Annual report pursuant to Section 13 and 15(d)

Investments in Debt and Equity Securities - Summary (Details)

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Investments in Debt and Equity Securities - Summary (Details)
$ / shares in Units, $ in Millions
12 Months Ended
Feb. 01, 2019
USD ($)
$ / shares
Sep. 22, 2017
USD ($)
$ / shares
shares
Dec. 31, 2018
USD ($)
Dec. 31, 2017
USD ($)
item
Dec. 31, 2016
USD ($)
Investments in Debt and Equity Securities          
Consolidated Liberty     $ 1,278 $ 1,114  
Payments to Acquire Investments     $ 414 862 $ 784
SIRIUS XM          
Investments in Debt and Equity Securities          
Ownership Interest In Investee 67.00%   73.00%    
Business acquisition          
Common stock, par or stated value per share | $ / shares $ 0.001        
Pandora | SIRIUS XM          
Investments in Debt and Equity Securities          
Unrealized gain (loss) on securities     $ 28 $ (17)  
Payments to Acquire Investments   $ 480      
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  
Business acquisition          
Initial value of all-stock transaction $ 2,900        
Common stock, par or stated value per share | $ / shares $ 0.0001        
Number of shares of common stock issued for each share of acquired entity's stock 1.44        
SIRIUS XM          
Investments in Debt and Equity Securities          
Ownership Interest In Investee 67.00%        
Liberty Sirius XM Group          
Investments in Debt and Equity Securities          
Consolidated Liberty     967 $ 580  
Payments to Acquire Investments     405 851  
Liberty Sirius XM Group | Debt Securities          
Investments in Debt and Equity Securities          
Debt securities     967 580  
Liberty Sirius XM Group | Pandora | Debt Securities          
Investments in Debt and Equity Securities          
Debt securities     523 480  
Liberty Sirius XM Group | iHeart          
Investments in Debt and Equity Securities          
Principal amount of debt securities acquired during period     522    
Payments to acquire debt securities     389    
Debt security, principal balance     660    
Liberty Sirius XM Group | iHeart | Debt Securities          
Investments in Debt and Equity Securities          
Debt securities     444 100  
Braves Group          
Investments in Debt and Equity Securities          
Other equity securities     8 8  
Consolidated Liberty     8 8  
Payments to Acquire Investments       2 20
Braves Group | Other Equity Securities          
Investments in Debt and Equity Securities          
Other equity securities     8 8  
Formula One Group          
Investments in Debt and Equity Securities          
Consolidated Liberty     303 526  
Payments to Acquire Investments     9 9 $ 764
Formula One Group | Equity Securities          
Investments in Debt and Equity Securities          
Equity securities     303 526  
Formula One Group | AT&T | Equity Securities          
Investments in Debt and Equity Securities          
Equity securities     174 389  
Formula One Group | Other Equity Securities | Equity Securities          
Investments in Debt and Equity Securities          
Equity securities     $ 129 $ 137