Regulatory Assets and Liabilities Regulatory Assets and Liabilities (Policies)	12 Months Ended
Dec. 31, 2011
Regulatory Assets and Liabilities [Abstract]
Description of Impairment to Carrying Amount of Regulatory Assets	During the fourth quarter of 2011, PGE received an order from the OPUC on its Annual Update Tariff for 2012 net variable power costs (NVPC). Pursuant to the order, the OPUC reduced the Company’s 2012 NVPC forecast by approximately $3 million, which is reflected as a reduction to the regulatory asset for price risk management as of December 31, 2011.
Refund Period Not Yet Determined for REgulatory Liabilities, PCAM and Pollution Control Tax Credits	Refund period not yet determined
Remaining Recovery Period of Regulatory Asset, Pension and Postretirement Plans, For Which No Return on Investment During Recovery is Provided	Recovery expected over the average service life of employees
Remaining Refund Period of Regulatory Liabilities, Asset Removal Costs and Retirement Obligations	Recovery expected over the estimated lives of the assets

Regulatory Assets and Liabilities Regulatory Assets and Liabilities (Policies)

12 Months Ended

Dec. 31, 2011

Regulatory Assets and Liabilities [Abstract]

Description of Impairment to Carrying Amount of Regulatory Assets

During the fourth quarter of 2011, PGE received an order from the OPUC on its Annual Update Tariff for 2012 net variable power costs (NVPC). Pursuant to the order, the OPUC reduced the Company’s 2012 NVPC forecast by approximately $3 million, which is reflected as a reduction to the regulatory asset for price risk management as of December 31, 2011.

Refund Period Not Yet Determined for REgulatory Liabilities, PCAM and Pollution Control Tax Credits

Refund period not yet determined

Remaining Recovery Period of Regulatory Asset, Pension and Postretirement Plans, For Which No Return on Investment During Recovery is Provided

Recovery expected over the average service life of employees

Remaining Refund Period of Regulatory Liabilities, Asset Removal Costs and Retirement Obligations

Recovery expected over the estimated lives of the assets