Summary of Significant Accounting Policies (Revenue Recognition) (Details) - SCE - USD ($) $ in Millions	1 Months Ended		12 Months Ended
	Dec. 31, 2020	Jul. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Public Utilities, General Disclosures [Line Items]
Franchise fees billed to customers			$ 131	$ 122	$ 133
Rate recovery period			24 months
CPUC
Public Utilities, General Disclosures [Line Items]
Requested increase rate amount	$ 214	$ 505
CPUC | 2018 GRC
Public Utilities, General Disclosures [Line Items]
Impact of decision non-core impairment of utility core earnings, net of tax				65
Reduction in authorized revenue				289
Impact of decision non-core impairment of utility property, plant and equipment				170
Impact of decision non-core impairment of utility property, plant and equipment, net of tax				$ 123
Requested increase rate amount	$ 204	$ 478
CPUC | 2021 GRC
Public Utilities, General Disclosures [Line Items]
Requested test year revenue requirement			$ 7,600
Requested increase rate amount			$ 1,300