v3.3.0.814

Employee Benefit Plans (Narrative) (Details) - USD ($) $ in Millions | 3 Months Ended | 9 Months Ended
--- | --- | ---
Sep. 30, 2015 | Sep. 30, 2015
Defined Benefit Plan Disclosure [Line Items] |  |
Defined Benefit Plan, Maximum years of participation |  | 35 years
Matching contribution percentage |  | 100.00%
Eligible pay percentage |  | 6.00%
Additional savings plan account contribution percentage for employees not participating in defined pension plans |  | 4.00%
Qualified Pension Plans [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Contributions by employer | $ 11 | $ 143
Duke Energy Carolinas [Member] | Qualified Pension Plans [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Contributions by employer |  | 42
Progress Energy [Member] | Qualified Pension Plans [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Contributions by employer |  | 42
Duke Energy Progress [Member] | Qualified Pension Plans [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Contributions by employer |  | 21
Duke Energy Florida [Member] | Qualified Pension Plans [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Contributions by employer |  | 21
Duke Energy Ohio [Member] | Qualified Pension Plans [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Contributions by employer | $ 3 | 4
Duke Energy Indiana [Member] | Qualified Pension Plans [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Contributions by employer |  | $ 9

X
- Definition Defined Benefit Plan, Maximum years of participation + References No definition available. + Details
Name: | duk_DefinedBenefitPlanMaximumyearsofparticipation
Namespace Prefix: | duk_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of eligible pay per period contributed to an employee's 401(k) account in lieu of participation in Duke Energy's defined pension plans. + References No definition available. + Details
Name: | duk_DefinedContributionPlanAdditionalContributionPercentageForEmployeesNotParticipatingInDefinedPensionPlans
Namespace Prefix: | duk_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The increase in the fair value of plan assets from contributions made by the employer. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 715 -SubTopic 20 -Section 50 -Paragraph 1 -Subparagraph (b)(3) -URI http://asc.fasb.org/extlink&oid=58740216&loc=d3e1928-114920 + Details
Name: | us-gaap_DefinedBenefitPlanContributionsByEmployer
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

X
- 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_DefinedBenefitPlanDisclosureLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage of employees' gross pay for which the employer contributes a matching contribution to a defined contribution plan. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercent
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Percentage employer matches of the employee's percentage contribution matched. + References No definition available. + Details
Name: | us-gaap_DefinedContributionPlanEmployerMatchingContributionPercentOfMatch
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis=us-gaap_PensionPlansDefinedBenefitMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=duk_DukeEnergyCarolinasMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=duk_ProgressEnergyMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=duk_DukeEnergyProgressMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=duk_DukeEnergyFloridaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=duk_DukeEnergyOhioMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | dei_LegalEntityAxis=duk_DukeEnergyIndianaMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |