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v2.4.0.6

Consolidated Statements of Comprehensive Income Consolidated Statement of Comprehensive Income Parentheticals (USD $) In Millions, unless otherwise specified | 12 Months Ended
--- | ---
Dec. 31, 2012 | Dec. 31, 2011 | Dec. 31, 2010
Net Taxes on change in compensation retirement benefits liability and amortization | $ 0 | $ 1 | $ 1

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- Definition Net Taxes on change in compensation retirement benefits liability and amortization + References No definition available. + Details
Name: | por_NetTaxesOnChangeInCompensationRetirementBenefitsLiabilityAndAmortization
Namespace Prefix: | por_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration