Joint Ownership of Generating and Transmission Facilities Joint Ownership of Generating and Transmission Facilities (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014
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	$ 235
Accumulated depreciation	78
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	886
Accumulated depreciation	534
Construction work in progress	29
Duke Energy Progress [Member] \| Duke Energy Progress Mayo Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	83.83%
Property, plant, and equipment	1,111
Accumulated depreciation	360
Construction work in progress	10
Duke Energy Progress [Member] \| Shearon Harris Nuclear Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	83.83%
Property, plant, and equipment	3,872
Accumulated depreciation	2,242
Construction work in progress	208
Duke Energy Progress [Member] \| Brunswick Nuclear Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	81.67%
Property, plant, and equipment	2,673
Accumulated depreciation	1,372
Construction work in progress	290
Duke Energy Progress [Member] \| Duke Energy Progress Roxboro Station (Unit 4) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	87.06%
Property, plant, and equipment	954
Accumulated depreciation	514
Construction work in progress	24
Duke Energy Florida [Member] \| Duke Energy Florida Crystal River Nuclear Station (Unit 3) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	91.78%
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	14
Duke Energy Ohio [Member] \| Duke Energy Ohio Miami Fort Station (Units 7 and 8) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	64.00%
Duke Energy Ohio [Member] \| Duke Energy Ohio J.M. Stuart Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	39.00%
Duke Energy Ohio [Member] \| Duke Energy Ohio Conesville Station (Unit 4) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	40.00%
Duke Energy Ohio [Member] \| Duke Energy Ohio W.M. Zimmer Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	46.50%
Duke Energy Ohio [Member] \| Duke Energy Ohio Killen Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Joint owner ownership percentage	33.00%
Duke Energy Ohio [Member] \| Duke Energy Ohio Transmission [Member]
Jointly Owned Utility Plant Interests [Line Items]
Property, plant, and equipment	96
Accumulated depreciation	51
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	315
Accumulated depreciation	170
Construction work in progress	6
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	154
Accumulated depreciation	105
Duke Energy Indiana [Member] \| Duke Energy Indiana Transmission and local facilities [Member]
Jointly Owned Utility Plant Interests [Line Items]
Property, plant, and equipment	3,918
Accumulated depreciation	$ 1,633

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

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- Definition

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

+ References

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- Definition

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

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- Definition

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

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