Commitments and Contingencies (Wildfire loss expense) (Details) - 2017/2018 Wildfire/Mudslide Events - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Loss Contingencies [Line Items]
Charge for wildfire-related claims	$ 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
Income tax benefit	(304)	(339)	(304)	(339)
Total after-tax charge	$ 894	$ 874	894	$ 874
SCE
Loss Contingencies [Line Items]
Expected insurance recoveries			$ (708)