Variable Interest Entities (VIEs) (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Variable Interest Entity [Line Items]
Operating Revenues	$ 2,314	$ 2,249	$ 5,449	$ 5,472
Operation and Maintenance	761	800	1,424	1,656
PSE And G [Member]
Variable Interest Entity [Line Items]
Maximum exposure to loss	16		16		$ 16
Operating Revenues	1,466	1,435	3,468	3,580
Operation and Maintenance	368	362	780	824
Long Island ServCo [Member]
Variable Interest Entity [Line Items]
Operating Revenues	84	111	166	200
Operation and Maintenance	$ 84	$ 111	$ 166	$ 200