Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Qualified Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	$ 34	$ 42	$ 68	$ 84
Interest cost on projected benefit obligation	86	80	172	160
Expected return on plan assets	(127)	(137)	(255)	(274)
Amortization of actuarial loss (gain)	37	61	74	122
Amortization of prior service cost (credit)	(3)	(3)	(7)	(6)
Other	1	1	3	3
Net periodic costs	28	44	55	89
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	11	13	21	25
Interest cost on projected benefit obligation	21	20	42	40
Expected return on plan assets	(33)	(37)	(66)	(74)
Amortization of actuarial loss (gain)	9	15	18	30
Amortization of prior service cost (credit)	(2)	(1)	(4)	(3)
Other			1	1
Net periodic costs	6	10	12	19
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	10	15	20	30
Interest cost on projected benefit obligation	28	29	56	58
Expected return on plan assets	(43)	(49)	(86)	(99)
Amortization of actuarial loss (gain)	17	25	34	50
Amortization of prior service cost (credit)	(1)	(1)	(2)	(2)
Other			1	1
Net periodic costs	11	19	23	38
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	5	6	10	11
Interest cost on projected benefit obligation	14	12	27	25
Expected return on plan assets	(22)	(24)	(43)	(47)
Amortization of actuarial loss (gain)	8	12	16	23
Amortization of prior service cost (credit)	(1)		(1)
Other	1		1
Net periodic costs	5	6	10	12
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	5	7	10	15
Interest cost on projected benefit obligation	15	14	29	27
Expected return on plan assets	(22)	(22)	(43)	(44)
Amortization of actuarial loss (gain)	8	13	16	25
Amortization of prior service cost (credit)	(1)	(1)	(1)	(1)
Other	1		1
Net periodic costs	6	11	12	22
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1	2	3
Interest cost on projected benefit obligation	5	6	10	11
Expected return on plan assets	(6)	(7)	(13)	(15)
Amortization of actuarial loss (gain)	1	3	2	6
Amortization of prior service cost (credit)
Other
Net periodic costs	1	3	1	5
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	2	3	4	6
Interest cost on projected benefit obligation	8	7	15	14
Expected return on plan assets	(11)	(11)	(20)	(22)
Amortization of actuarial loss (gain)	3	5	6	11
Amortization of prior service cost (credit)
Other
Net periodic costs	2	4	5	9
Non-Qualified Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1	1	1
Interest cost on projected benefit obligation	3	3	7	7
Amortization of actuarial loss (gain)	1	1	1	3
Amortization of prior service cost (credit)				(1)
Net periodic costs	5	5	9	10
Non-Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost
Interest cost on projected benefit obligation		1		1
Amortization of actuarial loss (gain)
Amortization of prior service cost (credit)
Net periodic costs	0	1	0	1
Non-Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1		1
Interest cost on projected benefit obligation		2	2	4
Amortization of actuarial loss (gain)	1	1	1	2
Amortization of prior service cost (credit)				(1)
Net periodic costs	2	3	4	5
Non-Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost
Interest cost on projected benefit obligation		1	1	1
Amortization of actuarial loss (gain)
Amortization of prior service cost (credit)
Net periodic costs	0	1	1	1
Non-Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost
Interest cost on projected benefit obligation	1	1	1	1
Amortization of actuarial loss (gain)
Amortization of prior service cost (credit)
Net periodic costs	1	1	1	1
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	3	7	5	14
Interest cost on projected benefit obligation	13	18	25	36
Expected return on plan assets	(3)	(4)	(6)	(7)
Amortization of actuarial loss (gain)	10	13	20	26
Amortization of prior service cost (credit)	(32)	(3)	(63)	(6)
Net periodic costs	(9)	31	(19)	63
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1		1	1
Interest cost on projected benefit obligation	3	3	6	6
Expected return on plan assets	(2)	(2)	(4)	(5)
Amortization of actuarial loss (gain)		1	1	2
Amortization of prior service cost (credit)	(2)	(2)	(5)	(4)
Net periodic costs	0	0	(1)	0
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	5	2	11
Interest cost on projected benefit obligation	5	12	11	23
Expected return on plan assets
Amortization of actuarial loss (gain)	11	15	21	29
Amortization of prior service cost (credit)	(23)	(1)	(47)	(1)
Net periodic costs	(6)	31	(13)	62
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	3	1	6
Interest cost on projected benefit obligation	2	6	5	12
Expected return on plan assets
Amortization of actuarial loss (gain)	8	9	15	18
Amortization of prior service cost (credit)	(18)	(1)	(36)	(1)
Net periodic costs	(7)	17	(15)	35
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	2	2	4
Interest cost on projected benefit obligation	3	4	6	8
Expected return on plan assets
Amortization of actuarial loss (gain)	3	4	5	8
Amortization of prior service cost (credit)	(6)		(11)
Net periodic costs	1	10	2	20
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost
Interest cost on projected benefit obligation	1	1	1	1
Expected return on plan assets
Amortization of actuarial loss (gain)	(1)	(1)	(1)	(1)
Amortization of prior service cost (credit)
Net periodic costs	0	0	0	0
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost
Interest cost on projected benefit obligation	2	2	3	3
Expected return on plan assets	(1)		(1)
Amortization of actuarial loss (gain)
Amortization of prior service cost (credit)
Net periodic costs	$ 1	$ 2	$ 2	$ 3