Summary of Significant Accounting Policies (Details) mi² in Thousands, $ in Millions	3 Months Ended				9 Months Ended		33 Months Ended
	Sep. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)	Sep. 30, 2014 USD ($)	Mar. 31, 2014 USD ($)	Sep. 30, 2015 USD ($) mi²	Sep. 30, 2014 USD ($)	Sep. 30, 2015 USD ($)
Summary of Significant Accounting Policies [Line Items]
Impairment and other charges	$ 0		$ (3)		$ 0	$ 228
Southern California Edison
Summary of Significant Accounting Policies [Line Items]
Impairment and other charges	$ 0		$ 0		$ 0	$ 231
Southern California Edison | Electric Utility
Summary of Significant Accounting Policies [Line Items]
Supply of electricity, area covered (square mile) | mi²					50
San Onofre | Southern California Edison
Summary of Significant Accounting Policies [Line Items]
Impairment and other charges		$ 163		$ 231			$ 738
Asset impairment net of tax		$ 72		$ 96			$ 437