Leases (Schedule Of Lease Assets and Liabilities Recorded in Consolidated Balance Sheets) (Parenthetical) (Detail) $ in Millions	Dec. 31, 2019 USD ($)
Utility Plant, Net
Finance lease assets, accumulated amortization	$ 24

Finance lease right of use asset accumulated amortization.

No definition available.

Name:	ck91882_FinanceLeaseRightOfUseAssetAccumulatedAmortization
Namespace Prefix:	ck91882_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant