Income Taxes (Tax Rate Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Income Tax Disclosures [Line Items]
Income from continuing operations before income taxes	$ 352	$ 333
Provision for income tax at federal statutory rate of 35%	124	117
Increase in income tax from:
State tax, net of federal benefit	10	6
Property-related	(113)	(79)
Change related to uncertain tax positions	(12)	(1)
Shared-based compensation	(43)	(10)
Other	(6)	(5)
Total income tax (benefit) expense from continuing operations	$ (40)	$ 28
Effective tax rate	(11.40%)	8.40%
Federal statutory rate	35.00%	35.00%
Southern California Edison
Income Tax Disclosures [Line Items]
Income from continuing operations before income taxes	$ 392	$ 367
Provision for income tax at federal statutory rate of 35%	137	128
Increase in income tax from:
State tax, net of federal benefit	13	9
Property-related	(113)	(79)
Change related to uncertain tax positions	(11)	(1)
Shared-based compensation	(8)	(8)
Other	(6)	(7)
Total income tax (benefit) expense from continuing operations	$ 12	$ 42
Effective tax rate	3.10%	11.40%
Federal statutory rate	35.00%	35.00%
Tax benefits from abandonment loss	$ 39
State
Increase in income tax from:
Shared-based compensation	6	$ 3
State | Southern California Edison
Increase in income tax from:
Shared-based compensation	1	$ 2
Tax benefits from abandonment loss	1,140
Federal | Southern California Edison
Increase in income tax from:
Tax benefits from abandonment loss	$ 698