Debt and Credit Agreements	9 Months Ended
Sep. 30, 2012
Debt Disclosure [Abstract]
Debt and Credit Agreements	Debt and Credit Agreements Project Financings Broken Bow and Crofton Bluffs Effective March 30, 2012, EME, through its subsidiaries, Broken Bow Wind, LLC and Crofton Bluffs Wind, LLC, completed two nonrecourse financings of its interests in the Broken Bow and Crofton Bluffs wind projects. The financings included construction loans totaling $79 million that are required to be converted to 15-year amortizing term loans by March 31, 2013, subject to meeting specified conditions, $13 million letter of credit facilities and $6 million working capital facilities. Interest under the construction and term loans will accrue at London Interbank Offered Rate (LIBOR) plus 2.875%, with the term loan rate increasing 0.125% after the third, sixth, ninth, and twelfth years. As of September 30, 2012, $21 million and $6 million were outstanding under the construction loans included in short-term debt on EME's consolidated balance sheet, and letters of credit facilities, respectively. Tapestry Wind In December 2011, EME through its subsidiary, Tapestry Wind, LLC, completed a nonrecourse financing of its interests in the Taloga, Buffalo Bear and Pinnacle wind projects. A total of $97 million of cash proceeds received from the $214 million 10-year partially amortizing term loan was deposited into an escrow account as of December 31, 2011. On February 22, 2012, a neighbor of the Pinnacle project, filed a formal complaint with the West Virginia Public Service Commission regarding, among other things, noise emissions and shadow flicker and requested that the Commission order the project to shut down at night due to alleged noise emissions. This complaint was dismissed on June 1, 2012. On June 27, 2012 and on July 3, 2012, nearly identical complaints were filed with the West Virginia Public Service Commission by two other neighbors and were subsequently dismissed. In addition, on June 25, 2012, each of the three neighbors filed separate civil complaints in the Circuit Court of Mineral County, West Virginia against Pinnacle Wind, LLC, EME, Edison Mission Operations and Maintenance, Inc., and other non-affiliated defendants. The civil complaints allege, among other things, that the noise emissions and shadow flicker from the Pinnacle wind farm constitute a nuisance and seek compensatory damages, punitive damages and other equitable relief. The complaints have been dismissed without prejudice. The release of the loan proceeds in escrow is subject to final resolution of the complaints or further due diligence from the lenders. Big Sky Turbine Financing In October 2009, EME, through its subsidiary, Big Sky Wind, LLC (Big Sky), entered into turbine financing arrangements with the turbine manufacturer, totaling approximately $206 million for wind turbine purchase obligations related to the 240 MW Big Sky wind project. The loan has a five-year final maturity, however, specific events, including project performance, may trigger earlier repayment which could occur as early as February 2013. Big Sky is currently involved in a dispute with the lender/turbine manufacturer around whether certain latent defects existing in the turbine equipment would preclude the early repayment provisions. The loan is secured by a leasehold mortgage on the project's real property assets, a pledge of all other collateral of the Big Sky wind project, as well as a cash reserve account into which one-third of distributable cash flow, if any, of the Big Sky wind project is to be deposited on a monthly basis. The loan is also secured by pledges of Big Sky's direct and indirect ownership interests in the project but is non-recourse to EME. Big Sky will need to arrange alternative financing, if available, to repay the loan at maturity or reach agreement with the lender to extend the maturity date of the loan as EME does not plan to make an investment in the project and is under no obligation to do so. If these efforts are unsuccessful, the lender may foreclose on the project resulting in a write off of the entire investment in the project. At September 30, 2012, EME's net investment in the Big Sky wind project was $130 million. Long-Term Debt In March 2012, SCE issued $400 million of 4.05% first and refunding mortgage bonds due in 2042. The proceeds from these bonds were used to repay commercial paper borrowings and to fund SCE's capital program. Credit Agreements and Short-Term Debt During the second quarter of 2012, SCE replaced its credit facilities with a $2.75 billion five-year revolving credit facility that matures in May 2017. The credit facility is generally used to support commercial paper and letters of credit issued for procurement-related collateral requirements, balancing account undercollections and for general corporate purposes, including working capital requirements to support operations and capital expenditures. At September 30, 2012, SCE's outstanding commercial paper supported by the credit facility was $380 million at a weighted-average interest rate of 0.43%. At September 30, 2012, letters of credit issued under SCE's credit facility aggregated $196 million and are scheduled to expire in twelve months or less. At December 31, 2011, the outstanding commercial paper was $419 million at a weighted-average interest rate of 0.44%. In February 2012, EME terminated its $564 million revolving credit facility. Midwest Generation's $500 million credit facility expired in June 2012 as per its terms. In the first quarter of 2012, EME completed a $100 million letter of credit facility for EME's general corporate needs and for its projects, which expires on June 30, 2014. Letters of credit issued under this facility are secured by cash collateral at least equal to the issued amount. During the second quarter of 2012, Edison International (parent) replaced its credit facility with a $1.25 billion five-year revolving credit facility that matures in May 2017. Borrowings under this credit facility are used for general corporate purposes. At September 30, 2012, Edison International (parent) outstanding short-term debt supported by this credit facility was $28 million at a weighted-average interest rate of 1.52%. At December 31, 2011, the outstanding short-term debt was $10 million at a weighted-average interest rate of 0.66%. Letters of Credit At September 30, 2012, letters of credit under EME's and its subsidiaries' credit facilities aggregated $154 million. EME had $51 million of cash collateral supporting its letters of credit which were scheduled to expire as follows: $48 million in 2013 and $3 million in 2014. In addition, EME's subsidiaries' credit facilities aggregated $103 million and were scheduled to expire as follows: $2 million in 2012, $49 million in 2013, $21 million in 2017, $18 million in 2018 and $13 million in 2021. Standby letters of credit include $30 million issued in connection with the power purchase agreement with SCE under the Walnut Creek credit facility. Certain letters of credit are subject to automatic annual renewal provisions.

Debt and Credit Agreements

Project Financings

Broken Bow and Crofton Bluffs

Effective March 30, 2012, EME, through its subsidiaries, Broken Bow Wind, LLC and Crofton Bluffs Wind, LLC, completed two nonrecourse financings of its interests in the Broken Bow and Crofton Bluffs wind projects. The financings included construction loans totaling $79 million that are required to be converted to 15-year amortizing term loans by March 31, 2013, subject to meeting specified conditions, $13 million letter of credit facilities and $6 million working capital facilities. Interest under the construction and term loans will accrue at London Interbank Offered Rate (LIBOR) plus 2.875%, with the term loan rate increasing 0.125% after the third, sixth, ninth, and twelfth years. As of September 30, 2012, $21 million and $6 million were outstanding under the construction loans included in short-term debt on EME's consolidated balance sheet, and letters of credit facilities, respectively.

Tapestry Wind

In December 2011, EME through its subsidiary, Tapestry Wind, LLC, completed a nonrecourse financing of its interests in the Taloga, Buffalo Bear and Pinnacle wind projects. A total of $97 million of cash proceeds received from the $214 million 10-year partially amortizing term loan was deposited into an escrow account as of December 31, 2011. On February 22, 2012, a neighbor of the Pinnacle project, filed a formal complaint with the West Virginia Public Service Commission regarding, among other things, noise emissions and shadow flicker and requested that the Commission order the project to shut down at night due to alleged noise emissions. This complaint was dismissed on June 1, 2012. On June 27, 2012 and on July 3, 2012, nearly identical complaints were filed with the West Virginia Public Service Commission by two other neighbors and were subsequently dismissed. In addition, on June 25, 2012, each of the three neighbors filed separate civil complaints in the Circuit Court of Mineral County, West Virginia against Pinnacle Wind, LLC, EME, Edison Mission Operations and Maintenance, Inc., and other non-affiliated defendants. The civil complaints allege, among other things, that the noise emissions and shadow flicker from the Pinnacle wind farm constitute a nuisance and seek compensatory damages, punitive damages and other equitable relief. The complaints have been dismissed without prejudice. The release of the loan proceeds in escrow is subject to final resolution of the complaints or further due diligence from the lenders.

Big Sky Turbine Financing

In October 2009, EME, through its subsidiary, Big Sky Wind, LLC (Big Sky), entered into turbine financing arrangements with the turbine manufacturer, totaling approximately $206 million for wind turbine purchase obligations related to the 240 MW Big Sky wind project. The loan has a five-year final maturity, however, specific events, including project performance, may trigger earlier repayment which could occur as early as February 2013. Big Sky is currently involved in a dispute with the lender/turbine manufacturer around whether certain latent defects existing in the turbine equipment would preclude the early repayment provisions. The loan is secured by a leasehold mortgage on the project's real property assets, a pledge of all other collateral of the Big Sky wind project, as well as a cash reserve account into which one-third of distributable cash flow, if any, of the Big Sky wind project is to be deposited on a monthly basis. The loan is also secured by pledges of Big Sky's direct and indirect ownership interests in the project but is non-recourse to EME.

Big Sky will need to arrange alternative financing, if available, to repay the loan at maturity or reach agreement with the lender to extend the maturity date of the loan as EME does not plan to make an investment in the project and is under no obligation to do so. If these efforts are unsuccessful, the lender may foreclose on the project resulting in a write off of the entire investment in the project. At September 30, 2012, EME's net investment in the Big Sky wind project was $130 million.

Long-Term Debt

In March 2012, SCE issued $400 million of 4.05% first and refunding mortgage bonds due in 2042. The proceeds from these bonds were used to repay commercial paper borrowings and to fund SCE's capital program.

Credit Agreements and Short-Term Debt

During the second quarter of 2012, SCE replaced its credit facilities with a $2.75 billion five-year revolving credit facility that matures in May 2017. The credit facility is generally used to support commercial paper and letters of credit issued for procurement-related collateral requirements, balancing account undercollections and for general corporate purposes, including working capital requirements to support operations and capital expenditures. At September 30, 2012, SCE's outstanding commercial paper supported by the credit facility was $380 million at a weighted-average interest rate of 0.43%. At September 30, 2012, letters of credit issued under SCE's credit facility aggregated $196 million and are scheduled to expire in twelve months or less. At December 31, 2011, the outstanding commercial paper was $419 million at a weighted-average interest rate of 0.44%.

In February 2012, EME terminated its $564 million revolving credit facility. Midwest Generation's $500 million credit facility expired in June 2012 as per its terms. In the first quarter of 2012, EME completed a $100 million letter of credit facility for EME's general corporate needs and for its projects, which expires on June 30, 2014. Letters of credit issued under this facility are secured by cash collateral at least equal to the issued amount.

During the second quarter of 2012, Edison International (parent) replaced its credit facility with a $1.25 billion five-year revolving credit facility that matures in May 2017. Borrowings under this credit facility are used for general corporate purposes. At September 30, 2012, Edison International (parent) outstanding short-term debt supported by this credit facility was $28 million at a weighted-average interest rate of 1.52%. At December 31, 2011, the outstanding short-term debt was $10 million at a weighted-average interest rate of 0.66%.

Letters of Credit

At September 30, 2012, letters of credit under EME's and its subsidiaries' credit facilities aggregated $154 million. EME had $51 million of cash collateral supporting its letters of credit which were scheduled to expire as follows: $48 million in 2013 and $3 million in 2014. In addition, EME's subsidiaries' credit facilities aggregated $103 million and were scheduled to expire as follows: $2 million in 2012, $49 million in 2013, $21 million in 2017, $18 million in 2018 and $13 million in 2021. Standby letters of credit include $30 million issued in connection with the power purchase agreement with SCE under the Walnut Creek credit facility. Certain letters of credit are subject to automatic annual renewal provisions.