Derivative Instruments (Balance Sheet Disclosures) (Details) - Southern California Edison Company - Commodity derivative contracts - USD ($)	Mar. 31, 2017	Dec. 31, 2016
Other current assets
Net Liability
Cash collateral	$ 0
Other current liabilities
Net Liability
Collateral received		$ 2,000,000
Electric Utility
Derivative Assets
Gross amounts recognized	71,000,000	75,000,000
Gross amounts offset in the consolidated balance sheets	(1,000,000)	(1,000,000)
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	70,000,000	74,000,000
Derivative Liabilities
Gross amounts recognized	1,227,000,000	1,158,000,000
Gross amounts offset in the consolidated balance sheets	(1,000,000)	(1,000,000)
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	1,226,000,000	1,157,000,000
Net Liability
Gross amounts recognized	1,156,000,000	1,083,000,000
Gross amounts offset in the consolidated balance sheets	0	0
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	1,156,000,000	1,083,000,000
Electric Utility | Derivative Assets, Short-Term
Derivative Assets
Gross amounts recognized	70,000,000	74,000,000
Gross amounts offset in the consolidated balance sheets	(1,000,000)	(1,000,000)
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	69,000,000	73,000,000
Electric Utility | Derivative Assets, Long-Term
Derivative Assets
Gross amounts recognized	1,000,000	1,000,000
Gross amounts offset in the consolidated balance sheets	0	0
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	1,000,000	1,000,000
Electric Utility | Derivative Liability, Short-Term
Derivative Liabilities
Gross amounts recognized	238,000,000	217,000,000
Gross amounts offset in the consolidated balance sheets	(1,000,000)	(1,000,000)
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	237,000,000	216,000,000
Electric Utility | Derivative Liability, Long-Term
Derivative Liabilities
Gross amounts recognized	989,000,000	941,000,000
Gross amounts offset in the consolidated balance sheets	0	0
Cash collateral posted	0	0
Net amounts presented in the consolidated balance sheets	$ 989,000,000	$ 941,000,000