Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt) (Details) - USD ($) $ in Millions	Sep. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 4,669	$ 3,141
Other debt obligations
Debt Instrument [Line Items]
Current maturities of long-term debt	609
Progress Energy
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 1,726	1,577
Progress Energy | Unsecured Debt | Debt maturing January 2021, 4.400% interest rate
Debt Instrument [Line Items]
Interest Rate	4.40%
Current maturities of long-term debt	$ 500
Duke Energy (Parent) | Unsecured Debt | Debt maturing May 2021, floating interest rate
Debt Instrument [Line Items]
Interest Rate	0.765%
Current maturities of long-term debt	$ 500
Duke Energy (Parent) | Unsecured Debt | Debt maturing September 2021, 3.550% interest rate
Debt Instrument [Line Items]
Interest Rate	3.55%
Current maturities of long-term debt	$ 500
Duke Energy (Parent) | Unsecured Debt | Debt maturing September 2021, 1.800% interest rate
Debt Instrument [Line Items]
Interest Rate	1.80%
Current maturities of long-term debt	$ 750
Piedmont Natural Gas
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 160
Piedmont Natural Gas | Unsecured Debt | Debt maturing June 2021, 4.240% interest rate
Debt Instrument [Line Items]
Interest Rate	4.24%
Current maturities of long-term debt	$ 160
Duke Energy Florida
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 623	571
Duke Energy Florida | Secured Debt | Debt maturing April 2021, floating interest rate
Debt Instrument [Line Items]
Interest Rate	1.035%
Current maturities of long-term debt	$ 250
Duke Energy Florida | First Mortgage Bonds | Bonds maturing August 2021, 3.100% interest rate
Debt Instrument [Line Items]
Interest Rate	3.10%
Current maturities of long-term debt	$ 300
Duke Energy Carolinas
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 751	458
Duke Energy Carolinas | First Mortgage Bonds | Bonds maturing June 2021, 3.900% interest rate
Debt Instrument [Line Items]
Interest Rate	3.90%
Current maturities of long-term debt	$ 500
Duke Energy Progress
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 603	$ 1,006
Duke Energy Progress | First Mortgage Bonds | Debt maturing September 2021, 3.000% interest rate
Debt Instrument [Line Items]
Interest Rate	3.00%
Current maturities of long-term debt	$ 500
Duke Energy Progress | First Mortgage Bonds | Debt maturing September 2021, 8.625% interest rate
Debt Instrument [Line Items]
Interest Rate	8.625%
Current maturities of long-term debt	$ 100