Investments (Trust gain loss) (Details) - SCE - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Mar. 31, 2021
Investment Holdings [Line Items]
Gross realized gains	$ 15	$ 111
Gross realized losses	16	12
Net unrealized (losses) gains for equity securities	$ (100)	$ 18

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