Debt and Credit Facilities (Summary of Current Maturities of Long-term Debt) (Details) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 3,096	$ 3,406
Other debt obligations [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	566
Parent Company [Member] | Unsecured Debt [Member] | Debt Maturing September 2019, 5.050% Coupon [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 500
Parent Company [Member] | Unsecured Debt [Member] | Debt Maturing June 2020, 2.100% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	2.10%
Current maturities of long-term debt	$ 330
Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt		350
Duke Energy Kentucky [Member] | Secured Debt [Member] | Debt Maturing October 2019, 4.650% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	4.65%
Current maturities of long-term debt	$ 100
Progress Energy [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 1,276	1,672
Progress Energy [Member] | Secured Debt [Member] | Debt Maturing December 2019, 4.875% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	4.875%
Current maturities of long-term debt	$ 350
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 621	270
Duke Energy Florida [Member] | First Mortgage Bonds [Member] | Bonds Maturing January 2020, 1.850% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	1.85%
Current maturities of long-term debt	$ 250
Duke Energy Florida [Member] | First Mortgage Bonds [Member] | Bonds Maturing April 2020, 4.550% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	4.55%
Current maturities of long-term debt	$ 250
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 457	6
Duke Energy Carolinas [Member] | First Mortgage Bonds [Member] | Bonds Maturing June 2020, 4.300% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	4.30%
Current maturities of long-term debt	$ 450
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 651	63
Duke Energy Indiana [Member] | First Mortgage Bonds [Member] | Bonds Maturing July 2020, 3.750% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	3.75%
Current maturities of long-term debt	$ 500
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	$ 306	$ 603
Duke Energy Progress [Member] | First Mortgage Bonds [Member] | Bonds Maturing September 2020, 2.282% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	2.282%
Current maturities of long-term debt	$ 300