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Segment Reporting - Income (Loss) Before Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2020	Sep. 30, 2019
Segment Reporting Information [Line Items]
Income (loss) before income taxes	$ 450.4	$ (308.6)			$ 693.4	$ 273.3
Other income (expense), net	2.4	(13.7)			3.4	(0.7)
Montreal brewery
Segment Reporting Information [Line Items]
Proceeds from sale of Montreal brewery			$ 96.2
Gain on sale of Montreal brewery			$ 61.3
Unallocated
Segment Reporting Information [Line Items]
Income (loss) before income taxes	8.7	(74.1)			(148.2)	(191.6)
Unrealized gain (loss) on commodity contracts	64.4	(14.9)			24.7	(12.0)
North America \| Operating Segments
Segment Reporting Information [Line Items]
Income (loss) before income taxes	400.8	(287.4)			888.5	407.0
Europe \| Operating Segments
Segment Reporting Information [Line Items]
Income (loss) before income taxes	$ 40.9	$ 52.9			$ (46.9)	$ 57.9
Acquisition purchase price adjustment settlement gain \| Affiliated entity
Segment Reporting Information [Line Items]
Other income (expense), net				$ 1.5