Commitments And Contingencies (General Litigation) (Details) (Pepco [Member], USD $) In Millions, unless otherwise specified	6 Months Ended	9 Months Ended
Jun. 30, 2011	Sep. 30, 2011
Pepco [Member]
Number of plaintiffs		448
Compensatory damages		$ 2
Punitive damages		4
Cases still pending against Pepco		180
Cases filed		90
Monetary damages sought in the remaining suits	$ 360

The total amount of pending claims pertaining to a loss contingency accrual as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 5

-Paragraph 9, 10, 11, 12

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Name:	us-gaap_LossContingencyPendingClaimsNumber
Namespace Prefix:	us-gaap
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant