Commitments and Contingencies (Environmental Remediation) (Details) - SCE $ in Millions	12 Months Ended
	Dec. 31, 2021 USD ($) site	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Jointly Owned Utility Plant Interests [Line Items]
Recorded estimated minimum liability	$ 260
Environmental remediation regulatory assets	242
Expected recovery from incentive mechanism	$ 39
Expected recovery from incentive mechanism (percent)	90.00%
Recovery through customer rates	$ 203
Recovery through customer rates (percent)	100.00%
Environmental remediation expense	$ 9	$ 7	$ 9
Clean up (period)	40 years
Expected remediation costs, low end of range	$ 7
Expected remediation costs, high end of range	$ 26
Material sites
Jointly Owned Utility Plant Interests [Line Items]
Identified remediation sites (number) | site	26
Minimum estimated liability	$ 1
Recorded estimated minimum liability	257
Cost may exceed liability	114
Material sites | San Onofre
Jointly Owned Utility Plant Interests [Line Items]
Recorded estimated minimum liability	$ 169
Immaterial sites
Jointly Owned Utility Plant Interests [Line Items]
Identified remediation sites (number) | site	14
Recorded estimated minimum liability	$ 3
Cost may exceed liability	$ 9