Summary of Significant Accounting Policies (Organization (Details)	9 Months Ended
Sep. 30, 2021 mi²
SCE
Segment Reporting Information [Line Items]
Supply of electricity area covered (in square miles)	50,000

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_SegmentReportingInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration