Financial Risk Management Activities (Schedule Providing Credit Risk From Others, Net Of Collateral) (Detail) - Power [Member] $ in Millions	Sep. 30, 2016 USD ($)
Derivative [Line Items]
Current Exposure	$ 418
Securities held as Collateral	136
Net exposure	282
Number of Counterparties greater than 10%	2
Amount Of Net Credit Exposure Greater Than Ten Percent	147
Investment Grade - External Rating [Member]
Derivative [Line Items]
Current Exposure	384
Securities held as Collateral	135
Net exposure	249
Number of Counterparties greater than 10%	2
Amount Of Net Credit Exposure Greater Than Ten Percent	147	[1]
Non-Investment Grade - External Rating [Member]
Derivative [Line Items]
Current Exposure	24
Securities held as Collateral	0
Net exposure	24
Number of Counterparties greater than 10%	0
Amount Of Net Credit Exposure Greater Than Ten Percent	0
Investment Grade - No External Rating [Member]
Derivative [Line Items]
Current Exposure	9
Securities held as Collateral	0
Net exposure	9
Number of Counterparties greater than 10%	0
Amount Of Net Credit Exposure Greater Than Ten Percent	0
Non-Investment Grade - No External Rating [Member]
Derivative [Line Items]
Current Exposure	1
Securities held as Collateral	1
Net exposure	0
Number of Counterparties greater than 10%	0
Amount Of Net Credit Exposure Greater Than Ten Percent	0
Cash [Member]
Derivative [Line Items]
Securities held as Collateral	3
Letter of Credit [Member]
Derivative [Line Items]
Securities held as Collateral	$ 133

[1] Represents net exposure of $114 million with PSE&G. The remaining net exposure of $33 million is with a non-affiliated power purchaser which is an investment grade counterparty.