Goodwill and Intangible Assets Amortization Expense (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Sep. 30, 2014 event		Sep. 28, 2013		Sep. 30, 2014		Sep. 28, 2013		Dec. 31, 2013
Estimated amortization expense of finite-lived intangible assets
2014 - remaining	$ 8.7				$ 8.7
2015	28.2				28.2
2016	26.0				26.0
2017	13.4				13.4
2018	11.6				11.6
Amortization expense of intangible assets	10.1		12.1		31.1		35.7
Indefinite-lived Intangible Assets, Impairment Losses	0
Goodwill	2,294.1				2,294.1				2,418.7
Number of events triggering potential impairment	0
Licensing Agreements [Member]
Estimated amortization expense of finite-lived intangible assets
Finite-Lived Intangible Assets, Net	18.8				18.8
Canada [Member]
Estimated amortization expense of finite-lived intangible assets
Percentage Of Fair Value Exceeding Carrying Value	14.00%				14.00%
Goodwill	681.3				681.3				718.2
Canada [Member] | Licensing Agreements [Member]
Estimated amortization expense of finite-lived intangible assets
Amortization expense of intangible assets	8.9	[1]	0	[1]	13.8	[1]	0	[1]
Finite-Lived Intangible Assets, Net									4.9
Brands [Member]
Estimated amortization expense of finite-lived intangible assets
Indefinite-lived intangible assets	4,797.6				4,797.6				5,482.3
Molson Core Brands [Member]
Estimated amortization expense of finite-lived intangible assets
Percentage Of Fair Value Exceeding Carrying Value	11.00%				11.00%
Indefinite-lived intangible assets	2,711.1				2,711.1
Jelen Ozujsko Branik [Member] [Member]
Estimated amortization expense of finite-lived intangible assets
Indefinite-lived intangible assets	$ 867.9				$ 867.9

[1] During the third quarter of 2014, we recognized an impairment charge related to our definite-lived intangible asset associated with our license agreement with Miller in Canada. See Note 15, "Commitments and Contingencies" for further discussion. Additionally, upon termination of our MMI operations in the first quarter of 2014, we recognized charges associated with the write-off of the definite-lived intangible asset associated with the joint venture. See Note 4, "Investments" for further discussion.