Summary of Significant Accounting Policies (SCE Dividends) (Details) - SCE - USD ($) $ in Millions			1 Months Ended	12 Months Ended
	Feb. 25, 2021	Jan. 01, 2020	May 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Significant Accounting Policies [Line Items]
Minimum percentage of weighted-average common equity component authorization, set by CPUC (as a percent)		52.00%		48.00%	45.20%
Notification threshold, percent			1.00%
Wildfire related charge incurred after tax					$ 1,800
Weighted-average common equity component authorization, set by CPUC remaining over number of months (in months)				37 months
Weighted-average common equity component of total capitalization percent with CPUC waiver					48.70%
Waiver threshold percent (as a percent)					47.70%
Subsequent event
Significant Accounting Policies [Line Items]
Dividends	$ 325