Commitments and Contingencies (Wildfires litigation) (Details) $ in Millions		1 Months Ended			2 Months Ended	3 Months Ended			9 Months Ended		12 Months Ended
	Oct. 26, 2021 lawsuit plaintiff	Oct. 31, 2021 USD ($)	Jan. 31, 2021 $ / claim	Oct. 31, 2020 USD ($) $ / claim	Apr. 30, 2021 USD ($)	Sep. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2021 USD ($) plaintiff	Sep. 30, 2020 USD ($)	Dec. 31, 2020 USD ($)	Jan. 31, 2019 lawsuit
San Onofre OII
Loss Contingencies [Line Items]
Number of pending lawsuits | lawsuit												2
2017/2018 Wildfire/Mudslide Events
Loss Contingencies [Line Items]
Payments									$ 3,392
Charge for wildfire-related claims						$ 2,256			2,256		$ 4,383
Increase in accrued estimated losses to reflect best estimate						1,265	$ 1,297		1,265	$ 1,297
Expected revenue from FERC customers						67	84		67	84
Total pre-tax charge						1,198	1,213		1,198	1,213
Total after-tax charge						894	$ 874		894	$ 874
2017/2018 Wildfire/Mudslide Events | Settled Litigation
Loss Contingencies [Line Items]
Charge for wildfire-related claims						84			84
2017/2018 Wildfire/Mudslide Events | Pending Litigation
Loss Contingencies [Line Items]
Charge for wildfire-related claims						2,200			2,200
2017/2018 Wildfire/Mudslide Events | Aggregate
Loss Contingencies [Line Items]
Payments									$ 5,200
Thomas and Koenigstein Fires and Montecito Mudslides
Loss Contingencies [Line Items]
Number of pending lawsuits | lawsuit	47
2017/2018 Wildfire/Mudslide Events, Excluding Certain Litigation | Settled Litigation
Loss Contingencies [Line Items]
Number of plaintiffs | plaintiff									4,000
2017/2018 Wildfire/Mudslide Events, Excluding Certain Litigation | Aggregate | Settled Litigation
Loss Contingencies [Line Items]
Payments									$ 1,500
2019/2020 Wildfires
Loss Contingencies [Line Items]
Charge for wildfire-related claims						$ 123			$ 123
SCE | 2017/2018 Wildfire/Mudslide Events | SED Settlement
Loss Contingencies [Line Items]
Charge for wildfire-related claims		$ 550
Fine to State		110
Shareholder-funded safety measures costs		65
Third-party uninsured claims cost recovery waiver		$ 375
SCE | 2017/2018 Wildfire/Mudslide Events | Local Public Entity Settlements
Loss Contingencies [Line Items]
Payments								$ 360
SCE | 2017/2018 Wildfire/Mudslide Events | TKM Subrogation Settlement
Loss Contingencies [Line Items]
Payments				$ 1,200
Payment agreement for each dollar of claim | $ / claim				0.555
SCE | 2017/2018 Wildfire/Mudslide Events | Individual Plaintiff Settlements
Loss Contingencies [Line Items]
Number of plaintiffs | plaintiff									4,000
Payments									$ 1,200		$ 300
SCE | 2017/2018 Wildfire/Mudslide Events | Aggregate
Loss Contingencies [Line Items]
Increase in accrued estimated losses to reflect best estimate									$ 7,500
SCE | Thomas and Koenigstein Fires and Montecito Mudslides
Loss Contingencies [Line Items]
Number of pending lawsuits | lawsuit	73
SCE | December 2017 - Thomas and Koenigstein Wildfires
Loss Contingencies [Line Items]
Number of pending lawsuits | lawsuit	280
Number of plaintiffs | plaintiff	3,000
SCE | Thomas and Koenigstein Fires, Class Action
Loss Contingencies [Line Items]
Number of pending lawsuits | lawsuit	4
SCE | November 2018 - Woolsey Wildfires
Loss Contingencies [Line Items]
Number of pending lawsuits | lawsuit	348
Number of plaintiffs | plaintiff	7,000
SCE | November 2018 - Woolsey Wildfires | Woolsey Subrogation Settlement
Loss Contingencies [Line Items]
Payments					$ 2,200
Payment agreement for each dollar of claim | $ / claim			0.67
SCE | Woolsey Fire, Class Action
Loss Contingencies [Line Items]
Number of pending lawsuits | lawsuit	2