Summary of Significant Accounting Policies (Energy Credits and Allowances) (Details) (Southern California Edison, USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Other Current Assets [Member]
Summary of Significant Accounting Policies [Line Items]
Greenhouse Gas Allowances	$ 135	$ 41
Other Current Liabilities [Member]
Summary of Significant Accounting Policies [Line Items]
Greenhouse Gas Emission Obligations	$ 102	$ 0