Membership Interests (Narrative) (Details)	Sep. 30, 2012
Distribution Restrictions [Line Items]
Consolidated leverage ratio related to dividend restrictions covenant (as a ratio)	6
Consolidated leverage ratio related to dividend restrictions, actual ratio (as a ratio)	6.3

Consolidated leverage ratio threshold related to a debt indenture covenant restricting the entitiy's ability to pay dividends or make other distributions in respect of the entitiy's common shares.

No definition available.

Name:	efh_ConsolidatedLeverageRatioRelatedToDividendRestrictionsCovenantThreshold
Namespace Prefix:	efh_
Data Type:	xbrli:decimalItemType
Balance Type:	na
Period Type:	instant