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Debt and Credit Facilities (Summary of Debt Issuances) (Details) - USD ($)	6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Debt Instrument [Line Items]
Debt issuances	$ 4,350,000,000
Repayments of long-term debt	2,002,000,000	$ 1,951,000,000
Duke Energy (Parent)
Debt Instrument [Line Items]
Debt issuances	3,000,000,000
Repayments of long-term debt	1,750,000,000
Duke Energy Carolinas
Debt Instrument [Line Items]
Debt issuances	1,000,000,000
Repayments of long-term debt	614,000,000	$ 454,000,000
Piedmont
Debt Instrument [Line Items]
Debt issuances	350,000,000
Repayments of long-term debt	160,000,000
Unsecured Debt
Debt Instrument [Line Items]
Repayments of long-term debt	$ 160,000,000
Unsecured Debt \| March 2021 Notes Due March 2031
Debt Instrument [Line Items]
Interest Rate	2.50%
Debt issuances	$ 350,000,000
Unsecured Debt \| June 2021 Notes Due June 2023
Debt Instrument [Line Items]
Interest Rate	2.50%
Debt issuances	$ 500,000,000
Unsecured Debt \| June 2021 Notes Due June 2031
Debt Instrument [Line Items]
Interest Rate	2.55%
Debt issuances	$ 1,000,000,000
Unsecured Debt \| June 2021 Notes Due June 2041
Debt Instrument [Line Items]
Interest Rate	3.30%
Debt issuances	$ 750,000,000
Unsecured Debt \| June 2021 Notes Due June 2051
Debt Instrument [Line Items]
Interest Rate	3.50%
Debt issuances	$ 750,000,000
Unsecured Debt \| Duke Energy (Parent) \| June 2021 Notes Due June 2023
Debt Instrument [Line Items]
Debt issuances	500,000,000
Unsecured Debt \| Duke Energy (Parent) \| June 2021 Notes Due June 2031
Debt Instrument [Line Items]
Debt issuances	1,000,000,000
Unsecured Debt \| Duke Energy (Parent) \| June 2021 Notes Due June 2041
Debt Instrument [Line Items]
Debt issuances	750,000,000
Unsecured Debt \| Duke Energy (Parent) \| June 2021 Notes Due June 2051
Debt Instrument [Line Items]
Debt issuances	750,000,000
Unsecured Debt \| Piedmont \| March 2021 Notes Due March 2031
Debt Instrument [Line Items]
Debt issuances	$ 350,000,000
First Mortgage Bonds \| April 2021 Notes Due April 2031
Debt Instrument [Line Items]
Interest Rate	2.55%
Debt issuances	$ 550,000,000
First Mortgage Bonds \| April 2021 Notes Due April 2051
Debt Instrument [Line Items]
Interest Rate	3.45%
Debt issuances	$ 450,000,000
First Mortgage Bonds \| Duke Energy Carolinas \| April 2021 Notes Due April 2031
Debt Instrument [Line Items]
Debt issuances	550,000,000
First Mortgage Bonds \| Duke Energy Carolinas \| April 2021 Notes Due April 2051
Debt Instrument [Line Items]
Debt issuances	450,000,000
First Mortgage Bonds \| Duke Energy Carolinas \| Bonds maturing June 2021, 3.900% interest rate
Debt Instrument [Line Items]
Repayments of long-term debt	$ 500,000,000