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Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 28 Unrealized Loss Position less than 12 months 2 us-gaap_AvailableForSaleSecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue us-gaap true debit instant No definition available. false false false false false false false false false false false terselabel false 1 true true false false -1000000 -1 false false false 2 true true false false -3000000 -3 false false false xbrli:monetaryItemType monetary This item represents the fair value of securities categorized neither as held-to-maturity nor trading securities that have been in a continuous unrealized loss position for less than twelve months. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Emerging Issues Task Force (EITF) -Number 03-1 -Paragraph 21 -Subparagraph a(2) Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS115-1/124-1 -Paragraph 17 -Subparagraph a(1) false 1 The table above includes fair values of $212 million and $298 million at September 30, 2010 and December 31, 2009, respectively, associated with investments held in the NDTF. Additionally, the table above includes fair values of $5 million and $27 million at September 30, 2010 and December 31, 2009, respectively, associated with investments held in the Duke Energy Indiana grantor trust. 2 See Note 8 for information about fair value measurements related to investments in auction rate debt securities. 2 24 false Millions UnKnown UnKnown false true