XML 81 R68.htm IDEA: XBRL DOCUMENT
v3.20.2

Fair Value Measurements - Assets and Liabilities Measured on a Recurring Basis (Details) - USD ($) $ in Thousands | Jun. 30, 2020 | Dec. 31, 2019
--- | --- | ---
Assets |  |
Commodity contracts, assets | $ 740 | $ 515
Commodity contracts, liabilities | (2,790) | (69)
Nuclear decommissioning trust | 1,024,033 | 1,010,775
Nuclear decommissioning trust, other | 496,121 | 521,245
Other special use funds | 253,332 | 245,095
Other special use funds, other | 526 | 474
Total assets | 1,278,105 | 1,256,385
Total assets, other | 493,857 | 521,650
Liabilities |  |
Total, other | 1,605 | 711
Amount reported on balance sheet | (70,986) | (72,132)
Equity securities |  |
Assets |  |
Nuclear decommissioning trust | 9,855 | 13,273
Nuclear decommissioning trust, other | (6,130) | 2,401
Other special use funds | 9,481 | 7,616
Other special use funds, other | 526 | 474
U.S. commingled equity funds |  |
Assets |  |
Nuclear decommissioning trust | 502,251 | 518,844
U.S. Treasury debt |  |
Assets |  |
Nuclear decommissioning trust | 143,673 | 160,607
Other special use funds | 229,858 | 232,848
Corporate debt |  |
Assets |  |
Nuclear decommissioning trust | 149,672 | 115,869
Mortgage-backed securities |  |
Assets |  |
Nuclear decommissioning trust | 99,407 | 118,795
Municipal bonds |  |
Assets |  |
Nuclear decommissioning trust | 106,971 | 73,040
Other special use funds | 13,993 | 4,631
Other fixed income |  |
Assets |  |
Nuclear decommissioning trust | 12,204 | 10,347
Level 1 |  |
Assets |  |
Commodity contracts, assets | 0 | 0
Nuclear decommissioning trust | 159,658 | 171,479
Other special use funds | 238,813 | 239,990
Total assets | 398,471 | 411,469
Liabilities |  |
Gross derivative liability | 0 | 0
Level 1 | Equity securities |  |
Assets |  |
Nuclear decommissioning trust | 15,985 | 10,872
Other special use funds | 8,955 | 7,142
Level 1 | U.S. commingled equity funds |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Level 1 | U.S. Treasury debt |  |
Assets |  |
Nuclear decommissioning trust | 143,673 | 160,607
Other special use funds | 229,858 | 232,848
Level 1 | Corporate debt |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Level 1 | Mortgage-backed securities |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Level 1 | Municipal bonds |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Other special use funds | 0 | 0
Level 1 | Other fixed income |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Level 2 |  |
Assets |  |
Commodity contracts, assets | 3,165 | 551
Nuclear decommissioning trust | 368,254 | 318,051
Other special use funds | 13,993 | 4,631
Total assets | 385,412 | 323,233
Liabilities |  |
Gross derivative liability | (61,974) | (67,992)
Level 2 | Equity securities |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Other special use funds | 0 | 0
Level 2 | U.S. commingled equity funds |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Level 2 | U.S. Treasury debt |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Other special use funds | 0 | 0
Level 2 | Corporate debt |  |
Assets |  |
Nuclear decommissioning trust | 149,672 | 115,869
Level 2 | Mortgage-backed securities |  |
Assets |  |
Nuclear decommissioning trust | 99,407 | 118,795
Level 2 | Municipal bonds |  |
Assets |  |
Nuclear decommissioning trust | 106,971 | 73,040
Other special use funds | 13,993 | 4,631
Level 2 | Other fixed income |  |
Assets |  |
Nuclear decommissioning trust | 12,204 | 10,347
Level 3 |  |
Assets |  |
Commodity contracts, assets | 365 | 33
Nuclear decommissioning trust | 0 | 0
Other special use funds | 0 | 0
Total assets | 365 | 33
Liabilities |  |
Gross derivative liability | (10,617) | (3,429)
Level 3 | Equity securities |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Other special use funds | 0 | 0
Level 3 | U.S. commingled equity funds |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Level 3 | U.S. Treasury debt |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Other special use funds | 0 | 0
Level 3 | Corporate debt |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Level 3 | Mortgage-backed securities |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Level 3 | Municipal bonds |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Other special use funds | 0 | 0
Level 3 | Other fixed income |  |
Assets |  |
Nuclear decommissioning trust | 0 | 0
Fair Value Measured at Net Asset Value Per Share | U.S. commingled equity funds |  |
Assets |  |
Nuclear decommissioning trust | $ 502,251 | $ 518,844

X
- Definition Assets, Fair Value, Gross Liability and Net Pending Securities Sales and Purchases + References No definition available. + Details
Name: | pnw_AssetsFairValueGrossLiabilityandNetPendingSecuritiesSalesandPurchases
Namespace Prefix: | pnw_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Decommissioning Fund Investments, Fair Value Net Pending Securities Sales and Purchases + References No definition available. + Details
Name: | pnw_DecommissioningFundInvestmentsFairValueNetPendingSecuritiesSalesandPurchases
Namespace Prefix: | pnw_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Special Use Fund Investments, Other, Gross Fair Value + References No definition available. + Details
Name: | pnw_SpecialUseFundInvestmentsOtherGrossFairValue
Namespace Prefix: | pnw_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Special Use Fund Investments, Other, Net Fair Value Pending Sales and Purchases + References No definition available. + Details
Name: | pnw_SpecialUseFundInvestmentsOtherNetFairValuePendingSalesandPurchases
Namespace Prefix: | pnw_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value portion of probable future economic benefits obtained or controlled by an entity as a result of past transactions or events. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=117815213&loc=d3e19207-110258 + Details
Name: | us-gaap_AssetsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Definition The fair value of investments held in a trust fund to pay for the costs of decontaminating and decommissioning facilities, whether such amount is presented as a separate caption or as a parenthetical disclosure on the balance sheet. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6392692&loc=d3e7535-110849 + Details
Name: | us-gaap_DecommissioningTrustAssetsAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226003-175313 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 + Details
Name: | us-gaap_DerivativeAssetFairValueGrossLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value, before effects of master netting arrangements, of a financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes assets elected not to be offset. Excludes assets not subject to a master netting arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4D -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=121570589&loc=SL51823488-111719 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959 + Details
Name: | us-gaap_DerivativeFairValueOfDerivativeAsset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Fair value, before effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities elected not to be offset. Excludes liabilities not subject to a master netting arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 860 -SubTopic 20 -Section 50 -Paragraph 4D -Subparagraph (c)(2) -URI http://asc.fasb.org/extlink&oid=121570589&loc=SL51823488-111719 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 7 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226000-175313 + Details
Name: | us-gaap_DerivativeFairValueOfDerivativeLiability
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value, after the effects of master netting arrangements, of a financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. Includes liabilities not subject to a master netting arrangement and not elected to be offset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13433-108611 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 10 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226008-175313 + Details
Name: | us-gaap_DerivativeLiabilities
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Fair value of asset associated with financial liability or contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 50 -Paragraph 3 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=51824906&loc=SL20225862-175312 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 20 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=99393222&loc=SL20226003-175313 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4B -Subparagraph (a),(c) -URI http://asc.fasb.org/extlink&oid=121590274&loc=SL5624163-113959 + Details
Name: | us-gaap_DerivativeLiabilityFairValueGrossAsset
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_EquitySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=pnw_USCommingledFundsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USTreasurySecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_CorporateDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_MortgageBackedSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_USStatesAndPoliticalSubdivisionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FinancialInstrumentAxis=us-gaap_OtherDebtSecuritiesMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel1Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel2Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueInputsLevel3Member
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_FairValueByFairValueHierarchyLevelAxis=us-gaap_FairValueMeasuredAtNetAssetValuePerShareMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |