v2.4.0.6

Employee Benefit Plans (Narrative) (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended
--- | ---
Mar. 31, 2013 | Mar. 31, 2012
Defined Benefit Plan Disclosure [Line Items] |  |
Defined contribution plan contribution by employer | $ 41 | $ 28
Duke Energy Carolinas [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Defined contribution plan contribution by employer | 14 | 11
Progress Energy [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Defined contribution plan contribution by employer | 12 | 12
Duke Energy Progress [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Defined contribution plan contribution by employer | 6 | 6
Duke Energy Florida [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Defined contribution plan contribution by employer | 4 | 4
Duke Energy Ohio [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Defined contribution plan contribution by employer | 1 | 1
Duke Energy Indiana [Member] |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Defined contribution plan contribution by employer | $ 2 | $ 2

X
- Definition Defined contribution plan contribution by employer + References No definition available. + Details
Name: | duk_DefinedContributionPlanContributionByEmployer
Namespace Prefix: | duk_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | duration

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