XML 37 R31.htm IDEA: XBRL DOCUMENT v2.3.0.11

Basis of Presentation (Details)	Jun. 30, 2011
Basis of Presentation [Abstract]
NumberofRetailCustomers	824,526

X

- Definition

Basis of Presentation [Abstract]

+ Details

Name:	por_BasisOfPresentationAbstract
Namespace Prefix:	por
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

Includes residential, commercial and industrial.

+ Details

Name:	por_NumberOfRetailCustomers
Namespace Prefix:	por
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant