Summary of Significant Accounting Policies (Cash) (Details) - USD ($) $ in Millions	Sep. 30, 2024	Dec. 31, 2023	Sep. 30, 2023	Dec. 31, 2022
Restricted Cash and Cash Equivalents
Money market funds	$ 105	$ 199
Cash and cash equivalents	200	345
Short-term restricted cash	$ 67	35
Restricted Cash, Current, Statement of Financial Position [Extensible Enumeration]	Other Assets, Current
Long-term restricted cash	$ 376	152
Restricted Cash, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent
Total cash, cash equivalents, and restricted cash	$ 643	532	$ 449	$ 917
SCE
Restricted Cash and Cash Equivalents
Money market funds	5	78
Cash and cash equivalents	91	214
Short-term restricted cash	$ 63	33
Restricted Cash, Current, Statement of Financial Position [Extensible Enumeration]	Other Assets, Current
Long-term restricted cash	$ 376	151
Restricted Cash, Noncurrent, Statement of Financial Position [Extensible Enumeration]	Other Assets, Noncurrent
Total cash, cash equivalents, and restricted cash	$ 530	$ 398	$ 318	$ 766