Joint Ownership of Generating and Transmission Facilities (Schedule Joint Ownership of Generating and Transmission Facilities) (Details) $ in Millions	Dec. 31, 2018 USD ($)
Duke Energy Carolinas [Member] \| Catawba (Units 1 and 2) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership interest	19.25%
Property, plant, and equipment	$ 989
Accumulated depreciation	483
Construction work in progress	$ 17
Duke Energy Carolinas [Member] \| W.S. Lee CC [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership interest	86.67%
Property, plant, and equipment	$ 593
Accumulated depreciation	12
Construction work in progress	$ 4
Duke Energy Indiana [Member] \| Gibson Station (Unit 5) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership interest	50.05%
Property, plant, and equipment	$ 390
Accumulated depreciation	173
Construction work in progress	$ 3
Duke Energy Indiana [Member] \| Vermillion Generation Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership interest	62.50%
Property, plant, and equipment	$ 168
Accumulated depreciation	135
Duke Energy Indiana [Member] \| Transmission and local facilities [Member]
Jointly Owned Utility Plant Interests [Line Items]
Property, plant, and equipment	5,037
Accumulated depreciation	$ 1,769

The period end amount owned by the reporting utility of a jointly owned utility plant in service.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-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=115995737&loc=d3e659983-123033

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- 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

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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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