Debt Long Term Borrowings (Details)	3 Months Ended	12 Months Ended								3 Months Ended					12 Months Ended	0 Months Ended		0 Months Ended			12 Months Ended			3 Months Ended			12 Months Ended																									12 Months Ended						0 Months Ended									6 Months Ended	12 Months Ended										12 Months Ended		3 Months Ended	12 Months Ended
	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)		Dec. 31, 2013 USD ($)		Dec. 29, 2012 USD ($)	Dec. 31, 2014 Central Europe USD ($)	Sep. 30, 2014 Central Europe EUR (€)	Sep. 10, 2012 Central Europe EUR (€)	Sep. 30, 2010 Foreign currency forwards CAD	Sep. 25, 2005 Foreign currency forwards CAD	Oct. 06, 2010 Foreign currency forwards CAD	Sep. 25, 2010 Foreign currency forwards	Sep. 22, 2005 Foreign currency forwards CAD	Dec. 29, 2012 Treasury Lock Loss Interest Rate Contract USD ($)	May 03, 2012 Convertible Senior Unsecured Note Due 2013 €500 Million 0.0% [Member] Treasury Lock Loss Interest Rate Contract	Jun. 25, 2011 Revolving Multicurrency Bank Credit Facility USD ($)	Jun. 15, 2012 Molson Coors Central Europe (MCCE) USD ($)	Jun. 15, 2012 Molson Coors Central Europe (MCCE) EUR (€)	Dec. 31, 2013 Revolving Credit Facility USD ($)	Dec. 29, 2012 Senior Notes USD ($)	May 03, 2012 Senior Notes USD ($)	Oct. 06, 2010 Senior Notes USD ($)	Jun. 30, 2012 Senior Notes Bridge facility fees USD ($)	Dec. 31, 2014 Senior Notes $575 million 2.5% convertible Senior Notes due 2013	Jun. 15, 2007 Senior Notes $575 million 2.5% convertible Senior Notes due 2013 USD ($)	Dec. 31, 2013 Senior Notes Convertible Senior Unsecured Note Due 2013 €500 Million 0.0% [Member] USD ($)	Dec. 29, 2012 Senior Notes Convertible Senior Unsecured Note Due 2013 €500 Million 0.0% [Member] USD ($)	Dec. 31, 2014 Senior Notes Convertible Senior Unsecured Note Due 2013 €500 Million 0.0% [Member] USD ($)	Dec. 31, 2014 Senior Notes Canadian dollar ("CAD") 900 million 5.0% notes due 2015 USD ($)		Dec. 31, 2014 Senior Notes Canadian dollar ("CAD") 900 million 5.0% notes due 2015 CAD		Dec. 31, 2013 Senior Notes Canadian dollar ("CAD") 900 million 5.0% notes due 2015 USD ($)		Dec. 31, 2014 Senior Notes CAD 500 million 3.95% Series A notes due 2017 USD ($)		Dec. 31, 2014 Senior Notes CAD 500 million 3.95% Series A notes due 2017 CAD		Dec. 31, 2013 Senior Notes CAD 500 million 3.95% Series A notes due 2017 USD ($)		Dec. 31, 2014 Senior Notes $300 million 2.0% notes due 2017 USD ($)		Dec. 31, 2013 Senior Notes $300 million 2.0% notes due 2017 USD ($)		May 03, 2012 Senior Notes $300 million 2.0% notes due 2017 USD ($)	Dec. 31, 2014 Senior Notes $500 million 3.5% notes due 2022 USD ($)		Dec. 31, 2013 Senior Notes $500 million 3.5% notes due 2022 USD ($)		May 03, 2012 Senior Notes $500 million 3.5% notes due 2022 USD ($)	Dec. 29, 2012 Senior Notes $1.1 billion 5.0% notes due 2042 USD ($)	Dec. 31, 2014 Senior Notes $1.1 billion 5.0% notes due 2042 USD ($)		Dec. 31, 2013 Senior Notes $1.1 billion 5.0% notes due 2042 USD ($)		May 03, 2012 Senior Notes $1.1 billion 5.0% notes due 2042 USD ($)	Jun. 15, 2012 Senior Notes Molson Coors Central Europe (MCCE) USD ($)		Apr. 03, 2012 Term Loan Agreement	Jun. 15, 2012 Convertible Debt Molson Coors Central Europe (MCCE) USD ($)		Sep. 03, 2013 Convertible Debt Molson Coors Central Europe (MCCE) Convertible Senior Unsecured Note Due 2013 €500 Million 0.0% [Member] USD ($)	Sep. 03, 2013 Convertible Debt Molson Coors Central Europe (MCCE) Convertible Senior Unsecured Note Due 2013 €500 Million 0.0% [Member] EUR (€)	Aug. 13, 2013 Convertible Debt Molson Coors Central Europe (MCCE) Convertible Senior Unsecured Note Due 2013 €500 Million 0.0% [Member] EUR (€)	Jun. 15, 2012 Convertible Debt Molson Coors Central Europe (MCCE) Convertible Senior Unsecured Note Due 2013 €500 Million 0.0% [Member] EUR (€)	Jun. 30, 2014 Convertible Debt Molson Coors Central Europe (MCCE) Convertible Senior Unsecured Note Due 2013 €500 Million 0.0% [Member] USD ($)	Dec. 31, 2014 Convertible Debt Molson Coors Central Europe (MCCE) Convertible Senior Unsecured Note Due 2013 €500 Million 0.0% [Member] USD ($)	Dec. 31, 2014 Convertible Debt Molson Coors Central Europe (MCCE) Convertible Senior Unsecured Note Due 2013 €500 Million 0.0% [Member] EUR (€)	Jun. 30, 2012 Line of Credit USD ($)	Jun. 30, 2014 Commercial Paper Program USD ($)	Mar. 30, 2013 Commercial Paper Program USD ($)	Dec. 31, 2014 Japan, Yen Line of Credit USD ($)	Dec. 31, 2013 Japan, Yen Line of Credit USD ($)	Dec. 31, 2014 Euro Member Countries, Euro Line of Credit USD ($)	Dec. 31, 2013 Euro Member Countries, Euro Line of Credit USD ($)	Dec. 31, 2014 Year To Date Senior Notes $500 million 3.5% notes due 2022	Dec. 31, 2014 Interest rate swaps Senior Notes $500 million 3.5% notes due 2022 USD ($)	Jun. 30, 2014 Letter of Credit USD ($)	Jun. 30, 2014 Revolving Credit Facility USD ($)	Dec. 31, 2014 Fair Value Hedging USD ($)	Dec. 31, 2014 Fair Value Hedging Interest expense, net Forward starting interest rate swaps USD ($)
Debt Instrument [Line Items]
Long-term debt, gross																											$ 61,800,000		$ 0	$ 774,500,000	[1]	900,000,000	[1]	$ 847,200,000	[1]	$ 430,300,000	[1]	500,000,000	[1]	$ 470,700,000	[1]	$ 300,000,000	[2]	$ 300,000,000	[2]		$ 510,800,000	[2]	$ 500,000,000	[2]			$ 1,100,000,000	[2]	$ 1,100,000,000	[2]
Other long-term debt		0		200,000
Long-term credit facilities		0	[3]	0	[3]
Less: unamortized debt discounts and other		(4,200,000)	[4]	(5,100,000)	[4]
Total long-term debt (including current portion)		3,111,400,000		3,274,800,000
Current portion of long-term debt		774,300,000		61,800,000
Long-term debt		2,337,100,000		3,213,000,000
Short-term Debt																																																																									4,900,000	3,100,000	0	137,400,000
Other Short-term borrowings		5,600,000		4,800,000
Commercial Paper		0		379,800,000
Bank Overdrafts		64,600,000		0			64,600,000
Current portion of long-term debt and short-term borrowings		849,400,000		586,900,000
Debt Instruments [Abstract]
Debt instrument, face amount												500,000,000		900,000,000								1,900,000,000	500,000,000			575,000,000																				300,000,000					500,000,000						1,100,000,000
Change in unrealized gain (loss) on hedged item in fair value hedge																																																																																	10,800,000	10,800,000
Increase in fair value of hedged item in interest rate fair value hedge																																																																														10,800,000
Debt Instrument Increase in Effective Cost of Borrowing Expressed as Basis Points over Stated Coupon, Rate													0.23%	0.05%
Derivative, Loss on Derivative										7,800,000	4,000,000
Debt instrument, interest rate percentage																													0.00%	5.00%		5.00%				3.95%		3.95%				2.00%				2.00%	3.50%				3.50%		5.00%				5.00%
Debt instrument, term																																																												4 years
Less: unamortized debt discounts and other		(4,200,000)	[4]	(5,100,000)	[4]
Convertible debt, interest expense		145,000,000		183,800,000		196,300,000
Debt instrument, effective interest rate																																																																													3.13%
Business acquisition, cost of acquired entity, liabilities incurred																		3,400,000,000	2,700,000,000																																							585,000,000	[5]		645,900,000	[6]				500,000,000
Business Combination, Payment of Claim Settlement																																																																			61,400,000
Convertible debt, settlement of conversion feature																																																															14,400,000	10,900,000	10,900,000
Business Combination, Payment Withheld																																																																				61,800,000	44,900,000
Convertible debt, shares issued upon conversion																12,894,044
Debt Conversion, Converted Instrument, Amount																																																															614,700,000	466,000,000	510,900,000
Long-term debt, principal repayment																																																															600,300,000	455,100,000
Unrealized gain (loss) on derivatives																											(6,500,000)	7,300,000
Proceeds from issuance of long-term debt		0		0		2,195,400,000																																														1,880,700,000
Underwriting fees related to long-term debt																					14,700,000
Discounts to long-term debt																					4,600,000
Debt issuance costs, capitalized																						18,000,000
Business acquisition, pro forma adjustments															39,200,000									13,000,000
Line of credit facility, maximum borrowing capacity	750,000,000							100,000,000	150,000,000								400,000,000																																																					550,000,000	750,000,000	950,000,000							100,000,000
Line of Credit Facility, Fair Value of Amount Outstanding																				137,400,000
Debt Issuance Cost																																																																																1,800,000
Amortization of Financing Costs																																																																																1,300,000
Line of credit facility, term of facility	5 years
Derivative Instruments Not Designated as Hedging Instruments, Gain (Loss), Net		(8,100,000)		(7,700,000)		(32,400,000)
Cash Held in Bank							80,000,000
Cash Held in Bank, Net of Bank Overdrafts							$ 15,400,000

[1] On June 15, 2012, we issued a €500 million convertible note due December 31, 2013, which included a put conversion feature to the Seller. On August 13, 2013, the conversion feature was exercised for an agreed value upon exercise of €510.9 million, consisting of €500 million in principal and €10.9 million for the conversion feature. On September 3, 2013, we paid the seller in cash a total of €466.0 million ($614.7 million) consisting of €455.1 million ($600.3 million) in principal and €10.9 million ($14.4 million) for the conversion feature. Separate from the Seller's notice to put, we made claims with regard to the representations and warranties provided to us upon close of the Acquisition related to local country regulatory matters associated with pre-acquisition periods. As of December 31, 2013, we had withheld €44.9 million ($61.8 million) from the €500 million in principal related to these outstanding claims. During the first half of 2014, we released the €44.9 million ($61.4 million at settlement) withheld to the Seller as a result of the settlement of these claims. We did not incur any interest on amounts withheld. The €500 million convertible note's embedded conversion feature was determined to meet the definition of a derivative required to be bifurcated and separately accounted for at fair value with changes in fair value recorded in earnings. During 2013 and 2012, we recognized a net loss of $6.5 million and a net gain of $7.3 million, respectively, on the conversion feature related to changes in the fair value of the conversion feature. The cash and non-cash interest, excluding the change in fair value of the convertible feature, resulted in an immaterial impact to our effective interest rate for 2013 and 2012. See Note 17, "Derivative Instruments and Hedging Activities" for further discussion.

[2] During the third quarter of 2005, Molson Coors Capital Finance ULC completed a CAD 900 million private placement in Canada due September 22, 2015. Additionally, during the fourth quarter 2010, Molson Coors International LP completed a CAD 500 million private placement in Canada due October 6, 2017. Prior to issuing the bonds, we entered into forward starting interest rate transactions for a portion of each Canadian offering. The bond forward transactions effectively established, in advance, the yield of the government of Canada bond rate over which the Company's private placement was priced. At the time of the private placement offerings and pricings, the government of Canada bond rates were trading at a yield lower than that locked in with the Company's interest rate locks. This resulted in a loss on the bond forward transactions of $4.0 million related to the CAD 900 million bonds, and $7.8 million on the CAD 500 million bonds. Per authoritative accounting guidance pertaining to derivatives and hedging, the losses are being amortized over the life of each respective Canadian issued private placement and will serve to increase our effective cost of borrowing compared to the stated coupon rates by 0.05% and 0.23% on the CAD 900 million and CAD 500 million bonds, respectively.

[3] During the second quarter of 2014, we entered into a five-year, $750 million revolving multi-currency credit facility, which provides a $100 million sub-facility available for the issuance of letters of credit. This revolving facility replaced our existing $400 million and $550 million revolving credit facilities, which had maturities in the second quarters of 2015 and 2016, respectively. As a result, we made a reduction to the size of our existing commercial paper program of $950 million which was approved and implemented during the first quarter of 2013 to a maximum aggregate amount outstanding at any time of $750 million. Concurrent with the transaction, we incurred $1.8 million of issuance costs related to the this revolving credit facility which are being amortized over the term of the agreement and recognized $1.3 million of accelerated amortization related to the termination of the pre-existing facilities. As of December 31, 2014, there were no borrowings under our this revolving credit facility. There were no outstanding borrowings under our pre-existing credit facilities upon termination or as of December 31, 2013. The $750 million revolving credit facility contains customary events of default and specified representations and warranties and covenants, including, among other things, covenants that limit our subsidiaries' ability to incur certain additional priority indebtedness, create or permit liens on assets, or engage in mergers or consolidations.

[4] As of December 31, 2014, we had $64.6 million in bank overdrafts and $80.0 million in bank cash related to our European notional cross-border, cross-currency cash pool for a net positive position of $15.4 million. As of December 31, 2013, we did not have bank overdrafts related to the cash pool.

[5] According to our agreement with the Seller and in accordance with the terms of the senior debt facility agreement, upon the closing of the Acquisition, we immediately repaid pre-existing StarBev third-party debt including accrued interest.

[6] We issued a €500 million Zero Coupon Senior Unsecured Convertible Note due 2013 to the Seller upon close of the Acquisition. See Note 13, "Debt" for further discussion.