Employee Benefit Plans (Projected Benefit Obligations Reconciliation of Funded Status to Net Amount Recognized) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012		Dec. 31, 2011
Qualified Pension Plans [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	$ 8,030	$ 4,880
Obligation assumed from acquisition		2,850
Service cost	167	122		96
Interest cost on projected benefit obligation	320	307		232
Actuarial (gains) losses	(399)	489
Plan amendments	(41)	(170)
Benefits paid	(567)	(448)
Obligation at measurement date	7,510	8,030		4,880
Accumulated benefit obligation at measurement date	7,361	7,843
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	7,754	4,741
Assets received from acquisition		2,285
Actual return on plan assets	705	872
Benefits paid	(567)	(448)
Employer contributions	250	304		200
Plan assets at measurement date	8,142	7,754		4,741
Funded status of plan	632	(276)
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	2,028	1,831
Service cost	49	35		37
Interest cost on projected benefit obligation	80	90		85
Actuarial (gains) losses	(73)	73
Transfers of benefit obligation	(26)	176
Plan amendments	(13)	(52)
Benefits paid	(170)	(125)
Obligation at measurement date	1,875	2,028		1,831
Accumulated benefit obligation at measurement date	1,875	2,028
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	2,151	1,820
Actual return on plan assets	207	280
Benefits paid	(170)	(125)
Transfer of plan assets	(26)	176
Employer contributions				33
Plan assets at measurement date	2,162	2,151		1,820
Funded status of plan	287	123
Qualified Pension Plans [Member] | Progress Energy [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	2,868	2,729
Service cost	60	63		51
Interest cost on projected benefit obligation	116	127		132
Actuarial (gains) losses	(118)	166
Transfers of benefit obligation	(7)
Plan amendments	(19)	(64)
Benefits paid	(161)	(153)
Obligation at measurement date	2,739	2,868		2,729
Accumulated benefit obligation at measurement date	2,698	2,820
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	2,647	2,191
Actual return on plan assets	215	263
Benefits paid	(161)	(153)
Transfer of plan assets	(7)
Employer contributions	250	346		334
Plan assets at measurement date	2,944	2,647		2,191
Funded status of plan	205	(221)
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	1,264	1,263
Service cost	22	25		20
Interest cost on projected benefit obligation	50	58		61
Actuarial (gains) losses	(26)	34
Transfers of benefit obligation	(45)
Plan amendments	(8)	(43)
Benefits paid	(85)	(73)
Obligation at measurement date	1,172	1,264		1,263
Accumulated benefit obligation at measurement date	1,172	1,264
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	1,289	1,091
Actual return on plan assets	108	130
Benefits paid	(85)	(73)
Transfer of plan assets	(45)
Employer contributions	63	141		217
Plan assets at measurement date	1,330	1,289		1,091
Funded status of plan	158	25
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	1,309	1,179
Service cost	30	30		24
Interest cost on projected benefit obligation	53	56		57
Actuarial (gains) losses	(75)	120
Transfers of benefit obligation	(17)
Plan amendments	(7)	(10)
Benefits paid	(60)	(66)
Obligation at measurement date	1,233	1,309		1,179
Accumulated benefit obligation at measurement date	1,192	1,261
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	1,150	969
Actual return on plan assets	93	119
Benefits paid	(60)	(66)
Transfer of plan assets	(17)
Employer contributions	133	128		112
Plan assets at measurement date	1,299	1,150		969
Funded status of plan	66	(159)
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	527	627
Service cost	6	6		7
Interest cost on projected benefit obligation	21	31		32
Actuarial (gains) losses	(71)	68
Transfers of benefit obligation	(2)	(167)
Benefits paid	(39)	(38)
Obligation at measurement date	442	527		627
Accumulated benefit obligation at measurement date	429	501
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	446	565
Actual return on plan assets	43	86
Benefits paid	(39)	(38)
Transfer of plan assets	(2)	(167)
Employer contributions				48
Plan assets at measurement date	448	446		565
Funded status of plan	6	(81)
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	684	613
Service cost	11	9		11
Interest cost on projected benefit obligation	28	30		30
Actuarial (gains) losses	(56)	76
Transfers of benefit obligation	(2)
Plan amendments		(1)
Benefits paid	(33)	(43)
Obligation at measurement date	632	684		613
Accumulated benefit obligation at measurement date	608	653
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	627	582
Actual return on plan assets	62	88
Benefits paid	(33)	(43)
Transfer of plan assets	(2)
Employer contributions				52
Plan assets at measurement date	654	627		582
Funded status of plan	22	(57)
Non Qualified Pension Plans [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	335	160
Obligation assumed from acquisition		172
Service cost	3	2		1
Interest cost on projected benefit obligation	13	12		8
Actuarial (gains) losses	(15)	18
Settlements	(5)
Plan amendments	(1)	(5)
Benefits paid	(26)	(24)
Obligation at measurement date	304	335		160
Accumulated benefit obligation at measurement date	302	332
Change in Fair Value of Plan Assets [Rollforward]
Benefits paid	(26)	(24)
Employer contributions	26	24
Non Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	16	18
Interest cost on projected benefit obligation	1	1		1
Actuarial (gains) losses	1
Transfers of benefit obligation		1
Benefits paid	(3)	(4)
Obligation at measurement date	15	16		18
Accumulated benefit obligation at measurement date	15	16
Change in Fair Value of Plan Assets [Rollforward]
Benefits paid	(3)	(4)
Employer contributions	3	4
Non Qualified Pension Plans [Member] | Progress Energy [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	176	177
Service cost	1	2		2
Interest cost on projected benefit obligation	7	8		9
Actuarial (gains) losses	(11)	11
Transfers of benefit obligation	(21)
Plan amendments		(12)
Benefits paid	(12)	(10)
Obligation at measurement date	140	176		177
Accumulated benefit obligation at measurement date	140	175
Change in Fair Value of Plan Assets [Rollforward]
Benefits paid	(12)	(10)
Employer contributions	12	10
Non Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	38	39
Service cost	1	1		1
Interest cost on projected benefit obligation	1	1		2
Actuarial (gains) losses	(3)	3
Plan amendments		(4)
Benefits paid	(3)	(2)
Obligation at measurement date	34	38		39
Accumulated benefit obligation at measurement date	34	36
Change in Fair Value of Plan Assets [Rollforward]
Benefits paid	(3)	(2)
Employer contributions	3	2
Non Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	45	44
Interest cost on projected benefit obligation	1	2		2
Actuarial (gains) losses	(3)	3
Plan amendments		(2)
Benefits paid	(4)	(2)
Obligation at measurement date	39	45		44
Accumulated benefit obligation at measurement date	39	44
Change in Fair Value of Plan Assets [Rollforward]
Benefits paid	(4)	(2)
Employer contributions	4	3
Non Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	4
Actuarial (gains) losses	(1)
Obligation at measurement date	3			4
Accumulated benefit obligation at measurement date	3	4
Non Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at measurement date	5	5		5
Accumulated benefit obligation at measurement date	5	5
Other Post-Retirement Benefit Plans [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	1,794	667
Obligation assumed from acquisition		977
Service cost	24	16		7
Interest cost on projected benefit obligation	68	56		35
Plan participants' contributions	47	41
Actuarial (gains) losses	(227)	198
Plan amendments	(476)	(70)
Special termination benefit cost		9
Benefits paid	(132)	(105)
Accrued retiree drug subsidy	8	5
Obligation at measurement date	1,106	1,794		667
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	198	181
Actual return on plan assets	18	23
Benefits paid	(132)	(105)
Employer contributions	83	58
Plan participants' contributions	47	41
Plan assets at measurement date	214	198		181
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	316	312
Service cost	2	2		2
Interest cost on projected benefit obligation	13	15		16
Plan participants' contributions	15	18
Actuarial (gains) losses	(32)	28
Transfers of benefit obligation		9
Plan amendments	(16)	(33)
Special termination benefit cost		1
Benefits paid	(36)	(38)
Accrued retiree drug subsidy	3	2
Obligation at measurement date	265	316		312
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	134	120
Actual return on plan assets	13	12
Benefits paid	(36)	(38)
Transfer of plan assets	(1)	5
Employer contributions	18	17
Plan participants' contributions	15	18
Plan assets at measurement date	143	134		120
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	1,128	841
Service cost	18	17		11
Interest cost on projected benefit obligation	41	43		41
Plan participants' contributions	14	13
Actuarial (gains) losses	(156)	291
Transfers of benefit obligation	(1)
Plan amendments	(455)	(25)
Special termination benefit cost		5
Benefits paid	(60)	(61)
Accrued retiree drug subsidy	4	4
Obligation at measurement date	533	1,128		841
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date		37
Actual return on plan assets		2
Benefits paid	(60)	(61)
Transfer of plan assets	0	(39)	[1]
Employer contributions	46	48
Plan participants' contributions	14	13
Plan assets at measurement date				37
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	612	407
Service cost	9	8		5
Interest cost on projected benefit obligation	22	23		20
Plan participants' contributions	6	5
Actuarial (gains) losses	(73)	205
Transfers of benefit obligation	(8)
Plan amendments	(311)	(16)
Special termination benefit cost	0	2
Benefits paid	(26)	(24)
Accrued retiree drug subsidy	2	2
Obligation at measurement date	233	612		407
Change in Fair Value of Plan Assets [Rollforward]
Benefits paid	(26)	(24)
Employer contributions	20	19
Plan participants' contributions	6	5
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	413	368
Service cost	7	7		5
Interest cost on projected benefit obligation	16	18		18
Plan participants' contributions	7	7
Actuarial (gains) losses	(70)	49
Plan amendments	(91)	(6)
Special termination benefit cost		1
Benefits paid	(31)	(33)
Accrued retiree drug subsidy	2	2
Obligation at measurement date	253	413		368
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date		37
Actual return on plan assets		2
Benefits paid	(31)	(33)
Transfer of plan assets	0	(39)	[1]
Employer contributions	24	26
Plan participants' contributions	7	7
Plan assets at measurement date				37
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	48	61
Service cost	1	1		1
Interest cost on projected benefit obligation	2	3		3
Plan participants' contributions	3	4
Actuarial (gains) losses	(6)	3
Transfers of benefit obligation		(16)
Benefits paid	(6)	(8)
Obligation at measurement date	42	48		61
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	7	9
Actual return on plan assets	2	1
Benefits paid	(6)	(8)
Transfer of plan assets	0	(3)
Employer contributions	2	4
Plan participants' contributions	3	4
Plan assets at measurement date	8	7		9
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Change in Projected Benefit Obligation [Rollforward]
Obligation at prior measurement date	136	135
Service cost	1	1		1
Interest cost on projected benefit obligation	5	6		7
Plan participants' contributions	3	8
Actuarial (gains) losses	(12)	(2)
Plan amendments	(3)
Benefits paid	(14)	(13)
Accrued retiree drug subsidy	2	1
Obligation at measurement date	118	136		135
Change in Fair Value of Plan Assets [Rollforward]
Plan assets at prior measurement date	17	14
Actual return on plan assets	2	2
Benefits paid	(14)	(13)
Employer contributions	10	6
Plan participants' contributions	3	8
Plan assets at measurement date	$ 18	$ 17		$ 14

[1] Progress Energy and Duke 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.