Joint Ownership of Generating and Transmission Facilities Joint Ownership of Generating and Transmission Facilities (Table) (Details) $ in Millions	Dec. 31, 2015 USD ($)
International Energy Brazil-Canoas I and II [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	47.20%
Property, plant, and equipment	$ 160
Accumulated depreciation	$ 57
Duke Energy Carolinas [Member] \| Duke Energy Carolinas Catawba Nuclear Station (Units 1 and 2) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	19.25%
Property, plant, and equipment	$ 926
Accumulated depreciation	567
Construction work in progress	$ 9
Duke Energy Florida [Member] \| Duke Energy Florida Intercession City Station (Unit P11) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	66.67%
Property, plant, and equipment	$ 24
Accumulated depreciation	15
Duke Energy Ohio [Member] \| Duke Energy Ohio Transmission [Member]
Jointly Owned Utility Plant Interests [Line Items]
Property, plant, and equipment	85
Accumulated depreciation	50
Construction work in progress	$ 1
Duke Energy Indiana [Member] \| Duke Energy Indiana Gibson Station (Unit 5) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	50.05%
Property, plant, and equipment	$ 329
Accumulated depreciation	151
Construction work in progress	$ 5
Duke Energy Indiana [Member] \| Vermillion Generation Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	62.50%
Property, plant, and equipment	$ 153
Accumulated depreciation	108
Construction work in progress	0
Duke Energy Indiana [Member] \| Duke Energy Indiana Transmission and local facilities [Member]
Jointly Owned Utility Plant Interests [Line Items]
Property, plant, and equipment	4,094
Accumulated depreciation	$ 1,688

The period end amount owned by the reporting utility of a jointly owned utility plant in service.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 980
-SubTopic 360
-Section S99
-Paragraph 1
-Subparagraph (SAB TOPIC 10.C)
-URI http://asc.fasb.org/extlink&oid=6500719&loc=d3e659983-123033

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher SEC
-Name Staff Accounting Bulletin (SAB)
-Number Topic 10
-Section C

+ Details

Name:	us-gaap_JointlyOwnedUtilityPlantGrossOwnershipAmountOfPlantInService
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
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_JointlyOwnedUtilityPlantInterestsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The period end amount of construction work in progress at a jointly owned electricity generation plant.

+ References

+ Details

Name:	us-gaap_JointlyOwnedUtilityPlantOwnershipAmountOfConstructionWorkInProgress
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The period end amount of accumulated depreciation in a jointly owned electricity generation plant.

+ References

+ Details

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

- Definition

The proportionate share of interest (percent) in a jointly owned utility plant.

+ References

+ Details

Name:	us-gaap_JointlyOwnedUtilityPlantProportionateOwnershipShare
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	us-gaap_JointlyOwnedUtilityPlantAxis=duk_InternationalEnergyBrazilCanoasIAndIiMemberMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

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

- Details

Name:	us-gaap_JointlyOwnedUtilityPlantAxis=duk_CatawbaNuclearStationUnits1And2Member
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:	us-gaap_JointlyOwnedUtilityPlantAxis=duk_IntercessionCityStationUnitP11Member
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:	us-gaap_JointlyOwnedUtilityPlantAxis=duk_TransmissionMember
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_JointlyOwnedUtilityPlantAxis=duk_GibsonStationUnit5Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_JointlyOwnedUtilityPlantAxis=duk_VermillionStationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_JointlyOwnedUtilityPlantAxis=duk_TransmissionAndLocalFacilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: