Regulatory Assets and Liabilities (Schedule of Net Regulatory Balancing Accounts) (Details) - Southern California Edison - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
Regulatory balancing accounts | Energy resource recovery account
Regulatory Assets and Liabilities
Net liability	$ (252)	$ (439)
Regulatory balancing accounts | New system generation balancing account
Regulatory Assets and Liabilities
Net liability	(195)	(171)
Refunds of excess revenue | Significant Components
Regulatory Assets and Liabilities
Net liability	(2,084)	(2,002)
Refunds of excess revenue | Public purpose programs and energy efficiency programs
Regulatory Assets and Liabilities
Net liability	(828)	(683)
Refunds of excess revenue | Tax accounting memorandum account and pole loading balancing account
Regulatory Assets and Liabilities
Net liability	(68)	(248)
Refunds of excess revenue | Base rate recovery balancing account
Regulatory Assets and Liabilities
Net liability	(535)	(319)
Refunds of excess revenue | Greenhouse gas auction revenue
Regulatory Assets and Liabilities
Net liability	(4)	(75)
Refunds of excess revenue | FERC balancing accounts
Regulatory Assets and Liabilities
Net liability	40	74
Refunds of excess revenue | Department of Energy litigation memorandum account
Regulatory Assets and Liabilities
Net liability	(122)	0
Refunds of excess revenue | Other
Regulatory Assets and Liabilities
Net liability	$ (120)	$ (141)