Variable Interest Entities (Receivables Sold)(Details) (Cinergy Receivables [Member], USD $) In Millions, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012
Duke Energy Ohio [Member]
Variable Interest Entity [Line Items]
Receivables sold	$ 257	$ 282
Less: retained interests	82	97
Net receivables sold	175	185
Duke Energy Indiana [Member]
Variable Interest Entity [Line Items]
Receivables sold	312	289
Less: retained interests	110	116
Net receivables sold	$ 202	$ 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).

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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).

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- 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.

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