Variable Interest Entities (Receivables Sold)(Details) (Cinergy Receivables [Member], USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Duke Energy Ohio [Member]
Variable Interest Entity [Line Items]
Receivables sold	$ 235	$ 282
Less: retained interests	75	97
Net receivables sold	160	185
Duke Energy Indiana [Member]
Variable Interest Entity [Line Items]
Receivables sold	332	289
Less: retained interests	114	116
Net receivables sold	$ 218	$ 173

This includes the recognized portion of the total principal amount of financial assets which have been either securitized, used in an asset-backed financing arrangement, or similar transfer which are accounted for as sales and in which the transferor has continuing involvement with the assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets).

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)(3)

-URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107314-111719

+ Details

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

- Definition

This includes only the derecognized portion of the total principal amount of financial assets which have been either securitized, used in an asset-backed financing arrangement, or similar transfers which are accounted for as sales and in which the transferor has continuing involvement with the assets underlying the transaction (including, but not limited to, servicing, recourse, and restrictions on transferor's interests in transferred financial assets).

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)(2)

-URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107314-111719

+ Details

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

- Definition

The total principal outstanding of financial assets transferred in a securitization, asset-backed financing arrangement, or similar transfer that has been accounted for as sales and in which the transferor continues to have involvement, including both the derecognized and recognized portion of such transferred assets.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 860

-SubTopic 20

-Section 50

-Paragraph 4

-Subparagraph (a)(1)

-URI http://asc.fasb.org/extlink&oid=13989330&loc=d3e107314-111719

+ Details

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

- Details

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