Derivative Accounting - Narrative (Details) $ in Thousands	9 Months Ended
Sep. 30, 2015 USD ($) Counterparty	Dec. 31, 2014 USD ($)
Derivative Accounting
Percentage of deferred unrealized gains (losses) on contracts due to PSA recovery	100.00%
Designated as Hedging Instruments
Derivative Accounting
Gross recognized derivatives	$ 4,000	$ 4,000
Commodity Contracts
Derivative Accounting
Gross recognized derivatives	$ 200,001	169,052
Concentration of credit risk, number of counterparties \| Counterparty	1
Concentration of risk with two counterparties, as a percentage of risk management assets	91.00%
Risk management activities-derivative instruments: Commodity Contracts	$ 28,962	$ 31,405
Additional collateral to counterparties for energy related non-derivative instrument contracts	161,000
Commodity Contracts \| Designated as Hedging Instruments
Derivative Accounting
Estimated net gain (loss) before income taxes to be reclassified from accumulated other comprehensive income	$ (4,000)
Arizona Public Service Company
Derivative Accounting
Percentage of unrealized gains and losses on certain derivatives deferred for future rate treatment	100.00%

The number of counterparties involved in risk management contracts for which the concentration of risk is disclosed.

No definition available.

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- Definition

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.

+ References

No definition available.

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- Definition

Percent Deferral of Unrealized Gain (Loss) on Certain Contracts Due to Changes in PSA Recovery

+ References

No definition available.

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- Definition

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.

+ References

No definition available.

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- Definition

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.

+ References

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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- Definition

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 275

-SubTopic 10

-Section 50

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- Definition

Fair value, after the 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 not subject to a master netting arrangement and not elected to be offset.

+ References

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 20

-Section 50

-Paragraph 3

-Subparagraph (c)

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- 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

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 4D

-Subparagraph (c)(2)

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- 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.

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