Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		3 Months Ended	12 Months Ended
	Oct. 11, 2016	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Oct. 10, 2016
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance			$ (1,571.8)
Reclassification of historical share of MillerCoors AOCI loss to income(1)			0.0	$ 258.2	$ 0.0
Balance		$ (1,571.8)	(860.0)	(1,571.8)
Income tax benefit (expense)			(53.2)	$ 1,055.2	$ 61.5
Millercoors [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
MCBC economic Interest (as a percent)	100.00%	42.00%		42.00%	42.00%	42.00%
Millercoors [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
MCBC economic Interest (as a percent)	42.00%
Income tax benefit (expense)	$ 200.1
Accumulated Net Gain (Loss) from Reclassification of Historical Shares Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income | Millercoors [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of historical share of MillerCoors AOCI loss to income(1)			0.0	$ 458.3	$ 0.0
Income tax benefit (expense)			0.0	200.1	0.0
Accumulated Net Gain (Loss) from Reclassification of Historical Shares Attributable to Parent [Member] | Reclassification out of Accumulated Other Comprehensive Income | Millercoors [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of historical share of MillerCoors AOCI loss to income(1)		$ (458.3)
Foreign currency translation adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance			(994.1)	(769.9)	129.8
Foreign currency translation adjustments			638.3	(227.4)	(830.4)
Unrealized gain (loss) on derivative and non-derivative instruments			0.0	0.0	0.0
Reclassification of derivative (gain) loss to income			0.0	0.0	0.0
Pension and other postretirement benefit adjustments			0.0	0.0	0.0
Amortization of net prior service (benefit) cost and net actuarial (gain) loss to income			0.0	0.0	0.0
Reclassification of historical share of MillerCoors AOCI loss to income(1)				0.0
Ownership share of unconsolidated subsidiaries' other comprehensive income (loss)			0.0	0.0	0.0
Tax benefit (expense)			41.2	3.2	(69.3)
Balance		(994.1)	(314.6)	(994.1)	(769.9)
Gain (loss) on derivative instruments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance			21.2	14.5	15.0
Foreign currency translation adjustments			0.0	0.0	(16.0)
Unrealized gain (loss) on derivative and non-derivative instruments			(205.3)	20.0	23.0
Reclassification of derivative (gain) loss to income			2.0	(3.4)	(7.1)
Pension and other postretirement benefit adjustments			0.0	0.0	0.0
Amortization of net prior service (benefit) cost and net actuarial (gain) loss to income			0.0	0.0	0.0
Reclassification of historical share of MillerCoors AOCI loss to income(1)				0.0
Ownership share of unconsolidated subsidiaries' other comprehensive income (loss)			0.0	0.0	0.0
Tax benefit (expense)			71.2	(9.9)	(0.4)
Balance		21.2	(110.9)	21.2	14.5
Gain (loss) on derivative instruments | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Income tax benefit (expense)			0.7	(0.4)	(1.7)
Pension and Postretirement Benefit adjustments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance			(529.0)	(598.3)	(632.0)
Foreign currency translation adjustments			4.7	(7.3)	(1.7)
Unrealized gain (loss) on derivative and non-derivative instruments			0.0	0.0	0.0
Reclassification of derivative (gain) loss to income			0.0	0.0	0.0
Pension and other postretirement benefit adjustments			181.8	64.4	22.8
Amortization of net prior service (benefit) cost and net actuarial (gain) loss to income			4.4	28.9	20.7
Reclassification of historical share of MillerCoors AOCI loss to income(1)				0.0
Ownership share of unconsolidated subsidiaries' other comprehensive income (loss)			0.0	0.0	0.0
Tax benefit (expense)			(36.9)	(16.7)	(8.1)
Balance		(529.0)	(375.0)	(529.0)	(598.3)
Pension and Postretirement Benefit adjustments | Reclassification out of Accumulated Other Comprehensive Income
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Income tax benefit (expense)			0.8	6.1	4.6
Equity Method Investments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Reclassification of historical share of MillerCoors AOCI loss to income(1)				458.3
Accumulated other comprehensive income (loss)
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance			(1,571.8)	(1,704.1)	(871.9)
Foreign currency translation adjustments			643.0	(234.7)	(848.1)
Unrealized gain (loss) on derivative and non-derivative instruments			(205.3)	20.0	23.0
Reclassification of derivative (gain) loss to income			2.0	(3.4)	(7.1)
Pension and other postretirement benefit adjustments			181.8	64.4	22.8
Amortization of net prior service (benefit) cost and net actuarial (gain) loss to income			4.4	28.9	20.7
Reclassification of historical share of MillerCoors AOCI loss to income(1)				458.3
Ownership share of unconsolidated subsidiaries' other comprehensive income (loss)			14.3	36.8	56.5
Tax benefit (expense)			71.6	(238.0)	(100.0)
Balance		(1,571.8)	(860.0)	(1,571.8)	(1,704.1)
Equity Method Investments
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Balance			(69.9)	(350.4)	(384.7)
Foreign currency translation adjustments			0.0	0.0	0.0
Unrealized gain (loss) on derivative and non-derivative instruments			0.0	0.0	0.0
Reclassification of derivative (gain) loss to income			0.0	0.0	0.0
Pension and other postretirement benefit adjustments			0.0	0.0	0.0
Amortization of net prior service (benefit) cost and net actuarial (gain) loss to income			0.0	0.0	0.0
Ownership share of unconsolidated subsidiaries' other comprehensive income (loss)			14.3	36.8	56.5
Tax benefit (expense)			(3.9)	(214.6)	(22.2)
Balance		$ (69.9)	$ (59.5)	$ (69.9)	$ (350.4)