Document and Entity Information	9 Months Ended
	Sep. 30, 2013	Oct. 31, 2013 Class A Common Stock	Oct. 31, 2013 Class B Common Stock
Document And Entity Information [Abstract]
Entity registrant name	CBS Corporation
Entity central index key	0000813828
Document type	10-Q
Document period end date	Sep. 30, 2013
Amendment flag	false
Current fiscal year end date	--12-31
Entity filer category	Large Accelerated Filer
Document fiscal year focus	2013
Document fiscal period focus	Q3
Statement [Line Items]
Entity common stock, shares outstanding		39,240,440	560,843,520