Litigation	6 Months Ended
Jun. 30, 2014
Litigation Disclosure [Abstract]
Litigation	Litigation Residential Exchange The Northwest Power Act, through the Residential Exchange Program (REP), provides access to the benefits of low-cost federal power for residential and small farm customers of regional utilities, including PSE. The program is administered by the Bonneville Power Administration (BPA). Pursuant to agreements (including settlement agreements) between the BPA and PSE, the BPA has provided payments of REP benefits to PSE, which PSE has passed through to its residential and small farm customers in the form of electricity bill credits. In 2007, the United States Court of Appeals for the Ninth Circuit (Ninth Circuit) ruled that REP agreements of the BPA with PSE and a number of other investor-owned utilities were inconsistent with the Northwest Power Act. Since that time, those investor-owned utilities, including PSE, the BPA and other parties have been involved in ongoing litigation at the Ninth Circuit relating to the amount of REP benefits paid to utilities, including PSE, for the fiscal year 2002 through fiscal year 2011 period and the amount of REP benefits to be paid going forward. In July 2011, the BPA, PSE and a number of other parties entered into a settlement agreement (2012 REP Settlement) that by its terms, if upheld in its entirety, would resolve the disputes between BPA and PSE regarding REP benefits paid for fiscal years 2002-2011 and determine REP benefits for fiscal years 2012-2028. In October 2011, certain other parties challenged BPA decisions with regard to its entering into the 2012 REP Settlement agreement. On October 28, 2013, the Ninth Circuit issued an order dismissing this challenge to this settlement. In light of the disposition of this challenge, the stay of the other pending Ninth Circuit litigation regarding REP benefits was lifted in January 2014. In the order lifting the stay, petitioners (unless they move to voluntarily dismiss their petitions) and intervenors (unless they move to voluntarily withdraw) were directed to file a statement explaining which issues, if any, remain pending. Subsequent to the order lifting the stay, in February 2014, one group of petitioners in the other pending Ninth Circuit litigation moved to dismiss its petition and its motion was granted. Two of the remaining petitioners may seek dismissal of their petitions, but other remaining petitioners are pursuing certain claims relating to the amount of REP benefits paid to utilities, including PSE, for the period of fiscal years 2002 through 2011. PSE is unable to determine what impact these proceedings may have on PSE. However, the Company believes it is unlikely that any unfavorable outcome would have a material adverse effect on PSE because REP benefits received by PSE are passed through directly to REP customers. With the Ninth Circuit’s decision affirming the 2012 REP Settlement, PSE will receive $62.9 million in REP payments owed under a 2008 agreement, which are in addition to scheduled monthly REP benefits received from BPA under the 2012 REP Settlement. These payments will be given back to PSE's residential and small farm customers through a higher residential exchange credit during the period June 1, 2014 to May 31, 2015. Colstrip PSE has a 50% ownership interest in Colstrip Units 1 and 2, and a 25% interest in Colstrip Units 3 and 4. On March 6, 2013, Sierra Club and Montana Environmental Information Center (MEIC) filed a Clean Air Act citizen suit against all Colstrip owners (including PSE) alleging numerous claims for relief, most which relate to alleged prevention of significant deterioration (PSD) violations. One claim relates to the alleged failure to update the Title V permit to reflect the major modifications alleged in the first thirty-six claims, another claim alleges that the previous Title V compliance certifications have been incomplete because they did not address the alleged major modifications, and the last claim alleges opacity violations since 2007. The lawsuit was filed in U.S. District of Montana, Billings Division, requesting injunctive relief and civil penalties, including a request that the owners remediate environmental damage and that $100,000 of the civil penalties be used for beneficial mitigation projects. This lawsuit followed various Notices of Intent to Sue sent to Colstrip owners (including PSE) from the Sierra Club and the MEIC between July and December 2012. Discovery in the case has begun, and the case has been bifurcated into separate liability and remedy trials. The liability trial is currently set for June 2015, and a date for the remedy trial has yet to be determined. PSE is litigating the allegations set forth in the notices and cannot at this time predict the outcome of this matter. Other Proceedings The Company is also involved in litigation relating to claims arising out of its operations in the normal course of business. The Company has recorded reserves of $1.29 million and $1.38 million relating to these claims as of June 30, 2014 and December 31, 2013, respectively.

Litigation

Residential Exchange

The Northwest Power Act, through the Residential Exchange Program (REP), provides access to the benefits of low-cost federal power for residential and small farm customers of regional utilities, including PSE. The program is administered by the Bonneville Power Administration (BPA). Pursuant to agreements (including settlement agreements) between the BPA and PSE, the BPA has provided payments of REP benefits to PSE, which PSE has passed through to its residential and small farm customers in the form of electricity bill credits.

In 2007, the United States Court of Appeals for the Ninth Circuit (Ninth Circuit) ruled that REP agreements of the BPA with PSE and a number of other investor-owned utilities were inconsistent with the Northwest Power Act. Since that time, those investor-owned utilities, including PSE, the BPA and other parties have been involved in ongoing litigation at the Ninth Circuit relating to the amount of REP benefits paid to utilities, including PSE, for the fiscal year 2002 through fiscal year 2011 period and the amount of REP benefits to be paid going forward.

In July 2011, the BPA, PSE and a number of other parties entered into a settlement agreement (2012 REP Settlement) that by its terms, if upheld in its entirety, would resolve the disputes between BPA and PSE regarding REP benefits paid for fiscal years 2002-2011 and determine REP benefits for fiscal years 2012-2028. In October 2011, certain other parties challenged BPA decisions with regard to its entering into the 2012 REP Settlement agreement. On October 28, 2013, the Ninth Circuit issued an order dismissing this challenge to this settlement. In light of the disposition of this challenge, the stay of the other pending Ninth Circuit litigation regarding REP benefits was lifted in January 2014. In the order lifting the stay, petitioners (unless they move to voluntarily dismiss their petitions) and intervenors (unless they move to voluntarily withdraw) were directed to file a statement explaining which issues, if any, remain pending. Subsequent to the order lifting the stay, in February 2014, one group of petitioners in the other pending Ninth Circuit litigation moved to dismiss its petition and its motion was granted. Two of the remaining petitioners may seek dismissal of their petitions, but other remaining petitioners are pursuing certain claims relating to the amount of REP benefits paid to utilities, including PSE, for the period of fiscal years 2002 through 2011. PSE is unable to determine what impact these proceedings may have on PSE. However, the Company believes it is unlikely that any unfavorable outcome would have a material adverse effect on PSE because REP benefits received by PSE are passed through directly to REP customers.

With the Ninth Circuit’s decision affirming the 2012 REP Settlement, PSE will receive $62.9 million in REP payments owed under a 2008 agreement, which are in addition to scheduled monthly REP benefits received from BPA under the 2012 REP Settlement. These payments will be given back to PSE's residential and small farm customers through a higher residential exchange credit during the period June 1, 2014 to May 31, 2015.

Colstrip

PSE has a 50% ownership interest in Colstrip Units 1 and 2, and a 25% interest in Colstrip Units 3 and 4. On March 6, 2013, Sierra Club and Montana Environmental Information Center (MEIC) filed a Clean Air Act citizen suit against all Colstrip owners (including PSE) alleging numerous claims for relief, most which relate to alleged prevention of significant deterioration (PSD) violations. One claim relates to the alleged failure to update the Title V permit to reflect the major modifications alleged in the first thirty-six claims, another claim alleges that the previous Title V compliance certifications have been incomplete because they did not address the alleged major modifications, and the last claim alleges opacity violations since 2007. The lawsuit was filed in U.S. District of Montana, Billings Division, requesting injunctive relief and civil penalties, including a request that the owners remediate environmental damage and that $100,000 of the civil penalties be used for beneficial mitigation projects. This lawsuit followed various Notices of Intent to Sue sent to Colstrip owners (including PSE) from the Sierra Club and the MEIC between July and December 2012. Discovery in the case has begun, and the case has been bifurcated into separate liability and remedy trials. The liability trial is currently set for June 2015, and a date for the remedy trial has yet to be determined. PSE is litigating the allegations set forth in the notices and cannot at this time predict the outcome of this matter.

Other Proceedings

The Company is also involved in litigation relating to claims arising out of its operations in the normal course of business. The Company has recorded reserves of $1.29 million and $1.38 million relating to these claims as of June 30, 2014 and December 31, 2013, respectively.