Derivative Instruments (Balance Sheet Disclosures) (Details) - SCE - Commodity derivative contracts - Electric Utility - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Derivative Assets
Gross amounts recognized	$ 173	$ 111
Gross amounts offset in the consolidated balance sheets	0	(1)
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	173	110
Derivative Liabilities
Gross amounts recognized	13	3
Gross amounts offset in the consolidated balance sheets	0	(1)
Cash collateral posted	(7)	(1)
Net amounts presented in the consolidated balance sheets	6	1
Net Asset
Gross amounts recognized	(160)	(108)
Gross amounts offset in the consolidated balance sheets	0	0
Cash collateral posted	7	1
Net amounts presented in the consolidated balance sheets	167	109
Derivative Assets, Short-Term
Derivative Assets
Gross amounts recognized	171	106
Gross amounts offset in the consolidated balance sheets	0	(1)
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	171	105
Derivative Assets, Long-Term
Derivative Assets
Gross amounts recognized	2	5
Gross amounts offset in the consolidated balance sheets	0	0
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	2	5
Derivative Liability, Short-Term
Derivative Liabilities
Gross amounts recognized	13	3
Gross amounts offset in the consolidated balance sheets	0	(1)
Cash collateral posted	(7)	(1)
Net amounts presented in the consolidated balance sheets	6	1
Derivative Liability, Long-Term
Derivative Liabilities
Gross amounts recognized	0	0
Gross amounts offset in the consolidated balance sheets	0	0
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	$ 0	$ 0