1.0.0.3 false Unaudited Condensed Consolidated Statements of Operations (USD $) In Millions, except Per Share data false 1 $ false false Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 2 $ false false Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 3 $ false false Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 false 4 $ false false Shares Standard http://www.xbrl.org/2003/instance shares xbrli 0 USD Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 USDEPS Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 5 Net sales: 3 us-gaap_SalesRevenueNetAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false 4 false false 0 0 false false No definition available. false 6 Products 4 us-gaap_SalesRevenueGoodsNet us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 1810000000 1810 false false 2 true true 1752000000 1752 false false 3 true true 5456000000 5456 false false 4 true true 5120000000 5120 false false No definition available. No authoritative reference available. false 7 Services 4 us-gaap_SalesRevenueServicesNet us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 2032000000 2032 false false 2 false true 1910000000 1910 false false 3 false true 5951000000 5951 false false 4 false true 5770000000 5770 false false No definition available. No authoritative reference available. true 8 Total net sales 4 us-gaap_Revenues us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 3842000000 3842 false false 2 false true 3662000000 3662 false false 3 false true 11407000000 11407 false false 4 false true 10890000000 10890 false false No definition available. No authoritative reference available. true 9 Cost of sales: 3 us-gaap_CostOfGoodsAndServicesSoldAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false 4 false false 0 0 false false No definition available. false 10 Products 4 us-gaap_CostOfGoodsSold us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 1586000000 1586 false false 2 false true 1561000000 1561 false false 3 false true 4842000000 4842 false false 4 false true 4588000000 4588 false false No definition available. No authoritative reference available. false 11 Services 4 us-gaap_CostOfServices us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 1838000000 1838 false false 2 false true 1701000000 1701 false false 3 false true 5354000000 5354 false false 4 false true 5159000000 5159 false false No definition available. No authoritative reference available. true 12 Total cost of sales 4 us-gaap_CostOfGoodsAndServicesSold us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 3424000000 3424 false false 2 false true 3262000000 3262 false false 3 false true 10196000000 10196 false false 4 false true 9747000000 9747 false false No definition available. No authoritative reference available. true 13 Litigation Gain 3 us-gaap_GainLossRelatedToLitigationSettlement us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 0 0 false false 2 false true 0 0 false false 3 false true 0 0 false false 4 false true 126000000 126 false false No definition available. No authoritative reference available. true 14 Operating income 3 us-gaap_OperatingIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 418000000 418 false false 2 false true 400000000 400 false false 3 false true 1211000000 1211 false false 4 false true 1269000000 1269 false false No definition available. No authoritative reference available. false 15 Interest and other income, net 3 us-gaap_NonoperatingGainsLosses us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 3000000 3 false false 2 false true 7000000 7 false false 3 false true 12000000 12 false false 4 false true 22000000 22 false false No definition available. No authoritative reference available. false 16 Interest expense 3 us-gaap_InterestExpense us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 68000000 68 false false 2 false true 72000000 72 false false 3 false true 203000000 203 false false 4 false true 214000000 214 false false No definition available. No authoritative reference available. true 17 Income before income taxes 3 lll_IncomeBeforeIncomeTaxes lll false credit duration monetary Income before income taxes. false false false false false false false false false 1 false true 353000000 353 false false 2 false true 335000000 335 false false 3 false true 1020000000 1020 false false 4 false true 1077000000 1077 false false Income before income taxes. No authoritative reference available. false 18 Provision for income taxes 3 us-gaap_IncomeTaxExpenseBenefit us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 100000000 100 false false 2 false true 123000000 123 false false 3 false true 339000000 339 false false 4 false true 395000000 395 false false No definition available. No authoritative reference available. true 19 Net income 3 us-gaap_ProfitLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 253000000 253 false false 2 false true 212000000 212 false false 3 false true 681000000 681 false false 4 false true 682000000 682 false false No definition available. No authoritative reference available. false 20 Less: Net income attributable to noncontrolling interests 3 us-gaap_NetIncomeLossAttributableToNoncontrollingInterest us-gaap true debit duration monetary No definition available. false false false false false false false false false 1 false true 3000000 3 false false 2 false true 2000000 2 false false 3 false true 7000000 7 false false 4 false true 8000000 8 false false No definition available. No authoritative reference available. true 21 Net income attributable to L-3 3 us-gaap_NetIncomeLoss us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 false true 250000000 250 false false 2 false true 210000000 210 false false 3 false true 674000000 674 false false 4 false true 674000000 674 false false No definition available. No authoritative reference available. false 22 Less: Net income allocable to participating securities 3 lll_NetIncomeAllocableToParticipatingSecurities lll false debit duration monetary Net income allocable to participating securities. false false false false false false false false false 1 false true 2000000 2 false false 2 false true 3000000 3 false false 3 false true 6000000 6 false false 4 false true 6000000 6 false false Net income allocable to participating securities. No authoritative reference available. true 23 Net income allocable to L-3 Communications Holdings, Inc.'s common shareholders 3 us-gaap_NetIncomeLossAvailableToCommonStockholdersDiluted us-gaap true credit duration monetary No definition available. false false false false false false false false false 1 true true 248000000 248 false false 2 true true 207000000 207 false false 3 true true 668000000 668 false false 4 true true 668000000 668 false false No definition available. No authoritative reference available. true 24 L-3 Communications Holdings, Inc.'s earnings per common share: 3 us-gaap_EarningsPerShareAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false 4 false false 0 0 false false No definition available. false 25 Basic 4 us-gaap_EarningsPerShareBasic us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 2.13 2.13 false false 2 true true 1.71 1.71 false false 3 true true 5.7 5.7 false false 4 true true 5.48 5.48 false false No definition available. No authoritative reference available. true 26 Diluted 4 us-gaap_EarningsPerShareDiluted us-gaap true na duration decimal No definition available. false false false false false false false false true 1 true true 2.12 2.12 false false 2 true true 1.7 1.7 false false 3 true true 5.68 5.68 false false 4 true true 5.42 5.42 false false No definition available. No authoritative reference available. true 27 L-3 Communications Holdings, Inc.'s weighted average common shares outstanding: 3 us-gaap_WeightedAverageNumberOfSharesOutstandingAbstract us-gaap true na duration string No definition available. false false false false false true false false false 1 false false 0 0 false false 2 false false 0 0 false false 3 false false 0 0 false false 4 false false 0 0 false false No definition available. false 28 Basic 4 us-gaap_WeightedAverageNumberOfSharesOutstandingBasic us-gaap true na duration shares No definition available. false false false false false false false false false 1 false true 116400000 116.4 false false 2 false true 121000000 121.0 false false 3 false true 117100000 117.1 false false 4 false true 121800000 121.8 false false No definition available. No authoritative reference available. true 29 Diluted 4 us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding us-gaap true na duration shares No definition available. false false false false false false false false false 1 false true 117000000 117.0 false false 2 false true 122000000 122.0 false false 3 false true 117600000 117.6 false false 4 false true 123200000 123.2 false false No definition available. No authoritative reference available. true false 4 25 false Millions HundredThousands Hundreds false true