Investments (Gains and (Losses) for Equity Securities) (Details) - Southern California Edison - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Investment Holdings [Line Items]
Gross realized gains	$ 23	$ 61
Gross realized loss	0	(8)
Net unrealized gains (losses) for equity securities	$ 168	$ (63)

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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