Investments (Gains and (Losses) for Equity Securities) (Details) - Southern California Edison - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Investment Holdings [Line Items]
Gross realized gains	$ 22	$ 26	$ 45	$ 87
Gross realized loss	0	(2)	0	(10)
Net unrealized gains (losses) for equity securities	$ 38	$ (5)	$ 206	$ (68)

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