Derivative Instruments (Balance Sheet Disclosures) (Details) - Southern California Edison Company - Commodity derivative contracts - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015
Electric Utility
Derivative Assets
Gross amounts recognized	$ 129	$ 165
Gross amounts offset in the consolidated balance sheets	(2)	(2)
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	127	163
Derivative Liabilities
Gross amounts recognized	1,295	1,335
Gross amounts offset in the consolidated balance sheets	(2)	(2)
Cash collateral posted	(1)	(15)
Net amounts presented in the consolidated balance sheets	1,292	1,318
Net Liability
Gross amounts recognized	1,166	1,170
Gross amounts offset in the consolidated balance sheets	0	0
Cash collateral posted	(1)	(15)
Net amounts presented in the consolidated balance sheets	1,165	1,155
Other Current Assets [Member]
Net Liability
Cash collateral	4	31
Derivative Assets, Long-Term | Electric Utility
Derivative Assets
Gross amounts recognized	67	84
Gross amounts offset in the consolidated balance sheets	0	0
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	67	84
Derivative Liability, Short-Term | Electric Utility
Derivative Liabilities
Gross amounts recognized	226	235
Gross amounts offset in the consolidated balance sheets	(2)	(2)
Cash collateral posted	(1)	(15)
Net amounts presented in the consolidated balance sheets	223	218
Derivative Liability, Long-Term | Electric Utility
Derivative Liabilities
Gross amounts recognized	1,069	1,100
Gross amounts offset in the consolidated balance sheets	0	0
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	1,069	1,100
Derivative Assets, Short-Term | Electric Utility
Derivative Assets
Gross amounts recognized	62	81
Gross amounts offset in the consolidated balance sheets	(2)	(2)
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	$ 60	$ 79