| Investments In Affiliates Accounted For Using The Equity Method (Schedule Of Equity Ownership And Carrying Amount) (Details) (USD $) In Millions, unless otherwise specified | 3 Months Ended | ||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Jun. 30, 2013 | Dec. 31, 2012 | Dec. 31, 2012
 SIRIUS XM [Member] | Jun. 30, 2013
 Charter Communications [Member] | May 01, 2013
 Charter Communications [Member] | Mar. 31, 2013
 Live Nation [Member] | Jun. 30, 2013
 Live Nation [Member] | Dec. 31, 2012
 Live Nation [Member] | Jun. 30, 2013
 Sirius XM Canada [Member] | Jun. 30, 2013
 Equity method investment, other [Member] | Dec. 31, 2012
 Equity method investment, other [Member] | |||||||||||||||
| Payments to Acquire Equity Method Investments | $ 19 | ||||||||||||||||||||||||
| Percentage ownership | 27.00% | [1] | 27.00% | 27.00% | [2] | 27.00% | [2] | 38.00% | [3] | ||||||||||||||||
| Investments in affiliates, accounted for using the equity method (note 7) | 3,415 | 3,341 | 2,766 | [3] | 2,528 | [3] | 405 | [2] | 406 | [2] | 278 | [3] | 204 | 169 | |||||||||||
| Equity Method Investment, Quoted Market Value | $ 3,326 | [4] | $ 807 | [4] | $ 308 | ||||||||||||||||||||
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