CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Sales Revenue, Goods, Gross									$ 13,471.5	$ 6,597.4	$ 5,127.4
Sales	$ 3,211.7	$ 3,552.9	$ 3,793.1	$ 2,913.8	$ 2,901.9	$ 1,337.7	$ 1,407.0	$ 950.8	11,002.8	4,885.0	3,567.5
Excise taxes	(632.1)	(669.7)	(701.8)	(465.1)	(607.9)	(390.1)	(420.8)	(293.6)	(2,468.7)	(1,712.4)	(1,559.9)
Net sales	2,579.6	2,883.2	3,091.3	2,448.7	2,294.0	947.6	986.2	657.2	11,002.8	4,885.0	3,567.5
Cost of goods sold	(1,514.7)	(1,584.1)	(1,750.7)	(1,367.7)	(1,481.9)	(537.4)	(558.1)	(410.1)	(6,217.2)	(2,987.5)	(2,131.6)
Gross profit	1,064.9	1,299.1	1,340.6	1,081.0	812.1	410.2	428.1	247.1	4,785.6	1,897.5	1,435.9
Marketing, general and administrative expenses									(3,032.4)	(1,589.8)	(1,038.3)
Special items, net									(28.1)	2,522.4	(346.7)
Equity Income Loss in Equity Method Investment									0.0	500.9	516.3
Operating income (loss)									1,725.1	3,331.0	567.2
Other income (expense), net
Interest expense									(349.3)	(271.6)	(120.3)
Interest income									6.0	27.2	8.3
Other income (expense), net									(0.1)	(29.7)	0.9
Total other income (expense), net									(343.4)	(274.1)	(111.1)
Income (loss) from continuing operations before income taxes									1,381.7	3,056.9	456.1
Income tax benefit (expense)									53.2	(1,055.2)	(61.5)
Net income (loss) from continuing operations									1,434.9	2,001.7	394.6
Income (loss) from discontinued operations, net of tax	0.7	(0.2)	1.6	(0.6)	(0.5)	0.0	(1.8)	(0.5)	1.5	(2.8)	3.9
Net income (loss) including noncontrolling interests									1,436.4	1,998.9	398.5
Net (income) loss attributable to noncontrolling interests									(22.2)	(5.9)	(3.3)
Net income (loss) attributable to Molson Coors Brewing Company	$ 588.8	$ 287.0	$ 329.9	$ 208.5	$ 1,439.3	$ 207.7	$ 177.9	$ 168.1	$ 1,414.2	$ 1,993.0	$ 395.2
Basic net income (loss) attributable to Molson Coors Brewing Company per share:
Basic net income (loss) from continuing operations attributable to MCBC per share	$ 2.73	$ 1.33	$ 1.52	$ 0.97	$ 6.70	$ 0.97	$ 0.84	$ 0.83	$ 6.56	$ 9.41	$ 2.11
From discontinued operations (in dollars per share)	0.00	0.00	0.01	0.00	0.00	0.00	(0.01)	0.00	0.01	(0.01)	0.02
Basic net income (loss) attributable to Molson Coors Brewing Company (in dollars per share)	2.73	1.33	1.53	0.97	6.70	0.97	0.83	0.83	6.57	9.40	2.13
Diluted net income (loss) attributable to Molson Coors Brewing Company per share:
From continuing operations (in dollars per share)	2.72	1.33	1.52	0.97	6.65	0.96	0.83	0.82	6.52	9.35	2.10
From discontinued operations (in dollars per share)	0.00	0.00	0.00	(0.01)	0.00	0.00	(0.01)	0.00	0.01	(0.01)	0.02
Diluted net income (loss) attributable to Molson Coors Brewing Company per share	$ 2.72	$ 1.33	$ 1.52	$ 0.96	$ 6.65	$ 0.96	$ 0.82	$ 0.82	$ 6.53	$ 9.34	$ 2.12
Weighted-average shares—basic									215.4	212.0	185.3
Weighted-average shares for diluted EPS									216.5	213.4	186.4
Amounts attributable to Molson Coors Brewing Company
Net income (loss) from continuing operations	$ 588.1	$ 287.2	$ 328.3	$ 209.1	$ 1,439.8	$ 207.7	$ 179.7	$ 168.6	$ 1,412.7	$ 1,995.8	$ 391.3
Income (loss) from discontinued operations, net of tax	0.7	(0.2)	1.6	(0.6)	(0.5)	0.0	(1.8)	(0.5)	1.5	(2.8)	3.9
Net income (loss) attributable to Molson Coors Brewing Company	$ 588.8	$ 287.0	$ 329.9	$ 208.5	$ 1,439.3	$ 207.7	$ 177.9	$ 168.1	1,414.2	1,993.0	395.2
Eliminations
Sales Revenue, Goods, Gross									(521.9)	(216.2)	(112.5)
Sales									(521.9)	(216.2)	(112.5)
Excise taxes									0.0	0.0	0.0
Cost of goods sold									487.0	185.6	80.2
Gross profit									(34.9)	(30.6)	(32.3)
Marketing, general and administrative expenses									34.9	30.6	32.3
Special items, net									0.0	0.0	0.0
Equity Income Loss in Equity Method Investment										0.0	0.0
Operating income (loss)									(1,758.1)	(1,809.3)	(281.6)
Other income (expense), net
Other income (expense), net									0.0	0.0	0.0
Income tax benefit (expense)									0.0	0.0	0.0
Net income (loss) from continuing operations									(1,758.1)	(1,809.3)	(281.6)
Income (loss) from discontinued operations, net of tax									0.0	0.0	0.0
Net income (loss) including noncontrolling interests									(1,758.1)	(1,809.3)	(281.6)
Net (income) loss attributable to noncontrolling interests									0.0	0.0	0.0
Net income (loss) attributable to Molson Coors Brewing Company									(1,758.1)	(1,809.3)	(281.6)
Amounts attributable to Molson Coors Brewing Company
Income (loss) from discontinued operations, net of tax									0.0	0.0	0.0
Net income (loss) attributable to Molson Coors Brewing Company									(1,758.1)	(1,809.3)	(281.6)
Parent Issuer
Sales Revenue, Goods, Gross									21.8	26.5	28.2
Sales									21.8	26.5	28.2
Excise taxes									0.0	0.0	0.0
Cost of goods sold									(2.0)	0.0	0.0
Gross profit									19.8	26.5	28.2
Marketing, general and administrative expenses									(284.8)	(249.6)	(131.0)
Special items, net									(0.8)	(1.0)	0.0
Equity Income Loss in Equity Method Investment										0.0	0.0
Operating income (loss)									1,584.6	2,044.7	365.7
Other income (expense), net
Other income (expense), net									(8.5)	(62.0)	(7.4)
Income tax benefit (expense)									146.5	212.4	104.4
Net income (loss) from continuing operations									1,414.2	1,993.0	395.2
Income (loss) from discontinued operations, net of tax									0.0	0.0	0.0
Net income (loss) including noncontrolling interests									1,414.2	1,993.0	395.2
Net (income) loss attributable to noncontrolling interests									0.0	0.0	0.0
Net income (loss) attributable to Molson Coors Brewing Company									1,414.2	1,993.0	395.2
Amounts attributable to Molson Coors Brewing Company
Income (loss) from discontinued operations, net of tax									0.0	0.0	0.0
Net income (loss) attributable to Molson Coors Brewing Company									1,414.2	1,993.0	395.2
Subsidiary Guarantors
Sales Revenue, Goods, Gross									10,457.9	3,742.8	2,070.4
Sales									8,982.8	3,081.4	1,596.5
Excise taxes									(1,475.1)	(661.4)	(473.9)
Cost of goods sold									(5,028.3)	(1,827.6)	(886.7)
Gross profit									3,954.5	1,253.8	709.8
Marketing, general and administrative expenses									(2,164.8)	(802.4)	(368.8)
Special items, net									(21.5)	2,554.8	(27.2)
Equity Income Loss in Equity Method Investment										500.9	516.3
Operating income (loss)									1,482.5	3,166.7	370.4
Other income (expense), net
Other income (expense), net									178.9	(60.9)	6.3
Income tax benefit (expense)									(86.6)	(1,108.0)	(214.5)
Net income (loss) from continuing operations									1,850.4	2,266.7	452.3
Income (loss) from discontinued operations, net of tax									0.0	0.0	0.0
Net income (loss) including noncontrolling interests									1,850.4	2,266.7	452.3
Net (income) loss attributable to noncontrolling interests									0.0	0.0	0.0
Net income (loss) attributable to Molson Coors Brewing Company									1,850.4	2,266.7	452.3
Amounts attributable to Molson Coors Brewing Company
Income (loss) from discontinued operations, net of tax									0.0	0.0	0.0
Net income (loss) attributable to Molson Coors Brewing Company									1,850.4	2,266.7	452.3
Subsidiary Non Guarantors
Sales Revenue, Goods, Gross									3,513.7	3,044.3	3,141.3
Sales									2,520.1	1,993.3	2,055.3
Excise taxes									(993.6)	(1,051.0)	(1,086.0)
Cost of goods sold									(1,673.9)	(1,345.5)	(1,325.1)
Gross profit									846.2	647.8	730.2
Marketing, general and administrative expenses									(617.7)	(568.4)	(570.8)
Special items, net									(5.8)	(31.4)	(319.5)
Equity Income Loss in Equity Method Investment										0.0	0.0
Operating income (loss)									416.1	(71.1)	112.7
Other income (expense), net
Other income (expense), net									(170.5)	93.2	2.0
Income tax benefit (expense)									(6.7)	(159.6)	48.6
Net income (loss) from continuing operations									(71.6)	(448.7)	(171.3)
Income (loss) from discontinued operations, net of tax									1.5	(2.8)	3.9
Net income (loss) including noncontrolling interests									(70.1)	(451.5)	(167.4)
Net (income) loss attributable to noncontrolling interests									(22.2)	(5.9)	(3.3)
Net income (loss) attributable to Molson Coors Brewing Company									(92.3)	(457.4)	(170.7)
Amounts attributable to Molson Coors Brewing Company
Income (loss) from discontinued operations, net of tax									1.5	(2.8)	3.9
Net income (loss) attributable to Molson Coors Brewing Company									$ (92.3)	$ (457.4)	$ (170.7)