Fair Value Measurements (Fair Value Of Debt) (Detail) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012		Dec. 31, 2011
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-Term Debt, Carrying Amount	$ 8,309		$ 8,094
Long-Term Debt, Fair Value	9,824		9,283
Power - Recourse Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-Term Debt, Carrying Amount	2,686	[1]	2,751	[1]
Long-Term Debt, Fair Value	3,205	[1]	3,158	[1]
PSE And G [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-Term Debt, Carrying Amount	4,744	[1]	4,270	[1]
Long-Term Debt, Fair Value	5,631	[1]	4,905	[1]
Transition Funding (PSE&G) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-Term Debt, Carrying Amount	746	[1]	895	[1]
Long-Term Debt, Fair Value	832	[1]	1,016	[1]
Transition Funding II (PSE&G) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-Term Debt, Carrying Amount	39	[1]	44	[1]
Long-Term Debt, Fair Value	41	[1]	47	[1]
Energy Holdings Project Level, Non-Recourse Debt [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-Term Debt, Carrying Amount	45	[2]	95	[2]
Long-Term Debt, Fair Value	45	[2]	95	[2]
DH [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Non-Recourse Debt			50
Fair value of non-recourse debt			45
PSEG [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Long-Term Debt, Carrying Amount	49	[3]	39	[3]
Long-Term Debt, Fair Value	$ 70	[3]	$ 62	[3]

[1] The debt fair valuation is based on the present value of each bond’s future cash flows. The discount rates used in the present value analysis are based on an estimate of new issue bond yields across the treasury curve. When a bond has embedded options, an interest rate model is used to reflect the impact of interest rate volatility into the analysis (primarily Level 2 measurements).

[2] Fair value amounts as of December 31, 2011 include $50 million of non-recourse project debt related to Dynegy which is classified as a Level 3 measurement. See “Fair Value Option” above for more details on Dynegy debt. Non-recourse project debt of $45 million is valued as equivalent to the amortized cost and is classified as a Level 3 measurement.

[3] Fair value represents net offsets to debt resulting from adjustments from interest rate swaps entered into to hedge certain debt at Power and the unamortized premium resulting from a debt exchange entered into between Power and Energy Holdings.