Goodwill and Intangible Assets Intangible Assets (Details) $ in Millions		3 Months Ended			6 Months Ended		12 Months Ended
	Apr. 30, 2015 CAD brewer	Jun. 30, 2015 USD ($)	Sep. 30, 2014 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Mar. 31, 2014 USD ($)
Details of intangible assets, other than goodwill:
Amortization of Intangible Assets		$ 5.9		$ 10.4	$ 13.7	$ 21.0
Restructuring charges		33.7		2.7	42.3	(49.8)
Intangible assets subject to amortization:
Total Gross		5,727.9			5,727.9		$ 6,115.4
Accumulated amortization		(354.6)			(354.6)		(359.6)
Total Net		5,373.3			5,373.3		5,755.8
Brands [Member]
Intangible assets subject to amortization:
Finite-Lived Intangible Assets, Gross		467.9			467.9		483.5
Accumulated amortization		(230.5)			(230.5)		(229.1)
Net		237.4			237.4		254.4
Indefinite-lived intangible assets		4,295.4			$ 4,295.4		$ 4,590.2
Brands [Member] | Minimum [Member]
Intangible assets subject to amortization:
Useful life - minimum (in years)					3 years		3 years
Brands [Member] | Maximum [Member]
Intangible assets subject to amortization:
Useful life - minimum (in years)					40 years		40 years
Distribution Rights [Member]
Intangible assets subject to amortization:
Finite-Lived Intangible Assets, Gross		105.5			$ 105.5		$ 122.0
Accumulated amortization		(94.0)			(94.0)		(101.1)
Net		11.5			$ 11.5		$ 20.9
Distribution Rights [Member] | Minimum [Member]
Intangible assets subject to amortization:
Useful life - minimum (in years)					3 years		3 years
Distribution Rights [Member] | Maximum [Member]
Intangible assets subject to amortization:
Useful life - minimum (in years)					28 years		28 years
Other Intangible Assets [Member]
Intangible assets subject to amortization:
Finite-Lived Intangible Assets, Gross		31.9			$ 31.9		$ 31.7
Accumulated amortization		(30.1)			(30.1)		(29.4)
Net		1.8			1.8		2.3
Indefinite-lived intangible assets		17.5			$ 17.5		$ 17.5
Other Intangible Assets [Member] | Minimum [Member]
Intangible assets subject to amortization:
Useful life - minimum (in years)					2 years		2 years
Other Intangible Assets [Member] | Maximum [Member]
Intangible assets subject to amortization:
Useful life - minimum (in years)					8 years		8 years
Distribution Networks [Member]
Intangible assets subject to amortization:
Indefinite-lived intangible assets		809.7			$ 809.7		$ 870.5
Ontario, Canada [Member] | Subsequent Event [Member]
Details of intangible assets, other than goodwill:
Number of largest brewers | brewer	2
Canada [Member]
Details of intangible assets, other than goodwill:
Percentage Of Fair Value Exceeding Carrying Value							11.00%
Canada [Member] | Licensing Agreements [Member]
Details of intangible assets, other than goodwill:
Amortization of Intangible Assets		$ 0.0		$ 0.0	$ 0.0	$ 4.9
Impairment of Intangible Assets, Finite-lived			$ 8.9
Intangible assets subject to amortization:
Net									$ 4.9
Europe [Member]
Details of intangible assets, other than goodwill:
Percentage Of Fair Value Exceeding Carrying Value							14.00%
Europe [Member] | Brand Impairment [Member]
Details of intangible assets, other than goodwill:
Restructuring charges							$ 360.0	$ 150.9
Brewer's Retail Inc. (BRI) [Member] | Canada [Member] | Subsequent Event [Member]
Details of intangible assets, other than goodwill:
Sales tax, annual charge | CAD	CAD 100,000,000
Sales Tax Agreement, Term	4 years
Long-term commitment to invest | CAD	CAD 100,000,000
Long-term commitment to invest, term	4 years
Enhancement of Purchasing Experience [Member] | Brewer's Retail Inc. (BRI) [Member] | Canada [Member] | Subsequent Event [Member]
Details of intangible assets, other than goodwill:
Long-term commitment to invest (percent)	80.00%