Regulatory Assets and Liabilities (Regulatory Balancing Accounts) (Details) (Southern California Edison, USD $) In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Regulatory balancing accounts | Energy resource recovery account
Regulatory Assets and Liabilities
Net liability	$ 1,570	$ 1,005
Regulatory balancing accounts | Four Corners memorandum account
Regulatory Assets and Liabilities
Net liability	6	145
Regulatory balancing accounts | New system generation balancing account
Regulatory Assets and Liabilities
Net liability	117	132
Refunds of excess revenue | Significant Components
Regulatory Assets and Liabilities
Net liability	(189)	(554)
Refunds of excess revenue | Public purpose programs and energy efficiency programs
Regulatory Assets and Liabilities
Net liability	(832)	(1,037)
Refunds of excess revenue | Base rate recovery balancing account
Regulatory Assets and Liabilities
Net liability	(243)	(247)
Refunds of excess revenue | Greenhouse gas auction revenue
Regulatory Assets and Liabilities
Net liability	(300)	(385)
Refunds of excess revenue | FERC formula rates and FERC balancing accounts
Regulatory Assets and Liabilities
Net liability	(89)	(59)
Refunds of excess revenue | FERC energy settlements
Regulatory Assets and Liabilities
Net liability	(195)	0
Refunds of excess revenue | Other
Regulatory Assets and Liabilities
Net liability	$ (223)	$ (108)