Employee Benefit Plans (Components Of Net Periodic Pension Costs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Pension Plans Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 122		$ 96		$ 96
Interest cost on benefit obligation	307		232		248
Expected return on plan assets	(472)		(384)		(378)
Amortization of prior service cost (credit)	10		6		5
Amortization of loss (gain)	144		77		50
Special termination charges					13
Other	6		18		18
Net periodic costs	117	[1]	45	[1]	52	[1]
Regulatory asset amortization	14		14		16
Pension Plans Defined Benefit [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	35		37		36
Interest cost on benefit obligation	90		85		91
Expected return on plan assets	(146)		(150)		(147)
Amortization of prior service cost (credit)	1		1		1
Amortization of loss (gain)	45		37		27
Other	2		7		8
Net periodic costs	27		17		16
Pension Plans Defined Benefit [Member] | Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	63		51		46
Interest cost on benefit obligation	127		132		131
Expected return on plan assets	(188)		(182)		(157)
Amortization of prior service cost (credit)	9		7		7
Amortization of loss (gain)	93		66		49
Other	2		0		0
Net periodic costs	106		74		76
Pension Plans Defined Benefit [Member] | Progress Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	25		20		18
Interest cost on benefit obligation	58		61		62
Expected return on plan assets	(96)		(91)		(77)
Amortization of prior service cost (credit)	8		6		6
Amortization of loss (gain)	37		25		16
Other	1		0		0
Net periodic costs	33		21		25
Pension Plans Defined Benefit [Member] | Progress Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	30		24		22
Interest cost on benefit obligation	56		57		56
Expected return on plan assets	(81)		(78)		(68)
Amortization of prior service cost (credit)	(1)		0		0
Amortization of loss (gain)	48		33		31
Other	1		0		0
Net periodic costs	53		36		41
Pension Plans Defined Benefit [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	6		7		7
Interest cost on benefit obligation	31		32		33
Expected return on plan assets	(45)		(44)		(44)
Amortization of prior service cost (credit)	1		1		1
Amortization of loss (gain)	10		7		4
Other	0		2		2
Net periodic costs	3	[2]	5	[2]	3	[2]
Regulatory asset amortization	6		7		7
Pension Plans Defined Benefit [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	9		11		11
Interest cost on benefit obligation	30		30		32
Expected return on plan assets	(46)		(45)		(45)
Amortization of prior service cost (credit)	1		2		2
Amortization of loss (gain)	15		14		12
Other	0		2		2
Net periodic costs	9		14		14
Non Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2		1		1
Interest cost on benefit obligation	12		8		9
Amortization of prior service cost (credit)	1		2		2
Amortization of loss (gain)	4
Net periodic costs	19		11		12
Non Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost on benefit obligation	1		1		1
Amortization of prior service cost (credit)					1
Net periodic costs	1		1		2
Non Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2		2		2
Interest cost on benefit obligation	8		9		9
Amortization of prior service cost (credit)	(1)
Amortization of loss (gain)	5		3		2
Net periodic costs	14		14		13
Non Qualified Pension Plans [Member] | Progress Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1		1		1
Interest cost on benefit obligation	1		2		2
Amortization of loss (gain)	1
Net periodic costs	3		3		3
Non Qualified Pension Plans [Member] | Progress Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Interest cost on benefit obligation	2		2		2
Amortization of loss (gain)			1		1
Net periodic costs	2		3		3
Other Postretirement Benefit Plans Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	16		7		7
Interest cost on benefit obligation	56		35		38
Expected return on plan assets	(17)		(15)		(15)
Amortization of prior service cost (credit)	(8)		(8)		(8)
Amortization of net transition liability	10		10		11
Amortization of loss (gain)	14		(3)		(5)
Special termination charges	9
Net periodic costs	80	[3]	26	[3]	28	[3]
Regulatory asset amortization	9		8		9
Other Postretirement Benefit Plans Defined Benefit [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	2		2		2
Interest cost on benefit obligation	15		16		17
Expected return on plan assets	(10)		(10)		(10)
Amortization of prior service cost (credit)	(5)		(5)		(5)
Amortization of net transition liability	7		9		9
Amortization of loss (gain)	3		2		3
Special termination charges	1
Net periodic costs	13		14		16
Other Postretirement Benefit Plans Defined Benefit [Member] | Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	17		11		16
Interest cost on benefit obligation	43		41		45
Expected return on plan assets	(2)		(2)		(4)
Amortization of net transition liability	4		5		5
Amortization of loss (gain)	35		12		13
Special termination charges	5
Net periodic costs	102		67		75
Other Postretirement Benefit Plans Defined Benefit [Member] | Progress Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	8		5		5
Interest cost on benefit obligation	23		20		20
Expected return on plan assets					(2)
Amortization of net transition liability			1		1
Amortization of loss (gain)	20		5		4
Special termination charges	2
Net periodic costs	53		31		28
Other Postretirement Benefit Plans Defined Benefit [Member] | Progress Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	7		5		10
Interest cost on benefit obligation	18		18		22
Expected return on plan assets	(2)		(2)		(2)
Amortization of net transition liability	3		4		4
Amortization of loss (gain)	12		7		9
Special termination charges	1
Net periodic costs	39		32		43
Other Postretirement Benefit Plans Defined Benefit [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1		1		1
Interest cost on benefit obligation	3		3		3
Expected return on plan assets	(1)		(1)		(1)
Amortization of prior service cost (credit)	(1)		(1)		(1)
Amortization of loss (gain)	(2)		(2)		(2)
Net periodic costs	0	[4]	0	[4]	0	[4]
Regulatory asset amortization	2		2		2
Other Postretirement Benefit Plans Defined Benefit [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	1		1		1
Interest cost on benefit obligation	6		7		8
Expected return on plan assets	(1)		(1)		(1)
Amortization of loss (gain)			2		1
Net periodic costs	$ 6		$ 9		$ 9

[1] Duke Energy amounts exclude $14 million, $14 million and $16 million for the years ended December 31, 2012, 2011, and 2010, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy’s merger with Cinergy in April 2006.

[2] Duke Energy Ohio amounts exclude $6 million, $7 million and $7 million for the years ended December 31, 2012, 2011, and 2010, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy’s merger with Cinergy in April 2006.

[3] Duke Energy amounts exclude $9 million, $8 million and $9 million for the years ended December 31, 2012, 2011 and 2010, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy’s merger with Cinergy in April 2006.

[4] Duke Energy Ohio amounts exclude $2 million for each of the years ended December 31, 2012, 2011 and 2010, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy’s merger with Cinergy in April 2006.