Derivative Instruments and Hedging Activities Narrative (Details) In Millions, except Share data, unless otherwise specified		1 Months Ended					9 Months Ended		3 Months Ended				0 Months Ended
	Jun. 30, 2007 USD ($)	Sep. 30, 2011 Cash Flow Hedging [Member] Cross currency swaps USD ($)	Sep. 29, 2012 Cash Flow Hedging [Member] Cross currency swaps USD ($)	Sep. 29, 2012 Cash Flow Hedging [Member] Cross currency swaps GBP (£)	Apr. 10, 2007 Cash Flow Hedging [Member] Cross currency swaps CAD	Apr. 10, 2007 Cash Flow Hedging [Member] Cross currency swaps GBP (£)	Sep. 29, 2012 Forecast USD ($) M	May 03, 2012 Senior Notes [Member] USD ($)	Sep. 29, 2012 Term Loan Facility [Member] years	Apr. 03, 2012 Term Loan Facility [Member] USD ($)	Jun. 15, 2012 Molson Coors Central Europe (MCCE)	Jun. 15, 2012 Fair Value, Inputs, Level 3 [Member] Molson Coors Central Europe (MCCE) Debt, Conversion Feature USD ($)	May 03, 2012 Treasury Lock Loss [Member] Interest Rate Contract USD ($)	Apr. 03, 2012 Tranch 1 [Member] Term Loan Facility [Member] USD ($)	Apr. 03, 2012 Tranch 2 [Member] Term Loan Facility [Member] EUR (€)
Schedule of Trading Securities and Other Trading Assets
Debt instrument, face amount	$ 575							$ 1,900		$ 300				$ 150	€ 120
Business acquisition, pro forma adjustments													39.2
Stock available upon conversion of convertible securities (shares)											12,894,044
Derivative liabilities												15.2
Debt instrument, term									4
Derivative, Notional Amount			774	530	1,200	530
Derivatives Percentage Of Derivatives Settled		25.00%
Swap transaction, principal paid				132
Derivative Liability Outstanding Amount Estinguished		98.7	110.6
Derivative Liability, Fair Value, Net			222.2
Unrealized Gain (Loss) on Interest Rate Cash Flow Hedges, Pretax, Accumulated Other Comprehensive Income (Loss)							$ 8.2
Term for Expected Losses Recorded in Accumulated Other Comprehensive Income							12
Maximum Length of Time Hedged in Cash Flow Hedge							3