Annual report pursuant to Section 13 and 15(d)

Basis of Presentation (Details)

Basis of Presentation (Details) (USD $)
In Millions, except Share data, unless otherwise specified
1 Months Ended 12 Months Ended 0 Months Ended
Oct. 31, 2014
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Jul. 23, 2014
Oct. 17, 2013
Entity Information [Line Items]            
Class of Warrant or Right, Exercise Price of Warrants or Rights           $ 255.64us-gaap_ClassOfWarrantOrRightExercisePriceOfWarrantsOrRights1
Cash received from consolidated subsidiary $ 300lmca_CashReceivedFromConsolidatedSubsidiary          
Related Party Transaction, Amounts of Transaction   15us-gaap_RelatedPartyTransactionAmountsOfTransaction 16us-gaap_RelatedPartyTransactionAmountsOfTransaction 10us-gaap_RelatedPartyTransactionAmountsOfTransaction    
Starz, LLC            
Entity Information [Line Items]            
Related Party Transaction, Amounts of Transaction   $ 3us-gaap_RelatedPartyTransactionAmountsOfTransaction
/ us-gaap_RelatedPartyTransactionsByRelatedPartyAxis
= lmca_StarzLlcMember
Common Class C            
Entity Information [Line Items]            
Number of shares issued during the period for each share of Series A and Series B stock held by shareholders prior to the distribution         2lmca_NumberofsharesissuedduringtheperiodforeachshareofSeriesAandSeriesBstockheldbyshareholderspriortothedistribution
/ us-gaap_StatementClassOfStockAxis
= us-gaap_CommonClassCMember