Acquisition and Investments Allocation of Consideration Transferred (Details) - USD ($) $ in Millions		1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Oct. 11, 2016	Oct. 31, 2016	Dec. 31, 2016	Oct. 10, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Business Acquisition [Line Items]
Goodwill	$ 6,415.6		$ 8,250.1		$ 8,405.5	$ 8,250.1	$ 1,983.3
Goodwill, Acquired During Period					$ 13.8	$ 6,415.0
Business Combination, Period After Completion With Increased COGS Resulting from Step-Up of Inventory			1 month
SAB Miller [Member]
Business Acquisition [Line Items]
MCBC economic Interest (as a percent)	58.00%		58.00%			58.00%
Millercoors [Member]
Business Acquisition [Line Items]
Defined Benefit Plan, Recognized Net Gain (Loss) Due to Settlements and Curtailments				$ 25.7
MCBC economic Interest (as a percent)	100.00%		42.00%	42.00%		42.00%	42.00%
Millercoors [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Deferred Tax Assets Noncurrent	$ 430.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Land	156.8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Buildings	413.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Equipment	1,927.7
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Software	152.4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Returnable Containers	89.8
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Construction in Progress	259.2
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment	2,998.9
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Intangible Assets, Other than Goodwill	9,875.0
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Inventory	505.4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets	1,061.8
Payments to Acquire Businesses, Gross	$ 12,000.0
MCBC economic Interest (as a percent)	42.00%
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Other Assets	$ 462.3
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Liabilities	(1,190.1)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Pension and Postretirement Benefits	(1,009.7)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Noncurrent Liabilities, Other	(208.3)
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Net	11,989.9
Goodwill	6,323.5
Business Combination, Acquisition of Less than 100 Percent, Noncontrolling Interest, Fair Value	(185.0)
Business Combination, Recognized Identifiable Assets Acquired, Goodwill, and Liabilities Assumed, Less Noncontrolling Interest	18,128.4
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Trade Receivables	344.3
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Current Assets, Receivables	40.2
Cash Acquired from Acquisition		$ 39.0
Business Combination, Step Acquisition, Step-up in Fair Value of Inventory	82.0
Brands | Millercoors [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Indefinite-Lived Intangible Assets	7,320.0
Other Intangible Assets [Member] | Millercoors [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Indefinite-Lived Intangible Assets	320.0
Other Intangible Assets [Member] | Millercoors [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 205.0
Other Intangible Assets [Member] | Minimum | Millercoors [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	2 years
Other Intangible Assets [Member] | Maximum | Millercoors [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	40 years
Brands | Millercoors [Member]
Business Acquisition [Line Items]
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Finite-Lived Intangibles	$ 2,030.0
Brands | Minimum | Millercoors [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	10 years
Brands | Maximum | Millercoors [Member]
Business Acquisition [Line Items]
Acquired Finite-lived Intangible Assets, Weighted Average Useful Life	30 years
Buildings and improvements | Minimum
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life					20 years
Buildings and improvements | Minimum | Millercoors [Member]
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Buildings and improvements | Maximum
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life					40 years
Buildings and improvements | Maximum | Millercoors [Member]
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life	40 years
Returnable containers | Minimum
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life					2 years
Returnable containers | Minimum | Millercoors [Member]
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Returnable containers | Maximum
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life					15 years
Returnable containers | Maximum | Millercoors [Member]
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life	15 years
Machinery and equipment | Minimum
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life					3 years
Machinery and equipment | Minimum | Millercoors [Member]
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life	3 years
Machinery and equipment | Maximum
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life					25 years
Machinery and equipment | Maximum | Millercoors [Member]
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life	25 years
Software and Software Development Costs [Member] | Minimum | Millercoors [Member]
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life	1 year
Software and Software Development Costs [Member] | Maximum | Millercoors [Member]
Business Acquisition [Line Items]
Property, Plant and Equipment, Useful Life	5 years