Earnings per Share ("EPS") Basic and Diluted (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Amounts attributable to MCBC
Net income (loss) from continuing operations	$ 79.2		$ 165.3
Income (loss) from discontinued operations, net of tax	1.9		(1.9)
Net income (loss) attributable to Molson Coors Brewing Company	$ 81.1		$ 163.4
Weighted average shares for basic EPS (in shares)	185.8		184.3
Effect of dilutive securities:
Weighted average shares for diluted EPS (in shares)	186.9		185.5
Basic net income (loss) per share:
Continuing operations attributable to MCBC (in dollars per share)	$ 0.43	[1]	$ 0.90	[1]
Discontinued operations attributable to MCBC (in dollars per share)	$ 0.01	[1]	$ (0.01)	[1]
Net income attributable to MCBC (in dollars per share)	$ 0.44	[1]	$ 0.89	[1]
Diluted net income (loss) per share:
Continuing operations attributable to MCBC (in dollars per share)	$ 0.42	[1]	$ 0.89	[1]
Discontinued operations attributable to MCBC (in dollars per share)	$ 0.01	[1]	$ (0.01)	[1]
Net income attributable to MCBC (in dollars per share)	$ 0.43	[1]	$ 0.88	[1]
Dividends declared per share (in dollars per share)	$ 0.41		$ 0.37
RSU DSU PU PSU [Member]
Effect of dilutive securities:
Effect of dilutive securities of RSU's, DSU's, PU's, Options and SOSAR's	0.5		0.6
Options and Sosars [Member]
Effect of dilutive securities:
Effect of dilutive securities of RSU's, DSU's, PU's, Options and SOSAR's	0.6		0.6

[1] The sum of the quarterly net income per share amounts may not agree to the full year net income per share amounts. We calculate net income per share based on the weighted-average number of outstanding shares during the period for each reporting period presented. The average number of shares fluctuates throughout the year and can therefore produce a full year result that does not agree to the sum of the individual quarters.