Fair Value Measurements (Narrative) (Detail) (USD $)						9 Months Ended				12 Months Ended
	Sep. 30, 2013		Dec. 31, 2012		Sep. 30, 2012	Sep. 30, 2013 Power [Member]		Dec. 31, 2012 Power [Member]		Dec. 31, 2012 Minimum [Member] MMBTU [Member] Long-Term Gas Supply [Member]	Dec. 31, 2012 Maximum [Member] MMBTU [Member] Long-Term Gas Supply [Member]
Minimum Number of Pricing Inputs						2
Longer-Term Basis Range										0	4
Current liabilities, fair value	$ 36,000,000	[1]	$ 46,000,000	[1]		$ 36,000,000	[1]	$ 46,000,000	[1]
Net assets measured at fair value on a recurring basis	1,900,000,000				1,800,000,000
Net assets measured at fair value on a recurring basis measured using unobservable input and as Level 3	$ (46,000,000)				$ (21,000,000)

[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 September 30, 2013 and December 31, 2012. PSE&G does not have any derivative contracts subject to master netting or similar agreements.