Commitments and Contingencies (Wildfire Insurance Coverage) (Details) - USD ($) $ in Millions	1 Months Ended				3 Months Ended		9 Months Ended		12 Months Ended
	Aug. 31, 2021	Dec. 31, 2020	Sep. 30, 2020	Jul. 31, 2019	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
SCE
Loss Contingencies [Line Items]
Requested increase (decrease) in revenue requirement		$ 214		$ 505
Regulatory assets		8,434			$ 8,939		$ 8,939		$ 8,434
Wildfire insurance coverage							1,000
Co-insurance					75		75
Self insurance							50
Coverage net							875
Wildfire insurance expense							425
Approved regulatory increase (decrease)			$ 505
Revenue recovery period				2 years
SCE | Wildfire insurance costs
Loss Contingencies [Line Items]
Requested increase (decrease) in revenue requirement		204		$ 478
Wildfire insurance expense	$ 460
2017/2018 Wildfire/Mudslide Events
Loss Contingencies [Line Items]
Increase in accrued estimated losses to reflect best estimate					1,265	$ 1,297	1,265	$ 1,297
2017/2018 Wildfire/Mudslide Events | SCE
Loss Contingencies [Line Items]
Expected insurance recoveries		$ 708							708
Insurance settlements and recoveries							708
Restoration capital expenditures				$ 60
Denied rate increase	8
Potential impairment							187
Expected FERC cumulative recoveries					300		300
Regulatory assets					$ 162		162
Wildfire insurance coverage							1,000
Self insurance							10
2017/2018 Wildfire/Mudslide Events | SCE | Aggregate
Loss Contingencies [Line Items]
Increase in accrued estimated losses to reflect best estimate							7,500
Litigation settlement							5,300
Insurance settlements and recoveries							2,000
November 2018 - Woolsey Wildfires
Loss Contingencies [Line Items]
Litigation settlement									$ 2,212
November 2018 - Woolsey Wildfires | SCE
Loss Contingencies [Line Items]
Wildfire insurance coverage							1,000
Self insurance							$ 10
Thomas and Rye wildfires | SCE
Loss Contingencies [Line Items]
Denied rate increase	$ 6