Debt and Credit Facilities (Annual Maturities) (Details) - USD ($)	Dec. 31, 2018	Dec. 31, 2017
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	$ 3,406,000,000	$ 3,244,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
2019	3,408,000,000
2020	3,765,000,000
2021	4,803,000,000
2022	2,745,000,000
2023	3,375,000,000
Thereafter	35,288,000,000
Total long-term debt, including current maturities	53,384,000,000
Purchase accounting adjustments	1,600,000,000	1,700,000,000
Other Debt Obligations [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	606,000,000
Purchase Accounting Adjustments [Member]
Long-term Debt, Fiscal Year Maturity [Abstract]
Purchase accounting adjustments	$ (1,578,000,000)
Parent Company [Member] \| Debt Maturing September 2019, 5.050% Coupon [Member] \| Unsecured Debt [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	5.05%
Current maturities of long-term debt	$ 500,000,000
Duke Energy Carolinas [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	6,000,000	1,205,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
2019	6,000,000
2020	907,000,000
2021	503,000,000
2022	353,000,000
2023	1,303,000,000
Thereafter	7,940,000,000
Total long-term debt, including current maturities	11,012,000,000
Progress Energy [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	1,672,000,000	771,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
2019	1,674,000,000
2020	926,000,000
2021	2,004,000,000
2022	1,032,000,000
2023	535,000,000
Thereafter	12,880,000,000
Total long-term debt, including current maturities	$ 19,051,000,000
Progress Energy [Member] \| Debt Maturing March 2019, 7.050% Coupon [Member] \| Unsecured Debt [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	7.05%
Current maturities of long-term debt	$ 450,000,000
Duke Energy Progress [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	603,000,000	3,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
2019	603,000,000
2020	354,000,000
2021	904,000,000
2022	505,000,000
2023	456,000,000
Thereafter	5,437,000,000
Total long-term debt, including current maturities	$ 8,259,000,000
Duke Energy Progress [Member] \| Bonds Maturing January 2019, 5.300% Coupon [Member] \| First Mortgage Bonds [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	5.30%
Current maturities of long-term debt	$ 600,000,000
Duke Energy Florida [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	270,000,000	768,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
2019	270,000,000
2020	572,000,000
2021	600,000,000
2022	77,000,000
2023	79,000,000
Thereafter	5,793,000,000
Total long-term debt, including current maturities	7,391,000,000
Duke Energy Ohio [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	551,000,000	3,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
2019	552,000,000
2020	0
2021	50,000,000
2022	0
2023	350,000,000
Thereafter	1,251,000,000
Total long-term debt, including current maturities	$ 2,203,000,000
Duke Energy Ohio [Member] \| Bonds Maturing April 2019, 5.450% Coupon [Member] [Member] \| First Mortgage Bonds [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	5.45%
Current maturities of long-term debt	$ 450,000,000
Duke Energy Indiana [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	63,000,000	3,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
2019	63,000,000
2020	503,000,000
2021	70,000,000
2022	94,000,000
2023	153,000,000
Thereafter	2,925,000,000
Total long-term debt, including current maturities	3,808,000,000
Piedmont Natural Gas [Member]
Current Maturities Of Long Term Debt [Abstract]
Current maturities of long-term debt	350,000,000	$ 250,000,000
Long-term Debt, Fiscal Year Maturity [Abstract]
2019	350,000,000
2020	0
2021	160,000,000
2022	0
2023	45,000,000
Thereafter	1,595,000,000
Total long-term debt, including current maturities	$ 2,150,000,000
Piedmont Natural Gas [Member] \| Debt Maturing September 2019, 3.155% Coupon [Member] \| Unsecured Debt [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	3.155%
Current maturities of long-term debt	$ 350,000,000
Piedmont Natural Gas [Member] \| Debt Maturing December 2019, 4.875% Coupon [Member] \| Unsecured Debt [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	4.875%
Current maturities of long-term debt	$ 350,000,000
Duke Energy Kentucky [Member] \| Debt Maturing October 2019, 4.65% Coupon [Member] \| Unsecured Debt [Member]
Current Maturities Of Long Term Debt [Abstract]
Interest rate	4.65%
Current maturities of long-term debt	$ 100,000,000

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Including current and noncurrent portions, aggregate carrying amount of long-term borrowings as of the balance sheet date, excluding purchase accounting adjustments.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount of unamortized debt discount (premium) and debt issuance costs.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the next fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the second fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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