Investments MCBC proportional share in MillerCoors (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014		Dec. 31, 2013	Dec. 29, 2012	Dec. 31, 2013		Dec. 31, 2012
Schedule of Equity Method Investments [Line Items]
MillerCoors owners' equity	$ 7,863.3		$ 8,605.2		$ 8,605.2
Investment in MillerCoors	2,388.6		2,506.5		2,506.5
Equity income in MillerCoors	561.8		539.0	510.9
Restructuring charges	14.2		26.8	34.9
MillerCoors
Schedule of Equity Method Investments [Line Items]
MillerCoors owners' equity	7,179.1		7,470.7		7,470.7
Net income attributable to MillerCoors	1,326.2	[1]			1,270.5	[1]	1,190.9	[1]
MCBC economic Interest (as a percent)	42.00%		42.00%		42.00%		42.00%
Investment in MillerCoors	2,388.6		2,506.5		2,506.5
MCBC proportionate share of MillerCoors net income	557.0				533.6		500.2
Amortization of the difference between MCBC contributed cost basis and proportionate share of the underlying equity in net assets of MillerCoors	4.6				4.6		4.9
Share-based compensation adjustment	0.2	[2]			0.8	[2]	5.8	[2]
Equity income in MillerCoors	561.8				539.0		510.9
Restructuring charges	1.4				17.2
Asset write-offs					2.6
Impairment of finite-lived intangible assets							31.8
Molson Coors Brewing Company (MCBC)
Schedule of Equity Method Investments [Line Items]
MillerCoors owners' equity	7,863.3		8,605.2		8,605.2
MCBC economic Interest (as a percent)	42.00%		42.00%		42.00%
MCBC proportionate share in MillerCoors' equity	3,015.2		3,137.7		3,137.7
Difference between MCBC contributed cost basis and proportional share of the underlying equity in net assets of MillerCoors	(661.6)		(666.2)		(666.2)
Accounting policy elections	35.0		35.0		35.0
Investment in MillerCoors	0		0		0
Equity income in MillerCoors	$ 0		$ 0	$ 0

[1] Results for 2014 include special charges related to restructuring activities of $1.4 million. Results for 2013 include special charges related to restructuring activities and asset write-offs of $17.2 million and $2.6 million, respectively. Results for 2012 include special charges of $31.8 million primarily due to the write-down of assets related to discontinuing the production of the Home Draft package in the U.S. and the write-down of information systems assets related to a business transformation project.

[2] The net adjustment is to eliminate all share-based compensation impacts related to pre-existing SABMiller plc equity awards held by former Miller employees employed by MillerCoors.