| Property and Equipment | 9 Months Ended | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
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| Sep. 30, 2025 | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Property, Plant and Equipment [Abstract] | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| Property and Equipment | Property and Equipment Property and equipment, net, consists of the following:  
 Construction in progress consists of the following:  
 Depreciation and amortization expense on property and equipment was $110 and $113 for the three months ended September 30, 2025 and 2024, respectively, and $313 and $354 for the nine months ended September 30, 2025 and 2024, respectively.  During the three and nine months ended September 30, 2024, we retired property and equipment of $3 and $58, respectively.  Refer to Note 4 for information regarding impairment charges recorded on our property and equipment during the three and nine months ended September 30, 2025 and 2024. We capitalize a portion of the interest on funds borrowed to finance the construction and launch of our satellites. Capitalized interest is recorded as part of the asset’s cost and depreciated over the satellite’s useful life.  Capitalized interest costs were $5 and $7 for the three months ended September 30, 2025 and 2024, respectively, and $18 and $19 for the nine months ended September 30, 2025 and 2024, respectively, which related to the construction of our SXM-9 satellite, which launched in December 2024, and our SXM-10, SXM-11 and SXM-12 satellites.  We also capitalize a portion of share-based compensation related to employee time for capitalized software projects.  Capitalized share-based compensation costs were $11 and $7 for the three months ended September 30, 2025 and 2024, respectively, and $31 and $19 for the nine months ended September 30, 2025 and 2024, respectively.   Satellites As of September 30, 2025, we operated a fleet of six satellites.  Each satellite requires an FCC license, and prior to the expiration of each license, we are required to apply for a renewal of the FCC satellite license.  The renewal and extension of our licenses is reasonably certain at minimal cost, which is expensed as incurred.  The chart below provides certain information on our satellites as of September 30, 2025: 
 In January 2025 and July 2025, our SXM-9 and SXM-10 satellites, respectively, successfully completed in-orbit testing and were placed into service.  Our SXM-9 and SXM-10 satellites replaced our SXM-8 and FM-6 satellites, respectively, with both becoming in-orbit spares.  During the three months ended March 31, 2025, we removed our XM-3 satellite from service and are in the process of de-orbiting the satellite, which we expect to be completed by the end of 2025.  Our SXM-11 and SXM-12 satellites, which are currently under construction, are expected to replace our XM-5 and Sirius FM-5 satellites. | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||