Regulatory Assets and Liabilities (Balancing Accounts) (Details) - SCE - USD ($) $ in Millions	Jul. 31, 2021	Jun. 30, 2021	Dec. 31, 2020
Regulatory balancing and memorandum accounts-asset | Significant components
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		$ 2,050	$ 1,388
Regulatory balancing and memorandum accounts-asset | Portfolio allocation balancing account
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		543	497
Regulatory balancing and memorandum accounts-asset | Base revenue requirement balancing account
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		665	622
Regulatory balancing and memorandum accounts-asset | FERC balancing account
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		32	12
Regulatory balancing and memorandum accounts-asset | Wildfire and drought restoration accounts
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		396	361
Costs not yet approved	$ 8
Regulatory balancing and memorandum accounts-asset | Wildfire-related memorandum accounts
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		1,404	1,104
Regulatory balancing and memorandum accounts-asset | COVID 19-related memorandum accounts
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		78	176
Regulatory balancing and memorandum accounts-asset | Customer service re-platform memorandum account
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		61	30
Regulatory balancing and memorandum accounts-asset | Residential uncollectibles balancing account
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		157
Regulatory balancing and memorandum accounts-asset | Other
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		83
Revenue subject to refund-liability | Energy resource recovery account
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		(95)	(89)
Revenue subject to refund-liability | New system generation balancing account
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		(28)	(10)
Revenue subject to refund-liability | Public purpose programs and energy efficiency programs
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		(1,137)	(1,130)
Revenue subject to refund-liability | Greenhouse gas auction revenue and low carbon fuel standard revenue
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)		$ (109)	(125)
Revenue subject to refund-liability | Other
Regulatory Assets and Liabilities
Net regulatory assets (liabilities)			$ (60)