Summary of Significant Accounting Policies (Cash) (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022	Mar. 31, 2022	Dec. 31, 2021
Restricted Cash and Cash Equivalents Items [Line Items]
Money market funds	$ 136	$ 784
Cash and cash equivalents	836	914
Short-term restricted cash	$ 2	$ 3
Restricted Cash, Current, Statement of Financial Position [Extensible Enumeration]	Other Assets, Current	Other Assets, Current
Total cash, cash equivalents, and restricted cash	$ 838	$ 917	$ 234	$ 394
SCE
Restricted Cash and Cash Equivalents Items [Line Items]
Money market funds		647
Cash and cash equivalents	690	766
Total cash, cash equivalents, and restricted cash	$ 690	$ 766	$ 119	$ 280