Debt and Credit Facilities (Summary of Debt Issuances) (Details) - USD ($)	3 Months Ended
Mar. 31, 2021	Mar. 31, 2020
Debt Instrument [Line Items]
Debt issuances	$ 350,000,000
Repayments of long-term debt	76,000,000	$ 292,000,000
Duke Energy (Parent)
Debt Instrument [Line Items]
Debt issuances	0
Duke Energy Carolinas
Debt Instrument [Line Items]
Debt issuances	0
Repayments of long-term debt	33,000,000	2,000,000
Duke Energy Progress
Debt Instrument [Line Items]
Debt issuances	0
Repayments of long-term debt	2,000,000	1,000,000
Duke Energy Florida
Debt Instrument [Line Items]
Debt issuances	0
Repayments of long-term debt	33,000,000	$ 282,000,000
Duke Energy Ohio
Debt Instrument [Line Items]
Debt issuances	0
Duke Energy Indiana
Debt Instrument [Line Items]
Debt issuances	0
Piedmont
Debt Instrument [Line Items]
Debt issuances	350,000,000
Unsecured Debt
Debt Instrument [Line Items]
Repayments of long-term debt	$ 160,000,000
Unsecured Debt \| March 2021
Debt Instrument [Line Items]
Interest Rate	2.50%
Debt issuances	$ 350,000,000
Unsecured Debt \| Duke Energy (Parent) \| March 2021
Debt Instrument [Line Items]
Debt issuances	0
Unsecured Debt \| Piedmont \| March 2021
Debt Instrument [Line Items]
Debt issuances	$ 350,000,000

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

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
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Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
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Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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