Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013
Qualified Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 34		$ 42
Interest cost on projected benefit obligation	86		80
Expected return on plan assets	(128)		(137)
Amortization of actuarial loss (gain)	37		61
Amortization of prior service cost (credit)	(4)		(3)
Other	2		2
Net periodic costs	27	[1]	45	[1]
Regulatory asset amortization	3		3
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	10		12
Interest cost on projected benefit obligation	21		20
Expected return on plan assets	(33)		(37)
Amortization of actuarial loss (gain)	9		15
Amortization of prior service cost (credit)	(2)		(2)
Other	1		1
Net periodic costs	6		9
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	10		15
Interest cost on projected benefit obligation	28		29
Expected return on plan assets	(43)		(50)
Amortization of actuarial loss (gain)	17		25
Amortization of prior service cost (credit)	(1)		(1)
Other	1		1
Net periodic costs	12		19
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	5		5
Interest cost on projected benefit obligation	13		13
Expected return on plan assets	(21)		(23)
Amortization of actuarial loss (gain)	8		11
Net periodic costs	5		6
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	5		8
Interest cost on projected benefit obligation	14		13
Expected return on plan assets	(21)		(22)
Amortization of actuarial loss (gain)	8		12
Net periodic costs	6		11
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1		2
Interest cost on projected benefit obligation	5		5
Expected return on plan assets	(7)		(8)
Amortization of actuarial loss (gain)	1		3
Net periodic costs	0	[2]	2	[2]
Regulatory asset amortization	1		2
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	2		3
Interest cost on projected benefit obligation	7		7
Expected return on plan assets	(9)		(11)
Amortization of actuarial loss (gain)	3		6
Net periodic costs	3		5
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	2		7
Interest cost on projected benefit obligation	12		18
Expected return on plan assets	(3)		(3)
Amortization of actuarial loss (gain)	10		13
Amortization of prior service cost (credit)	(31)		(3)
Net periodic costs	(10)	[3]	32	[3]
Regulatory asset amortization	2		2
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost			1
Interest cost on projected benefit obligation	3		3
Expected return on plan assets	(2)		(3)
Amortization of actuarial loss (gain)	1		1
Amortization of prior service cost (credit)	(3)		(2)
Net periodic costs	(1)		0
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1		6
Interest cost on projected benefit obligation	6		11
Amortization of actuarial loss (gain)	10		14
Amortization of prior service cost (credit)	(24)
Net periodic costs	(7)		31
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost			3
Interest cost on projected benefit obligation	3		6
Amortization of actuarial loss (gain)	7		9
Amortization of prior service cost (credit)	(18)
Net periodic costs	(8)		18
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1		2
Interest cost on projected benefit obligation	3		4
Amortization of actuarial loss (gain)	2		4
Amortization of prior service cost (credit)	(5)
Net periodic costs	1		10
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Net periodic costs	0	[4]	0	[4]
Regulatory asset amortization	1		1
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost			0
Interest cost on projected benefit obligation	1		1
Amortization of actuarial loss (gain)			(1)
Net periodic costs	$ 1		$ 0

[1] Duke Energy amounts exclude $3 million for each of the three months ended March 31, 2014 and 2013, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy’s merger with Cinergy.

[2] Duke Energy Ohio amounts exclude $1 million and $2 million for the three months ended March 31, 2014 and 2013, respectively, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy’s merger with Cinergy.

[3] Duke Energy amounts exclude $2 million for each of the three months ended March 31, 2014 and 2013, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy’s merger with Cinergy.

[4] Duke Energy Ohio amounts exclude $1 million for each of the three months ended March 31, 2014 and 2013, of regulatory asset amortization resulting from purchase accounting adjustments associated with Duke Energy’s merger with Cinergy.