Investments (Nuclear Decommissioning Trusts) (Details) - Southern California Edison - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Other Investments [Line Items]
Unrealized holding gains, net of losses	$ 1,500	$ 1,500
Deferred income taxes related to unrealized gains	373
Nuclear decommissioning trusts	$ 4,000

Amount before tax of unrealized gain (loss) in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

No definition available.

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant