Employee Benefit Plans (Components of Net Periodic Pension Costs) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Qualified Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of Regulatory Asset	$ 8	$ 9	$ 10
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	147	159	135
Interest cost on projected benefit obligation	335	324	344
Expected return on plan assets	(519)	(516)	(511)
Amortization of actuarial loss (gain)	134	166	150
Amortization of prior service cost (credit)	(17)	(15)	(15)
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements	3
Other	8	8	8
Net periodic costs	91	126	111
Qualified Pension Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	48	50	41
Interest cost on projected benefit obligation	86	83	85
Expected return on plan assets	(142)	(139)	(132)
Amortization of actuarial loss (gain)	33	39	36
Amortization of prior service cost (credit)	(8)	(7)	(8)
Other	2	2	2
Net periodic costs	19	28	24
Qualified Pension Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	42	44	40
Interest cost on projected benefit obligation	106	104	112
Expected return on plan assets	(168)	(171)	(173)
Amortization of actuarial loss (gain)	51	65	68
Amortization of prior service cost (credit)	(3)	(3)	(3)
Other	3	3	3
Net periodic costs	31	42	47
Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	24	23	21
Interest cost on projected benefit obligation	49	48	54
Expected return on plan assets	(82)	(79)	(85)
Amortization of actuarial loss (gain)	23	33	32
Amortization of prior service cost (credit)	(2)	(2)	(2)
Other	1	1	1
Net periodic costs	13	24	21
Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	19	20	20
Interest cost on projected benefit obligation	55	54	57
Expected return on plan assets	(84)	(87)	(85)
Amortization of actuarial loss (gain)	29	31	32
Amortization of prior service cost (credit)	(1)	(1)	(1)
Other	1	1	1
Net periodic costs	19	18	24
Qualified Pension Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of Regulatory Asset	4	4	5
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	4	4	4
Interest cost on projected benefit obligation	19	18	20
Expected return on plan assets	(27)	(26)	(27)
Amortization of actuarial loss (gain)	4	7	4
Other	1
Net periodic costs	1	3	1
Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	9	10	9
Interest cost on projected benefit obligation	28	27	29
Expected return on plan assets	(42)	(42)	(41)
Amortization of actuarial loss (gain)	11	13	13
Amortization of prior service cost (credit)	(1)	1
Other	1	1	1
Net periodic costs	6	10	11
Non-Qualified Pension Plans [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	2	3	3
Interest cost on projected benefit obligation	14	13	14
Amortization of actuarial loss (gain)	8	6	3
Amortization of prior service cost (credit)	(1)	(1)	(1)
Net periodic costs	23	21	19
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
Amortization of actuarial loss (gain)	1
Net periodic costs	2	1	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	5	4	5
Amortization of actuarial loss (gain)	1	2	2
Amortization of prior service cost (credit)		(1)	(1)
Net periodic costs	6	6	7
Non-Qualified Pension Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost			1
Interest cost on projected benefit obligation	1	1	1
Amortization of actuarial loss (gain)	1	1
Net periodic costs	2	2	2
Non-Qualified Pension Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	2	2	2
Amortization of actuarial loss (gain)	1	2
Net periodic costs	3	4	2
Non-Qualified Pension Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Amortization of actuarial loss (gain)		1
Net periodic costs		1
Other Post-Retirement Benefit Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of Regulatory Asset	8	10	9
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	3	6	10
Interest cost on projected benefit obligation	35	36	49
Expected return on plan assets	(12)	(13)	(13)
Amortization of actuarial loss (gain)	6	16	39
Amortization of prior service cost (credit)	(141)	(140)	(125)
Net periodic costs	(109)	(95)	(40)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Carolinas [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1	2
Interest cost on projected benefit obligation	8	9	12
Expected return on plan assets	(8)	(8)	(9)
Amortization of actuarial loss (gain)	(3)	(2)	3
Amortization of prior service cost (credit)	(14)	(14)	(11)
Net periodic costs	(16)	(14)	(3)
Other Post-Retirement Benefit Plans [Member] | Progress Energy [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1	4
Interest cost on projected benefit obligation	15	15	22
Amortization of actuarial loss (gain)	22	28	42
Amortization of prior service cost (credit)	(103)	(102)	(95)
Net periodic costs	(65)	(58)	(27)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Progress [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost		1	1
Interest cost on projected benefit obligation	8	8	11
Amortization of actuarial loss (gain)	13	18	31
Amortization of prior service cost (credit)	(68)	(68)	(73)
Net periodic costs	(47)	(41)	(30)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Florida [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	1	1	3
Interest cost on projected benefit obligation	7	7	12
Amortization of actuarial loss (gain)	9	10	10
Amortization of prior service cost (credit)	(35)	(35)	(21)
Net periodic costs	(18)	(17)	4
Other Post-Retirement Benefit Plans [Member] | Duke Energy Ohio [Member]
Defined Benefit Plan Disclosure [Line Items]
Amortization of Regulatory Asset	2	3	2
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost on projected benefit obligation	1	2	2
Expected return on plan assets		(1)
Amortization of actuarial loss (gain)	(2)	(2)	(2)
Net periodic costs	(1)	(1)
Other Post-Retirement Benefit Plans [Member] | Duke Energy Indiana [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost		1	1
Interest cost on projected benefit obligation	4	4	5
Expected return on plan assets	(1)	(1)	(1)
Amortization of actuarial loss (gain)	(1)	(2)
Amortization of prior service cost (credit)	(1)
Net periodic costs	$ 1	$ 2	$ 5