Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity (Details)

v2.4.1.9
Stockholders' Equity (Details) (USD $)
In Millions, except Share data, unless otherwise specified
0 Months Ended 1 Months Ended 3 Months Ended 12 Months Ended 0 Months Ended
Oct. 03, 2013
Oct. 31, 2013
Dec. 31, 2013
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jul. 23, 2014
Preferred stock, shares issued     0us-gaap_PreferredStockSharesIssued 0us-gaap_PreferredStockSharesIssued 0us-gaap_PreferredStockSharesIssued    
Share-based Compensation Arrangement by Share-based Payment Award, Options, Exercises in Period, Total Intrinsic Value       $ 17us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue $ 23us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue $ 494us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsExercisesInPeriodTotalIntrinsicValue  
Stock Repurchased and Retired During Period, Shares       0us-gaap_StockRepurchasedAndRetiredDuringPeriodShares      
Payments for Repurchase of Common Stock         140us-gaap_PaymentsForRepurchaseOfCommonStock 323us-gaap_PaymentsForRepurchaseOfCommonStock  
Shares retired   6,300,000us-gaap_TreasuryStockSharesRetired          
Cash paid in exchange transaction     417lmca_Cashincludedinexchangetransaction   429lmca_Cashincludedinexchangetransaction    
Nonmonetary Transaction, Gain (Loss) Recognized on Transfer 496us-gaap_NonmonetaryTransactionGainLossRecognizedOnTransfer       (496)us-gaap_NonmonetaryTransactionGainLossRecognizedOnTransfer    
Common Class A              
Votes per share       1lmca_NumberOfVotesPerShare
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
     
Number of shares received in exchange for a share of Series B       1lmca_CommonSharesReceivedInExchangeForOneShareOfSeriesB
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
     
Stock reserved for future issuance       3,200,000us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
     
Stock Repurchased and Retired During Period, Shares         1,264,550us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
3,591,271us-gaap_StockRepurchasedAndRetiredDuringPeriodShares
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
 
Payments for Repurchase of Common Stock         $ 140us-gaap_PaymentsForRepurchaseOfCommonStock
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
$ 323us-gaap_PaymentsForRepurchaseOfCommonStock
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
 
Common Stock, Shares Authorized     2,000,000,000us-gaap_CommonStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
2,000,000,000us-gaap_CommonStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
2,000,000,000us-gaap_CommonStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassAMember
   
Common Class B              
Votes per share       10lmca_NumberOfVotesPerShare
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
     
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number       0us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardOptionsOutstandingNumber
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
     
Common Stock, Shares Authorized     75,000,000us-gaap_CommonStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
75,000,000us-gaap_CommonStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
75,000,000us-gaap_CommonStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassBMember
   
Common Class C              
Shares received in exchange             2lmca_NumberofsharesissuedduringtheperiodforeachshareofSeriesAandSeriesBstockheldbyshareholderspriortothedistribution
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassCMember
Votes per share       0lmca_NumberOfVotesPerShare
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassCMember
     
Stock reserved for future issuance       9,800,000us-gaap_CommonStockCapitalSharesReservedForFutureIssuance
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassCMember
     
Common Stock, Shares Authorized     2,000,000,000us-gaap_CommonStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassCMember
2,000,000,000us-gaap_CommonStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassCMember
2,000,000,000us-gaap_CommonStockSharesAuthorized
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassCMember