Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
Qualified Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 167		$ 122		$ 96
Interest cost on projected benefit obligation	320		307		232
Expected return on plan assets	(549)		(472)		(384)
Amortization of actuarial loss (gain)	244		144		77
Amortization of prior service cost (credit)	(11)		10		6
Other	7		6		18
Net periodic costs	178	[1],[2]	117	[1],[2]	45	[1],[2]
Regulatory asset amortization	12		14		14
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	49		35		37
Interest cost on projected benefit obligation	80		90		85
Expected return on plan assets	(148)		(146)		(150)
Amortization of actuarial loss (gain)	60		45		37
Amortization of prior service cost (credit)	(6)		1		1
Other	2		2		7
Net periodic costs	37	[1],[2]	27	[1],[2]	17	[1],[2]
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	60		63		51
Interest cost on projected benefit obligation	116		127		132
Expected return on plan assets	(199)		(188)		(182)
Amortization of actuarial loss (gain)	101		93		66
Amortization of prior service cost (credit)	(4)		9		7
Other	2		2
Net periodic costs	76	[1],[2]	106	[1],[2]	74	[1],[2]
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	22		25		20
Interest cost on projected benefit obligation	50		58		61
Expected return on plan assets	(94)		(96)		(91)
Amortization of actuarial loss (gain)	46		37		25
Amortization of prior service cost (credit)	(1)		8		6
Other	1		1
Net periodic costs	24	[1],[2]	33	[1],[2]	21	[1],[2]
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	30		30		24
Interest cost on projected benefit obligation	53		56		57
Expected return on plan assets	(87)		(81)		(78)
Amortization of actuarial loss (gain)	49		48		33
Amortization of prior service cost (credit)	(2)		(1)
Other	1		1
Net periodic costs	44	[1],[2]	53	[1],[2]	36	[1],[2]
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	6		6		7
Interest cost on projected benefit obligation	21		31		32
Expected return on plan assets	(31)		(45)		(44)
Amortization of actuarial loss (gain)	13		10		7
Amortization of prior service cost (credit)			1		1
Other					2
Net periodic costs	9	[1],[2]	3	[1],[2]	5	[1],[2]
Regulatory asset amortization	6		6		7
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	11		9		11
Interest cost on projected benefit obligation	28		30		30
Expected return on plan assets	(46)		(46)		(45)
Amortization of actuarial loss (gain)	24		15		14
Amortization of prior service cost (credit)	1		1		2
Other	1				2
Net periodic costs	19	[1],[2]	9	[1],[2]	14	[1],[2]
Non-Qualified Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	3		2		1
Interest cost on projected benefit obligation	13		12		8
Amortization of actuarial loss (gain)	5		4
Amortization of prior service cost (credit)	(1)		1		2
Net periodic costs	20		19		11
Non-Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	1		1		1
Net periodic costs	1		1		1
Non-Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1		2		2
Interest cost on projected benefit obligation	7		8		9
Amortization of actuarial loss (gain)	3		5		3
Amortization of prior service cost (credit)	(1)		(1)
Net periodic costs	10		14		14
Non-Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1		1		1
Interest cost on projected benefit obligation	1		1		2
Amortization of actuarial loss (gain)	1		1
Net periodic costs	3		3		3
Non-Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	1		2		2
Amortization of actuarial loss (gain)	1				1
Net periodic costs	2		2		3
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	24		16		7
Interest cost on projected benefit obligation	68		56		35
Expected return on plan assets	(14)		(17)		(15)
Amortization of actuarial loss (gain)	52		14		(3)
Amortization of prior service cost (credit)	(41)		(8)		(8)
Amortization of net transition liability			10		10
Special termination benefit cost			9
Net periodic costs	89	[3],[4]	80	[3],[4]	26	[3],[4]
Regulatory asset amortization	8		9		8
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	2		2		2
Interest cost on projected benefit obligation	13		15		16
Expected return on plan assets	(11)		(10)		(10)
Amortization of actuarial loss (gain)	3		3		2
Amortization of prior service cost (credit)	(7)		(5)		(5)
Amortization of net transition liability			7		9
Special termination benefit cost			1
Net periodic costs	0	[3],[4]	13	[3],[4]	14	[3],[4]
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	18		17		11
Interest cost on projected benefit obligation	41		43		41
Expected return on plan assets			(2)		(2)
Amortization of actuarial loss (gain)	57		35		12
Amortization of prior service cost (credit)	(30)
Amortization of net transition liability			4		5
Special termination benefit cost			5
Net periodic costs	86	[3],[4]	102	[3],[4]	67	[3],[4]
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	9		8		5
Interest cost on projected benefit obligation	22		23		20
Amortization of actuarial loss (gain)	34		20		5
Amortization of prior service cost (credit)	(20)
Amortization of net transition liability					1
Special termination benefit cost	0		2
Net periodic costs	45	[3],[4]	53	[3],[4]	31	[3],[4]
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	7		7		5
Interest cost on projected benefit obligation	16		18		18
Expected return on plan assets			(2)		(2)
Amortization of actuarial loss (gain)	16		12		7
Amortization of prior service cost (credit)	(6)
Amortization of net transition liability			3		4
Special termination benefit cost			1
Net periodic costs	33	[3],[4]	39	[3],[4]	32	[3],[4]
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1		1		1
Interest cost on projected benefit obligation	2		3		3
Expected return on plan assets	(1)		(1)		(1)
Amortization of actuarial loss (gain)	(1)		(2)		(2)
Amortization of prior service cost (credit)	(1)		(1)		(1)
Net periodic costs	0	[3],[4]	0	[3],[4]	0	[3],[4]
Regulatory asset amortization	2		2		2
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1		1		1
Interest cost on projected benefit obligation	5		6		7
Expected return on plan assets	(1)		(1)		(1)
Amortization of actuarial loss (gain)	1				2
Net periodic costs	$ 6	[3],[4]	$ 6	[3],[4]	$ 9	[3],[4]

[1] Duke Energy amounts exclude $12 million, $14 million and $14 million for the years ended December 2013, 2012, and 2011, 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, $6 million and $7 million for the years ended December 2013, 2012, and 2011, 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 $8 million, $9 million and $8 million for the years ended December 31, 2013, 2012 and 2011, 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, 2013, 2012 and 2011, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy’s merger with Cinergy in April 2006.