Quarterly report pursuant to Section 13 or 15(d)

Investments In Available-For-Sale Securities And Other Cost Investments (Details)

v2.4.1.9
Investments In Available-For-Sale Securities And Other Cost Investments (Details) (USD $)
In Millions, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Schedule of Investments [Line Items]    
Investments in available-for-sale securities and other cost investments $ 671us-gaap_AvailableForSaleSecuritiesNoncurrent $ 816us-gaap_AvailableForSaleSecuritiesNoncurrent
Proceeds from Sale of Available-for-sale Securities 113us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities  
Accumulated Other Comprehensive Income (Loss), Available-for-sale Securities Adjustment, Net of Tax 0us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax 0us-gaap_AccumulatedOtherComprehensiveIncomeLossAvailableForSaleSecuritiesAdjustmentNetOfTax
Other Investments [Member]    
Schedule of Investments [Line Items]    
Investments in available-for-sale securities and other cost investments 47us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_OtherInvestmentsMember
47us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_OtherInvestmentsMember
AFS and cost method investments    
Schedule of Investments [Line Items]    
Investments in available-for-sale securities and other cost investments 71us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= lmca_AfsAndCostMethodInvestmentsMember
71us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= lmca_AfsAndCostMethodInvestmentsMember
Viacom, Inc.    
Schedule of Investments [Line Items]    
Available for sale securities number of shares sold 1.3lmca_AvailableForSaleSecuritiesNumberOfSharesSold
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_ViacomIncMember
 
Proceeds from Sale of Available-for-sale Securities 86us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_ViacomIncMember
 
Barnes & Noble, Inc.    
Schedule of Investments [Line Items]    
Proceeds from Sale of Available-for-sale Securities 27us-gaap_ProceedsFromSaleOfAvailableForSaleSecurities
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_BarnesNobleIncMember
 
Live Nation | Debt Securities    
Schedule of Investments [Line Items]    
Investments in available-for-sale securities and other cost investments 24us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_LiveNationMember
24us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_LiveNationMember
Fair Value Option Securities    
Schedule of Investments [Line Items]    
Investments in available-for-sale securities and other cost investments 600us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= lmca_FairValueOptionSecuritiesMember
745us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= lmca_FairValueOptionSecuritiesMember
Fair Value Option Securities | Time Warner Inc | Equity Securities    
Schedule of Investments [Line Items]    
Investments in available-for-sale securities and other cost investments 359us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= lmca_FairValueOptionSecuritiesMember
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_TimeWarnerIncMember
363us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= lmca_FairValueOptionSecuritiesMember
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_TimeWarnerIncMember
Fair Value Option Securities | Viacom, Inc. | Equity Securities    
Schedule of Investments [Line Items]    
Investments in available-for-sale securities and other cost investments 162us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= lmca_FairValueOptionSecuritiesMember
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_ViacomIncMember
273us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= lmca_FairValueOptionSecuritiesMember
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_ViacomIncMember
Fair Value Option Securities | Barnes & Noble, Inc. | Equity Securities    
Schedule of Investments [Line Items]    
Investments in available-for-sale securities and other cost investments   27us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= lmca_FairValueOptionSecuritiesMember
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_BarnesNobleIncMember
Fair Value Option Securities | Other AFS Equity Securities | Equity Securities    
Schedule of Investments [Line Items]    
Investments in available-for-sale securities and other cost investments 54us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= lmca_FairValueOptionSecuritiesMember
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_OtherAfsEquitySecuritiesMember
55us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= lmca_FairValueOptionSecuritiesMember
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_EquitySecuritiesMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_OtherAfsEquitySecuritiesMember
Fair Value Option Securities | Other AFS Debt Securities | Debt Securities    
Schedule of Investments [Line Items]    
Investments in available-for-sale securities and other cost investments $ 25us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= lmca_FairValueOptionSecuritiesMember
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_OtherAfsDebtSecuritiesMember
$ 27us-gaap_AvailableForSaleSecuritiesNoncurrent
/ us-gaap_EligibleItemOrGroupForFairValueOptionAxis
= lmca_FairValueOptionSecuritiesMember
/ us-gaap_MajorTypesOfDebtAndEquitySecuritiesAxis
= us-gaap_DebtSecuritiesMember
/ us-gaap_ScheduleOfEquityMethodInvestmentEquityMethodInvesteeNameAxis
= lmca_OtherAfsDebtSecuritiesMember