Compensation and Benefit Plans (Expense and Tax Benefits of Stock Based Compensation) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 21	$ 23	$ 34
Income tax benefits related to stock compensation expense	6	72	41
Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	11	14	14
Performance shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1	2	13
Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	7	6	6
Other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	2	1	1
SCE
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	11	13	16
Income tax benefits related to stock compensation expense	3	15	20
SCE | Stock options
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	6	8	7
SCE | Performance shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	1	2	6
SCE | Restricted stock units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	4	3	3
SCE | Other
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Stock-based compensation expense	$ 0	$ 0	$ 0