Income Tax Net Deferred Tax Assets and Liabilities Components (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Operating Loss Carryforwards [Line Items]
Deferred Income Tax Expense (Benefit)		$ 82.7	$ 927.9	$ (91.6)
Domestic net non-current deferred tax liabilities	$ 925.5	797.9	925.5
Foreign net non-current deferred tax assets	42.0	32.5	42.0
Foreign net non-current deferred tax liabilities	740.8	812.8	740.8
Net non-current deferred tax liabilities	1,624.3	$ 1,578.2	$ 1,624.3
Millercoors [Member]
Operating Loss Carryforwards [Line Items]
Deferred Income Tax Expense (Benefit)	$ 1,100.0