v2.4.0.6

Risk Management, Derivative Instruments And Hedging Activities (Narrative) (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended |
--- | --- | ---
Mar. 31, 2013 | Mar. 31, 2012
Derivative [Line Items] |  |
Pre-tax deferred losses related to Effective Cash Flow Hedges | $ 144 | $ 102
Amount expected to be Recognized in earnings during the next 12 months | 4 |
Progress Energy [Member] |  |
Derivative [Line Items] |  |
Pre-tax deferred losses related to Effective Cash Flow Hedges | 68 | 226
Amount expected to be Recognized in earnings during the next 12 months | 5 |
Duke Energy Progress [Member] |  |
Derivative [Line Items] |  |
Pre-tax deferred losses related to Effective Cash Flow Hedges |  | 109
Duke Energy Florida [Member] |  |
Derivative [Line Items] |  |
Pre-tax deferred losses related to Effective Cash Flow Hedges |  | $ 42

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- Definition Amount of unrealized (gain) loss pre-tax related to the (increase) decrease in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective. + References No definition available. + Details
Name: | duk_UnrealizedGainLossOnInterestRateCashFlowHedgesPreTaxAccumulatedOtherComprehensiveIncomeOrLoss
Namespace Prefix: | duk_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

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- Definition The estimated net amount of existing gains or losses on cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=7668309&loc=d3e80748-113994 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 133 -Paragraph 45 -Subparagraph b(2) -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. + Details
Name: | us-gaap_CashFlowHedgeGainLossToBeReclassifiedWithinTwelveMonths
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration

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- Details
Name: | us-gaap_DerivativeLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration