Goodwill and Intangible Assets (Schedule of Intangible Assets) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	$ 300	$ 276
Accumulated amortization	(54)	(46)
Total intangible assets, net	246	230
Asset Impairment Charges	402	282	$ 18
Wind Project [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Asset Impairment Charges	69
Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	18	19
Renewable Energy Certificates [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	168	148
Gas Coal And Power Contracts [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	24	24
Accumulated amortization	(20)	(19)
Renewable Operating and Development Projects [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	84	79
Accumulated amortization	(29)	(22)
Asset Impairment Charges		69
Renewable Operating and Development Projects [Member] | Property, Plant and Equipment [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Asset Impairment Charges		58
Renewable Operating and Development Projects [Member] | Finite-Lived Intangible Assets [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Asset Impairment Charges		11
Renewable Operating and Development Projects [Member] | Wind Project [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount		18
Accumulated amortization		(7)
Other Intangible Assets [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	6	6
Accumulated amortization	(5)	(5)
Duke Energy Carolinas [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	46	39
Total intangible assets, net	46	39
Asset Impairment Charges	192		1
Duke Energy Carolinas [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	0	1
Duke Energy Carolinas [Member] | Renewable Energy Certificates [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	46	38
Progress Energy [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	125	112
Total intangible assets, net	125	112
Asset Impairment Charges	87	156	7
Progress Energy [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	5	5
Progress Energy [Member] | Renewable Energy Certificates [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	120	107
Duke Energy Progress [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	122	109
Total intangible assets, net	122	109
Asset Impairment Charges	33	19	1
Duke Energy Progress [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	2	2
Duke Energy Progress [Member] | Renewable Energy Certificates [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	120	107
Duke Energy Florida [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	3	3
Total intangible assets, net	3	3
Asset Impairment Charges	54	138	6
Duke Energy Florida [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	3	3
Duke Energy Ohio [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	2	3
Total intangible assets, net	2	3
Asset Impairment Charges		1
Duke Energy Ohio [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	0	0
Duke Energy Ohio [Member] | Renewable Energy Certificates [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	2	3
Duke Energy Ohio [Member] | Other Intangible Assets [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	0	0
Accumulated amortization	0	0
Duke Energy Indiana [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	36	37
Accumulated amortization	(20)	(19)
Total intangible assets, net	16	18
Asset Impairment Charges	30	18	$ 8
Duke Energy Indiana [Member] | Emission Allowances [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	12	13
Duke Energy Indiana [Member] | Gas Coal And Power Contracts [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	24	24
Accumulated amortization	(20)	(19)
Piedmont Natural Gas [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	3	3
Accumulated amortization	(3)	(3)
Asset Impairment Charges		7
Piedmont Natural Gas [Member] | Other Intangible Assets [Member]
Finite-Lived Intangible Assets, Net [Abstract]
Gross carrying amount	3	3
Accumulated amortization	$ (3)	$ (3)