Commitments and Contingencies (Contingencies) (Details) - USD ($) $ in Millions	Sep. 30, 2017	Dec. 31, 2016
Regulatory Assets [Line Items]
Regulatory assets	$ 8,028	$ 7,455
Southern California Edison
Regulatory Assets [Line Items]
Regulatory assets	8,028	7,455
Southern California Edison \| San Onofre
Regulatory Assets [Line Items]
Regulatory assets	$ 730	$ 857

Carrying amount as of the balance sheet date of capitalized costs of regulated entities that are not expected to be recovered through revenue sources within one year or the normal operating cycle if longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 340
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6499975&loc=d3e44250-110382

Name:	us-gaap_RegulatoryAssetsNoncurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant