Variable Interest Entities (Trusts' Income Statement) (Details) - SCE - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
Trust II
Variable Interest Entity [Line Items]
Dividend income	$ 5	$ 5
Dividend distributions	5	5
Trust III
Variable Interest Entity [Line Items]
Dividend income	4	4
Dividend distributions	4	4
Trust IV
Variable Interest Entity [Line Items]
Dividend income	4	4
Dividend distributions	4	4
Trust V
Variable Interest Entity [Line Items]
Dividend income	4	4
Dividend distributions	4	4
Trust VI
Variable Interest Entity [Line Items]
Dividend income	6	6
Dividend distributions	$ 6	$ 6