Name:	pnw_DerivativeInstrumentsGainLossReclassifiedFromAccumulatedOCIIntoIncomeOnDiscontinuation
Namespace Prefix:	pnw_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

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.

No definition available.

Name:	pnw_NonDerivativeCreditRiskContractAdditionalCollateralAggregateFairValue
Namespace Prefix:	pnw_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

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.

No definition available.

Name:	pnw_PercentageOfUnrealizedGainsAndLossesOnCertainDerivativesDeferredForFutureRateTreatment
Namespace Prefix:	pnw_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994

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Period Type:	duration

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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 860
-SubTopic 20
-Section 50
-Paragraph 4D
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=64830801&loc=SL51823488-111719

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-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 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (a),(c)
-URI http://asc.fasb.org/extlink&oid=64837297&loc=SL5624163-113959

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 55
-Paragraph 7
-URI http://asc.fasb.org/extlink&oid=51825145&loc=SL20226000-175313

Name:	us-gaap_DerivativeFairValueOfDerivativeLiability
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

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.

No definition available.