Document and Entity Information Document (USD $)	12 Months Ended
	Dec. 31, 2014	Jun. 30, 2014	Feb. 06, 2015
Document Information [Line Items]
Entity Registrant Name	MOLSON COORS BREWING CO
Trading Symbol	tap
Entity Central Index Key	0000024545
Document Type	10-K
Document Period End Date	Dec. 31, 2014
Document Fiscal Year Focus	2014
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--12-31
Amendment Flag	false
Entity Filer Category	Large Accelerated Filer
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Public Float		$ 11,119,177,834
Class A common stock, voting
Document Information [Line Items]
Entity Common Stock, shares outstanding			2,559,794
Class B common stock, non-voting
Document Information [Line Items]
Entity Common Stock, shares outstanding			162,861,262
Class A exchangeable shares
Document Information [Line Items]
Entity Common Stock, shares outstanding			2,894,040
Class B exchangeable shares
Document Information [Line Items]
Entity Common Stock, shares outstanding			17,567,143