v2.4.0.8

Investments in Debt and Equity Securities (Available-For-Sale Investments) (Details) (USD $) In Millions, unless otherwise specified | Sep. 30, 2014 | Dec. 31, 2013
--- | --- | ---
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | $ 2,011 |  | $ 1,884 |
Gross Unrealized Holding Losses | 42 |  | 47 |
Estimated Fair Value | 5,747 |  | 5,551 |
Ndtf [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 1,973 |  | 1,852 |
Gross Unrealized Holding Losses | 37 |  | 36 |
Estimated Fair Value | 5,374 |  | 5,133 |
Ndtf [Member] | Cash and Cash Equivalents [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 74 |  | 110 |
Ndtf [Member] | Equity Securities [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 1,943 |  | 1,813 |
Gross Unrealized Holding Losses | 28 |  | 10 |
Estimated Fair Value | 3,825 |  | 3,579 |
Ndtf [Member] | Corporate Debt Securities [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 13 |  | 8 |
Gross Unrealized Holding Losses | 3 |  | 6 |
Estimated Fair Value | 493 |  | 400 |
Ndtf [Member] | Municipal Bonds [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 5 |  | 2 |
Gross Unrealized Holding Losses | 1 |  | 6 |
Estimated Fair Value | 132 |  | 160 |
Ndtf [Member] | US Treasury and Government [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 12 |  | 7 |
Gross Unrealized Holding Losses | 4 |  | 12 |
Estimated Fair Value | 713 |  | 730 |
Ndtf [Member] | Other Debt Obligations [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  | 22 |
Gross Unrealized Holding Losses | 1 |  | 2 |
Estimated Fair Value | 137 |  | 154 |
Other Classification [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 38 | [1] | 32 | [1]
Gross Unrealized Holding Losses | 5 | [1] | 11 | [1]
Estimated Fair Value | 373 | [1] | 418 | [1]
Other Classification [Member] | Cash and Cash Equivalents [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 16 |  | 21 |
Other Classification [Member] | Equity Securities [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 32 |  | 29 |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 95 |  | 91 |
Other Classification [Member] | Corporate Debt Securities [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 2 |  | 1 |
Gross Unrealized Holding Losses |  |  | 1 |
Estimated Fair Value | 68 |  | 99 |
Other Classification [Member] | Municipal Bonds [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 3 |  | 2 |
Gross Unrealized Holding Losses |  |  | 2 |
Estimated Fair Value | 82 |  | 79 |
Other Classification [Member] | US Treasury and Government [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 16 |  | 17 |
Other Classification [Member] | Other Debt Obligations [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 1 |  |  |
Gross Unrealized Holding Losses | 5 |  | 8 |
Estimated Fair Value | 96 |  | 111 |
Duke Energy Carolinas [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 1,058 |  | 1,004 |
Gross Unrealized Holding Losses | 24 |  | 23 |
Estimated Fair Value | 2,972 |  | 2,837 |
Duke Energy Carolinas [Member] | Ndtf [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 1,058 |  | 1,004 |
Gross Unrealized Holding Losses | 23 |  | 22 |
Estimated Fair Value | 2,969 |  | 2,834 |
Duke Energy Carolinas [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 39 |  | 42 |
Duke Energy Carolinas [Member] | Ndtf [Member] | Equity Securities [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 1,046 |  | 974 |
Gross Unrealized Holding Losses | 17 |  | 6 |
Estimated Fair Value | 2,124 |  | 1,964 |
Duke Energy Carolinas [Member] | Ndtf [Member] | Corporate Debt Securities [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 7 |  | 5 |
Gross Unrealized Holding Losses | 3 |  | 5 |
Estimated Fair Value | 345 |  | 274 |
Duke Energy Carolinas [Member] | Ndtf [Member] | Municipal Bonds [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 1 |  |  |
Gross Unrealized Holding Losses |  |  | 2 |
Estimated Fair Value | 22 |  | 54 |
Duke Energy Carolinas [Member] | Ndtf [Member] | US Treasury and Government [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 4 |  | 3 |
Gross Unrealized Holding Losses | 2 |  | 7 |
Estimated Fair Value | 317 |  | 354 |
Duke Energy Carolinas [Member] | Ndtf [Member] | Other Debt Obligations [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  | 22 |
Gross Unrealized Holding Losses | 1 |  | 2 |
Estimated Fair Value | 122 |  | 146 |
Duke Energy Carolinas [Member] | Other Classification [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  | [1]
Gross Unrealized Holding Losses | 1 | [1] | 1 | [1]
Estimated Fair Value | 3 | [1] | 3 | [1]
Duke Energy Carolinas [Member] | Other Classification [Member] | Other Debt Obligations [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses | 1 |  | 1 |
Estimated Fair Value | 3 |  | 3 |
Progress Energy [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 918 |  | 849 |
Gross Unrealized Holding Losses | 14 |  | 14 |
Estimated Fair Value | 2,463 |  | 2,358 |
Progress Energy [Member] | Ndtf [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 915 |  | 848 |
Gross Unrealized Holding Losses | 14 |  | 14 |
Estimated Fair Value | 2,405 |  | 2,299 |
Progress Energy [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 35 |  | 68 |
Progress Energy [Member] | Ndtf [Member] | Equity Securities [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 897 |  | 839 |
Gross Unrealized Holding Losses | 11 |  | 4 |
Estimated Fair Value | 1,701 |  | 1,615 |
Progress Energy [Member] | Ndtf [Member] | Corporate Debt Securities [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 6 |  | 3 |
Gross Unrealized Holding Losses |  |  | 1 |
Estimated Fair Value | 148 |  | 126 |
Progress Energy [Member] | Ndtf [Member] | Municipal Bonds [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 4 |  | 2 |
Gross Unrealized Holding Losses | 1 |  | 4 |
Estimated Fair Value | 110 |  | 106 |
Progress Energy [Member] | Ndtf [Member] | US Treasury and Government [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 8 |  | 4 |
Gross Unrealized Holding Losses | 2 |  | 5 |
Estimated Fair Value | 396 |  | 376 |
Progress Energy [Member] | Ndtf [Member] | Other Debt Obligations [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 15 |  | 8 |
Progress Energy [Member] | Other Classification [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 3 | [1] | 1 | [1]
Gross Unrealized Holding Losses |  | [1] |  | [1]
Estimated Fair Value | 58 | [1] | 59 | [1]
Progress Energy [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 15 |  | 20 |
Progress Energy [Member] | Other Classification [Member] | Municipal Bonds [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 3 |  | 1 |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 43 |  | 39 |
Duke Energy Progress [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 588 |  | 544 |
Gross Unrealized Holding Losses | 10 |  | 11 |
Estimated Fair Value | 1,625 |  | 1,540 |
Duke Energy Progress [Member] | Ndtf [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 588 |  | 544 |
Gross Unrealized Holding Losses | 10 |  | 11 |
Estimated Fair Value | 1,623 |  | 1,538 |
Duke Energy Progress [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 28 |  | 48 |
Duke Energy Progress [Member] | Ndtf [Member] | Equity Securities [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 574 |  | 535 |
Gross Unrealized Holding Losses | 7 |  | 3 |
Estimated Fair Value | 1,127 |  | 1,069 |
Duke Energy Progress [Member] | Ndtf [Member] | Corporate Debt Securities [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 4 |  | 3 |
Gross Unrealized Holding Losses |  |  | 1 |
Estimated Fair Value | 95 |  | 80 |
Duke Energy Progress [Member] | Ndtf [Member] | Municipal Bonds [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 4 |  | 2 |
Gross Unrealized Holding Losses | 1 |  | 4 |
Estimated Fair Value | 108 |  | 104 |
Duke Energy Progress [Member] | Ndtf [Member] | US Treasury and Government [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 6 |  | 4 |
Gross Unrealized Holding Losses | 2 |  | 3 |
Estimated Fair Value | 257 |  | 232 |
Duke Energy Progress [Member] | Ndtf [Member] | Other Debt Obligations [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 8 |  | 5 |
Duke Energy Progress [Member] | Other Classification [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  | [1] |  | [1]
Gross Unrealized Holding Losses |  | [1] |  | [1]
Estimated Fair Value | 2 | [1] | 2 | [1]
Duke Energy Progress [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 2 |  | 2 |
Duke Energy Florida [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 330 |  | 305 |
Gross Unrealized Holding Losses | 4 |  | 3 |
Estimated Fair Value | 825 |  | 803 |
Duke Energy Florida [Member] | Ndtf [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 327 |  | 304 |
Gross Unrealized Holding Losses | 4 |  | 3 |
Estimated Fair Value | 782 |  | 761 |
Duke Energy Florida [Member] | Ndtf [Member] | Cash and Cash Equivalents [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 7 |  | 20 |
Duke Energy Florida [Member] | Ndtf [Member] | Equity Securities [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 323 |  | 304 |
Gross Unrealized Holding Losses | 4 |  | 1 |
Estimated Fair Value | 574 |  | 546 |
Duke Energy Florida [Member] | Ndtf [Member] | Corporate Debt Securities [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 2 |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 53 |  | 46 |
Duke Energy Florida [Member] | Ndtf [Member] | Municipal Bonds [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 2 |  | 2 |
Duke Energy Florida [Member] | Ndtf [Member] | US Treasury and Government [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 2 |  |  |
Gross Unrealized Holding Losses |  |  | 2 |
Estimated Fair Value | 139 |  | 144 |
Duke Energy Florida [Member] | Ndtf [Member] | Other Debt Obligations [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 7 |  | 3 |
Duke Energy Florida [Member] | Other Classification [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 3 | [1] | 1 | [1]
Gross Unrealized Holding Losses |  | [1] |  | [1]
Estimated Fair Value | 43 | [1] | 42 | [1]
Duke Energy Florida [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value |  |  | 3 |
Duke Energy Florida [Member] | Other Classification [Member] | Municipal Bonds [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 3 |  | 1 |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 43 |  | 39 |
Duke Energy Indiana [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 26 |  | 24 |
Gross Unrealized Holding Losses |  |  | 1 |
Estimated Fair Value | 99 |  | 94 |
Duke Energy Indiana [Member] | Other Classification [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 26 | [1] | 24 | [1]
Gross Unrealized Holding Losses |  | [1] | 1 | [1]
Estimated Fair Value | 99 | [1] | 94 | [1]
Duke Energy Indiana [Member] | Other Classification [Member] | Cash and Cash Equivalents [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 1 |  | 1 |
Duke Energy Indiana [Member] | Other Classification [Member] | Equity Securities [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains | 26 |  | 24 |
Gross Unrealized Holding Losses |  |  |  |
Estimated Fair Value | 68 |  | 65 |
Duke Energy Indiana [Member] | Other Classification [Member] | Municipal Bonds [Member] |  |  |  |
Schedule of Available-for-sale Securities [Line Items] |  |  |  |
Gross Unrealized Holding Gains |  |  |  |
Gross Unrealized Holding Losses |  |  | 1 |
Estimated Fair Value | $ 30 |  | $ 28 |
[1] | These amounts are recorded in Other with Investments and Other Assets on the Condensed Consolidated Balance Sheets.

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- Definition Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 25 -Paragraph 1 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=28360136&loc=d3e22054-111558 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph (aa) -URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27232-111563 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 320 -SubTopic 10 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6871852&loc=d3e26610-111562 + Details
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