Long-Term Debt (Long-Term Debt) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Debt Instrument [Line Items]
Total debt	$ 5,451	[1]	$ 3,436	[1]
Secured Debt [Member]
Debt Instrument [Line Items]
Unamortized premium	14		0
Unamortized discount	(11)		0
Secured Debt [Member] | 6.875% Fixed Senior Secured First Lien Notes due August 15, 2017 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	250		0
Stated interest rate (as a percent)	6.875%
Secured Debt [Member] | 9.75% Fixed Senior Secured First Lien Notes due October 15, 2019 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	141		141
Stated interest rate (as a percent)	9.75%
Secured Debt [Member] | 10% Fixed Senior Secured First Lien Notes due December 1, 2020 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	2,180		2,180
Stated interest rate (as a percent)	10.00%
Secured Debt [Member] | 11% Senior Secured Second Lien Notes due October 1, 2021 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	406		406
Stated interest rate (as a percent)	11.00%
Secured Debt [Member] | 11.75% Senior Secured Second Lien Notes due March 1, 2022 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	1,750		0
Total debt	4,730		2,727
Stated interest rate (as a percent)	11.75%
Push Down Debt [Member]
Debt Instrument [Line Items]
Unamortized premium	3	[2]	3	[2]
Total debt	721	[2]	709	[2]
Push Down Debt [Member] | 9.75% Fixed Senior Secured First Lien Notes due October 15, 2019 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	57	[2]	57	[2]
Stated interest rate (as a percent)	9.75%	[2]
Push Down Debt [Member] | 10% EFH Corp. Fixed Senior Secured Notes due January 15, 2020 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	331	[2]	331	[2]
Stated interest rate (as a percent)	10.00%	[2]
Push Down Debt [Member] | 10.875% EFH Corp. Fixed Senior Notes due November 1, 2017 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	98	[2]	98	[2]
Stated interest rate (as a percent)	10.875%	[2]
Push Down Debt [Member] | 11.25/12.00% EFH Corp. Senior Toggle Notes due November 1, 2017 [Member]
Debt Instrument [Line Items]
Long-term debt, gross	$ 232	[2]	$ 220	[2]
Minimum [Member] | Push Down Debt [Member] | 11.25/12.00% EFH Corp. Senior Toggle Notes due November 1, 2017 [Member]
Debt Instrument [Line Items]
Effective interest rate (as a percent)	11.25%	[2]
Maximum [Member] | Push Down Debt [Member] | 11.25/12.00% EFH Corp. Senior Toggle Notes due November 1, 2017 [Member]
Debt Instrument [Line Items]
Effective interest rate (as a percent)	12.00%	[2]

[1] EFIH had no long-term debt due currently at September 30, 2012 and December 31, 2011.

[2] Represents 50% of the amount of these EFH Corp. securities guaranteed by EFIH and pushed down per the discussion below under "Guarantees and Push Down of EFH Corp. Debt."