1.0.0.3 false 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 1884000000 1884 false false 2 true true 1765000000 1765 false false 3 true true 3646000000 3646 false false 4 true true 3368000000 3368 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 2045000000 2045 false false 2 false true 1957000000 1957 false false 3 false true 3919000000 3919 false false 4 false true 3860000000 3860 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 3929000000 3929 false false 2 false true 3722000000 3722 false false 3 false true 7565000000 7565 false false 4 false true 7228000000 7228 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 1690000000 1690 false false 2 false true 1598000000 1598 false false 3 false true 3256000000 3256 false false 4 false true 3027000000 3027 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 1822000000 1822 false false 2 false true 1749000000 1749 false false 3 false true 3516000000 3516 false false 4 false true 3458000000 3458 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 3512000000 3512 false false 2 false true 3347000000 3347 false false 3 false true 6772000000 6772 false false 4 false true 6485000000 6485 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 126000000 126 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 417000000 417 false false 2 false true 501000000 501 false false 3 false true 793000000 793 false false 4 false true 869000000 869 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 6000000 6 false false 2 false true 7000000 7 false false 3 false true 9000000 9 false false 4 false true 15000000 15 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 69000000 69 false false 2 false true 66000000 66 false false 3 false true 135000000 135 false false 4 false true 142000000 142 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 354000000 354 false false 2 false true 442000000 442 false false 3 false true 667000000 667 false false 4 false true 742000000 742 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 127000000 127 false false 2 false true 164000000 164 false false 3 false true 239000000 239 false false 4 false true 272000000 272 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 227000000 227 false false 2 false true 278000000 278 false false 3 false true 428000000 428 false false 4 false true 470000000 470 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 2000000 2 false false 2 false true 3000000 3 false false 3 false true 4000000 4 false false 4 false true 6000000 6 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 225000000 225 false false 2 false true 275000000 275 false false 3 false true 424000000 424 false false 4 false true 464000000 464 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 2000000 2 false false 3 false true 4000000 4 false false 4 false true 3000000 3 false false Net income allocable to participating securities. No authoritative reference available. true 23 Net income allocable to L-3 Holdings' 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 223000000 223 false false 2 true true 273000000 273 false false 3 true true 420000000 420 false false 4 true true 461000000 461 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 1.91 1.91 false false 2 true true 2.24 2.24 false false 3 true true 3.58 3.58 false false 4 true true 3.77 3.77 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 1.9 1.9 false false 2 true true 2.21 2.21 false false 3 true true 3.56 3.56 false false 4 true true 3.72 3.72 false false No definition available. No authoritative reference available. true 27 L-3 Communications Holdings, Inc.'s weighted average common shares outstanding: 3 lll_WeightedAverageCommonSharesOutstandingAbstract lll false na duration string Weighted average common shares outstanding. 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 Weighted average common shares outstanding. 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 116500000 116.5 false false 2 false true 122000000 122.0 false false 3 false true 117400000 117.4 false false 4 false true 122300000 122.3 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 117200000 117.2 false false 2 false true 123500000 123.5 false false 3 false true 118000000 118.0 false false 4 false true 123800000 123.8 false false No definition available. No authoritative reference available. true false 4 25 false Millions HundredThousands Hundreds false true