Interest Expense and Related Charges - Contractual Interest Expense on Pre-Petition Liabilities Classified As Liabilities Subject to Compromise (Details) (Energy Future Intermediate Holding CO LLC [Member], USD $) In Millions, unless otherwise specified	5 Months Ended
	Sep. 30, 2014
Energy Future Intermediate Holding CO LLC [Member]
Contractual Interest Expense On Pre-Petition Liabilities [Line Items]
Contractual Interest Expense On Pre-Petition Liabilities Classified As Liabilities Subject To Compromise	$ 248
Interest Expense On Prepetition Liabilities Recognized In Statement Of Operations, Paid or Accrued Amounts Allowed On Notes Exchanged-Settled	54
Contractual Interest Expense on Prepetition Liabilities Not Recognized in Statement of Operations	$ 194