Environmental Developments (Textual) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
Dec. 31, 2011 Southern California Edison	Apr. 30, 2011 Southern California Edison	Jun. 30, 2011 Greenhouse Gas Litigation Developments companies	Dec. 31, 2012 Kivalina Litigation
Environmental Exit Cost [Line Items]
Electricity requirements required to be purchased as per the law enacted by legislature (as a percent)		33.00%
Number of power companies against whom public nuisance claims are dismissed (companies)			5
Damages sought in Kivalina case	$ 98			$ 400

The value (monetary amount) of the award the plaintiff seeks in the legal matter.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 7: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

+ Details