XML 78 R65.htm IDEA: XBRL DOCUMENT
v3.20.2

Commitments and Contingencies - Environmental Matters and Financial Assurances (Details) - USD ($) $ in Millions |  |  | 6 Months Ended | 12 Months Ended
--- | --- | --- | --- | ---
Jul. 03, 2018 | Jul. 06, 2016 | Jun. 30, 2020 | Dec. 31, 2019
Financial Assurances |  |  |  |
Equity contribution guarantees |  |  | $ 40.0 |
APS | Letters of Credit Expiring in 2020 |  |  |  |
Financial Assurances |  |  |  |
Outstanding letters of credit |  |  | 4.9 |
APS | Surety Bonds Expiring in 2020 |  |  |  |
Financial Assurances |  |  |  |
Surety bonds expiring, amount |  |  | 16.0 |
4C Acquisition, LLC | Four Corners |  |  |  |
Environmental Matters |  |  |  |
Percentage of share of cost of control |  | 7.00% |  |
Four Corners Coal Supply Agreement |  |  |  |
Notes receivable, related parties |  |  | 39.0 |
4C Acquisition, LLC | Coal Supply Agreement Arbitration | Four Corners |  |  |  |
Four Corners Coal Supply Agreement |  |  |  |
Reimbursement payments due to 4CA |  |  | $ 10.0 |
NTEC | Four Corners |  |  |  |
Four Corners Coal Supply Agreement |  |  |  |
Option to purchase ownership interest (as a percent) | 7.00% | 7.00% |  |
Proceeds from operating and maintenance cost reimbursement | $ 70.0 |  |  |
NTEC | Coal Supply Agreement Arbitration | Four Corners |  |  |  |
Four Corners Coal Supply Agreement |  |  |  |
Option to purchase ownership interest (as a percent) |  | 7.00% |  |
Regional Haze Rules | APS | Four Corners Units 4 and 5 |  |  |  |
Environmental Matters |  |  |  |
Percentage of share of cost of control |  |  | 63.00% |
Expected environmental cost |  |  | $ 400.0 |
Regional Haze Rules | APS | Natural gas tolling contract obligations | Four Corners Units 4 and 5 |  |  |  |
Environmental Matters |  |  |  |
Additional percentage share of cost of control |  |  | 7.00% |
Regional Haze Rules | APS | Four Corners | Four Corners Units 4 and 5 |  |  |  |
Environmental Matters |  |  |  |
Site contingency increase in loss exposure not accrued, best estimate |  |  | $ 45.0 |
Coal combustion waste | APS | Four Corners |  |  |  |
Environmental Matters |  |  |  |
Site contingency increase in loss exposure not accrued, best estimate |  |  | 22.0 |
Coal combustion waste | APS | Navajo Plant |  |  |  |
Environmental Matters |  |  |  |
Site contingency increase in loss exposure not accrued, best estimate |  |  | 1.0 |
Minimum | Coal combustion waste | APS | Cholla |  |  |  |
Environmental Matters |  |  |  |
Site contingency increase in loss exposure not accrued, best estimate |  |  | $ 15.0 |
Minimum | Coal combustion waste | APS | Cholla and Four Corners |  |  |  |
Environmental Matters |  |  |  |
Site contingency increase in loss exposure not accrued, best estimate |  |  |  | $ 10.0
Maximum | Coal combustion waste | APS | Cholla and Four Corners |  |  |  |
Environmental Matters |  |  |  |
Site contingency increase in loss exposure not accrued, best estimate |  |  |  | $ 15.0

X
- Definition Asset Purchase Agreement, Additional Percentage Share of Cost of Control + References No definition available. + Details
Name: | pnw_AssetPurchaseAgreementAdditionalPercentageShareofCostofControl
Namespace Prefix: | pnw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Asset Purchase Agreement, Operating and Maintenance Cost Reimbursement Receivable + References No definition available. + Details
Name: | pnw_AssetPurchaseAgreementOperatingandMaintenanceCostReimbursementReceivable
Namespace Prefix: | pnw_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Asset Purchase Agreement, Option to Purchase, Ownership Interest, Percentage + References No definition available. + Details
Name: | pnw_AssetPurchaseAgreementOptiontoPurchaseOwnershipInterestPercentage
Namespace Prefix: | pnw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Asset Purchase Agreement, Proceeds from Operating an Maintenance Cost Reimbursement + References No definition available. + Details
Name: | pnw_AssetPurchaseAgreementProceedsfromOperatinganMaintenanceCostReimbursement
Namespace Prefix: | pnw_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Asset Purchase Agreement, Site Contingency, Increase in Loss Exposure Not Accrued, Best Estimate + References No definition available. + Details
Name: | pnw_AssetPurchaseAgreementSiteContingencyIncreaseinLossExposureNotAccruedBestEstimate
Namespace Prefix: | pnw_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Definition Equity Contribution Guarantees + References No definition available. + Details
Name: | pnw_EquityContributionGuarantees
Namespace Prefix: | pnw_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- References No definition available. + Details
Name: | pnw_FinancialAssurancesAbstract
Namespace Prefix: | pnw_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the percentage of share of the cost of control acquired by the entity. + References No definition available. + Details
Name: | pnw_PercentageOfShareOfCostOfControl
Namespace Prefix: | pnw_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Supply Agreement [Abstract] + References No definition available. + Details
Name: | pnw_SupplyAgreementAbstract
Namespace Prefix: | pnw_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Surety Bonds Expiring, Amount + References No definition available. + Details
Name: | pnw_SuretyBondsExpiringAmount
Namespace Prefix: | pnw_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The total amount of the contingent obligation under letters of credit outstanding as of the reporting date. + References No definition available. + Details
Name: | us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition For an unclassified balance sheet, amounts due from parties associated with the reporting entity as evidenced by a written promise to pay. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 235 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.4-08.(k)(1)) -URI http://asc.fasb.org/extlink&oid=120395691&loc=d3e23780-122690 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.3) -URI http://asc.fasb.org/extlink&oid=120400017&loc=d3e572229-122910 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 850 -SubTopic 10 -Section 50 -Paragraph 1 -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=6457730&loc=d3e39549-107864 + Details
Name: | us-gaap_NotesReceivableRelatedParties
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table. + References No definition available. + Details
Name: | us-gaap_SiteContingencyLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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://fasb.org/us-gaap/role/ref/legacyRef -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 Reference 2: http://www.xbrl.org/2003/role/recommendedDisclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 10 -Subparagraph (d)(2) -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13237-110859 + Details
Name: | us-gaap_SiteContingencyLossExposureNotAccruedBestEstimate
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- Details
Name: | dei_LegalEntityAxis=pnw_ArizonaPublicServiceCompanyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=pnw_LettersofCreditExpiringin2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_DebtInstrumentAxis=pnw_SuretyBondsExpiringin2020Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=pnw_A4CAcquisitionLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_JointlyOwnedUtilityPlantAxis=pnw_FourCornersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_LitigationCaseAxis=pnw_CoalSupplyAgreementArbitrationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=pnw_NavajoTransitionalEnergyCompanyLLCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EnvironmentalRemediationContingencyAxis=pnw_RegionalHazeRulesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_JointlyOwnedUtilityPlantAxis=pnw_FourCornersUnits4And5Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_CreditFacilityAxis=pnw_NaturalGasTollingLetterOfCreditMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EnvironmentalRemediationSiteAxis=pnw_FourCornersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EnvironmentalRemediationContingencyAxis=pnw_CoalCombustionWasteMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EnvironmentalRemediationSiteAxis=pnw_NavajoGeneratingStationMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EnvironmentalRemediationSiteAxis=pnw_ChollaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_EnvironmentalRemediationSiteAxis=pnw_ChollaandFourCornersMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | srt_RangeAxis=srt_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |