Regulatory Assets and Liabilities (Schedule of Regulatory Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Regulatory Liabilities [Line Items]
Current regulatory liabilities	$ 569	$ 972
Long-term regulatory liabilities	8,589	8,385
SCE
Regulatory Liabilities [Line Items]
Current regulatory liabilities	569	972
Long-term regulatory liabilities	8,589	8,385
Total regulatory liabilities	9,158	9,357
SCE | Regulatory balancing and memorandum accounts
Regulatory Liabilities [Line Items]
Current regulatory liabilities	471	883
Long-term regulatory liabilities	1,062	1,261
SCE | Energy derivatives
Regulatory Liabilities [Line Items]
Current regulatory liabilities	87	80
SCE | Other
Regulatory Liabilities [Line Items]
Current regulatory liabilities	11	9
Long-term regulatory liabilities	48	41
SCE | Costs of removal
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	2,595	2,674
SCE | Re-measurement of deferred taxes
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	2,283	2,424
SCE | Recoveries in excess of ARO liabilities
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	1,930	1,569
SCE | Other postretirement benefits
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	$ 671	$ 416