Fair Value Measurements (Narrative) (Detail) (USD $)	3 Months Ended			6 Months Ended
	Jun. 30, 2013		Jun. 30, 2012	Jun. 30, 2013		Jun. 30, 2012	Dec. 31, 2012
Payments to Acquire Available-for-sale Securities				$ 684,000,000		$ 867,000,000
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Trading Revenue				(8,000,000)		(2,000,000)
Current liabilities, fair value	42,000,000	[1]		42,000,000	[1]		46,000,000	[1]
Net assets measured at fair value on a recurring basis	1,900,000,000		1,700,000,000	1,900,000,000		1,700,000,000
Net assets measured at fair value on a recurring basis measured using unobservable input and as Level 3	(35,000,000)		(36,000,000)	(35,000,000)		(36,000,000)
Power [Member]
Payments to Acquire Available-for-sale Securities				637,000,000		692,000,000
Fair Value, Assets Measured on Recurring Basis, Change in Unrealized Gain (Loss) Included in Trading Revenue	16,000,000		(7,000,000)
Current liabilities, fair value	42,000,000	[1]		42,000,000	[1]		46,000,000	[1]
Minimum [Member] | MMBTU [Member] | Long-Term Gas Supply [Member]
Longer-Term Basis Range				0
Minimum [Member] | MW-Day [Member] | Long Term Electric Capacity [Member]
Forecasted capacity prices				100
Maximum [Member] | MMBTU [Member] | Long-Term Gas Supply [Member]
Longer-Term Basis Range				4
Maximum [Member] | MW-Day [Member] | Long Term Electric Capacity [Member]
Forecasted capacity prices				400
Derivative [Member] | Power [Member]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Transfers, Net	$ 6,000,000			$ 4,000,000

[1] Substantially all of Power's and PSEG's derivative instruments are contracts subject to master netting agreements. Contracts not subject to master netting or similar agreements are immaterial and did not have any collateral posted or received as of June 30, 2013 and December 31, 2012. PSE&G does not have any derivative contracts subject to master netting or similar agreements.