Special items Summary Special Items (Details) (USD $)	3 Months Ended				6 Months Ended				12 Months Ended
	Jun. 30, 2012		Jun. 25, 2011		Jun. 30, 2012		Jun. 25, 2011		Dec. 26, 2009
Restructuring Cost and Reserve [Line Items]
Total special items	$ 21,200,000		$ 11,000,000		$ 22,700,000		$ 11,000,000
Non-income-related Tax Reserves									10,400,000
Gain (Loss) Related to Restructuring Reserve Low End of Range	0
Gain (Loss) Related to Restructuring Reserve High End of Range	22,300,000
Canada | Restructuring, exit and other related costs associated with the Edmonton and Montreal breweries
Restructuring Cost and Reserve [Line Items]
Total special items	0		600,000		1,600,000		600,000
Canada | Special termination benefits
Restructuring Cost and Reserve [Line Items]
Total special items	1,400,000	[1]	1,200,000	[1]	1,900,000	[1]	4,000,000	[1]
Canada | Flood insurance reimbursement
Restructuring Cost and Reserve [Line Items]
Total special items	(2,300,000)	[2]	700,000	[2]	(2,300,000)	[2]	100,000	[2]
Canada | BRI loan guarantee adjustment
Restructuring Cost and Reserve [Line Items]
Total special items	0	[3]	(2,000,000)	[3]	0	[3]	(2,000,000)	[3]
Canada | Fixed asset adjustment
Restructuring Cost and Reserve [Line Items]
Total special items	0	[4]	7,600,000	[4]	0	[4]	7,600,000	[4]
U.K. | Restructuring charge
Restructuring Cost and Reserve [Line Items]
Total special items	4,500,000		2,400,000		6,300,000		2,700,000
U.K. | Asset abandonment
Restructuring Cost and Reserve [Line Items]
Total special items	7,200,000	[5]	0	[5]	7,200,000	[5]	0	[5]
U.K. | Release of non-income-related tax reserve
Restructuring Cost and Reserve [Line Items]
Total special items	0	[6]	0	[6]	(3,500,000)	[6]	(2,500,000)	[6]
Corporate | Restructuring charge
Restructuring Cost and Reserve [Line Items]
Total special items	0		0		1,100,000		0
MCI | China impairment
Restructuring Cost and Reserve [Line Items]
Total special items	10,400,000	[7]	0	[7]	10,400,000	[7]	0	[7]
MCI | Costs associated with outsourcing and other strategic initiatives
Restructuring Cost and Reserve [Line Items]
Total special items	$ 0		$ 500,000		$ 0		$ 500,000

[1] During the second quarters and first halves of 2012 and 2011, we recognized charges related to special termination benefits as eligible employees elected early retirement offered as a result of the ratification of Collective Bargaining Agreements with MCC's brewery groups in 2011 and 2012.

[2] In the second quarter and first half of 2012, we received insurance proceeds in excess of expenses incurred related to the flood damages at our Toronto offices. During the second quarter and first half of 2011, we incurred expenses related to these damages, which were partially offset by insurance proceeds.

[3] During the second quarter of 2011, we recognized a gain resulting from a reduction of our guarantee of BRI debt obligations, which is discussed further in Note 16 "Commitments and Contingencies."

[4] During the second quarter of 2011, we recognized a loss related to the correction of an immaterial error in prior periods to reduce Properties in the Canada segment, resulting from the performance of a fixed asset count. The impact of the error and the related correction in 2011 is not material to any prior annual or interim financial statements and is not material to the fiscal year results for 2011.

[5] During the second quarter of 2012, we recognized an asset abandonment charge related to the discontinuation of primary packaging in the U.K. We determined that our Home Draft package was not meeting expectations driven by a lack of demand in the U.K. market and as a result, we recognized a loss related to the write-off of the Home Draft packaging line, tooling equipment and packaging materials inventory.

[6] During 2009, we established a non-income-related tax reserve of $10.4 million that was recorded as a Special item. Our estimates indicated a range of possible loss relative to this reserve of zero to $22.3 million, inclusive of potential penalties and interest. The amounts recorded in 2012 and 2011 represent a release of a portion of this reserve as a result of a change in estimate.

[7] See related detail in Note 12 "Goodwill and Intangible Assets."