Summary of Significant Accounting Policies (New Accounting Guidance) (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs	$ 81
Southern California Edison
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs	$ 75
Accounting Standards Update 2015-03 | Long-term debt
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs		$ 81
Accounting Standards Update 2015-03 | Other long-term assets
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs		(81)
Accounting Standards Update 2015-03 | Southern California Edison | Long-term debt
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs		77
Accounting Standards Update 2015-03 | Southern California Edison | Other long-term assets
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Debt issuance costs		$ (77)