Debt and Credit Facilities (Summary of Debt Issuances) (Details) - USD ($)	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019
Debt Instrument [Line Items]
Debt issuances	$ 3,250,000,000
Repayments of long-term debt	1,951,000,000	$ 2,155,000,000
Duke Energy (Parent)
Debt Instrument [Line Items]
Debt issuances	500,000,000
Duke Energy (Parent) | Revolving Credit Facility
Debt Instrument [Line Items]
Repayments of long-term debt	500,000,000
Duke Energy Carolinas
Debt Instrument [Line Items]
Debt issuances	900,000,000
Repayments of long-term debt	454,000,000	3,000,000
Duke Energy Florida
Debt Instrument [Line Items]
Debt issuances	500,000,000
Repayments of long-term debt	537,000,000	136,000,000
Duke Energy Ohio
Debt Instrument [Line Items]
Debt issuances	400,000,000
Repayments of long-term debt		451,000,000
Duke Energy Indiana
Debt Instrument [Line Items]
Debt issuances	550,000,000
Repayments of long-term debt		60,000,000
Piedmont Natural Gas
Debt Instrument [Line Items]
Debt issuances	$ 400,000,000
Repayments of long-term debt		$ 350,000,000
Unsecured Debt | May 2020 2.450% Due 2030
Debt Instrument [Line Items]
Interest Rate	2.45%
Debt issuances	$ 500,000,000
Unsecured Debt | May 2020 3.350% Due 2050
Debt Instrument [Line Items]
Interest Rate	3.35%
Debt issuances	$ 400,000,000
Unsecured Debt | Duke Energy (Parent) | May 2020 2.450% Due 2030
Debt Instrument [Line Items]
Debt issuances	500,000,000
Unsecured Debt | Piedmont Natural Gas | May 2020 3.350% Due 2050
Debt Instrument [Line Items]
Debt issuances	$ 400,000,000
First Mortgage Bonds | January 2020 2.450% Due 2030
Debt Instrument [Line Items]
Interest Rate	2.45%
Debt issuances	$ 500,000,000
Repayments of long-term debt	$ 450,000,000
First Mortgage Bonds | January 2020 3.20% Due 2049
Debt Instrument [Line Items]
Interest Rate	3.20%
Debt issuances	$ 400,000,000
First Mortgage Bonds | March 2020 2.750% Due 2050
Debt Instrument [Line Items]
Interest Rate	2.75%
Debt issuances	$ 550,000,000
Repayments of long-term debt	$ 500,000,000
First Mortgage Bonds | May 2020 2.125% Due 2030
Debt Instrument [Line Items]
Interest Rate	2.125%
Debt issuances	$ 400,000,000
First Mortgage Bonds | June 2020 1.750% Due 2030
Debt Instrument [Line Items]
Interest Rate	1.75%
Debt issuances	$ 500,000,000
First Mortgage Bonds | Duke Energy Carolinas | January 2020 2.450% Due 2030
Debt Instrument [Line Items]
Debt issuances	500,000,000
First Mortgage Bonds | Duke Energy Carolinas | January 2020 3.20% Due 2049
Debt Instrument [Line Items]
Debt issuances	400,000,000
First Mortgage Bonds | Duke Energy Florida | June 2020 1.750% Due 2030
Debt Instrument [Line Items]
Debt issuances	500,000,000
First Mortgage Bonds | Duke Energy Ohio | May 2020 2.125% Due 2030
Debt Instrument [Line Items]
Debt issuances	400,000,000
First Mortgage Bonds | Duke Energy Indiana | March 2020 2.750% Due 2050
Debt Instrument [Line Items]
Debt issuances	$ 550,000,000