Face (par) amount of debt instrument at time of issuance.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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Contractual interest rate for funds borrowed, under the debt agreement.

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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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The cash outflow for debt initially having maturity due after one year or beyond the normal operating cycle, if longer.

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Debt and Credit Facilities (Summary of Debt Issuances) (Details) - USD ($)	1 Months Ended	6 Months Ended
	Apr. 30, 2018	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Debt Instrument [Line Items]
Debt issuances		$ 2,750,000,000
Current maturities of long-term debt		2,852,000,000		$ 3,244,000,000
Repayments of Long-term Debt		2,190,000,000	$ 1,009,000,000
Parent Company [Member]
Debt Instrument [Line Items]
Debt issuances		750,000,000
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Debt issuances		1,000,000,000
Current maturities of long-term debt		505,000,000		1,205,000,000
Repayments of Long-term Debt		702,000,000	114,000,000
Duke Energy Carolinas [Member] \| First Mortgage Bonds Maturing April 2018, 5.100% Coupon
Debt Instrument [Line Items]
Repayments of Long-term Debt	$ 300,000,000
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Debt issuances		1,000,000,000
Current maturities of long-term debt		269,000,000		$ 768,000,000
Repayments of Long-term Debt		635,000,000	$ 57,000,000
Unsecured Debt [Member] \| March 2018 Debt Issuance 3.950% Coupon Due 2025 [Member]
Debt Instrument [Line Items]
Debt issuances		$ 250,000,000
Interest rate		3.95%
Unsecured Debt [Member] \| May 2018 Debt Issuance 2.830% Coupon Due 2021 [Member] [Member]
Debt Instrument [Line Items]
Debt issuances		$ 500,000,000
Interest rate		2.83%
Unsecured Debt [Member] \| Parent Company [Member] \| March 2018 Debt Issuance 3.950% Coupon Due 2025 [Member]
Debt Instrument [Line Items]
Debt issuances		$ 250,000,000
Unsecured Debt [Member] \| Parent Company [Member] \| May 2018 Debt Issuance 2.830% Coupon Due 2021 [Member] [Member]
Debt Instrument [Line Items]
Debt issuances		500,000,000
First Mortgage [Member] \| March 2018 Debt Issuance 3.050% Coupon Due 2023 [Member]
Debt Instrument [Line Items]
Debt issuances		$ 500,000,000
Interest rate		3.05%
First Mortgage [Member] \| March 2018 Debt Issuance 3.950% Coupon Due 2048 [Member]
Debt Instrument [Line Items]
Debt issuances		$ 500,000,000
Interest rate		3.95%
First Mortgage [Member] \| June 2018 Debt issuance 3.80% coupon Due 2028 [Member]
Debt Instrument [Line Items]
Debt issuances		$ 600,000,000
Interest rate		3.80%
First Mortgage [Member] \| June 2018 Debt Issuance 4.20 Coupon Due 2048 [Member]
Debt Instrument [Line Items]
Debt issuances		$ 400,000,000
Interest rate		4.20%
First Mortgage [Member] \| Duke Energy Carolinas [Member] \| March 2018 Debt Issuance 3.050% Coupon Due 2023 [Member]
Debt Instrument [Line Items]
Debt issuances		$ 500,000,000
First Mortgage [Member] \| Duke Energy Carolinas [Member] \| March 2018 Debt Issuance 3.950% Coupon Due 2048 [Member]
Debt Instrument [Line Items]
Debt issuances		500,000,000
First Mortgage [Member] \| Duke Energy Florida [Member] \| June 2018 Debt issuance 3.80% coupon Due 2028 [Member]
Debt Instrument [Line Items]
Debt issuances		600,000,000
First Mortgage [Member] \| Duke Energy Florida [Member] \| June 2018 Debt Issuance 4.20 Coupon Due 2048 [Member]
Debt Instrument [Line Items]
Debt issuances		$ 400,000,000