Special Items Restructuring Accruals (Details) $ in Millions	12 Months Ended
	Dec. 31, 2017 USD ($) employee	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($) employee
Restructuring Cost and Reserve [Line Items]
Special items, net	$ 28.1	$ (2,522.4)	$ 346.7
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance	14.7	9.2	15.5
Balance assumed in Acquisition		6.9
Charges incurred	2.6	9.4	9.5
Payments made	(10.9)	(8.0)	(13.7)
Restructuring Reserve, Accrual Adjustment		(2.1)	(1.2)
Foreign currency and other adjustments	0.5	(0.7)	(0.9)
Restructuring accruals, ending balance	6.9	14.7	9.2
U.S.
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance	5.1	0.0	0.0
Balance assumed in Acquisition		6.9
Charges incurred	0.8	3.2	0.0
Payments made	(5.3)	(5.0)	0.0
Restructuring Reserve, Accrual Adjustment		0.0	0.0
Foreign currency and other adjustments	0.0	0.0	0.0
Restructuring accruals, ending balance	0.6	5.1	0.0
International
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance	0.2	1.3	0.0
Balance assumed in Acquisition		0.0
Charges incurred	1.6	0.3	3.2
Payments made	(1.6)	(1.4)	(1.9)
Restructuring Reserve, Accrual Adjustment		0.0	0.0
Foreign currency and other adjustments	0.0	0.0	0.0
Restructuring accruals, ending balance	0.2	0.2	1.3
Corporate
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance	0.7	0.0	0.2
Balance assumed in Acquisition		0.0
Charges incurred	0.1	0.7	0.0
Payments made	(0.8)	0.0	(0.2)
Restructuring Reserve, Accrual Adjustment		0.0	0.0
Foreign currency and other adjustments	0.0	0.0	0.0
Restructuring accruals, ending balance	0.0	0.7	0.0
Canada
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance	5.9	2.3	3.8
Balance assumed in Acquisition		0.0
Charges incurred	0.0	4.0	2.1
Payments made	(1.9)	(0.4)	(3.1)
Restructuring Reserve, Accrual Adjustment		0.0	0.0
Foreign currency and other adjustments	0.3	0.0	(0.5)
Restructuring accruals, ending balance	4.3	5.9	2.3
Europe [Member]
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance	2.8	5.6	11.5
Balance assumed in Acquisition		0.0
Charges incurred	0.1	1.2	4.2
Payments made	(1.3)	(1.2)	(8.5)
Restructuring Reserve, Accrual Adjustment		(2.1)	(1.2)
Foreign currency and other adjustments	0.2	(0.7)	(0.4)
Restructuring accruals, ending balance	$ 1.8	2.8	$ 5.6
CHINA
Restructuring Reserve [Roll Forward]
Number of positions eliminated | employee			125
Maximum
Restructuring Reserve [Roll Forward]
Payment of Severance Obligations, Term	12 months
Millercoors [Member]
Restructuring Reserve [Roll Forward]
Charges incurred	$ 1.6	$ 9.3
Number of positions eliminated | employee	93