XML 38 R24.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Jointly-owned Plant | 12 Months Ended
--- | ---
Dec. 31, 2017
Jointly-owned Plant [Abstract] |
Jointly-owned Plant [Text Block] | JOINTLY-OWNED PLANT As of December 31, 2017, PGE had the following investments in jointly-owned plant (dollars in millions):
| PGE Share |  | In-service Date |  | Plant In-service |  | Accumulated Depreciation* |  | Construction Work In Progress
Boardman | 90.00 | % |  | 1980 |  | $ | 515 |  |  | $ | 426 |  |  | $ | — |
Colstrip | 20.00 |  |  | 1986 |  | 546 |  |  | 351 |  |  | 5 |
Pelton/Round Butte | 66.67 |  |  | 1958 | / | 1964 |  | 251 |  |  | 68 |  |  | 7 |
Total |  |  |  |  |  |  | $ | 1,312 |  |  | $ | 845 |  |  | $ | 12 |
* | Excludes AROs and accumulated asset retirement removal costs.
Under the respective joint operating agreements for the three generating facilities, each participating owner is responsible for financing its share of construction, operating, and leasing costs. PGE’s proportionate share of direct operating and maintenance expenses of the facilities is included in the corresponding operating and maintenance expense categories in the consolidated statements of income.

X
- Definition Jointly-owned Plant [Abstract] + References No definition available. + Details
Name: | por_JointlyOwnedPlantAbstract
Namespace Prefix: | por_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Jointly-owned Plant [Text Block] + References No definition available. + Details
Name: | por_JointlyOwnedPlantTextBlock
Namespace Prefix: | por_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration