Regulatory Assets and Liabilities (Schedule of Regulatory Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Regulatory Liabilities [Line Items]
Current regulatory liabilities	$ 801	$ 972
Long-term regulatory liabilities	8,089	8,385
Southern California Edison
Regulatory Liabilities [Line Items]
Current regulatory liabilities	801	972
Long-term regulatory liabilities	8,089	8,385
Total regulatory liabilities	8,890	9,357
Southern California Edison | Regulatory balancing and memorandum accounts
Regulatory Liabilities [Line Items]
Current regulatory liabilities	744	883
Long-term regulatory liabilities	1,047	1,261
Southern California Edison | Energy derivatives
Regulatory Liabilities [Line Items]
Current regulatory liabilities	45	80
Southern California Edison | Other
Regulatory Liabilities [Line Items]
Current regulatory liabilities	12	9
Long-term regulatory liabilities	35	41
Southern California Edison | Cost of removal
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	2,585	2,674
Southern California Edison | Re-measurement of deferred taxes
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	2,318	2,424
Southern California Edison | Recoveries in excess of ARO liabilities
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	1,677	1,569
Southern California Edison | Other postretirement benefits
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	$ 427	$ 416