XML 92 R77.htm IDEA: XBRL DOCUMENT
v3.20.4

Credit Facilities Schedule of Short term debt (Details) - USD ($) $ in Millions | 12 Months Ended
--- | ---
Dec. 31, 2020 | Dec. 31, 2019
Line of Credit Facility [Abstract] |  |
Average daily amount of short-term debt outstanding | $ 131 | $ 7
Weighted daily average interest rate | 1.50% | 2.60%
Maximum amount outstanding during the year | $ 225 | $ 46

X
- Definition Short-term Debt, Maximum amount outstanding during the year + References No definition available. + Details
Name: | por_ShortTermDebtMaximumAmountOutstandingDuringYear
Namespace Prefix: | por_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_LineOfCreditFacilityAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Weighted average interest rate of short-term debt outstanding calculated at point in time. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.19(b)) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 + Details
Name: | us-gaap_ShortTermDebtWeightedAverageInterestRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition For the form of debt having an initial term of less than one year or less than the normal operating cycle, if longer, average borrowings during the period. + References No definition available. + Details
Name: | us-gaap_ShorttermDebtAverageOutstandingAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration