Accumulated Other Comprehensive Income (Loss), Net Of Tax (Schedule Of Accumulated Other Comprehensive Income (Loss)) (Detail) (USD $) In Millions, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011	Dec. 31, 2010
Derivative Contracts	$ 21	$ 31	$ 54	$ 111
Pension and OPEB Plans	(423)	(438)	(328)	(377)
NDT Fund	88	66	92	109
Other	4	4	3	1
Accumulated Other Comprehensive Income (Loss)	(310)	(337)	(179)	(156)
Power [Member]
Accumulated Other Comprehensive Income (Loss)	(250)	(276)
PSE And G [Member]
Accumulated Other Comprehensive Income (Loss)	1	2
Other Comprehensive Income (Loss) [Member] | Power [Member]
Derivative Contracts	(10)		(57)
Pension and OPEB Plans	14		42
NDT Fund	22		(17)
Other	0		0
Accumulated Other Comprehensive Income (Loss)	26		(32)
Other Comprehensive Income (Loss) [Member] | PSE And G [Member]
Derivative Contracts	0		0
Pension and OPEB Plans	0		0
NDT Fund	0		0
Other	(1)		1
Accumulated Other Comprehensive Income (Loss)	(1)		1
Other Comprehensive Income (Loss) [Member] | Other [Member]
Derivative Contracts	0		0
Pension and OPEB Plans	1		7
NDT Fund	0		0
Other	1		1
Accumulated Other Comprehensive Income (Loss)	$ 2		$ 8