Summary of Significant Accounting Policies (Cash) (Details) - USD ($) $ in Millions	Mar. 31, 2024	Dec. 31, 2023	Mar. 31, 2023	Dec. 31, 2022
Restricted Cash and Cash Equivalents
Money market funds	$ 123
Cash and cash equivalents	992	$ 345
Short-term restricted cash	$ 67	$ 35
Restricted Cash, Current, Statement of Financial Position [Extensible Enumeration]	Other Assets, Current	Other Assets, Current
Long-term restricted cash	$ 228	$ 152
Restricted Cash, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Total cash, cash equivalents, and restricted cash	$ 1,287	$ 532	$ 838	$ 917
SCE
Restricted Cash and Cash Equivalents
Money market funds	199
Cash and cash equivalents	850	214
Short-term restricted cash	$ 64	$ 33
Restricted Cash, Current, Statement of Financial Position [Extensible Enumeration]	Other Assets, Current	Other Assets, Current
Long-term restricted cash	$ 228	$ 151
Restricted Cash, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent	Other Assets, Noncurrent
Total cash, cash equivalents, and restricted cash	$ 1,142	$ 398	$ 690	$ 766