Other	3 Months Ended
Mar. 31, 2013
Other [Abstract]
Other Material Items [Text Block]	Other Jefferson County Public Utility District (JPUD). The Company completed the sale of its electric infrastructure assets located in Jefferson County and the transition of electrical services in the county to JPUD on March 31, 2013. The proceeds from the sale, which will be subject to a further true-up of certain related costs and reimbursement amounts 90 days from the date of the transaction exceed the transferred assets' net carrying value of $46.4 million resulting in a pre-tax gain of approximately $61.8 million. In its 2010 order on the subject, the Washington Commission stated that the Company must file an accounting and ratemaking petition with the Washington Commission to determine how this gain will be allocated between customers and shareholders. As a result, the gain was deferred and recorded as a regulatory liability until the Washington Commission determines the accounting and ratemaking treatment. The Company expects to complete this filing in the third quarter of 2013. For federal income tax purposes, the Company has elected to treat the transaction as an involuntary conversion under the Internal Revenue Code which allows tax deferral on the gain if PSE acquires qualified replacement property by December 31, 2015. Based on PSE's current construction program projection, it should have qualified replacement property; however, there can be no assurance that PSE will meet the requirement.

Other

Jefferson County Public Utility District (JPUD). The Company completed the sale of its electric infrastructure assets located in Jefferson County and the transition of electrical services in the county to JPUD on March 31, 2013. The proceeds from the sale, which will be subject to a further true-up of certain related costs and reimbursement amounts 90 days from the date of the transaction exceed the transferred assets' net carrying value of $46.4 million resulting in a pre-tax gain of approximately $61.8 million. In its 2010 order on the subject, the Washington Commission stated that the Company must file an accounting and ratemaking petition with the Washington Commission to determine how this gain will be allocated between customers and shareholders. As a result, the gain was deferred and recorded as a regulatory liability until the Washington Commission determines the accounting and ratemaking treatment. The Company expects to complete this filing in the third quarter of 2013.

For federal income tax purposes, the Company has elected to treat the transaction as an involuntary conversion under the Internal Revenue Code which allows tax deferral on the gain if PSE acquires qualified replacement property by December 31, 2015. Based on PSE's current construction program projection, it should have qualified replacement property; however, there can be no assurance that PSE will meet the requirement.