Regulatory and Environmental Developments (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended	1 Months Ended	6 Months Ended	1 Months Ended
	Jun. 30, 2011	Apr. 30, 2011 Southern California Edison Company	Jun. 30, 2011 Homer City	Jun. 30, 2011 Greenhouse Gas Litigation Developments	Oct. 31, 2009 Kivalina case
Regulatory and environmental developments
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				5
Damages sought in Kivalina case					$ 400
Estimated capital costs for SO2 reduction, high end of the range			700
SO2 allowances allocated in CSAPR Phase I in second year (in tons)	25,797
SO2 allowances allocated in CSAPR Phase I in third year (in tons)	25,797
SO2 allowances allocated in CSAPR Phase I in current year (in tons)	112,951
SO2 allowances allocated in CSAPR Phase II (in tons)	11,068
Estimated capital costs for SO2 reduction, low end of the range			$ 600