XML 86 R71.htm IDEA: XBRL DOCUMENT
v3.20.4

Counterparties representing 10% or more (Details) | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019
Liabilities from price risk management activities: [Abstract] |  |
Concentration of Risk, Derivative Instruments, Assets | 66.00% | 70.00%
Counterparty A [Member] |  |
Liabilities from price risk management activities: [Abstract] |  |
Concentration Risk, Percentage | 12.00% | 35.00%
Counterparty B [Member] |  |
Liabilities from price risk management activities: [Abstract] |  |
Concentration Risk, Percentage | 17.00% | 13.00%
Counterparty C [Member] |  |
Liabilities from price risk management activities: [Abstract] |  |
Concentration Risk, Percentage | 21.00% | 11.00%
Counterparty D [Member] |  |
Liabilities from price risk management activities: [Abstract] |  |
Concentration Risk, Percentage | 16.00% | 11.00%
Counterparty F [Member] |  |
Liabilities from price risk management activities: [Abstract] |  |
Concentration Risk, Percentage | 93.00% | 79.00%

X
- Definition Represents aggregate of individually significant counterparties of total assets arising from derivative instruments from price risk management activities. + References No definition available. + Details
Name: | por_ConcentrationOfRiskDerivativeInstrumentsAssets
Namespace Prefix: | por_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Liabilities from price risk management activities: [Abstract] + References No definition available. + Details
Name: | por_LiabilitiesFromPriceRiskManagementActivitiesAbstract
Namespace Prefix: | por_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- 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/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 280 -SubTopic 10 -Section 50 -Paragraph 42 -URI http://asc.fasb.org/extlink&oid=120311839&loc=d3e9054-108599 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 18 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6351-108592 Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13531-108611 Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 50 -Paragraph 21 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=121572278&loc=d3e13537-108611 Reference 5: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 275 -SubTopic 10 -Section 50 -Paragraph 20 -URI http://asc.fasb.org/extlink&oid=99393423&loc=d3e6404-108592 + Details
Name: | us-gaap_ConcentrationRiskPercentage1
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=por_CounterpartyAMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=por_CounterpartyBMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=por_CounterpartyCMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=por_CounterpartyDMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_ConcentrationRiskByTypeAxis=por_CounterpartyFMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |