v3.3.0.814

Commitments and Contingencies (Schedule of Reserves) (Details) - USD ($) $ in Millions | Sep. 30, 2015 | Dec. 31, 2014
--- | --- | ---
Loss Contingencies [Line Items] |  |
Reserves for legal matters | $ 178 | $ 323
Duke Energy Carolinas [Member] |  |
Loss Contingencies [Line Items] |  |
Reserves for legal matters | 12 | 72
Progress Energy [Member] |  |
Loss Contingencies [Line Items] |  |
Reserves for legal matters | 74 | 93
Duke Energy Progress [Member] |  |
Loss Contingencies [Line Items] |  |
Reserves for legal matters | 17 | 37
Duke Energy Florida [Member] |  |
Loss Contingencies [Line Items] |  |
Reserves for legal matters | 36 | $ 36
Duke Energy Ohio [Member] |  |
Loss Contingencies [Line Items] |  |
Reserves for legal matters | $ 81 |

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