Income Taxes (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	0 Months Ended			9 Months Ended			16 Months Ended	9 Months Ended
	Jun. 26, 2009	Sep. 15, 2008	Dec. 17, 2007	Sep. 30, 2012 Year	Sep. 30, 2012 Power [Member]	Sep. 30, 2012 PSEG [Member]	Dec. 31, 2011 PSEG [Member]	Sep. 30, 2012 PSE And G [Member]
Component of Other Expense, Nonoperating [Line Items]
Bonus depreciation for tax purposes						50.00%	100.00%
Average tax benefits recognition period				20
Investment tax credit								$ 21
Decrease in unrecognized tax benefits reasonably likely to increase or decrease within one year						533	146
Tax benefits from IRS settlement in leasing issue						387
Impact Of unrecognized tax						216
Interest and penalties for decrease in uncertain tax position						356
Amount of unrecognized tax benefits that would affect the effective tax rate				317
Tax deposit	140	80	100
Unrecognized tax benefit decrease on settlement with IRS					$ 1	$ 70		$ 30