Joint Ownership (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013
International Energy Brazil-Canoas I and II [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	47.20%	[1]
Property, plant, and equipment	$ 266	[1]
Accumulated depreciation	83	[1]
Construction work in progress	0	[1]
Duke Energy Carolinas [Member] | Duke Energy Carolinas Catawba Nuclear Station (Units 1 and 2) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	19.25%	[2],[3]
Property, plant, and equipment	887	[2],[3]
Accumulated depreciation	498	[2],[3]
Construction work in progress	0	[2],[3]
Duke Energy Progress [Member] | Duke Energy Progress Mayo Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	83.83%	[2],[4]
Property, plant, and equipment	856	[2],[4]
Accumulated depreciation	303	[2],[4]
Construction work in progress	104	[2],[4]
Duke Energy Progress [Member] | Shearon Harris Nuclear Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	83.83%	[2],[4]
Property, plant, and equipment	3,620	[2],[4]
Accumulated depreciation	2,018	[2],[4]
Construction work in progress	67	[2],[4]
Duke Energy Progress [Member] | Brunswick Nuclear Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	81.67%	[2],[4]
Property, plant, and equipment	1,921	[2],[4]
Accumulated depreciation	1,005	[2],[4]
Construction work in progress	176	[2],[4]
Duke Energy Progress [Member] | Duke Energy Progress Roxboro Station (Unit 4) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	87.06%	[2],[4]
Property, plant, and equipment	754	[2],[4]
Accumulated depreciation	473	[2],[4]
Construction work in progress	13	[2],[4]
Duke Energy Florida [Member] | Duke Energy Florida Crystal River Nuclear Station (Unit 3) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	91.78%	[2],[5]
Property, plant, and equipment	0	[2],[5]
Accumulated depreciation	0	[2],[5]
Construction work in progress	0	[2],[5]
Duke Energy Florida [Member] | Duke Energy Florida Intercession City Station (Unit P11) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	66.67%	[2],[6]
Property, plant, and equipment	25	[2],[6]
Accumulated depreciation	13	[2],[6]
Construction work in progress	0	[2],[6]
Duke Energy Ohio [Member] | Duke Energy Ohio Miami Fort Station (Units 7 and 8) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	64.00%	[7],[8]
Property, plant, and equipment	624	[7],[8]
Accumulated depreciation	232	[7],[8]
Construction work in progress	1	[7],[8]
Duke Energy Ohio [Member] | Duke Energy Ohio W.C. Beckjord Station (Unit 6) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	37.50%	[8],[9]
Property, plant, and equipment	0	[8],[9]
Accumulated depreciation	0	[8],[9]
Construction work in progress	0	[8],[9]
Duke Energy Ohio [Member] | Duke Energy Ohio J.M. Stuart Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	39.00%	[10],[8],[9]
Property, plant, and equipment	823	[10],[8],[9]
Accumulated depreciation	281	[10],[8],[9]
Construction work in progress	16	[10],[8],[9]
Duke Energy Ohio [Member] | Duke Energy Ohio Conesville Station (Unit 4) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	40.00%	[10],[8],[9]
Property, plant, and equipment	318	[10],[8],[9]
Accumulated depreciation	49	[10],[8],[9]
Construction work in progress	3	[10],[8],[9]
Duke Energy Ohio [Member] | Duke Energy Ohio W.M. Zimmer Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	46.50%	[8],[9]
Property, plant, and equipment	1,358	[8],[9]
Accumulated depreciation	574	[8],[9]
Construction work in progress	4	[8],[9]
Duke Energy Ohio [Member] | Duke Energy Ohio Killen Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	33.00%	[10],[7],[8]
Property, plant, and equipment	308	[10],[7],[8]
Accumulated depreciation	139	[10],[7],[8]
Construction work in progress	2	[10],[7],[8]
Duke Energy Ohio [Member] | Duke Energy Ohio Transmission [Member]
Jointly Owned Utility Plant Interests [Line Items]
Property, plant, and equipment	96	[2],[9]
Accumulated depreciation	49	[2],[9]
Construction work in progress	0	[2],[9]
Duke Energy Kentucky [Member] | Duke Energy Kentucky East Bend Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	69.00%	[2],[7]
Property, plant, and equipment	447	[2],[7]
Accumulated depreciation	240	[2],[7]
Construction work in progress	13	[2],[7]
Duke Energy Indiana [Member] | Vermillion Generation Station [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	62.50%	[11],[2]
Property, plant, and equipment	154	[11],[2]
Accumulated depreciation	61	[11],[2]
Construction work in progress	0	[11],[2]
Duke Energy Indiana [Member] | Duke Energy Indiana Gibson Station (Unit 5) [Member]
Jointly Owned Utility Plant Interests [Line Items]
Ownership share	50.05%	[12],[2]
Property, plant, and equipment	308	[12],[2]
Accumulated depreciation	160	[12],[2]
Construction work in progress	2	[12],[2]
Duke Energy Indiana [Member] | Duke Energy Indiana Transmission and local facilities [Member]
Jointly Owned Utility Plant Interests [Line Items]
Property, plant, and equipment	3,726	[12],[2]
Accumulated depreciation	1,582	[12],[2]
Construction work in progress	$ 0	[12],[2]

[1] Included in International Energy segment. Co-owned with Companhia Brasileira de Aluminio.

[2] Included in Regulated Utilities segment.

[3] Co-owned with North Carolina Municipal Power Agency Number 1, NCEMC and Piedmont Municipal Power Agency.

[4] Co-owned with North Carolina Eastern Municipal Power Agency.

[5] All costs associated with Crystal River Unit 3 are included within Regulatory assets on the Consolidated Balance Sheets of Duke Energy, Progress Energy and Duke Energy Florida. See Note 4 for additional information. Co-owned with Seminole Electric Cooperative, Inc., City of Ocala, Orlando Utilities Commission, City of Gainesville, City of Leesburg, Kissimmee Utility Authority, Utilities Commission of the City of New Smyrna Beach, City of Alachua and City of Bushnell.

[6] Co-owned with Georgia Power Company. Georgia Power Company has exclusive rights to the output of the unit during the months of June through September.

[7] Co-owned with The Dayton Power and Light Company.

[8] Included in Commercial Power segment.

[9] Co-owned with The Dayton Power and Light Company and Ohio Power Company.

[10] Station is not operated by Duke Energy Ohio.

[11] Co-owned with WVPA.

[12] Co-owned with WVPA and Indiana Municipal Power Agency.