Regulatory Assets and Liabilities (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Dec. 31, 2014
Regulatory Assets
Regulatory Assets, Current	$ 473	$ 1,254
Regulatory Asset, Long-term	8,121	7,612
Regulatory Liabilities
Regulatory Liabilities, Current	888	401
Regulatory Liabilities, Long-term	5,265	5,889
California Public Utilities Commission | Scenario, Forecast
Regulatory Liabilities
Decrease in revenue requirement	40
Revenue requirement	(344)
Southern California Edison
Regulatory Assets
Regulatory Assets, Current	473	1,254
Regulatory Asset, Long-term	8,121	7,612
Total Regulatory Assets	8,594	8,866
Regulatory Liabilities
Regulatory Liabilities, Current	888	401
Regulatory Liabilities, Long-term	5,265	5,889
Total Regulatory Liabilities	6,153	6,290
Southern California Edison | Regulatory balancing accounts
Regulatory Assets
Regulatory Assets, Current	287	1,088
Regulatory Asset, Long-term	58	44
Southern California Edison | Energy derivatives
Regulatory Assets
Regulatory Assets, Current	167	159
Regulatory Asset, Long-term	990	850
Southern California Edison | Other
Regulatory Assets
Regulatory Assets, Current	19	7
Regulatory Asset, Long-term	385	351
Regulatory Liabilities
Regulatory Liabilities, Current	341	21
Regulatory Liabilities, Long-term	78	24
Southern California Edison | Deferred income taxes, net
Regulatory Assets
Regulatory Asset, Long-term	3,949	3,405
Southern California Edison | Pensions and other postretirement benefits
Regulatory Assets
Regulatory Asset, Long-term	1,206	1,218
Southern California Edison | Unamortized investments, net
Regulatory Assets
Regulatory Asset, Long-term	198	255
Southern California Edison | San Onofre
Regulatory Assets
Regulatory Asset, Long-term	1,130	1,288
Southern California Edison | Unamortized loss on reacquired debt
Regulatory Assets
Regulatory Asset, Long-term	205	201
Southern California Edison | Regulatory balancing accounts
Regulatory Liabilities
Regulatory Liabilities, Current	547	380
Regulatory Liabilities, Long-term	1,081	1,083
Southern California Edison | Regulatory balancing accounts | California Public Utilities Commission
Regulatory Liabilities
Regulatory Liabilities, Current	318
Southern California Edison | Costs of removal
Regulatory Liabilities
Regulatory Liabilities, Long-term	2,713	2,826
Southern California Edison | Recoveries in excess of ARO liabilities
Regulatory Liabilities
Regulatory Liabilities, Long-term	$ 1,393	$ 1,956