Commitments and Contingencies (Future Minimum Payments for Operating and Capital Leases) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Operating Leased Assets
Rental expense on operating leases	$ 318	$ 355	$ 321
Operating Leases, Future Minimum Payments Due [Abstract]
2016	219
2017	182
2018	161
2019	146
2020	127
Thereafter	864
Total future minimum lease payments	1,699
Capital Leases, Future Minimum Payments Due [Abstract]
2016	173
2017	171
2018	180
2019	178
2020	182
Thereafter	1,176
Minimum annual payments	2,060
Less amount representing interest	(724)
Total	1,336
Duke Energy Carolinas [Member]
Operating Leased Assets
Rental expense on operating leases	41	41	39
Operating Leases, Future Minimum Payments Due [Abstract]
2016	41
2017	33
2018	24
2019	21
2020	16
Thereafter	51
Total future minimum lease payments	186
Capital Leases, Future Minimum Payments Due [Abstract]
2016	6
2017	6
2018	6
2019	6
2020	5
Thereafter	30
Minimum annual payments	59
Less amount representing interest	(35)
Total	24
Progress Energy [Member]
Operating Leased Assets
Rental expense on operating leases	230	257	225
Operating Leases, Future Minimum Payments Due [Abstract]
2016	132
2017	111
2018	108
2019	102
2020	93
Thereafter	622
Total future minimum lease payments	1,168
Capital Leases, Future Minimum Payments Due [Abstract]
2016	46
2017	46
2018	46
2019	45
2020	46
Thereafter	367
Minimum annual payments	596
Less amount representing interest	(295)
Total	301
Duke Energy Progress [Member]
Operating Leased Assets
Rental expense on operating leases	149	161	153
Operating Leases, Future Minimum Payments Due [Abstract]
2016	66
2017	63
2018	61
2019	56
2020	48
Thereafter	365
Total future minimum lease payments	659
Capital Leases, Future Minimum Payments Due [Abstract]
2016	20
2017	21
2018	21
2019	22
2020	21
Thereafter	272
Minimum annual payments	377
Less amount representing interest	(230)
Total	147
Duke Energy Florida [Member]
Operating Leased Assets
Rental expense on operating leases	81	96	72
Operating Leases, Future Minimum Payments Due [Abstract]
2016	66
2017	48
2018	47
2019	46
2020	45
Thereafter	257
Total future minimum lease payments	509
Capital Leases, Future Minimum Payments Due [Abstract]
2016	26
2017	25
2018	25
2019	25
2020	25
Thereafter	95
Minimum annual payments	221
Less amount representing interest	(65)
Total	156
Duke Energy Ohio [Member]
Operating Leased Assets
Rental expense on operating leases	13	17	14
Operating Leases, Future Minimum Payments Due [Abstract]
2016	13
2017	9
2018	6
2019	4
2020	3
Thereafter	5
Total future minimum lease payments	40
Capital Leases, Future Minimum Payments Due [Abstract]
2016	7
2017	1
2018	5
2019	1
Thereafter	1
Minimum annual payments	15
Less amount representing interest	(2)
Total	13
Duke Energy Indiana [Member]
Operating Leased Assets
Rental expense on operating leases	20	$ 21	$ 22
Operating Leases, Future Minimum Payments Due [Abstract]
2016	20
2017	15
2018	12
2019	8
2020	5
Thereafter	8
Total future minimum lease payments	68
Capital Leases, Future Minimum Payments Due [Abstract]
2016	3
2017	1
2018	2
2019	1
2020	1
Thereafter	43
Minimum annual payments	51
Less amount representing interest	(38)
Total	$ 13