Financial Information by Business Segment (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011		Dec. 31, 2011
Segment Reporting Information [Line Items]
Unaffiliated	$ 2,750		$ 2,753		$ 7,140		$ 7,196
Affiliated	38				38
Total operating revenues	2,788		2,753		7,178		7,196
Depreciation and amortization	174		175		571		508
Net income	157		293		373		656
Add back of noncontrolling interest component	2		2		5		5
Income (loss) from discontinued operations, net of tax	3		0		10		(4)
Total assets	36,651				36,651				34,931
After-tax costs to achieve	132		9		149		27
Franchised Electric [Member]
Segment Reporting Information [Line Items]
Unaffiliated	2,747		2,750		7,132		7,188
Affiliated	39				40		1
Segment reporting information, revenue for reportable segment, total	2,786		2,750		7,172		7,189
Segment income	333	[1]	408	[1]	636	[1]	874	[1]
Total assets	36,135				36,135				34,166
Total Reportable Segments [Member]
Segment Reporting Information [Line Items]
Unaffiliated	2,747		2,750		7,132		7,188
Affiliated	39				40		1
Segment reporting information, revenue for reportable segment, total	2,786		2,750		7,172		7,189
Segment income	333	[1]	408	[1]	636	[1]	874	[1]
Total assets	36,135				36,135				34,166
Other [Member]
Segment Reporting Information [Line Items]
Unaffiliated	3		3		8		8
Segment reporting information, revenue for reportable segment, total	3		3		8		8
Segment income	(181)	[1],[2]	(117)	[1],[2]	(278)	[1],[2]	(219)	[1],[2]
Total assets	549				549				765
Eliminations [Member]
Segment Reporting Information [Line Items]
Affiliated	(1)				(2)		(1)
Segment reporting information, revenue for reportable segment, total	(1)				(2)		(1)
Reclassifications [Member]
Segment Reporting Information [Line Items]
Total assets	(33)	[3]			(33)	[3]
PEC's Other [Member]
Segment Reporting Information [Line Items]
Segment income	(109)		(5)		(119)		(14)
PEF's Other [Member]
Segment Reporting Information [Line Items]
Segment income	$ (23)		$ (4)		$ (30)		$ (13)

[1] Segment income excludes noncontrolling interests and results of entities classified as discontinued operations.

[2] Segment income includes after-tax costs to achieve the merger with Duke Energy of $132 million and $149 million for the three and nine months ended September 30, 2012, respectively, and $9 million and $27 million for the three and nine months ended September 30, 2011, respectively.

[3] Primarily represents reclassification of federal tax balances in consolidation.