Investments (Trust gain loss) (Details) - SCE - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Investment Holdings [Line Items]
Gross realized gains	$ 77	$ 51	$ 328	$ 165
Gross realized losses	(5)	(2)	(21)	(5)
Net unrealized gains (losses) for equity securities	$ (74)	$ 110	$ (41)	$ 5

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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