Summary of Significant Accounting Policies (Revenue) (Details) - SCE - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Aug. 31, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Public Utilities, General Disclosures [Line Items]
Franchise fees billed to customers		$ 147	$ 131	$ 122
2021 General Rate Case
Public Utilities, General Disclosures [Line Items]
Approved rate amount	$ 6,900
Approved regulatory increase (decrease)	$ 1,000