Regulatory Assets and Liabilities (Schedule of Regulatory Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Regulatory Liabilities [Line Items]
Current regulatory liabilities	$ 1,532	$ 1,121
Long-term regulatory liabilities	8,329	8,614
SCE
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1,532	1,121
Long-term regulatory liabilities	8,329	8,614
Total regulatory liabilities	9,861	9,735
SCE | Regulatory balancing accounts
Regulatory Liabilities [Line Items]
Current regulatory liabilities	1,080	1,009
Long-term regulatory liabilities	1,344	1,316
SCE | Energy derivatives
Regulatory Liabilities [Line Items]
Current regulatory liabilities	158	74
SCE | Other
Regulatory Liabilities [Line Items]
Current regulatory liabilities	294	38
Long-term regulatory liabilities	125	64
SCE | Costs of removal
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	2,769	2,741
SCE | Re-measurement of deferred taxes
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	2,776	2,892
SCE | Recoveries in excess of ARO liabilities
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	1,130	1,575
SCE | Other postretirement benefits
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	$ 185	$ 26