Annual report pursuant to Section 13 and 15(d)

Summary of Significant Accounting Policies (Details)

v2.4.1.9
Summary of Significant Accounting Policies (Details) (USD $)
In Millions, unless otherwise specified
 12 Months Ended
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Allowance for Doubtful Accounts Receivable, Current $ 8us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent $ 4us-gaap_AllowanceForDoubtfulAccountsReceivableCurrent  
Provision for Doubtful Accounts 45us-gaap_ProvisionForDoubtfulAccounts 4us-gaap_ProvisionForDoubtfulAccounts  
Allowance for Doubtful Accounts Receivable, Write-offs 41us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs 1us-gaap_AllowanceForDoubtfulAccountsReceivableWriteOffs  
Total Value Of Non Strategic Securities 745lmca_TotalValueOfFairValueOptionSecurities 1,253lmca_TotalValueOfFairValueOptionSecurities  
Property, Plant and Equipment, Gross 2,257us-gaap_PropertyPlantAndEquipmentGross 2,149us-gaap_PropertyPlantAndEquipmentGross  
Depreciation 209us-gaap_Depreciation 200us-gaap_Depreciation 23us-gaap_Depreciation
Advertising Expense 226us-gaap_AdvertisingExpense 181us-gaap_AdvertisingExpense 4us-gaap_AdvertisingExpense
Weighted Average Number of Shares Outstanding, Basic 342us-gaap_WeightedAverageNumberOfSharesOutstandingBasic 355us-gaap_WeightedAverageNumberOfSharesOutstandingBasic 361us-gaap_WeightedAverageNumberOfSharesOutstandingBasic
Weighted Average Number Diluted Shares Outstanding Adjustment 3us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment 4us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment 11us-gaap_WeightedAverageNumberDilutedSharesOutstandingAdjustment
Share-based Compensation 217us-gaap_ShareBasedCompensation 193us-gaap_ShareBasedCompensation 46us-gaap_ShareBasedCompensation
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized 58us-gaap_EmployeeServiceShareBasedCompensationNonvestedAwardsTotalCompensationCostNotYetRecognized    
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition 2 years 3 months 18 days    
Weighted Average Number of Shares Outstanding, Diluted 345us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding 359us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding 372us-gaap_WeightedAverageNumberOfDilutedSharesOutstanding
Land [Member]      
Property, Plant and Equipment, Gross 124us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LandMember 		59us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_LandMember 		 
Building and Improvements [Member]      
Property, Plant and Equipment, Gross 162us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BuildingAndBuildingImprovementsMember 		157us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_BuildingAndBuildingImprovementsMember 		 
Equipment [Member]      
Property, Plant and Equipment, Gross 230us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_EquipmentMember 		257us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_EquipmentMember 		 
Satellite system [Member]      
Property, Plant and Equipment, Gross 1,590us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= lmca_SatellitesystemMember 		1,573us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= lmca_SatellitesystemMember 		 
Construction in Progress [Member]      
Property, Plant and Equipment, Gross 151us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ConstructionInProgressMember 		103us-gaap_PropertyPlantAndEquipmentGross
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= us-gaap_ConstructionInProgressMember 		 
SIRIUS XM      
Share-based Compensation 148us-gaap_ShareBasedCompensation
/ dei_LegalEntityAxis
= lmca_SiriusXmMember 		133us-gaap_ShareBasedCompensation
/ dei_LegalEntityAxis
= lmca_SiriusXmMember 		 
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition 2 years 4 months 24 days    
SIRIUS XM | Satellite system [Member]      
Property, Plant and Equipment, Gross   87us-gaap_PropertyPlantAndEquipmentGross
/ dei_LegalEntityAxis
= lmca_SiriusXmMember
/ us-gaap_PropertyPlantAndEquipmentByTypeAxis
= lmca_SatellitesystemMember 		 
Minimum | Building and Improvements [Member]      
Property, Plant and Equipment, Useful Life 10 years    
Minimum | Equipment [Member]      
Property, Plant and Equipment, Useful Life 3 years    
Minimum | Satellite system [Member]      
Property, Plant and Equipment, Useful Life 2 years    
Maximum | Building and Improvements [Member]      
Property, Plant and Equipment, Useful Life 40 years    
Maximum | Equipment [Member]      
Property, Plant and Equipment, Useful Life 20 years    
Maximum | Satellite system [Member]      
Property, Plant and Equipment, Useful Life 15 years    
Programming and content expense      
Allocated Share-based Compensation Expense 17us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_InformationByFinancialStatementLineItemAxis
= lmca_ProgrammingAndContentExpenseMember 		15us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_InformationByFinancialStatementLineItemAxis
= lmca_ProgrammingAndContentExpenseMember 		 
Customer service and billing      
Allocated Share-based Compensation Expense 5us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_InformationByFinancialStatementLineItemAxis
= lmca_CustomerServiceAndBillingMember 		4us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_InformationByFinancialStatementLineItemAxis
= lmca_CustomerServiceAndBillingMember 		 
Other cost of subscriber services      
Allocated Share-based Compensation Expense 8us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_InformationByFinancialStatementLineItemAxis
= lmca_OthercostofsubscriberservicesMember 		7us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_InformationByFinancialStatementLineItemAxis
= lmca_OthercostofsubscriberservicesMember 		 
Other Operating Income Expense [Member]      
Allocated Share-based Compensation Expense 17us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_InformationByFinancialStatementLineItemAxis
= us-gaap_OtherOperatingIncomeExpenseMember 		14us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_InformationByFinancialStatementLineItemAxis
= us-gaap_OtherOperatingIncomeExpenseMember 		 
Selling, General and Administrative Expenses      
Allocated Share-based Compensation Expense $ 170us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_InformationByFinancialStatementLineItemAxis
= us-gaap_SellingGeneralAndAdministrativeExpensesMember 		$ 153us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_InformationByFinancialStatementLineItemAxis
= us-gaap_SellingGeneralAndAdministrativeExpensesMember 		$ 46us-gaap_AllocatedShareBasedCompensationExpense
/ us-gaap_InformationByFinancialStatementLineItemAxis
= us-gaap_SellingGeneralAndAdministrativeExpensesMember