Commitments and Contingencies (Wildfire loss expense) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
2017/2018 Wildfire/Mudslide Events
Commitments and Contingencies
Charge for wildfire-related claims	$ 90	$ 416
Expected revenue from FERC customers	(6)	(26)
Total pre-tax charge	84	390
Income tax benefit	(23)	(109)
Total after-tax charge	61	281
Post-2018 Wildfires
Commitments and Contingencies
Charge for wildfire-related claims	6	105
Expected insurance recoveries		(96)
Total pre-tax charge	6	9
Income tax benefit	(2)	(2)
Total after-tax charge	$ 4	$ 7