Merger Agreement	6 Months Ended
Jun. 30, 2011
Merger Agreement [Line Items]
Proposed Business Combination Disclosure Text Block	2. MERGER AGREEMENT On January 8, 2011, Duke Energy Corporation (Duke Energy) and Progress Energy entered into an Agreement and Plan of Merger (the Merger Agreement). Pursuant to the Merger Agreement, Progress Energy will be acquired by Duke Energy in a stock-for-stock transaction (the Merger) and continue as a wholly owned subsidiary of Duke Energy. Under the terms of the Merger Agreement, each share of Progress Energy common stock will be cancelled and converted into the right to receive 2.6125 shares of Duke Energy common stock. Each outstanding option to acquire, and each outstanding equity award relating to, one share of Progress Energy common stock will be converted into an option to acquire, or an equity award relating to, 2.6125 shares of Duke Energy common stock. The board of directors of Duke Energy approved a reverse stock split, at a ratio of 1-for-3, which will be subject to completion of the Merger and receipt of the requisite approval of the shareholders of Duke Energy. Accordingly, the adjusted exchange ratio is expected to be 0.87083 of a share of Duke Energy common stock, options and equity awards for each Progress Energy common share, option and equity award. Consummation of the Merger is subject to customary conditions, including, among others things, approval of the shareholders of each company, expiration or termination of the applicable Hart-Scott-Rodino Act waiting period, and receipt of approvals, to the extent required, from the FERC, the Federal Communications Commission, the NRC, the NCUC, the Kentucky Public Service Commission and the SCPSC. Although there are no merger-specific regulatory approvals required in Indiana, Ohio or Florida, the companies will continue to update the public service commissions in those states on the Merger, as applicable and as required. The status of these matters is as follows: On July 7, 2011, the SEC declared effective the registration statement on Form S-4 (the Registration Statement) containing a joint proxy statement for a special meeting of each company's shareholders to vote on the Merger. The joint proxy statement was mailed to shareholders of both companies beginning July 11, 2011. Shareholder meetings for Progress Energy and Duke Energy have been set for August 23, 2011. On March 28, 2011, Progress Energy and Duke Energy submitted their Hart-Scott-Rodino filing with the U.S. Department of Justice (DOJ) for review under U.S. antitrust laws. The 30-day waiting period required by the Hart-Scott-Rodino Act expired without Progress Energy or Duke Energy having received requests for additional information. Progress Energy and Duke Energy have met their obligations under the Hart-Scott-Rodino Act. On March 30, 2011, Progress Energy and Duke Energy made filings with the NRC for approval for transfer of control of licenses for Progress Energy's nuclear facilities to include Duke Energy as the ultimate parent corporation on these licenses. NRC approval is expected to take six to nine months. On April 4, 2011, Progress Energy and Duke Energy made joint filings with the FERC, which assesses market power-related issues. The first filing is a Joint Dispatch Agreement, pursuant to which PEC and Duke Energy Carolinas will agree to jointly dispatch their generation facilities in order to achieve certain of the operating efficiencies expected to result from the Merger. The second filing is a joint open access transmission tariff pursuant to which PEC and Duke Energy Carolinas will agree to provide transmission service over their transmission facilities under a single transmission rate. The intervention period at FERC expired June 3, 2011. On April 4, 2011, Progress Energy and Duke Energy filed a merger approval application and an application for approval of a Joint Dispatch Agreement between PEC and Duke Energy Carolinas with the NCUC. Procedural hearings have been scheduled for September 20, 2011. On April 25, 2011, Progress Energy and Duke Energy filed a merger-related filing and an application for approval of a Joint Dispatch Agreement between PEC and Duke Energy Carolinas with the SCPSC. Procedural hearings have not been scheduled. On July 27, 2011, the Federal Communications Commission approved the Assignment of Authorization filings to transfer control of certain licenses. On August 2, 2011, the Kentucky Public Service Commission approved Progress Energy and Duke Energy's merger-related settlement agreement with the Attorney General of the Commonwealth of Kentucky. The order approving the settlement agreement is subject to Progress Energy and Duke Energy's acceptance. Certain Progress Energy shareholders have filed class action lawsuits in the state and federal courts in North Carolina against Progress Energy and each of the members of Progress Energy's board of directors (See Note 13C). In connection with the Merger, we established an employee retention plan for certain eligible employees. Payments under the plan are contingent upon the consummation of the Merger and the employees' continued employment through a specified time period following the Merger. These payments will be recorded as compensation expense following consummation of the Merger. We estimate the costs of the retention plan to be $13 million. In connection with the Merger, we incurred merger and integration-related costs of $7 million and $21 million, net of tax, for the three and six months ended June 30, 2011, respectively. These costs are included in operation and maintenance (O&M) expense in our Consolidated Statements of Income. See Note 25 in the 2010 Form 10-K for additional information regarding the Merger.
PEC
Merger Agreement [Line Items]
Proposed Business Combination Disclosure Text Block	2. MERGER AGREEMENT On January 8, 2011, Duke Energy Corporation (Duke Energy) and Progress Energy entered into an Agreement and Plan of Merger (the Merger Agreement). Pursuant to the Merger Agreement, Progress Energy will be acquired by Duke Energy in a stock-for-stock transaction (the Merger) and continue as a wholly owned subsidiary of Duke Energy. Under the terms of the Merger Agreement, each share of Progress Energy common stock will be cancelled and converted into the right to receive 2.6125 shares of Duke Energy common stock. Each outstanding option to acquire, and each outstanding equity award relating to, one share of Progress Energy common stock will be converted into an option to acquire, or an equity award relating to, 2.6125 shares of Duke Energy common stock. The board of directors of Duke Energy approved a reverse stock split, at a ratio of 1-for-3, which will be subject to completion of the Merger and receipt of the requisite approval of the shareholders of Duke Energy. Accordingly, the adjusted exchange ratio is expected to be 0.87083 of a share of Duke Energy common stock, options and equity awards for each Progress Energy common share, option and equity award. Consummation of the Merger is subject to customary conditions, including, among others things, approval of the shareholders of each company, expiration or termination of the applicable Hart-Scott-Rodino Act waiting period, and receipt of approvals, to the extent required, from the FERC, the Federal Communications Commission, the NRC, the NCUC, the Kentucky Public Service Commission and the SCPSC. Although there are no merger-specific regulatory approvals required in Indiana, Ohio or Florida, the companies will continue to update the public service commissions in those states on the Merger, as applicable and as required. The status of these matters is as follows: On July 7, 2011, the SEC declared effective the registration statement on Form S-4 (the Registration Statement) containing a joint proxy statement for a special meeting of each company's shareholders to vote on the Merger. The joint proxy statement was mailed to shareholders of both companies beginning July 11, 2011. Shareholder meetings for Progress Energy and Duke Energy have been set for August 23, 2011. On March 28, 2011, Progress Energy and Duke Energy submitted their Hart-Scott-Rodino filing with the U.S. Department of Justice (DOJ) for review under U.S. antitrust laws. The 30-day waiting period required by the Hart-Scott-Rodino Act expired without Progress Energy or Duke Energy having received requests for additional information. Progress Energy and Duke Energy have met their obligations under the Hart-Scott-Rodino Act. On March 30, 2011, Progress Energy and Duke Energy made filings with the NRC for approval for transfer of control of licenses for Progress Energy's nuclear facilities to include Duke Energy as the ultimate parent corporation on these licenses. NRC approval is expected to take six to nine months. On April 4, 2011, Progress Energy and Duke Energy made joint filings with the FERC, which assesses market power-related issues. The first filing is a Joint Dispatch Agreement, pursuant to which PEC and Duke Energy Carolinas will agree to jointly dispatch their generation facilities in order to achieve certain of the operating efficiencies expected to result from the Merger. The second filing is a joint open access transmission tariff pursuant to which PEC and Duke Energy Carolinas will agree to provide transmission service over their transmission facilities under a single transmission rate. The intervention period at FERC expired June 3, 2011. On April 4, 2011, Progress Energy and Duke Energy filed a merger approval application and an application for approval of a Joint Dispatch Agreement between PEC and Duke Energy Carolinas with the NCUC. Procedural hearings have been scheduled for September 20, 2011. On April 25, 2011, Progress Energy and Duke Energy filed a merger-related filing and an application for approval of a Joint Dispatch Agreement between PEC and Duke Energy Carolinas with the SCPSC. Procedural hearings have not been scheduled. On July 27, 2011, the Federal Communications Commission approved the Assignment of Authorization filings to transfer control of certain licenses. On August 2, 2011, the Kentucky Public Service Commission approved Progress Energy and Duke Energy's merger-related settlement agreement with the Attorney General of the Commonwealth of Kentucky. The order approving the settlement agreement is subject to Progress Energy and Duke Energy's acceptance. Certain Progress Energy shareholders have filed class action lawsuits in the state and federal courts in North Carolina against Progress Energy and each of the members of Progress Energy's board of directors (See Note 13C). In connection with the Merger, we established an employee retention plan for certain eligible employees. Payments under the plan are contingent upon the consummation of the Merger and the employees' continued employment through a specified time period following the Merger. These payments will be recorded as compensation expense following consummation of the Merger. We estimate the costs of the retention plan to be $13 million. In connection with the Merger, we incurred merger and integration-related costs of $7 million and $21 million, net of tax, for the three and six months ended June 30, 2011, respectively. These costs are included in operation and maintenance (O&M) expense in our Consolidated Statements of Income. See Note 25 in the 2010 Form 10-K for additional information regarding the Merger.
PEF
Merger Agreement [Line Items]
Proposed Business Combination Disclosure Text Block	2. MERGER AGREEMENT On January 8, 2011, Duke Energy Corporation (Duke Energy) and Progress Energy entered into an Agreement and Plan of Merger (the Merger Agreement). Pursuant to the Merger Agreement, Progress Energy will be acquired by Duke Energy in a stock-for-stock transaction (the Merger) and continue as a wholly owned subsidiary of Duke Energy. Under the terms of the Merger Agreement, each share of Progress Energy common stock will be cancelled and converted into the right to receive 2.6125 shares of Duke Energy common stock. Each outstanding option to acquire, and each outstanding equity award relating to, one share of Progress Energy common stock will be converted into an option to acquire, or an equity award relating to, 2.6125 shares of Duke Energy common stock. The board of directors of Duke Energy approved a reverse stock split, at a ratio of 1-for-3, which will be subject to completion of the Merger and receipt of the requisite approval of the shareholders of Duke Energy. Accordingly, the adjusted exchange ratio is expected to be 0.87083 of a share of Duke Energy common stock, options and equity awards for each Progress Energy common share, option and equity award. Consummation of the Merger is subject to customary conditions, including, among others things, approval of the shareholders of each company, expiration or termination of the applicable Hart-Scott-Rodino Act waiting period, and receipt of approvals, to the extent required, from the FERC, the Federal Communications Commission, the NRC, the NCUC, the Kentucky Public Service Commission and the SCPSC. Although there are no merger-specific regulatory approvals required in Indiana, Ohio or Florida, the companies will continue to update the public service commissions in those states on the Merger, as applicable and as required. The status of these matters is as follows: On July 7, 2011, the SEC declared effective the registration statement on Form S-4 (the Registration Statement) containing a joint proxy statement for a special meeting of each company's shareholders to vote on the Merger. The joint proxy statement was mailed to shareholders of both companies beginning July 11, 2011. Shareholder meetings for Progress Energy and Duke Energy have been set for August 23, 2011. On March 28, 2011, Progress Energy and Duke Energy submitted their Hart-Scott-Rodino filing with the U.S. Department of Justice (DOJ) for review under U.S. antitrust laws. The 30-day waiting period required by the Hart-Scott-Rodino Act expired without Progress Energy or Duke Energy having received requests for additional information. Progress Energy and Duke Energy have met their obligations under the Hart-Scott-Rodino Act. On March 30, 2011, Progress Energy and Duke Energy made filings with the NRC for approval for transfer of control of licenses for Progress Energy's nuclear facilities to include Duke Energy as the ultimate parent corporation on these licenses. NRC approval is expected to take six to nine months. On April 4, 2011, Progress Energy and Duke Energy made joint filings with the FERC, which assesses market power-related issues. The first filing is a Joint Dispatch Agreement, pursuant to which PEC and Duke Energy Carolinas will agree to jointly dispatch their generation facilities in order to achieve certain of the operating efficiencies expected to result from the Merger. The second filing is a joint open access transmission tariff pursuant to which PEC and Duke Energy Carolinas will agree to provide transmission service over their transmission facilities under a single transmission rate. The intervention period at FERC expired June 3, 2011. On April 4, 2011, Progress Energy and Duke Energy filed a merger approval application and an application for approval of a Joint Dispatch Agreement between PEC and Duke Energy Carolinas with the NCUC. Procedural hearings have been scheduled for September 20, 2011. On April 25, 2011, Progress Energy and Duke Energy filed a merger-related filing and an application for approval of a Joint Dispatch Agreement between PEC and Duke Energy Carolinas with the SCPSC. Procedural hearings have not been scheduled. On July 27, 2011, the Federal Communications Commission approved the Assignment of Authorization filings to transfer control of certain licenses. On August 2, 2011, the Kentucky Public Service Commission approved Progress Energy and Duke Energy's merger-related settlement agreement with the Attorney General of the Commonwealth of Kentucky. The order approving the settlement agreement is subject to Progress Energy and Duke Energy's acceptance. Certain Progress Energy shareholders have filed class action lawsuits in the state and federal courts in North Carolina against Progress Energy and each of the members of Progress Energy's board of directors (See Note 13C). In connection with the Merger, we established an employee retention plan for certain eligible employees. Payments under the plan are contingent upon the consummation of the Merger and the employees' continued employment through a specified time period following the Merger. These payments will be recorded as compensation expense following consummation of the Merger. We estimate the costs of the retention plan to be $13 million. In connection with the Merger, we incurred merger and integration-related costs of $7 million and $21 million, net of tax, for the three and six months ended June 30, 2011, respectively. These costs are included in operation and maintenance (O&M) expense in our Consolidated Statements of Income. See Note 25 in the 2010 Form 10-K for additional information regarding the Merger.

Merger Agreement

6 Months Ended

Jun. 30, 2011

Proposed Business Combination Disclosure Text Block

2. MERGER AGREEMENT

On January 8, 2011, Duke Energy Corporation (Duke Energy) and Progress Energy entered into an Agreement and Plan of Merger (the Merger Agreement). Pursuant to the Merger Agreement, Progress Energy will be acquired by Duke Energy in a stock-for-stock transaction (the Merger) and continue as a wholly owned subsidiary of Duke Energy.

Under the terms of the Merger Agreement, each share of Progress Energy common stock will be cancelled and converted into the right to receive 2.6125 shares of Duke Energy common stock. Each outstanding option to acquire, and each outstanding equity award relating to, one share of Progress Energy common stock will be converted into an option to acquire, or an equity award relating to, 2.6125 shares of Duke Energy common stock. The board of directors of Duke Energy approved a reverse stock split, at a ratio of 1-for-3, which will be subject to completion of the Merger and receipt of the requisite approval of the shareholders of Duke Energy. Accordingly, the adjusted exchange ratio is expected to be 0.87083 of a share of Duke Energy common stock, options and equity awards for each Progress Energy common share, option and equity award.

Consummation of the Merger is subject to customary conditions, including, among others things, approval of the shareholders of each company, expiration or termination of the applicable Hart-Scott-Rodino Act waiting period, and receipt of approvals, to the extent required, from the FERC, the Federal Communications Commission, the NRC, the NCUC, the Kentucky Public Service Commission and the SCPSC. Although there are no merger-specific regulatory approvals required in Indiana, Ohio or Florida, the companies will continue to update the public service commissions in those states on the Merger, as applicable and as required. The status of these matters is as follows:

On July 7, 2011, the SEC declared effective the registration statement on Form S-4 (the Registration Statement) containing a joint proxy statement for a special meeting of each company's shareholders to vote on the Merger. The joint proxy statement was mailed to shareholders of both companies beginning July 11, 2011. Shareholder meetings for Progress Energy and Duke Energy have been set for August 23, 2011.
On March 28, 2011, Progress Energy and Duke Energy submitted their Hart-Scott-Rodino filing with the U.S. Department of Justice (DOJ) for review under U.S. antitrust laws. The 30-day waiting period required by the Hart-Scott-Rodino Act expired without Progress Energy or Duke Energy having received requests for additional information. Progress Energy and Duke Energy have met their obligations under the Hart-Scott-Rodino Act.
On March 30, 2011, Progress Energy and Duke Energy made filings with the NRC for approval for transfer of control of licenses for Progress Energy's nuclear facilities to include Duke Energy as the ultimate parent corporation on these licenses. NRC approval is expected to take six to nine months.
On April 4, 2011, Progress Energy and Duke Energy made joint filings with the FERC, which assesses market power-related issues. The first filing is a Joint Dispatch Agreement, pursuant to which PEC and Duke Energy Carolinas will agree to jointly dispatch their generation facilities in order to achieve certain of the operating efficiencies expected to result from the Merger. The second filing is a joint open access transmission tariff pursuant to which PEC and Duke Energy Carolinas will agree to provide transmission service over their transmission facilities under a single transmission rate. The intervention period at FERC expired June 3, 2011.
On April 4, 2011, Progress Energy and Duke Energy filed a merger approval application and an application for approval of a Joint Dispatch Agreement between PEC and Duke Energy Carolinas with the NCUC. Procedural hearings have been scheduled for September 20, 2011.
On April 25, 2011, Progress Energy and Duke Energy filed a merger-related filing and an application for approval of a Joint Dispatch Agreement between PEC and Duke Energy Carolinas with the SCPSC. Procedural hearings have not been scheduled.
On July 27, 2011, the Federal Communications Commission approved the Assignment of Authorization filings to transfer control of certain licenses.
On August 2, 2011, the Kentucky Public Service Commission approved Progress Energy and Duke Energy's merger-related settlement agreement with the Attorney General of the Commonwealth of Kentucky. The order approving the settlement agreement is subject to Progress Energy and Duke Energy's acceptance.

Certain Progress Energy shareholders have filed class action lawsuits in the state and federal courts in North Carolina against Progress Energy and each of the members of Progress Energy's board of directors (See Note 13C).

In connection with the Merger, we established an employee retention plan for certain eligible employees. Payments under the plan are contingent upon the consummation of the Merger and the employees' continued employment through a specified time period following the Merger. These payments will be recorded as compensation expense following consummation of the Merger. We estimate the costs of the retention plan to be $13 million.

In connection with the Merger, we incurred merger and integration-related costs of $7 million and $21 million, net of tax, for the three and six months ended June 30, 2011, respectively. These costs are included in operation and maintenance (O&M) expense in our Consolidated Statements of Income.

See Note 25 in the 2010 Form 10-K for additional information regarding the Merger.

PEC

Merger Agreement [Line Items]

Proposed Business Combination Disclosure Text Block

2. MERGER AGREEMENT

On July 7, 2011, the SEC declared effective the registration statement on Form S-4 (the Registration Statement) containing a joint proxy statement for a special meeting of each company's shareholders to vote on the Merger. The joint proxy statement was mailed to shareholders of both companies beginning July 11, 2011. Shareholder meetings for Progress Energy and Duke Energy have been set for August 23, 2011.
On March 28, 2011, Progress Energy and Duke Energy submitted their Hart-Scott-Rodino filing with the U.S. Department of Justice (DOJ) for review under U.S. antitrust laws. The 30-day waiting period required by the Hart-Scott-Rodino Act expired without Progress Energy or Duke Energy having received requests for additional information. Progress Energy and Duke Energy have met their obligations under the Hart-Scott-Rodino Act.
On March 30, 2011, Progress Energy and Duke Energy made filings with the NRC for approval for transfer of control of licenses for Progress Energy's nuclear facilities to include Duke Energy as the ultimate parent corporation on these licenses. NRC approval is expected to take six to nine months.
On April 4, 2011, Progress Energy and Duke Energy made joint filings with the FERC, which assesses market power-related issues. The first filing is a Joint Dispatch Agreement, pursuant to which PEC and Duke Energy Carolinas will agree to jointly dispatch their generation facilities in order to achieve certain of the operating efficiencies expected to result from the Merger. The second filing is a joint open access transmission tariff pursuant to which PEC and Duke Energy Carolinas will agree to provide transmission service over their transmission facilities under a single transmission rate. The intervention period at FERC expired June 3, 2011.
On April 4, 2011, Progress Energy and Duke Energy filed a merger approval application and an application for approval of a Joint Dispatch Agreement between PEC and Duke Energy Carolinas with the NCUC. Procedural hearings have been scheduled for September 20, 2011.
On April 25, 2011, Progress Energy and Duke Energy filed a merger-related filing and an application for approval of a Joint Dispatch Agreement between PEC and Duke Energy Carolinas with the SCPSC. Procedural hearings have not been scheduled.
On July 27, 2011, the Federal Communications Commission approved the Assignment of Authorization filings to transfer control of certain licenses.
On August 2, 2011, the Kentucky Public Service Commission approved Progress Energy and Duke Energy's merger-related settlement agreement with the Attorney General of the Commonwealth of Kentucky. The order approving the settlement agreement is subject to Progress Energy and Duke Energy's acceptance.

See Note 25 in the 2010 Form 10-K for additional information regarding the Merger.

PEF

Merger Agreement [Line Items]

Proposed Business Combination Disclosure Text Block

2. MERGER AGREEMENT

On July 7, 2011, the SEC declared effective the registration statement on Form S-4 (the Registration Statement) containing a joint proxy statement for a special meeting of each company's shareholders to vote on the Merger. The joint proxy statement was mailed to shareholders of both companies beginning July 11, 2011. Shareholder meetings for Progress Energy and Duke Energy have been set for August 23, 2011.
On March 28, 2011, Progress Energy and Duke Energy submitted their Hart-Scott-Rodino filing with the U.S. Department of Justice (DOJ) for review under U.S. antitrust laws. The 30-day waiting period required by the Hart-Scott-Rodino Act expired without Progress Energy or Duke Energy having received requests for additional information. Progress Energy and Duke Energy have met their obligations under the Hart-Scott-Rodino Act.
On March 30, 2011, Progress Energy and Duke Energy made filings with the NRC for approval for transfer of control of licenses for Progress Energy's nuclear facilities to include Duke Energy as the ultimate parent corporation on these licenses. NRC approval is expected to take six to nine months.
On April 4, 2011, Progress Energy and Duke Energy made joint filings with the FERC, which assesses market power-related issues. The first filing is a Joint Dispatch Agreement, pursuant to which PEC and Duke Energy Carolinas will agree to jointly dispatch their generation facilities in order to achieve certain of the operating efficiencies expected to result from the Merger. The second filing is a joint open access transmission tariff pursuant to which PEC and Duke Energy Carolinas will agree to provide transmission service over their transmission facilities under a single transmission rate. The intervention period at FERC expired June 3, 2011.
On April 4, 2011, Progress Energy and Duke Energy filed a merger approval application and an application for approval of a Joint Dispatch Agreement between PEC and Duke Energy Carolinas with the NCUC. Procedural hearings have been scheduled for September 20, 2011.
On April 25, 2011, Progress Energy and Duke Energy filed a merger-related filing and an application for approval of a Joint Dispatch Agreement between PEC and Duke Energy Carolinas with the SCPSC. Procedural hearings have not been scheduled.
On July 27, 2011, the Federal Communications Commission approved the Assignment of Authorization filings to transfer control of certain licenses.
On August 2, 2011, the Kentucky Public Service Commission approved Progress Energy and Duke Energy's merger-related settlement agreement with the Attorney General of the Commonwealth of Kentucky. The order approving the settlement agreement is subject to Progress Energy and Duke Energy's acceptance.

See Note 25 in the 2010 Form 10-K for additional information regarding the Merger.