Environmental Developments	9 Months Ended
Sep. 30, 2012
Environmental Developments [Abstract]
Environmental Developments	Environmental Developments Cross-State Air Pollution Rule In August 2012, the U.S. Court of Appeals for the District of Columbia Circuit vacated the US EPA's Cross-State Air Pollution Rule ("CSAPR") and directed the US EPA to continue administering the Clean Air Interstate Rule pending the promulgation of a valid replacement. In October 2012, the US EPA filed a petition seeking to have the decision reviewed by the full District of Columbia Circuit. Hazardous Air Pollutant Regulations In December 2011, the US EPA announced the Mercury and Air Toxics Standards rule, limiting emissions of hazardous air pollutants from coal- and oil-fired electrical generating units. The rule was published in the Federal Register on February 16, 2012, and became effective on April 16, 2012. A number of parties have filed notices of appeal challenging the rule. Greenhouse Gas Regulation In March 2012, the US EPA announced proposed carbon dioxide emissions limits for new power plants. The status of the US EPA's efforts to develop greenhouse gas emissions performance standards for existing plants is unknown. In June 2012, the U.S. Court of Appeals for the D.C. Circuit dismissed the challenge by industry groups and some states to the Prevention of Significant Deterioration and Title V Greenhouse Gas Tailoring Rule, known as the "GHG tailoring rule." In August 2012, states and industry groups challenging the rule filed a petition seeking to have the decision reviewed by the full District of Columbia Circuit. In July 2012, the US EPA published a final rule maintaining the CO₂equivalent emissions thresholds (for purposes of PSD and Title V permitting) originally established in the GHG tailoring rule. Greenhouse Gas Litigation In March 2012, the federal district court in Mississippi dismissed, in its entirety, the purported class action complaint filed by private citizens in May 2011, naming a large number of defendants, including SCE, EME and other Edison International subsidiaries, for damages allegedly arising from Hurricane Katrina. In April 2012, the plaintiffs filed an appeal with the Fifth Circuit Court of Appeals. Plaintiffs allege that the defendants' activities resulted in emissions of substantial quantities of greenhouse gases that have contributed to climate change and sea level rise, which in turn are alleged to have increased the destructive force of Hurricane Katrina. The lawsuit alleges causes of action for negligence, public and private nuisance, and trespass, and seeks unspecified compensatory and punitive damages. The claims in this lawsuit are nearly identical to a subset of the claims that were raised against many of the same defendants in a previous lawsuit that was filed in, and dismissed by, the same federal district court where the current case has been filed. In September 2012, a three-judge panel of the U.S Court of Appeals for the Ninth Circuit affirmed the dismissal of a case brought against Edison International and other defendants, by the Alaskan Native Village of Kivalina. In October 2012, the plaintiffs requested a rehearing by a larger panel of Ninth Circuit judges.

Environmental Developments

Cross-State Air Pollution Rule

In August 2012, the U.S. Court of Appeals for the District of Columbia Circuit vacated the US EPA's Cross-State Air Pollution Rule ("CSAPR") and directed the US EPA to continue administering the Clean Air Interstate Rule pending the promulgation of a valid replacement. In October 2012, the US EPA filed a petition seeking to have the decision reviewed by the full District of Columbia Circuit.

Hazardous Air Pollutant Regulations

In December 2011, the US EPA announced the Mercury and Air Toxics Standards rule, limiting emissions of hazardous air pollutants from coal- and oil-fired electrical generating units. The rule was published in the Federal Register on February 16, 2012, and became effective on April 16, 2012. A number of parties have filed notices of appeal challenging the rule.

Greenhouse Gas Regulation

In March 2012, the US EPA announced proposed carbon dioxide emissions limits for new power plants. The status of the US EPA's efforts to develop greenhouse gas emissions performance standards for existing plants is unknown.

In June 2012, the U.S. Court of Appeals for the D.C. Circuit dismissed the challenge by industry groups and some states to the Prevention of Significant Deterioration and Title V Greenhouse Gas Tailoring Rule, known as the "GHG tailoring rule." In August 2012, states and industry groups challenging the rule filed a petition seeking to have the decision reviewed by the full District of Columbia Circuit.

In July 2012, the US EPA published a final rule maintaining the CO₂equivalent emissions thresholds (for purposes of PSD and Title V permitting) originally established in the GHG tailoring rule.

Greenhouse Gas Litigation

In March 2012, the federal district court in Mississippi dismissed, in its entirety, the purported class action complaint filed by private citizens in May 2011, naming a large number of defendants, including SCE, EME and other Edison International subsidiaries, for damages allegedly arising from Hurricane Katrina. In April 2012, the plaintiffs filed an appeal with the Fifth Circuit Court of Appeals. Plaintiffs allege that the defendants' activities resulted in emissions of substantial quantities of greenhouse gases that have contributed to climate change and sea level rise, which in turn are alleged to have increased the destructive force of Hurricane Katrina. The lawsuit alleges causes of action for negligence, public and private nuisance, and trespass, and seeks unspecified compensatory and punitive damages. The claims in this lawsuit are nearly identical to a subset of the claims that were raised against many of the same defendants in a previous lawsuit that was filed in, and dismissed by, the same federal district court where the current case has been filed.

In September 2012, a three-judge panel of the U.S Court of Appeals for the Ninth Circuit affirmed the dismissal of a case brought against Edison International and other defendants, by the Alaskan Native Village of Kivalina. In October 2012, the plaintiffs requested a rehearing by a larger panel of Ninth Circuit judges.