Pension and Other Postretirement Benefits (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended
	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2012 Defined Benefit Plans	Jun. 25, 2011 Defined Benefit Plans	Jun. 30, 2012 Defined Benefit Plans	Jun. 25, 2011 Defined Benefit Plans	Jun. 30, 2012 Canada Defined Benefit Plans	Jun. 25, 2011 Canada Defined Benefit Plans	Jun. 30, 2012 Canada Defined Benefit Plans	Jun. 25, 2011 Canada Defined Benefit Plans	Jun. 30, 2012 U.S. Benefit Plans	Jun. 25, 2011 U.S. Benefit Plans	Jun. 30, 2012 U.S. Benefit Plans	Jun. 25, 2011 U.S. Benefit Plans	Jun. 30, 2012 U.K. Defined Benefit Plans	Jun. 25, 2011 U.K. Defined Benefit Plans	Jun. 30, 2012 U.K. Defined Benefit Plans	Jun. 25, 2011 U.K. Defined Benefit Plans	Jun. 30, 2012 MCI	Jun. 30, 2012 MCI	Jun. 30, 2012 Other Postretirement Benefits	Jun. 25, 2011 Other Postretirement Benefits	Jun. 30, 2012 Other Postretirement Benefits	Jun. 25, 2011 Other Postretirement Benefits	Jun. 30, 2012 Canada Other Postretirement Benefits	Jun. 25, 2011 Canada Other Postretirement Benefits	Jun. 30, 2012 Canada Other Postretirement Benefits	Jun. 25, 2011 Canada Other Postretirement Benefits	Jun. 30, 2012 U.S. Other Postretirement Benefits	Jun. 25, 2011 U.S. Other Postretirement Benefits	Jun. 30, 2012 U.S. Other Postretirement Benefits	Jun. 25, 2011 U.S. Other Postretirement Benefits	Jun. 15, 2012 Molson Coors Central Europe (MCCE) [Member]
Pension and other post-retirement benefits details:
Pension and Other Postretirement Defined Benefit Plans, Liabilities, Noncurrent	$ 687.2	$ 697.5																															$ 2.7
Net periodic pension costs under retirement plans and other postretirement benefits:
Service cost - benefits earned during the period			4.2	4.8	8.4	9.5	4.1	4.8	8.2	9.5									0.1	0.2	0.7	0.6	1.4	1.2	0.6	0.5	1.2	1.0	0.1	0.1	0.2	0.2
Interest cost on projected benefit obligation			41.4	46.1	82.5	91.2	16.6	18.5	33.2	36.6	0	0.1		0.2	24.8	27.5	49.3	54.4			1.9	2.0	3.9	3.9	1.9	2.0	3.9	3.9
Expected return on plan assets			(43.7)	(50.7)	(87.2)	(100.5)	(15.2)	(18.8)	(30.5)	(37.4)					(28.5)	(31.9)	(56.7)	(63.1)
Amortization of prior service cost (gain)			0.2	0.2	0.4	0.4	0.2	0.2	0.4	0.4											(0.9)	(1.0)	(1.8)	(1.9)	(0.9)	(1.0)	(1.8)	(1.9)
Amortization of net actuarial loss (gain)			9.8	5.2	19.6	10.2	5.4	2.4	10.8	4.7					4.4	2.8	8.8	5.5			(0.1)	(0.9)	(0.2)	(1.8)	(0.1)	(0.9)	(0.2)	(1.8)
Less expected participant contributions			(0.4)	(0.4)	(0.8)	(0.8)	(0.4)	(0.4)	(0.8)	(0.8)
Curtailment loss				0		0		0		0
Net periodic pension and postretirement benefit cost			11.5	5.2	22.9	10.0	10.7	6.7	21.3	13.0	0	0.1	0	0.2	0.7	(1.6)	1.4	(3.2)	0.1	0.2	1.6	0.7	3.3	1.4	1.5	0.6	3.1	1.2	0.1	0.1	0.2	0.2
Contributions paid to defined benefit plans									21.4											0.4
Expected total defined benefit plan employer contributions for fiscal year 2011	60
Future Pension and Post-retirement Expenses, Remainder of Fiscal Year	$ 0.2