Commitments and Contingencies (Future Minimum Payments for Operating and Capital Leases) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Operating Leased Assets
Rental expense on operating leases	$ 355	$ 321	$ 232
Operating Leases, Future Minimum Payments Due [Abstract]
2015	205
2016	198
2017	172
2018	157
2019	148
Thereafter	938
Total future minimum lease payments	1,818
Capital Leases, Future Minimum Payments Due [Abstract]
2015	178
2016	188
2017	190
2018	198
2019	208
Thereafter	1,771
Minimum annual payments	2,733
Less amount representing interest	(1,305)
Total	1,428
Duke Energy Carolinas [Member]
Operating Leased Assets
Rental expense on operating leases	41	39	38
Operating Leases, Future Minimum Payments Due [Abstract]
2015	33
2016	29
2017	26
2018	20
2019	17
Thereafter	64
Total future minimum lease payments	189
Capital Leases, Future Minimum Payments Due [Abstract]
2015	6
2016	6
2017	7
2018	7
2019	8
Thereafter	60
Minimum annual payments	94
Less amount representing interest	(67)
Total	27
Progress Energy [Member]
Operating Leased Assets
Rental expense on operating leases	257	225	232
Operating Leases, Future Minimum Payments Due [Abstract]
2015	129
2016	130
2017	111
2018	109
2019	103
Thereafter	709
Total future minimum lease payments	1,291
Capital Leases, Future Minimum Payments Due [Abstract]
2015	46
2016	47
2017	47
2018	48
2019	51
Thereafter	678
Minimum annual payments	917
Less amount representing interest	(603)
Total	314
Duke Energy Progress [Member]
Operating Leased Assets
Rental expense on operating leases	161	153	164
Operating Leases, Future Minimum Payments Due [Abstract]
2015	65
2016	66
2017	65
2018	64
2019	58
Thereafter	421
Total future minimum lease payments	739
Capital Leases, Future Minimum Payments Due [Abstract]
2015	21
2016	21
2017	21
2018	22
2019	25
Thereafter	398
Minimum annual payments	508
Less amount representing interest	(361)
Total	147
Duke Energy Florida [Member]
Operating Leased Assets
Rental expense on operating leases	96	72	68
Operating Leases, Future Minimum Payments Due [Abstract]
2015	64
2016	64
2017	46
2018	45
2019	45
Thereafter	288
Total future minimum lease payments	552
Capital Leases, Future Minimum Payments Due [Abstract]
2015	26
2016	26
2017	26
2018	26
2019	26
Thereafter	280
Minimum annual payments	410
Less amount representing interest	(242)
Total	168
Duke Energy Ohio [Member]
Operating Leased Assets
Rental expense on operating leases	17	14	14
Operating Leases, Future Minimum Payments Due [Abstract]
2015	12
2016	11
2017	9
2018	7
2019	6
Thereafter	18
Total future minimum lease payments	63
Capital Leases, Future Minimum Payments Due [Abstract]
2015	7
2016	7
2017	3
2018	4
2019	2
Minimum annual payments	23
Less amount representing interest	(3)
Total	20
Duke Energy Indiana [Member]
Operating Leased Assets
Rental expense on operating leases	21	22	20
Operating Leases, Future Minimum Payments Due [Abstract]
2015	17
2016	15
2017	13
2018	10
2019	9
Thereafter	9
Total future minimum lease payments	73
Capital Leases, Future Minimum Payments Due [Abstract]
2015	4
2016	4
2017	2
2018	2
2019	2
Thereafter	42
Minimum annual payments	56
Less amount representing interest	(39)
Total	$ 17