XML 1054 R86.htm IDEA: XBRL DOCUMENT v2.4.1.9
Commitments and Contingencies Commitments and Contingencies - Environmental Matters and Financial Assurances (Details) (USD $)
12 Months Ended 0 Months Ended
Dec. 31, 2014
May 23, 2013
Four Corners | ARIZONA PUBLIC SERVICE COMPANY    
Environmental Matters [Abstract]    
Additional expected environment cost $ 15,000,000pnw_AssetPurchaseAgreementSiteContingencyIncreaseinLossExposureNotAccruedBestEstimate
/ us-gaap_EnvironmentalRemediationSiteAxis
= pnw_FourCornersMember
/ dei_LegalEntityAxis
= pnw_ArizonaPublicServiceCompanyMember
 
Cholla | ARIZONA PUBLIC SERVICE COMPANY    
Environmental Matters [Abstract]    
Additional expected environment cost 85,000,000pnw_AssetPurchaseAgreementSiteContingencyIncreaseinLossExposureNotAccruedBestEstimate
/ us-gaap_EnvironmentalRemediationSiteAxis
= pnw_ChollaMember
/ dei_LegalEntityAxis
= pnw_ArizonaPublicServiceCompanyMember
 
Cholla Units 1-3 | ARIZONA PUBLIC SERVICE COMPANY    
Environmental Matters [Abstract]    
Expected environmental cost 130,000,000us-gaap_SiteContingencyLossExposureNotAccruedBestEstimate
/ us-gaap_EnvironmentalRemediationSiteAxis
= pnw_ChollaUnits1To3Member
/ dei_LegalEntityAxis
= pnw_ArizonaPublicServiceCompanyMember
 
New Mexico Tax Matter | Four Corners    
Environmental Matters [Abstract]    
Coal severance surtax, penalty, and interest   30,000,000pnw_LossContingencyCoalSeveranceSurtaxPenaltyAndInterest
/ us-gaap_EnvironmentalRemediationSiteAxis
= pnw_FourCornersMember
/ us-gaap_LitigationCaseAxis
= pnw_NewMexicoTaxMatterMember
New Mexico Tax Matter | Four Corners | ARIZONA PUBLIC SERVICE COMPANY    
Environmental Matters [Abstract]    
Share of the assessment   12,000,000pnw_LossContingencyAssessmentShare
/ us-gaap_EnvironmentalRemediationSiteAxis
= pnw_FourCornersMember
/ dei_LegalEntityAxis
= pnw_ArizonaPublicServiceCompanyMember
/ us-gaap_LitigationCaseAxis
= pnw_NewMexicoTaxMatterMember
Letter of credit | ARIZONA PUBLIC SERVICE COMPANY    
Financial Assurances    
Outstanding letters of credit 109,000,000us-gaap_LettersOfCreditOutstandingAmount
/ us-gaap_CreditFacilityAxis
= us-gaap_LetterOfCreditMember
/ dei_LegalEntityAxis
= pnw_ArizonaPublicServiceCompanyMember
 
Equity Lessors Sale Leaseback Letter of Credit | ARIZONA PUBLIC SERVICE COMPANY    
Financial Assurances    
Outstanding letters of credit 23,000,000us-gaap_LettersOfCreditOutstandingAmount
/ us-gaap_CreditFacilityAxis
= pnw_EquityLessorsSaleLeasebackLetterOfCreditMember
/ dei_LegalEntityAxis
= pnw_ArizonaPublicServiceCompanyMember
 
Natural Gas Tolling Letter of Credit | ARIZONA PUBLIC SERVICE COMPANY    
Financial Assurances    
Outstanding letters of credit 5,000,000us-gaap_LettersOfCreditOutstandingAmount
/ us-gaap_CreditFacilityAxis
= pnw_NaturalGasTollingLetterOfCreditMember
/ dei_LegalEntityAxis
= pnw_ArizonaPublicServiceCompanyMember
 
Four Corners Units 4 and 5 | Four Corners | ARIZONA PUBLIC SERVICE COMPANY    
Environmental Matters [Abstract]    
Additional expected environment cost 40,000,000pnw_AssetPurchaseAgreementSiteContingencyIncreaseinLossExposureNotAccruedBestEstimate
/ us-gaap_EnvironmentalRemediationSiteAxis
= pnw_FourCornersMember
/ us-gaap_JointlyOwnedUtilityPlantAxis
= pnw_FourCornersUnits4And5Member
/ dei_LegalEntityAxis
= pnw_ArizonaPublicServiceCompanyMember
 
Four Corners Units 4 and 5 | Navajo Plant | ARIZONA PUBLIC SERVICE COMPANY    
Environmental Matters [Abstract]    
Expected environmental cost 200,000,000us-gaap_SiteContingencyLossExposureNotAccruedBestEstimate
/ us-gaap_EnvironmentalRemediationSiteAxis
= pnw_NavajoPlantMember
/ us-gaap_JointlyOwnedUtilityPlantAxis
= pnw_FourCornersUnits4And5Member
/ dei_LegalEntityAxis
= pnw_ArizonaPublicServiceCompanyMember
 
Four Corners Units 4 and 5 | Cholla | ARIZONA PUBLIC SERVICE COMPANY    
Environmental Matters [Abstract]    
Expected environmental cost 200,000,000us-gaap_SiteContingencyLossExposureNotAccruedBestEstimate
/ us-gaap_EnvironmentalRemediationSiteAxis
= pnw_ChollaMember
/ us-gaap_JointlyOwnedUtilityPlantAxis
= pnw_FourCornersUnits4And5Member
/ dei_LegalEntityAxis
= pnw_ArizonaPublicServiceCompanyMember
 
Four Corners Units 4 and 5 | Natural Gas Tolling Letter of Credit | ARIZONA PUBLIC SERVICE COMPANY    
Environmental Matters [Abstract]    
Percentage of share of cost of control 63.00%pnw_PercentageOfShareOfCostOfControl
/ us-gaap_CreditFacilityAxis
= pnw_NaturalGasTollingLetterOfCreditMember
/ us-gaap_JointlyOwnedUtilityPlantAxis
= pnw_FourCornersUnits4And5Member
/ dei_LegalEntityAxis
= pnw_ArizonaPublicServiceCompanyMember
 
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
 
Minimum | Four Corners Units 4 and 5 | Four Corners | ARIZONA PUBLIC SERVICE COMPANY    
Environmental Matters [Abstract]    
Expected environmental cost $ 350,000,000us-gaap_SiteContingencyLossExposureNotAccruedBestEstimate
/ us-gaap_EnvironmentalRemediationSiteAxis
= pnw_FourCornersMember
/ us-gaap_JointlyOwnedUtilityPlantAxis
= pnw_FourCornersUnits4And5Member
/ dei_LegalEntityAxis
= pnw_ArizonaPublicServiceCompanyMember
/ us-gaap_RangeAxis
= us-gaap_MinimumMember