Permanent Retirement of San Onofre (Details) (USD $)	3 Months Ended		9 Months Ended			9 Months Ended				1 Months Ended	3 Months Ended	4 Months Ended	9 Months Ended			9 Months Ended			3 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012	Dec. 31, 2012	Sep. 30, 2013 San Onofre (nuclear)	Jun. 30, 2013 San Onofre (nuclear)	Sep. 30, 2013 Southern California Edison	Dec. 31, 2012 Southern California Edison	Jun. 30, 2013 Southern California Edison San Onofre (nuclear)	Jun. 30, 2013 Southern California Edison San Onofre (nuclear) positions	Sep. 30, 2013 Southern California Edison San Onofre (nuclear) invoices	Sep. 30, 2013 Southern California Edison San Onofre (nuclear) positions invoices	May 31, 2013 Southern California Edison San Onofre (nuclear)	Sep. 30, 2013 Mitsubishi Heavy Industries Ltd [Member] San Onofre (nuclear)	Sep. 30, 2013 Replacement Steam Generators Southern California Edison San Onofre (nuclear)	Sep. 30, 2013 Supporting Ongoing Activities at the Site Southern California Edison San Onofre (nuclear)	Sep. 30, 2013 Employee severance Southern California Edison San Onofre (nuclear)	Jun. 30, 2013 Decommissioning Plan Southern California Edison San Onofre (nuclear) positions	Sep. 30, 2013 Property, plant and equipment Southern California Edison San Onofre (nuclear)	Sep. 30, 2013 Estimated losses on disposal of nuclear fuel inventory Southern California Edison San Onofre (nuclear)	Sep. 30, 2013 Refunds of excess revenue Southern California Edison San Onofre (nuclear)
Regulatory Assets [Line Items]
Cumulative amount of revenue collected since January 1, 2012												$ 1,100,000,000	$ 1,100,000,000
Cost of service										56,000,000			(129,000,000)
Decommissioning Nuclear Facilities Net Investment														2,100,000,000
Authorized expenditures by authoritative body												525,000,000	525,000,000
Authorized expenditures by authoritative body, after adjustments for inflation												665,000,000	665,000,000
Jointly Owned Utility Plant, Proportionate Ownership Share												78.21%	78.21%
Authorized expenditures by authoritative body, spent to date													602,000,000
Authorized expenditures by authoritative body, market costs incurred												191,000,000	680,000,000
Authorized expenditures by authoritative body, Planned Outage Costs													65,000,000
Public Utilities, Incremental Inspection and Repair Costs													115,000,000
Public Utilities, Incremental Inspection and Repair Costs, Payments from Third Party													36,000,000
Amount of assets reclassified to a regulatory asset														1,521,000,000
Regulatory assets	8,015,000,000		8,015,000,000		6,422,000,000			8,015,000,000	6,422,000,000								404,000,000
Asset impairment and other	0	(66,000,000)	575,000,000	(65,000,000)							575,000,000
Asset impairment net of tax											365,000,000
San Onofre expected number of positions to be eliminated											960		960						175
Disposal Group, Including Discontinued Operation, Accrued Liabilities																		56,000,000
Net regulatory asset												1,450,000,000	1,450,000,000							1,540,000,000	33,000,000	(129,000,000)
Warranty Period																20 years
Maximum liability for purchase agreement for damages															138,000,000
Notice of intent to sue, notice time period						90 days
Number of Invoices for Reimbursement												7	7
Gain Contingency, Invoiced Amount for Reimbursement												149,000,000	149,000,000
Gain Contingency, Invoiced Amount Paid for Reimbursement													45,000,000
Notice Of Claim Amount							$ 390,000,000			$ 306,000,000	$ 306,000,000
Outage Policy Benefit Reduction Percentage			90.00%