XML 54 R39.htm IDEA: XBRL DOCUMENT
v3.20.4

Summary of Significant Accounting Policies (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2020
Summary of Significant Accounting Policies [Abstract] |
Estimated average service lives [Table Text Block] | Depreciation is provided on PGE’s other classes of plant in service over their estimated average service lives, which are as follows (in years):
Generation, excluding thermal: |
Hydro | 97
Wind | 31
Transmission | 58
Distribution | 46
General | 13

X
- Definition Estimated average service lives [Table Text Block] + References No definition available. + Details
Name: | por_EstimatedAverageServiceLivesTableTextBlock
Namespace Prefix: | por_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- Definition Summary of Significant Accounting Policies [Abstract] + References No definition available. + Details
Name: | por_SummaryOfSignificantAccountingPoliciesAbstract
Namespace Prefix: | por_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration