Document and Entity Information	3 Months Ended
	Mar. 31, 2013	Apr. 26, 2013 Class A Common Stock	Apr. 26, 2013 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, 2013
Document fiscal year focus	2013
Document fiscal period focus	Q1
Current fiscal year end date	--12-31
Amendment flag	false
Statement [Line Items]
Entity common stock, shares outstanding		41,497,888	572,090,859