Document and Entity Information	3 Months Ended
	Mar. 31, 2012	Apr. 27, 2012
Document and Entity Information [Abstract]
Entity Registrant Name	SIRIUS XM RADIO INC.
Entity Central Index Key	0000908937
Document Type	10-Q
Document Period End Date	Mar. 31, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q1
Amendment Flag	false
Current Fiscal Year End Date	--12-31
Entity Current Reporting Status	Yes
Entity Filer Category	Large Accelerated Filer
Entity Common Stock, Shares Outstanding		3,801,029,929
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No