Summary of Significant Accounting Policies (Cash) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
Mar. 31, 2014	Dec. 31, 2013
Cash and Cash Equivalents Items [Line Items]
Maximum maturity period of cash equivalent investments (in months)	3 months
Money market funds	$ 67	$ 68
Cash reclassified to accounts payable	149	168
Southern California Edison
Cash and Cash Equivalents Items [Line Items]
Money market funds	6	8
Cash reclassified to accounts payable	$ 148	$ 163

Investment in short-term money-market instruments (such as commercial paper, banker's acceptances, repurchase agreements, government securities, certificates of deposit, and so forth) which are highly liquid (that is, readily convertible to known amounts of cash) and so near their maturity that they present an insignificant risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify as cash equivalents by definition. Original maturity means an original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three-years ago does not become a cash equivalent when its remaining maturity is three months.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Cash Equivalents

-URI http://asc.fasb.org/extlink&oid=6507016

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant