XML 80 R67.htm IDEA: XBRL DOCUMENT
v3.6.0.2

Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions | Dec. 31, 2016 | Dec. 31, 2015
--- | --- | ---
Regulatory Assets and Liabilities Disclosure [Abstract] |  |
Regulatory Assets Earning a Return, Other Category | $ 44 | $ 29
Regulatory Assets Earning a Return | 44 |
Regulatory Assets Earning a Rate of Return at the Cost of Capital | $ 19 |
Authorized Cost of Capital | 7.56% |
Regulatory Assets Earning a Rate of Return by Inclusion in Rate Base | $ 22 |
Regulatory Assets Earning a Rate of Return at the Approved Rate | $ 3 |
Approved Rate for Deferred Account Under Amortization, Low End of Range | 1.47% |
Approved Rate for Deferred Accounts under Amortization, High End of Range | 2.20% |

X
- Definition Low end of the range of approved rates of return for amortizing deferred accounts (regulatory assets). + References No definition available. + Details
Name: | por_ApprovedRateForDeferredAccountUnderAmortizationLowEndOfRange
Namespace Prefix: | por_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition High end of the range of approved rates of return for amortizing deferred accounts (regulatory assets). + References No definition available. + Details
Name: | por_ApprovedRateForDeferredAccountsUnderAmortizationHighEndOfRange
Namespace Prefix: | por_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Authorized cost of capital rate. + References No definition available. + Details
Name: | por_AuthorizedCostOfCapital
Namespace Prefix: | por_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Regulatory assets earning a rate of return at the approved rate. + References No definition available. + Details
Name: | por_RegulatoryAssetsEarningRateOfReturnAtApprovedRate
Namespace Prefix: | por_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Regulatory assets earning a rate of return at the cost of capital. + References No definition available. + Details
Name: | por_RegulatoryAssetsEarningRateOfReturnAtCostOfCapital
Namespace Prefix: | por_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Regulatory assets earning a rate of return by inclusion in rate base. + References No definition available. + Details
Name: | por_RegulatoryAssetsEarningRateOfReturnByInclusionInRateBase
Namespace Prefix: | por_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Regulatory assets earning a rate of return. + References No definition available. + Details
Name: | por_RegulatoryAssetsEarningReturn
Namespace Prefix: | por_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Regulatory assets in 'other' category earning a rate of return. + References No definition available. + Details
Name: | por_RegulatoryAssetsEarningReturnOtherCategory
Namespace Prefix: | por_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

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