The amount of borrowing capacity extended with consenting lenders, as part of amendment to credit facility.

No definition available.

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- Definition

Minimum Master Credit Facility Balance Required to be maintained to meet obligations outlined in Plea Agreements

+ References

No definition available.

+ Details

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- Definition

Other Debt Matters [Abstract]

+ References

No definition available.

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- Definition

Other Loans [Abstract]

+ References

No definition available.

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- Definition

Restrictive Debt Covenants [Abstract]

+ References

No definition available.

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- Definition

The amount of subsidiary debt guaranteed by its parent.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Maximum amount of unsecured variable denomination floating rate demand notes available for sale.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
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Period Type:	instant

- Definition

Maximum amount of unsecured variable denomination floating rate demand notes that can be outstanding at any point in time.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

Principal amount of unsecured variable denomination floating rate demand notes that are outstanding at the balance sheet date.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

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- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Date the credit facility terminates, in CCYY-MM-DD format.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:dateItemType
Balance Type:	na
Period Type:	duration

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of long-term loans payable classified as other.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
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-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Indebtedness divided by net capital.

+ References

No definition available.

+ Details

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Period Type:	instant

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- Details

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- Details

Name:	us-gaap_CreditFacilityAxis=duk_June2017ThreeYearRevolvingCreditFacilityMember
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- Details

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Debt and Credit Facilities (Narrative) (Details)	1 Months Ended	12 Months Ended
Debt and Credit Facilities (Narrative) (Details)	Jan. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Feb. 28, 2017 USD ($)	Dec. 31, 2016 USD ($)	Aug. 01, 2016 USD ($)
Debt Instrument [Line Items]
Debt issuances		$ 6,070,000,000				$ 9,127,000,000
Other Debt Matters [Abstract]
Demand notes, maximum amount available for sale		3,000,000,000
Demand notes, maximum amount outstanding		1,500,000,000
Principal amount of demand notes		986,000,000				1,090,000,000
Subsidiary debt guaranteed by parent		650,000,000				762,000,000
Other Loans [Abstract]
Other loans outstanding against cash surrender value of life insurance policies		$ 701,000,000				661,000,000
Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower		0.65
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size		$ 8,000,000,000		$ 8,000,000,000	$ 7,500,000,000.0
June 2017 Three Year Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size			$ 1,000,000,000.0
Debt Instrument, Term		3 years
Long-term Line of Credit		$ 500,000,000
Term Loan Proceeds		500,000,000
Subsequent Event [Member]
Debt Instrument [Line Items]
Amount Of Borrowing Capacity Extended With Consenting Lenders	$ 7,650,000,000
Line of credit facility, expiration date	Mar. 16, 2023
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Debt issuances		$ 550,000,000				1,600,000,000
Duke Energy Carolinas [Member] \| Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower		0.65
Duke Energy Carolinas [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size		$ 1,350,000,000
Progress Energy [Member] \| Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower		0.65
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Debt issuances		$ 800,000,000				450,000,000
Other Loans [Abstract]
Other loans outstanding against cash surrender value of life insurance policies		$ 38,000,000				39,000,000
Duke Energy Progress [Member] \| Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower		0.65
Duke Energy Progress [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size		$ 1,250,000,000
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Debt issuances		$ 1,300,000,000				1,894,000,000
Duke Energy Florida [Member] \| Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower		0.65
Duke Energy Florida [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size		$ 800,000,000
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Debt issuances		$ 100,000,000				250,000,000
Duke Energy Ohio [Member] \| Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower		0.65
Duke Energy Ohio [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size		$ 450,000,000
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Debt issuances						$ 500,000,000
Duke Energy Indiana [Member] \| Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower		0.65
Duke Energy Indiana [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size		$ 600,000,000
Piedmont Natural Gas [Member] \| Maximum [Member]
Restrictive Debt Covenants [Abstract]
Debt to total capitalization percentage, for each borrower		0.7
Piedmont Natural Gas [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Facility Size		$ 700,000,000			$ 850,000,000
Piedmont Natural Gas [Member] \| June 2017 Piedmont Term Loan Facility [Member]
Debt Instrument [Line Items]
Facility Size			$ 250,000,000
Debt Instrument, Term		18 months
Long-term Line of Credit		$ 250,000,000
Term Loan Proceeds		250,000,000
Piedmont Natural Gas [Member]
Debt Instrument [Line Items]
Facility Size							$ 4,900,000,000
USDOJ [Member] \| North Carolina Ash Basins [Member] \| Duke Energy Carolinas [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Minimum Master Credit Facility Balance required		250,000,000
USDOJ [Member] \| North Carolina Ash Basins [Member] \| Duke Energy Progress [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Minimum Master Credit Facility Balance required		$ 250,000,000