Summary of Significant Accounting Policies (Cash) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022	Sep. 30, 2022	Dec. 31, 2021
Restricted Cash and Cash Equivalents Items [Line Items]
Money market funds	$ 120	$ 784
Cash and cash equivalents	446	914
Short-term restricted cash	$ 3	$ 3
Restricted Cash, Current, Statement of Financial Position [Extensible Enumeration]	Other Assets, Current	Other Assets, Current
Total cash, cash equivalents, and restricted cash	$ 449	$ 917	$ 233	$ 394
SCE
Restricted Cash and Cash Equivalents Items [Line Items]
Money market funds		647
Cash and cash equivalents	317	$ 766
Short-term restricted cash	$ 1
Restricted Cash, Current, Statement of Financial Position [Extensible Enumeration]	Other Assets, Current	Other Assets, Current
Total cash, cash equivalents, and restricted cash	$ 318	$ 766	$ 91	$ 280