| 
           Summary of Significant Accounting Policies (Details) 
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           Sep. 30, 2014
 
          USD ($) 
         | 
        
           Dec. 31, 2013
 
          USD ($) 
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           Sep. 30, 2014
 
          Level 2 [Member]
 
          USD ($) 
         | 
        
           Dec. 31, 2013
 
          Level 2 [Member]
 
          USD ($) 
         | 
        
           Sep. 30, 2014
 
          Sirius XM Canada [Member]
 
          USD ($) 
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           Dec. 31, 2013
 
          Sirius XM Canada [Member]
 
          USD ($) 
         | 
        
           Sep. 30, 2014
 
          Sirius XM Canada [Member]
 
          Level 1 [Member]
 
          USD ($) 
         | 
        
           Dec. 31, 2013
 
          Sirius XM Canada [Member]
 
          Level 1 [Member]
 
          USD ($) 
         | 
        
           Sep. 30, 2014
 
          Sirius XM Canada [Member]
 
          Level 3 [Member]
 
          USD ($) 
         | 
        
           Dec. 31, 2013
 
          Sirius XM Canada [Member]
 
          Level 3 [Member]
 
          USD ($) 
         | 
        
           Sep. 30, 2014
 
          Related Party Current Liabilities [Member]
 
          Liberty Media [Member]
 
          USD ($) 
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           Dec. 31, 2013
 
          Related Party Current Liabilities [Member]
 
          Liberty Media [Member]
 
          USD ($) 
         | 
        
           Sep. 30, 2014
 
          Related Party Current Liabilities [Member]
 
          Liberty Media [Member]
 
          Level 2 [Member]
 
          USD ($) 
         | 
        
           Dec. 31, 2013
 
          Related Party Current Liabilities [Member]
 
          Liberty Media [Member]
 
          Level 2 [Member]
 
          USD ($) 
         | 
        
           Dec. 31, 2013
 
          8% Convertible Unsecured Subordinated Debentures [Member]
 
          Sirius XM Canada [Member]
 
          CAD 
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|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Assets | |||||||||||||||||||||||||||||||||||||
| Investment balance, fair value | $ 303,500,000 | [1] | $ 432,200,000 | [1] | $ 303,500,000 | [1] | $ 432,200,000 | [1] | |||||||||||||||||||||||||||||
| Fair value of host contract of debenture | 0 | [2] | 3,641,000 | [2] | 0 | [2] | 3,641,000 | [2] | |||||||||||||||||||||||||||||
| Fair Value of Embedded Derivative Related to Investment in Debenture, Current | 0 | [2] | 57,000 | [2] | 0 | [2] | 57,000 | [2] | |||||||||||||||||||||||||||||
| Liabilities | |||||||||||||||||||||||||||||||||||||
| Debt, fair value | 5,270,623,000 | [3] | 4,066,755,000 | [3] | 5,270,623,000 | [3] | 4,066,755,000 | [3] | |||||||||||||||||||||||||||||
| Derivatives asset (liability), fair value | 0 | [4] | 15,702,000 | [4] | 0 | [4] | 15,702,000 | [4] | |||||||||||||||||||||||||||||
| Investment balance, carrying value | 1,292,000 | 26,972,000 | |||||||||||||||||||||||||||||||||||
| Investment in related party debt | 4,000,000 | ||||||||||||||||||||||||||||||||||||
| Interest rate on instrument | 8.00% | ||||||||||||||||||||||||||||||||||||
          
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