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Annual report pursuant to Section 13 and 15(d)

Sirius XM Transactions (Details)

v2.4.1.9
Sirius XM Transactions (Details) (USD $)
 1 Months Ended 3 Months Ended 12 Months Ended 1 Months Ended 0 Months Ended 15 Months Ended 1 Months Ended
Oct. 31, 2013
Mar. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jan. 18, 2013
Nov. 04, 2013
Apr. 25, 2014
Nov. 14, 2013
Dec. 31, 2014
tranche
Aug. 31, 2014
May 31, 2014
Oct. 31, 2014
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Ìý Ìý Ìý $ (10,372,000,000)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Preferred Stock, Par or Stated Value Per Share Ìý Ìý $ 0.01us-gaap_PreferredStockParOrStatedValuePerShare $ 0.01us-gaap_PreferredStockParOrStatedValuePerShare Ìý Ìý Ìý Ìý Ìý $ 0.01us-gaap_PreferredStockParOrStatedValuePerShare Ìý Ìý Ìý
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain Ìý 7,500,000,000us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeRemeasurementGain Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Goodwill Ìý Ìý 14,345,000,000us-gaap_Goodwill 14,365,000,000us-gaap_Goodwill 200,000,000us-gaap_Goodwill Ìý Ìý Ìý Ìý 14,345,000,000us-gaap_Goodwill Ìý Ìý Ìý
Goodwill, Acquired During Period Ìý Ìý Ìý 14,165,000,000us-gaap_GoodwillAcquiredDuringPeriod Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Stock Repurchased and Retired During Period, Shares Ìý Ìý 0us-gaap_StockRepurchasedAndRetiredDuringPeriodShares Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Payments for Repurchase of Common Stock Ìý Ìý Ìý 140,000,000us-gaap_PaymentsForRepurchaseOfCommonStock 323,000,000us-gaap_PaymentsForRepurchaseOfCommonStock Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Shares retired 6,300,000us-gaap_TreasuryStockSharesRetired Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
SIRIUS XM Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Net Ìý Ìý Ìý Ìý Ìý 10,372,000,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredGoodwillAndLiabilitiesAssumedNet
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Noncurrent Assets Ìý Ìý Ìý Ìý Ìý 253,000,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedOtherNoncurrentAssets
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Combination, Step Acquisition, Equity Interest in Acquiree, Remeasurement Gain Ìý 7,500,000,000us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeRemeasurementGain
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Combination, Step Acquisition, Equity Interest in Acquiree, Fair Value Ìý 10,215,000,000us-gaap_BusinessCombinationStepAcquisitionEquityInterestInAcquireeFairValue1
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Initial noncontrolling interest Ìý 10,286,000,000lmca_BusinessCombinationStepAcquisitionInitialNoncontrollingInterest
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value Ìý Ìý Ìý Ìý Ìý 10,841,000,000us-gaap_BusinessCombinationAcquisitionOfLessThan100PercentNoncontrollingInterestFairValue
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net Ìý Ìý Ìý Ìý Ìý 21,466,000,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNet
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition, Purchase Price Allocation, Current Assets, Cash and Cash Equivalents Ìý Ìý Ìý Ìý Ìý 569,000,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCashAndEquivalents
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition, Purchase Price Allocation, Current Assets, Receivables Ìý Ìý Ìý Ìý Ìý 210,000,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsReceivables
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition, Purchase Price Allocation, Property, Plant and Equipment Ìý Ìý Ìý Ìý Ìý 1,714,000,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedPropertyPlantAndEquipment
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Goodwill Ìý Ìý Ìý Ìý Ìý 13,775,000,000us-gaap_Goodwill
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangibles Ìý Ìý Ìý Ìý Ìý 930,000,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition, Purchase Price Allocation, Current Assets, Prepaid Expense and Other Assets Ìý Ìý Ìý Ìý Ìý 480,000,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentAssetsPrepaidExpenseAndOtherAssets
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition, Purchase Price Allocation, Noncurrent Liabilities, Long-term Debt Ìý Ìý Ìý Ìý Ìý (2,490,000,000)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesLongTermDebt
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition, Purchase Price Allocation, Current Liabilities, Deferred Revenue Ìý Ìý Ìý Ìý Ìý (1,565,000,000)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedCurrentLiabilitiesDeferredRevenue
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition, Purchase Price Allocation, Deferred Taxes Asset (Liability), Net, Noncurrent Ìý Ìý Ìý Ìý Ìý (685,000,000)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedDeferredTaxLiabilitiesNoncurrent
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition, Purchase Price Allocation, Other Liabilities Ìý Ìý Ìý Ìý Ìý (1,002,000,000)us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedNoncurrentLiabilitiesOther
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
SIRIUS XM | Maximum Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Noncontrolling Interest, Ownership Percentage by Noncontrolling Owners Ìý 50.00%us-gaap_MinorityInterestOwnershipPercentageByNoncontrollingOwners
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember
/ us-gaap_RangeAxis
= us-gaap_MaximumMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
SIRIUS XM | Pro Forma [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Revenue Ìý Ìý Ìý Ìý 3,730,000,000us-gaap_BusinessAcquisitionsProFormaRevenue
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember
/ us-gaap_StatementScenarioAxis
= us-gaap_ProFormaMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Operating income (loss) Ìý Ìý Ìý Ìý 686,000,000lmca_BusinessAcquisitionProFormaOperatingIncomeLoss
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember
/ us-gaap_StatementScenarioAxis
= us-gaap_ProFormaMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Interest expense Ìý Ìý Ìý Ìý (162,000,000)lmca_BusinessAcquisitionProFormaInterestExpense
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember
/ us-gaap_StatementScenarioAxis
= us-gaap_ProFormaMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Share of earnings (loss) of affiliates Ìý Ìý Ìý Ìý (21,000,000)lmca_BusinessAcquisitionProFormaShareOfEarningsLossOfAffiliates
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember
/ us-gaap_StatementScenarioAxis
= us-gaap_ProFormaMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Less earnings (loss) attributable to the noncontrolling interest Ìý Ìý Ìý Ìý 1,736,000,000lmca_BusinessAcquisitionProFormaNetEarningsLossAttributableToNoncontrollingInterest
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember
/ us-gaap_StatementScenarioAxis
= us-gaap_ProFormaMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Net Earnings (loss) from continuing operatins attributable to Liberty stockholders Ìý Ìý Ìý Ìý 2,052,000,000us-gaap_BusinessAcquisitionsProFormaNetIncomeLoss
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember
/ us-gaap_StatementScenarioAxis
= us-gaap_ProFormaMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Pro Forma basic net earnings (loss) from continuing operations attributable to Liberty stockholders per common share (note 2) Ìý Ìý Ìý Ìý $ 5.68us-gaap_BusinessAcquisitionProFormaEarningsPerShareBasic
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember
/ us-gaap_StatementScenarioAxis
= us-gaap_ProFormaMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Pro Forma diluted net earnings (loss) from continuing operations attributable to Liberty stockholders per common share (note 2) Ìý Ìý Ìý Ìý $ 5.52us-gaap_BusinessAcquisitionProFormaEarningsPerShareDiluted
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember
/ us-gaap_StatementScenarioAxis
= us-gaap_ProFormaMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
SIRIUS XM Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Purchase of shares in equity method investee Ìý 50,000,000lmca_PurchaseOfSharesInEquityMethodInvestee
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý 50,000,000lmca_PurchaseOfSharesInEquityMethodInvestee
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Preferred Stock, Par or Stated Value Per Share Ìý $ 0.001us-gaap_PreferredStockParOrStatedValuePerShare
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Convertible Preferred Stock, Shares Issued upon Conversion Ìý 1,293,509,076us-gaap_ConvertiblePreferredStockSharesIssuedUponConversion
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Ownership percentage Ìý Ìý 56.00%us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
SIRIUS XM | Minimum Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Ownership percentage Ìý 50.00%us-gaap_SubsidiaryOrEquityMethodInvesteeCumulativePercentageOwnershipAfterAllTransactions
/ us-gaap_RangeAxis
= us-gaap_MinimumMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
FCC licences [Member] | SIRIUS XM Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition, Purchase Price Allocation, Intangible Assets Not Amortizable Ìý Ìý Ìý Ìý Ìý 8,600,000,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember
/ us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis
= lmca_FccLicencesMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Trade Names [Member] | SIRIUS XM Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition, Purchase Price Allocation, Intangible Assets Not Amortizable Ìý Ìý Ìý Ìý Ìý 930,000,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIndefiniteLivedIntangibleAssets
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember
/ us-gaap_IndefiniteLivedIntangibleAssetsByMajorClassAxis
= us-gaap_TradeNamesMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Deferred tax liability [Member] | SIRIUS XM Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Goodwill, Allocation Adjustment Ìý Ìý Ìý 227,000,000us-gaap_GoodwillPurchaseAccountingAdjustments
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember
/ us-gaap_NonrecurringAdjustmentAxis
= lmca_DeferredtaxliabilityMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Contract fair value [Member] | SIRIUS XM Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Goodwill, Allocation Adjustment Ìý Ìý Ìý 18,000,000us-gaap_GoodwillPurchaseAccountingAdjustments
/ us-gaap_BusinessAcquisitionAxis
= lmca_SiriusXmMember
/ us-gaap_NonrecurringAdjustmentAxis
= lmca_ContractfairvalueMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
SIRIUS XM | Agero [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition, Cost of Acquired Entity, Purchase Price Ìý Ìý Ìý 525,000,000us-gaap_BusinessCombinationConsiderationTransferredIncludingEquityInterestInAcquireeHeldPriorToCombination1
/ us-gaap_BusinessAcquisitionAxis
= lmca_AgeroMember
/ dei_LegalEntityAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Goodwill, Acquired During Period Ìý Ìý Ìý Ìý Ìý Ìý 390,000,000us-gaap_GoodwillAcquiredDuringPeriod
/ us-gaap_BusinessAcquisitionAxis
= lmca_AgeroMember
/ dei_LegalEntityAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý
SIRIUS XM | Sirius XM Liberty Repurchase Agreement [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Stock Repurchased and Retired During Period, Shares Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý 43,712,265us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_SiriusxmLibertyRepurchaseAgreementMember 		136,600,826us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_SiriusxmLibertyRepurchaseAgreementMember 		Ìý Ìý Ìý
Payments for Repurchase of Common Stock Ìý Ìý Ìý Ìý Ìý Ìý Ìý 340,000,000us-gaap_PaymentsForRepurchaseOfCommonStock
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_SiriusxmLibertyRepurchaseAgreementMember 		Ìý 500,000,000us-gaap_PaymentsForRepurchaseOfCommonStock
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_SiriusxmLibertyRepurchaseAgreementMember 		Ìý Ìý Ìý
Number of tranches for stock repurchase Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý 3lmca_NumberOfTranchesOfStockRepurchase
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_SiriusxmLibertyRepurchaseAgreementMember 		Ìý Ìý Ìý
Treasury Stock Acquired, Average Cost Per Share Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý $ 3.6603us-gaap_TreasuryStockAcquiredAverageCostPerShare
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_SiriusxmLibertyRepurchaseAgreementMember 		Ìý Ìý Ìý
Share repurchases, discount from market price Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý 1.50%lmca_Sharerepurchasesdiscountfrommarketprice
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_SiriusxmLibertyRepurchaseAgreementMember 		Ìý Ìý Ìý
Shares Repurchased Discount From Market Measurement Period Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý 10 days Ìý Ìý Ìý
Volume weighted average share price, cap Ìý Ìý $ 4.18lmca_Volumeweightedaveragesharepricecap
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_SiriusxmLibertyRepurchaseAgreementMember 		Ìý Ìý Ìý Ìý Ìý Ìý $ 4.18lmca_Volumeweightedaveragesharepricecap
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_SiriusxmLibertyRepurchaseAgreementMember 		Ìý Ìý Ìý
Volume weighted average share price, floor Ìý Ìý $ 3.64lmca_Volumeweightedaveragesharepricefloor
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_SiriusxmLibertyRepurchaseAgreementMember 		Ìý Ìý Ìý Ìý Ìý Ìý $ 3.64lmca_Volumeweightedaveragesharepricefloor
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_SiriusxmLibertyRepurchaseAgreementMember 		Ìý Ìý Ìý
Stock repurchased as a percentage of shares outstanding Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý 2.00%lmca_Stockrepurchasedasapercentageofsharesoutstanding
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_SiriusxmLibertyRepurchaseAgreementMember 		Ìý Ìý Ìý
SIRIUS XM | May Accelerated Share Repurchase Agreement [member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Stock Repurchased and Retired During Period, Shares Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý 39,346,125us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_MayAcceleratedShareRepurchaseAgreementMember 		112,500,000us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_MayAcceleratedShareRepurchaseAgreementMember 		Ìý
Payments for Repurchase of Common Stock Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý 600,000,000us-gaap_PaymentsForRepurchaseOfCommonStock
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_MayAcceleratedShareRepurchaseAgreementMember 		Ìý
Stock Repurchase Program, Authorized Amount Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý 600,000,000us-gaap_StockRepurchaseProgramAuthorizedAmount1
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_MayAcceleratedShareRepurchaseAgreementMember 		Ìý
Share Repurchase Payment Adjustment Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý 94,000,000lmca_ShareRepurchasePaymentAdjustment
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_MayAcceleratedShareRepurchaseAgreementMember 		Ìý Ìý
SIRIUS XM | August Accelerated Share Repurchase Agreement [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Stock Repurchased and Retired During Period, Shares Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý 51,884,795us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_AugustAcceleratedShareRepurchaseAgreementMember 		Ìý 19,431,708us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_AugustAcceleratedShareRepurchaseAgreementMember
Payments for Repurchase of Common Stock Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý 250,000,000us-gaap_PaymentsForRepurchaseOfCommonStock
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_AugustAcceleratedShareRepurchaseAgreementMember 		Ìý Ìý
Stock Repurchase Program, Authorized Amount Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý 250,000,000us-gaap_StockRepurchaseProgramAuthorizedAmount1
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_ShareRepurchaseProgramAxis
= lmca_AugustAcceleratedShareRepurchaseAgreementMember 		Ìý Ìý
OEM Relationship and Computer Software [Member] | SIRIUS XM | Agero [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangibles Ìý Ìý Ìý $ 247,000,000us-gaap_BusinessCombinationRecognizedIdentifiableAssetsAcquiredAndLiabilitiesAssumedIntangibles
/ us-gaap_BusinessAcquisitionAxis
= lmca_AgeroMember
/ us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis
= lmca_OemRelationshipAndComputerSoftwareMember
/ dei_LegalEntityAxis
= lmca_SiriusXmMember 		Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
OEM relationship [Member] | SIRIUS XM | Agero [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Ìý Ìý Ìý Ìý Ìý Ìý 15 years Ìý Ìý Ìý Ìý Ìý Ìý
Computer Software, Intangible Asset [Member] | SIRIUS XM | Agero [Member] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Business Acquisition [Line Items] Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý Ìý
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life Ìý Ìý Ìý Ìý Ìý Ìý 10 years Ìý Ìý Ìý Ìý Ìý Ìý