Regulatory Assets and Liabilities (Schedule of Regulatory Liabilities) (Details) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Regulatory Liabilities [Line Items]
Current regulatory liabilities	$ 903	$ 756
Long-term regulatory liabilities	5,961	5,726
Southern California Edison
Regulatory Liabilities [Line Items]
Current regulatory liabilities	903	756
Long-term regulatory liabilities	5,961	5,726
Total regulatory liabilities	6,864	6,482
Southern California Edison | Regulatory balancing accounts
Regulatory Liabilities [Line Items]
Current regulatory liabilities	822	736
Long-term regulatory liabilities	1,326	1,180
Southern California Edison | San Onofre MHI arbitration award
Regulatory Liabilities [Line Items]
Current regulatory liabilities	47	0
Southern California Edison | Other
Regulatory Liabilities [Line Items]
Current regulatory liabilities	34	20
Long-term regulatory liabilities	57	60
Southern California Edison | Costs of removal
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	2,820	2,847
Southern California Edison | Recoveries in excess of ARO liabilities
Regulatory Liabilities [Line Items]
Long-term regulatory liabilities	$ 1,758	$ 1,639