Income Taxes (Narrative) (Detail) (USD $) In Millions, unless otherwise specified	0 Months Ended			3 Months Ended				16 Months Ended	3 Months Ended
	Jun. 26, 2009	Sep. 15, 2008	Dec. 17, 2007	Mar. 31, 2013 Year	Mar. 31, 2012 Power [Member]	Mar. 31, 2013 PSEG [Member]	Mar. 31, 2012 PSEG [Member]	Dec. 31, 2011 PSEG [Member]	Mar. 31, 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
Tax deposit	$ 140	$ 80	$ 100
Unrecognized tax benefit decrease on settlement with IRS					$ 1	$ 71	$ 71		$ 30