Financial Risk Management Activities (Schedule Providing Credit Risk From Others, Net Of Collateral) (Detail) - Power [Member] $ in Millions	Mar. 31, 2016 USD ($)
Derivative [Line Items]
Current Exposure	$ 582
Securities held as Collateral	231
Net exposure	351
Number of Counterparties greater than 10%	1
Amount Of Net Credit Exposure Greater Than Ten Percent	178
Investment Grade - External Rating [Member]
Derivative [Line Items]
Current Exposure	542
Securities held as Collateral	230
Net exposure	312
Number of Counterparties greater than 10%	1
Amount Of Net Credit Exposure Greater Than Ten Percent	178	[1]
Non-Investment Grade - External Rating [Member]
Derivative [Line Items]
Current Exposure	30
Securities held as Collateral	0
Net exposure	30
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	10
Securities held as Collateral	1
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	0
Securities held as Collateral	0
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	16
Letter of Credit [Member]
Derivative [Line Items]
Securities held as Collateral	$ 215

[1] Represents net exposure with PSE&G.