Commitments And Contingent Liabilities (New Generation And Development) (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended		12 Months Ended					6 Months Ended					6 Months Ended	12 Months Ended	6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2011 mW	Dec. 31, 2011 Power [Member] Unit 3 In 2011 [Member] Nuclear Steam Path Capital Additions [Member] mW	Dec. 31, 2012 Power [Member] Unit 2 In 2012 [Member] Nuclear Steam Path Capital Additions [Member] mW	Jun. 30, 2011 Power [Member] Period 2012-2013 [Member] Kearny Site [Member] PJM Interconnection Capital Additions [Member] mW	Jun. 30, 2011 Power [Member] Period 2013-2014 [Member] PJM Interconnection Capital Additions [Member] mW	Jun. 30, 2011 Power [Member] Peach Bottom Units [Member] Nuclear Up Rate Capital Additions [Member] mW	Jun. 30, 2011 PSE&G [Member] Solar Capital Additions [Member]	Jun. 30, 2011 Power [Member] PJM Interconnection Capital Additions [Member]	Jun. 30, 2011 Power [Member] Connecticut Capital Additions [Member]	Mar. 31, 2011 Power [Member] Connecticut Capital Additions [Member] mW	Jun. 30, 2011 Power [Member] Nuclear Steam Path Capital Additions [Member]	Dec. 31, 2011 Power [Member] Nuclear Steam Path Capital Additions [Member] mW	Jun. 30, 2011 Power [Member]	Jun. 30, 2010 Power [Member]	Jun. 30, 2011 PSE&G [Member] mW cubicFeet	Jun. 30, 2010 PSE&G [Member]
Approximate amount committed	$ 1,032							$ 400					$ 192
Increase of MW nominal capacity after completion of upgrades				14	18			133						32
Total expenditures to date	1,002	911						25	150	104	78		68		323	328	674	530
Number of MW of gas fired peaking capacity to be built						178	267					130
Number of MW of solar generation on existing utility poles being installed																	40
Number of MW of installation of solar generation on land and building																	40
Approximately amount of MW's already installed																	21
Number of MW of solar capacity placed into service			23
Long term purchase commitment amount low range										250	130
Approximate amount committed-high end of range										300	140
Investment in projects, amount									$ 117