increase on service and interest cost components of net periodic other postretirement benefit costs Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components Plan amendments Defined Benefit Plan, Plan Amendments Estimated Future Benefit Payments Defined Benefit Plan, Expected Future Benefit Payments, Fiscal Year Maturity [Abstract] Effect of 1% increase on the accumulated other postretirement benefit obligation Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation Service cost Service cost - benefits earned during the period Defined Benefit Plan, Service Cost Accumulated benefit obligation Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Accumulated Benefit Obligation Funded Status at the end of the period Defined Benefit Plan, Funded Status of Plan Change in Benefit Obligation Defined Benefit Plan, Change in Benefit Obligation [Roll Forward] Interest cost on benefit obligation Interest cost Defined Benefit Plan, Interest Cost Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Projected Benefit Obligation Projected benefit obligation Defined Benefit Plan, Fair Value of Plan Assets Fair value of plan assets Balance at the beginning of the period Balance at the end of the period Defined Benefit Plan, Contributions by Employer Employer's contributions under the plan Employer contributions Effects of one percentage point change in the assumed initial and ultimate health care cost trend rates Defined Benefit Plan, Effect of One-Percentage Point Change in Assumed Health Care Cost Trend Rates [Abstract] Initial healthcare cost trend rate (as a percent) Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year Net periodic benefit costs and the portion of these costs charged to expense Defined Benefit Plan, Net Periodic Benefit Cost [Abstract] Projected benefit obligation and the accumulated benefit obligation for pension plans with an accumulated obligation in excess of plan assets Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets [Abstract] Expected return on plan assets Defined Benefit Plan, Expected Return on Plan Assets Defined Benefit Plan, Estimated Future Employer Contributions in Next Fiscal Year (Deprecated 2013-01-31) Fair value of plan assets Defined Benefit Plan, Pension Plans with Accumulated Benefit Obligations in Excess of Plan Assets, Aggregate Fair Value of Plan Assets Expenses recorded for the defined contribution savings plan Defined Contribution Plan, Cost Recognized Defined Benefit Plan, Asset Categories [Axis] Defined Benefit Plan and Other Postretirement Benefit Plan [Domain] Actual asset allocation (as a percent) Defined Benefit Plan, Actual Plan Asset Allocations Actual return on assets still held Defined Benefit Plan, Actual Return on Plan Assets Still Held Weighted-average assumptions used to determine net periodic benefit costs Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract] Transfers in and/or out of Level 3 Defined Benefit Plan, Transfers Between Measurement Levels Employee Savings Plan Benefits Defined Contribution Pension and Other Postretirement Plans Disclosure [Abstract] Purchases, sales, and settlements Defined Benefit Plan, Purchases, Sales, and Settlements Defined Benefit Plans and Other Postretirement Benefit Plans [Axis] Ultimate healthcare cost trend rate (as a percent) Defined Benefit Plan, Ultimate Health Care Cost Trend Rate Prior service cost (credit) Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Prior Service Cost (Credit), before Tax Depreciation and amortization including nuclear fuel Depreciation and amortization Depreciation, Depletion and Amortization Liabilities from risk management activities (Note 7) Derivative Liability, Noncurrent Liabilities from risk management activities (Note 7) Deferred Credits and Other Amounts Offset Derivative Asset, Fair Value, Gross Liability Derivative Asset, Fair Value, Net (Deprecated 2013-01-31) Interest rate swaps liabilities Commodity contracts, liabilities Derivative Financial Instruments, Liabilities [Member] Other Derivative, Collateral, Right to Reclaim Cash Assets from risk management activities (Note 7) Current assets Assets from risk management activities (Note 7) Derivative Instruments and Hedges, Assets Derivative instruments: Derivative instruments: Derivative Instruments and Hedges, Assets [Abstract] Derivative Accounting Derivative [Line Items] Amount Reported on Balance Sheet Derivative Assets (Liabilities), at Fair Value, Net Amounts Offset Derivative Liability, Fair Value, Gross Asset Net Gain (Loss) Recognized in Income from Derivative Instruments Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net Derivative Instrument [Axis] Hedging assets Commodity contracts, assets Derivative Financial Instruments, Assets [Member] Derivative [Table] Assets from risk management activities (Note 7) Assets from risk management activities (Note 7) Derivative Instruments and Hedges, Noncurrent Derivative Accounting Risk management activities-derivative instruments: Commodity Contracts Risk management assets Risk management activities-derivative instruments: Commodity contracts Amount Reported on Balance Sheet Derivative Asset Risk management activities-derivative instruments: Commodity Contracts Derivative Liability Liabilities Amount Reported on Balance Sheet Total Liabilities Derivative Accounting Derivative Instruments and Hedging Activities Disclosure [Text Block] Other Derivative, Collateral, Obligation to Return Cash Net Recognized Derivatives Derivative Asset, Fair Value, Amount Not Offset Against Collateral Gross Recognized Derivatives Derivative Liability, Fair Value, Gross Liability Total Derivative Instruments Derivative, Fair Value, Net Total derivatives Derivative, by Nature [Axis] Gross Recognized Derivatives Derivative Asset, Fair Value, Gross Asset Net Recognized Derivatives Derivative Liability, Fair Value, Amount Not Offset Against Collateral Derivative, Name [Domain] Gains and losses from derivative instruments Derivative Instruments, Gain (Loss) [Line Items] Gains and losses from derivative instruments Derivative, Gain (Loss) on Derivative, Net [Abstract] Gain (Loss) Recognized in Income (Ineffective Portion and Amount Excluded from Effectiveness Testing) Derivative Instruments, Gain (Loss) Recognized in Income, Ineffective Portion and Amount Excluded from Effectiveness Testing, Net Aggregate Fair Value of Derivative Instruments in a Net Liability Position Derivative, Net Liability Position, Aggregate Fair Value Liabilities from risk management activities (Note 17) Current Liabilities Derivative Instruments and Hedges, Liabilities Liabilities from risk management activities (Note 7) Loss Reclassified from Accumulated OCI into Income (Effective Portion Realized) Derivative Instruments, Gain (Loss) Reclassified from Accumulated OCI into Income, Effective Portion, Net Derivative Instruments, Gain (Loss) [Table] Credit Risk and Credit-Related Contingent Features Derivative, Credit Risk Related Contingent Features [Abstract] Derivative Contract [Domain] Gain (loss) Recognized in OCI on Derivative Instruments (Effective Portion) Derivative Instruments, Gain (Loss) Recognized in Other Comprehensive Income (Loss), Effective Portion, Net Derivative Accounting Derivatives, Policy [Policy Text Block] Fair value of derivative instruments with credit risk and credit-related contingent features Derivatives, Fair Value [Line Items] Stock-Based Compensation Disclosure of Compensation Related Costs, Share-based Payments [Text Block] Stock-Based Compensation Income tax expense (benefit) on discontinued operations Less: income tax expense (benefit) on discontinued operations Discontinued Operation, Tax Effect of Discontinued Operation Income (loss) before taxes Discontinued Operation, Income (Loss) from Discontinued Operation, before Income Tax Discontinued Operations Gain on sale of district cooling business After-tax gain from discontinued operations Discontinued Operation, Gain (Loss) on Disposal of Discontinued Operation, Net of Tax Inter-company receivables Disposal Group, Including Discontinued Operation, Accounts, Notes and Loans Receivable, Net Disposal Groups, Including Discontinued Operations, Name [Domain] Revenue Disposal Group, Including Discontinued Operation, Revenue Other assets Disposal Group, Including Discontinued Operation, Other Assets Discontinued Operations Disposal Groups, Including Discontinued Operations, Disclosure [Text Block] Dividends on common stock Dividends on common stock Dividends, Common Stock Dividends, Common Stock, Cash Common stock dividends declared ($2.23, $2.67, and $ 2.10 per share) Dividends on common stock Dividends on common stock Dividends accrued but not yet paid Dividends Payable Common dividends payable Dividends Payable, Current Eligible Item or Group for Fair Value Option [Axis] Basic earnings per share: Earnings Per Share, Basic [Abstract] Diluted earnings per share: Earnings Per Share, Diluted [Abstract] Earnings Per Share: Earnings Per Share, Basic and Diluted [Abstract] Earnings Per Share Earnings Per Share [Text Block] Net income attributable to common shareholders - basic (in dollars per share) Earnings per share - basic (in dollars per share) Earnings per average common share attributable to common shareholders -basic (in dollars per share) Earnings Per Share, Basic Net income attributable to common shareholders - diluted (in dollars per share) Earnings per share - diluted (in dollars per share) Net income attributable to common shareholders - Diluted (in dollars per share) Earnings Per Share, Diluted Earnings per average common share attributable to common shareholders -diluted (in dollars per share) Earnings Per Share [Abstract] EARNINGS PER WEIGHTED-AVERAGE COMMON SHARE OUTSTANDING Earnings Per Share Federal income tax rate (as a percent) Effective Income Tax Rate Reconciliation, at Federal Statutory Income Tax Rate, Percent ELECTRIC OPERATING REVENUES Regulated electricity Electric Domestic Regulated Revenue Stock Options Employee Stock Option [Member] Total income tax benefit recognized Employee Service Share-based Compensation, Tax Benefit from Compensation Expense Tax benefit realized for the tax deductions from option exercises Employee Service Share-based Compensation, Tax Benefit Realized from Exercise of Stock Options Total unrecognized compensation cost related to nonvested share-based compensation arrangements granted Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized Expected weighted-average period of recognition of unrecognized compensation cost Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition Fossil fuel (at average cost) Energy Related Inventory, Other Fossil Fuel Environmental Remediation Site [Axis] Environmental Remediation Site [Domain] Equity-Based Arrangements, Individual Contracts, Type of Deferred Compensation [Domain] Equity Component [Domain] U.S. Equities Equity Securities Equity Securities [Member] Impact of the reclassifications to prior year (previously reported) amounts Reclassifications to prior year amounts Error Corrections and Prior Period Adjustments Restatement [Line Items] Fair Value Estimate of Fair Value Measurement [Member] Amount of debt redeemed Extinguishment of Debt, Amount Liability Class [Axis] Information regarding the entity's internally developed significant unobservable inputs used to value its level 3 instruments Fair Value Inputs, Assets, Quantitative Information [Line Items] Information regarding the entity's internally developed significant unobservable inputs used to value its level 3 instruments Fair Value Inputs, Liabilities, Quantitative Information [Line Items] Fair Value Inputs, Assets, Quantitative Information [Table] Fair value measurement on a recurring basis Fair Value, Measurements, Recurring [Member] Fair Value by Liability Class [Domain] Included in earnings Fair Value, Assets and Liabilities Measured on Recurring Basis, Gain (Loss) Included in Earnings Fair Value Inputs, Liabilities, Quantitative Information [Table] Measurement Frequency [Axis] Included in OCI Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Gain (Loss) Included in Other Comprehensive Income (Loss) Fair Value, Hierarchy [Axis] Fair Value Measurements, Recurring and Nonrecurring [Table] Asset Class [Axis] Asset Class [Domain] Fair Value, Measurement Frequency [Domain] Information regarding the entity's internally developed significant unobservable inputs used to value its level 3 instruments Fair Value Inputs, Assets, Quantitative Information [Table Text Block] Fair value of assets and liabilities that are measured at fair value on a recurring basis Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items] Fair Value Measurements Fair Value Inputs, Comparability Adjustments Comparability Adjustment Fair Value Hierarchy [Domain] Fair Value Measurements Fair Value Disclosures [Text Block] Fair Value Measurements Fair Value of Financial Instruments, Policy [Policy Text Block] Long-term debt, including current maturities Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items] Fair Value, by Balance Sheet Grouping [Table] Schedule of estimated fair value of long-term debt, including current maturities Fair Value, by Balance Sheet Grouping [Table Text Block] Significant Other Observable Inputs (Level 2) Fair Value, Inputs, Level 2 [Member] Quoted Prices in Active Markets for Identical Assets (Level 1) Fair Value, Inputs, Level 1 [Member] Significant Unobservable Inputs (Level 3) Fair Value, Inputs, Level 3 [Member] Fair Value, Option, Eligible Item or Group [Domain] Fair Values Derivatives, Balance Sheet Location, by Derivative Contract Type [Table] 2017 Finite-Lived Intangible Assets, Amortization Expense, Year Four Amortization period Weighted average remaining amortization period for intangible assets Finite-Lived Intangible Asset, Useful Life Estimated amortization expense on existing intangible assets over the next five years Finite-Lived Intangible Assets, Net, Amortization Expense, Fiscal Year Maturity [Abstract] Accumulated amortization on intangible assets Accumulated amortization on intangible assets Finite-Lived Intangible Assets, Accumulated Amortization 2014 Finite-Lived Intangible Assets, Amortization Expense, Next Twelve Months Finite-Lived Intangible Assets, Amortization Expense, Year Five 2018 Finite-Lived Intangible Assets, Amortization Expense, Year Two 2015 2016 Finite-Lived Intangible Assets, Amortization Expense, Year Three Fixed income securities. Fixed Income Securities [Member] Fossil plant Fossil Fuel Plant [Member] Asset dispositions Gain (Loss) on Disposition of Property Plant Equipment, Excluding Oil and Gas Property and Timber Property Investment gains - net Investment losses - net Gain on Sale of Investments Gains and other changes in real estate assets Gain (Loss) on Sale of Other Investments Gain on real estate debt restructuring Gains (Losses) on Restructuring of Debt Guarantees and Surety Bonds Guarantor Obligations [Line Items] Guarantees and Surety Bonds Guarantees and Surety Bonds Guarantees [Text Block] Hedging Designation [Axis] Hedging Designation [Domain] Real estate impairment charges Impairment of Real Estate Real estate impairment charges Impairment of Long-Lived Assets to be Disposed of Income from continuing operations attributable to common shareholders - Basic (in dollars per share) Income from continuing operations attributable to common shareholders - basic (in dollars per share) Income from continuing operations attributable to common shareholders (in dollars per share) Income (Loss) from Continuing Operations, Per Basic Share INCOME (LOSS) FROM DISCONTINUED OPERATIONS Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest [Abstract] Income from continuing operations, net of tax Income (Loss) from Continuing Operations Attributable to Parent Income (loss) from discontinued operations (in dollars per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Diluted Share CONDENSED CONSOLIDATED STATEMENTS OF INCOME Income Statement Location [Axis] INCOME BEFORE INCOME TAXES Income (Loss) from Continuing Operations before Income Taxes, Extraordinary Items, Noncontrolling Interest Income Taxes Disposal Group Name [Axis] Income Taxes Income Tax Contingency [Line Items] Discontinued Operations Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items] Income from continuing operations attributable to common shareholders - diluted (in dollars per share) Income from continuing operations attributable to common shareholders (in dollars per share) Income from continuing operations attributable to common shareholders - Diluted (in dollars per share) Income (Loss) from Continuing Operations, Per Diluted Share Net of income tax expense (benefit) of $--, $(3,813) and $7,418 (Note 1) Income (Loss) from Discontinued Operations, Net of Tax, Including Portion Attributable to Noncontrolling Interest Income (loss) from discontinued operations - net of income taxes Income Statement Location [Domain] Income (loss) from discontinued operations (in dollars per share) Income (Loss) from Discontinued Operations and Disposal of Discontinued Operations, Net of Tax, Per Basic Share Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Table] Income Tax Contingency [Table] Anticipated refund reduction amount Income Tax Examination, Liability (Refund) Adjustment from Settlement with Taxing Authority INCOME TAXES Income Taxes Income tax expense - continuing operations Income tax benefit Income Taxes Income Tax Expense (Benefit) Income Taxes Income Tax Disclosure [Text Block] Medicare Subsidy Part-D Effective Income Tax Rate Reconciliation, Deduction, Medicare Prescription Drug Benefit, Amount Comparison of pretax income from continuing operations at the federal income tax rate to income tax expense - continuing operations Effective Income Tax Rate Reconciliation, Amount [Abstract] Income from continuing operations INCOME FROM CONTINUING OPERATIONS Income (Loss) from Continuing Operations, Including Portion Attributable to Noncontrolling Interest Income taxes, net of refunds Income Taxes Paid, Net Income Tax Receivables Income Taxes Receivable, Current Income tax receivable (Note 5) Income tax receivable (Note 5) Income (loss) after taxes Income (Loss) from Discontinued Operations, Net of Tax, Attributable to Parent Discontinued operations, net of tax Federal income tax expense at 35% statutory rate Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount State income tax net of federal income tax benefit Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount Other Effective Income Tax Rate Reconciliation, Other Adjustments, Amount Palo Verde VIE noncontrolling interest Effective Income Tax Rate Reconciliation, Noncontrolling Interest Income (Loss), Amount Income Taxes Income Tax, Policy [Policy Text Block] Long-term income tax receivables Income Taxes Receivable, Noncurrent Income tax receivable (Note 5) Income tax receivable (Notes 5) Change in margin and collateral accounts - assets Increase (Decrease) in Deposit Assets Decrease to the liability for asset retirements Increase (Decrease) in Asset Retirement Obligations Accrued taxes and income tax receivable - net Increase (Decrease) in Income Taxes Payable Accrued taxes Accrued taxes and income taxes receivable - net Increase (Decrease) in Accrued Taxes Payable Accounts payable Increase (Decrease) in Accounts Payable Decrease in long term deferred tax liability Increase (Decrease) in Deferred Income Taxes Increase in deferred income tax liabilities Decrease in income taxes Increase (Decrease) in Income Taxes Other current liabilities Increase (Decrease) in Other Accrued Liabilities Change in other long-term liabilities Increase (Decrease) in Other Operating Liabilities Changes in current assets and liabilities: Increase (Decrease) in Operating Capital [Abstract] Materials, supplies and fossil fuel Increase (Decrease) in Inventories Income tax receivable - net Income tax receivable Increase (Decrease) in Income Taxes Receivable Change in other long-term assets Increase (Decrease) in Other Operating Assets Customer and other receivables Increase (Decrease) in Receivables Accounts receivable Other current assets Increase (Decrease) in Prepaid Expense Deferred fuel and purchased power Deferred fuel and purchased power costs-current period Increase (Decrease) in Regulatory Clause Revenue Change in regulatory assets Increase (Decrease) in Regulatory Assets and Liabilities Change in other regulatory liabilities Change in long-term regulatory liabilities Change in regulatory liabilities Increase (Decrease) in Regulatory Liabilities Accrued unbilled revenues Increase (Decrease) in Unbilled Receivables Changes in equity Increase (Decrease) in Shareholders' Equity Increase (Decrease) in Stockholders' Equity [Roll Forward] Dilutive stock options and performance shares Incremental Common Shares Attributable to Dilutive Effect of Share-based Payment Arrangements Intangible assets, net of accumulated amortization Intangible Assets, Net (Excluding Goodwill) Intangible assets, net of accumulated amortization Intangible Assets Intangible Assets, Finite-Lived, Policy [Policy Text Block] Accrued interest Interest Payable, Current INTEREST EXPENSE Interest Expense Interest Expense [Abstract] Interest charges Interest expense Interest Costs Incurred Total Interest Expense Interest on short-term borrowings Interest Expense, Short-term Borrowings Interest on long-term debt Interest Expense, Long-term Debt Interest, net of amounts capitalized Interest Paid, Net Materials and Supplies Inventory, Policy [Policy Text Block] Interest income Investment Income, Interest Income taxes - investment tax credit basis adjustment Income taxes-deferred investment tax credit Investment Tax Credit Carryforward [Member] Investments Investment, Policy [Policy Text Block] Deferred investment tax credit Investment Tax Credit Deferred investment tax credit Fair value of fixed income securities, summarized by contractual maturities Investments Classified by Contractual Maturity Date [Table Text Block] Nuclear Decommissioning Trusts Investments Investments [Abstract] Nuclear Decommissioning Trusts Investments in Debt and Marketable Equity Securities (and Certain Trading Assets) Disclosure [Text Block] Interests in jointly-owned facilities Jointly Owned Utility Plant Interests [Line Items] Percent Owned Jointly Owned Utility Plant, Proportionate Ownership Share Jointly-Owned Facilities Jointly Owned Utility Plant [Axis] Construction Work in Progress Jointly Owned Utility Plant, Ownership Amount of Construction Work in Progress Accumulated Depreciation Jointly Owned Utility Plant, Ownership Amount of Plant Accumulated Depreciation Jointly Owned Utility Plant Interests [Table] Jointly Owned Utility Plant [Domain] Plant in Service Jointly Owned Utility Plant, Gross Ownership Amount of Plant in Service Outstanding letters of credit Letters of Credit Used Letters of Credit Outstanding, Amount Weighted-average interest rate (as a percent) Long-term Debt, Weighted Average Interest Rate Lease expense Operating Leases, Rent Expense Leases Leases Leases of Lessee Disclosure [Text Block] Letters of credit Letter of Credit [Member] Variable interest rate pollution control bonds Total current liabilities Liabilities, Current TOTAL LIABILITIES AND EQUITY Liabilities and Equity Total Liabilities Liabilities, Total [Member] Liabilities assumed relating to acquisition of SCE Four Corners' interest (see Note 3) Liabilities Assumed Liabilities assumed related to acquisition of SCE's Four Corners' interest Liabilities Financial and Nonfinancial Liabilities, Fair Value Disclosure CURRENT LIABILITIES Current liabilities Liabilities, Current [Abstract] Liabilities held for sale Disposal Group, Including Discontinued Operation, Liabilities LIABILITIES AND EQUITY Liabilities and Equity Liabilities and Equity [Abstract] Liabilities Liabilities, Fair Value Disclosure [Abstract] Unrecognized tax benefits (Note 5) Liability for Uncertain Tax Positions, Noncurrent Commitment Fees (as a percent) Line of Credit Facility, Unused Capacity, Commitment Fee Percentage Outstanding borrowings Long-term Line of Credit Maximum borrowing capacity on credit facility upon satisfaction of certain conditions and consent of lenders Line of Credit Facility, Maximum Borrowing Capacity Long term debt Line of Credit [Member] Amount Committed Current borrowing capacity on credit facility Line of Credit Facility, Current Borrowing Capacity Unused Amount Line of Credit Facility, Remaining Borrowing Capacity Litigation Case [Domain] Litigation Case [Axis] Amount of civil penalty agreed in settlement Litigation Settlement, Amount LONG-TERM DEBT LESS CURRENT MATURITIES (Note 6) Long-term Debt, Unclassified [Abstract] Carrying Amount Long-term debt Long-term Debt Fair Value Carrying Amount Long-term Debt, Fair Value Long-term debt less current maturities (Note 2) Long-term debt less current maturities Long-term Debt and Capital Lease Obligations Long-Term Debt and Liquidity Matters Long-term Debt [Text Block] Commercial paper borrowings outstanding Long-term Commercial Paper, Current 2011 Long-term Debt, Maturities, Repayments of Principal, Remainder of Fiscal Year 2014 Long-term Debt, Maturities, Repayments of Principal in Next Twelve Months 2016 Long-term Debt, Maturities, Repayments of Principal in Year Three 2015 Long-term Debt, Maturities, Repayments of Principal in Year Two Less current maturities Long-term Debt and Capital Lease Obligations, Current Principal payments due on long-term debt Long-term Debt, Fiscal Year Maturity [Abstract] Total long-term debt less current maturities Long-term debt less current maturities Long-term Debt, Excluding Current Maturities LONG-TERM DEBT LESS CURRENT MATURITIES (Note 2) 2017 Long-term Debt, Maturities, Repayments of Principal in Year Four Thereafter Long-term Debt, Maturities, Repayments of Principal after Year Five 2018 Long-term Debt, Maturities, Repayments of Principal in Year Five Number of defendants against whom Roosevelt Irrigation District ("RID") filed lawsuit Loss Contingency, Number of Defendants Investment losses - net Loss on Sale of Investments Loss Contingency Nature [Axis] Loss Contingency, Nature [Domain] Loss on reacquired debt Loss on Reacquired Debt [Member] Major Types of Debt and Equity Securities [Axis] Major Types of Debt and Equity Securities [Domain] Margin account Margin Deposit Assets Discounted Market Prices Discounted cash flows Market Approach Valuation Technique [Member] Maximum Maximum [Member] Coal mine reclamation Mine Reclamation and Closing Liability, Noncurrent Minimum Minimum [Member] Net capital activities by noncontrolling interests Noncontrolling Interest, Decrease from Distributions to Noncontrolling Interest Holders Noncontrolling interests (Note 6) Equity - Noncontrolling interests Noncontrolling interests (Note 6) Stockholders' Equity Attributable to Noncontrolling Interest Mortgage-backed securities Collateralized Mortgage Backed Securities [Member] Changes in reserve for uncollectibles Movement in Valuation Allowances and Reserves [Roll Forward] Commodity - Gas Natural Gas [Member] CASH FLOWS FROM FINANCING ACTIVITIES Cash flows from financing activities Net Cash Provided by (Used in) Financing Activities [Abstract] Net income attributable to common shareholders NET INCOME ATTRIBUTABLE TO COMMON SHAREHOLDERS Net income (loss) attributable to common shareholder Net Income (Loss) Available to Common Stockholders, Basic Net income attributable to common shareholder AMOUNTS ATTRIBUTABLE TO COMMON SHAREHOLDERS: Net Income (Loss) Available to Common Stockholders, Basic [Abstract] CASH FLOWS FROM INVESTING ACTIVITIES Cash flows from investing activities Net Cash Provided by (Used in) Investing Activities [Abstract] Net cash flow used for investing activities Net Cash Provided by (Used in) Investing Activities CASH FLOWS FROM OPERATING ACTIVITIES Cash Flows from Operating Activities Cash flows from operating activities Net Cash Provided by (Used in) Operating Activities [Abstract] Net cash flow used for financing activities Net Cash Provided by (Used in) Financing Activities Net cash flow provided by operating activities Net Cash Provided by (Used in) Operating Activities Increase in net income due to consolidation of Palo Verde Sale Leaseback Trusts Less: Net income attributable to noncontrolling interests (Note 6) Less: Comprehensive income attributable to noncontrolling interests Net Income (Loss) Attributable to Noncontrolling Interest Net income attributable to noncontrolling interests Net income attributable to noncontrolling interests New Accounting Standards New Accounting Standards New Accounting Pronouncements and Changes in Accounting Principles [Text Block] Total Nonoperating Income (Expense) OTHER INCOME (DEDUCTIONS) Other Nonoperating Income (Expense) [Abstract] Outstanding gross notional amount of derivatives Notional Disclosures [Abstract] Nuclear fuel, net of accumulated amortization Nuclear Fuel, Net of Amortization Nuclear fuel, net of accumulated amortization Nuclear plant Nuclear Plant [Member] NONCONTROLLING INTERESTS Noncontrolling Interests Noncontrolling Interest [Member] NONCONTROLLING INTEREST Noncontrolling Interest [Abstract] Not Designated as Hedging Instruments Not Designated as Hedging Instrument [Member] Liabilities Offsetting Derivative Liabilities [Abstract] Assets Offsetting Derivative Assets [Abstract] 2018 Operating Leases, Future Minimum Payments, Due in Five Years Estimated future minimum lease payments for operating leases, excluding purchased power agreements Operating Leases, Future Minimum Payments Due, Fiscal Year Maturity [Abstract] 2017 Operating Leases, Future Minimum Payments, Due in Four Years 2016 Operating Leases, Future Minimum Payments, Due in Three Years 2015 Operating Leases, Future Minimum Payments, Due in Two Years OPERATING INCOME Operating income Operating loss Operating Income (Loss) Thereafter Operating Leases, Future Minimum Payments, Due Thereafter 2014 Operating Leases, Future Minimum Payments Due, Next Twelve Months Leases Operating Leased Assets [Line Items] Total future lease commitments Operating Leases, Future Minimum Payments Due Consolidation and Nature of Operations Consolidation and Nature of Operations Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block] Prior service cost, tax benefit Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), Tax Tax benefit Amortization of actuarial loss, net of tax benefit Actuarial loss, net of tax benefit of $1,950, $1,870 and $1,705 Actuarial loss, net of tax benefit of $1,724, $1,658 and $1,387 Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Net of Tax Other Comprehensive Income (Loss), Net of Tax Total other comprehensive income Other comprehensive income (loss) attributable to common shareholders Other comprehensive income Other comprehensive income attributable to common shareholders Reclassification of net realized loss, tax benefit Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), Tax Tax benefit Actuarial loss, net of tax benefit Net unrealized gains (losses) related to pension benefits Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, before Tax Net unrealized gains (losses) related to pension and other postretirement benefits Pension and other postretirement benefits activity, tax expense Pension and other postretirement benefits activity, tax benefit Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Tax Pension and other postretirement benefits activity, tax benefit (expense) Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, before Tax Net reclassification of realized losses to income Prior service cost, net of tax benefit of $194, $193 and $190 Prior service cost, net of tax benefit of $179, $201 and $215 Other Comprehensive (Income) Loss, Amortization Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Prior Service Cost (Credit), Net of Tax Amortization of prior service cost, net of tax benefit Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Net of Tax Net realized loss, net of tax benefit Reclassification of net realized loss, net of tax benefit of $1,261 and $2,824 for three months ended June 30, 2014 and 2013 and $2,584 and $6,124 for six months ended June 30, 2014 and 2013 Reclassification of net realized loss, net of tax benefit of $1,261 and $2,824 for three months ended June 30, 2014 and 2013 and of $2,584 and $6,124 for six months ended June 30, 2014 and 2013 OCI (loss) before reclassifications Other Comprehensive Income (Loss), before Reclassifications, Net of Tax Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Gain (Loss), before Tax Reclassification of pension and other postretirement benefits to income Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Tax (Deprecated 2013-01-31) Transition obligation, tax benefit Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI, Pension and Other Postretirement Benefit Plans, for Net Transition Asset (Obligation), Tax Other Other Regulatory Assets (Liabilities) [Member] Other Comprehensive Income (Loss), Tax, Portion Attributable to Parent Tax benefit Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax Pension and other postretirement benefits activity, net of tax benefit (expense) of $845 and $449 for three months ended June 30, 2014 and 2013 and $128 and $(182) for six months ended June 30, 2014 and 2013 Pension and other postretirement benefits activity, net of tax benefit (expense) of $828 and $399 for three months ended June 30, 2014 and 2013 and of $222 and $(177) for six months ended June 30, 2014 and 2013 Other assets Other Assets, Noncurrent Other Income and Other Expense Current Assets - Other current assets Other Assets, Current Other current assets Other Other Operating Activities, Cash Flow Statement Other Comprehensive Income (Loss), Net of Tax [Abstract] OTHER COMPREHENSIVE INCOME, NET OF TAX OTHER COMPREHENSIVE INCOME, NET OF TAX Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax Unrealized actuarial loss, net of tax benefit of $(6,067), $(7,738) and $(4,223) Unrealized actuarial loss, net of tax benefit of $(3,828), $(6,344) and $(2,938) Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Tax Unrealized actuarial loss, net of tax benefit Other Other Deferred Costs, Net Other expenses Other Cost and Expense, Operating Other Debt Obligations [Member] Other Other Expense, Nonoperating [Abstract] Other expense: Other Income and Other Expense Other Income and Other Expense Disclosure [Text Block] Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Net of Tax Net unrealized gain (loss), net of tax benefit (expense) of $(26) and $105 for three months ended June 30, 2014 and 2013 and of $(624) and $67 for six months ended June 30, 2014 and 2013 Net unrealized gain (loss), net of tax benefit (expense) of $(26) and $105 for three months ended June 30, 2014 and 2013 and of $(624) and $67 for six months ended June 30, 2014 and 2013 Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, before Tax Net unrealized losses on derivative instruments Other income: Other Income, Nonoperating [Abstract] Net unrealized gain (loss), tax benefit (expense) Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax Net unrealized gain (loss), tax benefit (expense) Materials and supplies (at average cost) Other Inventory, Supplies, Gross Other expense (Note 10) Total other expense Other expense (Note S-2) Other expense Other Nonoperating Expense Other income (Note 10) Other Nonoperating Income Total other income Other income (Note S-2) Other income Other expense Other Nonoperating Income (Expense) Other Deferred credits - other Other Liabilities, Noncurrent Other current liabilities Other Liabilities, Current Current maturities of long-term debt (Note 2) Current maturities of long-term debt Less current maturities Other Long-term Debt, Current Current maturities of long-term debt Other: Other Plant in Service [Member] Net payables for securities purchases Other Payables to Broker-Dealers and Clearing Organizations Other Benefits Other Postretirement Benefit Plan [Member] Investments and Other Assets Other Investments [Member] Current Assets Other Assets [Member] Current Liabilities Other Liabilities [Member] Pinnacle West Parent Company [Member] Shareholder equity Common Shareholders Parent [Member] Other Payments for (Proceeds from) Other Investing Activities Capital expenditures Capital expenditures Payments to Acquire Productive Assets Expenditures for real estate investments Payments to Acquire Real Estate Dividends paid on common stock Payments of Ordinary Dividends, Common Stock Investment in nuclear decommissioning trust Payments to Acquire Investments to be Held in Decommissioning Trust Fund Noncontrolling interests Distributions to noncontrolling interests Payments to Noncontrolling Interests Retirement Plans and Other Benefits Pension and Other Postretirement Plans, Policy [Policy Text Block] Retirement Plans and Other Benefits Pension and Other Postretirement Benefits Disclosure [Text Block] Current liability Pension and Other Postretirement Defined Benefit Plans, Current Liabilities Portion of cost charged to expense Pension Expense Liabilities for pension and other postretirement benefits (Note 4) Liabilities for pension and other postretirement benefits (Note 4) Noncurrent liability Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent Portion of cost charged to expense Pension and Other Postretirement Benefit Expense Pension and other postretirement benefits (Note 8): Pension and Other Postretirement Benefit Expense [Abstract] Pension Benefits Pension Plan [Member] Plan Asset Categories [Domain] Par value (in dollars per share) Preferred Stock, Par or Stated Value Per Share Serial preferred stock authorized Preferred Stock, Shares Authorized Preferred stock outstanding Preferred Stock, Shares Outstanding Serial preferred stock Preferred Stock [Member] Reclassifications to prior year (previously reported) amounts Prior Period Adjustment [Abstract] Contributions in aid of construction Proceeds from Contribution in Aid of Construction Other Proceeds from (Payments for) Other Financing Activities Proceeds from nuclear decommissioning trust sales Proceeds from the sale of securities Proceeds from Decommissioning Trust Fund Assets Short-term borrowings and payments - net Short-term borrowings - net Proceeds from (Repayments of) Short-term Debt Equity infusions into APS Equity infusion Proceeds from Contributions from Parent Sale of investment Proceeds from Divestiture of Interest in Consolidated Subsidiaries Proceeds from sale of district cooling business Proceeds from Divestiture of Businesses and Interests in Affiliates Issuance of long-term debt Proceeds from Issuance of Long-term Debt Net proceeds from issuance of common stock Proceeds from Issuance Initial Public Offering Proceeds from Income Tax Refunds Income tax refunds Proceeds from sale of life insurance policies Proceeds from Life Insurance Policies Common stock equity issuance Proceeds from Issuance of Common Stock Cash received from options exercised Proceeds from Stock Options Exercised Proceeds from sale of life insurance policies Proceeds from Sale of Insurance Investments Proceeds from sale of commercial real estate investments Proceeds from Sale of Real Estate Held-for-investment NET INCOME Net income NET INCOME Net Income (Loss), Including Portion Attributable to Noncontrolling Interest Net income Net income Property, Plant and Equipment Property, Plant and Equipment, Policy [Policy Text Block] Average useful life Property, Plant and Equipment, Useful Life PROPERTY, PLANT AND EQUIPMENT (Notes 1, 6, and 10) PROPERTY, PLANT AND EQUIPMENT Property, Plant and Equipment, Net [Abstract] PROPERTY, PLANT AND EQUIPMENT Plant in service and held for future use Property, Plant and Equipment, Gross Net Property, Plant and Equipment, Net Decrease to electric plant in service Property, Plant and Equipment, Gross, Period Increase (Decrease) Property, Plant and Equipment, Type [Domain] Property, Plant and Equipment, Type [Axis] Net retail rate increase Public Utilities, Requested Rate Increase (Decrease), Amount Allowance for borrowed funds used during construction Allowance for borrowed funds used during construction Allowance for Funds Used During Construction, Capitalized Interest Total property, plant and equipment Public Utilities, Property, Plant and Equipment, Net Composite rate used to calculate AFUDC (as a percent) Public Utilities, Allowance for Funds Used During Construction, Rate Coal take-or-pay commitments Public Utilities, Inventory, Fuel [Member] Allowance for equity funds used during construction Allowance for equity funds used during construction Public Utilities, Allowance for Funds Used During Construction, Capitalized Cost of Equity Allowance for equity funds used during construction Approximate remaining average useful lives of utility property Public Utilities, Property, Plant and Equipment [Abstract] Public Utilities, Regulatory Proceeding [Axis] Public Utilities, Regulatory Proceeding [Domain] Settlement Agreement Public Utilities, Rate Matters, Approved [Abstract] Depreciation rates (as a percent) Public Utilities, Property, Plant and Equipment, Disclosure of Composite Depreciation Rate for Plants in Service Percentage of common equity in capital structure Public Utilities, Approved Equity Capital Structure, Percentage Allowance for Funds Used During Construction Public Utilities, Allowance for Funds Used During Construction, Net Increase [Abstract] Net change in base rates Public Utilities, Approved Rate Increase (Decrease), Amount Authorized return on common equity (as a percent) Public Utilities, Approved Return on Equity, Percentage Percentage of debt in capital structure Public Utilities, Approved Debt Capital Structure, Percentage Public Utility, Property, Plant and Equipment [Table] Utility Plant and Depreciation Public Utility, Property, Plant and Equipment [Line Items] Public Utility [Axis] Selected Quarterly Financial Data (Unaudited) Quarterly Financial Information [Text Block] Selected Quarterly Financial Data (Unaudited) Renewable energy standard Renewable Energy Program [Member] Removal costs Removal Costs [Member] Range [Axis] Range [Domain] Real estate Real Estate Investment [Member] Real Estate Impairment Charge Real Estate Investments Real Estate Held for Development and Sale, Policy [Policy Text Block] Allowance for Doubtful Accounts Receivables, Trade and Other Accounts Receivable, Allowance for Doubtful Accounts, Policy [Policy Text Block] Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax [Abstract] Amounts reclassified from accumulated other comprehensive loss Reclassification from Accumulated Other Comprehensive Income, Current Period, Net of Tax Amounts reclassified from accumulated other comprehensive loss Tabular reconciliation of the total amounts of unrecognized tax benefits, excluding interest and penalties, at the beginning and end of the year Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward] Regulatory Matters Regulated electricity segment Regulated Operation [Member] Regulatory Agency [Domain] Regulatory liabilities (Note 3) Regulatory Liability, Current Regulatory liabilities (Note 3) Demand side management Regulatory Clause Revenues, under-recovered [Member] Regulatory Asset [Domain] Regulatory Assets, Current Other regulatory assets (Note 3) Regulatory assets, non-current Regulatory Assets, Noncurrent Regulatory assets (Notes 3) Regulatory assets (Note 3) Regulatory Asset [Axis] Regulatory liabilities, non-current Regulatory liabilities (Note 3) Regulatory Liability, Noncurrent Regulatory liabilities (Note 3) Regulatory Agency [Axis] Detail of regulatory assets Regulatory Assets [Line Items] Regulatory Liability [Domain] Detail of regulatory liabilities Regulatory Liabilities [Line Items] Regulatory Liability [Axis] Regulatory liability of amounts recovered in retail rates in excess of amounts spent for on-site interim spent fuel storage Regulatory Liabilities Decrease in size of the credit facility Repayments of Lines of Credit Repayment of long-term debt Repayments of Long-term Debt Repayment of long-term debt Changes to conform to current year presentation Reclassifications Restatement Adjustment [Member] Restricted stock unit awards Restricted Stock Units (RSUs) [Member] Retained earnings Retained Earnings (Accumulated Deficit) RETAINED EARNINGS Retained Earnings [Member] Electric Revenues Revenue Recognition, Sales of Services [Policy Text Block] Operating Revenues Revenues [Abstract] Exercisable at the end of the period Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Intrinsic Value Exercisable at the end of the period Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Remaining Contractual Term Outstanding at the end of the period Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Remaining Contractual Term Annual lease payments Sale Leaseback Transaction, Annual Rental Payments Accumulated depreciation of Palo Verde sale leaseback Accumulated depreciation of Palo Verde sale leaseback Sale Leaseback Transaction, Accumulated Depreciation Operating revenues OPERATING REVENUES Revenue, Net Sales [Member] Revenue As previously reported Scenario, Previously Reported [Member] Scenario, Actual [Member] Amount reported after reclassifications to conform to current year presentation Scenario, Forecast [Member] Expected contributions Scenario, Unspecified [Domain] Schedule of Regulatory Liabilities [Table] Schedule of Available-for-sale Securities [Table] Fair value of assets and liabilities that are measured at fair value on a recurring basis Schedule of Fair Value, Assets and Liabilities Measured on Recurring Basis [Table Text Block] Schedule of Change in Asset Retirement Obligation [Table Text Block] Change in asset retirement obligations Schedule of Capitalization, Equity [Table] Common stock and treasury stock activity Schedule of Capitalization, Equity [Line Items] Summary of stock option activity under prior equity incentive plans Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block] Schedule of net periodic benefit costs and the portion of these costs charged to expense (including administrative costs and excluding amounts capitalized as overhead construction, billed to electric plant participants or charged or amortized to the regulatory asset) Schedule of Net Benefit Costs [Table Text Block] Detail of other income and other expense Schedule of Other Nonoperating Income (Expense) [Table Text Block] Summary of the status of performance shares and changes during the year Schedule of Nonvested Performance-based Units Activity [Table Text Block] Realized gains and losses and proceeds from the sale of securities by the nuclear decommissioning trust funds Schedule of Realized Gain (Loss) [Table Text Block] Schedule of changes in the benefit obligations and funded status Schedule of Net Funded Status [Table Text Block] Schedule of changes in shareholders' equity and changes in equity of noncontrolling interests Schedule of Stockholders Equity [Table Text Block] Schedule of changes in shareholder equity and changes in equity of noncontrolling interests Schedule of accumulated other comprehensive loss Schedule of Net Periodic Benefit Cost Not yet Recognized [Table Text Block] Summary of supplemental cash flow information Schedule of Cash Flow, Supplemental Disclosures [Table Text Block] Schedule of fair value of pension plan and other postretirement benefit plan assets, by asset category Schedule of Allocation of Plan Assets [Table Text Block] Components of income tax expense Schedule of Components of Income Tax Expense (Benefit) [Table Text Block] Schedule of changes in fair value for assets that are measured at fair value on a recurring basis using significant unobservable inputs (Level 3) Schedule of Effect of Significant Unobservable Inputs, Changes in Plan Assets [Table Text Block] Principal payments due on Pinnacle West's and APS's total long-term debt Schedule of Maturities of Long-term Debt [Table Text Block] Comparison of pretax income from continuing operations at the federal income tax rate to income tax expense - continuing operations Schedule of Effective Income Tax Rate Reconciliation [Table Text Block] Components of the net deferred income tax liability Schedule of Deferred Tax Assets and Liabilities [Table Text Block] Outstanding gross notional amount of derivatives, which represents both purchases and sales (does not reflect net position) Schedule of Notional Amounts of Outstanding Derivative Positions [Table Text Block] Summary of granted restricted stock units and stock grants and the weighted average fair value Schedule of Nonvested Restricted Stock Units Activity [Table Text Block] Schedule of estimated amounts that will be amortized from accumulated other comprehensive loss and regulatory assets into net periodic benefit cost Schedule of Amounts in Accumulated Other Comprehensive Income (Loss) to be Recognized over Next Fiscal Year [Table Text Block] Schedule of Other Derivatives Not Designated as Hedging Instruments, Statements of Financial Performance and Financial Position, Location [Table Text Block] Gains and losses from derivative instruments not designated as accounting hedges instruments Schedule of amounts recognized on the Consolidated Balance Sheets Schedule of Amounts Recognized in Balance Sheet [Table Text Block] Schedule of Future Minimum Rental Payments for Operating Leases [Table Text Block] Estimated future minimum lease payments for Pinnacle West's and APS's operating leases, excluding purchased power agreements Schedule of quarterly financial information Schedule of Quarterly Financial Information [Table Text Block] Schedule of Accumulated Other Comprehensive Income (Loss) [Table Text Block] Schedule of changes in accumulated other comprehensive loss including reclassification adjustments, net of tax, by component Schedule of Regulatory Assets [Table] Schedule of projected benefit obligation and the accumulated benefit obligation for pension plans with an accumulated obligation in excess of plan assets Schedule of Benefit Obligations in Excess of Fair Value of Plan Assets [Table Text Block] Schedule of Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates [Table Text Block] Schedule of effects of one percentage point change in the assumed initial and ultimate health care cost trend rates Schedule of earnings per weighted average common share outstanding Schedule of Earnings Per Share, Basic and Diluted [Table Text Block] Nuclear decommissioning trust fund assets Schedule of Available-for-sale Securities [Line Items] Schedule of weighted-average assumptions used for both the pension and other benefits to determine benefit obligations and net periodic benefit costs Schedule of Assumptions Used [Table Text Block] Schedule of Business Acquisitions, by Acquisition [Table] Schedule of Operating Leased Assets [Table] Schedule of estimated future benefit payments, which reflect estimated future employee service, for the next five years and the succeeding five years thereafter Schedule of Expected Benefit Payments [Table Text Block] Components of long-term debt on the Consolidated Balance Sheets Schedule of Long-term Debt Instruments [Table Text Block] Schedule of Disposal Groups, Including Discontinued Operations, Income Statement, Balance Sheet and Additional Disclosures [Table Text Block] Revenue, income (loss) before income taxes and income (loss) after taxes from discontinued operations Condensed Financial Statements [Table] Schedule of Error Corrections and Prior Period Adjustment Restatement [Table] Schedule of Defined Benefit Plans Disclosures [Table] Schedule of consolidated credit facilities and amounts available and outstanding Schedule of Line of Credit Facilities [Table Text Block] Amounts and approximate terms of guarantees and surety bonds Schedule of Guarantor Obligations [Table Text Block] Schedule of previously reported amounts Schedule of Error Corrections and Prior Period Adjustments [Table Text Block] Schedule of Guarantor Obligations [Table] Schedule of Jointly Owned Utility Plants [Table Text Block] APS's interests in jointly-owned facilities recorded on the Consolidated Balance Sheets Financial data by business segment Schedule of Segment Reporting Information, by Segment [Table Text Block] Schedule of Segment Reporting Information, by Segment [Table] Fair value of derivative instruments, margin account and cash collateral reported on a gross basis Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block] SCHEDULE II - RESERVE FOR UNCOLLECTIBLES Schedule of Valuation and Qualifying Accounts Disclosure [Text Block] Schedule of regulatory assets Schedule of Regulatory Assets [Table Text Block] Amounts relating to the VIEs included in Condensed Consolidated Balance Sheets Schedule of Variable Interest Entities [Table Text Block] Schedule of regulatory liabilities Schedule of Regulatory Liabilities [Table Text Block] Schedule of Share-based Compensation Arrangements by Share-based Payment Award [Table] Schedule of Variable Interest Entities [Table] Gains and losses from derivative instruments in designated cash flow accounting hedges relationships Derivative Instruments, Gain (Loss) [Table Text Block] Term loan facility Secured Debt [Member] Business Segments Financial data by business segment Segment Reporting Information, Additional Information [Abstract] Business Segments Segment Reporting Information [Line Items] Business Segments Segment Reporting, Policy [Policy Text Block] Segments [Domain] Business Segments Segment Reporting Disclosure [Text Block] Term Loan Senior Notes [Member] Preferred stock series 1 Series A Preferred Stock [Member] Preferred stock series 3 Series C Preferred Stock [Member] Preferred stock series 2 Series B Preferred Stock [Member] Additional disclosures Share-based Compensation Arrangement by Share-based Payment Award, Additional General Disclosures [Abstract] Performance period Share-based Compensation Arrangement by Share-based Payment Award, Award Requisite Service Period Additional disclosures Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract] Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number of Shares [Roll Forward] Nonvested shares Granted (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period Granted (in dollars per share) Grant date fair value (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value Balance at the end of the period (in shares) Balance at the beginning of the period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number Vested (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period Vesting period Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value [Abstract] Weighted-Average Grant-Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award [Line Items] Stock-Based Compensation Balance at the end of the period (in dollars per share) Balance at the beginning of the period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value Forfeited (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value Forfeited (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period Share-based Compensation Arrangements by Share-based Payment Award, Options, Exercises in Period, Weighted Average Exercise Price Exercised (in dollars per share) Exercisable at the end of the period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Weighted Average Exercise Price Total fair value of shares vested Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Fair Value Vested (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercisable, Number Exercisable at the end of the period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Intrinsic Value Intrinsic value of options exercised Common shares to be available for grant under the 2012 Long Term Incentive Plan Share-based Compensation Arrangement by Share-based Payment Award, Number of Shares Authorized Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price Forfeited or expired (in dollars per share) Forfeited or expired (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Forfeitures and Expirations in Period Outstanding at the beginning of the period (in dollars per share) Outstanding at the end of the period (in dollars per share) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price Outstanding at the end of the period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number Outstanding at the beginning of the period (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Shares Issued in Period Number of shares issued for stock grant Outstanding at the end of the period Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Intrinsic Value Stock option activity under prior equity incentive plans Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward] Equity Award [Domain] Offering price of common stock issued (in dollars per share) Shares Issued, Price Per Share Short-term Investments [Member] Short-term investments Short-term borrowings Short-term borrowings (Note 2) Short-term Debt Lines of Credit and Short-Term Borrowings Short-term Debt [Text Block] Weighted Average Interest Rate (as a percent) Short-term Debt, Weighted Average Interest Rate Lines of Credit and Short-Term Borrowings Short-term Debt [Line Items] Decrease in uncertain tax positions lower bound Significant (Increase) Decrease in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Lower Bound Decrease in uncertain tax positions upper bound Significant (Increase) Decrease in Unrecognized Tax Benefits is Reasonably Possible, Estimated Range of Change, Upper Bound Summary of Significant Accounting Policies Significant Accounting Policies [Text Block] Expected environmental cost Site Contingency, Loss Exposure Not Accrued, Best Estimate Site Contingency [Table] Environmental Matters Site Contingency [Line Items] Scenario [Axis] Statement [Table] Statement Shareholder equity and equity of noncontrolling interests Common stock and treasury stock activity Other Income and Other Expense SCHEDULE II - RESERVE FOR UNCOLLECTIBLES Statement [Line Items] CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS Equity Components [Axis] CONDENSED CONSOLIDATED BALANCE SHEETS Segments [Axis] Reissuance of treasury stock for stock compensation (in shares) Stock Issued During Period, Shares, Treasury Stock Reissued Exercised (in shares) Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period Reissuance (purchase) of treasury stock - net Stock Issued During Period, Value, Treasury Stock Reissued Reissuance of treasury stock used for stock compensation Common stock issuance (in shares) Common stock issued (in shares) Stock Issued During Period, Shares, New Issues Issuance of capital stock Stock Issued During Period, Value, New Issues Common stock issuance EQUITY (Note 8) CAPITALIZATION Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract] Other (primarily stock compensation) Other Other Stockholders' Equity, Other Stockholders' Equity, Period Increase (Decrease) Total shareholders' equity Total shareholder equity Stockholders' Equity Attributable to Parent Other (in shares) Stockholders' Equity, Other Shares Total equity Balance Balance Total shareholder equity Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest Changes in Equity Common Stock and Treasury Stock Changes in Equity Stockholders' Equity Note Disclosure [Text Block] Net Metering Application Subsequent Event [Member] Subsequent event Subsequent Event Type [Domain] Subsequent Event Type [Axis] ARIZONA PUBLIC SERVICE COMPANY. Subsidiaries [Member] Tabular reconciliation of the total amounts of unrecognized tax benefits, excluding interest and penalties, at the beginning and end of the year Summary of Income Tax Contingencies [Table Text Block] Supplemental disclosure of cash flow information Supplemental disclosure of cash flow information: Supplemental Cash Flow Information [Abstract] Accrued taxes (Note 5) Taxes Payable, Current Accrued taxes (Note 5) Taxes other than income taxes Taxes, Miscellaneous Treasury Stock, Value, Acquired, Cost Method Purchase of treasury stock-net Purchase of treasury stock Purchase of treasury stock (in shares) Treasury Stock, Shares, Acquired Treasury stock at cost, shares Treasury Stock, Shares TREASURY STOCK (Note 7) Treasury Stock Treasury Stock [Member] Treasury stock at cost; 23,824 and 98,944 shares at respective dates Treasury Stock, Value Unamortized debt issue costs Unamortized Debt Issuance Expense Unconditional Purchase Obligation, Category of Goods or Services Acquired [Domain] Change in derivative instruments fair value Unrealized Gain (Loss) on Derivatives Pre-tax interest expense (benefit) related to unrecognized tax benefits Unrecognized Tax Benefits, Interest on Income Taxes Expense Pre-tax interest benefit related to unrecognized tax benefits Accrued liabilities for interest related to unrecognized tax benefits Unrecognized Tax Benefits, Interest on Income Taxes Accrued Additions for tax positions of the current year Unrecognized Tax Benefits, Increase Resulting from Current Period Tax Positions Settlements with taxing authorities Settlements with taxing authorities Unrecognized Tax Benefits, Decrease Resulting from Settlements with Taxing Authorities Changes in judgment Unrecognized Tax Benefits, Decrease Resulting from Prior Period Tax Positions Unrecognized tax benefits if recognized, would decrease effective tax rate Unrecognized Tax Benefits that Would Impact Effective Tax Rate Lapses of applicable statute of limitations Unrecognized Tax Benefits, Reduction Resulting from Lapse of Applicable Statute of Limitations Total unrecognized tax benefits at the beginning of the year Total unrecognized tax benefits at the end of the year Unrecognized Tax Benefits Unrecognized Tax Benefits, Increase Resulting from Prior Period Tax Positions Additions for tax positions of prior years Change in unrecognized tax benefits Unrecognized Tax Benefits, Period Increase (Decrease) Contractual Obligations Unrecorded Unconditional Purchase Obligation, Fiscal Year Maturity [Abstract] 2013 Unrecorded Unconditional Purchase Obligation, Due in Remainder of Fiscal Year Schedule of updated contractual obligations related to the entity's fuel and purchased power obligations Unrecorded Unconditional Purchase Obligations Disclosure [Table Text Block] Thereafter Unrecorded Unconditional Purchase Obligation, Due after Five Years 2018 Unrecorded Unconditional Purchase Obligation, Due within Five Years Fuel and Purchased Power Commitments and Purchase Obligations Unrecorded Unconditional Purchase Obligation [Line Items] Total commitments Unrecorded Unconditional Purchase Obligation Actual purchases under commitment obligations Unrecorded Unconditional Purchase Obligation, Purchases 2014 Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months 2016 Unrecorded Unconditional Purchase Obligation, Due within Three Years Unrecorded Unconditional Purchase Obligation by Category of Item Purchased [Axis] 2015 Unrecorded Unconditional Purchase Obligation, Due within Two Years Unrecorded Unconditional Purchase Obligation [Table] 2017 Unrecorded Unconditional Purchase Obligation, Due within Four Years Accounting Records and Use of Estimates Use of Estimates, Policy [Policy Text Block] Municipality bonds US States and Political Subdivisions Debt Securities [Member] U.S. Treasury US Treasury Securities [Member] Operations and maintenance Utilities Operating Expense, Maintenance and Operations Utility Plant [Domain] Valuation and Qualifying Accounts Disclosure [Table] Valuation Allowances and Reserves [Domain] Additions, Charged to cost and expenses Valuation Allowances and Reserves, Charged to Cost and Expense Balance at beginning of period Balance at end of period Valuation Allowances and Reserves, Balance Valuation Technique [Domain] Valuation Technique [Axis] Deductions Valuation Allowances and Reserves, Deductions Additions, Charged to other accounts Valuation Allowances and Reserves, Charged to Other Accounts Reserve for uncollectibles Valuation and Qualifying Accounts Disclosure [Line Items] Valuation Allowances and Reserves Type [Axis] Palo Verde sale leaseback property plant and equipment, net of accumulated depreciation Palo Verde sale leaseback, net of accumulated depreciation (Note 6) Variable Interest Entity, Consolidated, Carrying Amount, Assets Variable Interest Entities [Axis] Consolidation of VIEs Palo Verde VIE Variable Interest Entity, Primary Beneficiary [Member] Palo Verde Sale Leaseback Variable Interest Entities Variable Interest Entity [Line Items] Amounts relating to the VIEs included in Condensed Consolidated Balance Sheets Variable Interest Entity, Classification of Carrying Amount, Assets and Liabilities, Net [Abstract] Palo Verde Sale Leaseback Variable Interest Entities Variable Interest Entity Disclosure [Text Block] Weighted Average Weighted Average [Member] Contingently issuable performance shares and restricted stock units Weighted Average Number of Shares, Restricted Stock Net effect of dilutive securities: Weighted Average Number of Shares Outstanding, Diluted [Abstract] WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - BASIC (in shares) Weighted Average Number of Shares Outstanding, Basic Average common shares outstanding - basic Statement of Income Net Income (Loss), Including Portion Attributable to Noncontrolling Interest [Abstract] Weighted Average Number of Shares Outstanding, Diluted WEIGHTED-AVERAGE COMMON SHARES OUTSTANDING - DILUTED (in shares) Average common shares outstanding - diluted