v2.4.0.8

Commitments and Contingencies (Narrative) (Details) (USD $) | 9 Months Ended | 0 Months Ended | 9 Months Ended |  |  | 0 Months Ended | 1 Months Ended |  | 9 Months Ended | 1 Months Ended |  |
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Sep. 30, 2014 Brazil Expansion Lawsuit [Member] | Sep. 30, 2014 Duke Energy Carolinas [Member] North Carolina Ash Basins [Member] Dan River [Member] | Feb. 21, 2014 Duke Energy Carolinas [Member] North Carolina Ash Basins [Member] Minimum [Member] Dan River [Member] gal T | Feb. 21, 2014 Duke Energy Carolinas [Member] North Carolina Ash Basins [Member] Maximum [Member] Dan River [Member] T gal | Sep. 30, 2014 Duke Energy Carolinas [Member] New Source Review Provisions Of Clean Air Act [Member] Claims plant project | Sep. 30, 2014 Duke Energy Carolinas [Member] Asbestos Issue [Member] | Dec. 31, 2013 Duke Energy Carolinas [Member] Asbestos Issue [Member] | Sep. 30, 2014 Duke Energy Carolinas [Member] Asbestos Issue [Member] Malignant Asbestos Claim [Member] Claims | Sep. 30, 2014 Duke Energy Carolinas [Member] Asbestos Issue [Member] Non Malignant Asbestos Claim [Member] Claims | Oct. 03, 2012 Progress Energy [Member] Synthetic Fuels [Member] | Dec. 31, 2009 Progress Energy [Member] Synthetic Fuels [Member] | Dec. 31, 2012 Progress Energy [Member] Synthetic Fuels [Member] | Sep. 30, 2014 Duke Energy Progress [Member] Spent Nuclear Fuels [Member] | Sep. 30, 2014 Duke Energy Florida [Member] Spent Nuclear Fuels [Member] | Mar. 31, 2014 Duke Energy Florida [Member] Westinghouse Electric Company Litigation [Member] | Mar. 28, 2014 Duke Energy Florida [Member] Westinghouse Electric Company Litigation [Member] | Dec. 11, 2012 Duke Energy Indiana [Member] Edwardsport IGCC Plant [Member]
Valuation and Qualifying Accounts [Abstract] |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Coal ash released, in tons |  |  | 30,000 | 39,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Basin water released, in gallons |  |  | 24,000,000 | 27,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |
Environmental remediation expense |  | $ 20,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Obligation to expand installed generation capacity, percent | 15.00% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Maximum civil penalties per day for each violation |  |  |  |  | 37,500 |  |  |  |  |  |  |  |  |  |  |  |
Projects with Alleged NSR Violations |  |  |  |  | 29 |  |  |  |  |  |  |  |  |  |  |  |
Number of Coal Plants with Alleged NSR Violations |  |  |  |  | 25 |  |  |  |  |  |  |  |  |  |  |  |
Number of Retired Plants |  |  |  |  | 11 |  |  |  |  |  |  |  |  |  |  |  |
Loss contingency, pending claims, number |  |  |  |  | 13 |  |  | 23 | 61 |  |  |  |  |  |  |  |
Remaining Number of Coal Plants with Alleged NSR Violations |  |  |  |  | 13 |  |  |  |  |  |  |  |  |  |  |  |
Asbestos-related injuries and damages reserves |  |  |  |  |  | 591,000,000 | 616,000,000 | 7,000,000 | 13,000,000 |  |  |  |  |  |  |  |
Reinsurance retention policy, amount retained |  |  |  |  |  | 476,000,000 |  |  |  |  |  |  |  |  |  |  |
Reinsurance retention policy, excess retention, amount reinsured |  |  |  |  |  | 864,000,000 |  |  |  |  |  |  |  |  |  |  |
Probable insurance recoveries |  |  |  |  |  | 616,000,000 | 649,000,000 |  |  |  |  |  |  |  |  |  |
Loss contingency, damages paid, value |  |  |  |  |  |  |  |  |  |  | 154,000,000 |  |  |  |  |  |
Damages awarded to plaintiff |  |  |  |  |  |  |  |  |  | 90,000,000 |  |  |  |  |  |  |
Gain recognized in period |  |  |  |  |  |  |  |  |  |  |  | 63,000,000 |  |  |  |  |
Gain (Loss) Related to Litigation Settlement |  |  |  |  |  |  |  |  |  |  |  |  | 83,000,000 | 21,000,000 |  |  |
Loss contingency, damages sought, value |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 510,000,000 |  |
Gain contingency, unrecorded amount |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 54,000,000 | $ 560,000,000

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- Definition The maximum per daily value (monetary amount) of the cival penalty the U.S. Department of Justice seeks for complaints and notices of violations under New Source Review (NSR) provisions of the Clean Air Act (CAA). + References No definition available. + Details
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- Definition Number of Coal Plants with Projects Alleged to have Violated the New Source Review provisions of the Clean Air Act + References No definition available. + Details
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- Definition The charge against earnings in the period for known or estimated future costs arising from requirements to perform environmental remediation activities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3602-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 410 -SubTopic 30 -Section 50 -Paragraph 12 -URI http://asc.fasb.org/extlink&oid=6393242&loc=d3e13296-110859 + Details
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- Definition Carrying amount as of the balance sheet date of reserves for the costs of settling insured claims and costs incurred in the claims settlement process attributable to asbestos and environmental claims, before estimated recoveries from reinsurers. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 40 -Section 50 -Paragraph 3 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=6482485&loc=d3e14764-158437 + Details
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