Special Items Severance and Other Employee Related (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2018 USD ($) employee	Sep. 30, 2018 USD ($) employee	Sep. 30, 2017 USD ($)
Severance and other employee-related costs [Member]
Changes in restructuring accruals [Roll Forward]
Beginning balance of restructuring accruals		$ 6.9	$ 14.7
Charges incurred and changes in estimates		33.6	2.1
Payments made		(6.4)	(9.2)
Foreign currency and other adjustments		(0.2)	0.6
Ending balance of restructuring accruals	$ 33.9	33.9	8.2
Severance and other employee-related costs [Member] | UNITED STATES
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | employee	350
Changes in restructuring accruals [Roll Forward]
Beginning balance of restructuring accruals		0.6	5.1
Charges incurred and changes in estimates		30.3	0.7
Payments made		(1.2)	(5.1)
Foreign currency and other adjustments		0.0	0.0
Ending balance of restructuring accruals	$ 29.7	29.7	0.7
Severance and other employee-related costs [Member] | Canada [Member]
Changes in restructuring accruals [Roll Forward]
Beginning balance of restructuring accruals		4.3	5.9
Charges incurred and changes in estimates		(0.8)	(0.3)
Payments made		(1.8)	(1.4)
Foreign currency and other adjustments		(0.1)	0.4
Ending balance of restructuring accruals	1.6	1.6	4.6
Severance and other employee-related costs [Member] | Europe [Member]
Changes in restructuring accruals [Roll Forward]
Beginning balance of restructuring accruals		1.8	2.8
Charges incurred and changes in estimates		2.2	0.1
Payments made		(2.6)	(1.2)
Foreign currency and other adjustments		(0.1)	0.2
Ending balance of restructuring accruals	1.3	1.3	1.9
Severance and other employee-related costs [Member] | International [Member]
Changes in restructuring accruals [Roll Forward]
Beginning balance of restructuring accruals		0.2	0.2
Charges incurred and changes in estimates		1.9	1.5
Payments made		(0.8)	(0.8)
Foreign currency and other adjustments		0.0	0.0
Ending balance of restructuring accruals	1.3	1.3	0.9
Severance and other employee-related costs [Member] | Corporate [Member]
Changes in restructuring accruals [Roll Forward]
Beginning balance of restructuring accruals		0.0	0.7
Charges incurred and changes in estimates		0.0	0.1
Payments made		0.0	(0.7)
Foreign currency and other adjustments		0.0	0.0
Ending balance of restructuring accruals	$ 0.0	$ 0.0	$ 0.1
Facility Closing [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | employee		456
Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Payment of severance obligations, term		12 months
MillerCoors
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Number of Positions Eliminated | employee		110