Debt and Credit Agreements (Additional Information) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014 MW	Dec. 31, 2013	Mar. 31, 2014	Jan. 31, 2015
Short-term Debt [Line Items]
Outstanding borrowings	$ 619,000,000	$ 34,000,000
Short-term debt	1,291,000,000	209,000,000
Weighted average interest rate (as a percent)	0.45%	0.55%
Non-recourse Solar Rooftop Project Equity Investment Financing
Short-term Debt [Line Items]
Debt Instrument, Face Amount	80,000,000
Non-recourse Solar Rooftop Project Investment Financing
Short-term Debt [Line Items]
Weighted average interest rate (as a percent)	2.67%
Debt Instrument, Face Amount	31,600,000
Power generating capacity (in megawatts)	35
Debt Instrument, Term	7 years
Outstanding balance	5,100,000
Revolving credit facility maturing in July 2018
Short-term Debt [Line Items]
Commitment	1,250,000,000
Outstanding borrowings	619,000,000
Outstanding letters of credit	0
Amount available	631,000,000
Southern California Edison
Short-term Debt [Line Items]
Short-term debt	667,000,000	175,000,000
Southern California Edison | Revolving credit facility maturing in July 2018
Short-term Debt [Line Items]
Commitment	2,750,000,000
Outstanding borrowings	367,000,000
Outstanding letters of credit	(109,000,000)
Amount available	2,274,000,000
Southern California Edison | First and refunding mortgage bonds:
Short-term Debt [Line Items]
Debt Instrument, Face Amount			300,000,000
Southern California Edison | Amortizing First and Refunding Mortgage Bonds Due in 2022 | Subsequent Event
Short-term Debt [Line Items]
Debt Instrument, Face Amount				550,000,000
Interest rate on debt (as a percent)				1.845%
Southern California Edison | First and Refunding Mortgage Bonds Due in 2022 | Subsequent Event
Short-term Debt [Line Items]
Debt Instrument, Face Amount				325,000,000
Interest rate on debt (as a percent)				2.40%
Southern California Edison | First and Refunding Mortgage Bonds Due in 2045 | Subsequent Event
Short-term Debt [Line Items]
Debt Instrument, Face Amount				425,000,000
Interest rate on debt (as a percent)				3.60%
Commercial paper | Southern California Edison | Revolving credit facility maturing in July 2018
Short-term Debt [Line Items]
Short-term debt		$ 175,000,000
Weighted average interest rate (as a percent)	0.40%	0.24%
Letters of credit | Southern California Edison | Revolving credit facility maturing in July 2018
Short-term Debt [Line Items]
Letters of credit expiration period	12 months