Debt and Credit Facilities (Summary of Debt Issuances) (Details) - USD ($) $ in Millions	Mar. 31, 2017	Dec. 31, 2016
Debt Instrument [Line Items]
Debt issuances	$ 1,587
Current maturities of long-term debt	1,977	$ 2,319
Duke Energy Carolinas [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	404	116
Duke Energy Progress [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	202	452
Duke Energy Florida [Member]
Debt Instrument [Line Items]
Debt issuances	900
Current maturities of long-term debt	319	326
Duke Energy Ohio [Member]
Debt Instrument [Line Items]
Debt issuances	100
Current maturities of long-term debt	1	1
Duke Energy Indiana [Member]
Debt Instrument [Line Items]
Current maturities of long-term debt	3	$ 3
Secured Debt [Member] \| February 2017 Debt Issuance, 4.120% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 587
Interest rate	4.12%
First Mortgage [Member] \| January 2017 Debt Issuance, 1.850% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 250
Interest rate	1.85%
First Mortgage [Member] \| January 2017 Debt Issuance, 3.200% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 650
Interest rate	3.20%
First Mortgage [Member] \| March 2017 Debt Issuance, 3.700% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 100
Interest rate	3.70%
First Mortgage [Member] \| Duke Energy Florida [Member] \| January 2017 Debt Issuance, 1.850% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 250
Interest rate	1.85%
First Mortgage [Member] \| Duke Energy Florida [Member] \| January 2017 Debt Issuance, 3.200% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 650
Interest rate	3.20%
First Mortgage [Member] \| Duke Energy Florida [Member] \| First Mortgage Bonds Maturing September 2017, 5.800% Coupon [Member]
Debt Instrument [Line Items]
Interest rate	5.80%
Current maturities of long-term debt	$ 250
First Mortgage [Member] \| Duke Energy Ohio [Member] \| March 2017 Debt Issuance, 3.700% Coupon [Member]
Debt Instrument [Line Items]
Debt issuances	$ 100
Interest rate	3.70%

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

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

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

- Definition

Contractual interest rate for funds borrowed, under the debt 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(a)(1))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

Name:	us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
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

Name:	us-gaap_DebtInstrumentLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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.

+ 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 210.5-02.19,20)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Details

Name:	dei_LegalEntityAxis=duk_DukeEnergyCarolinasMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=duk_DukeEnergyProgressMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=duk_DukeEnergyFloridaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=duk_DukeEnergyOhioMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=duk_DukeEnergyIndianaMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_SecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=duk_February2017DebtIssuance4.120CouponMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_FirstMortgageMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=duk_January2017DebtIssuance1.850CouponMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=duk_January2017DebtIssuance3.200CouponMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=duk_March2017DebtIssuance3.700CouponMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=duk_September2017DebtMaturityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: