Debt Narrative (Details)						0 Months Ended	3 Months Ended		9 Months Ended		3 Months Ended		9 Months Ended				0 Months Ended				3 Months Ended		6 Months Ended	3 Months Ended			1 Months Ended						3 Months Ended		3 Months Ended						0 Months Ended	3 Months Ended	9 Months Ended				3 Months Ended	9 Months Ended									0 Months Ended		3 Months Ended
	Sep. 29, 2012 USD ($)		Dec. 31, 2011 USD ($)		Jun. 30, 2007 USD ($)	May 03, 2012 Senior Notes [Member] USD ($)	Sep. 29, 2012 Senior Notes [Member] USD ($)	Sep. 24, 2011 Senior Notes [Member] USD ($)	Sep. 29, 2012 Senior Notes [Member] USD ($)	Sep. 24, 2011 Senior Notes [Member] USD ($)	Sep. 29, 2012 Senior Notes [Member] $575 million 2.5% convertible Senior Notes due 2013 USD ($)	Sep. 24, 2011 Senior Notes [Member] $575 million 2.5% convertible Senior Notes due 2013 USD ($)	Sep. 29, 2012 Senior Notes [Member] $575 million 2.5% convertible Senior Notes due 2013 USD ($)	Sep. 24, 2011 Senior Notes [Member] $575 million 2.5% convertible Senior Notes due 2013 USD ($)	Dec. 31, 2011 Senior Notes [Member] $575 million 2.5% convertible Senior Notes due 2013 USD ($)	Jun. 15, 2007 Senior Notes [Member] $575 million 2.5% convertible Senior Notes due 2013 USD ($)	May 03, 2012 Senior Notes [Member] 2.0% Interest Rate, Maturing 2017 [Member] USD ($)	May 03, 2012 Senior Notes [Member] 3.5% Interest Rate, Maturing 2022 [Member] USD ($)	May 03, 2012 Senior Notes [Member] 5.0% Interest Rate, Maturing 2042 [Member] USD ($)	Sep. 22, 2005 Senior Notes [Member] 5.0% Interest Rate, Maturing 2042 [Member]	Sep. 29, 2012 Term Loan Agreement [Member] years	Apr. 03, 2012 Term Loan Agreement [Member] USD ($)	Sep. 29, 2012 Line of Credit [Member] years	Jun. 25, 2011 Line of Credit [Member] Revolving Multicurrency Bank Credit Facility [Member] years	Sep. 29, 2012 Line of Credit [Member] Revolving Multicurrency Bank Credit Facility [Member] USD ($)	Sep. 24, 2011 Line of Credit [Member] Revolving Multicurrency Bank Credit Facility [Member] USD ($)	Sep. 29, 2012 Revolving Credit [Member] USD ($) years	Sep. 10, 2012 Revolving Credit [Member] USD ($)	Sep. 10, 2012 Revolving Credit [Member] EUR (€)	Apr. 03, 2012 Revolving Credit [Member] USD ($)	Sep. 29, 2012 Other Debt Obligations [Member] Notes Payable, Other Payables [Member] USD ($)	Dec. 31, 2011 Other Debt Obligations [Member] Notes Payable, Other Payables [Member] USD ($)	Sep. 29, 2012 Tranch 1 [Member] Term Loan Agreement [Member] USD ($)	Apr. 03, 2012 Tranch 1 [Member] Term Loan Agreement [Member] USD ($)	Sep. 29, 2012 Tranch 2 [Member] Term Loan Agreement [Member] EUR (€)	Apr. 03, 2012 Tranch 2 [Member] Term Loan Agreement [Member] EUR (€)	Jun. 15, 2012 Molson Coors Central Europe (MCCE) USD ($)	Jun. 15, 2012 Molson Coors Central Europe (MCCE) EUR (€)	Jun. 15, 2012 Molson Coors Central Europe (MCCE) Convertible Debt [Member] USD ($)		Jun. 15, 2012 Molson Coors Central Europe (MCCE) Convertible Debt [Member] Zero Coupon Senior Unsecured Note [Member] EUR (€)	Sep. 29, 2012 Molson Coors Central Europe (MCCE) Convertible Debt [Member] Zero Coupon Senior Unsecured Note [Member] USD ($)	Sep. 29, 2012 Molson Coors Central Europe (MCCE) Convertible Debt [Member] Zero Coupon Senior Unsecured Note [Member] USD ($)	Jun. 15, 2012 Molson Coors Central Europe (MCCE) Senior Notes [Member] USD ($)		Jun. 15, 2012 Molson Coors Central Europe (MCCE) Senior Notes [Member] EUR (€)	Sep. 29, 2012 Equity conversion feature of debt Molson Coors Central Europe (MCCE) Convertible Debt [Member] Zero Coupon Senior Unsecured Note [Member] USD ($)	Sep. 29, 2012 Equity conversion feature of debt Molson Coors Central Europe (MCCE) Convertible Debt [Member] Zero Coupon Senior Unsecured Note [Member] USD ($)	Sep. 29, 2012 Fair Value, Inputs, Level 3 [Member] USD ($)	Dec. 31, 2011 Fair Value, Inputs, Level 3 [Member] USD ($)	Sep. 29, 2012 Fair Value, Inputs, Level 3 [Member] Debt [Member] USD ($)	Jun. 15, 2012 Fair Value, Inputs, Level 3 [Member] Debt [Member] Molson Coors Central Europe (MCCE) USD ($)	Sep. 29, 2012 Fair Value, Inputs, Level 1 [Member] USD ($)	Dec. 31, 2011 Fair Value, Inputs, Level 1 [Member] USD ($)	Sep. 29, 2012 Fair Value, Inputs, Level 2 [Member] USD ($)	Dec. 31, 2011 Fair Value, Inputs, Level 2 [Member] USD ($)	May 03, 2012 Bridge Facility Fees [Member] Bridge Loan [Member] USD ($)	May 03, 2012 Treasury Lock Loss [Member] Interest Rate Contract [Member] USD ($)	Sep. 29, 2012 Issuer 2002 [Member] Senior Notes [Member] Senior Notes due 2012 $850 million 6.375% [Member] USD ($) years	May 07, 2002 Issuer 2002 [Member] Senior Notes [Member] Senior Notes due 2012 $850 million 6.375% [Member] USD ($)
Debt Instrument [Line Items]
Repayments of long-term debt																																	$ 150,000,000		€ 26,000,000																								$ 850,000,000
Debt instrument, interest rate percentage											2.50%		2.50%			2.50%	2.00%	3.50%	5.00%	5.00%																						0.00%	0.00%																	6.375%
Debt, principal amount, per share																1,000
Debt, convertible conversion price per share											$ 52.79		$ 52.79			$ 54.76
Percentage of premium over stock price of convertible debt																25.00%
Debt instrument, convertible number of equity instruments, ratio											18.9441		18.9441			18.263
Interest expense, debt amortization							4,500,000	4,400,000	13,500,000	13,100,000
Interest expense, debt											3,600,000	3,600,000	10,800,000
Effective interest rate percentage											5.78%	5.86%	5.79%	5.87%
Convertible debt instrument, carrying amount of equity component											103,900,000		103,900,000
Convertible debt instrument, carrying amount of the equity component, net of tax											64,200,000		64,200,000
Unamortized debt discount											15,400,000		15,400,000		28,900,000																7,100,000	1,900,000
Debt instrument, face amount					575,000,000	1,900,000,000						575,000,000		575,000,000		575,000,000	300,000,000	500,000,000	1,100,000,000			300,000,000							150,000,000	300,000,000				150,000,000		120,000,000					500,000,000																			850,000,000
Noncash interest expense due to amortization of unamortized debt discount in future periods convertible debt estimated range low													4,600,000
Noncash interest expense due to amortization of unamortized debt discount in future periods convertible debt estimated range high													10,800,000
Business acquisition, cost of acquired entity, liabilities incurred																																					3,400,000,000	2,700,000,000	645,900,000	[1]	500,000,000			585,000,000	[2]	500,000,000
Stock available upon conversion of convertible securities (shares)																																					12,894,044	12,894,044
Derivative liabilities																																																				15,200,000
Discounts to long-term debt						4,600,000																																			1,300,000
Long-term debt	4,668,900,000		1,959,600,000																																							642,200,000	642,200,000
Derivative financial instruments, liabilities, fair value disclosure																																															29,000,000	29,000,000	29,000,000	0	29,000,000
Unrealized loss, change in fair value of debt convertion feature																																															8,200,000	13,800,000
Amortization of debt discount (premium)																																										400,000	500,000
Convertible debt instrument, effective interest rate																																										0.25%
Proceeds from issuance of senior long-term debt						1,880,700,000											300,000,000	500,000,000	1,100,000,000
Underwriting fees related to long-term debt						14,700,000
Capitalized debt issuance costs						18,000,000																						400,000		5,100,000
Business acquisition, pro forma adjustments																																																									13,000,000	39,200,000
Debt instrument, term																					4		4	4			1																																10
Long-term debt, quarterly installment payments, percentage of initial principal obligation																						2.50%
Long-term debt, lump sum payment due following installments, percent of principal obligation																						62.50%
Revolving credit facility, maximum borrowing capacity																										400,000,000				550,000,000
Additional capacity for letters of credit																										100,000,000
Credit facility, current borrowing capacity	0	[3]	0	[3]																					0		0
Debt issuance costs capitalized																						3,000,000
Short-term borrowings	27,800,000		2,200,000
Long-term debt, fair value	5,025,900,000		2,133,600,000																																																		2,708,100,000	608,500,000
Debt instrument, fair value disclosure																																																							$ 2,317,200,000	$ 1,525,100,000

[1] 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.

[2] 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.

[3] On September 10, 2012, we entered into a revolving credit agreement ("Euro Credit Agreement") to support the operations of our Central Europe segment. The Euro Credit Agreement provides for a 1-year revolving credit facility of €150 million on an uncommitted basis. On April 3, 2012, we entered into a revolving credit agreement (the ''Credit Agreement''). The Credit Agreement provides for a 4-year revolving credit facility of $300 million that was subsequently amended to increase the borrowing limit to $550 million. The Credit Agreement 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. In the second quarter of 2011, we entered into an agreement for a 4-year revolving multicurrency credit facility of $400 million, which provides a $100 million sub-facility available for the issuance of letters of credit.In relation to the credit facilities issued in the second quarter and third quarter of 2012, we incurred $5.1 million and $0.4 million, of total issuance costs and up-front fees, respectively, which are being amortized over the terms of each respective facility. There were no outstanding borrowings on these credit facilities as of September 29, 2012.