Variable Interest Entities (Summary of Trusts' Income Statement) (Details) - Southern California Edison - VIE - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Trust II
Variable Interest Entity
Dividend income	$ 5	$ 5	$ 15	$ 15
Dividend distributions	5	5	15	15
Trust III
Variable Interest Entity
Dividend income	4	4	12	12
Dividend distributions	4	4	12	12
Trust IV
Variable Interest Entity
Dividend income	4	4	13	13
Dividend distributions	4	4	13	13
Trust V
Variable Interest Entity
Dividend income	4	4	12	12
Dividend distributions	4	4	12	12
Trust VI
Variable Interest Entity
Dividend income	6	6	18	18
Dividend distributions	$ 6	$ 6	$ 18	$ 18