Employee Benefit Plans (Schedule Of Changes In Projected Benefit Obligations And Fair Value Of Plan Assets) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	$ 304		$ 200	$ 400
Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	0		33	158
Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	346		334	129
Progress Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	141		217	95
Progress Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	128		112	34
Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	0		48	45
Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Employer contributions	0		52	46
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	4,880		4,861
Obligation assumed from acquisition	2,850
Service cost	122		96	96
Interest cost on benefit obligation	307		232	248
Actuarial (gain) loss	489		(7)
Plan amendments	(170)		18
Special termination charges				13
Benefits paid	(448)		(320)
Obligation at measurement date	8,030		4,880	4,861
Accumulated benefit obligation	7,843		4,661
Plan assets at prior measurement date	4,741		4,797
Plan assets assumed from acquisition	2,285
Actual return on plan assets	872		64
Employer contributions	304		200
Plan assets at measurement date	7,754		4,741	4,797
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	1,831		1,786
Service cost	35		37	36
Interest cost on benefit obligation	90		85	91
Actuarial (gain) loss	73		20
Plan amendments	(52)		13
Transfers of benefit obligation	176		(5)
Benefits paid	(125)		(105)
Obligation at measurement date	2,028		1,831	1,786
Accumulated benefit obligation	2,028		1,787
Plan assets at prior measurement date	1,820		1,837
Actual return on plan assets	280		60
Transfer of plan assets	176		(5)
Employer contributions			33
Plan assets at measurement date	2,151		1,820	1,837
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	2,729		2,450
Service cost	63		51	46
Interest cost on benefit obligation	127		132	131
Actuarial (gain) loss	166		221
Plan amendments	(64)
Settlement and contractual termination benefit cost			(6)
Benefits paid	(153)		(119)
Obligation at measurement date	2,868		2,729	2,450
Accumulated benefit obligation	2,820		2,692
Plan assets at prior measurement date	2,191		1,891
Actual return on plan assets	263		91
Employer contributions	346		334
Plan assets at measurement date	2,647		2,191	1,891
Qualified Pension Plans [Member] | Progress Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	1,263		1,155
Service cost	25		20	18
Interest cost on benefit obligation	58		61	62
Actuarial (gain) loss	34		81
Plan amendments	(43)
Benefits paid	(73)		(54)
Obligation at measurement date	1,264		1,263	1,155
Accumulated benefit obligation	1,264		1,263
Plan assets at prior measurement date	1,091		884
Actual return on plan assets	130		44
Employer contributions	141		217
Plan assets at measurement date	1,289		1,091	884
Qualified Pension Plans [Member] | Progress Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	1,179		1,043
Service cost	30		24	22
Interest cost on benefit obligation	56		57	56
Actuarial (gain) loss	120		110
Plan amendments	(10)
Benefits paid	(66)		(55)
Obligation at measurement date	1,309		1,179	1,043
Accumulated benefit obligation	1,261		1,142
Plan assets at prior measurement date	969		871
Actual return on plan assets	119		41
Employer contributions	128		112
Plan assets at measurement date	1,150		969	871
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	627		651
Service cost	6		7	7
Interest cost on benefit obligation	31		32	33
Actuarial (gain) loss	68		(9)
Transfers of benefit obligation	(167)		(17)
Benefits paid	(38)		(37)
Obligation at measurement date	527		627	651
Accumulated benefit obligation	501		602
Plan assets at prior measurement date	565		565
Actual return on plan assets	86		6
Transfer of plan assets	(167)		(17)
Employer contributions			48
Plan assets at measurement date	446		565	565
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	613		628
Service cost	9		11	11
Interest cost on benefit obligation	30		30	32
Actuarial (gain) loss	76		(11)
Plan amendments	(1)		(1)
Transfers of benefit obligation			1
Benefits paid	(43)		(45)
Obligation at measurement date	684		613	628
Accumulated benefit obligation	653		582
Plan assets at prior measurement date	582		565
Actual return on plan assets	88		9
Transfer of plan assets			1
Employer contributions			52
Plan assets at measurement date	627		582	565
Non Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	160		167
Obligation assumed from acquisition	172
Service cost	2		1	1
Interest cost on benefit obligation	12		8	9
Actuarial (gain) loss	18		(2)
Plan amendments	(5)
Benefits paid	(24)		(14)
Obligation at measurement date	335		160	167
Accumulated benefit obligation	332		151
Employer contributions	24		14
Non Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	18		21
Interest cost on benefit obligation	1		1	1
Transfers of benefit obligation	1		(1)
Benefits paid	(4)		(3)
Obligation at measurement date	16		18	21
Accumulated benefit obligation	16		17
Employer contributions	4		3
Non Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	177		159
Service cost	2		2	2
Interest cost on benefit obligation	8		9	9
Actuarial (gain) loss	11		17
Plan amendments	(12)
Benefits paid	(10)		(10)
Obligation at measurement date	176		177	159
Accumulated benefit obligation	175		162
Employer contributions	10		10
Non Qualified Pension Plans [Member] | Progress Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	39		33
Service cost	1		1	1
Interest cost on benefit obligation	1		2	2
Actuarial (gain) loss	3		5
Plan amendments	(4)
Benefits paid	(2)		(2)
Obligation at measurement date	38		39	33
Accumulated benefit obligation	36		33
Employer contributions	2		2
Non Qualified Pension Plans [Member] | Progress Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	44		44
Interest cost on benefit obligation	2		2	2
Actuarial (gain) loss	3		1
Plan amendments	(2)
Benefits paid	(2)		(3)
Obligation at measurement date	45		44	44
Accumulated benefit obligation	44		42
Employer contributions	3		3
Non Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date			6
Actuarial (gain) loss			(1)
Benefits paid			(1)
Obligation at measurement date	4		4
Accumulated benefit obligation	4		4
Employer contributions			1
Non Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date			6
Actuarial (gain) loss			(1)
Obligation at measurement date	5		5
Accumulated benefit obligation	5		5
Other Post-Retirement Benefit plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	667		723
Obligation assumed from acquisition	977
Service cost	16		7	7
Interest cost on benefit obligation	56		35	38
Plan participants' contributions	41		32
Actuarial (gain) loss	198		(55)
Plan amendments	(70)
Special termination charges	9
Benefits paid	(105)		(83)
Early retiree reinsurance program subsidy			3
Accrued retiree drug subsidy	5		5
Obligation at measurement date	1,794		667	723
Plan assets at prior measurement date	181		186
Actual return on plan assets	23		4
Employer contributions	58		42
Plan assets at measurement date	198		181	186
Other Post-Retirement Benefit plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	312		326
Service cost	2		2	2
Interest cost on benefit obligation	15		16	17
Plan participants' contributions	18		21
Actuarial (gain) loss	28		(12)
Plan amendments	(33)
Transfers of benefit obligation	9		(1)
Plan transfer			(1)
Special termination charges	1
Benefits paid	(38)		(44)
Early retiree reinsurance program subsidy			2
Accrued retiree drug subsidy	2		3
Obligation at measurement date	316		312	326
Plan assets at prior measurement date	120		125
Actual return on plan assets	12		2
Transfer of plan assets	5
Employer contributions	17		16
Plan assets at measurement date	134		120	125
Other Post-Retirement Benefit plans [Member] | Progress Energy [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	841		733
Service cost	17		11	16
Interest cost on benefit obligation	43		41	45
Plan participants' contributions	13		9
Actuarial (gain) loss	291		98
Plan amendments	(25)
Special termination charges	5
Benefits paid	(61)		(51)
Accrued retiree drug subsidy	4
Obligation at measurement date	1,128		841	733
Plan assets at prior measurement date	37		33
Actual return on plan assets	2		3
Transfer of plan assets	(39)	[1]
Employer contributions	48		43
Plan assets at measurement date			37	33
Other Post-Retirement Benefit plans [Member] | Progress Energy Carolinas [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	407		352
Service cost	8		5	5
Interest cost on benefit obligation	23		20	20
Plan participants' contributions	5		5
Actuarial (gain) loss	205		49
Plan amendments	(16)
Special termination charges	2
Benefits paid	(24)		(24)
Accrued retiree drug subsidy	2
Obligation at measurement date	612		407	352
Employer contributions	19		19
Other Post-Retirement Benefit plans [Member] | Progress Energy Florida [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	368		326
Service cost	7		5	10
Interest cost on benefit obligation	18		18	22
Plan participants' contributions	7		3
Actuarial (gain) loss	49		40
Plan amendments	(6)
Special termination charges	1
Benefits paid	(33)		(24)
Accrued retiree drug subsidy	2
Obligation at measurement date	413		368	326
Plan assets at prior measurement date	37		33
Actual return on plan assets	2		4
Transfer of plan assets	(39)	[1]
Employer contributions	26		21
Plan assets at measurement date			37	33
Other Post-Retirement Benefit plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	61		66
Service cost	1		1	1
Interest cost on benefit obligation	3		3	3
Plan participants' contributions	4		1
Actuarial (gain) loss	3
Transfers of benefit obligation	(16)		(2)
Benefits paid	(8)		(8)
Obligation at measurement date	48		61	66
Plan assets at prior measurement date	9		8
Actual return on plan assets	1
Transfer of plan assets	(3)
Employer contributions	4		8
Plan assets at measurement date	7		9	8
Other Post-Retirement Benefit plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan Disclosure [Line Items]
Obligation at prior measurement date	135		152
Service cost	1		1	1
Interest cost on benefit obligation	6		7	8
Plan participants' contributions	8		4
Actuarial (gain) loss	(2)		(17)
Benefits paid	(13)		(14)
Early retiree reinsurance program subsidy			1
Accrued retiree drug subsidy	1		1
Obligation at measurement date	136		135	152
Plan assets at prior measurement date	14		14
Actual return on plan assets	2
Employer contributions	6		10
Plan assets at measurement date	$ 17		$ 14	$ 14

[1] Progress Energy and Progress Energy Florida amounts reflect assets that did not meet the definition of plan assets. These assets are included in Other within Investments and Other Assets on the Consolidated Balance Sheets.