Regulatory Assets and Liabilities (Textual) (Details) (San Onofre (nuclear), Southern California Edison, USD $) In Millions, unless otherwise specified	1 Months Ended	9 Months Ended
	Jun. 30, 2013	Sep. 30, 2013
Regulatory Assets [Line Items]
Net regulatory asset		$ 1,450
Cost of service	56	(129)
Property, plant and equipment
Regulatory Assets [Line Items]
Net regulatory asset		1,540
Estimated losses on disposal of nuclear fuel inventory
Regulatory Assets [Line Items]
Net regulatory asset		$ 33