Segment Information (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013
Segment Financial Information
Revenues	$ 4,189		$ 3,723
Total revenues	4,189	[1]	3,723	[1]
Depreciation and amortization	266		352
Investment income	22		18
Interest expense	265		258
Income taxes (benefits)	48		114
Income from continuing operations	122		192
Discontinued operations (Note 13)	86		4
NET INCOME (LOSS)	208		196
Total assets	51,228		50,424		50,424
Total goodwill	6,418		6,447		6,418
Property additions	821		826
Intersegment Eliminations [Member]
Segment Financial Information
Revenues	0		0
Operating Segments [Member]
Segment Financial Information
Total revenues	4,189		3,723
Regulated Distribution
Segment Financial Information
Revenues	2,552		2,212
Depreciation and amortization	131		202
Investment income	15		18
Interest expense	151		135
Income taxes (benefits)	125		126
Income from continuing operations	214		210
Discontinued operations (Note 13)	0		0
NET INCOME (LOSS)	214		210
Total assets	27,742		26,943
Total goodwill	5,092		5,025
Property additions	269		436
Regulated Distribution | Intersegment Eliminations [Member]
Segment Financial Information
Revenues	0		0
Regulated Distribution | Operating Segments [Member]
Segment Financial Information
Total revenues	2,552		2,212
Regulated Transmission
Segment Financial Information
Revenues	187		176
Depreciation and amortization	33		29
Investment income	0		0
Interest expense	25		23
Income taxes (benefits)	30		31
Income from continuing operations	51		51
Discontinued operations (Note 13)	0		0
NET INCOME (LOSS)	51		51
Total assets	5,584		4,722
Total goodwill	526		526
Property additions	217		89
Regulated Transmission | Intersegment Eliminations [Member]
Segment Financial Information
Revenues	0		0
Regulated Transmission | Operating Segments [Member]
Segment Financial Information
Total revenues	187		176
Competitive Energy Services
Segment Financial Information
Revenues	1,522		1,414
Depreciation and amortization	91		110
Investment income	14		10
Interest expense	46		73
Income taxes (benefits)	(73)		(24)
Income from continuing operations	(124)		(42)
Discontinued operations (Note 13)	86		4
NET INCOME (LOSS)	(38)		(38)
Total assets	17,445		18,328
Total goodwill	800		896
Property additions	318		283
Competitive Energy Services | Intersegment Eliminations [Member]
Segment Financial Information
Revenues	249		216
Competitive Energy Services | Operating Segments [Member]
Segment Financial Information
Total revenues	1,771		1,630
Other/Corporate
Segment Financial Information
Revenues	(35)		(27)
Depreciation and amortization	11		11
Investment income	3		1
Interest expense	43		27
Income taxes (benefits)	(26)		(19)
Income from continuing operations	(32)		(30)
Discontinued operations (Note 13)	0		0
NET INCOME (LOSS)	(32)		(30)
Total assets	457		431
Total goodwill	0		0
Property additions	17		18
Other/Corporate | Intersegment Eliminations [Member]
Segment Financial Information
Revenues	0		0
Other/Corporate | Operating Segments [Member]
Segment Financial Information
Total revenues	(35)		(27)
Reconciling Adjustments
Segment Financial Information
Revenues	(37)		(52)
Depreciation and amortization	0		0
Investment income	(10)		(11)
Interest expense	0		0
Income taxes (benefits)	(8)		0
Income from continuing operations	13		3
Discontinued operations (Note 13)	0		0
NET INCOME (LOSS)	13		3
Total assets	0		0
Total goodwill	0		0
Property additions	0		0
Reconciling Adjustments | Intersegment Eliminations [Member]
Segment Financial Information
Revenues	(249)		(216)
Reconciling Adjustments | Operating Segments [Member]
Segment Financial Information
Total revenues	$ (286)		$ (268)

[1] Includes excise tax collections of $117 million and $122 million in the three months ended March 31, 2014 and 2013, respectively.