Investments (Trust gain loss) (Details) - SCE - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Investment Holdings [Line Items]
Gross realized gains	$ 140	$ 75	$ 251	$ 114
Gross realized losses	(4)	(1)	(16)	(3)
Net unrealized gains (losses) for equity securities	$ 16	$ 271	$ 34	$ (105)

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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