Annual report pursuant to Section 13 and 15(d)

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

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Investments In Available-For-Sale Securities And Other Cost Investments (Details)
$ / shares in Units, $ in Millions
12 Months Ended
Sep. 22, 2017
USD ($)
$ / shares
shares
Dec. 31, 2017
USD ($)
item
Dec. 31, 2016
USD ($)
Dec. 31, 2015
USD ($)
Transaction details [Line Items]        
Investments in available-for-sale securities and other cost investments   $ 1,114 $ 1,309  
Payments to Acquire Investments   862 784 $ 19
Unrealized Gain (Loss) on Securities   $ (88) 37 (140)
SIRIUS XM        
Transaction details [Line Items]        
Ownership Interest In Investee   70.00%    
Pandora        
Transaction details [Line Items]        
Payments to Acquire Investments $ 480      
Pandora | SIRIUS XM        
Transaction details [Line Items]        
Ownership Interest In Investee 19.00%      
Ownership percentage on an as-converted basis 16.00%      
Convertible Preferred Stock, Price Per Share | $ / shares $ 10.50      
Convertible Preferred Stock, Shares Issued upon Conversion | shares 95.2381      
Preferred Stock, Dividend Rate, Percentage 6.00%      
Cost Method Investment Minimum Threshold Percentage Approved Issuance 19.99      
Cost Method Investment Maximum Percentage Threshold For Conversion Of Preferred Shares 19.99%      
Cost Method Investment, Number of Directors Designated | item   3    
Cost Method Investment, Number of Directors Designated, Chairman | item   1    
Unrealized Gain (Loss) on Securities   $ (17)    
Pandora | SIRIUS XM | Minimum        
Transaction details [Line Items]        
Cost Method Investment, Minimum Ownerships Percentage for Director Designation, Converted Basis   50.00%    
Cost Method Investment, Minimum Ownership Percentage for Designation of Two Directors, Converted Basis   75.00%    
Other AFS Securities | Fair Value Option Securities        
Transaction details [Line Items]        
Investments in available-for-sale securities and other cost investments   $ 100    
Liberty Sirius XM Group        
Transaction details [Line Items]        
Investments in available-for-sale securities and other cost investments   580    
Payments to Acquire Investments   851    
Unrealized Gain (Loss) on Securities   (16)    
Liberty Sirius XM Group | Pandora | Fair Value Option Securities        
Transaction details [Line Items]        
Investments in available-for-sale securities and other cost investments   480    
Braves Group        
Transaction details [Line Items]        
Investments in available-for-sale securities and other cost investments   8 8  
Payments to Acquire Investments   2 20  
Unrealized Gain (Loss) on Securities     1  
Braves Group | AFS and cost method investments        
Transaction details [Line Items]        
Investments in available-for-sale securities and other cost investments   8 8  
Formula One Group        
Transaction details [Line Items]        
Investments in available-for-sale securities and other cost investments   526 1,301  
Payments to Acquire Investments   9 764 19
Unrealized Gain (Loss) on Securities   (72) 36 $ (140)
Formula One Group | Fair Value Option Securities        
Transaction details [Line Items]        
Investments in available-for-sale securities and other cost investments   467 489  
Formula One Group | AFS and cost method investments        
Transaction details [Line Items]        
Investments in available-for-sale securities and other cost investments   59 812  
Formula One Group | Time Warner Inc | Fair Value Option Securities        
Transaction details [Line Items]        
Investments in available-for-sale securities and other cost investments   389 411  
Formula One Group | Formula 1 | AFS and cost method investments        
Transaction details [Line Items]        
Investments in available-for-sale securities and other cost investments     759  
Formula One Group | Other AFS Securities | Fair Value Option Securities        
Transaction details [Line Items]        
Investments in available-for-sale securities and other cost investments   78 78  
Formula One Group | Other AFS Securities | AFS and cost method investments        
Transaction details [Line Items]        
Investments in available-for-sale securities and other cost investments   $ 59 $ 53