Income Taxes (Textual) (Details) - USD ($) $ in Millions	1 Months Ended	3 Months Ended	12 Months Ended
	Apr. 30, 2016	Jun. 30, 2016	Dec. 31, 2017	Dec. 31, 2015	Mar. 31, 2017	Dec. 31, 2016
Income Tax Disclosure [Line Items]
Accumulated deferred income net income tax liabilities			$ 4,500
Re-measurement of federal net operating loss carryforwards			466
Unrecognized tax benefits that would impact the effective tax rate			308			$ 347
Tax Years 2007 To 2012
Income Tax Disclosure [Line Items]
Expected refund					$ (7)
Disallowance of Repair Allowance Deduction
Income Tax Disclosure [Line Items]
Base rate offset				$ 324
Rate base offset amortization period (years)				27 years
Capistrano Wind | Affiliated Entity | Tax Allocation Agreement
Income Tax Disclosure [Line Items]
Due to affiliate under tax allocation agreements			199			242
SCE
Income Tax Disclosure [Line Items]
Accumulated deferred income net income tax liabilities			5,000
Changes to earnings charge			33
Granted BRRBA reduction	$ 234
Refund		$ 133
After tax refund		$ 79
Unrecognized tax benefits that would impact the effective tax rate			$ 167			$ 243
SCE | Disallowance of Repair Allowance Deduction
Income Tax Disclosure [Line Items]
Federal tax liability				$ 382