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Carrying amount as of the balance sheet date of the asset arising from commodity contracts related to natural gas which are expected to be settled within a year or normal operating cycle, if longer.

No definition available.

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Carrying amount as of the balance sheet date of the asset arising from commodity contracts related to electricity which are expected to be settled after a year or beyond the normal operating cycle, if longer.

No definition available.

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Carrying amount as of the balance sheet date of the asset arising from commodity contracts related to natural gas which are expected to be settled after a year or beyond the normal operating cycle, if longer.

No definition available.

Name:	por_CommodityContractAssetNoncurrentNaturalGas
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Carrying amount as of the balance sheet date of the liability arising from commodity contracts related to electricity which are expected to be settled within a year or the normal operating cycle, if longer.

No definition available.

Name:	por_CommodityContractLiabilityCurrentElectricity
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Carrying amount as of the balance sheet date of the liability arising from the commodity contracts related to natural gas which are expected to be settled within a year or normal operating cycle, if longer.

No definition available.

Name:	por_CommodityContractLiabilityCurrentNaturalGas
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Carrying amount as of the balance sheet date of the liability arising from commodity contracts related to electricity which are expected to be settled after a year or beyond the normal operating cycle, if longer.

No definition available.

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Carrying amount as of the balance sheet date of the liability arising from commodity contracts related to natural gas which are expected to be settled after a year or beyond the normal operating cycle, if longer.

No definition available.

Name:	por_CommodityContractLiabilityNoncurrentNaturalGas
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Commodity contracts: [Abstract]

No definition available.

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Fair valules as of the balance sheet date for all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be settled within one year or the normal operating cycle, if longer.

No definition available.

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Fair values as of the balance sheet date for all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be settled within one year of the normal operating cycle, if longer.

No definition available.

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Current Liabilities, Commodity Contracts: [Abstract]

No definition available.

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Fair values as of the balance sheet date of all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments.

No definition available.

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Fair values as of the balance sheet date of all liabilities resulting from contracts that meet the criteria of being accounted for as derivative instruments.

No definition available.

Name:	por_DerivativeLiabilitiesTotal
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Noncurrent Assets, Commodity Contracts: [Abstract]

No definition available.

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Fair values as of the balance sheet date for all assets resulting from contracts that meet the criteria of being accounted for as derivative instruments, and which are expected to be settled after one year or normal operating cycle, if longer.

No definition available.

Name:	por_NoncurrentDerivativeLiabilities
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Noncurrent Liabilities, Commodity Contracts: [Abstract]

No definition available.

Name:	por_NoncurrentLiabilitiesCommodityContractsAbstract
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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, expected to be settled after one year or the normal operating cycle, if longer. Includes assets not subject to a master netting arrangement and not elected to be offset.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
-Paragraph 6
-URI http://asc.fasb.org/extlink&oid=6945355&loc=d3e41271-113958

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 825
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-Section 50
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-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13433-108611

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 45
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Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 20
-Section 50
-Paragraph 3
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Reference 5: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
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-Section 50
-Paragraph 15
-URI http://asc.fasb.org/extlink&oid=77997519&loc=d3e13495-108611

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Fair value as of the balance sheet date of all price risk derivative assets not designated as hedging instruments.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624163-113959

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Fair value as of the balance sheet date of all price risk derivative liabilities not designated as hedging instruments.