Basis of Presentation and Summary of Significant Accounting Policies Foreign Currency Translation (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended		6 Months Ended	3 Months Ended		6 Months Ended
	Sep. 28, 2013	Sep. 29, 2012	Sep. 28, 2013	Sep. 29, 2012	Jun. 29, 2013 As Reported [Member]	Mar. 30, 2013 As Reported [Member]	Jun. 29, 2013 As Reported [Member]	Jun. 29, 2013 As Adjusted [Member]	Mar. 30, 2013 As Adjusted [Member]	Jun. 29, 2013 As Adjusted [Member]
Foreign currency translation adjustments, net of tax	$ 270.7	$ 258.3	$ (124.1)	$ 301.9	$ (79.4)	$ (261.3)	$ (340.7)	$ (114.1)	$ (280.7)	$ (394.8)
Total other comprehensive income (loss), net of tax	281.9	263.3	(66.5)	325.0	(52.5)	(241.8)	(294.3)	(87.2)	(261.2)	(348.4)
Comprehensive income (loss) attributable to Molson Coors Brewing Company	$ 403.7	$ 461.7	$ 369.3	$ 708.0	$ 225.9	$ (206.2)	$ 19.7	$ 191.2	$ (225.6)	$ (34.4)