Goodwill and Intangible Assets Intangible Assets (Details) (USD $)	12 Months Ended							3 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 29, 2012		Dec. 31, 2013	Mar. 31, 2014	Dec. 31, 2013	Jun. 15, 2012	Sep. 30, 2014
Intangible assets subject to amortization:
Accumulated amortization	$ (359,600,000)		$ (513,700,000)				(513,700,000)		$ (513,700,000)
Intangible assets not subject to amortization:
Total Gross	6,115,400,000		7,338,800,000				7,338,800,000		7,338,800,000
Total Net	5,755,800,000		6,825,100,000				6,825,100,000		6,825,100,000
Total special items	324,400,000		200,000,000		81,400,000
Goodwill	2,191,600,000		2,418,700,000		2,453,100,000		2,418,700,000		2,418,700,000
Loss on goodwill impairment	0		0
Brands
Intangible assets subject to amortization:
Gross	483,500,000		537,500,000				537,500,000		537,500,000
Accumulated amortization	(229,100,000)		(224,700,000)				(224,700,000)		(224,700,000)
Net	254,400,000		312,800,000				312,800,000		312,800,000
Intangible assets not subject to amortization:
Indefinite-lived intangibles	4,590,200,000		5,482,300,000				5,482,300,000		5,482,300,000
Useful life	30 years
Indefinite-lived intangible assets, fair value										2,323,400,000
Percentage of fair value exceeding carrying value	9.00%
Brands | Minimum
Intangible assets not subject to amortization:
Useful life	3 years						3 years
Brands | Maximum
Intangible assets not subject to amortization:
Useful life	40 years						40 years
License agreements and distribution rights
Intangible assets subject to amortization:
Gross	122,000,000		314,100,000				314,100,000		314,100,000
Accumulated amortization	(101,100,000)		(255,000,000)				(255,000,000)		(255,000,000)
Net	20,900,000		59,100,000				59,100,000		59,100,000
License agreements and distribution rights | Minimum
Intangible assets not subject to amortization:
Useful life	3 years						2 years
License agreements and distribution rights | Maximum
Intangible assets not subject to amortization:
Useful life	28 years						23 years
Distribution networks
Intangible assets not subject to amortization:
Indefinite-lived intangibles	870,500,000		952,300,000				952,300,000		952,300,000
Other
Intangible assets subject to amortization:
Gross	31,700,000		37,400,000				37,400,000		37,400,000
Accumulated amortization	(29,400,000)		(34,000,000)				(34,000,000)		(34,000,000)
Net	2,300,000		3,400,000				3,400,000		3,400,000
Intangible assets not subject to amortization:
Indefinite-lived intangibles	17,500,000		15,200,000				15,200,000		15,200,000
Other | Minimum
Intangible assets not subject to amortization:
Useful life	2 years						2 years
Other | Maximum
Intangible assets not subject to amortization:
Useful life	8 years						42 years
Jelen Ozujsko Branik
Intangible assets not subject to amortization:
Indefinite-lived intangibles	817,200,000
Molson Core Brand
Intangible assets not subject to amortization:
Indefinite-lived intangibles	2,612,400,000
Europe
Intangible assets not subject to amortization:
Percentage of fair value exceeding carrying value	14.00%
Goodwill	1,528,000,000		1,693,200,000		1,680,900,000		1,693,200,000		1,693,200,000
Canada
Intangible assets not subject to amortization:
Percentage of fair value exceeding carrying value	11.00%
Goodwill	656,500,000		718,200,000		764,000,000		718,200,000		718,200,000
Modelo
Details of intangible assets, other than goodwill:
Amortization of the difference between MCBC contributed cost basis and proportionate share of the underlying equity in net assets of MillerCoors								4,900,000
Intangible assets not subject to amortization:
Loss on impairment of finite-lived intangible assets								40,500,000
License Agreement
Intangible assets subject to amortization:
Net	9,000,000										18,800,000
License Agreement | Canada
Intangible assets not subject to amortization:
Loss on impairment of finite-lived intangible assets	8,900,000								17,900,000
Software abandonment | Canada
Intangible assets not subject to amortization:
Total special items	13,800,000	[1]	17,900,000	[1]	0	[1]
Brand Impairment | Europe
Intangible assets not subject to amortization:
Total special items	$ 360,000,000	[2]	$ 150,900,000	[2]	$ 0	[2]

[1] Upon termination of our MMI operations in 2014, we recognized termination fee income and charges associated with the write-off of the definite-lived intangible asset associated with the joint venture. See Note 5, "Investments" for further discussion.Additionally, in the third quarter of 2014 and fourth quarter of 2013, we recognized impairment charges related to our definite-lived intangible asset associated with our license agreement with Miller in Canada. See Note 12, "Goodwill and Intangible Assets" and Note 19, "Commitments and Contingencies" for further discussion.

[2] During the third quarters of 2014 and 2013, we recognized impairment charges related to indefinite-lived intangible assets in Europe. See Note 12, "Goodwill and Intangible Assets" for further discussion.