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Commitments and Contingencies - Environmental Matters and Financial Assurances (Details) (USD $) | 3 Months Ended | 0 Months Ended
--- | --- | ---
Mar. 31, 2015 | May 23, 2013
Arizona Public Service Company | Four Corners Units 4 and 5 |  |
Environmental Matters |  |
Percentage of share of cost of control | 63.00%pnw_PercentageOfShareOfCostOfControl / us-gaap_JointlyOwnedUtilityPlantAxis = pnw_FourCornersUnits4And5Member / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Expected environmental cost | $ 400,000,000 us-gaap_SiteContingencyLossExposureNotAccruedBestEstimate / us-gaap_JointlyOwnedUtilityPlantAxis = pnw_FourCornersUnits4And5Member / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Cholla | Arizona Public Service Company |  |
Environmental Matters |  |
Expected environmental cost | 200,000,000 us-gaap_SiteContingencyLossExposureNotAccruedBestEstimate / us-gaap_EnvironmentalRemediationSiteAxis = pnw_ChollaMember / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Site contingency increase in loss exposure not accrued, best estimate | 85,000,000 pnw_AssetPurchaseAgreementSiteContingencyIncreaseinLossExposureNotAccruedBestEstimate / us-gaap_EnvironmentalRemediationSiteAxis = pnw_ChollaMember / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Four Corners | New Mexico Tax Matter |  |
Environmental Matters |  |
Coal severance surtax, penalty, and interest |  | 30,000,000 pnw_LossContingencyCoalSeveranceSurtaxPenaltyAndInterest / us-gaap_EnvironmentalRemediationSiteAxis = pnw_FourCornersMember / us-gaap_LitigationCaseAxis = pnw_NewMexicoTaxMatterMember
Four Corners | Arizona Public Service Company |  |
Environmental Matters |  |
Site contingency increase in loss exposure not accrued, best estimate | 15,000,000 pnw_AssetPurchaseAgreementSiteContingencyIncreaseinLossExposureNotAccruedBestEstimate / us-gaap_EnvironmentalRemediationSiteAxis = pnw_FourCornersMember / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Four Corners | Arizona Public Service Company | Four Corners Units 4 and 5 |  |
Environmental Matters |  |
Site contingency increase in loss exposure not accrued, best estimate | 45,000,000 pnw_AssetPurchaseAgreementSiteContingencyIncreaseinLossExposureNotAccruedBestEstimate / us-gaap_EnvironmentalRemediationSiteAxis = pnw_FourCornersMember / us-gaap_JointlyOwnedUtilityPlantAxis = pnw_FourCornersUnits4And5Member / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Four Corners | Arizona Public Service Company | New Mexico Tax Matter |  |
Environmental Matters |  |
Share of the assessment |  | 12,000,000 pnw_LossContingencyAssessmentShare / us-gaap_EnvironmentalRemediationSiteAxis = pnw_FourCornersMember / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember / us-gaap_LitigationCaseAxis = pnw_NewMexicoTaxMatterMember
Navajo Plant | Arizona Public Service Company |  |
Environmental Matters |  |
Expected environmental cost | 200,000,000 us-gaap_SiteContingencyLossExposureNotAccruedBestEstimate / us-gaap_EnvironmentalRemediationSiteAxis = pnw_NavajoGeneratingStationMember / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Site contingency increase in loss exposure not accrued, best estimate | 1,000,000 pnw_AssetPurchaseAgreementSiteContingencyIncreaseinLossExposureNotAccruedBestEstimate / us-gaap_EnvironmentalRemediationSiteAxis = pnw_NavajoGeneratingStationMember / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Cholla Units 2 And 3 | Arizona Public Service Company |  |
Environmental Matters |  |
Expected environmental cost | 130,000,000 us-gaap_SiteContingencyLossExposureNotAccruedBestEstimate / us-gaap_EnvironmentalRemediationSiteAxis = pnw_ChollaUnits2And3Member / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Letter of Credit | Arizona Public Service Company |  |
Financial Assurances |  |
Outstanding letters of credit | 109,000,000 us-gaap_LettersOfCreditOutstandingAmount / us-gaap_CreditFacilityAxis = us-gaap_LetterOfCreditMember / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Equity Lessors in Palo Verde sale leaseback transactions | Arizona Public Service Company |  |
Financial Assurances |  |
Outstanding letters of credit | 20,000,000 us-gaap_LettersOfCreditOutstandingAmount / us-gaap_CreditFacilityAxis = pnw_EquityLessorsSaleLeasebackLetterOfCreditMember / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Natural gas tolling contract obligations | Arizona Public Service Company |  |
Financial Assurances |  |
Outstanding letters of credit | $ 5,000,000 us-gaap_LettersOfCreditOutstandingAmount / us-gaap_CreditFacilityAxis = pnw_NaturalGasTollingLetterOfCreditMember / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Natural gas tolling contract obligations | Arizona Public Service Company | Four Corners Units 4 and 5 |  |
Environmental Matters |  |
Additional percentage share of cost of control | 7.00%pnw_AssetPurchaseAgreementAdditionalPercentageShareofCostofControl / us-gaap_CreditFacilityAxis = pnw_NaturalGasTollingLetterOfCreditMember / us-gaap_JointlyOwnedUtilityPlantAxis = pnw_FourCornersUnits4And5Member / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Letters of Credit Expiring in 2015 | Arizona Public Service Company |  |
Financial Assurances |  |
Number of letters of credit expiring | 1 pnw_NumberOfLettersOfCreditExpiring / us-gaap_DebtInstrumentAxis = pnw_LettersOfCreditExpiringIn2015Member / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |
Letters of Credit Expiring in 2016 | Arizona Public Service Company |  |
Financial Assurances |  |
Number of letters of credit expiring | 2 pnw_NumberOfLettersOfCreditExpiring / us-gaap_DebtInstrumentAxis = pnw_LettersOfCreditExpiringIn2016Member / dei_LegalEntityAxis = pnw_ArizonaPublicServiceCompanyMember |

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- Definition Represent information pertaining to total amount of coal severance surtax, penalty, and interest related to coal supplied under the coal supply agreement. + References No definition available. + Details
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- Definition Best estimate of the loss exposure for reasonably possible environmental contingencies at an individual site for which no accrual has been recorded. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 10 -Subparagraph (c),(d)(2) -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13237-110859 + Details
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