Property, Plant and Equipment (Textual) (Details) - SCE - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment [Line Items]
Capitalized software costs	$ 1,100	$ 1,400
Capitalized software, accumulated amortization	600	800
Capitalized software, amortization expense	233	$ 249	$ 268
Capitalized software, estimated amortization year 1	176
Capitalized software, estimated amortization year 2	127
Capitalized software, estimated amortization year 3	92
Capitalized software, estimated amortization year 4	62
Capitalized software, estimated amortization year 5	$ 26
Capitalized software costs | Minimum
Property, Plant and Equipment [Line Items]
Estimated useful lives	5 years
Capitalized software costs | Maximum
Property, Plant and Equipment [Line Items]
Estimated useful lives	10 years