Organization And Basis of Presentation (Policy)	6 Months Ended
Jun. 30, 2012
Organization	Organization. Duke Energy Corporation (collectively with its subsidiaries, Duke Energy) is an energy company headquartered in Charlotte, North Carolina. Duke Energy operates in the United States (U.S.) primarily through its direct and indirect wholly owned subsidiaries, Duke Energy Carolinas, LLC (Duke Energy Carolinas), Duke Energy Ohio, Inc. (Duke Energy Ohio), which includes Duke Energy Kentucky, Inc. (Duke Energy Kentucky), and Duke Energy Indiana, Inc. (Duke Energy Indiana), as well as in Latin America through International Energy. When discussing Duke Energy's condensed consolidated financial information, it necessarily includes the results of its three separate subsidiary registrants, Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana (collectively referred to as the Subsidiary Registrants), which, along with Duke Energy, are collectively referred to as the Duke Energy Registrants. The information in these combined notes relates to each of the Duke Energy Registrants as noted in the Index to the Combined Notes. However, none of the registrants makes any representation as to information related solely to Duke Energy or the subsidiaries of Duke Energy other than itself. As discussed further in Note 3, Duke Energy operates in three reportable business segments: U.S. Franchised Electric and Gas, Commercial Power and International Energy. The remainder of Duke Energy's operations is presented as Other. These Unaudited Condensed Consolidated Financial Statements include, after eliminating intercompany transactions and balances, the accounts of the Duke Energy Registrants and all majority-owned subsidiaries where the respective Duke Energy Registrants have control and those variable interest entities (VIEs) where the respective Duke Energy Registrants are the primary beneficiary. These Unaudited Condensed Consolidated Financial Statements also reflect Duke Energy Carolinas' approximate 19.25% proportionate share of the Catawba Nuclear Station, as well as Duke Energy Ohio's proportionate share of certain generation and transmission facilities in Ohio, Indiana and Kentucky and Duke Energy Indiana's proportionate share of certain generation and transmission facilities. In January 2012, Duke Energy Ohio completed the sale of its 75% ownership of the Vermillion Generating Station; upon the close, Duke Energy Indiana purchased a 62.5% interest in the station. See Note 2 for further discussion. Duke Energy Carolinas, a wholly owned subsidiary of Duke Energy, is an electric utility company that generates, transmits, distributes and sells electricity in North Carolina and South Carolina. Duke Energy Carolinas is subject to the regulatory provisions of the North Carolina Utilities Commission (NCUC), the Public Service Commission of South Carolina (PSCSC), the U.S. Nuclear Regulatory Commission (NRC) and the Federal Energy Regulatory Commission (FERC). Substantially all of Duke Energy Carolinas' operations are regulated and qualify for regulatory accounting treatment. As discussed further in Note 3, Duke Energy Carolinas' operations include one reportable business segment, Franchised Electric. Duke Energy Ohio is an indirect wholly owned subsidiary of Duke Energy. Duke Energy Ohio is a combination electric and gas public utility that provides service in the southwestern portion of Ohio and in northern Kentucky through its wholly owned subsidiary Duke Energy Kentucky, as well as electric generation in parts of Ohio, Illinois and Pennsylvania. Duke Energy Ohio's principal lines of business include generation, transmission and distribution of electricity, the sale of and/or transportation of natural gas, and energy marketing. Duke Energy Ohio conducts competitive auctions for retail electricity supply in Ohio whereby the energy price is recovered from retail customers. Duke Energy Kentucky's principal lines of business include generation, transmission and distribution of electricity, as well as the sale of and/or transportation of natural gas. Duke Energy Ohio is subject to the regulatory provisions of the Public Utilities Commission of Ohio (PUCO), the Kentucky Public Service Commission (KPSC) and the FERC. Duke Energy Ohio applies regulatory accounting treatment to substantially all of the operations of its Franchised Electric and Gas operating segment. Through November 2011, Duke Energy Ohio applied regulatory accounting treatment to certain rate riders associated with retail generation of its Commercial Power operating segment. See Note 3 for information about business segments. Duke Energy Indiana is an indirect wholly owned subsidiary of Duke Energy. Duke Energy Indiana is an electric utility that provides service in north central, central, and southern Indiana. Its primary line of business is generation, transmission and distribution of electricity. Duke Energy Indiana is subject to the regulatory provisions of the Indiana Utility Regulatory Commission (IURC) and the FERC. The substantial majority of Duke Energy Indiana's operations are regulated and qualify for regulatory accounting treatment. As discussed further in Note 3, Duke Energy Indiana's operations include one reportable business segment, Franchised Electric. See Note 2 for information regarding Duke Energy's merger with Progress Energy, Inc. (Progress Energy) that closed on July 2, 2012. For the periods presented, Duke Energy's condensed consolidated financial information does not include the results of Progress Energy and its registrants. Also, the Duke Energy Registrants, as defined above, does not include Progress Energy, Inc., Progress Energy Carolinas or Progress Energy Florida, unless otherwise noted.
Use Of Estimates	Use of Estimates. To conform to GAAP in the U.S., management makes estimates and assumptions that affect the amounts reported in the Unaudited Condensed Consolidated Financial Statements and Notes. Although these estimates are based on management's best available information at the time, actual results could differ.
Unbilled Revenue	Unbilled Revenue. Revenues on sales of electricity and gas are recognized when either the service is provided or the product is delivered. Unbilled retail revenues are estimated by applying average revenue per kilowatt-hour or per thousand cubic feet (Mcf) for all customer classes to the number of estimated kilowatt-hours or Mcfs delivered but not billed. Unbilled wholesale energy revenues are calculated by applying the contractual rate per megawatt-hour (MWh) to the number of estimated MWh delivered but not yet billed. Unbilled wholesale demand revenues are calculated by applying the contractual rate per megawatt (MW) to the MW volume delivered but not yet billed. The amount of unbilled revenues can vary significantly from period to period as a result of numerous factors, including seasonality, weather, customer usage patterns and customer mix.
Basis Of Presentation	Basis of Presentation. These Unaudited Condensed Consolidated Financial Statements have been prepared in accordance with generally accepted accounting principles (GAAP) in the U.S. for interim financial information and with the instructions to Form 10-Q and Regulation S-X. Accordingly, these Unaudited Condensed Consolidated Financial Statements do not include all of the information and notes required by GAAP in the U.S. for annual financial statements. Because the interim Unaudited Condensed Consolidated Financial Statements and Notes do not include all of the information and notes required by GAAP in the U.S. for annual financial statements, the Unaudited Condensed Consolidated Financial Statements and other information included in this quarterly report should be read in conjunction with the respective Consolidated Financial Statements and Notes in the Duke Energy Registrants combined Form 10-K for the year ended December 31, 2011. These Unaudited Condensed Consolidated Financial Statements reflect all normal recurring adjustments that are, in the opinion of the respective companies' management, necessary to fairly present the financial position and results of operations of each Duke Energy Registrant. Amounts reported in Duke Energy's interim Unaudited Condensed Consolidated Statements of Operations and each of the Subsidiary Registrants' interim Unaudited Condensed Consolidated Statements of Income and Comprehensive Income are not necessarily indicative of amounts expected for the respective annual periods due to the effects of seasonal temperature variations on energy consumption, regulatory rulings, the timing of maintenance on electric generating units, changes in mark-to-market valuations, changing commodity prices and other factors. Duke Energy Ohio and Duke Energy Indiana sell power to and purchase power from PJM Interconnection, LLC (PJM) and Midwest Independent Transmission System Operator, Inc. (MISO), respectively. Duke Energy Ohio and Duke Energy Indiana account for these transactions on a net hourly basis as the transactions are settled on a net hourly basis.

Organization And Basis of Presentation (Policy)

6 Months Ended

Jun. 30, 2012

Organization. Duke Energy Corporation (collectively with its subsidiaries, Duke Energy) is an energy company headquartered in Charlotte, North Carolina. Duke Energy operates in the United States (U.S.) primarily through its direct and indirect wholly owned subsidiaries, Duke Energy Carolinas, LLC (Duke Energy Carolinas), Duke Energy Ohio, Inc. (Duke Energy Ohio), which includes Duke Energy Kentucky, Inc. (Duke Energy Kentucky), and Duke Energy Indiana, Inc. (Duke Energy Indiana), as well as in Latin America through International Energy. When discussing Duke Energy's condensed consolidated financial information, it necessarily includes the results of its three separate subsidiary registrants, Duke Energy Carolinas, Duke Energy Ohio and Duke Energy Indiana (collectively referred to as the Subsidiary Registrants), which, along with Duke Energy, are collectively referred to as the Duke Energy Registrants. The information in these combined notes relates to each of the Duke Energy Registrants as noted in the Index to the Combined Notes. However, none of the registrants makes any representation as to information related solely to Duke Energy or the subsidiaries of Duke Energy other than itself. As discussed further in Note 3, Duke Energy operates in three reportable business segments: U.S. Franchised Electric and Gas, Commercial Power and International Energy. The remainder of Duke Energy's operations is presented as Other.

These Unaudited Condensed Consolidated Financial Statements include, after eliminating intercompany transactions and balances, the accounts of the Duke Energy Registrants and all majority-owned subsidiaries where the respective Duke Energy Registrants have control and those variable interest entities (VIEs) where the respective Duke Energy Registrants are the primary beneficiary. These Unaudited Condensed Consolidated Financial Statements also reflect Duke Energy Carolinas' approximate 19.25% proportionate share of the Catawba Nuclear Station, as well as Duke Energy Ohio's proportionate share of certain generation and transmission facilities in Ohio, Indiana and Kentucky and Duke Energy Indiana's proportionate share of certain generation and transmission facilities. In January 2012, Duke Energy Ohio completed the sale of its 75% ownership of the Vermillion Generating Station; upon the close, Duke Energy Indiana purchased a 62.5% interest in the station. See Note 2 for further discussion.

Duke Energy Carolinas, a wholly owned subsidiary of Duke Energy, is an electric utility company that generates, transmits, distributes and sells electricity in North Carolina and South Carolina. Duke Energy Carolinas is subject to the regulatory provisions of the North Carolina Utilities Commission (NCUC), the Public Service Commission of South Carolina (PSCSC), the U.S. Nuclear Regulatory Commission (NRC) and the Federal Energy Regulatory Commission (FERC). Substantially all of Duke Energy Carolinas' operations are regulated and qualify for regulatory accounting treatment. As discussed further in Note 3, Duke Energy Carolinas' operations include one reportable business segment, Franchised Electric.

Duke Energy Ohio is an indirect wholly owned subsidiary of Duke Energy. Duke Energy Ohio is a combination electric and gas public utility that provides service in the southwestern portion of Ohio and in northern Kentucky through its wholly owned subsidiary Duke Energy Kentucky, as well as electric generation in parts of Ohio, Illinois and Pennsylvania. Duke Energy Ohio's principal lines of business include generation, transmission and distribution of electricity, the sale of and/or transportation of natural gas, and energy marketing. Duke Energy Ohio conducts competitive auctions for retail electricity supply in Ohio whereby the energy price is recovered from retail customers. Duke Energy Kentucky's principal lines of business include generation, transmission and distribution of electricity, as well as the sale of and/or transportation of natural gas. Duke Energy Ohio is subject to the regulatory provisions of the Public Utilities Commission of Ohio (PUCO), the Kentucky Public Service Commission (KPSC) and the FERC. Duke Energy Ohio applies regulatory accounting treatment to substantially all of the operations of its Franchised Electric and Gas operating segment. Through November 2011, Duke Energy Ohio applied regulatory accounting treatment to certain rate riders associated with retail generation of its Commercial Power operating segment. See Note 3 for information about business segments.

Duke Energy Indiana is an indirect wholly owned subsidiary of Duke Energy. Duke Energy Indiana is an electric utility that provides service in north central, central, and southern Indiana. Its primary line of business is generation, transmission and distribution of electricity. Duke Energy Indiana is subject to the regulatory provisions of the Indiana Utility Regulatory Commission (IURC) and the FERC. The substantial majority of Duke Energy Indiana's operations are regulated and qualify for regulatory accounting treatment. As discussed further in Note 3, Duke Energy Indiana's operations include one reportable business segment, Franchised Electric.

See Note 2 for information regarding Duke Energy's merger with Progress Energy, Inc. (Progress Energy) that closed on July 2, 2012. For the periods presented, Duke Energy's condensed consolidated financial information does not include the results of Progress Energy and its registrants. Also, the Duke Energy Registrants, as defined above, does not include Progress Energy, Inc., Progress Energy Carolinas or Progress Energy Florida, unless otherwise noted.

Use Of Estimates

Use of Estimates. To conform to GAAP in the U.S., management makes estimates and assumptions that affect the amounts reported in the Unaudited Condensed Consolidated Financial Statements and Notes. Although these estimates are based on management's best available information at the time, actual results could differ.

Unbilled Revenue

Unbilled Revenue. Revenues on sales of electricity and gas are recognized when either the service is provided or the product is delivered. Unbilled retail revenues are estimated by applying average revenue per kilowatt-hour or per thousand cubic feet (Mcf) for all customer classes to the number of estimated kilowatt-hours or Mcfs delivered but not billed. Unbilled wholesale energy revenues are calculated by applying the contractual rate per megawatt-hour (MWh) to the number of estimated MWh delivered but not yet billed. Unbilled wholesale demand revenues are calculated by applying the contractual rate per megawatt (MW) to the MW volume delivered but not yet billed. The amount of unbilled revenues can vary significantly from period to period as a result of numerous factors, including seasonality, weather, customer usage patterns and customer mix.

Basis Of Presentation

Basis of Presentation. These Unaudited Condensed Consolidated Financial Statements have been prepared in accordance with generally accepted accounting principles (GAAP) in the U.S. for interim financial information and with the instructions to Form 10-Q and Regulation S-X. Accordingly, these Unaudited Condensed Consolidated Financial Statements do not include all of the information and notes required by GAAP in the U.S. for annual financial statements. Because the interim Unaudited Condensed Consolidated Financial Statements and Notes do not include all of the information and notes required by GAAP in the U.S. for annual financial statements, the Unaudited Condensed Consolidated Financial Statements and other information included in this quarterly report should be read in conjunction with the respective Consolidated Financial Statements and Notes in the Duke Energy Registrants combined Form 10-K for the year ended December 31, 2011.

These Unaudited Condensed Consolidated Financial Statements reflect all normal recurring adjustments that are, in the opinion of the respective companies' management, necessary to fairly present the financial position and results of operations of each Duke Energy Registrant. Amounts reported in Duke Energy's interim Unaudited Condensed Consolidated Statements of Operations and each of the Subsidiary Registrants' interim Unaudited Condensed Consolidated Statements of Income and Comprehensive Income are not necessarily indicative of amounts expected for the respective annual periods due to the effects of seasonal temperature variations on energy consumption, regulatory rulings, the timing of maintenance on electric generating units, changes in mark-to-market valuations, changing commodity prices and other factors.

Duke Energy Ohio and Duke Energy Indiana sell power to and purchase power from PJM Interconnection, LLC (PJM) and Midwest Independent Transmission System Operator, Inc. (MISO), respectively. Duke Energy Ohio and Duke Energy Indiana account for these transactions on a net hourly basis as the transactions are settled on a net hourly basis.

- Definition

Disclosure of accounting policy for revenue recognition. If the entity has different policies for different types of revenue transactions, the policy for each material type of transaction is generally disclosed. If a sales transaction has multiple element arrangements (for example, delivery of multiple products, services or the rights to use assets) the disclosure may indicate the accounting policy for each unit of accounting as well as how units of accounting are determined and valued. The disclosure may encompass important judgment as to appropriateness of principles related to recognition of revenue. The disclosure also may indicate the entity's treatment of any unearned or deferred revenue that arises from the transaction.

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- Definition

Disclosure of accounting policy for the use of estimates in the preparation of financial statements in conformity with generally accepted accounting principles.

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