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Regulatory Matters (Duke Energy Carolinas Narrative) (Details) $ in Millions									1 Months Ended		12 Months Ended
	Sep. 30, 2019 USD ($)	May 21, 2019 USD ($)	Nov. 08, 2018 USD ($)	Aug. 09, 2018 plant	Jul. 05, 2018 plant	Jun. 22, 2018 USD ($)	Feb. 15, 2018 USD ($)	Aug. 25, 2017 USD ($)	May 31, 2018 USD ($) plant MW	Feb. 28, 2018 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Aug. 16, 2019 USD ($)
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other											$ 6,066	$ 6,463	$ 5,944
Regulatory assets											15,018	15,622
AROs – coal ash
Public Utilities, General Disclosures [Line Items]
Regulatory assets											4,084	4,255
Duke Energy Carolinas
Public Utilities, General Disclosures [Line Items]
Operation, maintenance and other											1,868	2,130	$ 2,021
Regulatory assets											3,910	3,977
Duke Energy Carolinas | AROs – coal ash
Public Utilities, General Disclosures [Line Items]
Regulatory assets											$ 1,696	$ 1,725
Duke Energy Carolinas | NCUC | 2017 North Carolina Rate Case
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease)								$ 647
Requested rate increase (decrease), percent								13.60%
Requested return on equity, percentage										9.90%
Requested capital structure, percentage										52.00%
Requested debt structure, percentage										48.00%
Operation, maintenance and other										$ 4
Impairment charges and Operation						$ 150
Management penalty assessed						70
Reduction of annual recovery of deferred coal ash costs						$ 14
Duke Energy Carolinas | NCUC | 2019 North Carolina Rate Case
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease)	$ 291
Requested rate increase (decrease), percent	6.00%
Requested gross rate case revenue increase	$ 445
Requested EDIT rider decrease	$ 154
Duke Energy Carolinas | NCUC | 2018 Sale of Hydro Plants
Public Utilities, General Disclosures [Line Items]
Regulatory assets														$ 32
Number of Hydroelectric Plants | plant									5
Plant capacity | MW									18.7
Total estimated loss on the sale									$ 40
Duke Energy Carolinas | PSCSC | 2018 South Carolina Rate Case
Public Utilities, General Disclosures [Line Items]
Requested rate increase (decrease)			$ 168
Requested rate increase (decrease), percent			10.00%
Tax benefit from change in enacted tax rates		$ (66)	$ 66
Measurement period adjustments		$ 45	$ 46
Approved return on equity, percentage		9.50%
Approved capital structure, percentage		53.00%
Approved debt structure, percentage		47.00%
Duke Energy Carolinas | PSCSC | 2018 South Carolina Rate Case | AROs – coal ash
Public Utilities, General Disclosures [Line Items]
Recovery period			5 years
Regulatory assets		$ 96	$ 242
Denied recovery costs		$ 115
Duke Energy Carolinas | PSCSC | 2018 South Carolina Rate Case | Deferred project costs
Public Utilities, General Disclosures [Line Items]
Recovery period		12 years
Regulatory assets		$ 125
Duke Energy Carolinas | PSCSC | 2018 South Carolina Rate Case | State | North Carolina DOR
Public Utilities, General Disclosures [Line Items]
Tax benefit from reduction in state taxes			$ 17
Approved decrease through EDIT Rider		$ 17
Duke Energy Carolinas | FERC | FERC Formula Rate Matter
Public Utilities, General Disclosures [Line Items]
Customer refunds							$ 25
Duke Energy Carolinas | FERC | 2018 Sale of Hydro Plants
Public Utilities, General Disclosures [Line Items]
Number of Hydroelectric Plants | plant									4
Northbrook | Duke Energy Carolinas | NCUC | 2018 Sale of Hydro Plants
Public Utilities, General Disclosures [Line Items]
Number of Hydroelectric Plants | plant					5
Northbrook | Duke Energy Carolinas | NCUC | 2018 Sale of Hydro Plants, CPCNs
Public Utilities, General Disclosures [Line Items]
Number of Hydroelectric Plants | plant					4
Northbrook | Duke Energy Carolinas | FERC | 2018 Sale of Hydro Plants
Public Utilities, General Disclosures [Line Items]
Number of Hydroelectric Plants | plant				4

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