XML 107 R93.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Commitments and Guarantees Unrecorded Unconditional Purchase Obligations (Details) $ in Millions | Dec. 31, 2017 USD ($)
--- | ---
Capital Addition Purchase Commitments [Member] |
Unrecorded Unconditional Purchase Obligation [Line Items] |
Unrecorded Unconditional Purchase Obligation | $ 265
Unrecorded Unconditional Purchase Obligation, Due within One Year | 191
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 2
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 10
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 2
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 2
Unrecorded Unconditional Purchase Obligation, Due after Five Years | 58
Long-term Contract for Purchase of Electric Power [Domain] |
Unrecorded Unconditional Purchase Obligation [Line Items] |
Unrecorded Unconditional Purchase Obligation | 2,633
Unrecorded Unconditional Purchase Obligation, Due within One Year | 156
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 156
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 201
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 200
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 187
Unrecorded Unconditional Purchase Obligation, Due after Five Years | 1,733
Electric Transmission [Member] |
Unrecorded Unconditional Purchase Obligation [Line Items] |
Unrecorded Unconditional Purchase Obligation | 31
Unrecorded Unconditional Purchase Obligation, Due within One Year | 6
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 5
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 4
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 4
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 4
Unrecorded Unconditional Purchase Obligation, Due after Five Years | 8
Public Utility Districts [Member] |
Unrecorded Unconditional Purchase Obligation [Line Items] |
Unrecorded Unconditional Purchase Obligation | 158
Unrecorded Unconditional Purchase Obligation, Due within One Year | 9
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 17
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 16
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 16
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 15
Unrecorded Unconditional Purchase Obligation, Due after Five Years | 85
Natural gas [Member] |
Unrecorded Unconditional Purchase Obligation [Line Items] |
Unrecorded Unconditional Purchase Obligation | 303
Unrecorded Unconditional Purchase Obligation, Due within One Year | 51
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 35
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 28
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 25
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 24
Unrecorded Unconditional Purchase Obligation, Due after Five Years | 140
Coal and transportationSupply Agreements [Member] |
Unrecorded Unconditional Purchase Obligation [Line Items] |
Unrecorded Unconditional Purchase Obligation | 20
Unrecorded Unconditional Purchase Obligation, Due within One Year | 15
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 5
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 0
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 0
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 0
Unrecorded Unconditional Purchase Obligation, Due after Five Years | 0
Commitments [Member] |
Unrecorded Unconditional Purchase Obligation [Line Items] |
Unrecorded Unconditional Purchase Obligation | 3,410
Unrecorded Unconditional Purchase Obligation, Due within One Year | 428
Unrecorded Unconditional Purchase Obligation, Due within Two Years | 220
Unrecorded Unconditional Purchase Obligation, Due within Three Years | 259
Unrecorded Unconditional Purchase Obligation, Due within Four Years | 247
Unrecorded Unconditional Purchase Obligation, Due within Five Years | 232
Unrecorded Unconditional Purchase Obligation, Due after Five Years | $ 2,024

X
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 440 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77896938&loc=d3e25336-109308 + Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnFifthAnniversary
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 440 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77896938&loc=d3e25336-109308 + Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnFirstAnniversary
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the fourth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 440 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77896938&loc=d3e25336-109308 + Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnFourthAnniversary
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 440 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77896938&loc=d3e25336-109308 + Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnSecondAnniversary
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 440 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77896938&loc=d3e25336-109308 + Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceOnThirdAnniversary
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of the unrecorded obligation to transfer funds in the future for fixed or minimum amounts or quantities of goods or services at fixed or minimum prices (for example, as in take-or-pay contracts or throughput contracts). + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 440 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77896938&loc=d3e25336-109308 + Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationBalanceSheetAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount of the fixed and determinable portion of the unrecorded unconditional purchase obligation maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 440 -SubTopic 10 -Section 50 -Paragraph 4 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=77896938&loc=d3e25336-109308 + Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationDueAfterFiveYears
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- 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. + Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis=us-gaap_CapitalAdditionsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis=us-gaap_LongTermContractForPurchaseOfElectricPowerDomain
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis=us-gaap_ElectricTransmissionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis=por_PublicUtilityDistrictsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis=us-gaap_PublicUtilitiesInventoryFuelMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis=us-gaap_CoalSupplyAgreementsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_UnrecordedUnconditionalPurchaseObligationByCategoryOfItemPurchasedAxis=us-gaap_CommitmentsMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |