Regulatory Assets and Liabilities (Liabilities) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Regulatory Liabilities [Line Items]
Current regulatory liabilities	$ 583	$ 569
Long-term regulatory liabilities	8,584	8,589
SCE
Regulatory Liabilities [Line Items]
Current regulatory liabilities	583	569
Long-term regulatory liabilities	8,584	8,589
Total regulatory liabilities	9,167	9,158
SCE | Revenue subject to refund-liability
Regulatory Liabilities [Line Items]
Current regulatory liabilities	347	471
Long-term regulatory liabilities	736	1,062
SCE | Energy derivatives
Regulatory Liabilities [Line Items]
Current regulatory liabilities	205	87
SCE | Other regulatory assets or liabilities
Regulatory Liabilities [Line Items]
Current regulatory liabilities	31	11
Long-term regulatory liabilities	55	48
SCE | Costs of removal
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	2,735	2,595
SCE | Re-measurement of deferred taxes
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	2,332	2,283
SCE | Recoveries in excess of ARO liabilities
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	2,047	1,930
SCE | Other postretirement benefits
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	$ 679	$ 671