Summary of Significant Accounting Policies (Leases) (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 1,292	$ 1,442
Operating lease liabilities	$ 1,113	$ 936
SCE
Lessee, Lease, Description [Line Items]
Operating lease term	15 years
Operating lease liabilities	$ 226