Investments In Available-For-Sale Securities And Other Cost Investments (Details) (USD $) In Millions, unless otherwise specified
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1 Months Ended |
12 Months Ended |
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Apr. 30, 2014
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Dec. 31, 2014
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Dec. 31, 2013
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Schedule of Investments [Line Items] |
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Investments in available-for-sale securities and other cost investments |
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$ 816us-gaap_AvailableForSaleSecuritiesNoncurrent
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$ 1,324us-gaap_AvailableForSaleSecuritiesNoncurrent
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Other Investments [Member] |
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Schedule of Investments [Line Items] |
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Investments in available-for-sale securities and other cost investments |
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47us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_OtherInvestmentsMember
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47us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_OtherInvestmentsMember
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AFS and cost method investments |
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Schedule of Investments [Line Items] |
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Investments in available-for-sale securities and other cost investments |
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71us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = lmca_AfsAndCostMethodInvestmentsMember
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71us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = lmca_AfsAndCostMethodInvestmentsMember
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Barnes & Noble, Inc. |
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Schedule of Investments [Line Items] |
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Sale of stock, ownership percentage of cost investment after transaction |
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2.00%lmca_Saleofstockownershippercentageofcostinvestmentaftertransaction / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_BarnesNobleIncMember
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Percentage of shares sold |
90.00%lmca_Percentageofsharessold / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_BarnesNobleIncMember
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Proceeds from Sale of Available-for-sale Securities |
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247us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_BarnesNobleIncMember
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Live Nation | Debt Securities |
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Schedule of Investments [Line Items] |
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Investments in available-for-sale securities and other cost investments |
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24us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_DebtSecuritiesMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_LiveNationMember
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24us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_DebtSecuritiesMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_LiveNationMember
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Fair Value Option Securities |
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Schedule of Investments [Line Items] |
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Investments in available-for-sale securities and other cost investments |
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745us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_EligibleItemOrGroupForFairValueOptionAxis = lmca_FairValueOptionSecuritiesMember
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1,253us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_EligibleItemOrGroupForFairValueOptionAxis = lmca_FairValueOptionSecuritiesMember
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Fair Value Option Securities | Time Warner Inc |
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Schedule of Investments [Line Items] |
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Investments in available-for-sale securities and other cost investments |
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363us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_EligibleItemOrGroupForFairValueOptionAxis = lmca_FairValueOptionSecuritiesMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_TimeWarnerIncMember
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297us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_EligibleItemOrGroupForFairValueOptionAxis = lmca_FairValueOptionSecuritiesMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_TimeWarnerIncMember
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Fair Value Option Securities | Time Warner Cable Inc |
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Schedule of Investments [Line Items] |
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Investments in available-for-sale securities and other cost investments |
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320us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_EligibleItemOrGroupForFairValueOptionAxis = lmca_FairValueOptionSecuritiesMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_TimeWarnerCableIncMember
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Fair Value Option Securities | Viacom, Inc. |
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Schedule of Investments [Line Items] |
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Investments in available-for-sale securities and other cost investments |
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273us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_EligibleItemOrGroupForFairValueOptionAxis = lmca_FairValueOptionSecuritiesMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_ViacomIncMember
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317us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_EligibleItemOrGroupForFairValueOptionAxis = lmca_FairValueOptionSecuritiesMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_ViacomIncMember
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Fair Value Option Securities | Barnes & Noble, Inc. |
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Schedule of Investments [Line Items] |
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Investments in available-for-sale securities and other cost investments |
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27us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_EligibleItemOrGroupForFairValueOptionAxis = lmca_FairValueOptionSecuritiesMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_BarnesNobleIncMember
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255us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_EligibleItemOrGroupForFairValueOptionAxis = lmca_FairValueOptionSecuritiesMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_BarnesNobleIncMember
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Fair Value Option Securities | Other AFS Equity Securities | Equity Securities |
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Schedule of Investments [Line Items] |
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Investments in available-for-sale securities and other cost investments |
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55us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_EligibleItemOrGroupForFairValueOptionAxis = lmca_FairValueOptionSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_EquitySecuritiesMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_OtherAfsEquitySecuritiesMember
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37us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_EligibleItemOrGroupForFairValueOptionAxis = lmca_FairValueOptionSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_EquitySecuritiesMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_OtherAfsEquitySecuritiesMember
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Fair Value Option Securities | Other AFS Debt Securities | Debt Securities |
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Schedule of Investments [Line Items] |
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Investments in available-for-sale securities and other cost investments |
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$ 27us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_EligibleItemOrGroupForFairValueOptionAxis = lmca_FairValueOptionSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_DebtSecuritiesMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_OtherAfsDebtSecuritiesMember
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$ 27us-gaap_AvailableForSaleSecuritiesNoncurrent / us-gaap_EligibleItemOrGroupForFairValueOptionAxis = lmca_FairValueOptionSecuritiesMember / us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis = us-gaap_DebtSecuritiesMember / us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis = lmca_OtherAfsDebtSecuritiesMember
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