Summary of Significant Accounting Policies (Regulatory Proceedings) (Details) - USD ($) $ in Millions	1 Months Ended		3 Months Ended	6 Months Ended	12 Months Ended
	May 31, 2019	Apr. 30, 2019	Jun. 30, 2019	Jun. 30, 2019	Dec. 31, 2018
CPUC | 2018 GRC
Public Utilities, General Disclosures [Line Items]
Approved decision escalate capital additions, year two, percent	2.49%
Southern California Edison
Public Utilities, General Disclosures [Line Items]
Increase (decrease) in revenue requirement				$ 290
Current effective retail base transmission revenue requirement				1,040
Southern California Edison | CPUC
Public Utilities, General Disclosures [Line Items]
Additional ROE		6.00%
Southern California Edison | CPUC | 2018 GRC
Public Utilities, General Disclosures [Line Items]
Approved revenue requirement year one	$ 5,451
Approved decision escalate capital additions, year one, percent	2.49%
Approved revenue requirement year two	$ 5,863
Impact of decision non-core impairment of utility core earnings, net of tax			$ 131
Reduction in revenue			(265)
Reduction in authorized revenue	$ 5,116		(289)
Increase in approved revenue			24
Refund to customers			554
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
Southern California Edison | FERC
Public Utilities, General Disclosures [Line Items]
Increase (decrease) in revenue requirement				$ (131)
Decrease in revenue requirement percent				11.00%
FERC Base ROE		17.12%			10.30%
Conventional ROE		11.12%
Additional ROE		6.00%
Southern California Edison | CAISO
Public Utilities, General Disclosures [Line Items]
Additional ROE		0.50%
Southern California Edison | FERC and CAISO
Public Utilities, General Disclosures [Line Items]
FERC Base ROE		18.40%