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Committments and Contingencies (Schedule of Reserves and Insurance Recoveries) (Details) (USD $) In Millions, unless otherwise specified | Mar. 31, 2013 | Dec. 31, 2012
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Loss Contingencies [Line Items] |  |  |  |
Reserves for legal matters | $ 834 | [1],[2] | $ 846 | [1],[2]
Probable insurance recoveries | 781 | [3],[4] | 781 | [3],[4]
Duke Energy Carolinas [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Reserves for legal matters | 743 | [1],[2] | 751 | [1],[2]
Probable insurance recoveries | 781 | [3],[4] | 781 | [3],[4]
Progress Energy [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Reserves for legal matters | 75 | [1] | 79 | [1]
Duke Energy Progress [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Reserves for legal matters | 11 | [1] | 12 | [1]
Duke Energy Florida [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Reserves for legal matters | 44 | [1],[5] | 47 | [1],[5]
Duke Energy Indiana [Member] |  |  |  |
Loss Contingencies [Line Items] |  |  |  |
Reserves for legal matters | $ 7 | [1] | $ 8 | [1]
[1] | Reserves are classified in the respective Condensed Consolidated Balance Sheets in Other within Deferred Credits and Other Liabilities and Other within Current Liabilities.
[2] | Includes reserves for aforementioned asbestos-related injuries and damages claims.
[3] | Insurance recoveries are classified in the respective Condensed Consolidated Balance Sheets in Other within Investments and Other Assets and Receivables.
[4] | Relates to recoveries associated with aforementioned asbestos-related injuries and damages claims.
[5] | Includes workers' compensation claims.

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- Definition The carrying amount as of the balance sheet date of the combined total of loss contingency liabilities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 450 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6952336&loc=d3e14326-108349 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 5 -Paragraph 9, 10, 11, 12 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009.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
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- Definition The carrying amount as of the balance sheet date of a recorded receivable related to a loss contingency accrual. For example, an insurance recovery receivable to the extent that the insurance recovery is probable and does not exceed the amount of the loss previously recognized in the financial statements. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 5 -Paragraph 9 -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. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 460 -SubTopic 10 -Section 50 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=6851643&loc=d3e12053-110248 + Details
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