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Investments in Debt and Equity Securities (Equity Securities, FV-NI - ASU 2016-01) (Details) $ in Millions | 3 Months Ended | 6 Months Ended
--- | --- | ---
Jun. 30, 2018 USD ($) | Jun. 30, 2018 USD ($)
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract] |  |
Equity Securities, FV-NI, Realized Gain | $ 47 | $ 66
Equity Securities, FV-NI, Realized Loss | 31 | 44
Ndtf [Member] |  |
EquitySecuritiesFvNiAccumulatedUnrealizedGainLoss [Abstract] |  |
Equity Securities, FV-NI, Unrealized Gain | 2,837 | 2,837
Equity Securities, FV-NI, Unrealized Loss | 40 | 40
Equity Securities, FV-NI | 4,988 | 4,988
Other Classification [Member] |  |
EquitySecuritiesFvNiAccumulatedUnrealizedGainLoss [Abstract] |  |
Equity Securities, FV-NI, Unrealized Gain | 46 | 46
Equity Securities, FV-NI | 109 | 109
Duke Energy Carolinas [Member] |  |
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract] |  |
Equity Securities, FV-NI, Realized Gain | 26 | 36
Equity Securities, FV-NI, Realized Loss | 17 | 22
Duke Energy Carolinas [Member] | Ndtf [Member] |  |
EquitySecuritiesFvNiAccumulatedUnrealizedGainLoss [Abstract] |  |
Equity Securities, FV-NI, Unrealized Gain | 1,544 | 1,544
Equity Securities, FV-NI, Unrealized Loss | 23 | 23
Equity Securities, FV-NI | 2,732 | 2,732
Progress Energy [Member] |  |
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract] |  |
Equity Securities, FV-NI, Realized Gain | 21 | 30
Equity Securities, FV-NI, Realized Loss | 14 | 22
Progress Energy [Member] | Ndtf [Member] |  |
EquitySecuritiesFvNiAccumulatedUnrealizedGainLoss [Abstract] |  |
Equity Securities, FV-NI, Unrealized Gain | 1,293 | 1,293
Equity Securities, FV-NI, Unrealized Loss | 17 | 17
Equity Securities, FV-NI | 2,256 | 2,256
Duke Energy Progress [Member] |  |
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract] |  |
Equity Securities, FV-NI, Realized Gain | 17 | 25
Equity Securities, FV-NI, Realized Loss | 12 | 20
Duke Energy Progress [Member] | Ndtf [Member] |  |
EquitySecuritiesFvNiAccumulatedUnrealizedGainLoss [Abstract] |  |
Equity Securities, FV-NI, Unrealized Gain | 995 | 995
Equity Securities, FV-NI, Unrealized Loss | 13 | 13
Equity Securities, FV-NI | 1,819 | 1,819
Duke Energy Florida [Member] |  |
Equity Securities, FV-NI, Realized Gain (Loss) [Abstract] |  |
Equity Securities, FV-NI, Realized Gain | 4 | 5
Equity Securities, FV-NI, Realized Loss | 2 | 2
Duke Energy Florida [Member] | Ndtf [Member] |  |
EquitySecuritiesFvNiAccumulatedUnrealizedGainLoss [Abstract] |  |
Equity Securities, FV-NI, Unrealized Gain | 298 | 298
Equity Securities, FV-NI, Unrealized Loss | 4 | 4
Equity Securities, FV-NI | 437 | 437
Duke Energy Indiana [Member] |  |
EquitySecuritiesFvNiAccumulatedUnrealizedGainLoss [Abstract] |  |
Equity Securities, FV-NI, Unrealized Gain | 36 | 36
Equity Securities, FV-NI | 74 | 74
Duke Energy Indiana [Member] | Other Classification [Member] |  |
EquitySecuritiesFvNiAccumulatedUnrealizedGainLoss [Abstract] |  |
Equity Securities, FV-NI | $ 74 | $ 74

X
- Definition Amount of accumulated unrealized gain on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Substantially all of the associated unrealized gains and losses on these investments are deferred as a regulatory asset or liability. + References No definition available. + Details
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- Definition Amount of accumulated unrealized loss on investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). Substantially all of the associated unrealized gains and losses on these investments are deferred as a regulatory asset or liability. + References No definition available. + Details
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- Definition Amount of investment in equity security measured at fair value with change in fair value recognized in net income (FV-NI). + References Reference 1: http://www.xbrl.org/2003/role/disclosureRef -Publisher FASB -Name Accounting Standards Codification -Topic 825 -SubTopic 10 -Section 45 -Paragraph 1A -URI http://asc.fasb.org/extlink&oid=99377092&loc=SL75136599-209740 + Details
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