Regulation and Rates	3 Months Ended
Mar. 31, 2012
Regulation and Rates [Abstract]
Regulation and Rates	Regulation and Rates On January 6, 2012, PSE filed an electric transmission rate case with FERC as well as an increase in ancillary service charges. PSE requested a rate increase of $3.8 million with an effective date of April 1, 2012. On March 30, 2012, FERC issued an order setting for hearing PSE's formula transmission rate filing. PSE's proposed reclassification of facilities and formula rate for network and point-to-point service on the Washington Area Facilities have been suspended for five months until September 1, 2012. PSE's proposed formula rate decrease for service on the Colstrip and Southern Intertie lines have been accepted and placed into effect April 1, 2012 subject to refund if rates should be lower. The initial settlement conference is scheduled for May 2012. On February 29, 2012, PSE filed to increase the amount of the credit being passed back to customers in Schedule 95a, the Federal Incentive Tracker, by $2.4 million. PSE's proposed rate change seeks to include interest on the unamortized balance of United States Treasury Department grants (Treasury Grant) received on February 23, 2010, under Section 1603 of the American Recovery and Reinvestment Act of 2009. Inclusion of interest in rates became possible with the passage of the newly enacted National Defense Authorization Act for Fiscal Year 2012 (NDAA) which eliminated the requirement for utilities to normalize the Section 1603 Treasury Grant. PSE applied the interest beginning January 1, 2012. Washington Commission Staff seeks to include interest calculated from the date the Treasury Grant was received, February 2010. At the March 29, 2012 open meeting, the Washington Commission requested legal briefing of the issues. The Washington Commission recessed the matter until its May 24, 2012 open meeting. On May 7, 2012, the Washington Commission issued its order in PSE's consolidated electric and natural gas general rate case filed in June 2011, approving a general rate increase for electric customers of $63.3 million or 3.2% annually, and an increase in natural gas rates of $13.4 million or 1.3% annually. The rate increases for electric and natural gas customers will be effective May 14, 2012. In its order, the Washington Commission approved a weighted cost of capital of 7.8% and a capital structure that included 48.0% common equity with a return on equity of 9.80%.

Regulation and Rates

On January 6, 2012, PSE filed an electric transmission rate case with FERC as well as an increase in ancillary service charges. PSE requested a rate increase of $3.8 million with an effective date of April 1, 2012. On March 30, 2012, FERC issued an order setting for hearing PSE's formula transmission rate filing. PSE's proposed reclassification of facilities and formula rate for network and point-to-point service on the Washington Area Facilities have been suspended for five months until September 1, 2012. PSE's proposed formula rate decrease for service on the Colstrip and Southern Intertie lines have been accepted and placed into effect April 1, 2012 subject to refund if rates should be lower. The initial settlement conference is scheduled for May 2012.

On February 29, 2012, PSE filed to increase the amount of the credit being passed back to customers in Schedule 95a, the Federal Incentive Tracker, by $2.4 million. PSE's proposed rate change seeks to include interest on the unamortized balance of United States Treasury Department grants (Treasury Grant) received on February 23, 2010, under Section 1603 of the American Recovery and Reinvestment Act of 2009. Inclusion of interest in rates became possible with the passage of the newly enacted National Defense Authorization Act for Fiscal Year 2012 (NDAA) which eliminated the requirement for utilities to normalize the Section 1603 Treasury Grant. PSE applied the interest beginning January 1, 2012. Washington Commission Staff seeks to include interest calculated from the date the Treasury Grant was received, February 2010. At the March 29, 2012 open meeting, the Washington Commission requested legal briefing of the issues. The Washington Commission recessed the matter until its May 24, 2012 open meeting.

On May 7, 2012, the Washington Commission issued its order in PSE's consolidated electric and natural gas general rate case filed in June 2011, approving a general rate increase for electric customers of $63.3 million or 3.2% annually, and an increase in natural gas rates of $13.4 million or 1.3% annually. The rate increases for electric and natural gas customers will be effective May 14, 2012. In its order, the Washington Commission approved a weighted cost of capital of 7.8% and a capital structure that included 48.0% common equity with a return on equity of 9.80%.