| Goodwill and Other Intangible Assets (Goodwill) (Details) - USD ($) $ in Millions | 9 Months Ended | |
|---|---|---|
| Apr. 18, 2017 | Sep. 30, 2017 | |
| Goodwill [Roll Forward] | ||
| Goodwill, Beginning Balance | $ 14,345 | |
| Acquisitions | 4,050 | |
| Goodwill, Ending Balance | 18,395 | |
| Business acquisition | ||
| Purchase Price | 1,647 | |
| SIRIUS XM | ||
| Goodwill [Roll Forward] | ||
| Goodwill, Beginning Balance | 14,165 | |
| Acquisitions | 82 | |
| Goodwill, Ending Balance | 14,247 | |
| Formula 1 | ||
| Goodwill [Roll Forward] | ||
| Acquisitions | 3,968 | |
| Goodwill, Ending Balance | 3,968 | |
| Corporate And Other | ||
| Goodwill [Roll Forward] | ||
| Goodwill, Beginning Balance | 180 | |
| Goodwill, Ending Balance | $ 180 | |
| Automatic Labs Inc. | ||
| Business acquisition | ||
| Purchase Price | $ 108 | 
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- Definition Amount after accumulated impairment loss of an asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition Amount of increase in asset representing future economic benefits arising from other assets acquired in a business combination that are not individually identified and separately recognized resulting from a business combination. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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- Definition A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period. No definition available. 
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- Definition The cash outflow associated with the acquisition of a business, net of the cash acquired from the purchase. Reference 1: http://www.xbrl.org/2003/role/presentationRef 
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