Pension And OPEB (Schedule Of Pension And OPEB Costs) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Benefit Costs	$ 1	$ 14	$ 3	$ 42
Pension Benefits [Member] | PSE And G [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Benefit Costs	(1)	8	(3)	22
Pension Benefits [Member] | Power [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Benefit Costs	0	3	1	11
Pension Benefits [Member] | Other Entity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Benefit Costs	2	3	5	9
OPEB [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Benefit Costs	21	18	64	53
OPEB [Member] | PSE And G [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Benefit Costs	13	11	40	33
OPEB [Member] | Power [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Benefit Costs	7	6	20	17
OPEB [Member] | Other Entity [Member]
Defined Benefit Plan Disclosure [Line Items]
Total Benefit Costs	$ 1	$ 1	$ 4	$ 3