Document and Entity Information	3 Months Ended
	Mar. 31, 2012	Apr. 30, 2012 Class A Common Stock	Apr. 30, 2012 Class B Common Stock
Document And Entity Information [Abstract]
Entity Registrant Name	CBS Corporation
Entity Central Index Key	0000813828
Entity Filer Category	Large Accelerated Filer
Document Type	10-Q
Document Period End Date	Mar. 31, 2012
Document Fiscal Year Focus	2012
Document Fiscal Period Focus	Q1
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Statement [Line Items]
Entity Common Stock, Shares Outstanding		43,444,102	604,697,329