Quarterly report pursuant to Section 13 or 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
9 Months Ended
Sep. 23, 2018
USD ($)
$ / shares
Sep. 30, 2018
USD ($)
Dec. 31, 2017
USD ($)
Transaction details [Line Items]      
Consolidated Liberty   $ 1,406 $ 1,114
SIRIUS XM      
Business acquisition      
Common stock, par or stated value per share | $ / shares $ 0.001    
SIRIUS XM | Pandora      
Business acquisition      
Initial value of all-stock transaction $ 3,500    
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    
Liberty Sirius XM Group      
Transaction details [Line Items]      
Debt securities   1,050 580
Consolidated Liberty   1,050  
Liberty Sirius XM Group | Pandora | Debt Securities      
Transaction details [Line Items]      
Debt securities   554 480
Liberty Sirius XM Group | iHeart      
Transaction details [Line Items]      
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      
Transaction details [Line Items]      
Debt securities   496 100
Braves Group      
Transaction details [Line Items]      
Other equity securities   8 8
Consolidated Liberty   8  
Braves Group | Other Equity Securities | Equity Securities      
Transaction details [Line Items]      
Other equity securities   8 8
Formula One Group      
Transaction details [Line Items]      
Other equity securities   348 526
Consolidated Liberty   348  
Formula One Group | AT&T | Equity Securities      
Transaction details [Line Items]      
Equity securities   205 389
Formula One Group | Other Equity Securities | Equity Securities      
Transaction details [Line Items]      
Other equity securities   $ 143 $ 137