Annual report pursuant to Section 13 and 15(d)

Stockholders' Equity (Details)

v3.8.0.1
Stockholders' Equity (Details)
$ / shares in Units, $ in Millions
 1 Months Ended 12 Months Ended
Oct. 03, 2017
USD ($)
shares
Mar. 31, 2017
USD ($)
Dec. 31, 2016
$ / shares
shares
May 18, 2016
USD ($)
$ / shares
shares
Jan. 09, 2015
shares
Dec. 10, 2014
$ / shares
Nov. 04, 2014
shares
Oct. 29, 2014
Aug. 31, 2017
USD ($)
Apr. 30, 2017
USD ($)
shares
Mar. 31, 2017
USD ($)
Dec. 31, 2016
USD ($)
$ / shares
shares
May 31, 2016
shares
Dec. 31, 2017
Vote
item
$ / shares
$ / item
shares
Broadband Spin-Off Distribution Ratio               0.25            
Shares issued during period             85,761,332              
Common Stock, Capital Shares Reserved for Future Issuance                           2,800,000
Zero-strike call option                            
Derivative underlying share amount 527,156                          
Derivative premium paid | $ $ 47.7                     $ 47.9    
Derivative settlement proceeds | $   $ 50.0             $ 53.8   $ 50.0      
Liberty Interactive                            
Number of shares purchased                         42,700,000  
Non-voting economic ownership percentage     23.50%                      
Series A common stock                            
Common Stock, Par or Stated Value Per Share | $ / shares     $ 0.01                 $ 0.01   $ 0.01
Number Of Votes | Vote                           1
Common Stock, Capital Shares Reserved for Future Issuance                           404,000
Series B common stock                            
Common Stock, Par or Stated Value Per Share | $ / shares     0.01                 0.01   $ 0.01
Number Of Votes | Vote                           10
Common Stock Shares Received In Exchange For One Share Of Series B | item                           1
Series C common stock                            
Subscription Rights Distribution Ratio           0.20                
Proceeds from Issuance of Common Stock | $       $ 4,400.0                    
Shares issued during period       78,250,042 17,277,224                  
Common Stock, Par or Stated Value Per Share | $ / shares     $ 0.01 $ 0.01               $ 0.01   $ 0.01
Purchase price (in dollars per share) | $ / shares       $ 56.23   $ 40.36                
Discount percentage for holders to acquire shares enabled by subscription rights           20.00%                
Number of trading days of volume weighted average trading price used for calculating discount for holders to acquire shares enabled by subscription rights           20 days                
Number Of Votes | Vote                           0
Common Stock, Capital Shares Reserved for Future Issuance                           2,400,000
Series C common stock | Zero-strike call option                            
Derivative underlying share amount     704,908                 704,908    
Call Option | Zero-strike call option                            
Derivative underlying share amount 527,156   704,908             600,242   704,908    
Derivative, Price Risk Option Strike Price | $ / item                           90.54
Derivative premium paid | $ $ 47.7                 $ 50.0   $ 47.9