| 
           Investments In Affiliates Accounted For Using The Equity Method (Details 1) (USD $) Share data in Millions, except Per Share data, unless otherwise specified 
         | 
        12 Months Ended | 
        1 Months Ended | 
        3 Months Ended | 
        12 Months Ended | 
        1 Months Ended | 
         | 
      
      
        | 
           Dec. 31, 2014 
         | 
        
           Dec. 31, 2013 
         | 
        
           Dec. 31, 2012 
         | 
        
           Jan. 18, 2013 
         | 
        
           Mar. 31, 2013 
         | 
        
           Dec. 31, 2015 
         | 
        
           May 31, 2013 
         | 
        
           May 01, 2013 
         | 
      
      
        | Schedule of Equity Method Investments [Line Items] | 
         
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        | Income Tax Expense (Benefit) | 
        
$ 66,000,000us-gaap_IncomeTaxExpenseBenefit
 | 
        
$ (135,000,000)us-gaap_IncomeTaxExpenseBenefit
 | 
        
$ 469,000,000us-gaap_IncomeTaxExpenseBenefit
 | 
         
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        | Proceeds from Equity Method Investment, Dividends or Distributions | 
         
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 | 
        
165,000,000us-gaap_EquityMethodInvestmentDividendsOrDistributions
 | 
         
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        | Live Nation | 
         
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        | Schedule of Equity Method Investments [Line Items] | 
         
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        | Purchase of shares in equity method investee | 
        
1.7lmca_PurchaseOfSharesInEquityMethodInvestee / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_LiveNationMember
 | 
        
1.7lmca_PurchaseOfSharesInEquityMethodInvestee / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_LiveNationMember
 | 
        
11.0lmca_PurchaseOfSharesInEquityMethodInvestee / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_LiveNationMember
 | 
         
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        | Payments to Acquire Equity Method Investments | 
        
39,000,000us-gaap_PaymentsToAcquireEquityMethodInvestments / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_LiveNationMember
 | 
        
19,000,000us-gaap_PaymentsToAcquireEquityMethodInvestments / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_LiveNationMember
 | 
        
107,000,000us-gaap_PaymentsToAcquireEquityMethodInvestments / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_LiveNationMember
 | 
         
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        | Equity Method Investment, Quoted Market Value | 
        
1,403,000,000us-gaap_EquityMethodInvestmentQuotedMarketValue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_LiveNationMember
 | 
         
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        | Equity Method Investment, Ownership Percentage | 
        
27.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_LiveNationMember
 | 
         
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        | shares underlying borrowed share position, unwound | 
         
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8.1lmca_SharesUnderlyingBorrowedSharePositionUnwound / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_LiveNationMember
 | 
         
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        | SIRIUS XM | 
         
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        | Schedule of Equity Method Investments [Line Items] | 
         
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        | Purchase of shares in equity method investee | 
         
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50.0lmca_PurchaseOfSharesInEquityMethodInvestee / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_SiriusXmMember
 | 
        
50.0lmca_PurchaseOfSharesInEquityMethodInvestee / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_SiriusXmMember
 | 
         
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        | shares underlying borrowed share position, unwound | 
         
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720.0lmca_SharesUnderlyingBorrowedSharePositionUnwound / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_SiriusXmMember
 | 
         
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        | SIRIUS XM | Sirius XM Canada | 
         
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        | Schedule of Equity Method Investments [Line Items] | 
         
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        | Contract Term | 
         
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 | 
        10 years
 | 
         
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        | Sirius XM Canada | 
         
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        | Schedule of Equity Method Investments [Line Items] | 
         
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        | Equity Method Investment, Quoted Market Value | 
        
247,000,000us-gaap_EquityMethodInvestmentQuotedMarketValue / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_SiriusXmCanadaMember
 | 
         
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        | Equity Method Investment, Ownership Percentage | 
        
37.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_SiriusXmCanadaMember
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        | Charter Communications | 
         
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        | Schedule of Equity Method Investments [Line Items] | 
         
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        | Equity Method Investment, Aggregate Cost | 
         
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2,600,000,000us-gaap_EquityMethodInvestmentAggregateCost / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_CharterCommunicationsMember
 | 
      
      
        | excess amortization in share of earnings (loss) | 
        
60,000,000lmca_ExcessAmortizationInShareOfEarningsLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_CharterCommunicationsMember
 | 
        
51,000,000lmca_ExcessAmortizationInShareOfEarningsLoss / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_CharterCommunicationsMember
 | 
         
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        | Purchase of shares in equity method investee | 
         
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26.9lmca_PurchaseOfSharesInEquityMethodInvestee / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_CharterCommunicationsMember
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        | Warrants acquired | 
         
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1.1lmca_WarrantsAcquired / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_CharterCommunicationsMember
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        | Equity Method Investment, Ownership Percentage | 
         
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27.00%us-gaap_EquityMethodInvestmentOwnershipPercentage / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_CharterCommunicationsMember
 | 
      
      
        | Price-per-share | 
         
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$ 95.50us-gaap_SaleOfStockPricePerShare / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_CharterCommunicationsMember
 | 
      
      
        | Equity method investment, cash paid for acquisition | 
         
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1,200,000,000lmca_EquityMethodInvestmentCashPaidForAcquisition / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_CharterCommunicationsMember
 | 
      
      
        | shares underlying borrowed share position, unwound | 
         
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20.3lmca_SharesUnderlyingBorrowedSharePositionUnwound / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_CharterCommunicationsMember
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        | Difference between carrying amount and underlying equity | 
         
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2,500,000,000us-gaap_EquityMethodInvestmentDifferenceBetweenCarryingAmountAndUnderlyingEquity / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_CharterCommunicationsMember
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        | Loss recognized on equity method investments | 
        
72,000,000lmca_EquityMethodInvestmentLossOnInvestmentDueToWarrantAndStockOptionExercisesBelowBookBasis / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_CharterCommunicationsMember
 | 
        
93,000,000lmca_EquityMethodInvestmentLossOnInvestmentDueToWarrantAndStockOptionExercisesBelowBookBasis / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_CharterCommunicationsMember
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        | SIRIUS XM | Sirius XM Canada | 
         
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        | Schedule of Equity Method Investments [Line Items] | 
         
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        | SIRIUS XM total assets | 
        
7,000,000us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets / dei_LegalEntityAxis = lmca_SiriusXmMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = lmca_SiriusXmCanadaMember
 | 
        
10,000,000us-gaap_EquityMethodInvestmentSummarizedFinancialInformationAssets / dei_LegalEntityAxis = lmca_SiriusXmMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = lmca_SiriusXmCanadaMember
 | 
         
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        | SIRIUS XM total liabilities | 
        
18,000,000us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities / dei_LegalEntityAxis = lmca_SiriusXmMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = lmca_SiriusXmCanadaMember
 | 
        
21,000,000us-gaap_EquityMethodInvestmentSummarizedFinancialInformationLiabilities / dei_LegalEntityAxis = lmca_SiriusXmMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = lmca_SiriusXmCanadaMember
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        | Revenue from Related Parties | 
        
50,000,000us-gaap_RevenueFromRelatedParties / dei_LegalEntityAxis = lmca_SiriusXmMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = lmca_SiriusXmCanadaMember
 | 
        
49,000,000us-gaap_RevenueFromRelatedParties / dei_LegalEntityAxis = lmca_SiriusXmMember / us-gaap_RelatedPartyTransactionsByRelatedPartyAxis = lmca_SiriusXmCanadaMember
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        | SIRIUS XM | SIRIUS XM | 
         
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        | Schedule of Equity Method Investments [Line Items] | 
         
 | 
         
 | 
         
 | 
         
 | 
         
 | 
         
 | 
         
 | 
         
 | 
      
      
        | Income Tax Expense (Benefit) | 
         
 | 
         
 | 
        
3,000,000,000us-gaap_IncomeTaxExpenseBenefit / dei_LegalEntityAxis = lmca_SiriusXmMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_SiriusXmMember
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        | Broadcast rights | 
        
70,000,000lmca_BroadcastRights / dei_LegalEntityAxis = lmca_SiriusXmMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_SiriusXmMember
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        | SIRIUS XM | Sirius XM Canada | 
         
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        | Schedule of Equity Method Investments [Line Items] | 
         
 | 
         
 | 
         
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        | Proceeds from Equity Method Investment, Dividends or Distributions | 
        
43,000,000us-gaap_EquityMethodInvestmentDividendsOrDistributions / dei_LegalEntityAxis = lmca_SiriusXmMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_SiriusXmCanadaMember
 | 
        
17,000,000us-gaap_EquityMethodInvestmentDividendsOrDistributions / dei_LegalEntityAxis = lmca_SiriusXmMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_SiriusXmCanadaMember
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        | Deferred revenue | SIRIUS XM | 
         
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        | Schedule of Equity Method Investments [Line Items] | 
         
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        | Investments, at fair value | 
         
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 21,000,000us-gaap_FairValueLiabilitiesMeasuredOnRecurringBasisObligations / us-gaap_BalanceSheetLocationAxis = lmca_DeferredRevenueMember / dei_LegalEntityAxis = lmca_SiriusXmMember
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