Revenue (Textual) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Revenue from Contract with Customer [Abstract]
Commercial and other non-residential customers implied term	20 years
Southern California Edison
Public Utilities, General Disclosures [Line Items]
Franchise fees billed to customers	$ 28	$ 29
Rate recovery period	24 months