Variable Interest Entities (Trusts' Income Statement) (Details) - SCE - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Trust II
Variable Interest Entity [Line Items]
Dividend income	$ 5	$ 5	$ 10	$ 10
Dividend distributions	5	5	10	10
Trust III
Variable Interest Entity [Line Items]
Dividend income	4	4	8	8
Dividend distributions	4	4	8	8
Trust IV
Variable Interest Entity [Line Items]
Dividend income	5	5	9	9
Dividend distributions	5	5	9	9
Trust V
Variable Interest Entity [Line Items]
Dividend income	4	4	8	8
Dividend distributions	4	4	8	8
Trust VI
Variable Interest Entity [Line Items]
Dividend income	6	6	12	12
Dividend distributions	$ 6	$ 6	$ 12	$ 12